initial sabre upgrade (needs lots of work - to wit: authentication, redo the browser interface, and rework event export/import)

27 files changed, 4622 insertions, 0 deletions

diff --git a/vendor/sabre/dav/lib/DAVACL/AbstractPrincipalCollection.php b/vendor/sabre/dav/lib/DAVACL/AbstractPrincipalCollection.php
new file mode 100644
index 000000000..460f78981
--- /dev/null
+++ b/vendor/sabre/dav/lib/DAVACL/AbstractPrincipalCollection.php
@@ -0,0 +1,181 @@
+<?php
+
+namespace Sabre\DAVACL;
+
+use Sabre\DAV;
+use Sabre\HTTP\URLUtil;
+
+/**
+ * Principals Collection
+ *
+ * This is a helper class that easily allows you to create a collection that
+ * has a childnode for every principal.
+ *
+ * To use this class, simply implement the getChildForPrincipal method.
+ *
+ * @copyright Copyright (C) fruux GmbH (https://fruux.com/)
+ * @author Evert Pot (http://evertpot.com/)
+ * @license http://sabre.io/license/ Modified BSD License
+ */
+abstract class AbstractPrincipalCollection extends DAV\Collection implements IPrincipalCollection {
+
+    /**
+     * Principal backend
+     *
+     * @var PrincipalBackend\BackendInterface
+     */
+    protected $principalBackend;
+
+    /**
+     * The path to the principals we're listing from.
+     *
+     * @var string
+     */
+    protected $principalPrefix;
+
+    /**
+     * If this value is set to true, it effectively disables listing of users
+     * it still allows user to find other users if they have an exact url.
+     *
+     * @var bool
+     */
+    public $disableListing = false;
+
+    /**
+     * Creates the object
+     *
+     * This object must be passed the principal backend. This object will
+     * filter all principals from a specified prefix ($principalPrefix). The
+     * default is 'principals', if your principals are stored in a different
+     * collection, override $principalPrefix
+     *
+     *
+     * @param PrincipalBackend\BackendInterface $principalBackend
+     * @param string $principalPrefix
+     */
+    function __construct(PrincipalBackend\BackendInterface $principalBackend, $principalPrefix = 'principals') {
+
+        $this->principalPrefix = $principalPrefix;
+        $this->principalBackend = $principalBackend;
+
+    }
+
+    /**
+     * This method returns a node for a principal.
+     *
+     * The passed array contains principal information, and is guaranteed to
+     * at least contain a uri item. Other properties may or may not be
+     * supplied by the authentication backend.
+     *
+     * @param array $principalInfo
+     * @return IPrincipal
+     */
+    abstract function getChildForPrincipal(array $principalInfo);
+
+    /**
+     * Returns the name of this collection.
+     *
+     * @return string
+     */
+    function getName() {
+
+        list(, $name) = URLUtil::splitPath($this->principalPrefix);
+        return $name;
+
+    }
+
+    /**
+     * Return the list of users
+     *
+     * @return array
+     */
+    function getChildren() {
+
+        if ($this->disableListing)
+            throw new DAV\Exception\MethodNotAllowed('Listing members of this collection is disabled');
+
+        $children = [];
+        foreach ($this->principalBackend->getPrincipalsByPrefix($this->principalPrefix) as $principalInfo) {
+
+            $children[] = $this->getChildForPrincipal($principalInfo);
+
+
+        }
+        return $children;
+
+    }
+
+    /**
+     * Returns a child object, by its name.
+     *
+     * @param string $name
+     * @throws DAV\Exception\NotFound
+     * @return IPrincipal
+     */
+    function getChild($name) {
+
+        $principalInfo = $this->principalBackend->getPrincipalByPath($this->principalPrefix . '/' . $name);
+        if (!$principalInfo) throw new DAV\Exception\NotFound('Principal with name ' . $name . ' not found');
+        return $this->getChildForPrincipal($principalInfo);
+
+    }
+
+    /**
+     * This method is used to search for principals matching a set of
+     * properties.
+     *
+     * This search is specifically used by RFC3744's principal-property-search
+     * REPORT. You should at least allow searching on
+     * http://sabredav.org/ns}email-address.
+     *
+     * The actual search should be a unicode-non-case-sensitive search. The
+     * keys in searchProperties are the WebDAV property names, while the values
+     * are the property values to search on.
+     *
+     * By default, if multiple properties are submitted to this method, the
+     * various properties should be combined with 'AND'. If $test is set to
+     * 'anyof', it should be combined using 'OR'.
+     *
+     * This method should simply return a list of 'child names', which may be
+     * used to call $this->getChild in the future.
+     *
+     * @param array $searchProperties
+     * @param string $test
+     * @return array
+     */
+    function searchPrincipals(array $searchProperties, $test = 'allof') {
+
+        $result = $this->principalBackend->searchPrincipals($this->principalPrefix, $searchProperties, $test);
+        $r = [];
+
+        foreach ($result as $row) {
+            list(, $r[]) = URLUtil::splitPath($row);
+        }
+
+        return $r;
+
+    }
+
+    /**
+     * Finds a principal by its URI.
+     *
+     * This method may receive any type of uri, but mailto: addresses will be
+     * the most common.
+     *
+     * Implementation of this API is optional. It is currently used by the
+     * CalDAV system to find principals based on their email addresses. If this
+     * API is not implemented, some features may not work correctly.
+     *
+     * This method must return a relative principal path, or null, if the
+     * principal was not found or you refuse to find it.
+     *
+     * @param string $uri
+     * @return string
+     */
+    function findByUri($uri) {
+
+        return $this->principalBackend->findByUri($uri, $this->principalPrefix);
+
+    }
+
+}
diff --git a/vendor/sabre/dav/lib/DAVACL/Exception/AceConflict.php b/vendor/sabre/dav/lib/DAVACL/Exception/AceConflict.php
new file mode 100644
index 000000000..22450b4a6
--- /dev/null
+++ b/vendor/sabre/dav/lib/DAVACL/Exception/AceConflict.php
@@ -0,0 +1,35 @@
+<?php
+
+namespace Sabre\DAVACL\Exception;
+
+use Sabre\DAV;
+
+/**
+ * This exception is thrown when a client attempts to set conflicting
+ * permissions.
+ *
+ * @copyright Copyright (C) fruux GmbH (https://fruux.com/)
+ * @author Evert Pot (http://evertpot.com/)
+ * @license http://sabre.io/license/ Modified BSD License
+ */
+class AceConflict extends DAV\Exception\Conflict {
+
+    /**
+     * Adds in extra information in the xml response.
+     *
+     * This method adds the {DAV:}no-ace-conflict element as defined in rfc3744
+     *
+     * @param DAV\Server $server
+     * @param \DOMElement $errorNode
+     * @return void
+     */
+    function serialize(DAV\Server $server, \DOMElement $errorNode) {
+
+        $doc = $errorNode->ownerDocument;
+
+        $np = $doc->createElementNS('DAV:', 'd:no-ace-conflict');
+        $errorNode->appendChild($np);
+
+    }
+
+}
diff --git a/vendor/sabre/dav/lib/DAVACL/Exception/NeedPrivileges.php b/vendor/sabre/dav/lib/DAVACL/Exception/NeedPrivileges.php
new file mode 100644
index 000000000..5624fd22f
--- /dev/null
+++ b/vendor/sabre/dav/lib/DAVACL/Exception/NeedPrivileges.php
@@ -0,0 +1,82 @@
+<?php
+
+namespace Sabre\DAVACL\Exception;
+
+use Sabre\DAV;
+
+/**
+ * NeedPrivileges
+ *
+ * The 403-need privileges is thrown when a user didn't have the appropriate
+ * permissions to perform an operation
+ *
+ * @copyright Copyright (C) fruux GmbH (https://fruux.com/)
+ * @author Evert Pot (http://evertpot.com/)
+ * @license http://sabre.io/license/ Modified BSD License
+ */
+class NeedPrivileges extends DAV\Exception\Forbidden {
+
+    /**
+     * The relevant uri
+     *
+     * @var string
+     */
+    protected $uri;
+
+    /**
+     * The privileges the user didn't have.
+     *
+     * @var array
+     */
+    protected $privileges;
+
+    /**
+     * Constructor
+     *
+     * @param string $uri
+     * @param array $privileges
+     */
+    function __construct($uri, array $privileges) {
+
+        $this->uri = $uri;
+        $this->privileges = $privileges;
+
+        parent::__construct('User did not have the required privileges (' . implode(',', $privileges) . ') for path "' . $uri . '"');
+
+    }
+
+    /**
+     * Adds in extra information in the xml response.
+     *
+     * This method adds the {DAV:}need-privileges element as defined in rfc3744
+     *
+     * @param DAV\Server $server
+     * @param \DOMElement $errorNode
+     * @return void
+     */
+    function serialize(DAV\Server $server, \DOMElement $errorNode) {
+
+        $doc = $errorNode->ownerDocument;
+
+        $np = $doc->createElementNS('DAV:', 'd:need-privileges');
+        $errorNode->appendChild($np);
+
+        foreach ($this->privileges as $privilege) {
+
+            $resource = $doc->createElementNS('DAV:', 'd:resource');
+            $np->appendChild($resource);
+
+            $resource->appendChild($doc->createElementNS('DAV:', 'd:href', $server->getBaseUri() . $this->uri));
+
+            $priv = $doc->createElementNS('DAV:', 'd:privilege');
+            $resource->appendChild($priv);
+
+            preg_match('/^{([^}]*)}(.*)$/', $privilege, $privilegeParts);
+            $priv->appendChild($doc->createElementNS($privilegeParts[1], 'd:' . $privilegeParts[2]));
+
+
+        }
+
+    }
+
+}
diff --git a/vendor/sabre/dav/lib/DAVACL/Exception/NoAbstract.php b/vendor/sabre/dav/lib/DAVACL/Exception/NoAbstract.php
new file mode 100644
index 000000000..a2363b174
--- /dev/null
+++ b/vendor/sabre/dav/lib/DAVACL/Exception/NoAbstract.php
@@ -0,0 +1,35 @@
+<?php
+
+namespace Sabre\DAVACL\Exception;
+
+use Sabre\DAV;
+
+/**
+ * This exception is thrown when a user tries to set a privilege that's marked
+ * as abstract.
+ *
+ * @copyright Copyright (C) fruux GmbH (https://fruux.com/)
+ * @author Evert Pot (http://evertpot.com/)
+ * @license http://sabre.io/license/ Modified BSD License
+ */
+class NoAbstract extends DAV\Exception\PreconditionFailed {
+
+    /**
+     * Adds in extra information in the xml response.
+     *
+     * This method adds the {DAV:}no-abstract element as defined in rfc3744
+     *
+     * @param DAV\Server $server
+     * @param \DOMElement $errorNode
+     * @return void
+     */
+    function serialize(DAV\Server $server, \DOMElement $errorNode) {
+
+        $doc = $errorNode->ownerDocument;
+
+        $np = $doc->createElementNS('DAV:', 'd:no-abstract');
+        $errorNode->appendChild($np);
+
+    }
+
+}
diff --git a/vendor/sabre/dav/lib/DAVACL/Exception/NotRecognizedPrincipal.php b/vendor/sabre/dav/lib/DAVACL/Exception/NotRecognizedPrincipal.php
new file mode 100644
index 000000000..4349bf101
--- /dev/null
+++ b/vendor/sabre/dav/lib/DAVACL/Exception/NotRecognizedPrincipal.php
@@ -0,0 +1,35 @@
+<?php
+
+namespace Sabre\DAVACL\Exception;
+
+use Sabre\DAV;
+
+/**
+ * If a client tried to set a privilege assigned to a non-existant principal,
+ * this exception will be thrown.
+ *
+ * @copyright Copyright (C) fruux GmbH (https://fruux.com/)
+ * @author Evert Pot (http://evertpot.com/)
+ * @license http://sabre.io/license/ Modified BSD License
+ */
+class NotRecognizedPrincipal extends DAV\Exception\PreconditionFailed {
+
+    /**
+     * Adds in extra information in the xml response.
+     *
+     * This method adds the {DAV:}recognized-principal element as defined in rfc3744
+     *
+     * @param DAV\Server $server
+     * @param \DOMElement $errorNode
+     * @return void
+     */
+    function serialize(DAV\Server $server, \DOMElement $errorNode) {
+
+        $doc = $errorNode->ownerDocument;
+
+        $np = $doc->createElementNS('DAV:', 'd:recognized-principal');
+        $errorNode->appendChild($np);
+
+    }
+
+}
diff --git a/vendor/sabre/dav/lib/DAVACL/Exception/NotSupportedPrivilege.php b/vendor/sabre/dav/lib/DAVACL/Exception/NotSupportedPrivilege.php
new file mode 100644
index 000000000..73b81190d
--- /dev/null
+++ b/vendor/sabre/dav/lib/DAVACL/Exception/NotSupportedPrivilege.php
@@ -0,0 +1,35 @@
+<?php
+
+namespace Sabre\DAVACL\Exception;
+
+use Sabre\DAV;
+
+/**
+ * If a client tried to set a privilege that doesn't exist, this exception will
+ * be thrown.
+ *
+ * @copyright Copyright (C) fruux GmbH (https://fruux.com/)
+ * @author Evert Pot (http://evertpot.com/)
+ * @license http://sabre.io/license/ Modified BSD License
+ */
+class NotSupportedPrivilege extends DAV\Exception\PreconditionFailed {
+
+    /**
+     * Adds in extra information in the xml response.
+     *
+     * This method adds the {DAV:}not-supported-privilege element as defined in rfc3744
+     *
+     * @param DAV\Server $server
+     * @param \DOMElement $errorNode
+     * @return void
+     */
+    function serialize(DAV\Server $server, \DOMElement $errorNode) {
+
+        $doc = $errorNode->ownerDocument;
+
+        $np = $doc->createElementNS('DAV:', 'd:not-supported-privilege');
+        $errorNode->appendChild($np);
+
+    }
+
+}
diff --git a/vendor/sabre/dav/lib/DAVACL/FS/Collection.php b/vendor/sabre/dav/lib/DAVACL/FS/Collection.php
new file mode 100644
index 000000000..5fab4768c
--- /dev/null
+++ b/vendor/sabre/dav/lib/DAVACL/FS/Collection.php
@@ -0,0 +1,153 @@
+<?php
+
+namespace Sabre\DAVACL\FS;
+
+use Sabre\DAV\FSExt\Directory as BaseCollection;
+use Sabre\DAVACL\IACL;
+use Sabre\DAV\Exception\Forbidden;
+use Sabre\DAV\Exception\NotFound;
+
+/**
+ * This is an ACL-enabled collection.
+ *
+ * @copyright Copyright (C) fruux GmbH (https://fruux.com/)
+ * @author Evert Pot (http://evertpot.com/)
+ * @license http://sabre.io/license/ Modified BSD License
+ */
+class Collection extends BaseCollection implements IACL {
+
+    /**
+     * A list of ACL rules.
+     *
+     * @var array
+     */
+    protected $acl;
+
+    /**
+     * Owner uri, or null for no owner.
+     *
+     * @var string|null
+     */
+    protected $owner;
+
+    /**
+     * Constructor
+     *
+     * @param string $path on-disk path.
+     * @param array $acl ACL rules.
+     * @param string|null $owner principal owner string.
+     */
+    function __construct($path, array $acl, $owner = null) {
+
+        parent::__construct($path);
+        $this->acl = $acl;
+        $this->owner = $owner;
+
+    }
+
+    /**
+     * Returns a specific child node, referenced by its name
+     *
+     * This method must throw Sabre\DAV\Exception\NotFound if the node does not
+     * exist.
+     *
+     * @param string $name
+     * @throws DAV\Exception\NotFound
+     * @return DAV\INode
+     */
+    function getChild($name) {
+
+        $path = $this->path . '/' . $name;
+
+        if (!file_exists($path)) throw new NotFound('File could not be located');
+        if ($name == '.' || $name == '..') throw new Forbidden('Permission denied to . and ..');
+
+        if (is_dir($path)) {
+
+            return new self($path, $this->acl, $this->owner);
+
+        } else {
+
+            return new File($path, $this->acl, $this->owner);
+
+        }
+
+    }
+
+    /**
+     * Returns the owner principal
+     *
+     * This must be a url to a principal, or null if there's no owner
+     *
+     * @return string|null
+     */
+    function getOwner() {
+
+        return $this->owner;
+
+    }
+
+    /**
+     * Returns a group principal
+     *
+     * This must be a url to a principal, or null if there's no owner
+     *
+     * @return string|null
+     */
+    function getGroup() {
+
+        return null;
+
+    }
+
+    /**
+     * Returns a list of ACE's for this node.
+     *
+     * Each ACE has the following properties:
+     *   * 'privilege', a string such as {DAV:}read or {DAV:}write. These are
+     *     currently the only supported privileges
+     *   * 'principal', a url to the principal who owns the node
+     *   * 'protected' (optional), indicating that this ACE is not allowed to
+     *      be updated.
+     *
+     * @return array
+     */
+    function getACL() {
+
+        return $this->acl;
+
+    }
+
+    /**
+     * Updates the ACL
+     *
+     * This method will receive a list of new ACE's as an array argument.
+     *
+     * @param array $acl
+     * @return void
+     */
+    function setACL(array $acl) {
+
+        throw new Forbidden('Setting ACL is not allowed here');
+
+    }
+
+    /**
+     * Returns the list of supported privileges for this node.
+     *
+     * The returned data structure is a list of nested privileges.
+     * See Sabre\DAVACL\Plugin::getDefaultSupportedPrivilegeSet for a simple
+     * standard structure.
+     *
+     * If null is returned from this method, the default privilege set is used,
+     * which is fine for most common usecases.
+     *
+     * @return array|null
+     */
+    function getSupportedPrivilegeSet() {
+
+        return null;
+
+    }
+
+}
diff --git a/vendor/sabre/dav/lib/DAVACL/FS/File.php b/vendor/sabre/dav/lib/DAVACL/FS/File.php
new file mode 100644
index 000000000..0d549528b
--- /dev/null
+++ b/vendor/sabre/dav/lib/DAVACL/FS/File.php
@@ -0,0 +1,123 @@
+<?php
+
+namespace Sabre\DAVACL\FS;
+
+use Sabre\DAV\FSExt\File as BaseFile;
+use Sabre\DAVACL\IACL;
+use Sabre\DAV\Exception\Forbidden;
+
+/**
+ * This is an ACL-enabled file node.
+ *
+ * @copyright Copyright (C) fruux GmbH (https://fruux.com/)
+ * @author Evert Pot (http://evertpot.com/)
+ * @license http://sabre.io/license/ Modified BSD License
+ */
+class File extends BaseFile implements IACL {
+
+    /**
+     * A list of ACL rules.
+     *
+     * @var array
+     */
+    protected $acl;
+
+    /**
+     * Owner uri, or null for no owner.
+     *
+     * @var string|null
+     */
+    protected $owner;
+
+    /**
+     * Constructor
+     *
+     * @param string $path on-disk path.
+     * @param array $acl ACL rules.
+     * @param string|null $owner principal owner string.
+     */
+    function __construct($path, array $acl, $owner = null) {
+
+        parent::__construct($path);
+        $this->acl = $acl;
+        $this->owner = $owner;
+
+    }
+
+    /**
+     * Returns the owner principal
+     *
+     * This must be a url to a principal, or null if there's no owner
+     *
+     * @return string|null
+     */
+    function getOwner() {
+
+        return $this->owner;
+
+    }
+
+    /**
+     * Returns a group principal
+     *
+     * This must be a url to a principal, or null if there's no owner
+     *
+     * @return string|null
+     */
+    function getGroup() {
+
+        return null;
+
+    }
+
+    /**
+     * Returns a list of ACE's for this node.
+     *
+     * Each ACE has the following properties:
+     *   * 'privilege', a string such as {DAV:}read or {DAV:}write. These are
+     *     currently the only supported privileges
+     *   * 'principal', a url to the principal who owns the node
+     *   * 'protected' (optional), indicating that this ACE is not allowed to
+     *      be updated.
+     *
+     * @return array
+     */
+    function getACL() {
+
+        return $this->acl;
+
+    }
+
+    /**
+     * Updates the ACL
+     *
+     * This method will receive a list of new ACE's as an array argument.
+     *
+     * @param array $acl
+     * @return void
+     */
+    function setACL(array $acl) {
+
+        throw new Forbidden('Setting ACL is not allowed here');
+
+    }
+
+    /**
+     * Returns the list of supported privileges for this node.
+     *
+     * The returned data structure is a list of nested privileges.
+     * See Sabre\DAVACL\Plugin::getDefaultSupportedPrivilegeSet for a simple
+     * standard structure.
+     *
+     * If null is returned from this method, the default privilege set is used,
+     * which is fine for most common usecases.
+     *
+     * @return array|null
+     */
+    function getSupportedPrivilegeSet() {
+
+        return null;
+
+    }
+
+}
diff --git a/vendor/sabre/dav/lib/DAVACL/FS/HomeCollection.php b/vendor/sabre/dav/lib/DAVACL/FS/HomeCollection.php
new file mode 100644
index 000000000..c27616770
--- /dev/null
+++ b/vendor/sabre/dav/lib/DAVACL/FS/HomeCollection.php
@@ -0,0 +1,188 @@
+<?php
+
+namespace Sabre\DAVACL\FS;
+
+use Sabre\DAV\Exception\Forbidden;
+use Sabre\DAVACL\AbstractPrincipalCollection;
+use Sabre\DAVACL\IACL;
+use Sabre\DAVACL\PrincipalBackend\BackendInterface;
+use Sabre\Uri;
+
+/**
+ * This collection contains a collection for every principal.
+ * It is similar to /home on many unix systems.
+ *
+ * The per-user collections can only be accessed by the user who owns the
+ * collection.
+ *
+ * @copyright Copyright (C) fruux GmbH (https://fruux.com/)
+ * @author Evert Pot (http://evertpot.com/)
+ * @license http://sabre.io/license/ Modified BSD License
+ */
+class HomeCollection extends AbstractPrincipalCollection implements IACL {
+
+    /**
+     * Name of this collection.
+     *
+     * @var string
+     */
+    public $collectionName = 'home';
+
+    /**
+     * Path to where the users' files are actually stored.
+     *
+     * @var string
+     */
+    protected $storagePath;
+
+    /**
+     * Creates the home collection.
+     *
+     * @param BackendInterface $principalBackend
+     * @param string $storagePath Where the actual files are stored.
+     * @param string $principalPrefix list of principals to iterate.
+     */
+    function __construct(BackendInterface $principalBackend, $storagePath, $principalPrefix = 'principals') {
+
+        parent::__construct($principalBackend, $principalPrefix);
+        $this->storagePath = $storagePath;
+
+    }
+
+    /**
+     * Returns the name of the node.
+     *
+     * This is used to generate the url.
+     *
+     * @return string
+     */
+    function getName() {
+
+        return $this->collectionName;
+
+    }
+
+    /**
+     * Returns a principals' collection of files.
+     *
+     * The passed array contains principal information, and is guaranteed to
+     * at least contain a uri item. Other properties may or may not be
+     * supplied by the authentication backend.
+     *
+     * @param array $principalInfo
+     * @return void
+     */
+    function getChildForPrincipal(array $principalInfo) {
+
+        $owner = $principalInfo['uri'];
+        $acl = [
+            [
+                'privilege' => '{DAV:}read',
+                'principal' => $owner,
+                'protected' => true,
+            ],
+            [
+                'privilege' => '{DAV:}write',
+                'principal' => $owner,
+                'protected' => true,
+            ],
+        ];
+
+        list(, $principalBaseName) = Uri\split($owner);
+
+        $path = $this->storagePath . '/' . $principalBaseName;
+
+        if (!is_dir($path)) {
+            mkdir($path, 0777, true);
+        }
+        return new Collection(
+            $path,
+            $acl,
+            $owner
+        );
+
+    }
+
+    /**
+     * Returns the owner principal
+     *
+     * This must be a url to a principal, or null if there's no owner
+     *
+     * @return string|null
+     */
+    function getOwner() {
+
+        return null;
+
+    }
+
+    /**
+     * Returns a group principal
+     *
+     * This must be a url to a principal, or null if there's no owner
+     *
+     * @return string|null
+     */
+    function getGroup() {
+
+        return null;
+
+    }
+
+    /**
+     * Returns a list of ACE's for this node.
+     *
+     * Each ACE has the following properties:
+     *   * 'privilege', a string such as {DAV:}read or {DAV:}write. These are
+     *     currently the only supported privileges
+     *   * 'principal', a url to the principal who owns the node
+     *   * 'protected' (optional), indicating that this ACE is not allowed to
+     *      be updated.
+     *
+     * @return array
+     */
+    function getACL() {
+
+        return [
+            [
+                'principal' => '{DAV:}authenticated',
+                'privilege' => '{DAV:}read',
+                'protected' => true,
+            ]
+        ];
+
+    }
+
+    /**
+     * Updates the ACL
+     *
+     * This method will receive a list of new ACE's as an array argument.
+     *
+     * @param array $acl
+     * @return void
+     */
+    function setACL(array $acl) {
+
+        throw new Forbidden('Setting ACL is not allowed here');
+
+    }
+
+    /**
+     * Returns the list of supported privileges for this node.
+     *
+     * The returned data structure is a list of nested privileges.
+     * See Sabre\DAVACL\Plugin::getDefaultSupportedPrivilegeSet for a simple
+     * standard structure.
+     *
+     * If null is returned from this method, the default privilege set is used,
+     * which is fine for most common usecases.
+     *
+     * @return array|null
+     */
+    function getSupportedPrivilegeSet() {
+
+        return null;
+
+    }
+
+}
diff --git a/vendor/sabre/dav/lib/DAVACL/IACL.php b/vendor/sabre/dav/lib/DAVACL/IACL.php
new file mode 100644
index 000000000..81908d08f
--- /dev/null
+++ b/vendor/sabre/dav/lib/DAVACL/IACL.php
@@ -0,0 +1,75 @@
+<?php
+
+namespace Sabre\DAVACL;
+
+use Sabre\DAV;
+
+/**
+ * ACL-enabled node
+ *
+ * If you want to add WebDAV ACL to a node, you must implement this class
+ *
+ * @copyright Copyright (C) fruux GmbH (https://fruux.com/)
+ * @author Evert Pot (http://evertpot.com/)
+ * @license http://sabre.io/license/ Modified BSD License
+ */
+interface IACL extends DAV\INode {
+
+    /**
+     * Returns the owner principal
+     *
+     * This must be a url to a principal, or null if there's no owner
+     *
+     * @return string|null
+     */
+    function getOwner();
+
+    /**
+     * Returns a group principal
+     *
+     * This must be a url to a principal, or null if there's no owner
+     *
+     * @return string|null
+     */
+    function getGroup();
+
+    /**
+     * Returns a list of ACE's for this node.
+     *
+     * Each ACE has the following properties:
+     *   * 'privilege', a string such as {DAV:}read or {DAV:}write. These are
+     *     currently the only supported privileges
+     *   * 'principal', a url to the principal who owns the node
+     *   * 'protected' (optional), indicating that this ACE is not allowed to
+     *      be updated.
+     *
+     * @return array
+     */
+    function getACL();
+
+    /**
+     * Updates the ACL
+     *
+     * This method will receive a list of new ACE's as an array argument.
+     *
+     * @param array $acl
+     * @return void
+     */
+    function setACL(array $acl);
+
+    /**
+     * Returns the list of supported privileges for this node.
+     *
+     * The returned data structure is a list of nested privileges.
+     * See Sabre\DAVACL\Plugin::getDefaultSupportedPrivilegeSet for a simple
+     * standard structure.
+     *
+     * If null is returned from this method, the default privilege set is used,
+     * which is fine for most common usecases.
+     *
+     * @return array|null
+     */
+    function getSupportedPrivilegeSet();
+
+
+}
diff --git a/vendor/sabre/dav/lib/DAVACL/IPrincipal.php b/vendor/sabre/dav/lib/DAVACL/IPrincipal.php
new file mode 100644
index 000000000..13728471e
--- /dev/null
+++ b/vendor/sabre/dav/lib/DAVACL/IPrincipal.php
@@ -0,0 +1,77 @@
+<?php
+
+namespace Sabre\DAVACL;
+
+use Sabre\DAV;
+
+/**
+ * IPrincipal interface
+ *
+ * Implement this interface to define your own principals
+ *
+ * @copyright Copyright (C) fruux GmbH (https://fruux.com/)
+ * @author Evert Pot (http://evertpot.com/)
+ * @license http://sabre.io/license/ Modified BSD License
+ */
+interface IPrincipal extends DAV\INode {
+
+    /**
+     * Returns a list of alternative urls for a principal
+     *
+     * This can for example be an email address, or ldap url.
+     *
+     * @return array
+     */
+    function getAlternateUriSet();
+
+    /**
+     * Returns the full principal url
+     *
+     * @return string
+     */
+    function getPrincipalUrl();
+
+    /**
+     * Returns the list of group members
+     *
+     * If this principal is a group, this function should return
+     * all member principal uri's for the group.
+     *
+     * @return array
+     */
+    function getGroupMemberSet();
+
+    /**
+     * Returns the list of groups this principal is member of
+     *
+     * If this principal is a member of a (list of) groups, this function
+     * should return a list of principal uri's for it's members.
+     *
+     * @return array
+     */
+    function getGroupMembership();
+
+    /**
+     * Sets a list of group members
+     *
+     * If this principal is a group, this method sets all the group members.
+     * The list of members is always overwritten, never appended to.
+     *
+     * This method should throw an exception if the members could not be set.
+     *
+     * @param array $principals
+     * @return void
+     */
+    function setGroupMemberSet(array $principals);
+
+    /**
+     * Returns the displayname
+     *
+     * This should be a human readable name for the principal.
+     * If none is available, return the nodename.
+     *
+     * @return string
+     */
+    function getDisplayName();
+
+}
diff --git a/vendor/sabre/dav/lib/DAVACL/IPrincipalCollection.php b/vendor/sabre/dav/lib/DAVACL/IPrincipalCollection.php
new file mode 100644
index 000000000..3ab8382fa
--- /dev/null
+++ b/vendor/sabre/dav/lib/DAVACL/IPrincipalCollection.php
@@ -0,0 +1,62 @@
+<?php
+
+namespace Sabre\DAVACL;
+
+use Sabre\DAV;
+
+/**
+ * Principal Collection interface.
+ *
+ * Implement this interface to ensure that your principal collection can be
+ * searched using the principal-property-search REPORT.
+ *
+ * @copyright Copyright (C) fruux GmbH (https://fruux.com/)
+ * @author Evert Pot (http://evertpot.com/)
+ * @license http://sabre.io/license/ Modified BSD License
+ */
+interface IPrincipalCollection extends DAV\ICollection {
+
+    /**
+     * This method is used to search for principals matching a set of
+     * properties.
+     *
+     * This search is specifically used by RFC3744's principal-property-search
+     * REPORT. You should at least allow searching on
+     * http://sabredav.org/ns}email-address.
+     *
+     * The actual search should be a unicode-non-case-sensitive search. The
+     * keys in searchProperties are the WebDAV property names, while the values
+     * are the property values to search on.
+     *
+     * By default, if multiple properties are submitted to this method, the
+     * various properties should be combined with 'AND'. If $test is set to
+     * 'anyof', it should be combined using 'OR'.
+     *
+     * This method should simply return a list of 'child names', which may be
+     * used to call $this->getChild in the future.
+     *
+     * @param array $searchProperties
+     * @param string $test
+     * @return array
+     */
+    function searchPrincipals(array $searchProperties, $test = 'allof');
+
+    /**
+     * Finds a principal by its URI.
+     *
+     * This method may receive any type of uri, but mailto: addresses will be
+     * the most common.
+     *
+     * Implementation of this API is optional. It is currently used by the
+     * CalDAV system to find principals based on their email addresses. If this
+     * API is not implemented, some features may not work correctly.
+     *
+     * This method must return a relative principal path, or null, if the
+     * principal was not found or you refuse to find it.
+     *
+     * @param string $uri
+     * @return string
+     */
+    function findByUri($uri);
+
+}
diff --git a/vendor/sabre/dav/lib/DAVACL/Plugin.php b/vendor/sabre/dav/lib/DAVACL/Plugin.php
new file mode 100644
index 000000000..601dffecc
--- /dev/null
+++ b/vendor/sabre/dav/lib/DAVACL/Plugin.php
@@ -0,0 +1,1323 @@
+<?php
+
+namespace Sabre\DAVACL;
+
+use Sabre\DAV;
+use Sabre\DAV\INode;
+use Sabre\DAV\Exception\BadRequest;
+use Sabre\HTTP\RequestInterface;
+use Sabre\HTTP\ResponseInterface;
+use Sabre\Uri;
+
+/**
+ * SabreDAV ACL Plugin
+ *
+ * This plugin provides functionality to enforce ACL permissions.
+ * ACL is defined in RFC3744.
+ *
+ * In addition it also provides support for the {DAV:}current-user-principal
+ * property, defined in RFC5397 and the {DAV:}expand-property report, as
+ * defined in RFC3253.
+ *
+ * @copyright Copyright (C) fruux GmbH (https://fruux.com/)
+ * @author Evert Pot (http://evertpot.com/)
+ * @license http://sabre.io/license/ Modified BSD License
+ */
+class Plugin extends DAV\ServerPlugin {
+
+    /**
+     * Recursion constants
+     *
+     * This only checks the base node
+     */
+    const R_PARENT = 1;
+
+    /**
+     * Recursion constants
+     *
+     * This checks every node in the tree
+     */
+    const R_RECURSIVE = 2;
+
+    /**
+     * Recursion constants
+     *
+     * This checks every parentnode in the tree, but not leaf-nodes.
+     */
+    const R_RECURSIVEPARENTS = 3;
+
+    /**
+     * Reference to server object.
+     *
+     * @var Sabre\DAV\Server
+     */
+    protected $server;
+
+    /**
+     * List of urls containing principal collections.
+     * Modify this if your principals are located elsewhere.
+     *
+     * @var array
+     */
+    public $principalCollectionSet = [
+        'principals',
+    ];
+
+    /**
+     * By default ACL is only enforced for nodes that have ACL support (the
+     * ones that implement IACL). For any other node, access is
+     * always granted.
+     *
+     * To override this behaviour you can turn this setting off. This is useful
+     * if you plan to fully support ACL in the entire tree.
+     *
+     * @var bool
+     */
+    public $allowAccessToNodesWithoutACL = true;
+
+    /**
+     * By default nodes that are inaccessible by the user, can still be seen
+     * in directory listings (PROPFIND on parent with Depth: 1)
+     *
+     * In certain cases it's desirable to hide inaccessible nodes. Setting this
+     * to true will cause these nodes to be hidden from directory listings.
+     *
+     * @var bool
+     */
+    public $hideNodesFromListings = false;
+
+    /**
+     * This list of properties are the properties a client can search on using
+     * the {DAV:}principal-property-search report.
+     *
+     * The keys are the property names, values are descriptions.
+     *
+     * @var array
+     */
+    public $principalSearchPropertySet = [
+        '{DAV:}displayname'                     => 'Display name',
+        '{http://sabredav.org/ns}email-address' => 'Email address',
+    ];
+
+    /**
+     * Any principal uri's added here, will automatically be added to the list
+     * of ACL's. They will effectively receive {DAV:}all privileges, as a
+     * protected privilege.
+     *
+     * @var array
+     */
+    public $adminPrincipals = [];
+
+    /**
+     * Returns a list of features added by this plugin.
+     *
+     * This list is used in the response of a HTTP OPTIONS request.
+     *
+     * @return array
+     */
+    function getFeatures() {
+
+        return ['access-control', 'calendarserver-principal-property-search'];
+
+    }
+
+    /**
+     * Returns a list of available methods for a given url
+     *
+     * @param string $uri
+     * @return array
+     */
+    function getMethods($uri) {
+
+        return ['ACL'];
+
+    }
+
+    /**
+     * Returns a plugin name.
+     *
+     * Using this name other plugins will be able to access other plugins
+     * using Sabre\DAV\Server::getPlugin
+     *
+     * @return string
+     */
+    function getPluginName() {
+
+        return 'acl';
+
+    }
+
+    /**
+     * Returns a list of reports this plugin supports.
+     *
+     * This will be used in the {DAV:}supported-report-set property.
+     * Note that you still need to subscribe to the 'report' event to actually
+     * implement them
+     *
+     * @param string $uri
+     * @return array
+     */
+    function getSupportedReportSet($uri) {
+
+        return [
+            '{DAV:}expand-property',
+            '{DAV:}principal-property-search',
+            '{DAV:}principal-search-property-set',
+        ];
+
+    }
+
+
+    /**
+     * Checks if the current user has the specified privilege(s).
+     *
+     * You can specify a single privilege, or a list of privileges.
+     * This method will throw an exception if the privilege is not available
+     * and return true otherwise.
+     *
+     * @param string $uri
+     * @param array|string $privileges
+     * @param int $recursion
+     * @param bool $throwExceptions if set to false, this method won't throw exceptions.
+     * @throws Sabre\DAVACL\Exception\NeedPrivileges
+     * @return bool
+     */
+    function checkPrivileges($uri, $privileges, $recursion = self::R_PARENT, $throwExceptions = true) {
+
+        if (!is_array($privileges)) $privileges = [$privileges];
+
+        $acl = $this->getCurrentUserPrivilegeSet($uri);
+
+        if (is_null($acl)) {
+            if ($this->allowAccessToNodesWithoutACL) {
+                return true;
+            } else {
+                if ($throwExceptions)
+                    throw new Exception\NeedPrivileges($uri, $privileges);
+                else
+                    return false;
+
+            }
+        }
+
+        $failed = [];
+        foreach ($privileges as $priv) {
+
+            if (!in_array($priv, $acl)) {
+                $failed[] = $priv;
+            }
+
+        }
+
+        if ($failed) {
+            if ($throwExceptions)
+                throw new Exception\NeedPrivileges($uri, $failed);
+            else
+                return false;
+        }
+        return true;
+
+    }
+
+    /**
+     * Returns the standard users' principal.
+     *
+     * This is one authorative principal url for the current user.
+     * This method will return null if the user wasn't logged in.
+     *
+     * @return string|null
+     */
+    function getCurrentUserPrincipal() {
+
+        $authPlugin = $this->server->getPlugin('auth');
+        if (is_null($authPlugin)) return null;
+        /** @var $authPlugin Sabre\DAV\Auth\Plugin */
+
+        return $authPlugin->getCurrentPrincipal();
+
+    }
+
+
+    /**
+     * Returns a list of principals that's associated to the current
+     * user, either directly or through group membership.
+     *
+     * @return array
+     */
+    function getCurrentUserPrincipals() {
+
+        $currentUser = $this->getCurrentUserPrincipal();
+
+        if (is_null($currentUser)) return [];
+
+        return array_merge(
+            [$currentUser],
+            $this->getPrincipalMembership($currentUser)
+        );
+
+    }
+
+    /**
+     * This array holds a cache for all the principals that are associated with
+     * a single principal.
+     *
+     * @var array
+     */
+    protected $principalMembershipCache = [];
+
+
+    /**
+     * Returns all the principal groups the specified principal is a member of.
+     *
+     * @param string $principal
+     * @return array
+     */
+    function getPrincipalMembership($mainPrincipal) {
+
+        // First check our cache
+        if (isset($this->principalMembershipCache[$mainPrincipal])) {
+            return $this->principalMembershipCache[$mainPrincipal];
+        }
+
+        $check = [$mainPrincipal];
+        $principals = [];
+
+        while (count($check)) {
+
+            $principal = array_shift($check);
+
+            $node = $this->server->tree->getNodeForPath($principal);
+            if ($node instanceof IPrincipal) {
+                foreach ($node->getGroupMembership() as $groupMember) {
+
+                    if (!in_array($groupMember, $principals)) {
+
+                        $check[] = $groupMember;
+                        $principals[] = $groupMember;
+
+                    }
+
+                }
+
+            }
+
+        }
+
+        // Store the result in the cache
+        $this->principalMembershipCache[$mainPrincipal] = $principals;
+
+        return $principals;
+
+    }
+
+    /**
+     * Returns the supported privilege structure for this ACL plugin.
+     *
+     * See RFC3744 for more details. Currently we default on a simple,
+     * standard structure.
+     *
+     * You can either get the list of privileges by a uri (path) or by
+     * specifying a Node.
+     *
+     * @param string|INode $node
+     * @return array
+     */
+    function getSupportedPrivilegeSet($node) {
+
+        if (is_string($node)) {
+            $node = $this->server->tree->getNodeForPath($node);
+        }
+
+        if ($node instanceof IACL) {
+            $result = $node->getSupportedPrivilegeSet();
+
+            if ($result)
+                return $result;
+        }
+
+        return self::getDefaultSupportedPrivilegeSet();
+
+    }
+
+    /**
+     * Returns a fairly standard set of privileges, which may be useful for
+     * other systems to use as a basis.
+     *
+     * @return array
+     */
+    static function getDefaultSupportedPrivilegeSet() {
+
+        return [
+            'privilege'  => '{DAV:}all',
+            'abstract'   => true,
+            'aggregates' => [
+                [
+                    'privilege'  => '{DAV:}read',
+                    'aggregates' => [
+                        [
+                            'privilege' => '{DAV:}read-acl',
+                            'abstract'  => false,
+                        ],
+                        [
+                            'privilege' => '{DAV:}read-current-user-privilege-set',
+                            'abstract'  => false,
+                        ],
+                    ],
+                ], // {DAV:}read
+                [
+                    'privilege'  => '{DAV:}write',
+                    'aggregates' => [
+                        [
+                            'privilege' => '{DAV:}write-acl',
+                            'abstract'  => false,
+                        ],
+                        [
+                            'privilege' => '{DAV:}write-properties',
+                            'abstract'  => false,
+                        ],
+                        [
+                            'privilege' => '{DAV:}write-content',
+                            'abstract'  => false,
+                        ],
+                        [
+                            'privilege' => '{DAV:}bind',
+                            'abstract'  => false,
+                        ],
+                        [
+                            'privilege' => '{DAV:}unbind',
+                            'abstract'  => false,
+                        ],
+                        [
+                            'privilege' => '{DAV:}unlock',
+                            'abstract'  => false,
+                        ],
+                    ],
+                ], // {DAV:}write
+            ],
+        ]; // {DAV:}all
+
+    }
+
+    /**
+     * Returns the supported privilege set as a flat list
+     *
+     * This is much easier to parse.
+     *
+     * The returned list will be index by privilege name.
+     * The value is a struct containing the following properties:
+     *   - aggregates
+     *   - abstract
+     *   - concrete
+     *
+     * @param string|INode $node
+     * @return array
+     */
+    final function getFlatPrivilegeSet($node) {
+
+        $privs = $this->getSupportedPrivilegeSet($node);
+
+        $fpsTraverse = null;
+        $fpsTraverse = function($priv, $concrete, &$flat) use (&$fpsTraverse) {
+
+            $myPriv = [
+                'privilege'  => $priv['privilege'],
+                'abstract'   => isset($priv['abstract']) && $priv['abstract'],
+                'aggregates' => [],
+                'concrete'   => isset($priv['abstract']) && $priv['abstract'] ? $concrete : $priv['privilege'],
+            ];
+
+            if (isset($priv['aggregates'])) {
+
+                foreach ($priv['aggregates'] as $subPriv) {
+
+                    $myPriv['aggregates'][] = $subPriv['privilege'];
+
+                }
+
+            }
+
+            $flat[$priv['privilege']] = $myPriv;
+
+            if (isset($priv['aggregates'])) {
+
+                foreach ($priv['aggregates'] as $subPriv) {
+
+                    $fpsTraverse($subPriv, $myPriv['concrete'], $flat);
+
+                }
+
+            }
+
+        };
+
+        $flat = [];
+        $fpsTraverse($privs, null, $flat);
+
+        return $flat;
+
+    }
+
+    /**
+     * Returns the full ACL list.
+     *
+     * Either a uri or a INode may be passed.
+     *
+     * null will be returned if the node doesn't support ACLs.
+     *
+     * @param string|DAV\INode $node
+     * @return array
+     */
+    function getACL($node) {
+
+        if (is_string($node)) {
+            $node = $this->server->tree->getNodeForPath($node);
+        }
+        if (!$node instanceof IACL) {
+            return null;
+        }
+        $acl = $node->getACL();
+        foreach ($this->adminPrincipals as $adminPrincipal) {
+            $acl[] = [
+                'principal' => $adminPrincipal,
+                'privilege' => '{DAV:}all',
+                'protected' => true,
+            ];
+        }
+        return $acl;
+
+    }
+
+    /**
+     * Returns a list of privileges the current user has
+     * on a particular node.
+     *
+     * Either a uri or a DAV\INode may be passed.
+     *
+     * null will be returned if the node doesn't support ACLs.
+     *
+     * @param string|DAV\INode $node
+     * @return array
+     */
+    function getCurrentUserPrivilegeSet($node) {
+
+        if (is_string($node)) {
+            $node = $this->server->tree->getNodeForPath($node);
+        }
+
+        $acl = $this->getACL($node);
+
+        if (is_null($acl)) return null;
+
+        $principals = $this->getCurrentUserPrincipals();
+
+        $collected = [];
+
+        foreach ($acl as $ace) {
+
+            $principal = $ace['principal'];
+
+            switch ($principal) {
+
+                case '{DAV:}owner' :
+                    $owner = $node->getOwner();
+                    if ($owner && in_array($owner, $principals)) {
+                        $collected[] = $ace;
+                    }
+                    break;
+
+
+                // 'all' matches for every user
+                case '{DAV:}all' :
+
+                // 'authenticated' matched for every user that's logged in.
+                // Since it's not possible to use ACL while not being logged
+                // in, this is also always true.
+                case '{DAV:}authenticated' :
+                    $collected[] = $ace;
+                    break;
+
+                // 'unauthenticated' can never occur either, so we simply
+                // ignore these.
+                case '{DAV:}unauthenticated' :
+                    break;
+
+                default :
+                    if (in_array($ace['principal'], $principals)) {
+                        $collected[] = $ace;
+                    }
+                    break;
+
+            }
+
+
+        }
+
+        // Now we deduct all aggregated privileges.
+        $flat = $this->getFlatPrivilegeSet($node);
+
+        $collected2 = [];
+        while (count($collected)) {
+
+            $current = array_pop($collected);
+            $collected2[] = $current['privilege'];
+
+            foreach ($flat[$current['privilege']]['aggregates'] as $subPriv) {
+                $collected2[] = $subPriv;
+                $collected[] = $flat[$subPriv];
+            }
+
+        }
+
+        return array_values(array_unique($collected2));
+
+    }
+
+
+    /**
+     * Returns a principal based on its uri.
+     *
+     * Returns null if the principal could not be found.
+     *
+     * @param string $uri
+     * @return null|string
+     */
+    function getPrincipalByUri($uri) {
+
+        $result = null;
+        $collections = $this->principalCollectionSet;
+        foreach ($collections as $collection) {
+
+            $principalCollection = $this->server->tree->getNodeForPath($collection);
+            if (!$principalCollection instanceof IPrincipalCollection) {
+                // Not a principal collection, we're simply going to ignore
+                // this.
+                continue;
+            }
+
+            $result = $principalCollection->findByUri($uri);
+            if ($result) {
+                return $result;
+            }
+
+        }
+
+    }
+
+    /**
+     * Principal property search
+     *
+     * This method can search for principals matching certain values in
+     * properties.
+     *
+     * This method will return a list of properties for the matched properties.
+     *
+     * @param array $searchProperties    The properties to search on. This is a
+     *                                   key-value list. The keys are property
+     *                                   names, and the values the strings to
+     *                                   match them on.
+     * @param array $requestedProperties This is the list of properties to
+     *                                   return for every match.
+     * @param string $collectionUri      The principal collection to search on.
+     *                                   If this is ommitted, the standard
+     *                                   principal collection-set will be used.
+     * @param string $test               "allof" to use AND to search the
+     *                                   properties. 'anyof' for OR.
+     * @return array     This method returns an array structure similar to
+     *                  Sabre\DAV\Server::getPropertiesForPath. Returned
+     *                  properties are index by a HTTP status code.
+     */
+    function principalSearch(array $searchProperties, array $requestedProperties, $collectionUri = null, $test = 'allof') {
+
+        if (!is_null($collectionUri)) {
+            $uris = [$collectionUri];
+        } else {
+            $uris = $this->principalCollectionSet;
+        }
+
+        $lookupResults = [];
+        foreach ($uris as $uri) {
+
+            $principalCollection = $this->server->tree->getNodeForPath($uri);
+            if (!$principalCollection instanceof IPrincipalCollection) {
+                // Not a principal collection, we're simply going to ignore
+                // this.
+                continue;
+            }
+
+            $results = $principalCollection->searchPrincipals($searchProperties, $test);
+            foreach ($results as $result) {
+                $lookupResults[] = rtrim($uri, '/') . '/' . $result;
+            }
+
+        }
+
+        $matches = [];
+
+        foreach ($lookupResults as $lookupResult) {
+
+            list($matches[]) = $this->server->getPropertiesForPath($lookupResult, $requestedProperties, 0);
+
+        }
+
+        return $matches;
+
+    }
+
+    /**
+     * Sets up the plugin
+     *
+     * This method is automatically called by the server class.
+     *
+     * @param DAV\Server $server
+     * @return void
+     */
+    function initialize(DAV\Server $server) {
+
+        $this->server = $server;
+        $server->on('propFind',            [$this, 'propFind'], 20);
+        $server->on('beforeMethod',        [$this, 'beforeMethod'], 20);
+        $server->on('beforeBind',          [$this, 'beforeBind'], 20);
+        $server->on('beforeUnbind',        [$this, 'beforeUnbind'], 20);
+        $server->on('propPatch',           [$this, 'propPatch']);
+        $server->on('beforeUnlock',        [$this, 'beforeUnlock'], 20);
+        $server->on('report',              [$this, 'report']);
+        $server->on('method:ACL',          [$this, 'httpAcl']);
+        $server->on('onHTMLActionsPanel',  [$this, 'htmlActionsPanel']);
+
+        array_push($server->protectedProperties,
+            '{DAV:}alternate-URI-set',
+            '{DAV:}principal-URL',
+            '{DAV:}group-membership',
+            '{DAV:}principal-collection-set',
+            '{DAV:}current-user-principal',
+            '{DAV:}supported-privilege-set',
+            '{DAV:}current-user-privilege-set',
+            '{DAV:}acl',
+            '{DAV:}acl-restrictions',
+            '{DAV:}inherited-acl-set',
+            '{DAV:}owner',
+            '{DAV:}group'
+        );
+
+        // Automatically mapping nodes implementing IPrincipal to the
+        // {DAV:}principal resourcetype.
+        $server->resourceTypeMapping['Sabre\\DAVACL\\IPrincipal'] = '{DAV:}principal';
+
+        // Mapping the group-member-set property to the HrefList property
+        // class.
+        $server->xml->elementMap['{DAV:}group-member-set'] = 'Sabre\\DAV\\Xml\\Property\\Href';
+        $server->xml->elementMap['{DAV:}acl'] = 'Sabre\\DAVACL\\Xml\\Property\\Acl';
+        $server->xml->elementMap['{DAV:}expand-property'] = 'Sabre\\DAVACL\\Xml\\Request\\ExpandPropertyReport';
+        $server->xml->elementMap['{DAV:}principal-property-search'] = 'Sabre\\DAVACL\\Xml\\Request\\PrincipalPropertySearchReport';
+        $server->xml->elementMap['{DAV:}principal-search-property-set'] = 'Sabre\\DAVACL\\Xml\\Request\\PrincipalSearchPropertySetReport';
+
+    }
+
+    /* {{{ Event handlers */
+
+    /**
+     * Triggered before any method is handled
+     *
+     * @param RequestInterface $request
+     * @param ResponseInterface $response
+     * @return void
+     */
+    function beforeMethod(RequestInterface $request, ResponseInterface $response) {
+
+        $method = $request->getMethod();
+        $path = $request->getPath();
+
+        $exists = $this->server->tree->nodeExists($path);
+
+        // If the node doesn't exists, none of these checks apply
+        if (!$exists) return;
+
+        switch ($method) {
+
+            case 'GET' :
+            case 'HEAD' :
+            case 'OPTIONS' :
+                // For these 3 we only need to know if the node is readable.
+                $this->checkPrivileges($path, '{DAV:}read');
+                break;
+
+            case 'PUT' :
+            case 'LOCK' :
+            case 'UNLOCK' :
+                // This method requires the write-content priv if the node
+                // already exists, and bind on the parent if the node is being
+                // created.
+                // The bind privilege is handled in the beforeBind event.
+                $this->checkPrivileges($path, '{DAV:}write-content');
+                break;
+
+
+            case 'PROPPATCH' :
+                $this->checkPrivileges($path, '{DAV:}write-properties');
+                break;
+
+            case 'ACL' :
+                $this->checkPrivileges($path, '{DAV:}write-acl');
+                break;
+
+            case 'COPY' :
+            case 'MOVE' :
+                // Copy requires read privileges on the entire source tree.
+                // If the target exists write-content normally needs to be
+                // checked, however, we're deleting the node beforehand and
+                // creating a new one after, so this is handled by the
+                // beforeUnbind event.
+                //
+                // The creation of the new node is handled by the beforeBind
+                // event.
+                //
+                // If MOVE is used beforeUnbind will also be used to check if
+                // the sourcenode can be deleted.
+                $this->checkPrivileges($path, '{DAV:}read', self::R_RECURSIVE);
+
+                break;
+
+        }
+
+    }
+
+    /**
+     * Triggered before a new node is created.
+     *
+     * This allows us to check permissions for any operation that creates a
+     * new node, such as PUT, MKCOL, MKCALENDAR, LOCK, COPY and MOVE.
+     *
+     * @param string $uri
+     * @return void
+     */
+    function beforeBind($uri) {
+
+        list($parentUri) = Uri\split($uri);
+        $this->checkPrivileges($parentUri, '{DAV:}bind');
+
+    }
+
+    /**
+     * Triggered before a node is deleted
+     *
+     * This allows us to check permissions for any operation that will delete
+     * an existing node.
+     *
+     * @param string $uri
+     * @return void
+     */
+    function beforeUnbind($uri) {
+
+        list($parentUri) = Uri\split($uri);
+        $this->checkPrivileges($parentUri, '{DAV:}unbind', self::R_RECURSIVEPARENTS);
+
+    }
+
+    /**
+     * Triggered before a node is unlocked.
+     *
+     * @param string $uri
+     * @param DAV\Locks\LockInfo $lock
+     * @TODO: not yet implemented
+     * @return void
+     */
+    function beforeUnlock($uri, DAV\Locks\LockInfo $lock) {
+
+
+    }
+
+    /**
+     * Triggered before properties are looked up in specific nodes.
+     *
+     * @param DAV\PropFind $propFind
+     * @param DAV\INode $node
+     * @param array $requestedProperties
+     * @param array $returnedProperties
+     * @TODO really should be broken into multiple methods, or even a class.
+     * @return bool
+     */
+    function propFind(DAV\PropFind $propFind, DAV\INode $node) {
+
+        $path = $propFind->getPath();
+
+        // Checking the read permission
+        if (!$this->checkPrivileges($path, '{DAV:}read', self::R_PARENT, false)) {
+            // User is not allowed to read properties
+
+            // Returning false causes the property-fetching system to pretend
+            // that the node does not exist, and will cause it to be hidden
+            // from listings such as PROPFIND or the browser plugin.
+            if ($this->hideNodesFromListings) {
+                return false;
+            }
+
+            // Otherwise we simply mark every property as 403.
+            foreach ($propFind->getRequestedProperties() as $requestedProperty) {
+                $propFind->set($requestedProperty, null, 403);
+            }
+
+            return;
+
+        }
+
+        /* Adding principal properties */
+        if ($node instanceof IPrincipal) {
+
+            $propFind->handle('{DAV:}alternate-URI-set', function() use ($node) {
+                return new DAV\Xml\Property\Href($node->getAlternateUriSet());
+            });
+            $propFind->handle('{DAV:}principal-URL', function() use ($node) {
+                return new DAV\Xml\Property\Href($node->getPrincipalUrl() . '/');
+            });
+            $propFind->handle('{DAV:}group-member-set', function() use ($node) {
+                $members = $node->getGroupMemberSet();
+                foreach ($members as $k => $member) {
+                    $members[$k] = rtrim($member, '/') . '/';
+                }
+                return new DAV\Xml\Property\Href($members);
+            });
+            $propFind->handle('{DAV:}group-membership', function() use ($node) {
+                $members = $node->getGroupMembership();
+                foreach ($members as $k => $member) {
+                    $members[$k] = rtrim($member, '/') . '/';
+                }
+                return new DAV\Xml\Property\Href($members);
+            });
+            $propFind->handle('{DAV:}displayname', [$node, 'getDisplayName']);
+
+        }
+
+        $propFind->handle('{DAV:}principal-collection-set', function() {
+
+            $val = $this->principalCollectionSet;
+            // Ensuring all collections end with a slash
+            foreach ($val as $k => $v) $val[$k] = $v . '/';
+            return new DAV\Xml\Property\Href($val);
+
+        });
+        $propFind->handle('{DAV:}current-user-principal', function() {
+            if ($url = $this->getCurrentUserPrincipal()) {
+                return new Xml\Property\Principal(Xml\Property\Principal::HREF, $url . '/');
+            } else {
+                return new Xml\Property\Principal(Xml\Property\Principal::UNAUTHENTICATED);
+            }
+        });
+        $propFind->handle('{DAV:}supported-privilege-set', function() use ($node) {
+            return new Xml\Property\SupportedPrivilegeSet($this->getSupportedPrivilegeSet($node));
+        });
+        $propFind->handle('{DAV:}current-user-privilege-set', function() use ($node, $propFind, $path) {
+            if (!$this->checkPrivileges($path, '{DAV:}read-current-user-privilege-set', self::R_PARENT, false)) {
+                $propFind->set('{DAV:}current-user-privilege-set', null, 403);
+            } else {
+                $val = $this->getCurrentUserPrivilegeSet($node);
+                if (!is_null($val)) {
+                    return new Xml\Property\CurrentUserPrivilegeSet($val);
+                }
+            }
+        });
+        $propFind->handle('{DAV:}acl', function() use ($node, $propFind, $path) {
+            /* The ACL property contains all the permissions */
+            if (!$this->checkPrivileges($path, '{DAV:}read-acl', self::R_PARENT, false)) {
+                $propFind->set('{DAV:}acl', null, 403);
+            } else {
+                $acl = $this->getACL($node);
+                if (!is_null($acl)) {
+                    return new Xml\Property\Acl($this->getACL($node));
+                }
+            }
+        });
+        $propFind->handle('{DAV:}acl-restrictions', function() {
+            return new Xml\Property\AclRestrictions();
+        });
+
+        /* Adding ACL properties */
+        if ($node instanceof IACL) {
+            $propFind->handle('{DAV:}owner', function() use ($node) {
+                return new DAV\Xml\Property\Href($node->getOwner() . '/');
+            });
+        }
+
+    }
+
+    /**
+     * This method intercepts PROPPATCH methods and make sure the
+     * group-member-set is updated correctly.
+     *
+     * @param string $path
+     * @param DAV\PropPatch $propPatch
+     * @return void
+     */
+    function propPatch($path, DAV\PropPatch $propPatch) {
+
+        $propPatch->handle('{DAV:}group-member-set', function($value) use ($path) {
+            if (is_null($value)) {
+                $memberSet = [];
+            } elseif ($value instanceof DAV\Xml\Property\Href) {
+                $memberSet = array_map(
+                    [$this->server, 'calculateUri'],
+                    $value->getHrefs()
+                );
+            } else {
+                throw new DAV\Exception('The group-member-set property MUST be an instance of Sabre\DAV\Property\HrefList or null');
+            }
+            $node = $this->server->tree->getNodeForPath($path);
+            if (!($node instanceof IPrincipal)) {
+                // Fail
+                return false;
+            }
+
+            $node->setGroupMemberSet($memberSet);
+            // We must also clear our cache, just in case
+
+            $this->principalMembershipCache = [];
+
+            return true;
+        });
+
+    }
+
+    /**
+     * This method handles HTTP REPORT requests
+     *
+     * @param string $reportName
+     * @param mixed $report
+     * @param mixed $path
+     * @return bool
+     */
+    function report($reportName, $report, $path) {
+
+        switch ($reportName) {
+
+            case '{DAV:}principal-property-search' :
+                $this->server->transactionType = 'report-principal-property-search';
+                $this->principalPropertySearchReport($report);
+                return false;
+            case '{DAV:}principal-search-property-set' :
+                $this->server->transactionType = 'report-principal-search-property-set';
+                $this->principalSearchPropertySetReport($report);
+                return false;
+            case '{DAV:}expand-property' :
+                $this->server->transactionType = 'report-expand-property';
+                $this->expandPropertyReport($report);
+                return false;
+
+        }
+
+    }
+
+    /**
+     * This method is responsible for handling the 'ACL' event.
+     *
+     * @param RequestInterface $request
+     * @param ResponseInterface $response
+     * @return bool
+     */
+    function httpAcl(RequestInterface $request, ResponseInterface $response) {
+
+        $path = $request->getPath();
+        $body = $request->getBodyAsString();
+
+        if (!$body) {
+            throw new DAV\Exception\BadRequest('XML body expected in ACL request');
+        }
+
+        $acl = $this->server->xml->expect('{DAV:}acl', $body);
+        $newAcl = $acl->getPrivileges();
+
+        // Normalizing urls
+        foreach ($newAcl as $k => $newAce) {
+            $newAcl[$k]['principal'] = $this->server->calculateUri($newAce['principal']);
+        }
+        $node = $this->server->tree->getNodeForPath($path);
+
+        if (!$node instanceof IACL) {
+            throw new DAV\Exception\MethodNotAllowed('This node does not support the ACL method');
+        }
+
+        $oldAcl = $this->getACL($node);
+
+        $supportedPrivileges = $this->getFlatPrivilegeSet($node);
+
+        /* Checking if protected principals from the existing principal set are
+           not overwritten. */
+        foreach ($oldAcl as $oldAce) {
+
+            if (!isset($oldAce['protected']) || !$oldAce['protected']) continue;
+
+            $found = false;
+            foreach ($newAcl as $newAce) {
+                if (
+                    $newAce['privilege'] === $oldAce['privilege'] &&
+                    $newAce['principal'] === $oldAce['principal'] &&
+                    $newAce['protected']
+                )
+                $found = true;
+            }
+
+            if (!$found)
+                throw new Exception\AceConflict('This resource contained a protected {DAV:}ace, but this privilege did not occur in the ACL request');
+
+        }
+
+        foreach ($newAcl as $newAce) {
+
+            // Do we recognize the privilege
+            if (!isset($supportedPrivileges[$newAce['privilege']])) {
+                throw new Exception\NotSupportedPrivilege('The privilege you specified (' . $newAce['privilege'] . ') is not recognized by this server');
+            }
+
+            if ($supportedPrivileges[$newAce['privilege']]['abstract']) {
+                throw new Exception\NoAbstract('The privilege you specified (' . $newAce['privilege'] . ') is an abstract privilege');
+            }
+
+            // Looking up the principal
+            try {
+                $principal = $this->server->tree->getNodeForPath($newAce['principal']);
+            } catch (DAV\Exception\NotFound $e) {
+                throw new Exception\NotRecognizedPrincipal('The specified principal (' . $newAce['principal'] . ') does not exist');
+            }
+            if (!($principal instanceof IPrincipal)) {
+                throw new Exception\NotRecognizedPrincipal('The specified uri (' . $newAce['principal'] . ') is not a principal');
+            }
+
+        }
+        $node->setACL($newAcl);
+
+        $response->setStatus(200);
+
+        // Breaking the event chain, because we handled this method.
+        return false;
+
+    }
+
+    /* }}} */
+
+    /* Reports {{{ */
+
+    /**
+     * The expand-property report is defined in RFC3253 section 3-8.
+     *
+     * This report is very similar to a standard PROPFIND. The difference is
+     * that it has the additional ability to look at properties containing a
+     * {DAV:}href element, follow that property and grab additional elements
+     * there.
+     *
+     * Other rfc's, such as ACL rely on this report, so it made sense to put
+     * it in this plugin.
+     *
+     * @param Xml\Request\ExpandPropertyReport $report
+     * @return void
+     */
+    protected function expandPropertyReport($report) {
+
+        $depth = $this->server->getHTTPDepth(0);
+        $requestUri = $this->server->getRequestUri();
+
+        $result = $this->expandProperties($requestUri, $report->properties, $depth);
+
+        $xml = $this->server->xml->write(
+            '{DAV:}multistatus',
+            new DAV\Xml\Response\MultiStatus($result),
+            $this->server->getBaseUri()
+        );
+        $this->server->httpResponse->setHeader('Content-Type', 'application/xml; charset=utf-8');
+        $this->server->httpResponse->setStatus(207);
+        $this->server->httpResponse->setBody($xml);
+
+    }
+
+    /**
+     * This method expands all the properties and returns
+     * a list with property values
+     *
+     * @param array $path
+     * @param array $requestedProperties the list of required properties
+     * @param int $depth
+     * @return array
+     */
+    protected function expandProperties($path, array $requestedProperties, $depth) {
+
+        $foundProperties = $this->server->getPropertiesForPath($path, array_keys($requestedProperties), $depth);
+
+        $result = [];
+
+        foreach ($foundProperties as $node) {
+
+            foreach ($requestedProperties as $propertyName => $childRequestedProperties) {
+
+                // We're only traversing if sub-properties were requested
+                if (count($childRequestedProperties) === 0) continue;
+
+                // We only have to do the expansion if the property was found
+                // and it contains an href element.
+                if (!array_key_exists($propertyName, $node[200])) continue;
+
+                if (!$node[200][$propertyName] instanceof DAV\Xml\Property\Href) {
+                    continue;
+                }
+
+                $childHrefs = $node[200][$propertyName]->getHrefs();
+                $childProps = [];
+
+                foreach ($childHrefs as $href) {
+                    // Gathering the result of the children
+                    $childProps[] = [
+                        'name'  => '{DAV:}response',
+                        'value' => $this->expandProperties($href, $childRequestedProperties, 0)[0]
+                    ];
+                }
+
+                // Replacing the property with its expannded form.
+                $node[200][$propertyName] = $childProps;
+
+            }
+            $result[] = new DAV\Xml\Element\Response($node['href'], $node);
+
+        }
+
+        return $result;
+
+    }
+
+    /**
+     * principalSearchPropertySetReport
+     *
+     * This method responsible for handing the
+     * {DAV:}principal-search-property-set report. This report returns a list
+     * of properties the client may search on, using the
+     * {DAV:}principal-property-search report.
+     *
+     * @param Xml\Request\PrincipalSearchPropertySetReport $report
+     * @return void
+     */
+    protected function principalSearchPropertySetReport($report) {
+
+        $httpDepth = $this->server->getHTTPDepth(0);
+        if ($httpDepth !== 0) {
+            throw new DAV\Exception\BadRequest('This report is only defined when Depth: 0');
+        }
+
+        $writer = $this->server->xml->getWriter();
+        $writer->openMemory();
+        $writer->startDocument();
+
+        $writer->startElement('{DAV:}principal-search-property-set');
+
+        foreach ($this->principalSearchPropertySet as $propertyName => $description) {
+
+            $writer->startElement('{DAV:}principal-search-property');
+            $writer->startElement('{DAV:}prop');
+
+            $writer->writeElement($propertyName);
+
+            $writer->endElement(); // prop
+
+            if ($description) {
+                $writer->write([[
+                    'name'       => '{DAV:}description',
+                    'value'      => $description,
+                    'attributes' => ['xml:lang' => 'en']
+                ]]);
+            }
+
+            $writer->endElement(); // principal-search-property
+
+
+        }
+
+        $writer->endElement(); // principal-search-property-set
+
+        $this->server->httpResponse->setHeader('Content-Type', 'application/xml; charset=utf-8');
+        $this->server->httpResponse->setStatus(200);
+        $this->server->httpResponse->setBody($writer->outputMemory());
+
+    }
+
+    /**
+     * principalPropertySearchReport
+     *
+     * This method is responsible for handing the
+     * {DAV:}principal-property-search report. This report can be used for
+     * clients to search for groups of principals, based on the value of one
+     * or more properties.
+     *
+     * @param Xml\Request\PrincipalPropertySearchReport $report
+     * @return void
+     */
+    protected function principalPropertySearchReport($report) {
+
+        $uri = null;
+        if (!$report->applyToPrincipalCollectionSet) {
+            $uri = $this->server->httpRequest->getPath();
+        }
+        if ($this->server->getHttpDepth('0') !== 0) {
+            throw new BadRequest('Depth must be 0');
+        }
+        $result = $this->principalSearch(
+            $report->searchProperties,
+            $report->properties,
+            $uri,
+            $report->test
+        );
+
+        $prefer = $this->server->getHTTPPrefer();
+
+        $this->server->httpResponse->setStatus(207);
+        $this->server->httpResponse->setHeader('Content-Type', 'application/xml; charset=utf-8');
+        $this->server->httpResponse->setHeader('Vary', 'Brief,Prefer');
+        $this->server->httpResponse->setBody($this->server->generateMultiStatus($result, $prefer['return'] === 'minimal'));
+
+    }
+
+    /* }}} */
+
+    /**
+     * This method is used to generate HTML output for the
+     * DAV\Browser\Plugin. This allows us to generate an interface users
+     * can use to create new calendars.
+     *
+     * @param DAV\INode $node
+     * @param string $output
+     * @return bool
+     */
+    function htmlActionsPanel(DAV\INode $node, &$output) {
+
+        if (!$node instanceof PrincipalCollection)
+            return;
+
+        $output .= '<tr><td colspan="2"><form method="post" action="">
+            <h3>Create new principal</h3>
+            <input type="hidden" name="sabreAction" value="mkcol" />
+            <input type="hidden" name="resourceType" value="{DAV:}principal" />
+            <label>Name (uri):</label> <input type="text" name="name" /><br />
+            <label>Display name:</label> <input type="text" name="{DAV:}displayname" /><br />
+            <label>Email address:</label> <input type="text" name="{http://sabredav*DOT*org/ns}email-address" /><br />
+            <input type="submit" value="create" />
+            </form>
+            </td></tr>';
+
+        return false;
+
+    }
+
+    /**
+     * Returns a bunch of meta-data about the plugin.
+     *
+     * Providing this information is optional, and is mainly displayed by the
+     * Browser plugin.
+     *
+     * The description key in the returned array may contain html and will not
+     * be sanitized.
+     *
+     * @return array
+     */
+    function getPluginInfo() {
+
+        return [
+            'name'        => $this->getPluginName(),
+            'description' => 'Adds support for WebDAV ACL (rfc3744)',
+            'link'        => 'http://sabre.io/dav/acl/',
+        ];
+
+    }
+}
diff --git a/vendor/sabre/dav/lib/DAVACL/Principal.php b/vendor/sabre/dav/lib/DAVACL/Principal.php
new file mode 100644
index 000000000..16375d3fc
--- /dev/null
+++ b/vendor/sabre/dav/lib/DAVACL/Principal.php
@@ -0,0 +1,288 @@
+<?php
+
+namespace Sabre\DAVACL;
+
+use Sabre\DAV;
+use Sabre\HTTP\URLUtil;
+
+/**
+ * Principal class
+ *
+ * This class is a representation of a simple principal
+ *
+ * Many WebDAV specs require a user to show up in the directory
+ * structure.
+ *
+ * This principal also has basic ACL settings, only allowing the principal
+ * access it's own principal.
+ *
+ * @copyright Copyright (C) fruux GmbH (https://fruux.com/)
+ * @author Evert Pot (http://evertpot.com/)
+ * @license http://sabre.io/license/ Modified BSD License
+ */
+class Principal extends DAV\Node implements IPrincipal, DAV\IProperties, IACL {
+
+    /**
+     * Struct with principal information.
+     *
+     * @var array
+     */
+    protected $principalProperties;
+
+    /**
+     * Principal backend
+     *
+     * @var PrincipalBackend\BackendInterface
+     */
+    protected $principalBackend;
+
+    /**
+     * Creates the principal object
+     *
+     * @param IPrincipalBackend $principalBackend
+     * @param array $principalProperties
+     */
+    function __construct(PrincipalBackend\BackendInterface $principalBackend, array $principalProperties = []) {
+
+        if (!isset($principalProperties['uri'])) {
+            throw new DAV\Exception('The principal properties must at least contain the \'uri\' key');
+        }
+        $this->principalBackend = $principalBackend;
+        $this->principalProperties = $principalProperties;
+
+    }
+
+    /**
+     * Returns the full principal url
+     *
+     * @return string
+     */
+    function getPrincipalUrl() {
+
+        return $this->principalProperties['uri'];
+
+    }
+
+    /**
+     * Returns a list of alternative urls for a principal
+     *
+     * This can for example be an email address, or ldap url.
+     *
+     * @return array
+     */
+    function getAlternateUriSet() {
+
+        $uris = [];
+        if (isset($this->principalProperties['{DAV:}alternate-URI-set'])) {
+
+            $uris = $this->principalProperties['{DAV:}alternate-URI-set'];
+
+        }
+
+        if (isset($this->principalProperties['{http://sabredav.org/ns}email-address'])) {
+            $uris[] = 'mailto:' . $this->principalProperties['{http://sabredav.org/ns}email-address'];
+        }
+
+        return array_unique($uris);
+
+    }
+
+    /**
+     * Returns the list of group members
+     *
+     * If this principal is a group, this function should return
+     * all member principal uri's for the group.
+     *
+     * @return array
+     */
+    function getGroupMemberSet() {
+
+        return $this->principalBackend->getGroupMemberSet($this->principalProperties['uri']);
+
+    }
+
+    /**
+     * Returns the list of groups this principal is member of
+     *
+     * If this principal is a member of a (list of) groups, this function
+     * should return a list of principal uri's for it's members.
+     *
+     * @return array
+     */
+    function getGroupMembership() {
+
+        return $this->principalBackend->getGroupMemberShip($this->principalProperties['uri']);
+
+    }
+
+    /**
+     * Sets a list of group members
+     *
+     * If this principal is a group, this method sets all the group members.
+     * The list of members is always overwritten, never appended to.
+     *
+     * This method should throw an exception if the members could not be set.
+     *
+     * @param array $groupMembers
+     * @return void
+     */
+    function setGroupMemberSet(array $groupMembers) {
+
+        $this->principalBackend->setGroupMemberSet($this->principalProperties['uri'], $groupMembers);
+
+    }
+
+    /**
+     * Returns this principals name.
+     *
+     * @return string
+     */
+    function getName() {
+
+        $uri = $this->principalProperties['uri'];
+        list(, $name) = URLUtil::splitPath($uri);
+        return $name;
+
+    }
+
+    /**
+     * Returns the name of the user
+     *
+     * @return string
+     */
+    function getDisplayName() {
+
+        if (isset($this->principalProperties['{DAV:}displayname'])) {
+            return $this->principalProperties['{DAV:}displayname'];
+        } else {
+            return $this->getName();
+        }
+
+    }
+
+    /**
+     * Returns a list of properties
+     *
+     * @param array $requestedProperties
+     * @return array
+     */
+    function getProperties($requestedProperties) {
+
+        $newProperties = [];
+        foreach ($requestedProperties as $propName) {
+
+            if (isset($this->principalProperties[$propName])) {
+                $newProperties[$propName] = $this->principalProperties[$propName];
+            }
+
+        }
+
+        return $newProperties;
+
+    }
+
+    /**
+     * Updates properties on this node.
+     *
+     * This method received a PropPatch object, which contains all the
+     * information about the update.
+     *
+     * To update specific properties, call the 'handle' method on this object.
+     * Read the PropPatch documentation for more information.
+     *
+     * @param DAV\PropPatch $propPatch
+     * @return void
+     */
+    function propPatch(DAV\PropPatch $propPatch) {
+
+        return $this->principalBackend->updatePrincipal(
+            $this->principalProperties['uri'],
+            $propPatch
+        );
+
+    }
+
+    /**
+     * Returns the owner principal
+     *
+     * This must be a url to a principal, or null if there's no owner
+     *
+     * @return string|null
+     */
+    function getOwner() {
+
+        return $this->principalProperties['uri'];
+
+
+    }
+
+    /**
+     * Returns a group principal
+     *
+     * This must be a url to a principal, or null if there's no owner
+     *
+     * @return string|null
+     */
+    function getGroup() {
+
+        return null;
+
+    }
+
+    /**
+     * Returns a list of ACE's for this node.
+     *
+     * Each ACE has the following properties:
+     *   * 'privilege', a string such as {DAV:}read or {DAV:}write. These are
+     *     currently the only supported privileges
+     *   * 'principal', a url to the principal who owns the node
+     *   * 'protected' (optional), indicating that this ACE is not allowed to
+     *      be updated.
+     *
+     * @return array
+     */
+    function getACL() {
+
+        return [
+            [
+                'privilege' => '{DAV:}read',
+                'principal' => '{DAV:}authenticated',
+                'protected' => true,
+            ],
+        ];
+
+    }
+
+    /**
+     * Updates the ACL
+     *
+     * This method will receive a list of new ACE's.
+     *
+     * @param array $acl
+     * @return void
+     */
+    function setACL(array $acl) {
+
+        throw new DAV\Exception\MethodNotAllowed('Updating ACLs is not allowed here');
+
+    }
+
+    /**
+     * Returns the list of supported privileges for this node.
+     *
+     * The returned data structure is a list of nested privileges.
+     * See Sabre\DAVACL\Plugin::getDefaultSupportedPrivilegeSet for a simple
+     * standard structure.
+     *
+     * If null is returned from this method, the default privilege set is used,
+     * which is fine for most common usecases.
+     *
+     * @return array|null
+     */
+    function getSupportedPrivilegeSet() {
+
+        return null;
+
+    }
+
+}
diff --git a/vendor/sabre/dav/lib/DAVACL/PrincipalBackend/AbstractBackend.php b/vendor/sabre/dav/lib/DAVACL/PrincipalBackend/AbstractBackend.php
new file mode 100644
index 000000000..9bf9ba445
--- /dev/null
+++ b/vendor/sabre/dav/lib/DAVACL/PrincipalBackend/AbstractBackend.php
@@ -0,0 +1,53 @@
+<?php
+
+namespace Sabre\DAVACL\PrincipalBackend;
+
+/**
+ * Abstract Principal Backend
+ *
+ * Currently this class has no function. It's here for consistency and so we
+ * have a non-bc-breaking way to add a default generic implementation to
+ * functions we may add in the future.
+ *
+ * @copyright Copyright (C) fruux GmbH (https://fruux.com/)
+ * @author Evert Pot (http://evertpot.com/)
+ * @license http://sabre.io/license/ Modified BSD License
+ */
+abstract class AbstractBackend implements BackendInterface {
+
+    /**
+     * Finds a principal by its URI.
+     *
+     * This method may receive any type of uri, but mailto: addresses will be
+     * the most common.
+     *
+     * Implementation of this API is optional. It is currently used by the
+     * CalDAV system to find principals based on their email addresses. If this
+     * API is not implemented, some features may not work correctly.
+     *
+     * This method must return a relative principal path, or null, if the
+     * principal was not found or you refuse to find it.
+     *
+     * @param string $uri
+     * @param string $principalPrefix
+     * @return string
+     */
+    function findByUri($uri, $principalPrefix) {
+
+        // Note that the default implementation here is a bit slow and could
+        // likely be optimized.
+        if (substr($uri, 0, 7) !== 'mailto:') {
+            return;
+        }
+        $result = $this->searchPrincipals(
+            $principalPrefix,
+            ['{http://sabredav.org/ns}email-address' => substr($uri, 7)]
+        );
+
+        if ($result) {
+            return $result[0];
+        }
+
+    }
+
+}
diff --git a/vendor/sabre/dav/lib/DAVACL/PrincipalBackend/BackendInterface.php b/vendor/sabre/dav/lib/DAVACL/PrincipalBackend/BackendInterface.php
new file mode 100644
index 000000000..2cb83071a
--- /dev/null
+++ b/vendor/sabre/dav/lib/DAVACL/PrincipalBackend/BackendInterface.php
@@ -0,0 +1,141 @@
+<?php
+
+namespace Sabre\DAVACL\PrincipalBackend;
+
+/**
+ * Implement this interface to create your own principal backends.
+ *
+ * Creating backends for principals is entirely optional. You can also
+ * implement Sabre\DAVACL\IPrincipal directly. This interface is used solely by
+ * Sabre\DAVACL\AbstractPrincipalCollection.
+ *
+ * @copyright Copyright (C) fruux GmbH (https://fruux.com/)
+ * @author Evert Pot (http://evertpot.com/)
+ * @license http://sabre.io/license/ Modified BSD License
+ */
+interface BackendInterface {
+
+    /**
+     * Returns a list of principals based on a prefix.
+     *
+     * This prefix will often contain something like 'principals'. You are only
+     * expected to return principals that are in this base path.
+     *
+     * You are expected to return at least a 'uri' for every user, you can
+     * return any additional properties if you wish so. Common properties are:
+     *   {DAV:}displayname
+     *   {http://sabredav.org/ns}email-address - This is a custom SabreDAV
+     *     field that's actually injected in a number of other properties. If
+     *     you have an email address, use this property.
+     *
+     * @param string $prefixPath
+     * @return array
+     */
+    function getPrincipalsByPrefix($prefixPath);
+
+    /**
+     * Returns a specific principal, specified by it's path.
+     * The returned structure should be the exact same as from
+     * getPrincipalsByPrefix.
+     *
+     * @param string $path
+     * @return array
+     */
+    function getPrincipalByPath($path);
+
+    /**
+     * Updates one ore more webdav properties on a principal.
+     *
+     * The list of mutations is stored in a Sabre\DAV\PropPatch object.
+     * To do the actual updates, you must tell this object which properties
+     * you're going to process with the handle() method.
+     *
+     * Calling the handle method is like telling the PropPatch object "I
+     * promise I can handle updating this property".
+     *
+     * Read the PropPatch documenation for more info and examples.
+     *
+     * @param string $path
+     * @param \Sabre\DAV\PropPatch $propPatch
+     * @return void
+     */
+    function updatePrincipal($path, \Sabre\DAV\PropPatch $propPatch);
+
+    /**
+     * This method is used to search for principals matching a set of
+     * properties.
+     *
+     * This search is specifically used by RFC3744's principal-property-search
+     * REPORT.
+     *
+     * The actual search should be a unicode-non-case-sensitive search. The
+     * keys in searchProperties are the WebDAV property names, while the values
+     * are the property values to search on.
+     *
+     * By default, if multiple properties are submitted to this method, the
+     * various properties should be combined with 'AND'. If $test is set to
+     * 'anyof', it should be combined using 'OR'.
+     *
+     * This method should simply return an array with full principal uri's.
+     *
+     * If somebody attempted to search on a property the backend does not
+     * support, you should simply return 0 results.
+     *
+     * You can also just return 0 results if you choose to not support
+     * searching at all, but keep in mind that this may stop certain features
+     * from working.
+     *
+     * @param string $prefixPath
+     * @param array $searchProperties
+     * @param string $test
+     * @return array
+     */
+    function searchPrincipals($prefixPath, array $searchProperties, $test = 'allof');
+
+    /**
+     * Finds a principal by its URI.
+     *
+     * This method may receive any type of uri, but mailto: addresses will be
+     * the most common.
+     *
+     * Implementation of this API is optional. It is currently used by the
+     * CalDAV system to find principals based on their email addresses. If this
+     * API is not implemented, some features may not work correctly.
+     *
+     * This method must return a relative principal path, or null, if the
+     * principal was not found or you refuse to find it.
+     *
+     * @param string $uri
+     * @param string $principalPrefix
+     * @return string
+     */
+    function findByUri($uri, $principalPrefix);
+
+    /**
+     * Returns the list of members for a group-principal
+     *
+     * @param string $principal
+     * @return array
+     */
+    function getGroupMemberSet($principal);
+
+    /**
+     * Returns the list of groups a principal is a member of
+     *
+     * @param string $principal
+     * @return array
+     */
+    function getGroupMembership($principal);
+
+    /**
+     * Updates the list of group members for a group principal.
+     *
+     * The principals should be passed as a list of uri's.
+     *
+     * @param string $principal
+     * @param array $members
+     * @return void
+     */
+    function setGroupMemberSet($principal, array $members);
+
+}
diff --git a/vendor/sabre/dav/lib/DAVACL/PrincipalBackend/CreatePrincipalSupport.php b/vendor/sabre/dav/lib/DAVACL/PrincipalBackend/CreatePrincipalSupport.php
new file mode 100644
index 000000000..e354a697d
--- /dev/null
+++ b/vendor/sabre/dav/lib/DAVACL/PrincipalBackend/CreatePrincipalSupport.php
@@ -0,0 +1,30 @@
+<?php
+
+namespace Sabre\DAVACL\PrincipalBackend;
+
+use Sabre\DAV\MkCol;
+
+/**
+ * Implement this interface to add support for creating new principals to your
+ * principal backend.
+ *
+ * @copyright Copyright (C) fruux GmbH (https://fruux.com/)
+ * @author Evert Pot (http://evertpot.com/)
+ * @license http://sabre.io/license/ Modified BSD License
+ */
+interface CreatePrincipalSupport extends BackendInterface {
+
+    /**
+     * Creates a new principal.
+     *
+     * This method receives a full path for the new principal. The mkCol object
+     * contains any additional webdav properties specified during the creation
+     * of the principal.
+     *
+     * @param string $path
+     * @param MkCol $mkCol
+     * @return void
+     */
+    function createPrincipal($path, MkCol $mkCol);
+
+}
diff --git a/vendor/sabre/dav/lib/DAVACL/PrincipalBackend/PDO.php b/vendor/sabre/dav/lib/DAVACL/PrincipalBackend/PDO.php
new file mode 100644
index 000000000..01b7a175c
--- /dev/null
+++ b/vendor/sabre/dav/lib/DAVACL/PrincipalBackend/PDO.php
@@ -0,0 +1,431 @@
+<?php
+
+namespace Sabre\DAVACL\PrincipalBackend;
+
+use Sabre\DAV;
+use Sabre\DAV\MkCol;
+use Sabre\HTTP\URLUtil;
+
+/**
+ * PDO principal backend
+ *
+ *
+ * This backend assumes all principals are in a single collection. The default collection
+ * is 'principals/', but this can be overriden.
+ *
+ * @copyright Copyright (C) fruux GmbH (https://fruux.com/)
+ * @author Evert Pot (http://evertpot.com/)
+ * @license http://sabre.io/license/ Modified BSD License
+ */
+class PDO extends AbstractBackend implements CreatePrincipalSupport {
+
+    /**
+     * PDO table name for 'principals'
+     *
+     * @var string
+     */
+    public $tableName = 'principals';
+
+    /**
+     * PDO table name for 'group members'
+     *
+     * @var string
+     */
+    public $groupMembersTableName = 'groupmembers';
+
+    /**
+     * pdo
+     *
+     * @var PDO
+     */
+    protected $pdo;
+
+    /**
+     * A list of additional fields to support
+     *
+     * @var array
+     */
+    protected $fieldMap = [
+
+        /**
+         * This property can be used to display the users' real name.
+         */
+        '{DAV:}displayname' => [
+            'dbField' => 'displayname',
+        ],
+
+        /**
+         * This is the users' primary email-address.
+         */
+        '{http://sabredav.org/ns}email-address' => [
+            'dbField' => 'email',
+        ],
+    ];
+
+    /**
+     * Sets up the backend.
+     *
+     * @param PDO $pdo
+     */
+    function __construct(\PDO $pdo) {
+
+        $this->pdo = $pdo;
+
+    }
+
+    /**
+     * Returns a list of principals based on a prefix.
+     *
+     * This prefix will often contain something like 'principals'. You are only
+     * expected to return principals that are in this base path.
+     *
+     * You are expected to return at least a 'uri' for every user, you can
+     * return any additional properties if you wish so. Common properties are:
+     *   {DAV:}displayname
+     *   {http://sabredav.org/ns}email-address - This is a custom SabreDAV
+     *     field that's actualy injected in a number of other properties. If
+     *     you have an email address, use this property.
+     *
+     * @param string $prefixPath
+     * @return array
+     */
+    function getPrincipalsByPrefix($prefixPath) {
+
+        $fields = [
+            'uri',
+        ];
+
+        foreach ($this->fieldMap as $key => $value) {
+            $fields[] = $value['dbField'];
+        }
+        $result = $this->pdo->query('SELECT ' . implode(',', $fields) . '  FROM ' . $this->tableName);
+
+        $principals = [];
+
+        while ($row = $result->fetch(\PDO::FETCH_ASSOC)) {
+
+            // Checking if the principal is in the prefix
+            list($rowPrefix) = URLUtil::splitPath($row['uri']);
+            if ($rowPrefix !== $prefixPath) continue;
+
+            $principal = [
+                'uri' => $row['uri'],
+            ];
+            foreach ($this->fieldMap as $key => $value) {
+                if ($row[$value['dbField']]) {
+                    $principal[$key] = $row[$value['dbField']];
+                }
+            }
+            $principals[] = $principal;
+
+        }
+
+        return $principals;
+
+    }
+
+    /**
+     * Returns a specific principal, specified by it's path.
+     * The returned structure should be the exact same as from
+     * getPrincipalsByPrefix.
+     *
+     * @param string $path
+     * @return array
+     */
+    function getPrincipalByPath($path) {
+
+        $fields = [
+            'id',
+            'uri',
+        ];
+
+        foreach ($this->fieldMap as $key => $value) {
+            $fields[] = $value['dbField'];
+        }
+        $stmt = $this->pdo->prepare('SELECT ' . implode(',', $fields) . '  FROM ' . $this->tableName . ' WHERE uri = ?');
+        $stmt->execute([$path]);
+
+        $row = $stmt->fetch(\PDO::FETCH_ASSOC);
+        if (!$row) return;
+
+        $principal = [
+            'id'  => $row['id'],
+            'uri' => $row['uri'],
+        ];
+        foreach ($this->fieldMap as $key => $value) {
+            if ($row[$value['dbField']]) {
+                $principal[$key] = $row[$value['dbField']];
+            }
+        }
+        return $principal;
+
+    }
+
+    /**
+     * Updates one ore more webdav properties on a principal.
+     *
+     * The list of mutations is stored in a Sabre\DAV\PropPatch object.
+     * To do the actual updates, you must tell this object which properties
+     * you're going to process with the handle() method.
+     *
+     * Calling the handle method is like telling the PropPatch object "I
+     * promise I can handle updating this property".
+     *
+     * Read the PropPatch documenation for more info and examples.
+     *
+     * @param string $path
+     * @param DAV\PropPatch $propPatch
+     */
+    function updatePrincipal($path, DAV\PropPatch $propPatch) {
+
+        $propPatch->handle(array_keys($this->fieldMap), function($properties) use ($path) {
+
+            $query = "UPDATE " . $this->tableName . " SET ";
+            $first = true;
+
+            $values = [];
+
+            foreach ($properties as $key => $value) {
+
+                $dbField = $this->fieldMap[$key]['dbField'];
+
+                if (!$first) {
+                    $query .= ', ';
+                }
+                $first = false;
+                $query .= $dbField . ' = :' . $dbField;
+                $values[$dbField] = $value;
+
+            }
+
+            $query .= " WHERE uri = :uri";
+            $values['uri'] = $path;
+
+            $stmt = $this->pdo->prepare($query);
+            $stmt->execute($values);
+
+            return true;
+
+        });
+
+    }
+
+    /**
+     * This method is used to search for principals matching a set of
+     * properties.
+     *
+     * This search is specifically used by RFC3744's principal-property-search
+     * REPORT.
+     *
+     * The actual search should be a unicode-non-case-sensitive search. The
+     * keys in searchProperties are the WebDAV property names, while the values
+     * are the property values to search on.
+     *
+     * By default, if multiple properties are submitted to this method, the
+     * various properties should be combined with 'AND'. If $test is set to
+     * 'anyof', it should be combined using 'OR'.
+     *
+     * This method should simply return an array with full principal uri's.
+     *
+     * If somebody attempted to search on a property the backend does not
+     * support, you should simply return 0 results.
+     *
+     * You can also just return 0 results if you choose to not support
+     * searching at all, but keep in mind that this may stop certain features
+     * from working.
+     *
+     * @param string $prefixPath
+     * @param array $searchProperties
+     * @param string $test
+     * @return array
+     */
+    function searchPrincipals($prefixPath, array $searchProperties, $test = 'allof') {
+        if (count($searchProperties) == 0) return [];    //No criteria
+
+        $query = 'SELECT uri FROM ' . $this->tableName . ' WHERE ';
+        $values = [];
+        foreach ($searchProperties as $property => $value) {
+            switch ($property) {
+                case '{DAV:}displayname' :
+                    $column = "displayname";
+                    break;
+                case '{http://sabredav.org/ns}email-address' :
+                    $column = "email";
+                    break;
+                default :
+                    // Unsupported property
+                    return [];
+            }
+            if (count($values) > 0) $query .= (strcmp($test, "anyof") == 0 ? " OR " : " AND ");
+            $query .= 'lower(' . $column . ') LIKE lower(?)';
+            $values[] = '%' . $value . '%';
+
+        }
+        $stmt = $this->pdo->prepare($query);
+        $stmt->execute($values);
+
+        $principals = [];
+        while ($row = $stmt->fetch(\PDO::FETCH_ASSOC)) {
+
+            // Checking if the principal is in the prefix
+            list($rowPrefix) = URLUtil::splitPath($row['uri']);
+            if ($rowPrefix !== $prefixPath) continue;
+
+            $principals[] = $row['uri'];
+
+        }
+
+        return $principals;
+
+    }
+
+    /**
+     * Finds a principal by its URI.
+     *
+     * This method may receive any type of uri, but mailto: addresses will be
+     * the most common.
+     *
+     * Implementation of this API is optional. It is currently used by the
+     * CalDAV system to find principals based on their email addresses. If this
+     * API is not implemented, some features may not work correctly.
+     *
+     * This method must return a relative principal path, or null, if the
+     * principal was not found or you refuse to find it.
+     *
+     * @param string $uri
+     * @param string $principalPrefix
+     * @return string
+     */
+    function findByUri($uri, $principalPrefix) {
+        $value = null;
+        $scheme = null;
+        list($scheme, $value) = explode(":", $uri, 2);
+        if ($value == null) return null;
+
+        $uri = null;
+        switch ($scheme){
+            case "mailto":
+                $query = 'SELECT uri FROM ' . $this->tableName . ' WHERE lower(email)=lower(?)';
+                $stmt = $this->pdo->prepare($query);
+                $stmt->execute([ $value ]);
+            
+                while ($row = $stmt->fetch(\PDO::FETCH_ASSOC)) {
+                    // Checking if the principal is in the prefix
+                    list($rowPrefix) = URLUtil::splitPath($row['uri']);
+                    if ($rowPrefix !== $principalPrefix) continue;
+                    
+                    $uri = $row['uri'];
+                    break; //Stop on first match
+                }
+                break;
+            default:
+                //unsupported uri scheme
+                return null;
+        }
+        return $uri;
+    }
+
+    /**
+     * Returns the list of members for a group-principal
+     *
+     * @param string $principal
+     * @return array
+     */
+    function getGroupMemberSet($principal) {
+
+        $principal = $this->getPrincipalByPath($principal);
+        if (!$principal) throw new DAV\Exception('Principal not found');
+
+        $stmt = $this->pdo->prepare('SELECT principals.uri as uri FROM ' . $this->groupMembersTableName . ' AS groupmembers LEFT JOIN ' . $this->tableName . ' AS principals ON groupmembers.member_id = principals.id WHERE groupmembers.principal_id = ?');
+        $stmt->execute([$principal['id']]);
+
+        $result = [];
+        while ($row = $stmt->fetch(\PDO::FETCH_ASSOC)) {
+            $result[] = $row['uri'];
+        }
+        return $result;
+
+    }
+
+    /**
+     * Returns the list of groups a principal is a member of
+     *
+     * @param string $principal
+     * @return array
+     */
+    function getGroupMembership($principal) {
+
+        $principal = $this->getPrincipalByPath($principal);
+        if (!$principal) throw new DAV\Exception('Principal not found');
+
+        $stmt = $this->pdo->prepare('SELECT principals.uri as uri FROM ' . $this->groupMembersTableName . ' AS groupmembers LEFT JOIN ' . $this->tableName . ' AS principals ON groupmembers.principal_id = principals.id WHERE groupmembers.member_id = ?');
+        $stmt->execute([$principal['id']]);
+
+        $result = [];
+        while ($row = $stmt->fetch(\PDO::FETCH_ASSOC)) {
+            $result[] = $row['uri'];
+        }
+        return $result;
+
+    }
+
+    /**
+     * Updates the list of group members for a group principal.
+     *
+     * The principals should be passed as a list of uri's.
+     *
+     * @param string $principal
+     * @param array $members
+     * @return void
+     */
+    function setGroupMemberSet($principal, array $members) {
+
+        // Grabbing the list of principal id's.
+        $stmt = $this->pdo->prepare('SELECT id, uri FROM ' . $this->tableName . ' WHERE uri IN (? ' . str_repeat(', ? ', count($members)) . ');');
+        $stmt->execute(array_merge([$principal], $members));
+
+        $memberIds = [];
+        $principalId = null;
+
+        while ($row = $stmt->fetch(\PDO::FETCH_ASSOC)) {
+            if ($row['uri'] == $principal) {
+                $principalId = $row['id'];
+            } else {
+                $memberIds[] = $row['id'];
+            }
+        }
+        if (!$principalId) throw new DAV\Exception('Principal not found');
+
+        // Wiping out old members
+        $stmt = $this->pdo->prepare('DELETE FROM ' . $this->groupMembersTableName . ' WHERE principal_id = ?;');
+        $stmt->execute([$principalId]);
+
+        foreach ($memberIds as $memberId) {
+
+            $stmt = $this->pdo->prepare('INSERT INTO ' . $this->groupMembersTableName . ' (principal_id, member_id) VALUES (?, ?);');
+            $stmt->execute([$principalId, $memberId]);
+
+        }
+
+    }
+
+    /**
+     * Creates a new principal.
+     *
+     * This method receives a full path for the new principal. The mkCol object
+     * contains any additional webdav properties specified during the creation
+     * of the principal.
+     *
+     * @param string $path
+     * @param MkCol $mkCol
+     * @return void
+     */
+    function createPrincipal($path, MkCol $mkCol) {
+
+        $stmt = $this->pdo->prepare('INSERT INTO ' . $this->tableName . ' (uri) VALUES (?)');
+        $stmt->execute([$path]);
+        $this->updatePrincipal($path, $mkCol);
+
+    }
+
+}
diff --git a/vendor/sabre/dav/lib/DAVACL/PrincipalCollection.php b/vendor/sabre/dav/lib/DAVACL/PrincipalCollection.php
new file mode 100644
index 000000000..54911e7b5
--- /dev/null
+++ b/vendor/sabre/dav/lib/DAVACL/PrincipalCollection.php
@@ -0,0 +1,151 @@
+<?php
+
+namespace Sabre\DAVACL;
+
+use Sabre\DAV\Exception\InvalidResourceType;
+use Sabre\DAV\Exception\Forbidden;
+use Sabre\DAV\IExtendedCollection;
+use Sabre\DAV\MkCol;
+
+/**
+ * Principals Collection
+ *
+ * This collection represents a list of users.
+ * The users are instances of Sabre\DAVACL\Principal
+ *
+ * @copyright Copyright (C) fruux GmbH (https://fruux.com/)
+ * @author Evert Pot (http://evertpot.com/)
+ * @license http://sabre.io/license/ Modified BSD License
+ */
+class PrincipalCollection extends AbstractPrincipalCollection implements IExtendedCollection, IACL {
+
+    /**
+     * This method returns a node for a principal.
+     *
+     * The passed array contains principal information, and is guaranteed to
+     * at least contain a uri item. Other properties may or may not be
+     * supplied by the authentication backend.
+     *
+     * @param array $principal
+     * @return \Sabre\DAV\INode
+     */
+    function getChildForPrincipal(array $principal) {
+
+        return new Principal($this->principalBackend, $principal);
+
+    }
+
+    /**
+     * Creates a new collection.
+     *
+     * This method will receive a MkCol object with all the information about
+     * the new collection that's being created.
+     *
+     * The MkCol object contains information about the resourceType of the new
+     * collection. If you don't support the specified resourceType, you should
+     * throw Exception\InvalidResourceType.
+     *
+     * The object also contains a list of WebDAV properties for the new
+     * collection.
+     *
+     * You should call the handle() method on this object to specify exactly
+     * which properties you are storing. This allows the system to figure out
+     * exactly which properties you didn't store, which in turn allows other
+     * plugins (such as the propertystorage plugin) to handle storing the
+     * property for you.
+     *
+     * @param string $name
+     * @param MkCol $mkCol
+     * @throws Exception\InvalidResourceType
+     * @return void
+     */
+    function createExtendedCollection($name, MkCol $mkCol) {
+
+        if (!$mkCol->hasResourceType('{DAV:}principal')) {
+            throw new InvalidResourceType('Only resources of type {DAV:}principal may be created here');
+        }
+
+        $this->principalBackend->createPrincipal(
+            $this->principalPrefix . '/' . $name,
+            $mkCol
+        );
+
+    }
+
+    /**
+     * Returns the owner principal
+     *
+     * This must be a url to a principal, or null if there's no owner
+     *
+     * @return string|null
+     */
+    function getOwner() {
+        return null;
+    }
+
+    /**
+     * Returns a group principal
+     *
+     * This must be a url to a principal, or null if there's no owner
+     *
+     * @return string|null
+     */
+    function getGroup() {
+        return null;
+    }
+
+    /**
+     * Returns a list of ACE's for this node.
+     *
+     * Each ACE has the following properties:
+     *   * 'privilege', a string such as {DAV:}read or {DAV:}write. These are
+     *     currently the only supported privileges
+     *   * 'principal', a url to the principal who owns the node
+     *   * 'protected' (optional), indicating that this ACE is not allowed to
+     *      be updated.
+     *
+     * @return array
+     */
+    function getACL() {
+        return [
+            [
+                'principal' => '{DAV:}authenticated',
+                'privilege' => '{DAV:}read',
+                'protected' => true,
+            ],
+        ];
+    }
+
+    /**
+     * Updates the ACL
+     *
+     * This method will receive a list of new ACE's as an array argument.
+     *
+     * @param array $acl
+     * @return void
+     */
+    function setACL(array $acl) {
+
+        throw new Forbidden('Updating ACLs is not allowed on this node');
+
+    }
+
+    /**
+     * Returns the list of supported privileges for this node.
+     *
+     * The returned data structure is a list of nested privileges.
+     * See Sabre\DAVACL\Plugin::getDefaultSupportedPrivilegeSet for a simple
+     * standard structure.
+     *
+     * If null is returned from this method, the default privilege set is used,
+     * which is fine for most common usecases.
+     *
+     * @return array|null
+     */
+    function getSupportedPrivilegeSet() {
+
+        return null;
+
+    }
+
+}
diff --git a/vendor/sabre/dav/lib/DAVACL/Xml/Property/Acl.php b/vendor/sabre/dav/lib/DAVACL/Xml/Property/Acl.php
new file mode 100644
index 000000000..9f5e40df1
--- /dev/null
+++ b/vendor/sabre/dav/lib/DAVACL/Xml/Property/Acl.php
@@ -0,0 +1,277 @@
+<?php
+
+namespace Sabre\DAVACL\Xml\Property;
+
+use Sabre\DAV;
+use Sabre\DAV\Browser\HtmlOutput;
+use Sabre\DAV\Browser\HtmlOutputHelper;
+use Sabre\Xml\Element;
+use Sabre\Xml\Reader;
+use Sabre\Xml\Writer;
+
+/**
+ * This class represents the {DAV:}acl property.
+ *
+ * The {DAV:}acl property is a full list of access control entries for a
+ * resource.
+ *
+ * {DAV:}acl is used as a WebDAV property, but it is also used within the body
+ * of the ACL request.
+ *
+ * See:
+ * http://tools.ietf.org/html/rfc3744#section-5.5
+ *
+ * @copyright Copyright (C) fruux GmbH (https://fruux.com/)
+ * @author Evert Pot (http://evertpot.com/)
+ * @license http://sabre.io/license/ Modified BSD License
+ */
+class Acl implements Element, HtmlOutput {
+
+    /**
+     * List of privileges
+     *
+     * @var array
+     */
+    protected $privileges;
+
+    /**
+     * Whether or not the server base url is required to be prefixed when
+     * serializing the property.
+     *
+     * @var bool
+     */
+    protected $prefixBaseUrl;
+
+    /**
+     * Constructor
+     *
+     * This object requires a structure similar to the return value from
+     * Sabre\DAVACL\Plugin::getACL().
+     *
+     * Each privilege is a an array with at least a 'privilege' property, and a
+     * 'principal' property. A privilege may have a 'protected' property as
+     * well.
+     *
+     * The prefixBaseUrl should be set to false, if the supplied principal urls
+     * are already full urls. If this is kept to true, the servers base url
+     * will automatically be prefixed.
+     *
+     * @param array $privileges
+     * @param bool $prefixBaseUrl
+     */
+    function __construct(array $privileges, $prefixBaseUrl = true) {
+
+        $this->privileges = $privileges;
+        $this->prefixBaseUrl = $prefixBaseUrl;
+
+    }
+
+    /**
+     * Returns the list of privileges for this property
+     *
+     * @return array
+     */
+    function getPrivileges() {
+
+        return $this->privileges;
+
+    }
+
+    /**
+     * The xmlSerialize metod is called during xml writing.
+     *
+     * Use the $writer argument to write its own xml serialization.
+     *
+     * An important note: do _not_ create a parent element. Any element
+     * implementing XmlSerializble should only ever write what's considered
+     * its 'inner xml'.
+     *
+     * The parent of the current element is responsible for writing a
+     * containing element.
+     *
+     * This allows serializers to be re-used for different element names.
+     *
+     * If you are opening new elements, you must also close them again.
+     *
+     * @param Writer $writer
+     * @return void
+     */
+    function xmlSerialize(Writer $writer) {
+
+        foreach ($this->privileges as $ace) {
+
+            $this->serializeAce($writer, $ace);
+
+        }
+
+    }
+
+    /**
+     * Generate html representation for this value.
+     *
+     * The html output is 100% trusted, and no effort is being made to sanitize
+     * it. It's up to the implementor to sanitize user provided values.
+     *
+     * The output must be in UTF-8.
+     *
+     * The baseUri parameter is a url to the root of the application, and can
+     * be used to construct local links.
+     *
+     * @param HtmlOutputHelper $html
+     * @return string
+     */
+    function toHtml(HtmlOutputHelper $html) {
+
+        ob_start();
+        echo "<table>";
+        echo "<tr><th>Principal</th><th>Privilege</th><th></th></tr>";
+        foreach ($this->privileges as $privilege) {
+
+            echo '<tr>';
+            // if it starts with a {, it's a special principal
+            if ($privilege['principal'][0] === '{') {
+                echo '<td>', $html->xmlName($privilege['principal']), '</td>';
+            } else {
+                echo '<td>', $html->link($privilege['principal']), '</td>';
+            }
+            echo '<td>', $html->xmlName($privilege['privilege']), '</td>';
+            echo '<td>';
+            if (!empty($privilege['protected'])) echo '(protected)';
+            echo '</td>';
+            echo '</tr>';
+
+        }
+        echo "</table>";
+        return ob_get_clean();
+
+    }
+
+    /**
+     * The deserialize method is called during xml parsing.
+     *
+     * This method is called statictly, this is because in theory this method
+     * may be used as a type of constructor, or factory method.
+     *
+     * Often you want to return an instance of the current class, but you are
+     * free to return other data as well.
+     *
+     * Important note 2: You are responsible for advancing the reader to the
+     * next element. Not doing anything will result in a never-ending loop.
+     *
+     * If you just want to skip parsing for this element altogether, you can
+     * just call $reader->next();
+     *
+     * $reader->parseInnerTree() will parse the entire sub-tree, and advance to
+     * the next element.
+     *
+     * @param Reader $reader
+     * @return mixed
+     */
+    static function xmlDeserialize(Reader $reader) {
+
+        $elementMap = [
+            '{DAV:}ace'       => 'Sabre\Xml\Element\KeyValue',
+            '{DAV:}privilege' => 'Sabre\Xml\Element\Elements',
+            '{DAV:}principal' => 'Sabre\DAVACL\Xml\Property\Principal',
+        ];
+
+        $privileges = [];
+
+        foreach ((array)$reader->parseInnerTree($elementMap) as $element) {
+
+            if ($element['name'] !== '{DAV:}ace') {
+                continue;
+            }
+            $ace = $element['value'];
+
+            if (empty($ace['{DAV:}principal'])) {
+                throw new DAV\Exception\BadRequest('Each {DAV:}ace element must have one {DAV:}principal element');
+            }
+            $principal = $ace['{DAV:}principal'];
+
+            switch ($principal->getType()) {
+                case Principal::HREF :
+                    $principal = $principal->getHref();
+                    break;
+                case Principal::AUTHENTICATED :
+                    $principal = '{DAV:}authenticated';
+                    break;
+                case Principal::UNAUTHENTICATED :
+                    $principal = '{DAV:}unauthenticated';
+                    break;
+                case Principal::ALL :
+                    $principal = '{DAV:}all';
+                    break;
+
+            }
+
+            $protected = array_key_exists('{DAV:}protected', $ace);
+
+            if (!isset($ace['{DAV:}grant'])) {
+                throw new DAV\Exception\NotImplemented('Every {DAV:}ace element must have a {DAV:}grant element. {DAV:}deny is not yet supported');
+            }
+            foreach ($ace['{DAV:}grant'] as $elem) {
+                if ($elem['name'] !== '{DAV:}privilege') {
+                    continue;
+                }
+
+                foreach ($elem['value'] as $priv) {
+                    $privileges[] = [
+                        'principal' => $principal,
+                        'protected' => $protected,
+                        'privilege' => $priv,
+                    ];
+                }
+
+            }
+
+        }
+
+        return new self($privileges);
+
+    }
+
+    /**
+     * Serializes a single access control entry.
+     *
+     * @param Writer $writer
+     * @param array $ace
+     * @return void
+     */
+    private function serializeAce(Writer $writer, array $ace) {
+
+        $writer->startElement('{DAV:}ace');
+
+        switch ($ace['principal']) {
+            case '{DAV:}authenticated' :
+                $principal = new Principal(Principal::AUTHENTICATED);
+                break;
+            case '{DAV:}unauthenticated' :
+                $principal = new Principal(Principal::UNAUTHENTICATED);
+                break;
+            case '{DAV:}all' :
+                $principal = new Principal(Principal::ALL);
+                break;
+            default:
+                $principal = new Principal(Principal::HREF, $ace['principal']);
+                break;
+        }
+
+        $writer->writeElement('{DAV:}principal', $principal);
+        $writer->startElement('{DAV:}grant');
+        $writer->startElement('{DAV:}privilege');
+
+        $writer->writeElement($ace['privilege']);
+
+        $writer->endElement(); // privilege
+        $writer->endElement(); // grant
+
+        if (!empty($ace['protected'])) {
+            $writer->writeElement('{DAV:}protected');
+        }
+
+        $writer->endElement(); // ace
+
+    }
+
+}
diff --git a/vendor/sabre/dav/lib/DAVACL/Xml/Property/AclRestrictions.php b/vendor/sabre/dav/lib/DAVACL/Xml/Property/AclRestrictions.php
new file mode 100644
index 000000000..f669cc5e1
--- /dev/null
+++ b/vendor/sabre/dav/lib/DAVACL/Xml/Property/AclRestrictions.php
@@ -0,0 +1,45 @@
+<?php
+
+namespace Sabre\DAVACL\Xml\Property;
+
+use Sabre\Xml\XmlSerializable;
+use Sabre\Xml\Writer;
+
+/**
+ * AclRestrictions property
+ *
+ * This property represents {DAV:}acl-restrictions, as defined in RFC3744.
+ *
+ * @copyright Copyright (C) fruux GmbH (https://fruux.com/)
+ * @author Evert Pot (http://evertpot.com/)
+ * @license http://sabre.io/license/ Modified BSD License
+ */
+class AclRestrictions implements XmlSerializable {
+
+    /**
+     * The xmlSerialize metod is called during xml writing.
+     *
+     * Use the $writer argument to write its own xml serialization.
+     *
+     * An important note: do _not_ create a parent element. Any element
+     * implementing XmlSerializble should only ever write what's considered
+     * its 'inner xml'.
+     *
+     * The parent of the current element is responsible for writing a
+     * containing element.
+     *
+     * This allows serializers to be re-used for different element names.
+     *
+     * If you are opening new elements, you must also close them again.
+     *
+     * @param Writer $writer
+     * @return void
+     */
+    function xmlSerialize(Writer $writer) {
+
+        $writer->writeElement('{DAV:}grant-only');
+        $writer->writeElement('{DAV:}no-invert');
+
+    }
+
+}
diff --git a/vendor/sabre/dav/lib/DAVACL/Xml/Property/CurrentUserPrivilegeSet.php b/vendor/sabre/dav/lib/DAVACL/Xml/Property/CurrentUserPrivilegeSet.php
new file mode 100644
index 000000000..0a95eb2b7
--- /dev/null
+++ b/vendor/sabre/dav/lib/DAVACL/Xml/Property/CurrentUserPrivilegeSet.php
@@ -0,0 +1,159 @@
+<?php
+
+namespace Sabre\DAVACL\Xml\Property;
+
+use Sabre\DAV\Browser\HtmlOutput;
+use Sabre\DAV\Browser\HtmlOutputHelper;
+use Sabre\Xml\Element;
+use Sabre\Xml\Reader;
+use Sabre\Xml\Writer;
+
+/**
+ * CurrentUserPrivilegeSet
+ *
+ * This class represents the current-user-privilege-set property. When
+ * requested, it contain all the privileges a user has on a specific node.
+ *
+ * @copyright Copyright (C) fruux GmbH (https://fruux.com/)
+ * @author Evert Pot (http://evertpot.com/)
+ * @license http://sabre.io/license/ Modified BSD License
+ */
+class CurrentUserPrivilegeSet implements Element, HtmlOutput {
+
+    /**
+     * List of privileges
+     *
+     * @var array
+     */
+    private $privileges;
+
+    /**
+     * Creates the object
+     *
+     * Pass the privileges in clark-notation
+     *
+     * @param array $privileges
+     */
+    function __construct(array $privileges) {
+
+        $this->privileges = $privileges;
+
+    }
+
+    /**
+     * The xmlSerialize metod is called during xml writing.
+     *
+     * Use the $writer argument to write its own xml serialization.
+     *
+     * An important note: do _not_ create a parent element. Any element
+     * implementing XmlSerializble should only ever write what's considered
+     * its 'inner xml'.
+     *
+     * The parent of the current element is responsible for writing a
+     * containing element.
+     *
+     * This allows serializers to be re-used for different element names.
+     *
+     * If you are opening new elements, you must also close them again.
+     *
+     * @param Writer $writer
+     * @return void
+     */
+    function xmlSerialize(Writer $writer) {
+
+        foreach ($this->privileges as $privName) {
+
+            $writer->startElement('{DAV:}privilege');
+            $writer->writeElement($privName);
+            $writer->endElement();
+
+        }
+
+
+    }
+
+    /**
+     * Returns true or false, whether the specified principal appears in the
+     * list.
+     *
+     * @param string $privilegeName
+     * @return bool
+     */
+    function has($privilegeName) {
+
+        return in_array($privilegeName, $this->privileges);
+
+    }
+
+    /**
+     * Returns the list of privileges.
+     *
+     * @return array
+     */
+    function getValue() {
+
+        return $this->privileges;
+
+    }
+
+    /**
+     * The deserialize method is called during xml parsing.
+     *
+     * This method is called statictly, this is because in theory this method
+     * may be used as a type of constructor, or factory method.
+     *
+     * Often you want to return an instance of the current class, but you are
+     * free to return other data as well.
+     *
+     * You are responsible for advancing the reader to the next element. Not
+     * doing anything will result in a never-ending loop.
+     *
+     * If you just want to skip parsing for this element altogether, you can
+     * just call $reader->next();
+     *
+     * $reader->parseInnerTree() will parse the entire sub-tree, and advance to
+     * the next element.
+     *
+     * @param Reader $reader
+     * @return mixed
+     */
+    static function xmlDeserialize(Reader $reader) {
+
+        $result = [];
+
+        $tree = $reader->parseInnerTree(['{DAV:}privilege' => 'Sabre\\Xml\\Element\\Elements']);
+        foreach ($tree as $element) {
+            if ($element['name'] !== '{DAV:}privilege') {
+                continue;
+            }
+            $result[] = $element['value'][0];
+        }
+        return new self($result);
+
+    }
+
+    /**
+     * Generate html representation for this value.
+     *
+     * The html output is 100% trusted, and no effort is being made to sanitize
+     * it. It's up to the implementor to sanitize user provided values.
+     *
+     * The output must be in UTF-8.
+     *
+     * The baseUri parameter is a url to the root of the application, and can
+     * be used to construct local links.
+     *
+     * @param HtmlOutputHelper $html
+     * @return string
+     */
+    function toHtml(HtmlOutputHelper $html) {
+
+        return implode(
+            ', ',
+            array_map([$html, 'xmlName'], $this->getValue())
+        );
+
+    }
+
+
+}
diff --git a/vendor/sabre/dav/lib/DAVACL/Xml/Property/Principal.php b/vendor/sabre/dav/lib/DAVACL/Xml/Property/Principal.php
new file mode 100644
index 000000000..d32249d8b
--- /dev/null
+++ b/vendor/sabre/dav/lib/DAVACL/Xml/Property/Principal.php
@@ -0,0 +1,196 @@
+<?php
+
+namespace Sabre\DAVACL\Xml\Property;
+
+use Sabre\DAV;
+use Sabre\DAV\Browser\HtmlOutputHelper;
+use Sabre\DAV\Exception\BadRequest;
+use Sabre\Xml\Reader;
+use Sabre\Xml\Writer;
+
+/**
+ * Principal property
+ *
+ * The principal property represents a principal from RFC3744 (ACL).
+ * The property can be used to specify a principal or pseudo principals.
+ *
+ * @copyright Copyright (C) fruux GmbH (https://fruux.com/)
+ * @author Evert Pot (http://evertpot.com/)
+ * @license http://sabre.io/license/ Modified BSD License
+ */
+class Principal extends DAV\Xml\Property\Href {
+
+    /**
+     * To specify a not-logged-in user, use the UNAUTHENTICATED principal
+     */
+    const UNAUTHENTICATED = 1;
+
+    /**
+     * To specify any principal that is logged in, use AUTHENTICATED
+     */
+    const AUTHENTICATED = 2;
+
+    /**
+     * Specific principals can be specified with the HREF
+     */
+    const HREF = 3;
+
+    /**
+     * Everybody, basically
+     */
+    const ALL = 4;
+
+    /**
+     * Principal-type
+     *
+     * Must be one of the UNAUTHENTICATED, AUTHENTICATED or HREF constants.
+     *
+     * @var int
+     */
+    protected $type;
+
+    /**
+     * Creates the property.
+     *
+     * The 'type' argument must be one of the type constants defined in this class.
+     *
+     * 'href' is only required for the HREF type.
+     *
+     * @param int $type
+     * @param string|null $href
+     */
+    function __construct($type, $href = null) {
+
+        $this->type = $type;
+        if ($type === self::HREF && is_null($href)) {
+            throw new DAV\Exception('The href argument must be specified for the HREF principal type.');
+        }
+        if ($href) {
+            $href = rtrim($href, '/') . '/';
+            parent::__construct($href);
+        }
+
+    }
+
+    /**
+     * Returns the principal type
+     *
+     * @return int
+     */
+    function getType() {
+
+        return $this->type;
+
+    }
+
+
+    /**
+     * The xmlSerialize metod is called during xml writing.
+     *
+     * Use the $writer argument to write its own xml serialization.
+     *
+     * An important note: do _not_ create a parent element. Any element
+     * implementing XmlSerializble should only ever write what's considered
+     * its 'inner xml'.
+     *
+     * The parent of the current element is responsible for writing a
+     * containing element.
+     *
+     * This allows serializers to be re-used for different element names.
+     *
+     * If you are opening new elements, you must also close them again.
+     *
+     * @param Writer $writer
+     * @return void
+     */
+    function xmlSerialize(Writer $writer) {
+
+        switch ($this->type) {
+
+            case self::UNAUTHENTICATED :
+                $writer->writeElement('{DAV:}unauthenticated');
+                break;
+            case self::AUTHENTICATED :
+                $writer->writeElement('{DAV:}authenticated');
+                break;
+            case self::HREF :
+                parent::xmlSerialize($writer);
+                break;
+            case self::ALL :
+                $writer->writeElement('{DAV:}all');
+                break;
+        }
+
+    }
+
+    /**
+     * Generate html representation for this value.
+     *
+     * The html output is 100% trusted, and no effort is being made to sanitize
+     * it. It's up to the implementor to sanitize user provided values.
+     *
+     * The output must be in UTF-8.
+     *
+     * The baseUri parameter is a url to the root of the application, and can
+     * be used to construct local links.
+     *
+     * @param HtmlOutputHelper $html
+     * @return string
+     */
+    function toHtml(HtmlOutputHelper $html) {
+
+        switch ($this->type) {
+
+            case self::UNAUTHENTICATED :
+                return '<em>unauthenticated</em>';
+            case self::AUTHENTICATED :
+                return '<em>authenticated</em>';
+            case self::HREF :
+                return parent::toHtml($html);
+            case self::ALL :
+                return '<em>all</em>';
+        }
+
+    }
+
+    /**
+     * The deserialize method is called during xml parsing.
+     *
+     * This method is called staticly, this is because in theory this method
+     * may be used as a type of constructor, or factory method.
+     *
+     * Often you want to return an instance of the current class, but you are
+     * free to return other data as well.
+     *
+     * Important note 2: You are responsible for advancing the reader to the
+     * next element. Not doing anything will result in a never-ending loop.
+     *
+     * If you just want to skip parsing for this element altogether, you can
+     * just call $reader->next();
+     *
+     * $reader->parseInnerTree() will parse the entire sub-tree, and advance to
+     * the next element.
+     *
+     * @param Reader $reader
+     * @return mixed
+     */
+    static function xmlDeserialize(Reader $reader) {
+
+        $tree = $reader->parseInnerTree()[0];
+
+        switch ($tree['name']) {
+            case '{DAV:}unauthenticated' :
+                return new self(self::UNAUTHENTICATED);
+            case '{DAV:}authenticated' :
+                return new self(self::AUTHENTICATED);
+            case '{DAV:}href':
+                return new self(self::HREF, $tree['value']);
+            case '{DAV:}all':
+                return new self(self::ALL);
+            default :
+                throw new BadRequest('Unknown or unsupported principal type: ' . $tree['name']);
+        }
+
+    }
+
+}
diff --git a/vendor/sabre/dav/lib/DAVACL/Xml/Property/SupportedPrivilegeSet.php b/vendor/sabre/dav/lib/DAVACL/Xml/Property/SupportedPrivilegeSet.php
new file mode 100644
index 000000000..572bed4dd
--- /dev/null
+++ b/vendor/sabre/dav/lib/DAVACL/Xml/Property/SupportedPrivilegeSet.php
@@ -0,0 +1,159 @@
+<?php
+
+namespace Sabre\DAVACL\Xml\Property;
+
+use Sabre\DAV\Browser\HtmlOutput;
+use Sabre\DAV\Browser\HtmlOutputHelper;
+use Sabre\Xml\XmlSerializable;
+use Sabre\Xml\Writer;
+
+/**
+ * SupportedPrivilegeSet property
+ *
+ * This property encodes the {DAV:}supported-privilege-set property, as defined
+ * in rfc3744. Please consult the rfc for details about it's structure.
+ *
+ * This class expects a structure like the one given from
+ * Sabre\DAVACL\Plugin::getSupportedPrivilegeSet as the argument in its
+ * constructor.
+ *
+ * @copyright Copyright (C) fruux GmbH (https://fruux.com/)
+ * @author Evert Pot (http://evertpot.com/)
+ * @license http://sabre.io/license/ Modified BSD License
+ */
+class SupportedPrivilegeSet implements XmlSerializable, HtmlOutput {
+
+    /**
+     * privileges
+     *
+     * @var array
+     */
+    protected $privileges;
+
+    /**
+     * Constructor
+     *
+     * @param array $privileges
+     */
+    function __construct(array $privileges) {
+
+        $this->privileges = $privileges;
+
+    }
+
+    /**
+     * Returns the privilege value.
+     *
+     * @return array
+     */
+    function getValue() {
+
+        return $this->privileges;
+
+    }
+
+    /**
+     * The xmlSerialize metod is called during xml writing.
+     *
+     * Use the $writer argument to write its own xml serialization.
+     *
+     * An important note: do _not_ create a parent element. Any element
+     * implementing XmlSerializble should only ever write what's considered
+     * its 'inner xml'.
+     *
+     * The parent of the current element is responsible for writing a
+     * containing element.
+     *
+     * This allows serializers to be re-used for different element names.
+     *
+     * If you are opening new elements, you must also close them again.
+     *
+     * @param Writer $writer
+     * @return void
+     */
+    function xmlSerialize(Writer $writer) {
+
+        $this->serializePriv($writer, $this->privileges);
+
+    }
+
+    /**
+     * Generate html representation for this value.
+     *
+     * The html output is 100% trusted, and no effort is being made to sanitize
+     * it. It's up to the implementor to sanitize user provided values.
+     *
+     * The output must be in UTF-8.
+     *
+     * The baseUri parameter is a url to the root of the application, and can
+     * be used to construct local links.
+     *
+     * @param HtmlOutputHelper $html
+     * @return string
+     */
+    function toHtml(HtmlOutputHelper $html) {
+
+        $traverse = function($priv) use (&$traverse, $html) {
+            echo "<li>";
+            echo $html->xmlName($priv['privilege']);
+            if (isset($priv['abstract']) && $priv['abstract']) {
+                echo " <i>(abstract)</i>";
+            }
+            if (isset($priv['description'])) {
+                echo " " . $html->h($priv['description']);
+            }
+            if (isset($priv['aggregates'])) {
+                echo "\n<ul>\n";
+                foreach ($priv['aggregates'] as $subPriv) {
+                    $traverse($subPriv);
+                }
+                echo "</ul>";
+            }
+            echo "</li>\n";
+        };
+
+        ob_start();
+        echo "<ul class=\"tree\">";
+        $traverse($this->getValue());
+        echo "</ul>\n";
+
+        return ob_get_clean();
+
+    }
+
+
+
+    /**
+     * Serializes a property
+     *
+     * This is a recursive function.
+     *
+     * @param Writer $writer
+     * @param array $privilege
+     * @return void
+     */
+    private function serializePriv(Writer $writer, $privilege) {
+
+        $writer->startElement('{DAV:}supported-privilege');
+
+        $writer->startElement('{DAV:}privilege');
+        $writer->writeElement($privilege['privilege']);
+        $writer->endElement(); // privilege
+
+        if (!empty($privilege['abstract'])) {
+            $writer->writeElement('{DAV:}abstract');
+        }
+        if (!empty($privilege['description'])) {
+            $writer->writeElement('{DAV:}description', $privilege['description']);
+        }
+        if (isset($privilege['aggregates'])) {
+            foreach ($privilege['aggregates'] as $subPrivilege) {
+                $this->serializePriv($writer, $subPrivilege);
+            }
+        }
+
+        $writer->endElement(); // supported-privilege
+
+    }
+
+}
diff --git a/vendor/sabre/dav/lib/DAVACL/Xml/Request/ExpandPropertyReport.php b/vendor/sabre/dav/lib/DAVACL/Xml/Request/ExpandPropertyReport.php
new file mode 100644
index 000000000..3f535e301
--- /dev/null
+++ b/vendor/sabre/dav/lib/DAVACL/Xml/Request/ExpandPropertyReport.php
@@ -0,0 +1,103 @@
+<?php
+
+namespace Sabre\DAVACL\Xml\Request;
+
+use Sabre\Xml\Reader;
+use Sabre\Xml\XmlDeserializable;
+
+/**
+ * ExpandProperty request parser.
+ *
+ * This class parses the {DAV:}expand-property REPORT, as defined in:
+ *
+ * http://tools.ietf.org/html/rfc3253#section-3.8
+ *
+ * @copyright Copyright (C) fruux GmbH (https://fruux.com/)
+ * @author Evert Pot (http://evertpot.com/)
+ * @license http://sabre.io/license/ Modified BSD License
+ */
+class ExpandPropertyReport implements XmlDeserializable {
+
+    /**
+     * An array with requested properties.
+     *
+     * The requested properties will be used as keys in this array. The value
+     * is normally null.
+     *
+     * If the value is an array though, it means the property must be expanded.
+     * Within the array, the sub-properties, which themselves may be null or
+     * arrays.
+     *
+     * @var array
+     */
+    public $properties;
+
+    /**
+     * The deserialize method is called during xml parsing.
+     *
+     * This method is called statictly, this is because in theory this method
+     * may be used as a type of constructor, or factory method.
+     *
+     * Often you want to return an instance of the current class, but you are
+     * free to return other data as well.
+     *
+     * You are responsible for advancing the reader to the next element. Not
+     * doing anything will result in a never-ending loop.
+     *
+     * If you just want to skip parsing for this element altogether, you can
+     * just call $reader->next();
+     *
+     * $reader->parseInnerTree() will parse the entire sub-tree, and advance to
+     * the next element.
+     *
+     * @param Reader $reader
+     * @return mixed
+     */
+    static function xmlDeserialize(Reader $reader) {
+
+        $elems = $reader->parseInnerTree();
+
+        $obj = new self();
+        $obj->properties = self::traverse($elems);
+
+        return $obj;
+
+    }
+
+    /**
+     * This method is used by deserializeXml, to recursively parse the
+     * {DAV:}property elements.
+     *
+     * @param array $elems
+     * @return void
+     */
+    private static function traverse($elems) {
+
+        $result = [];
+
+        foreach ($elems as $elem) {
+
+            if ($elem['name'] !== '{DAV:}property') {
+                continue;
+            }
+
+            $namespace = isset($elem['attributes']['namespace']) ?
+                $elem['attributes']['namespace'] :
+                'DAV:';
+
+            $propName = '{' . $namespace . '}' . $elem['attributes']['name'];
+
+            $value = null;
+            if (is_array($elem['value'])) {
+                $value = self::traverse($elem['value']);
+            }
+
+            $result[$propName] = $value;
+
+        }
+
+        return $result;
+
+    }
+
+}
diff --git a/vendor/sabre/dav/lib/DAVACL/Xml/Request/PrincipalPropertySearchReport.php b/vendor/sabre/dav/lib/DAVACL/Xml/Request/PrincipalPropertySearchReport.php
new file mode 100644
index 000000000..1e7aa4481
--- /dev/null
+++ b/vendor/sabre/dav/lib/DAVACL/Xml/Request/PrincipalPropertySearchReport.php
@@ -0,0 +1,127 @@
+<?php
+
+namespace Sabre\DAVACL\Xml\Request;
+
+use Sabre\Xml\Reader;
+use Sabre\Xml\XmlDeserializable;
+use Sabre\DAV\Exception\BadRequest;
+
+/**
+ * PrincipalSearchPropertySetReport request parser.
+ *
+ * This class parses the {DAV:}principal-property-search REPORT, as defined
+ * in:
+ *
+ * https://tools.ietf.org/html/rfc3744#section-9.4
+ *
+ * @copyright Copyright (C) fruux GmbH (https://fruux.com/)
+ * @author Evert Pot (http://evertpot.com/)
+ * @license http://sabre.io/license/ Modified BSD License
+ */
+class PrincipalPropertySearchReport implements XmlDeserializable {
+
+    /**
+     * The requested properties.
+     *
+     * @var array|null
+     */
+    public $properties;
+
+    /**
+     * searchProperties
+     *
+     * @var array
+     */
+    public $searchProperties = [];
+
+    /**
+     * By default the property search will be conducted on the url of the http
+     * request. If this is set to true, it will be applied to the principal
+     * collection set instead.
+     *
+     * @var bool
+     */
+    public $applyToPrincipalCollectionSet = false;
+
+    /**
+     * Search for principals matching ANY of the properties (OR) or a ALL of
+     * the properties (AND).
+     *
+     * This property is either "anyof" or "allof".
+     *
+     * @var string
+     */
+    public $test;
+
+    /**
+     * The deserialize method is called during xml parsing.
+     *
+     * This method is called statictly, this is because in theory this method
+     * may be used as a type of constructor, or factory method.
+     *
+     * Often you want to return an instance of the current class, but you are
+     * free to return other data as well.
+     *
+     * You are responsible for advancing the reader to the next element. Not
+     * doing anything will result in a never-ending loop.
+     *
+     * If you just want to skip parsing for this element altogether, you can
+     * just call $reader->next();
+     *
+     * $reader->parseInnerTree() will parse the entire sub-tree, and advance to
+     * the next element.
+     *
+     * @param Reader $reader
+     * @return mixed
+     */
+    static function xmlDeserialize(Reader $reader) {
+
+        $self = new self();
+
+        $foundSearchProp = false;
+        $self->test = 'allof';
+        if ($reader->getAttribute('test') === 'anyof') {
+            $self->test = 'anyof';
+        }
+
+        $elemMap = [
+            '{DAV:}property-search' => 'Sabre\\Xml\\Element\\KeyValue',
+            '{DAV:}prop'            => 'Sabre\\Xml\\Element\\KeyValue',
+        ];
+        
+        foreach ($reader->parseInnerTree($elemMap) as $elem) {
+
+            switch ($elem['name']) {
+
+                case '{DAV:}prop' :
+                    $self->properties = array_keys($elem['value']);
+                    break;
+                case '{DAV:}property-search' :
+                    $foundSearchProp = true;
+                    // This property has two sub-elements:
+                    //   {DAV:}prop - The property to be searched on. This may
+                    //                also be more than one
+                    //   {DAV:}match - The value to match with
+                    if (!isset($elem['value']['{DAV:}prop']) || !isset($elem['value']['{DAV:}match'])) {
+                        throw new BadRequest('The {DAV:}property-search element must contain one {DAV:}match and one {DAV:}prop element');
+                    }
+                    foreach ($elem['value']['{DAV:}prop'] as $propName => $discard) {
+                        $self->searchProperties[$propName] = $elem['value']['{DAV:}match'];
+                    }
+                    break;
+                case '{DAV:}apply-to-principal-collection-set' :
+                    $self->applyToPrincipalCollectionSet = true;
+                    break;
+
+            }
+
+        }
+        if (!$foundSearchProp) {
+            throw new BadRequest('The {DAV:}principal-property-search report must contain at least 1 {DAV:}property-search element');
+        }
+
+        return $self;
+
+    }
+
+}
diff --git a/vendor/sabre/dav/lib/DAVACL/Xml/Request/PrincipalSearchPropertySetReport.php b/vendor/sabre/dav/lib/DAVACL/Xml/Request/PrincipalSearchPropertySetReport.php
new file mode 100644
index 000000000..ade157b19
--- /dev/null
+++ b/vendor/sabre/dav/lib/DAVACL/Xml/Request/PrincipalSearchPropertySetReport.php
@@ -0,0 +1,58 @@
+<?php
+
+namespace Sabre\DAVACL\Xml\Request;
+
+use Sabre\Xml\Reader;
+use Sabre\Xml\XmlDeserializable;
+use Sabre\DAV\Exception\BadRequest;
+
+/**
+ * PrincipalSearchPropertySetReport request parser.
+ *
+ * This class parses the {DAV:}principal-search-property-set REPORT, as defined
+ * in:
+ *
+ * https://tools.ietf.org/html/rfc3744#section-9.5
+ *
+ * @copyright Copyright (C) fruux GmbH (https://fruux.com/)
+ * @author Evert Pot (http://evertpot.com/)
+ * @license http://sabre.io/license/ Modified BSD License
+ */
+class PrincipalSearchPropertySetReport implements XmlDeserializable {
+
+    /**
+     * The deserialize method is called during xml parsing.
+     *
+     * This method is called statictly, this is because in theory this method
+     * may be used as a type of constructor, or factory method.
+     *
+     * Often you want to return an instance of the current class, but you are
+     * free to return other data as well.
+     *
+     * You are responsible for advancing the reader to the next element. Not
+     * doing anything will result in a never-ending loop.
+     *
+     * If you just want to skip parsing for this element altogether, you can
+     * just call $reader->next();
+     *
+     * $reader->parseInnerTree() will parse the entire sub-tree, and advance to
+     * the next element.
+     *
+     * @param Reader $reader
+     * @return mixed
+     */
+    static function xmlDeserialize(Reader $reader) {
+
+        if (!$reader->isEmptyElement) {
+            throw new BadRequest('The {DAV:}principal-search-property-set element must be empty');
+        }
+
+        // The element is actually empty, so there's not much to do.
+        $reader->next();
+
+        $self = new self();
+        return $self;
+
+    }
+
+}