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

20 files changed, 3651 insertions, 0 deletions

diff --git a/vendor/sabre/dav/lib/CardDAV/AddressBook.php b/vendor/sabre/dav/lib/CardDAV/AddressBook.php
new file mode 100644
index 000000000..70bec8760
--- /dev/null
+++ b/vendor/sabre/dav/lib/CardDAV/AddressBook.php
@@ -0,0 +1,433 @@
+<?php
+
+namespace Sabre\CardDAV;
+
+use Sabre\DAV;
+use Sabre\DAVACL;
+
+/**
+ * The AddressBook class represents a CardDAV addressbook, owned by a specific user
+ *
+ * The AddressBook can contain multiple vcards
+ *
+ * @copyright Copyright (C) fruux GmbH (https://fruux.com/)
+ * @author Evert Pot (http://evertpot.com/)
+ * @license http://sabre.io/license/ Modified BSD License
+ */
+class AddressBook extends DAV\Collection implements IAddressBook, DAV\IProperties, DAVACL\IACL, DAV\Sync\ISyncCollection, DAV\IMultiGet {
+
+    /**
+     * This is an array with addressbook information
+     *
+     * @var array
+     */
+    protected $addressBookInfo;
+
+    /**
+     * CardDAV backend
+     *
+     * @var Backend\BackendInterface
+     */
+    protected $carddavBackend;
+
+    /**
+     * Constructor
+     *
+     * @param Backend\BackendInterface $carddavBackend
+     * @param array $addressBookInfo
+     */
+    function __construct(Backend\BackendInterface $carddavBackend, array $addressBookInfo) {
+
+        $this->carddavBackend = $carddavBackend;
+        $this->addressBookInfo = $addressBookInfo;
+
+    }
+
+    /**
+     * Returns the name of the addressbook
+     *
+     * @return string
+     */
+    function getName() {
+
+        return $this->addressBookInfo['uri'];
+
+    }
+
+    /**
+     * Returns a card
+     *
+     * @param string $name
+     * @return \ICard
+     */
+    function getChild($name) {
+
+        $obj = $this->carddavBackend->getCard($this->addressBookInfo['id'], $name);
+        if (!$obj) throw new DAV\Exception\NotFound('Card not found');
+        return new Card($this->carddavBackend, $this->addressBookInfo, $obj);
+
+    }
+
+    /**
+     * Returns the full list of cards
+     *
+     * @return array
+     */
+    function getChildren() {
+
+        $objs = $this->carddavBackend->getCards($this->addressBookInfo['id']);
+        $children = [];
+        foreach ($objs as $obj) {
+            $obj['acl'] = $this->getChildACL();
+            $children[] = new Card($this->carddavBackend, $this->addressBookInfo, $obj);
+        }
+        return $children;
+
+    }
+
+    /**
+     * This method receives a list of paths in it's first argument.
+     * It must return an array with Node objects.
+     *
+     * If any children are not found, you do not have to return them.
+     *
+     * @param string[] $paths
+     * @return array
+     */
+    function getMultipleChildren(array $paths) {
+
+        $objs = $this->carddavBackend->getMultipleCards($this->addressBookInfo['id'], $paths);
+        $children = [];
+        foreach ($objs as $obj) {
+            $obj['acl'] = $this->getChildACL();
+            $children[] = new Card($this->carddavBackend, $this->addressBookInfo, $obj);
+        }
+        return $children;
+
+    }
+
+    /**
+     * Creates a new directory
+     *
+     * We actually block this, as subdirectories are not allowed in addressbooks.
+     *
+     * @param string $name
+     * @return void
+     */
+    function createDirectory($name) {
+
+        throw new DAV\Exception\MethodNotAllowed('Creating collections in addressbooks is not allowed');
+
+    }
+
+    /**
+     * Creates a new file
+     *
+     * The contents of the new file must be a valid VCARD.
+     *
+     * This method may return an ETag.
+     *
+     * @param string $name
+     * @param resource $vcardData
+     * @return string|null
+     */
+    function createFile($name, $vcardData = null) {
+
+        if (is_resource($vcardData)) {
+            $vcardData = stream_get_contents($vcardData);
+        }
+        // Converting to UTF-8, if needed
+        $vcardData = DAV\StringUtil::ensureUTF8($vcardData);
+
+        return $this->carddavBackend->createCard($this->addressBookInfo['id'], $name, $vcardData);
+
+    }
+
+    /**
+     * Deletes the entire addressbook.
+     *
+     * @return void
+     */
+    function delete() {
+
+        $this->carddavBackend->deleteAddressBook($this->addressBookInfo['id']);
+
+    }
+
+    /**
+     * Renames the addressbook
+     *
+     * @param string $newName
+     * @return void
+     */
+    function setName($newName) {
+
+        throw new DAV\Exception\MethodNotAllowed('Renaming addressbooks is not yet supported');
+
+    }
+
+    /**
+     * Returns the last modification date as a unix timestamp.
+     *
+     * @return void
+     */
+    function getLastModified() {
+
+        return null;
+
+    }
+
+    /**
+     * 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 $this->carddavBackend->updateAddressBook($this->addressBookInfo['id'], $propPatch);
+
+    }
+
+    /**
+     * Returns a list of properties for this nodes.
+     *
+     * The properties list is a list of propertynames the client requested,
+     * encoded in clark-notation {xmlnamespace}tagname
+     *
+     * If the array is empty, it means 'all properties' were requested.
+     *
+     * @param array $properties
+     * @return array
+     */
+    function getProperties($properties) {
+
+        $response = [];
+        foreach ($properties as $propertyName) {
+
+            if (isset($this->addressBookInfo[$propertyName])) {
+
+                $response[$propertyName] = $this->addressBookInfo[$propertyName];
+
+            }
+
+        }
+
+        return $response;
+
+    }
+
+    /**
+     * 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->addressBookInfo['principaluri'];
+
+    }
+
+    /**
+     * 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' => $this->getOwner(),
+                'protected' => true,
+            ],
+            [
+                'privilege' => '{DAV:}write',
+                'principal' => $this->getOwner(),
+                'protected' => true,
+            ],
+
+        ];
+
+    }
+
+    /**
+     * This method returns the ACL's for card nodes in this address book.
+     * The result of this method automatically gets passed to the
+     * card nodes in this address book.
+     *
+     * @return array
+     */
+    function getChildACL() {
+
+        return [
+            [
+                'privilege' => '{DAV:}read',
+                'principal' => $this->getOwner(),
+                'protected' => true,
+            ],
+            [
+                'privilege' => '{DAV:}write',
+                'principal' => $this->getOwner(),
+                '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('Changing ACL is not yet supported');
+
+    }
+
+    /**
+     * 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;
+
+    }
+
+    /**
+     * This method returns the current sync-token for this collection.
+     * This can be any string.
+     *
+     * If null is returned from this function, the plugin assumes there's no
+     * sync information available.
+     *
+     * @return string|null
+     */
+    function getSyncToken() {
+
+        if (
+            $this->carddavBackend instanceof Backend\SyncSupport &&
+            isset($this->addressBookInfo['{DAV:}sync-token'])
+        ) {
+            return $this->addressBookInfo['{DAV:}sync-token'];
+        }
+        if (
+            $this->carddavBackend instanceof Backend\SyncSupport &&
+            isset($this->addressBookInfo['{http://sabredav.org/ns}sync-token'])
+        ) {
+            return $this->addressBookInfo['{http://sabredav.org/ns}sync-token'];
+        }
+
+    }
+
+    /**
+     * The getChanges method returns all the changes that have happened, since
+     * the specified syncToken and the current collection.
+     *
+     * This function should return an array, such as the following:
+     *
+     * [
+     *   'syncToken' => 'The current synctoken',
+     *   'added'   => [
+     *      'new.txt',
+     *   ],
+     *   'modified'   => [
+     *      'modified.txt',
+     *   ],
+     *   'deleted' => [
+     *      'foo.php.bak',
+     *      'old.txt'
+     *   ]
+     * ];
+     *
+     * The syncToken property should reflect the *current* syncToken of the
+     * collection, as reported getSyncToken(). This is needed here too, to
+     * ensure the operation is atomic.
+     *
+     * If the syncToken is specified as null, this is an initial sync, and all
+     * members should be reported.
+     *
+     * The modified property is an array of nodenames that have changed since
+     * the last token.
+     *
+     * The deleted property is an array with nodenames, that have been deleted
+     * from collection.
+     *
+     * The second argument is basically the 'depth' of the report. If it's 1,
+     * you only have to report changes that happened only directly in immediate
+     * descendants. If it's 2, it should also include changes from the nodes
+     * below the child collections. (grandchildren)
+     *
+     * The third (optional) argument allows a client to specify how many
+     * results should be returned at most. If the limit is not specified, it
+     * should be treated as infinite.
+     *
+     * If the limit (infinite or not) is higher than you're willing to return,
+     * you should throw a Sabre\DAV\Exception\TooMuchMatches() exception.
+     *
+     * If the syncToken is expired (due to data cleanup) or unknown, you must
+     * return null.
+     *
+     * The limit is 'suggestive'. You are free to ignore it.
+     *
+     * @param string $syncToken
+     * @param int $syncLevel
+     * @param int $limit
+     * @return array
+     */
+    function getChanges($syncToken, $syncLevel, $limit = null) {
+
+        if (!$this->carddavBackend instanceof Backend\SyncSupport) {
+            return null;
+        }
+
+        return $this->carddavBackend->getChangesForAddressBook(
+            $this->addressBookInfo['id'],
+            $syncToken,
+            $syncLevel,
+            $limit
+        );
+
+    }
+}
diff --git a/vendor/sabre/dav/lib/CardDAV/AddressBookHome.php b/vendor/sabre/dav/lib/CardDAV/AddressBookHome.php
new file mode 100644
index 000000000..ebc251832
--- /dev/null
+++ b/vendor/sabre/dav/lib/CardDAV/AddressBookHome.php
@@ -0,0 +1,263 @@
+<?php
+
+namespace Sabre\CardDAV;
+
+use Sabre\DAV;
+use Sabre\DAV\MkCol;
+use Sabre\DAVACL;
+use Sabre\Uri;
+
+/**
+ * AddressBook Home class
+ *
+ * This collection contains a list of addressbooks associated with one user.
+ *
+ * @copyright Copyright (C) fruux GmbH (https://fruux.com/)
+ * @author Evert Pot (http://evertpot.com/)
+ * @license http://sabre.io/license/ Modified BSD License
+ */
+class AddressBookHome extends DAV\Collection implements DAV\IExtendedCollection, DAVACL\IACL {
+
+    /**
+     * Principal uri
+     *
+     * @var array
+     */
+    protected $principalUri;
+
+    /**
+     * carddavBackend
+     *
+     * @var Backend\BackendInterface
+     */
+    protected $carddavBackend;
+
+    /**
+     * Constructor
+     *
+     * @param Backend\BackendInterface $carddavBackend
+     * @param string $principalUri
+     */
+    function __construct(Backend\BackendInterface $carddavBackend, $principalUri) {
+
+        $this->carddavBackend = $carddavBackend;
+        $this->principalUri = $principalUri;
+
+    }
+
+    /**
+     * Returns the name of this object
+     *
+     * @return string
+     */
+    function getName() {
+
+        list(, $name) = Uri\split($this->principalUri);
+        return $name;
+
+    }
+
+    /**
+     * Updates the name of this object
+     *
+     * @param string $name
+     * @return void
+     */
+    function setName($name) {
+
+        throw new DAV\Exception\MethodNotAllowed();
+
+    }
+
+    /**
+     * Deletes this object
+     *
+     * @return void
+     */
+    function delete() {
+
+        throw new DAV\Exception\MethodNotAllowed();
+
+    }
+
+    /**
+     * Returns the last modification date
+     *
+     * @return int
+     */
+    function getLastModified() {
+
+        return null;
+
+    }
+
+    /**
+     * Creates a new file under this object.
+     *
+     * This is currently not allowed
+     *
+     * @param string $filename
+     * @param resource $data
+     * @return void
+     */
+    function createFile($filename, $data = null) {
+
+        throw new DAV\Exception\MethodNotAllowed('Creating new files in this collection is not supported');
+
+    }
+
+    /**
+     * Creates a new directory under this object.
+     *
+     * This is currently not allowed.
+     *
+     * @param string $filename
+     * @return void
+     */
+    function createDirectory($filename) {
+
+        throw new DAV\Exception\MethodNotAllowed('Creating new collections in this collection is not supported');
+
+    }
+
+    /**
+     * Returns a single addressbook, by name
+     *
+     * @param string $name
+     * @todo needs optimizing
+     * @return \AddressBook
+     */
+    function getChild($name) {
+
+        foreach ($this->getChildren() as $child) {
+            if ($name == $child->getName())
+                return $child;
+
+        }
+        throw new DAV\Exception\NotFound('Addressbook with name \'' . $name . '\' could not be found');
+
+    }
+
+    /**
+     * Returns a list of addressbooks
+     *
+     * @return array
+     */
+    function getChildren() {
+
+        $addressbooks = $this->carddavBackend->getAddressBooksForUser($this->principalUri);
+        $objs = [];
+        foreach ($addressbooks as $addressbook) {
+            $objs[] = new AddressBook($this->carddavBackend, $addressbook);
+        }
+        return $objs;
+
+    }
+
+    /**
+     * Creates a new address book.
+     *
+     * @param string $name
+     * @param MkCol $mkCol
+     * @throws DAV\Exception\InvalidResourceType
+     * @return void
+     */
+    function createExtendedCollection($name, MkCol $mkCol) {
+
+        if (!$mkCol->hasResourceType('{' . Plugin::NS_CARDDAV . '}addressbook')) {
+            throw new DAV\Exception\InvalidResourceType('Unknown resourceType for this collection');
+        }
+        $properties = $mkCol->getRemainingValues();
+        $mkCol->setRemainingResultCode(201);
+        $this->carddavBackend->createAddressBook($this->principalUri, $name, $properties);
+
+    }
+
+    /**
+     * 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->principalUri;
+
+    }
+
+    /**
+     * 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' => $this->principalUri,
+                'protected' => true,
+            ],
+            [
+                'privilege' => '{DAV:}write',
+                'principal' => $this->principalUri,
+                '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('Changing ACL is not yet supported');
+
+    }
+
+    /**
+     * 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/CardDAV/AddressBookRoot.php b/vendor/sabre/dav/lib/CardDAV/AddressBookRoot.php
new file mode 100644
index 000000000..4a33df4ec
--- /dev/null
+++ b/vendor/sabre/dav/lib/CardDAV/AddressBookRoot.php
@@ -0,0 +1,80 @@
+<?php
+
+namespace Sabre\CardDAV;
+
+use Sabre\DAVACL;
+
+/**
+ * AddressBook rootnode
+ *
+ * This object lists a collection of users, which can contain addressbooks.
+ *
+ * @copyright Copyright (C) fruux GmbH (https://fruux.com/)
+ * @author Evert Pot (http://evertpot.com/)
+ * @license http://sabre.io/license/ Modified BSD License
+ */
+class AddressBookRoot extends DAVACL\AbstractPrincipalCollection {
+
+    /**
+     * Principal Backend
+     *
+     * @var Sabre\DAVACL\PrincipalBackend\BackendInteface
+     */
+    protected $principalBackend;
+
+    /**
+     * CardDAV backend
+     *
+     * @var Backend\BackendInterface
+     */
+    protected $carddavBackend;
+
+    /**
+     * Constructor
+     *
+     * This constructor needs both a principal and a carddav backend.
+     *
+     * By default this class will show a list of addressbook collections for
+     * principals in the 'principals' collection. If your main principals are
+     * actually located in a different path, use the $principalPrefix argument
+     * to override this.
+     *
+     * @param DAVACL\PrincipalBackend\BackendInterface $principalBackend
+     * @param Backend\BackendInterface $carddavBackend
+     * @param string $principalPrefix
+     */
+    function __construct(DAVACL\PrincipalBackend\BackendInterface $principalBackend, Backend\BackendInterface $carddavBackend, $principalPrefix = 'principals') {
+
+        $this->carddavBackend = $carddavBackend;
+        parent::__construct($principalBackend, $principalPrefix);
+
+    }
+
+    /**
+     * Returns the name of the node
+     *
+     * @return string
+     */
+    function getName() {
+
+        return Plugin::ADDRESSBOOK_ROOT;
+
+    }
+
+    /**
+     * 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 $principal) {
+
+        return new AddressBookHome($this->carddavBackend, $principal['uri']);
+
+    }
+
+}
diff --git a/vendor/sabre/dav/lib/CardDAV/Backend/AbstractBackend.php b/vendor/sabre/dav/lib/CardDAV/Backend/AbstractBackend.php
new file mode 100644
index 000000000..03d2346da
--- /dev/null
+++ b/vendor/sabre/dav/lib/CardDAV/Backend/AbstractBackend.php
@@ -0,0 +1,38 @@
+<?php
+
+namespace Sabre\CardDAV\Backend;
+
+/**
+ * CardDAV abstract Backend
+ *
+ * This class serves as a base-class for addressbook backends
+ *
+ * This class doesn't do much, but it was added for consistency.
+ *
+ * @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 {
+
+    /**
+     * Returns a list of cards.
+     *
+     * This method should work identical to getCard, but instead return all the
+     * cards in the list as an array.
+     *
+     * If the backend supports this, it may allow for some speed-ups.
+     *
+     * @param mixed $addressBookId
+     * @param array $uris
+     * @return array
+     */
+    function getMultipleCards($addressBookId, array $uris) {
+
+        return array_map(function($uri) use ($addressBookId) {
+            return $this->getCard($addressBookId, $uri);
+        }, $uris);
+
+    }
+
+}
diff --git a/vendor/sabre/dav/lib/CardDAV/Backend/BackendInterface.php b/vendor/sabre/dav/lib/CardDAV/Backend/BackendInterface.php
new file mode 100644
index 000000000..b9691b906
--- /dev/null
+++ b/vendor/sabre/dav/lib/CardDAV/Backend/BackendInterface.php
@@ -0,0 +1,187 @@
+<?php
+
+namespace Sabre\CardDAV\Backend;
+
+/**
+ * CardDAV Backend Interface
+ *
+ * Any CardDAV backend must implement this interface.
+ *
+ * Note that there are references to 'addressBookId' scattered throughout the
+ * class. The value of the addressBookId is completely up to you, it can be any
+ * arbitrary value you can use as an unique identifier.
+ *
+ * @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 the list of addressbooks for a specific user.
+     *
+     * Every addressbook should have the following properties:
+     *   id - an arbitrary unique id
+     *   uri - the 'basename' part of the url
+     *   principaluri - Same as the passed parameter
+     *
+     * Any additional clark-notation property may be passed besides this. Some
+     * common ones are :
+     *   {DAV:}displayname
+     *   {urn:ietf:params:xml:ns:carddav}addressbook-description
+     *   {http://calendarserver.org/ns/}getctag
+     *
+     * @param string $principalUri
+     * @return array
+     */
+    function getAddressBooksForUser($principalUri);
+
+    /**
+     * Updates properties for an address book.
+     *
+     * 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 $addressBookId
+     * @param \Sabre\DAV\PropPatch $propPatch
+     * @return void
+     */
+    function updateAddressBook($addressBookId, \Sabre\DAV\PropPatch $propPatch);
+
+    /**
+     * Creates a new address book
+     *
+     * @param string $principalUri
+     * @param string $url Just the 'basename' of the url.
+     * @param array $properties
+     * @return void
+     */
+    function createAddressBook($principalUri, $url, array $properties);
+
+    /**
+     * Deletes an entire addressbook and all its contents
+     *
+     * @param mixed $addressBookId
+     * @return void
+     */
+    function deleteAddressBook($addressBookId);
+
+    /**
+     * Returns all cards for a specific addressbook id.
+     *
+     * This method should return the following properties for each card:
+     *   * carddata - raw vcard data
+     *   * uri - Some unique url
+     *   * lastmodified - A unix timestamp
+     *
+     * It's recommended to also return the following properties:
+     *   * etag - A unique etag. This must change every time the card changes.
+     *   * size - The size of the card in bytes.
+     *
+     * If these last two properties are provided, less time will be spent
+     * calculating them. If they are specified, you can also ommit carddata.
+     * This may speed up certain requests, especially with large cards.
+     *
+     * @param mixed $addressbookId
+     * @return array
+     */
+    function getCards($addressbookId);
+
+    /**
+     * Returns a specfic card.
+     *
+     * The same set of properties must be returned as with getCards. The only
+     * exception is that 'carddata' is absolutely required.
+     *
+     * If the card does not exist, you must return false.
+     *
+     * @param mixed $addressBookId
+     * @param string $cardUri
+     * @return array
+     */
+    function getCard($addressBookId, $cardUri);
+
+    /**
+     * Returns a list of cards.
+     *
+     * This method should work identical to getCard, but instead return all the
+     * cards in the list as an array.
+     *
+     * If the backend supports this, it may allow for some speed-ups.
+     *
+     * @param mixed $addressBookId
+     * @param array $uris
+     * @return array
+     */
+    function getMultipleCards($addressBookId, array $uris);
+
+    /**
+     * Creates a new card.
+     *
+     * The addressbook id will be passed as the first argument. This is the
+     * same id as it is returned from the getAddressBooksForUser method.
+     *
+     * The cardUri is a base uri, and doesn't include the full path. The
+     * cardData argument is the vcard body, and is passed as a string.
+     *
+     * It is possible to return an ETag from this method. This ETag is for the
+     * newly created resource, and must be enclosed with double quotes (that
+     * is, the string itself must contain the double quotes).
+     *
+     * You should only return the ETag if you store the carddata as-is. If a
+     * subsequent GET request on the same card does not have the same body,
+     * byte-by-byte and you did return an ETag here, clients tend to get
+     * confused.
+     *
+     * If you don't return an ETag, you can just return null.
+     *
+     * @param mixed $addressBookId
+     * @param string $cardUri
+     * @param string $cardData
+     * @return string|null
+     */
+    function createCard($addressBookId, $cardUri, $cardData);
+
+    /**
+     * Updates a card.
+     *
+     * The addressbook id will be passed as the first argument. This is the
+     * same id as it is returned from the getAddressBooksForUser method.
+     *
+     * The cardUri is a base uri, and doesn't include the full path. The
+     * cardData argument is the vcard body, and is passed as a string.
+     *
+     * It is possible to return an ETag from this method. This ETag should
+     * match that of the updated resource, and must be enclosed with double
+     * quotes (that is: the string itself must contain the actual quotes).
+     *
+     * You should only return the ETag if you store the carddata as-is. If a
+     * subsequent GET request on the same card does not have the same body,
+     * byte-by-byte and you did return an ETag here, clients tend to get
+     * confused.
+     *
+     * If you don't return an ETag, you can just return null.
+     *
+     * @param mixed $addressBookId
+     * @param string $cardUri
+     * @param string $cardData
+     * @return string|null
+     */
+    function updateCard($addressBookId, $cardUri, $cardData);
+
+    /**
+     * Deletes a card
+     *
+     * @param mixed $addressBookId
+     * @param string $cardUri
+     * @return bool
+     */
+    function deleteCard($addressBookId, $cardUri);
+
+}
diff --git a/vendor/sabre/dav/lib/CardDAV/Backend/PDO.php b/vendor/sabre/dav/lib/CardDAV/Backend/PDO.php
new file mode 100644
index 000000000..5509ddc02
--- /dev/null
+++ b/vendor/sabre/dav/lib/CardDAV/Backend/PDO.php
@@ -0,0 +1,545 @@
+<?php
+
+namespace Sabre\CardDAV\Backend;
+
+use Sabre\CardDAV;
+use Sabre\DAV;
+
+/**
+ * PDO CardDAV backend
+ *
+ * This CardDAV backend uses PDO to store addressbooks
+ *
+ * @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 SyncSupport {
+
+    /**
+     * PDO connection
+     *
+     * @var PDO
+     */
+    protected $pdo;
+
+    /**
+     * The PDO table name used to store addressbooks
+     */
+    public $addressBooksTableName = 'addressbooks';
+
+    /**
+     * The PDO table name used to store cards
+     */
+    public $cardsTableName = 'cards';
+
+    /**
+     * The table name that will be used for tracking changes in address books.
+     *
+     * @var string
+     */
+    public $addressBookChangesTableName = 'addressbookchanges';
+
+    /**
+     * Sets up the object
+     *
+     * @param \PDO $pdo
+     */
+    function __construct(\PDO $pdo) {
+
+        $this->pdo = $pdo;
+
+    }
+
+    /**
+     * Returns the list of addressbooks for a specific user.
+     *
+     * @param string $principalUri
+     * @return array
+     */
+    function getAddressBooksForUser($principalUri) {
+
+        $stmt = $this->pdo->prepare('SELECT id, uri, displayname, principaluri, description, synctoken FROM ' . $this->addressBooksTableName . ' WHERE principaluri = ?');
+        $stmt->execute([$principalUri]);
+
+        $addressBooks = [];
+
+        foreach ($stmt->fetchAll() as $row) {
+
+            $addressBooks[] = [
+                'id'                                                          => $row['id'],
+                'uri'                                                         => $row['uri'],
+                'principaluri'                                                => $row['principaluri'],
+                '{DAV:}displayname'                                           => $row['displayname'],
+                '{' . CardDAV\Plugin::NS_CARDDAV . '}addressbook-description' => $row['description'],
+                '{http://calendarserver.org/ns/}getctag'                      => $row['synctoken'],
+                '{http://sabredav.org/ns}sync-token'                          => $row['synctoken'] ? $row['synctoken'] : '0',
+            ];
+
+        }
+
+        return $addressBooks;
+
+    }
+
+
+    /**
+     * Updates properties for an address book.
+     *
+     * 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 $addressBookId
+     * @param \Sabre\DAV\PropPatch $propPatch
+     * @return void
+     */
+    function updateAddressBook($addressBookId, \Sabre\DAV\PropPatch $propPatch) {
+
+        $supportedProperties = [
+            '{DAV:}displayname',
+            '{' . CardDAV\Plugin::NS_CARDDAV . '}addressbook-description',
+        ];
+
+        $propPatch->handle($supportedProperties, function($mutations) use ($addressBookId) {
+
+            $updates = [];
+            foreach ($mutations as $property => $newValue) {
+
+                switch ($property) {
+                    case '{DAV:}displayname' :
+                        $updates['displayname'] = $newValue;
+                        break;
+                    case '{' . CardDAV\Plugin::NS_CARDDAV . '}addressbook-description' :
+                        $updates['description'] = $newValue;
+                        break;
+                }
+            }
+            $query = 'UPDATE ' . $this->addressBooksTableName . ' SET ';
+            $first = true;
+            foreach ($updates as $key => $value) {
+                if ($first) {
+                    $first = false;
+                } else {
+                    $query .= ', ';
+                }
+                $query .= ' `' . $key . '` = :' . $key . ' ';
+            }
+            $query .= ' WHERE id = :addressbookid';
+
+            $stmt = $this->pdo->prepare($query);
+            $updates['addressbookid'] = $addressBookId;
+
+            $stmt->execute($updates);
+
+            $this->addChange($addressBookId, "", 2);
+
+            return true;
+
+        });
+
+    }
+
+    /**
+     * Creates a new address book
+     *
+     * @param string $principalUri
+     * @param string $url Just the 'basename' of the url.
+     * @param array $properties
+     * @return int Last insert id
+     */
+    function createAddressBook($principalUri, $url, array $properties) {
+
+        $values = [
+            'displayname'  => null,
+            'description'  => null,
+            'principaluri' => $principalUri,
+            'uri'          => $url,
+        ];
+
+        foreach ($properties as $property => $newValue) {
+
+            switch ($property) {
+                case '{DAV:}displayname' :
+                    $values['displayname'] = $newValue;
+                    break;
+                case '{' . CardDAV\Plugin::NS_CARDDAV . '}addressbook-description' :
+                    $values['description'] = $newValue;
+                    break;
+                default :
+                    throw new DAV\Exception\BadRequest('Unknown property: ' . $property);
+            }
+
+        }
+
+        $query = 'INSERT INTO ' . $this->addressBooksTableName . ' (uri, displayname, description, principaluri, synctoken) VALUES (:uri, :displayname, :description, :principaluri, 1)';
+        $stmt = $this->pdo->prepare($query);
+        $stmt->execute($values);
+        return $this->pdo->lastInsertId();
+
+    }
+
+    /**
+     * Deletes an entire addressbook and all its contents
+     *
+     * @param int $addressBookId
+     * @return void
+     */
+    function deleteAddressBook($addressBookId) {
+
+        $stmt = $this->pdo->prepare('DELETE FROM ' . $this->cardsTableName . ' WHERE addressbookid = ?');
+        $stmt->execute([$addressBookId]);
+
+        $stmt = $this->pdo->prepare('DELETE FROM ' . $this->addressBooksTableName . ' WHERE id = ?');
+        $stmt->execute([$addressBookId]);
+
+        $stmt = $this->pdo->prepare('DELETE FROM ' . $this->addressBookChangesTableName . ' WHERE addressbookid = ?');
+        $stmt->execute([$addressBookId]);
+
+    }
+
+    /**
+     * Returns all cards for a specific addressbook id.
+     *
+     * This method should return the following properties for each card:
+     *   * carddata - raw vcard data
+     *   * uri - Some unique url
+     *   * lastmodified - A unix timestamp
+     *
+     * It's recommended to also return the following properties:
+     *   * etag - A unique etag. This must change every time the card changes.
+     *   * size - The size of the card in bytes.
+     *
+     * If these last two properties are provided, less time will be spent
+     * calculating them. If they are specified, you can also ommit carddata.
+     * This may speed up certain requests, especially with large cards.
+     *
+     * @param mixed $addressbookId
+     * @return array
+     */
+    function getCards($addressbookId) {
+
+        $stmt = $this->pdo->prepare('SELECT id, uri, lastmodified, etag, size FROM ' . $this->cardsTableName . ' WHERE addressbookid = ?');
+        $stmt->execute([$addressbookId]);
+
+        $result = [];
+        while ($row = $stmt->fetch(\PDO::FETCH_ASSOC)) {
+            $row['etag'] = '"' . $row['etag'] . '"';
+            $result[] = $row;
+        }
+        return $result;
+
+    }
+
+    /**
+     * Returns a specfic card.
+     *
+     * The same set of properties must be returned as with getCards. The only
+     * exception is that 'carddata' is absolutely required.
+     *
+     * If the card does not exist, you must return false.
+     *
+     * @param mixed $addressBookId
+     * @param string $cardUri
+     * @return array
+     */
+    function getCard($addressBookId, $cardUri) {
+
+        $stmt = $this->pdo->prepare('SELECT id, carddata, uri, lastmodified, etag, size FROM ' . $this->cardsTableName . ' WHERE addressbookid = ? AND uri = ? LIMIT 1');
+        $stmt->execute([$addressBookId, $cardUri]);
+
+        $result = $stmt->fetch(\PDO::FETCH_ASSOC);
+
+        if (!$result) return false;
+
+        $result['etag'] = '"' . $result['etag'] . '"';
+        return $result;
+
+    }
+
+    /**
+     * Returns a list of cards.
+     *
+     * This method should work identical to getCard, but instead return all the
+     * cards in the list as an array.
+     *
+     * If the backend supports this, it may allow for some speed-ups.
+     *
+     * @param mixed $addressBookId
+     * @param array $uris
+     * @return array
+     */
+    function getMultipleCards($addressBookId, array $uris) {
+
+        $query = 'SELECT id, uri, lastmodified, etag, size, carddata FROM ' . $this->cardsTableName . ' WHERE addressbookid = ? AND uri IN (';
+        // Inserting a whole bunch of question marks
+        $query .= implode(',', array_fill(0, count($uris), '?'));
+        $query .= ')';
+
+        $stmt = $this->pdo->prepare($query);
+        $stmt->execute(array_merge([$addressBookId], $uris));
+        $result = [];
+        while ($row = $stmt->fetch(\PDO::FETCH_ASSOC)) {
+            $row['etag'] = '"' . $row['etag'] . '"';
+            $result[] = $row;
+        }
+        return $result;
+
+    }
+
+    /**
+     * Creates a new card.
+     *
+     * The addressbook id will be passed as the first argument. This is the
+     * same id as it is returned from the getAddressBooksForUser method.
+     *
+     * The cardUri is a base uri, and doesn't include the full path. The
+     * cardData argument is the vcard body, and is passed as a string.
+     *
+     * It is possible to return an ETag from this method. This ETag is for the
+     * newly created resource, and must be enclosed with double quotes (that
+     * is, the string itself must contain the double quotes).
+     *
+     * You should only return the ETag if you store the carddata as-is. If a
+     * subsequent GET request on the same card does not have the same body,
+     * byte-by-byte and you did return an ETag here, clients tend to get
+     * confused.
+     *
+     * If you don't return an ETag, you can just return null.
+     *
+     * @param mixed $addressBookId
+     * @param string $cardUri
+     * @param string $cardData
+     * @return string|null
+     */
+    function createCard($addressBookId, $cardUri, $cardData) {
+
+        $stmt = $this->pdo->prepare('INSERT INTO ' . $this->cardsTableName . ' (carddata, uri, lastmodified, addressbookid, size, etag) VALUES (?, ?, ?, ?, ?, ?)');
+
+        $etag = md5($cardData);
+
+        $stmt->execute([
+            $cardData,
+            $cardUri,
+            time(),
+            $addressBookId,
+            strlen($cardData),
+            $etag,
+        ]);
+
+        $this->addChange($addressBookId, $cardUri, 1);
+
+        return '"' . $etag . '"';
+
+    }
+
+    /**
+     * Updates a card.
+     *
+     * The addressbook id will be passed as the first argument. This is the
+     * same id as it is returned from the getAddressBooksForUser method.
+     *
+     * The cardUri is a base uri, and doesn't include the full path. The
+     * cardData argument is the vcard body, and is passed as a string.
+     *
+     * It is possible to return an ETag from this method. This ETag should
+     * match that of the updated resource, and must be enclosed with double
+     * quotes (that is: the string itself must contain the actual quotes).
+     *
+     * You should only return the ETag if you store the carddata as-is. If a
+     * subsequent GET request on the same card does not have the same body,
+     * byte-by-byte and you did return an ETag here, clients tend to get
+     * confused.
+     *
+     * If you don't return an ETag, you can just return null.
+     *
+     * @param mixed $addressBookId
+     * @param string $cardUri
+     * @param string $cardData
+     * @return string|null
+     */
+    function updateCard($addressBookId, $cardUri, $cardData) {
+
+        $stmt = $this->pdo->prepare('UPDATE ' . $this->cardsTableName . ' SET carddata = ?, lastmodified = ?, size = ?, etag = ? WHERE uri = ? AND addressbookid =?');
+
+        $etag = md5($cardData);
+        $stmt->execute([
+            $cardData,
+            time(),
+            strlen($cardData),
+            $etag,
+            $cardUri,
+            $addressBookId
+        ]);
+
+        $this->addChange($addressBookId, $cardUri, 2);
+
+        return '"' . $etag . '"';
+
+    }
+
+    /**
+     * Deletes a card
+     *
+     * @param mixed $addressBookId
+     * @param string $cardUri
+     * @return bool
+     */
+    function deleteCard($addressBookId, $cardUri) {
+
+        $stmt = $this->pdo->prepare('DELETE FROM ' . $this->cardsTableName . ' WHERE addressbookid = ? AND uri = ?');
+        $stmt->execute([$addressBookId, $cardUri]);
+
+        $this->addChange($addressBookId, $cardUri, 3);
+
+        return $stmt->rowCount() === 1;
+
+    }
+
+    /**
+     * The getChanges method returns all the changes that have happened, since
+     * the specified syncToken in the specified address book.
+     *
+     * This function should return an array, such as the following:
+     *
+     * [
+     *   'syncToken' => 'The current synctoken',
+     *   'added'   => [
+     *      'new.txt',
+     *   ],
+     *   'modified'   => [
+     *      'updated.txt',
+     *   ],
+     *   'deleted' => [
+     *      'foo.php.bak',
+     *      'old.txt'
+     *   ]
+     * ];
+     *
+     * The returned syncToken property should reflect the *current* syncToken
+     * of the addressbook, as reported in the {http://sabredav.org/ns}sync-token
+     * property. This is needed here too, to ensure the operation is atomic.
+     *
+     * If the $syncToken argument is specified as null, this is an initial
+     * sync, and all members should be reported.
+     *
+     * The modified property is an array of nodenames that have changed since
+     * the last token.
+     *
+     * The deleted property is an array with nodenames, that have been deleted
+     * from collection.
+     *
+     * The $syncLevel argument is basically the 'depth' of the report. If it's
+     * 1, you only have to report changes that happened only directly in
+     * immediate descendants. If it's 2, it should also include changes from
+     * the nodes below the child collections. (grandchildren)
+     *
+     * The $limit argument allows a client to specify how many results should
+     * be returned at most. If the limit is not specified, it should be treated
+     * as infinite.
+     *
+     * If the limit (infinite or not) is higher than you're willing to return,
+     * you should throw a Sabre\DAV\Exception\TooMuchMatches() exception.
+     *
+     * If the syncToken is expired (due to data cleanup) or unknown, you must
+     * return null.
+     *
+     * The limit is 'suggestive'. You are free to ignore it.
+     *
+     * @param string $addressBookId
+     * @param string $syncToken
+     * @param int $syncLevel
+     * @param int $limit
+     * @return array
+     */
+    function getChangesForAddressBook($addressBookId, $syncToken, $syncLevel, $limit = null) {
+
+        // Current synctoken
+        $stmt = $this->pdo->prepare('SELECT synctoken FROM ' . $this->addressBooksTableName . ' WHERE id = ?');
+        $stmt->execute([ $addressBookId ]);
+        $currentToken = $stmt->fetchColumn(0);
+
+        if (is_null($currentToken)) return null;
+
+        $result = [
+            'syncToken' => $currentToken,
+            'added'     => [],
+            'modified'  => [],
+            'deleted'   => [],
+        ];
+
+        if ($syncToken) {
+
+            $query = "SELECT uri, operation FROM " . $this->addressBookChangesTableName . " WHERE synctoken >= ? AND synctoken < ? AND addressbookid = ? ORDER BY synctoken";
+            if ($limit > 0) $query .= " LIMIT " . (int)$limit;
+
+            // Fetching all changes
+            $stmt = $this->pdo->prepare($query);
+            $stmt->execute([$syncToken, $currentToken, $addressBookId]);
+
+            $changes = [];
+
+            // This loop ensures that any duplicates are overwritten, only the
+            // last change on a node is relevant.
+            while ($row = $stmt->fetch(\PDO::FETCH_ASSOC)) {
+
+                $changes[$row['uri']] = $row['operation'];
+
+            }
+
+            foreach ($changes as $uri => $operation) {
+
+                switch ($operation) {
+                    case 1:
+                        $result['added'][] = $uri;
+                        break;
+                    case 2:
+                        $result['modified'][] = $uri;
+                        break;
+                    case 3:
+                        $result['deleted'][] = $uri;
+                        break;
+                }
+
+            }
+        } else {
+            // No synctoken supplied, this is the initial sync.
+            $query = "SELECT uri FROM " . $this->cardsTableName . " WHERE addressbookid = ?";
+            $stmt = $this->pdo->prepare($query);
+            $stmt->execute([$addressBookId]);
+
+            $result['added'] = $stmt->fetchAll(\PDO::FETCH_COLUMN);
+        }
+        return $result;
+
+    }
+
+    /**
+     * Adds a change record to the addressbookchanges table.
+     *
+     * @param mixed $addressBookId
+     * @param string $objectUri
+     * @param int $operation 1 = add, 2 = modify, 3 = delete
+     * @return void
+     */
+    protected function addChange($addressBookId, $objectUri, $operation) {
+
+        $stmt = $this->pdo->prepare('INSERT INTO ' . $this->addressBookChangesTableName . ' (uri, synctoken, addressbookid, operation) SELECT ?, synctoken, ?, ? FROM ' . $this->addressBooksTableName . ' WHERE id = ?');
+        $stmt->execute([
+            $objectUri,
+            $addressBookId,
+            $operation,
+            $addressBookId
+        ]);
+        $stmt = $this->pdo->prepare('UPDATE ' . $this->addressBooksTableName . ' SET synctoken = synctoken + 1 WHERE id = ?');
+        $stmt->execute([
+            $addressBookId
+        ]);
+
+    }
+}
diff --git a/vendor/sabre/dav/lib/CardDAV/Backend/SyncSupport.php b/vendor/sabre/dav/lib/CardDAV/Backend/SyncSupport.php
new file mode 100644
index 000000000..f80618a8e
--- /dev/null
+++ b/vendor/sabre/dav/lib/CardDAV/Backend/SyncSupport.php
@@ -0,0 +1,81 @@
+<?php
+
+namespace Sabre\CardDAV\Backend;
+
+/**
+ * WebDAV-sync support for CardDAV backends.
+ *
+ * In order for backends to advertise support for WebDAV-sync, this interface
+ * must be implemented.
+ *
+ * Implementing this can result in a significant reduction of bandwidth and CPU
+ * time.
+ *
+ * For this to work, you _must_ return a {http://sabredav.org/ns}sync-token
+ * property from getAddressBooksForUser.
+ *
+ * @copyright Copyright (C) fruux GmbH (https://fruux.com/)
+ * @author Evert Pot (http://evertpot.com/)
+ * @license http://sabre.io/license/ Modified BSD License
+ */
+interface SyncSupport extends BackendInterface {
+
+    /**
+     * The getChanges method returns all the changes that have happened, since
+     * the specified syncToken in the specified address book.
+     *
+     * This function should return an array, such as the following:
+     *
+     * [
+     *   'syncToken' => 'The current synctoken',
+     *   'added'   => [
+     *      'new.txt',
+     *   ],
+     *   'modified'   => [
+     *      'modified.txt',
+     *   ],
+     *   'deleted' => [
+     *      'foo.php.bak',
+     *      'old.txt'
+     *   ]
+     * ];
+     *
+     * The returned syncToken property should reflect the *current* syncToken
+     * of the calendar, as reported in the {http://sabredav.org/ns}sync-token
+     * property. This is needed here too, to ensure the operation is atomic.
+     *
+     * If the $syncToken argument is specified as null, this is an initial
+     * sync, and all members should be reported.
+     *
+     * The modified property is an array of nodenames that have changed since
+     * the last token.
+     *
+     * The deleted property is an array with nodenames, that have been deleted
+     * from collection.
+     *
+     * The $syncLevel argument is basically the 'depth' of the report. If it's
+     * 1, you only have to report changes that happened only directly in
+     * immediate descendants. If it's 2, it should also include changes from
+     * the nodes below the child collections. (grandchildren)
+     *
+     * The $limit argument allows a client to specify how many results should
+     * be returned at most. If the limit is not specified, it should be treated
+     * as infinite.
+     *
+     * If the limit (infinite or not) is higher than you're willing to return,
+     * you should throw a Sabre\DAV\Exception\TooMuchMatches() exception.
+     *
+     * If the syncToken is expired (due to data cleanup) or unknown, you must
+     * return null.
+     *
+     * The limit is 'suggestive'. You are free to ignore it.
+     *
+     * @param string $addressBookId
+     * @param string $syncToken
+     * @param int $syncLevel
+     * @param int $limit
+     * @return array
+     */
+    function getChangesForAddressBook($addressBookId, $syncToken, $syncLevel, $limit = null);
+
+}
diff --git a/vendor/sabre/dav/lib/CardDAV/Card.php b/vendor/sabre/dav/lib/CardDAV/Card.php
new file mode 100644
index 000000000..8da672502
--- /dev/null
+++ b/vendor/sabre/dav/lib/CardDAV/Card.php
@@ -0,0 +1,263 @@
+<?php
+
+namespace Sabre\CardDAV;
+
+use Sabre\DAVACL;
+use Sabre\DAV;
+
+/**
+ * The Card object represents a single Card from an addressbook
+ *
+ * @copyright Copyright (C) fruux GmbH (https://fruux.com/)
+ * @author Evert Pot (http://evertpot.com/)
+ * @license http://sabre.io/license/ Modified BSD License
+ */
+class Card extends DAV\File implements ICard, DAVACL\IACL {
+
+    /**
+     * CardDAV backend
+     *
+     * @var Backend\BackendInterface
+     */
+    protected $carddavBackend;
+
+    /**
+     * Array with information about this Card
+     *
+     * @var array
+     */
+    protected $cardData;
+
+    /**
+     * Array with information about the containing addressbook
+     *
+     * @var array
+     */
+    protected $addressBookInfo;
+
+    /**
+     * Constructor
+     *
+     * @param Backend\BackendInterface $carddavBackend
+     * @param array $addressBookInfo
+     * @param array $cardData
+     */
+    function __construct(Backend\BackendInterface $carddavBackend, array $addressBookInfo, array $cardData) {
+
+        $this->carddavBackend = $carddavBackend;
+        $this->addressBookInfo = $addressBookInfo;
+        $this->cardData = $cardData;
+
+    }
+
+    /**
+     * Returns the uri for this object
+     *
+     * @return string
+     */
+    function getName() {
+
+        return $this->cardData['uri'];
+
+    }
+
+    /**
+     * Returns the VCard-formatted object
+     *
+     * @return string
+     */
+    function get() {
+
+        // Pre-populating 'carddata' is optional. If we don't yet have it
+        // already, we fetch it from the backend.
+        if (!isset($this->cardData['carddata'])) {
+            $this->cardData = $this->carddavBackend->getCard($this->addressBookInfo['id'], $this->cardData['uri']);
+        }
+        return $this->cardData['carddata'];
+
+    }
+
+    /**
+     * Updates the VCard-formatted object
+     *
+     * @param string $cardData
+     * @return string|null
+     */
+    function put($cardData) {
+
+        if (is_resource($cardData))
+            $cardData = stream_get_contents($cardData);
+
+        // Converting to UTF-8, if needed
+        $cardData = DAV\StringUtil::ensureUTF8($cardData);
+
+        $etag = $this->carddavBackend->updateCard($this->addressBookInfo['id'], $this->cardData['uri'], $cardData);
+        $this->cardData['carddata'] = $cardData;
+        $this->cardData['etag'] = $etag;
+
+        return $etag;
+
+    }
+
+    /**
+     * Deletes the card
+     *
+     * @return void
+     */
+    function delete() {
+
+        $this->carddavBackend->deleteCard($this->addressBookInfo['id'], $this->cardData['uri']);
+
+    }
+
+    /**
+     * Returns the mime content-type
+     *
+     * @return string
+     */
+    function getContentType() {
+
+        return 'text/vcard; charset=utf-8';
+
+    }
+
+    /**
+     * Returns an ETag for this object
+     *
+     * @return string
+     */
+    function getETag() {
+
+        if (isset($this->cardData['etag'])) {
+            return $this->cardData['etag'];
+        } else {
+            $data = $this->get();
+            if (is_string($data)) {
+                return '"' . md5($data) . '"';
+            } else {
+                // We refuse to calculate the md5 if it's a stream.
+                return null;
+            }
+        }
+
+    }
+
+    /**
+     * Returns the last modification date as a unix timestamp
+     *
+     * @return int
+     */
+    function getLastModified() {
+
+        return isset($this->cardData['lastmodified']) ? $this->cardData['lastmodified'] : null;
+
+    }
+
+    /**
+     * Returns the size of this object in bytes
+     *
+     * @return int
+     */
+    function getSize() {
+
+        if (array_key_exists('size', $this->cardData)) {
+            return $this->cardData['size'];
+        } else {
+            return strlen($this->get());
+        }
+
+    }
+
+    /**
+     * 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 $this->addressBookInfo['principaluri'];
+
+    }
+
+    /**
+     * Returns a group principal
+     *
+     * This must be a url to a principal, or null if there's no owner
+     *
+     * @return string|null
+     */
+    function getGroup() {
+
+        return null;
+
+    }
+
+    /**
+     * Returns a list of ACE's for this node.
+     *
+     * Each ACE has the following properties:
+     *   * 'privilege', a string such as {DAV:}read or {DAV:}write. These are
+     *     currently the only supported privileges
+     *   * 'principal', a url to the principal who owns the node
+     *   * 'protected' (optional), indicating that this ACE is not allowed to
+     *      be updated.
+     *
+     * @return array
+     */
+    function getACL() {
+
+        // An alternative acl may be specified through the cardData array.
+        if (isset($this->cardData['acl'])) {
+            return $this->cardData['acl'];
+        }
+
+        return [
+            [
+                'privilege' => '{DAV:}read',
+                'principal' => $this->addressBookInfo['principaluri'],
+                'protected' => true,
+            ],
+            [
+                'privilege' => '{DAV:}write',
+                'principal' => $this->addressBookInfo['principaluri'],
+                '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('Changing ACL is not yet supported');
+
+    }
+
+    /**
+     * 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/CardDAV/IAddressBook.php b/vendor/sabre/dav/lib/CardDAV/IAddressBook.php
new file mode 100644
index 000000000..f80e05575
--- /dev/null
+++ b/vendor/sabre/dav/lib/CardDAV/IAddressBook.php
@@ -0,0 +1,18 @@
+<?php
+
+namespace Sabre\CardDAV;
+
+use Sabre\DAV;
+
+/**
+ * AddressBook interface
+ *
+ * Implement this interface to allow a node to be recognized as an addressbook.
+ *
+ * @copyright Copyright (C) fruux GmbH (https://fruux.com/)
+ * @author Evert Pot (http://evertpot.com/)
+ * @license http://sabre.io/license/ Modified BSD License
+ */
+interface IAddressBook extends DAV\ICollection {
+
+}
diff --git a/vendor/sabre/dav/lib/CardDAV/ICard.php b/vendor/sabre/dav/lib/CardDAV/ICard.php
new file mode 100644
index 000000000..a974cbd8f
--- /dev/null
+++ b/vendor/sabre/dav/lib/CardDAV/ICard.php
@@ -0,0 +1,19 @@
+<?php
+
+namespace Sabre\CardDAV;
+
+use Sabre\DAV;
+
+/**
+ * Card interface
+ *
+ * Extend the ICard interface to allow your custom nodes to be picked up as
+ * 'Cards'.
+ *
+ * @copyright Copyright (C) fruux GmbH (https://fruux.com/)
+ * @author Evert Pot (http://evertpot.com/)
+ * @license http://sabre.io/license/ Modified BSD License
+ */
+interface ICard extends DAV\IFile {
+
+}
diff --git a/vendor/sabre/dav/lib/CardDAV/IDirectory.php b/vendor/sabre/dav/lib/CardDAV/IDirectory.php
new file mode 100644
index 000000000..d991a1cc8
--- /dev/null
+++ b/vendor/sabre/dav/lib/CardDAV/IDirectory.php
@@ -0,0 +1,20 @@
+<?php
+
+namespace Sabre\CardDAV;
+
+/**
+ * IDirectory interface
+ *
+ * Implement this interface to have an addressbook marked as a 'directory'. A
+ * directory is an (often) global addressbook.
+ *
+ * A full description can be found in the IETF draft:
+ *   - draft-daboo-carddav-directory-gateway
+ *
+ * @copyright Copyright (C) fruux GmbH (https://fruux.com/)
+ * @author Evert Pot (http://evertpot.com/)
+ * @license http://sabre.io/license/ Modified BSD License
+ */
+interface IDirectory extends IAddressBook {
+
+}
diff --git a/vendor/sabre/dav/lib/CardDAV/Plugin.php b/vendor/sabre/dav/lib/CardDAV/Plugin.php
new file mode 100644
index 000000000..b8bded098
--- /dev/null
+++ b/vendor/sabre/dav/lib/CardDAV/Plugin.php
@@ -0,0 +1,871 @@
+<?php
+
+namespace Sabre\CardDAV;
+
+use Sabre\DAV;
+use Sabre\DAV\Exception\ReportNotSupported;
+use Sabre\DAV\Xml\Property\Href;
+use Sabre\DAVACL;
+use Sabre\HTTP;
+use Sabre\HTTP\RequestInterface;
+use Sabre\HTTP\ResponseInterface;
+use Sabre\VObject;
+
+/**
+ * CardDAV plugin
+ *
+ * The CardDAV plugin adds CardDAV functionality to the WebDAV server
+ *
+ * @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 {
+
+    /**
+     * Url to the addressbooks
+     */
+    const ADDRESSBOOK_ROOT = 'addressbooks';
+
+    /**
+     * xml namespace for CardDAV elements
+     */
+    const NS_CARDDAV = 'urn:ietf:params:xml:ns:carddav';
+
+    /**
+     * Add urls to this property to have them automatically exposed as
+     * 'directories' to the user.
+     *
+     * @var array
+     */
+    public $directories = [];
+
+    /**
+     * Server class
+     *
+     * @var Sabre\DAV\Server
+     */
+    protected $server;
+
+    /**
+     * The default PDO storage uses a MySQL MEDIUMBLOB for iCalendar data,
+     * which can hold up to 2^24 = 16777216 bytes. This is plenty. We're
+     * capping it to 10M here.
+     */
+    protected $maxResourceSize = 10000000;
+
+    /**
+     * Initializes the plugin
+     *
+     * @param DAV\Server $server
+     * @return void
+     */
+    function initialize(DAV\Server $server) {
+
+        /* Events */
+        $server->on('propFind',            [$this, 'propFindEarly']);
+        $server->on('propFind',            [$this, 'propFindLate'], 150);
+        $server->on('report',              [$this, 'report']);
+        $server->on('onHTMLActionsPanel',  [$this, 'htmlActionsPanel']);
+        $server->on('beforeWriteContent',  [$this, 'beforeWriteContent']);
+        $server->on('beforeCreateFile',    [$this, 'beforeCreateFile']);
+        $server->on('afterMethod:GET',     [$this, 'httpAfterGet']);
+
+        $server->xml->namespaceMap[self::NS_CARDDAV] = 'card';
+
+        $server->xml->elementMap['{' . self::NS_CARDDAV . '}addressbook-query'] = 'Sabre\\CardDAV\\Xml\\Request\\AddressBookQueryReport';
+        $server->xml->elementMap['{' . self::NS_CARDDAV . '}addressbook-multiget'] = 'Sabre\\CardDAV\\Xml\\Request\\AddressBookMultiGetReport';
+
+        /* Mapping Interfaces to {DAV:}resourcetype values */
+        $server->resourceTypeMapping['Sabre\\CardDAV\\IAddressBook'] = '{' . self::NS_CARDDAV . '}addressbook';
+        $server->resourceTypeMapping['Sabre\\CardDAV\\IDirectory'] = '{' . self::NS_CARDDAV . '}directory';
+
+        /* Adding properties that may never be changed */
+        $server->protectedProperties[] = '{' . self::NS_CARDDAV . '}supported-address-data';
+        $server->protectedProperties[] = '{' . self::NS_CARDDAV . '}max-resource-size';
+        $server->protectedProperties[] = '{' . self::NS_CARDDAV . '}addressbook-home-set';
+        $server->protectedProperties[] = '{' . self::NS_CARDDAV . '}supported-collation-set';
+
+        $server->xml->elementMap['{http://calendarserver.org/ns/}me-card'] = 'Sabre\\DAV\\Xml\\Property\\Href';
+
+        $this->server = $server;
+
+    }
+
+    /**
+     * Returns a list of supported features.
+     *
+     * This is used in the DAV: header in the OPTIONS and PROPFIND requests.
+     *
+     * @return array
+     */
+    function getFeatures() {
+
+        return ['addressbook'];
+
+    }
+
+    /**
+     * 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) {
+
+        $node = $this->server->tree->getNodeForPath($uri);
+        if ($node instanceof IAddressBook || $node instanceof ICard) {
+            return [
+                 '{' . self::NS_CARDDAV . '}addressbook-multiget',
+                 '{' . self::NS_CARDDAV . '}addressbook-query',
+            ];
+        }
+        return [];
+
+    }
+
+
+    /**
+     * Adds all CardDAV-specific properties
+     *
+     * @param DAV\PropFind $propFind
+     * @param DAV\INode $node
+     * @return void
+     */
+    function propFindEarly(DAV\PropFind $propFind, DAV\INode $node) {
+
+        $ns = '{' . self::NS_CARDDAV . '}';
+
+        if ($node instanceof IAddressBook) {
+
+            $propFind->handle($ns . 'max-resource-size', $this->maxResourceSize);
+            $propFind->handle($ns . 'supported-address-data', function() {
+                return new Xml\Property\SupportedAddressData();
+            });
+            $propFind->handle($ns . 'supported-collation-set', function() {
+                return new Xml\Property\SupportedCollationSet();
+            });
+
+        }
+        if ($node instanceof DAVACL\IPrincipal) {
+
+            $path = $propFind->getPath();
+
+            $propFind->handle('{' . self::NS_CARDDAV . '}addressbook-home-set', function() use ($path) {
+                return new Href($this->getAddressBookHomeForPrincipal($path) . '/');
+            });
+
+            if ($this->directories) $propFind->handle('{' . self::NS_CARDDAV . '}directory-gateway', function() {
+                return new Href($this->directories);
+            });
+
+        }
+
+        if ($node instanceof ICard) {
+
+            // The address-data property is not supposed to be a 'real'
+            // property, but in large chunks of the spec it does act as such.
+            // Therefore we simply expose it as a property.
+            $propFind->handle('{' . self::NS_CARDDAV . '}address-data', function() use ($node) {
+                $val = $node->get();
+                if (is_resource($val))
+                    $val = stream_get_contents($val);
+
+                return $val;
+
+            });
+
+        }
+
+    }
+
+    /**
+     * This functions handles REPORT requests specific to CardDAV
+     *
+     * @param string $reportName
+     * @param \DOMNode $dom
+     * @param mixed $path
+     * @return bool
+     */
+    function report($reportName, $dom, $path) {
+
+        switch ($reportName) {
+            case '{' . self::NS_CARDDAV . '}addressbook-multiget' :
+                $this->server->transactionType = 'report-addressbook-multiget';
+                $this->addressbookMultiGetReport($dom);
+                return false;
+            case '{' . self::NS_CARDDAV . '}addressbook-query' :
+                $this->server->transactionType = 'report-addressbook-query';
+                $this->addressBookQueryReport($dom);
+                return false;
+            default :
+                return;
+
+        }
+
+
+    }
+
+    /**
+     * Returns the addressbook home for a given principal
+     *
+     * @param string $principal
+     * @return string
+     */
+    protected function getAddressbookHomeForPrincipal($principal) {
+
+        list(, $principalId) = \Sabre\HTTP\URLUtil::splitPath($principal);
+        return self::ADDRESSBOOK_ROOT . '/' . $principalId;
+
+    }
+
+
+    /**
+     * This function handles the addressbook-multiget REPORT.
+     *
+     * This report is used by the client to fetch the content of a series
+     * of urls. Effectively avoiding a lot of redundant requests.
+     *
+     * @param Xml\Request\AddressBookMultiGetReport $report
+     * @return void
+     */
+    function addressbookMultiGetReport($report) {
+
+        $contentType = $report->contentType;
+        $version = $report->version;
+        if ($version) {
+            $contentType .= '; version=' . $version;
+        }
+
+        $vcardType = $this->negotiateVCard(
+            $contentType
+        );
+
+        $propertyList = [];
+        $paths = array_map(
+            [$this->server, 'calculateUri'],
+            $report->hrefs
+        );
+        foreach ($this->server->getPropertiesForMultiplePaths($paths, $report->properties) as $props) {
+
+            if (isset($props['200']['{' . self::NS_CARDDAV . '}address-data'])) {
+
+                $props['200']['{' . self::NS_CARDDAV . '}address-data'] = $this->convertVCard(
+                    $props[200]['{' . self::NS_CARDDAV . '}address-data'],
+                    $vcardType
+                );
+
+            }
+            $propertyList[] = $props;
+
+        }
+
+        $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($propertyList, $prefer['return'] === 'minimal'));
+
+    }
+
+    /**
+     * This method is triggered before a file gets updated with new content.
+     *
+     * This plugin uses this method to ensure that Card nodes receive valid
+     * vcard data.
+     *
+     * @param string $path
+     * @param DAV\IFile $node
+     * @param resource $data
+     * @param bool $modified Should be set to true, if this event handler
+     *                       changed &$data.
+     * @return void
+     */
+    function beforeWriteContent($path, DAV\IFile $node, &$data, &$modified) {
+
+        if (!$node instanceof ICard)
+            return;
+
+        $this->validateVCard($data, $modified);
+
+    }
+
+    /**
+     * This method is triggered before a new file is created.
+     *
+     * This plugin uses this method to ensure that Card nodes receive valid
+     * vcard data.
+     *
+     * @param string $path
+     * @param resource $data
+     * @param DAV\ICollection $parentNode
+     * @param bool $modified Should be set to true, if this event handler
+     *                       changed &$data.
+     * @return void
+     */
+    function beforeCreateFile($path, &$data, DAV\ICollection $parentNode, &$modified) {
+
+        if (!$parentNode instanceof IAddressBook)
+            return;
+
+        $this->validateVCard($data, $modified);
+
+    }
+
+    /**
+     * Checks if the submitted iCalendar data is in fact, valid.
+     *
+     * An exception is thrown if it's not.
+     *
+     * @param resource|string $data
+     * @param bool $modified Should be set to true, if this event handler
+     *                       changed &$data.
+     * @return void
+     */
+    protected function validateVCard(&$data, &$modified) {
+
+        // If it's a stream, we convert it to a string first.
+        if (is_resource($data)) {
+            $data = stream_get_contents($data);
+        }
+
+        $before = md5($data);
+
+        // Converting the data to unicode, if needed.
+        $data = DAV\StringUtil::ensureUTF8($data);
+
+        if (md5($data) !== $before) $modified = true;
+
+        try {
+
+            // If the data starts with a [, we can reasonably assume we're dealing
+            // with a jCal object.
+            if (substr($data, 0, 1) === '[') {
+                $vobj = VObject\Reader::readJson($data);
+
+                // Converting $data back to iCalendar, as that's what we
+                // technically support everywhere.
+                $data = $vobj->serialize();
+                $modified = true;
+            } else {
+                $vobj = VObject\Reader::read($data);
+            }
+
+        } catch (VObject\ParseException $e) {
+
+            throw new DAV\Exception\UnsupportedMediaType('This resource only supports valid vCard or jCard data. Parse error: ' . $e->getMessage());
+
+        }
+
+        if ($vobj->name !== 'VCARD') {
+            throw new DAV\Exception\UnsupportedMediaType('This collection can only support vcard objects.');
+        }
+
+        if (!isset($vobj->UID)) {
+            // No UID in vcards is invalid, but we'll just add it in anyway.
+            $vobj->add('UID', DAV\UUIDUtil::getUUID());
+            $data = $vobj->serialize();
+            $modified = true;
+        }
+
+        // Destroy circular references to PHP will GC the object.
+        $vobj->destroy();
+    }
+
+
+    /**
+     * This function handles the addressbook-query REPORT
+     *
+     * This report is used by the client to filter an addressbook based on a
+     * complex query.
+     *
+     * @param Xml\Request\AddressBookQueryReport $report
+     * @return void
+     */
+    protected function addressbookQueryReport($report) {
+
+        $depth = $this->server->getHTTPDepth(0);
+
+        if ($depth == 0) {
+            $candidateNodes = [
+                $this->server->tree->getNodeForPath($this->server->getRequestUri())
+            ];
+            if (!$candidateNodes[0] instanceof ICard) {
+                throw new ReportNotSupported('The addressbook-query report is not supported on this url with Depth: 0');
+            }
+        } else {
+            $candidateNodes = $this->server->tree->getChildren($this->server->getRequestUri());
+        }
+
+        $contentType = $report->contentType;
+        if ($report->version) {
+            $contentType .= '; version=' . $report->version;
+        }
+
+        $vcardType = $this->negotiateVCard(
+            $contentType
+        );
+
+        $validNodes = [];
+        foreach ($candidateNodes as $node) {
+
+            if (!$node instanceof ICard)
+                continue;
+
+            $blob = $node->get();
+            if (is_resource($blob)) {
+                $blob = stream_get_contents($blob);
+            }
+
+            if (!$this->validateFilters($blob, $report->filters, $report->test)) {
+                continue;
+            }
+
+            $validNodes[] = $node;
+
+            if ($report->limit && $report->limit <= count($validNodes)) {
+                // We hit the maximum number of items, we can stop now.
+                break;
+            }
+
+        }
+
+        $result = [];
+        foreach ($validNodes as $validNode) {
+
+            if ($depth == 0) {
+                $href = $this->server->getRequestUri();
+            } else {
+                $href = $this->server->getRequestUri() . '/' . $validNode->getName();
+            }
+
+            list($props) = $this->server->getPropertiesForPath($href, $report->properties, 0);
+
+            if (isset($props[200]['{' . self::NS_CARDDAV . '}address-data'])) {
+
+                $props[200]['{' . self::NS_CARDDAV . '}address-data'] = $this->convertVCard(
+                    $props[200]['{' . self::NS_CARDDAV . '}address-data'],
+                    $vcardType
+                );
+
+            }
+            $result[] = $props;
+
+        }
+
+        $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'));
+
+    }
+
+    /**
+     * Validates if a vcard makes it throught a list of filters.
+     *
+     * @param string $vcardData
+     * @param array $filters
+     * @param string $test anyof or allof (which means OR or AND)
+     * @return bool
+     */
+    function validateFilters($vcardData, array $filters, $test) {
+
+
+        if (!$filters) return true;
+        $vcard = VObject\Reader::read($vcardData);
+
+        foreach ($filters as $filter) {
+
+            $isDefined = isset($vcard->{$filter['name']});
+            if ($filter['is-not-defined']) {
+                if ($isDefined) {
+                    $success = false;
+                } else {
+                    $success = true;
+                }
+            } elseif ((!$filter['param-filters'] && !$filter['text-matches']) || !$isDefined) {
+
+                // We only need to check for existence
+                $success = $isDefined;
+
+            } else {
+
+                $vProperties = $vcard->select($filter['name']);
+
+                $results = [];
+                if ($filter['param-filters']) {
+                    $results[] = $this->validateParamFilters($vProperties, $filter['param-filters'], $filter['test']);
+                }
+                if ($filter['text-matches']) {
+                    $texts = [];
+                    foreach ($vProperties as $vProperty)
+                        $texts[] = $vProperty->getValue();
+
+                    $results[] = $this->validateTextMatches($texts, $filter['text-matches'], $filter['test']);
+                }
+
+                if (count($results) === 1) {
+                    $success = $results[0];
+                } else {
+                    if ($filter['test'] === 'anyof') {
+                        $success = $results[0] || $results[1];
+                    } else {
+                        $success = $results[0] && $results[1];
+                    }
+                }
+
+            } // else
+
+            // There are two conditions where we can already determine whether
+            // or not this filter succeeds.
+            if ($test === 'anyof' && $success) {
+
+                // Destroy circular references to PHP will GC the object.
+                $vcard->destroy();
+
+                return true;
+            }
+            if ($test === 'allof' && !$success) {
+
+                // Destroy circular references to PHP will GC the object.
+                $vcard->destroy();
+
+                return false;
+            }
+
+        } // foreach
+
+
+        // Destroy circular references to PHP will GC the object.
+        $vcard->destroy();
+
+        // If we got all the way here, it means we haven't been able to
+        // determine early if the test failed or not.
+        //
+        // This implies for 'anyof' that the test failed, and for 'allof' that
+        // we succeeded. Sounds weird, but makes sense.
+        return $test === 'allof';
+
+    }
+
+    /**
+     * Validates if a param-filter can be applied to a specific property.
+     *
+     * @todo currently we're only validating the first parameter of the passed
+     *       property. Any subsequence parameters with the same name are
+     *       ignored.
+     * @param array $vProperties
+     * @param array $filters
+     * @param string $test
+     * @return bool
+     */
+    protected function validateParamFilters(array $vProperties, array $filters, $test) {
+
+        foreach ($filters as $filter) {
+
+            $isDefined = false;
+            foreach ($vProperties as $vProperty) {
+                $isDefined = isset($vProperty[$filter['name']]);
+                if ($isDefined) break;
+            }
+
+            if ($filter['is-not-defined']) {
+                if ($isDefined) {
+                    $success = false;
+                } else {
+                    $success = true;
+                }
+
+            // If there's no text-match, we can just check for existence
+            } elseif (!$filter['text-match'] || !$isDefined) {
+
+                $success = $isDefined;
+
+            } else {
+
+                $success = false;
+                foreach ($vProperties as $vProperty) {
+                    // If we got all the way here, we'll need to validate the
+                    // text-match filter.
+                    $success = DAV\StringUtil::textMatch($vProperty[$filter['name']]->getValue(), $filter['text-match']['value'], $filter['text-match']['collation'], $filter['text-match']['match-type']);
+                    if ($success) break;
+                }
+                if ($filter['text-match']['negate-condition']) {
+                    $success = !$success;
+                }
+
+            } // else
+
+            // There are two conditions where we can already determine whether
+            // or not this filter succeeds.
+            if ($test === 'anyof' && $success) {
+                return true;
+            }
+            if ($test === 'allof' && !$success) {
+                return false;
+            }
+
+        }
+
+        // If we got all the way here, it means we haven't been able to
+        // determine early if the test failed or not.
+        //
+        // This implies for 'anyof' that the test failed, and for 'allof' that
+        // we succeeded. Sounds weird, but makes sense.
+        return $test === 'allof';
+
+    }
+
+    /**
+     * Validates if a text-filter can be applied to a specific property.
+     *
+     * @param array $texts
+     * @param array $filters
+     * @param string $test
+     * @return bool
+     */
+    protected function validateTextMatches(array $texts, array $filters, $test) {
+
+        foreach ($filters as $filter) {
+
+            $success = false;
+            foreach ($texts as $haystack) {
+                $success = DAV\StringUtil::textMatch($haystack, $filter['value'], $filter['collation'], $filter['match-type']);
+
+                // Breaking on the first match
+                if ($success) break;
+            }
+            if ($filter['negate-condition']) {
+                $success = !$success;
+            }
+
+            if ($success && $test === 'anyof')
+                return true;
+
+            if (!$success && $test == 'allof')
+                return false;
+
+
+        }
+
+        // If we got all the way here, it means we haven't been able to
+        // determine early if the test failed or not.
+        //
+        // This implies for 'anyof' that the test failed, and for 'allof' that
+        // we succeeded. Sounds weird, but makes sense.
+        return $test === 'allof';
+
+    }
+
+    /**
+     * This event is triggered when fetching properties.
+     *
+     * This event is scheduled late in the process, after most work for
+     * propfind has been done.
+     *
+     * @param DAV\PropFind $propFind
+     * @param DAV\INode $node
+     * @return void
+     */
+    function propFindLate(DAV\PropFind $propFind, DAV\INode $node) {
+
+        // If the request was made using the SOGO connector, we must rewrite
+        // the content-type property. By default SabreDAV will send back
+        // text/x-vcard; charset=utf-8, but for SOGO we must strip that last
+        // part.
+        if (strpos($this->server->httpRequest->getHeader('User-Agent'), 'Thunderbird') === false) {
+            return;
+        }
+        $contentType = $propFind->get('{DAV:}getcontenttype');
+        list($part) = explode(';', $contentType);
+        if ($part === 'text/x-vcard' || $part === 'text/vcard') {
+            $propFind->set('{DAV:}getcontenttype', 'text/x-vcard');
+        }
+
+    }
+
+    /**
+     * This method is used to generate HTML output for the
+     * Sabre\DAV\Browser\Plugin. This allows us to generate an interface users
+     * can use to create new addressbooks.
+     *
+     * @param DAV\INode $node
+     * @param string $output
+     * @return bool
+     */
+    function htmlActionsPanel(DAV\INode $node, &$output) {
+
+        if (!$node instanceof AddressBookHome)
+            return;
+
+        $output .= '<tr><td colspan="2"><form method="post" action="">
+            <h3>Create new address book</h3>
+            <input type="hidden" name="sabreAction" value="mkcol" />
+            <input type="hidden" name="resourceType" value="{DAV:}collection,{' . self::NS_CARDDAV . '}addressbook" />
+            <label>Name (uri):</label> <input type="text" name="name" /><br />
+            <label>Display name:</label> <input type="text" name="{DAV:}displayname" /><br />
+            <input type="submit" value="create" />
+            </form>
+            </td></tr>';
+
+        return false;
+
+    }
+
+    /**
+     * This event is triggered after GET requests.
+     *
+     * This is used to transform data into jCal, if this was requested.
+     *
+     * @param RequestInterface $request
+     * @param ResponseInterface $response
+     * @return void
+     */
+    function httpAfterGet(RequestInterface $request, ResponseInterface $response) {
+
+        if (strpos($response->getHeader('Content-Type'), 'text/vcard') === false) {
+            return;
+        }
+
+        $target = $this->negotiateVCard($request->getHeader('Accept'), $mimeType);
+
+        $newBody = $this->convertVCard(
+            $response->getBody(),
+            $target
+        );
+
+        $response->setBody($newBody);
+        $response->setHeader('Content-Type', $mimeType . '; charset=utf-8');
+        $response->setHeader('Content-Length', strlen($newBody));
+
+    }
+
+    /**
+     * This helper function performs the content-type negotiation for vcards.
+     *
+     * It will return one of the following strings:
+     * 1. vcard3
+     * 2. vcard4
+     * 3. jcard
+     *
+     * It defaults to vcard3.
+     *
+     * @param string $input
+     * @param string $mimeType
+     * @return string
+     */
+    protected function negotiateVCard($input, &$mimeType = null) {
+
+        $result = HTTP\Util::negotiate(
+            $input,
+            [
+                // Most often used mime-type. Version 3
+                'text/x-vcard',
+                // The correct standard mime-type. Defaults to version 3 as
+                // well.
+                'text/vcard',
+                // vCard 4
+                'text/vcard; version=4.0',
+                // vCard 3
+                'text/vcard; version=3.0',
+                // jCard
+                'application/vcard+json',
+            ]
+        );
+
+        $mimeType = $result;
+        switch ($result) {
+
+            default :
+            case 'text/x-vcard' :
+            case 'text/vcard' :
+            case 'text/vcard; version=3.0' :
+                $mimeType = 'text/vcard';
+                return 'vcard3';
+            case 'text/vcard; version=4.0' :
+                return 'vcard4';
+            case 'application/vcard+json' :
+                return 'jcard';
+
+        // @codeCoverageIgnoreStart
+        }
+        // @codeCoverageIgnoreEnd
+
+    }
+
+    /**
+     * Converts a vcard blob to a different version, or jcard.
+     *
+     * @param string $data
+     * @param string $target
+     * @return string
+     */
+    protected function convertVCard($data, $target) {
+
+        $data = VObject\Reader::read($data);
+        switch ($target) {
+            default :
+            case 'vcard3' :
+                $data = $data->convert(VObject\Document::VCARD30);
+                $newResult = $data->serialize();
+                break;
+            case 'vcard4' :
+                $data = $data->convert(VObject\Document::VCARD40);
+                $newResult = $data->serialize();
+                break;
+            case 'jcard' :
+                $data = $data->convert(VObject\Document::VCARD40);
+                $newResult = json_encode($data->jsonSerialize());
+                break;
+
+        }
+        // Destroy circular references to PHP will GC the object.
+        $data->destroy();
+
+        return $newResult;
+
+    }
+
+    /**
+     * Returns a plugin name.
+     *
+     * Using this name other plugins will be able to access other plugins
+     * using DAV\Server::getPlugin
+     *
+     * @return string
+     */
+    function getPluginName() {
+
+        return 'carddav';
+
+    }
+
+    /**
+     * 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 CardDAV (rfc6352)',
+            'link'        => 'http://sabre.io/dav/carddav/',
+        ];
+
+    }
+
+}
diff --git a/vendor/sabre/dav/lib/CardDAV/VCFExportPlugin.php b/vendor/sabre/dav/lib/CardDAV/VCFExportPlugin.php
new file mode 100644
index 000000000..de8b3bb84
--- /dev/null
+++ b/vendor/sabre/dav/lib/CardDAV/VCFExportPlugin.php
@@ -0,0 +1,152 @@
+<?php
+
+namespace Sabre\CardDAV;
+
+use Sabre\DAV;
+use Sabre\VObject;
+use Sabre\HTTP\RequestInterface;
+use Sabre\HTTP\ResponseInterface;
+
+/**
+ * VCF Exporter
+ *
+ * This plugin adds the ability to export entire address books as .vcf files.
+ * This is useful for clients that don't support CardDAV yet. They often do
+ * support vcf files.
+ *
+ * @copyright Copyright (C) fruux GmbH (https://fruux.com/)
+ * @author Evert Pot (http://evertpot.com/)
+ * @author Thomas Tanghus (http://tanghus.net/)
+ * @license http://sabre.io/license/ Modified BSD License
+ */
+class VCFExportPlugin extends DAV\ServerPlugin {
+
+    /**
+     * Reference to Server class
+     *
+     * @var Sabre\DAV\Server
+     */
+    protected $server;
+
+    /**
+     * Initializes the plugin and registers event handlers
+     *
+     * @param DAV\Server $server
+     * @return void
+     */
+    function initialize(DAV\Server $server) {
+
+        $this->server = $server;
+        $this->server->on('method:GET', [$this, 'httpGet'], 90);
+        $server->on('browserButtonActions', function($path, $node, &$actions) {
+            if ($node instanceof IAddressBook) {
+                $actions .= '<a href="' . htmlspecialchars($path, ENT_QUOTES, 'UTF-8') . '?export"><span class="oi" data-glyph="book"></span></a>';
+            }
+        });
+    }
+
+    /**
+     * Intercepts GET requests on addressbook urls ending with ?export.
+     *
+     * @param RequestInterface $request
+     * @param ResponseInterface $response
+     * @return bool
+     */
+    function httpGet(RequestInterface $request, ResponseInterface $response) {
+
+        $queryParams = $request->getQueryParameters();
+        if (!array_key_exists('export', $queryParams)) return;
+
+        $path = $request->getPath();
+
+        $node = $this->server->tree->getNodeForPath($path);
+
+        if (!($node instanceof IAddressBook)) return;
+
+        $this->server->transactionType = 'get-addressbook-export';
+
+        // Checking ACL, if available.
+        if ($aclPlugin = $this->server->getPlugin('acl')) {
+            $aclPlugin->checkPrivileges($path, '{DAV:}read');
+        }
+
+        $response->setHeader('Content-Type', 'text/directory');
+        $response->setStatus(200);
+
+        $nodes = $this->server->getPropertiesForPath($path, [
+            '{' . Plugin::NS_CARDDAV . '}address-data',
+        ], 1);
+
+        $response->setBody($this->generateVCF($nodes));
+
+        // Returning false to break the event chain
+        return false;
+
+    }
+
+    /**
+     * Merges all vcard objects, and builds one big vcf export
+     *
+     * @param array $nodes
+     * @return string
+     */
+    function generateVCF(array $nodes) {
+
+        $output = "";
+
+        foreach ($nodes as $node) {
+
+            if (!isset($node[200]['{' . Plugin::NS_CARDDAV . '}address-data'])) {
+                continue;
+            }
+            $nodeData = $node[200]['{' . Plugin::NS_CARDDAV . '}address-data'];
+
+            // Parsing this node so VObject can clean up the output.
+            $vcard = VObject\Reader::read($nodeData);
+            $output .= $vcard->serialize();
+
+            // Destroy circular references to PHP will GC the object.
+            $vcard->destroy();
+
+        }
+
+        return $output;
+
+    }
+
+    /**
+     * 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 'vcf-export';
+
+    }
+
+    /**
+     * 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 the ability to export CardDAV addressbooks as a single vCard file.',
+            'link'        => 'http://sabre.io/dav/vcf-export-plugin/',
+        ];
+
+    }
+
+}
diff --git a/vendor/sabre/dav/lib/CardDAV/Xml/Filter/AddressData.php b/vendor/sabre/dav/lib/CardDAV/Xml/Filter/AddressData.php
new file mode 100644
index 000000000..34028db85
--- /dev/null
+++ b/vendor/sabre/dav/lib/CardDAV/Xml/Filter/AddressData.php
@@ -0,0 +1,59 @@
+<?php
+
+namespace Sabre\CardDAV\Xml\Filter;
+
+use Sabre\Xml\Reader;
+use Sabre\Xml\XmlDeserializable;
+
+/**
+ * AddressData parser.
+ *
+ * This class parses the {urn:ietf:params:xml:ns:carddav}address-data XML
+ * element, as defined in:
+ *
+ * http://tools.ietf.org/html/rfc6352#section-10.4
+ *
+ * This element is used in two distinct places, but this one specifically
+ * encodes the address-data element as it appears in the addressbook-query
+ * adressbook-multiget REPORT requests.
+ *
+ * @copyright Copyright (C) fruux GmbH (https://fruux.com/)
+ * @author Evert Pot (http://www.rooftopsolutions.nl/)
+ * @license http://sabre.io/license/ Modified BSD License
+ */
+class AddressData 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) {
+
+        $result = [
+            'contentType' => $reader->getAttribute('content-type') ?: 'text/vcard',
+            'version'     => $reader->getAttribute('version') ?: '3.0',
+        ];
+
+        $reader->next();
+        return $result;
+
+    }
+
+}
diff --git a/vendor/sabre/dav/lib/CardDAV/Xml/Filter/ParamFilter.php b/vendor/sabre/dav/lib/CardDAV/Xml/Filter/ParamFilter.php
new file mode 100644
index 000000000..9646ae3e6
--- /dev/null
+++ b/vendor/sabre/dav/lib/CardDAV/Xml/Filter/ParamFilter.php
@@ -0,0 +1,89 @@
+<?php
+
+namespace Sabre\CardDAV\Xml\Filter;
+
+use Sabre\Xml\Element;
+use Sabre\Xml\Reader;
+use Sabre\DAV\Exception\BadRequest;
+use Sabre\CardDAV\Plugin;
+
+/**
+ * ParamFilter parser.
+ *
+ * This class parses the {urn:ietf:params:xml:ns:carddav}param-filter XML
+ * element, as defined in:
+ *
+ * http://tools.ietf.org/html/rfc6352#section-10.5.2
+ *
+ * The result will be spit out as an array.
+ *
+ * @copyright Copyright (C) fruux GmbH (https://fruux.com/)
+ * @author Evert Pot (http://evertpot.com/)
+ * @license http://sabre.io/license/ Modified BSD License
+ */
+abstract class ParamFilter implements Element {
+
+    /**
+     * 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 = [
+            'name'           => null,
+            'is-not-defined' => false,
+            'text-match'     => null,
+        ];
+
+        $att = $reader->parseAttributes();
+        $result['name'] = $att['name'];
+
+        $elems = $reader->parseInnerTree();
+
+        if (is_array($elems)) foreach ($elems as $elem) {
+
+            switch ($elem['name']) {
+
+                case '{' . Plugin::NS_CARDDAV . '}is-not-defined' :
+                    $result['is-not-defined'] = true;
+                    break;
+                case '{' . Plugin::NS_CARDDAV . '}text-match' :
+                    $matchType = isset($elem['attributes']['match-type']) ? $elem['attributes']['match-type'] : 'contains';
+
+                    if (!in_array($matchType, ['contains', 'equals', 'starts-with', 'ends-with'])) {
+                        throw new BadRequest('Unknown match-type: ' . $matchType);
+                    }
+                    $result['text-match'] = [
+                        'negate-condition' => isset($elem['attributes']['negate-condition']) && $elem['attributes']['negate-condition'] === 'yes',
+                        'collation'        => isset($elem['attributes']['collation']) ? $elem['attributes']['collation'] : 'i;unicode-casemap',
+                        'value'            => $elem['value'],
+                        'match-type'       => $matchType,
+                    ];
+                    break;
+
+            }
+
+        }
+
+        return $result;
+
+    }
+
+}
diff --git a/vendor/sabre/dav/lib/CardDAV/Xml/Filter/PropFilter.php b/vendor/sabre/dav/lib/CardDAV/Xml/Filter/PropFilter.php
new file mode 100644
index 000000000..c162da160
--- /dev/null
+++ b/vendor/sabre/dav/lib/CardDAV/Xml/Filter/PropFilter.php
@@ -0,0 +1,98 @@
+<?php
+
+namespace Sabre\CardDAV\Xml\Filter;
+
+use Sabre\Xml\Reader;
+use Sabre\Xml\XmlDeserializable;
+use Sabre\DAV\Exception\BadRequest;
+use Sabre\CardDAV\Plugin;
+
+/**
+ * PropFilter parser.
+ *
+ * This class parses the {urn:ietf:params:xml:ns:carddav}prop-filter XML
+ * element, as defined in:
+ *
+ * http://tools.ietf.org/html/rfc6352#section-10.5.1
+ *
+ * The result will be spit out as an array.
+ *
+ * @copyright Copyright (C) fruux GmbH (https://fruux.com/)
+ * @author Evert Pot (http://evertpot.com/)
+ * @license http://sabre.io/license/ Modified BSD License
+ */
+class PropFilter 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) {
+
+        $result = [
+            'name'           => null,
+            'test'           => 'anyof',
+            'is-not-defined' => false,
+            'param-filters'  => [],
+            'text-matches'   => [],
+        ];
+
+        $att = $reader->parseAttributes();
+        $result['name'] = $att['name'];
+
+        if (isset($att['test']) && $att['test'] === 'allof') {
+            $result['test'] = 'allof';
+        }
+
+        $elems = $reader->parseInnerTree();
+
+        if (is_array($elems)) foreach ($elems as $elem) {
+
+            switch ($elem['name']) {
+
+                case '{' . Plugin::NS_CARDDAV . '}param-filter' :
+                    $result['param-filters'][] = $elem['value'];
+                    break;
+                case '{' . Plugin::NS_CARDDAV . '}is-not-defined' :
+                    $result['is-not-defined'] = true;
+                    break;
+                case '{' . Plugin::NS_CARDDAV . '}text-match' :
+                    $matchType = isset($elem['attributes']['match-type']) ? $elem['attributes']['match-type'] : 'contains';
+
+                    if (!in_array($matchType, ['contains', 'equals', 'starts-with', 'ends-with'])) {
+                        throw new BadRequest('Unknown match-type: ' . $matchType);
+                    }
+                    $result['text-matches'][] = [
+                        'negate-condition' => isset($elem['attributes']['negate-condition']) && $elem['attributes']['negate-condition'] === 'yes',
+                        'collation'        => isset($elem['attributes']['collation']) ? $elem['attributes']['collation'] : 'i;unicode-casemap',
+                        'value'            => $elem['value'],
+                        'match-type'       => $matchType,
+                    ];
+                    break;
+
+            }
+
+        }
+
+        return $result;
+
+    }
+
+}
diff --git a/vendor/sabre/dav/lib/CardDAV/Xml/Property/SupportedAddressData.php b/vendor/sabre/dav/lib/CardDAV/Xml/Property/SupportedAddressData.php
new file mode 100644
index 000000000..6ff57b6e3
--- /dev/null
+++ b/vendor/sabre/dav/lib/CardDAV/Xml/Property/SupportedAddressData.php
@@ -0,0 +1,83 @@
+<?php
+
+namespace Sabre\CardDAV\Xml\Property;
+
+use Sabre\Xml\Writer;
+use Sabre\Xml\XmlSerializable;
+use Sabre\CardDAV\Plugin;
+
+/**
+ * Supported-address-data property
+ *
+ * This property is a representation of the supported-address-data property
+ * in the CardDAV namespace.
+ *
+ * This property is defined in:
+ *
+ * http://tools.ietf.org/html/rfc6352#section-6.2.2
+ *
+ * @copyright Copyright (C) fruux GmbH (https://fruux.com/)
+ * @author Evert Pot (http://evertpot.com/)
+ * @license http://sabre.io/license/ Modified BSD License
+ */
+class SupportedAddressData implements XmlSerializable {
+
+    /**
+     * supported versions
+     *
+     * @var array
+     */
+    protected $supportedData = [];
+
+    /**
+     * Creates the property
+     *
+     * @param array|null $supportedData
+     */
+    function __construct(array $supportedData = null) {
+
+        if (is_null($supportedData)) {
+            $supportedData = [
+                ['contentType' => 'text/vcard', 'version' => '3.0'],
+                ['contentType' => 'text/vcard', 'version' => '4.0'],
+                ['contentType' => 'application/vcard+json', 'version' => '4.0'],
+            ];
+        }
+
+        $this->supportedData = $supportedData;
+
+    }
+
+    /**
+     * 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->supportedData as $supported) {
+            $writer->startElement('{' . Plugin::NS_CARDDAV . '}address-data-type');
+            $writer->writeAttributes([
+                'content-type' => $supported['contentType'],
+                'version'      => $supported['version']
+                ]);
+            $writer->endElement(); // address-data-type
+        }
+
+    }
+
+}
diff --git a/vendor/sabre/dav/lib/CardDAV/Xml/Property/SupportedCollationSet.php b/vendor/sabre/dav/lib/CardDAV/Xml/Property/SupportedCollationSet.php
new file mode 100644
index 000000000..1fc064900
--- /dev/null
+++ b/vendor/sabre/dav/lib/CardDAV/Xml/Property/SupportedCollationSet.php
@@ -0,0 +1,47 @@
+<?php
+
+namespace Sabre\CardDAV\Xml\Property;
+
+use Sabre\Xml\Writer;
+use Sabre\Xml\XmlSerializable;
+
+/**
+ * supported-collation-set property
+ *
+ * This property is a representation of the supported-collation-set property
+ * in the CardDAV namespace.
+ *
+ * @copyright Copyright (C) fruux GmbH (https://fruux.com/)
+ * @author Evert Pot (http://evertpot.com/)
+ * @license http://sabre.io/license/ Modified BSD License
+ */
+class SupportedCollationSet 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) {
+
+        foreach (['i;ascii-casemap', 'i;octet', 'i;unicode-casemap'] as $coll) {
+            $writer->writeElement('{urn:ietf:params:xml:ns:carddav}supported-collation', $coll);
+        }
+
+    }
+
+}
diff --git a/vendor/sabre/dav/lib/CardDAV/Xml/Request/AddressBookMultiGetReport.php b/vendor/sabre/dav/lib/CardDAV/Xml/Request/AddressBookMultiGetReport.php
new file mode 100644
index 000000000..c97c5eb4f
--- /dev/null
+++ b/vendor/sabre/dav/lib/CardDAV/Xml/Request/AddressBookMultiGetReport.php
@@ -0,0 +1,113 @@
+<?php
+
+namespace Sabre\CardDAV\Xml\Request;
+
+use Sabre\CardDAV\Plugin;
+use Sabre\Uri;
+use Sabre\Xml\Reader;
+use Sabre\Xml\XmlDeserializable;
+
+/**
+ * AddressBookMultiGetReport request parser.
+ *
+ * This class parses the {urn:ietf:params:xml:ns:carddav}addressbook-multiget
+ * REPORT, as defined in:
+ *
+ * http://tools.ietf.org/html/rfc6352#section-8.7
+ *
+ * @copyright Copyright (C) fruux GmbH (https://fruux.com/)
+ * @author Evert Pot (http://www.rooftopsolutions.nl/)
+ * @license http://sabre.io/license/ Modified BSD License
+ */
+class AddressBookMultiGetReport implements XmlDeserializable {
+
+    /**
+     * An array with requested properties.
+     *
+     * @var array
+     */
+    public $properties;
+
+    /**
+     * This is an array with the urls that are being requested.
+     *
+     * @var array
+     */
+    public $hrefs;
+
+    /**
+     * The mimetype of the content that should be returend. Usually
+     * text/vcard.
+     *
+     * @var string
+     */
+    public $contentType = null;
+
+    /**
+     * The version of vcard data that should be returned. Usually 3.0,
+     * referring to vCard 3.0.
+     *
+     * @var string
+     */
+    public $version = null;
+
+    /**
+     * 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([
+            '{urn:ietf:params:xml:ns:carddav}address-data' => 'Sabre\\CardDAV\\Xml\\Filter\\AddressData',
+            '{DAV:}prop'                                   => 'Sabre\\Xml\\Element\\KeyValue',
+        ]);
+
+        $newProps = [
+            'hrefs'      => [],
+            'properties' => []
+        ];
+
+        foreach ($elems as $elem) {
+
+            switch ($elem['name']) {
+
+                case '{DAV:}prop' :
+                    $newProps['properties'] = array_keys($elem['value']);
+                    if (isset($elem['value']['{' . Plugin::NS_CARDDAV . '}address-data'])) {
+                        $newProps += $elem['value']['{' . Plugin::NS_CARDDAV . '}address-data'];
+                    }
+                    break;
+                case '{DAV:}href' :
+                    $newProps['hrefs'][] = Uri\resolve($reader->contextUri, $elem['value']);
+                    break;
+
+            }
+
+        }
+
+        $obj = new self();
+        foreach ($newProps as $key => $value) {
+            $obj->$key = $value;
+        }
+        return $obj;
+
+    }
+
+}
diff --git a/vendor/sabre/dav/lib/CardDAV/Xml/Request/AddressBookQueryReport.php b/vendor/sabre/dav/lib/CardDAV/Xml/Request/AddressBookQueryReport.php
new file mode 100644
index 000000000..a68ac5800
--- /dev/null
+++ b/vendor/sabre/dav/lib/CardDAV/Xml/Request/AddressBookQueryReport.php
@@ -0,0 +1,192 @@
+<?php
+
+namespace Sabre\CardDAV\Xml\Request;
+
+use Sabre\Xml\Reader;
+use Sabre\Xml\XmlDeserializable;
+use Sabre\DAV\Exception\BadRequest;
+use Sabre\CardDAV\Plugin;
+
+/**
+ * AddressBookQueryReport request parser.
+ *
+ * This class parses the {urn:ietf:params:xml:ns:carddav}addressbook-query
+ * REPORT, as defined in:
+ *
+ * http://tools.ietf.org/html/rfc6352#section-8.6
+ *
+ * @copyright Copyright (C) fruux GmbH (https://fruux.com/)
+ * @author Evert Pot (http://www.rooftopsolutions.nl/)
+ * @license http://sabre.io/license/ Modified BSD License
+ */
+class AddressBookQueryReport implements XmlDeserializable {
+
+    /**
+     * An array with requested properties.
+     *
+     * @var array
+     */
+    public $properties;
+
+    /**
+     * List of property/component filters.
+     *
+     * This is an array with filters. Every item is a property filter. Every
+     * property filter has the following keys:
+     *   * name - name of the component to filter on
+     *   * test - anyof or allof
+     *   * is-not-defined - Test for non-existence
+     *   * param-filters - A list of parameter filters on the property
+     *   * text-matches - A list of text values the filter needs to match
+     *
+     * Each param-filter has the following keys:
+     *   * name - name of the parameter
+     *   * is-not-defined - Test for non-existence
+     *   * text-match - Match the parameter value
+     *
+     * Each text-match in property filters, and the single text-match in
+     * param-filters have the following keys:
+     *
+     *   * value - value to match
+     *   * match-type - contains, starts-with, ends-with, equals
+     *   * negate-condition - Do the opposite match
+     *   * collation - Usually i;unicode-casemap
+     *
+     * @var array
+     */
+    public $filters;
+
+    /**
+     * The number of results the client wants
+     *
+     * null means it wasn't specified, which in most cases means 'all results'.
+     *
+     * @var int|null
+     */
+    public $limit;
+
+    /**
+     * Either 'anyof' or 'allof'
+     *
+     * @var string
+     */
+    public $test;
+
+    /**
+     * The mimetype of the content that should be returend. Usually
+     * text/vcard.
+     *
+     * @var string
+     */
+    public $contentType = null;
+
+    /**
+     * The version of vcard data that should be returned. Usually 3.0,
+     * referring to vCard 3.0.
+     *
+     * @var string
+     */
+    public $version = null;
+
+
+    /**
+     * 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) {
+
+        $elems = (array)$reader->parseInnerTree([
+            '{urn:ietf:params:xml:ns:carddav}prop-filter'  => 'Sabre\\CardDAV\\Xml\\Filter\\PropFilter',
+            '{urn:ietf:params:xml:ns:carddav}param-filter' => 'Sabre\\CardDAV\\Xml\\Filter\\ParamFilter',
+            '{urn:ietf:params:xml:ns:carddav}address-data' => 'Sabre\\CardDAV\\Xml\\Filter\\AddressData',
+            '{DAV:}prop'                                   => 'Sabre\\Xml\\Element\\KeyValue',
+        ]);
+
+        $newProps = [
+            'filters'    => null,
+            'properties' => [],
+            'test'       => 'anyof',
+            'limit'      => null,
+        ];
+
+        if (!is_array($elems)) $elems = [];
+
+        foreach ($elems as $elem) {
+
+            switch ($elem['name']) {
+
+                case '{DAV:}prop' :
+                    $newProps['properties'] = array_keys($elem['value']);
+                    if (isset($elem['value']['{' . Plugin::NS_CARDDAV . '}address-data'])) {
+                        $newProps += $elem['value']['{' . Plugin::NS_CARDDAV . '}address-data'];
+                    }
+                    break;
+                case '{' . Plugin::NS_CARDDAV . '}filter' :
+
+                    if (!is_null($newProps['filters'])) {
+                        throw new BadRequest('You can only include 1 {' . Plugin::NS_CARDDAV . '}filter element');
+                    }
+                    if (isset($elem['attributes']['test'])) {
+                        $newProps['test'] = $elem['attributes']['test'];
+                        if ($newProps['test'] !== 'allof' && $newProps['test'] !== 'anyof') {
+                            throw new BadRequest('The "test" attribute must be one of "allof" or "anyof"');
+                        }
+                    }
+
+                    $newProps['filters'] = [];
+                    foreach ((array)$elem['value'] as $subElem) {
+                        if ($subElem['name'] === '{' . Plugin::NS_CARDDAV . '}prop-filter') {
+                            $newProps['filters'][] = $subElem['value'];
+                        }
+                    }
+                    break;
+                case '{' . Plugin::NS_CARDDAV . '}limit' :
+                    foreach ($elem['value'] as $child) {
+                        if ($child['name'] === '{' . Plugin::NS_CARDDAV . '}nresults') {
+                            $newProps['limit'] = (int)$child['value'];
+                        }
+                    }
+                    break;
+
+            }
+
+        }
+
+        if (is_null($newProps['filters'])) {
+            /*
+             * We are supposed to throw this error, but KDE sometimes does not
+             * include the filter element, and we need to treat it as if no
+             * filters are supplied
+             */
+            //throw new BadRequest('The {' . Plugin::NS_CARDDAV . '}filter element is required for this request');
+            $newProps['filters'] = [];
+
+        }
+
+        $obj = new self();
+        foreach ($newProps as $key => $value) {
+            $obj->$key = $value;
+        }
+
+        return $obj;
+
+    }
+
+}