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

17 files changed, 1987 insertions, 0 deletions

diff --git a/vendor/sabre/dav/lib/DAV/Xml/Element/Prop.php b/vendor/sabre/dav/lib/DAV/Xml/Element/Prop.php
new file mode 100644
index 000000000..db5332c50
--- /dev/null
+++ b/vendor/sabre/dav/lib/DAV/Xml/Element/Prop.php
@@ -0,0 +1,116 @@
+<?php
+
+namespace Sabre\DAV\Xml\Element;
+
+use Sabre\DAV\Xml\Property\Complex;
+use Sabre\Xml\XmlDeserializable;
+use Sabre\Xml\Reader;
+
+/**
+ * This class is responsible for decoding the {DAV:}prop element as it appears
+ * in {DAV:}property-update.
+ *
+ * This class doesn't return an instance of itself. It just returns a
+ * key->value array.
+ *
+ * @copyright Copyright (C) fruux GmbH (https://fruux.com/)
+ * @author Evert Pot (http://evertpot.com/)
+ * @license http://sabre.io/license/ Modified BSD License
+ */
+class Prop implements XmlDeserializable {
+
+    /**
+     * The deserialize method is called during xml parsing.
+     *
+     * This method is called statictly, this is because in theory this method
+     * may be used as a type of constructor, or factory method.
+     *
+     * Often you want to return an instance of the current class, but you are
+     * free to return other data as well.
+     *
+     * You are responsible for advancing the reader to the next element. Not
+     * doing anything will result in a never-ending loop.
+     *
+     * If you just want to skip parsing for this element altogether, you can
+     * just call $reader->next();
+     *
+     * $reader->parseInnerTree() will parse the entire sub-tree, and advance to
+     * the next element.
+     *
+     * @param Reader $reader
+     * @return mixed
+     */
+    static function xmlDeserialize(Reader $reader) {
+
+        // If there's no children, we don't do anything.
+        if ($reader->isEmptyElement) {
+            $reader->next();
+            return [];
+        }
+
+        $values = [];
+
+        $reader->read();
+        do {
+
+            if ($reader->nodeType === Reader::ELEMENT) {
+
+                $clark = $reader->getClark();
+                $values[$clark] = self::parseCurrentElement($reader)['value'];
+
+            } else {
+                $reader->read();
+            }
+
+        } while ($reader->nodeType !== Reader::END_ELEMENT);
+
+        $reader->read();
+
+        return $values;
+
+    }
+
+    /**
+     * This function behaves similar to Sabre\Xml\Reader::parseCurrentElement,
+     * but instead of creating deep xml array structures, it will turn any
+     * top-level element it doesn't recognize into either a string, or an
+     * XmlFragment class.
+     *
+     * This method returns arn array with 2 properties:
+     *   * name - A clark-notation XML element name.
+     *   * value - The parsed value.
+     *
+     * @param Reader $reader
+     * @return array
+     */
+    private static function parseCurrentElement(Reader $reader) {
+
+        $name = $reader->getClark();
+
+        if (array_key_exists($name, $reader->elementMap)) {
+            $deserializer = $reader->elementMap[$name];
+            if (is_subclass_of($deserializer, 'Sabre\\Xml\\XmlDeserializable')) {
+                $value = call_user_func([ $deserializer, 'xmlDeserialize' ], $reader);
+            } elseif (is_callable($deserializer)) {
+                $value = call_user_func($deserializer, $reader);
+            } else {
+                $type = gettype($deserializer);
+                if ($type === 'string') {
+                    $type .= ' (' . $deserializer . ')';
+                } elseif ($type === 'object') {
+                    $type .= ' (' . get_class($deserializer) . ')';
+                }
+                throw new \LogicException('Could not use this type as a deserializer: ' . $type);
+            }
+        } else {
+            $value = Complex::xmlDeserialize($reader);
+        }
+
+        return [
+            'name'  => $name,
+            'value' => $value,
+        ];
+
+    }
+
+}
diff --git a/vendor/sabre/dav/lib/DAV/Xml/Element/Response.php b/vendor/sabre/dav/lib/DAV/Xml/Element/Response.php
new file mode 100644
index 000000000..97a2bb59f
--- /dev/null
+++ b/vendor/sabre/dav/lib/DAV/Xml/Element/Response.php
@@ -0,0 +1,253 @@
+<?php
+
+namespace Sabre\DAV\Xml\Element;
+
+use Sabre\Xml\Element;
+use Sabre\Xml\Reader;
+use Sabre\Xml\Writer;
+
+/**
+ * WebDAV {DAV:}response parser
+ *
+ * This class parses the {DAV:}response element, as defined in:
+ *
+ * https://tools.ietf.org/html/rfc4918#section-14.24
+ *
+ * @copyright Copyright (C) fruux GmbH (https://fruux.com/)
+ * @author Evert Pot (http://www.rooftopsolutions.nl/)
+ * @license http://sabre.io/license/ Modified BSD License
+ */
+class Response implements Element {
+
+    /**
+     * Url for the response
+     *
+     * @var string
+     */
+    protected $href;
+
+    /**
+     * Propertylist, ordered by HTTP status code
+     *
+     * @var array
+     */
+    protected $responseProperties;
+
+    /**
+     * The HTTP status for an entire response.
+     *
+     * This is currently only used in WebDAV-Sync
+     *
+     * @var string
+     */
+    protected $httpStatus;
+
+    /**
+     * The href argument is a url relative to the root of the server. This
+     * class will calculate the full path.
+     *
+     * The responseProperties argument is a list of properties
+     * within an array with keys representing HTTP status codes
+     *
+     * Besides specific properties, the entire {DAV:}response element may also
+     * have a http status code.
+     * In most cases you don't need it.
+     *
+     * This is currently used by the Sync extension to indicate that a node is
+     * deleted.
+     *
+     * @param string $href
+     * @param array $responseProperties
+     * @param string $httpStatus
+     */
+    function __construct($href, array $responseProperties, $httpStatus = null) {
+
+        $this->href = $href;
+        $this->responseProperties = $responseProperties;
+        $this->httpStatus = $httpStatus;
+
+    }
+
+    /**
+     * Returns the url
+     *
+     * @return string
+     */
+    function getHref() {
+
+        return $this->href;
+
+    }
+
+    /**
+     * Returns the httpStatus value
+     *
+     * @return string
+     */
+    function getHttpStatus() {
+
+        return $this->httpStatus;
+
+    }
+
+    /**
+     * Returns the property list
+     *
+     * @return array
+     */
+    function getResponseProperties() {
+
+        return $this->responseProperties;
+
+    }
+
+
+    /**
+     * The serialize method is called during xml writing.
+     *
+     * It should use the $writer argument to encode this object into XML.
+     *
+     * Important note: it is not needed to create the parent element. The
+     * parent element is already created, and we only have to worry about
+     * attributes, child elements and text (if any).
+     *
+     * Important note 2: If you are writing any new elements, you are also
+     * responsible for closing them.
+     *
+     * @param Writer $writer
+     * @return void
+     */
+    function xmlSerialize(Writer $writer) {
+
+        if ($status = $this->getHTTPStatus()) {
+            $writer->writeElement('{DAV:}status', 'HTTP/1.1 ' . $status . ' ' . \Sabre\HTTP\Response::$statusCodes[$status]);
+        }
+        $writer->writeElement('{DAV:}href', $writer->contextUri . \Sabre\HTTP\encodePath($this->getHref()));
+
+        $empty = true;
+
+        foreach ($this->getResponseProperties() as $status => $properties) {
+
+            // Skipping empty lists
+            if (!$properties || (!ctype_digit($status) && !is_int($status))) {
+                continue;
+            }
+            $empty = false;
+            $writer->startElement('{DAV:}propstat');
+            $writer->writeElement('{DAV:}prop', $properties);
+            $writer->writeElement('{DAV:}status', 'HTTP/1.1 ' . $status . ' ' . \Sabre\HTTP\Response::$statusCodes[$status]);
+            $writer->endElement(); // {DAV:}propstat
+
+        }
+        if ($empty) {
+            /*
+             * The WebDAV spec _requires_ at least one DAV:propstat to appear for
+             * every DAV:response. In some circumstances however, there are no
+             * properties to encode.
+             *
+             * In those cases we MUST specify at least one DAV:propstat anyway, with
+             * no properties.
+             */
+            $writer->writeElement('{DAV:}propstat', [
+                '{DAV:}prop'   => [],
+                '{DAV:}status' => 'HTTP/1.1 418 ' . \Sabre\HTTP\Response::$statusCodes[418]
+            ]);
+
+        }
+
+    }
+
+    /**
+     * 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) {
+
+        $reader->pushContext();
+
+        $reader->elementMap['{DAV:}propstat'] = 'Sabre\\Xml\\Element\\KeyValue';
+
+        // We are overriding the parser for {DAV:}prop. This deserializer is
+        // almost identical to the one for Sabre\Xml\Element\KeyValue.
+        //
+        // The difference is that if there are any child-elements inside of
+        // {DAV:}prop, that have no value, normally any deserializers are
+        // called. But we don't want this, because a singular element without
+        // child-elements implies 'no value' in {DAV:}prop, so we want to skip
+        // deserializers and just set null for those.
+        $reader->elementMap['{DAV:}prop'] = function(Reader $reader) {
+
+            if ($reader->isEmptyElement) {
+                $reader->next();
+                return [];
+            }
+            $values = [];
+            $reader->read();
+            do {
+                if ($reader->nodeType === Reader::ELEMENT) {
+                    $clark = $reader->getClark();
+
+                    if ($reader->isEmptyElement) {
+                        $values[$clark] = null;
+                        $reader->next();
+                    } else {
+                        $values[$clark] = $reader->parseCurrentElement()['value'];
+                    }
+                } else {
+                    $reader->read();
+                }
+            } while ($reader->nodeType !== Reader::END_ELEMENT);
+            $reader->read();
+            return $values;
+
+        };
+        $elems = $reader->parseInnerTree();
+        $reader->popContext();
+
+        $href = null;
+        $propertyLists = [];
+        $statusCode = null;
+
+        foreach ($elems as $elem) {
+
+            switch ($elem['name']) {
+
+                case '{DAV:}href' :
+                    $href = $elem['value'];
+                    break;
+                case '{DAV:}propstat' :
+                    $status = $elem['value']['{DAV:}status'];
+                    list(, $status, ) = explode(' ', $status, 3);
+                    $properties = isset($elem['value']['{DAV:}prop']) ? $elem['value']['{DAV:}prop'] : [];
+                    if ($properties) $propertyLists[$status] = $properties;
+                    break;
+                case '{DAV:}status' :
+                    list(, $statusCode, ) = explode(' ', $elem['value'], 3);
+                    break;
+
+            }
+
+        }
+
+        return new self($href, $propertyLists, $statusCode);
+
+    }
+
+}
diff --git a/vendor/sabre/dav/lib/DAV/Xml/Property/Complex.php b/vendor/sabre/dav/lib/DAV/Xml/Property/Complex.php
new file mode 100644
index 000000000..1d9202082
--- /dev/null
+++ b/vendor/sabre/dav/lib/DAV/Xml/Property/Complex.php
@@ -0,0 +1,89 @@
+<?php
+
+namespace Sabre\DAV\Xml\Property;
+
+use Sabre\Xml\Element\XmlFragment;
+use Sabre\Xml\Reader;
+
+/**
+ * This class represents a 'complex' property that didn't have a default
+ * decoder.
+ *
+ * It's basically a container for an xml snippet.
+ *
+ * @copyright Copyright (C) fruux GmbH (https://fruux.com/)
+ * @author Evert Pot (http://evertpot.com/)
+ * @license http://sabre.io/license/ Modified BSD License
+ */
+class Complex extends XmlFragment {
+
+    /**
+     * 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) {
+
+        $xml = $reader->readInnerXml();
+
+        if ($reader->nodeType === Reader::ELEMENT && $reader->isEmptyElement) {
+            // Easy!
+            $reader->next();
+            return null;
+        }
+        // Now we have a copy of the inner xml, we need to traverse it to get
+        // all the strings. If there's no non-string data, we just return the
+        // string, otherwise we return an instance of this class.
+        $reader->read();
+
+        $nonText = false;
+        $text = '';
+
+        while (true) {
+
+            switch ($reader->nodeType) {
+                case Reader::ELEMENT :
+                    $nonText = true;
+                    $reader->next();
+                    continue 2;
+                case Reader::TEXT :
+                case Reader::CDATA :
+                    $text .= $reader->value;
+                    break;
+                case Reader::END_ELEMENT :
+                    break 2;
+            }
+            $reader->read();
+
+        }
+
+        // Make sure we advance the cursor one step further.
+        $reader->read();
+
+        if ($nonText) {
+            $new = new self($xml);
+            return $new;
+        } else {
+            return $text;
+        }
+
+    }
+
+
+}
diff --git a/vendor/sabre/dav/lib/DAV/Xml/Property/GetLastModified.php b/vendor/sabre/dav/lib/DAV/Xml/Property/GetLastModified.php
new file mode 100644
index 000000000..2db47269f
--- /dev/null
+++ b/vendor/sabre/dav/lib/DAV/Xml/Property/GetLastModified.php
@@ -0,0 +1,110 @@
+<?php
+
+namespace Sabre\DAV\Xml\Property;
+
+use Sabre\Xml\Element;
+use Sabre\Xml\Reader;
+use Sabre\Xml\Writer;
+use Sabre\HTTP;
+use DateTime;
+use DateTimeZone;
+
+/**
+ * This property represents the {DAV:}getlastmodified property.
+ *
+ * Defined in:
+ * http://tools.ietf.org/html/rfc4918#section-15.7
+ *
+ * @copyright Copyright (C) fruux GmbH (https://fruux.com/)
+ * @author Evert Pot (http://www.rooftopsolutions.nl/)
+ * @license http://sabre.io/license/ Modified BSD License
+ */
+class GetLastModified implements Element {
+
+    /**
+     * time
+     *
+     * @var DateTime
+     */
+    public $time;
+
+    /**
+     * Constructor
+     *
+     * @param int|DateTime $time
+     */
+    function __construct($time) {
+
+        if ($time instanceof DateTime) {
+            $this->time = clone $time;
+        } else {
+            $this->time = new DateTime('@' . $time);
+        }
+
+        // Setting timezone to UTC
+        $this->time->setTimezone(new DateTimeZone('UTC'));
+
+    }
+
+    /**
+     * getTime
+     *
+     * @return DateTime
+     */
+    function getTime() {
+
+        return $this->time;
+
+    }
+
+    /**
+     * The serialize method is called during xml writing.
+     *
+     * It should use the $writer argument to encode this object into XML.
+     *
+     * Important note: it is not needed to create the parent element. The
+     * parent element is already created, and we only have to worry about
+     * attributes, child elements and text (if any).
+     *
+     * Important note 2: If you are writing any new elements, you are also
+     * responsible for closing them.
+     *
+     * @param Writer $writer
+     * @return void
+     */
+    function xmlSerialize(Writer $writer) {
+
+        $writer->write(
+            HTTP\Util::toHTTPDate($this->time)
+        );
+
+    }
+
+    /**
+     * The deserialize method is called during xml parsing.
+     *
+     * This method is called statictly, this is because in theory this method
+     * may be used as a type of constructor, or factory method.
+     *
+     * Often you want to return an instance of the current class, but you are
+     * free to return other data as well.
+     *
+     * Important note 2: You are responsible for advancing the reader to the
+     * next element. Not doing anything will result in a never-ending loop.
+     *
+     * If you just want to skip parsing for this element altogether, you can
+     * just call $reader->next();
+     *
+     * $reader->parseInnerTree() will parse the entire sub-tree, and advance to
+     * the next element.
+     *
+     * @param Reader $reader
+     * @return mixed
+     */
+    static function xmlDeserialize(Reader $reader) {
+
+        return
+            new self(new DateTime($reader->parseInnerTree()));
+
+    }
+}
diff --git a/vendor/sabre/dav/lib/DAV/Xml/Property/Href.php b/vendor/sabre/dav/lib/DAV/Xml/Property/Href.php
new file mode 100644
index 000000000..538e98d0f
--- /dev/null
+++ b/vendor/sabre/dav/lib/DAV/Xml/Property/Href.php
@@ -0,0 +1,176 @@
+<?php
+
+namespace Sabre\DAV\Xml\Property;
+
+use Sabre\DAV\Browser\HtmlOutput;
+use Sabre\DAV\Browser\HtmlOutputHelper;
+use Sabre\Xml\Element;
+use Sabre\Xml\Reader;
+use Sabre\Xml\Writer;
+
+/**
+ * Href property
+ *
+ * This class represents any WebDAV property that contains a {DAV:}href
+ * element, and there are many.
+ *
+ * It can support either 1 or more hrefs. If while unserializing no valid
+ * {DAV:}href elements were found, this property will unserialize itself as
+ * null.
+ *
+ * @copyright Copyright (C) fruux GmbH (https://fruux.com/)
+ * @author Evert Pot (http://www.rooftopsolutions.nl/)
+ * @license http://sabre.io/license/ Modified BSD License
+ */
+class Href implements Element, HtmlOutput {
+
+    /**
+     * List of uris
+     *
+     * @var array
+     */
+    protected $hrefs;
+
+    /**
+     * Automatically prefix the url with the server base directory
+     *
+     * @var bool
+     */
+    protected $autoPrefix = true;
+
+    /**
+     * Constructor
+     *
+     * You must either pass a string for a single href, or an array of hrefs.
+     *
+     * If auto-prefix is set to false, the hrefs will be treated as absolute
+     * and not relative to the servers base uri.
+     *
+     * @param string|string[] $href
+     * @param bool $autoPrefix
+     */
+    function __construct($hrefs, $autoPrefix = true) {
+
+        if (is_string($hrefs)) {
+            $hrefs = [$hrefs];
+        }
+        $this->hrefs = $hrefs;
+        $this->autoPrefix = $autoPrefix;
+
+
+    }
+
+    /**
+     * Returns the first Href.
+     *
+     * @return string
+     */
+    function getHref() {
+
+        return $this->hrefs[0];
+
+    }
+
+    /**
+     * Returns the hrefs as an array
+     *
+     * @return array
+     */
+    function getHrefs() {
+
+        return $this->hrefs;
+
+    }
+
+    /**
+     * 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->getHrefs() as $href) {
+            if ($this->autoPrefix) {
+                $href = $writer->contextUri . \Sabre\HTTP\encodePath($href);
+            }
+            $writer->writeElement('{DAV:}href', $href);
+        }
+
+    }
+
+    /**
+     * Generate html representation for this value.
+     *
+     * The html output is 100% trusted, and no effort is being made to sanitize
+     * it. It's up to the implementor to sanitize user provided values.
+     *
+     * The output must be in UTF-8.
+     *
+     * The baseUri parameter is a url to the root of the application, and can
+     * be used to construct local links.
+     *
+     * @param HtmlOutputHelper $html
+     * @return string
+     */
+    function toHtml(HtmlOutputHelper $html) {
+
+        $links = [];
+        foreach ($this->getHrefs() as $href) {
+            $links[] = $html->link($href);
+        }
+        return implode('<br />', $links);
+
+    }
+
+    /**
+     * 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) {
+
+        $hrefs = [];
+        foreach ((array)$reader->parseInnerTree() as $elem) {
+            if ($elem['name'] !== '{DAV:}href')
+                continue;
+
+            $hrefs[] = $elem['value'];
+
+        }
+        if ($hrefs) {
+            return new self($hrefs, false);
+        }
+
+    }
+
+}
diff --git a/vendor/sabre/dav/lib/DAV/Xml/Property/LockDiscovery.php b/vendor/sabre/dav/lib/DAV/Xml/Property/LockDiscovery.php
new file mode 100644
index 000000000..f4b692219
--- /dev/null
+++ b/vendor/sabre/dav/lib/DAV/Xml/Property/LockDiscovery.php
@@ -0,0 +1,106 @@
+<?php
+
+namespace Sabre\DAV\Xml\Property;
+
+use Sabre\DAV;
+use Sabre\DAV\Locks\LockInfo;
+use Sabre\Xml\Element\XmlFragment;
+use Sabre\Xml\Writer;
+use Sabre\Xml\XmlSerializable;
+
+/**
+ * Represents {DAV:}lockdiscovery property.
+ *
+ * This property is defined here:
+ * http://tools.ietf.org/html/rfc4918#section-15.8
+ *
+ * This property contains all the open locks on a given resource
+ *
+ * @copyright Copyright (C) fruux GmbH (https://fruux.com/)
+ * @author Evert Pot (http://www.rooftopsolutions.nl/)
+ * @license http://sabre.io/license/ Modified BSD License
+ */
+class LockDiscovery implements XmlSerializable {
+
+    /**
+     * locks
+     *
+     * @var LockInfo[]
+     */
+    public $locks;
+
+    /**
+     * Hides the {DAV:}lockroot element from the response.
+     *
+     * It was reported that showing the lockroot in the response can break
+     * Office 2000 compatibility.
+     *
+     * @var bool
+     */
+    static $hideLockRoot = false;
+
+    /**
+     * __construct
+     *
+     * @param LockInfo[] $locks
+     */
+    function __construct($locks) {
+
+        $this->locks = $locks;
+
+    }
+
+    /**
+     * The serialize method is called during xml writing.
+     *
+     * It should use the $writer argument to encode this object into XML.
+     *
+     * Important note: it is not needed to create the parent element. The
+     * parent element is already created, and we only have to worry about
+     * attributes, child elements and text (if any).
+     *
+     * Important note 2: If you are writing any new elements, you are also
+     * responsible for closing them.
+     *
+     * @param Writer $writer
+     * @return void
+     */
+    function xmlSerialize(Writer $writer) {
+
+        foreach ($this->locks as $lock) {
+
+            $writer->startElement('{DAV:}activelock');
+
+            $writer->startElement('{DAV:}lockscope');
+            if ($lock->scope === LockInfo::SHARED) {
+                $writer->writeElement('{DAV:}shared');
+            } else {
+                $writer->writeElement('{DAV:}exclusive');
+            }
+
+            $writer->endElement(); // {DAV:}lockscope
+
+            $writer->startElement('{DAV:}locktype');
+            $writer->writeElement('{DAV:}write');
+            $writer->endElement(); // {DAV:}locktype
+
+            if (!self::$hideLockRoot) {
+                $writer->startElement('{DAV:}lockroot');
+                $writer->writeElement('{DAV:}href', $writer->contextUri . $lock->uri);
+                $writer->endElement(); // {DAV:}lockroot
+            }
+            $writer->writeElement('{DAV:}depth', ($lock->depth == DAV\Server::DEPTH_INFINITY ? 'infinity' : $lock->depth));
+            $writer->writeElement('{DAV:}timeout', 'Second-' . $lock->timeout);
+
+            $writer->startElement('{DAV:}locktoken');
+            $writer->writeElement('{DAV:}href', 'opaquelocktoken:' . $lock->token);
+            $writer->endElement(); // {DAV:}locktoken
+
+            $writer->writeElement('{DAV:}owner', new XmlFragment($lock->owner));
+            $writer->endElement(); // {DAV:}activelock
+
+        }
+
+    }
+
+}
diff --git a/vendor/sabre/dav/lib/DAV/Xml/Property/ResourceType.php b/vendor/sabre/dav/lib/DAV/Xml/Property/ResourceType.php
new file mode 100644
index 000000000..302888321
--- /dev/null
+++ b/vendor/sabre/dav/lib/DAV/Xml/Property/ResourceType.php
@@ -0,0 +1,128 @@
+<?php
+
+namespace Sabre\DAV\Xml\Property;
+
+use Sabre\DAV\Browser\HtmlOutput;
+use Sabre\DAV\Browser\HtmlOutputHelper;
+use Sabre\Xml\Element;
+use Sabre\Xml\Reader;
+
+/**
+ * {DAV:}resourcetype property
+ *
+ * This class represents the {DAV:}resourcetype property, as defined in:
+ *
+ * https://tools.ietf.org/html/rfc4918#section-15.9
+ *
+ * @copyright Copyright (C) fruux GmbH (https://fruux.com/)
+ * @author Evert Pot (http://evertpot.com/)
+ * @license http://sabre.io/license/ Modified BSD License
+ */
+class ResourceType extends Element\Elements implements HtmlOutput {
+
+    /**
+     * Constructor
+     *
+     * You can either pass null (for no resourcetype), a string (for a single
+     * resourcetype) or an array (for multiple).
+     *
+     * The resourcetype must be specified in clark-notation
+     *
+     * @param array|string|null $resourceType
+     */
+    function __construct($resourceTypes = null) {
+
+        parent::__construct((array)$resourceTypes);
+
+    }
+
+    /**
+     * Returns the values in clark-notation
+     *
+     * For example array('{DAV:}collection')
+     *
+     * @return array
+     */
+    function getValue() {
+
+        return $this->value;
+
+    }
+
+    /**
+     * Checks if the principal contains a certain value
+     *
+     * @param string $type
+     * @return bool
+     */
+    function is($type) {
+
+        return in_array($type, $this->value);
+
+    }
+
+    /**
+     * Adds a resourcetype value to this property
+     *
+     * @param string $type
+     * @return void
+     */
+    function add($type) {
+
+        $this->value[] = $type;
+        $this->value = array_unique($this->value);
+
+    }
+
+    /**
+     * The deserialize method is called during xml parsing.
+     *
+     * This method is called statictly, this is because in theory this method
+     * may be used as a type of constructor, or factory method.
+     *
+     * Often you want to return an instance of the current class, but you are
+     * free to return other data as well.
+     *
+     * Important note 2: You are responsible for advancing the reader to the
+     * next element. Not doing anything will result in a never-ending loop.
+     *
+     * If you just want to skip parsing for this element altogether, you can
+     * just call $reader->next();
+     *
+     * $reader->parseInnerTree() will parse the entire sub-tree, and advance to
+     * the next element.
+     *
+     * @param Reader $reader
+     * @return mixed
+     */
+    static function xmlDeserialize(Reader $reader) {
+
+        return
+            new self(parent::xmlDeserialize($reader));
+
+    }
+
+    /**
+     * Generate html representation for this value.
+     *
+     * The html output is 100% trusted, and no effort is being made to sanitize
+     * it. It's up to the implementor to sanitize user provided values.
+     *
+     * The output must be in UTF-8.
+     *
+     * The baseUri parameter is a url to the root of the application, and can
+     * be used to construct local links.
+     *
+     * @param HtmlOutputHelper $html
+     * @return string
+     */
+    function toHtml(HtmlOutputHelper $html) {
+
+        return implode(
+            ', ',
+            array_map([$html, 'xmlName'], $this->getValue())
+        );
+
+    }
+
+}
diff --git a/vendor/sabre/dav/lib/DAV/Xml/Property/SupportedLock.php b/vendor/sabre/dav/lib/DAV/Xml/Property/SupportedLock.php
new file mode 100644
index 000000000..f6d01aa37
--- /dev/null
+++ b/vendor/sabre/dav/lib/DAV/Xml/Property/SupportedLock.php
@@ -0,0 +1,54 @@
+<?php
+
+namespace Sabre\DAV\Xml\Property;
+
+use Sabre\Xml\Writer;
+use Sabre\Xml\XmlSerializable;
+
+/**
+ * This class represents the {DAV:}supportedlock property.
+ *
+ * This property is defined here:
+ * http://tools.ietf.org/html/rfc4918#section-15.10
+ *
+ * This property contains information about what kind of locks
+ * this server supports.
+ *
+ * @copyright Copyright (C) fruux GmbH (https://fruux.com/)
+ * @author Evert Pot (http://www.rooftopsolutions.nl/)
+ * @license http://sabre.io/license/ Modified BSD License
+ */
+class SupportedLock implements XmlSerializable {
+
+    /**
+     * The xmlSerialize metod is called during xml writing.
+     *
+     * Use the $writer argument to write its own xml serialization.
+     *
+     * An important note: do _not_ create a parent element. Any element
+     * implementing XmlSerializble should only ever write what's considered
+     * its 'inner xml'.
+     *
+     * The parent of the current element is responsible for writing a
+     * containing element.
+     *
+     * This allows serializers to be re-used for different element names.
+     *
+     * If you are opening new elements, you must also close them again.
+     *
+     * @param Writer $writer
+     * @return void
+     */
+    function xmlSerialize(Writer $writer) {
+
+        $writer->writeElement('{DAV:}lockentry', [
+            '{DAV:}lockscope' => ['{DAV:}exclusive' => null],
+            '{DAV:}locktype'  => ['{DAV:}write'     => null],
+        ]);
+        $writer->writeElement('{DAV:}lockentry', [
+            '{DAV:}lockscope' => ['{DAV:}shared' => null],
+            '{DAV:}locktype'  => ['{DAV:}write'  => null],
+        ]);
+
+    }
+}
diff --git a/vendor/sabre/dav/lib/DAV/Xml/Property/SupportedMethodSet.php b/vendor/sabre/dav/lib/DAV/Xml/Property/SupportedMethodSet.php
new file mode 100644
index 000000000..56b418db6
--- /dev/null
+++ b/vendor/sabre/dav/lib/DAV/Xml/Property/SupportedMethodSet.php
@@ -0,0 +1,126 @@
+<?php
+
+namespace Sabre\DAV\Xml\Property;
+
+use Sabre\DAV\Browser\HtmlOutput;
+use Sabre\DAV\Browser\HtmlOutputHelper;
+use Sabre\Xml\Writer;
+use Sabre\Xml\XmlSerializable;
+
+/**
+ * supported-method-set property.
+ *
+ * This property is defined in RFC3253, but since it's
+ * so common in other webdav-related specs, it is part of the core server.
+ *
+ * This property is defined here:
+ * http://tools.ietf.org/html/rfc3253#section-3.1.3
+ *
+ * @copyright Copyright (C) fruux GmbH (https://fruux.com/)
+ * @author Evert Pot (http://evertpot.com/)
+ * @license http://sabre.io/license/ Modified BSD License
+ */
+class SupportedMethodSet implements XmlSerializable, HtmlOutput {
+
+    /**
+     * List of methods
+     *
+     * @var string[]
+     */
+    protected $methods = [];
+
+    /**
+     * Creates the property
+     *
+     * Any reports passed in the constructor
+     * should be valid report-types in clark-notation.
+     *
+     * Either a string or an array of strings must be passed.
+     *
+     * @param string|string[] $methods
+     */
+    function __construct($methods = null) {
+
+        $this->methods = (array)$methods;
+
+    }
+
+    /**
+     * Returns the list of supported http methods.
+     *
+     * @return string[]
+     */
+    function getValue() {
+
+        return $this->methods;
+
+    }
+
+    /**
+     * Returns true or false if the property contains a specific method.
+     *
+     * @param string $methodName
+     * @return bool
+     */
+    function has($methodName) {
+
+        return in_array(
+            $methodName,
+            $this->methods
+        );
+
+    }
+
+    /**
+     * 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->getValue() as $val) {
+            $writer->startElement('{DAV:}supported-method');
+            $writer->writeAttribute('name', $val);
+            $writer->endElement();
+        }
+
+    }
+
+    /**
+     * Generate html representation for this value.
+     *
+     * The html output is 100% trusted, and no effort is being made to sanitize
+     * it. It's up to the implementor to sanitize user provided values.
+     *
+     * The output must be in UTF-8.
+     *
+     * The baseUri parameter is a url to the root of the application, and can
+     * be used to construct local links.
+     *
+     * @param HtmlOutputHelper $html
+     * @return string
+     */
+    function toHtml(HtmlOutputHelper $html) {
+
+        return implode(
+            ', ',
+            array_map([$html, 'h'], $this->getValue())
+        );
+
+    }
+
+}
diff --git a/vendor/sabre/dav/lib/DAV/Xml/Property/SupportedReportSet.php b/vendor/sabre/dav/lib/DAV/Xml/Property/SupportedReportSet.php
new file mode 100644
index 000000000..ebf27300d
--- /dev/null
+++ b/vendor/sabre/dav/lib/DAV/Xml/Property/SupportedReportSet.php
@@ -0,0 +1,154 @@
+<?php
+
+namespace Sabre\DAV\Xml\Property;
+
+use Sabre\DAV;
+use Sabre\DAV\Browser\HtmlOutput;
+use Sabre\DAV\Browser\HtmlOutputHelper;
+use Sabre\Xml\Writer;
+use Sabre\Xml\XmlSerializable;
+
+/**
+ * supported-report-set property.
+ *
+ * This property is defined in RFC3253, but since it's
+ * so common in other webdav-related specs, it is part of the core server.
+ *
+ * This property is defined here:
+ * http://tools.ietf.org/html/rfc3253#section-3.1.5
+ *
+ * @copyright Copyright (C) fruux GmbH (https://fruux.com/)
+ * @author Evert Pot (http://www.rooftopsolutions.nl/)
+ * @license http://sabre.io/license/ Modified BSD License
+ */
+class SupportedReportSet implements XmlSerializable, HtmlOutput {
+
+    /**
+     * List of reports
+     *
+     * @var array
+     */
+    protected $reports = [];
+
+    /**
+     * Creates the property
+     *
+     * Any reports passed in the constructor
+     * should be valid report-types in clark-notation.
+     *
+     * Either a string or an array of strings must be passed.
+     *
+     * @param string|string[] $reports
+     */
+    function __construct($reports = null) {
+
+        if (!is_null($reports))
+            $this->addReport($reports);
+
+    }
+
+    /**
+     * Adds a report to this property
+     *
+     * The report must be a string in clark-notation.
+     * Multiple reports can be specified as an array.
+     *
+     * @param mixed $report
+     * @return void
+     */
+    function addReport($report) {
+
+        $report = (array)$report;
+
+        foreach ($report as $r) {
+
+            if (!preg_match('/^{([^}]*)}(.*)$/', $r))
+                throw new DAV\Exception('Reportname must be in clark-notation');
+
+            $this->reports[] = $r;
+
+        }
+
+    }
+
+    /**
+     * Returns the list of supported reports
+     *
+     * @return string[]
+     */
+    function getValue() {
+
+        return $this->reports;
+
+    }
+
+    /**
+     * Returns true or false if the property contains a specific report.
+     *
+     * @param string $reportName
+     * @return bool
+     */
+    function has($reportName) {
+
+        return in_array(
+            $reportName,
+            $this->reports
+        );
+
+    }
+
+    /**
+     * 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->getValue() as $val) {
+            $writer->startElement('{DAV:}supported-report');
+            $writer->startElement('{DAV:}report');
+            $writer->writeElement($val);
+            $writer->endElement();
+            $writer->endElement();
+        }
+
+    }
+
+    /**
+     * Generate html representation for this value.
+     *
+     * The html output is 100% trusted, and no effort is being made to sanitize
+     * it. It's up to the implementor to sanitize user provided values.
+     *
+     * The output must be in UTF-8.
+     *
+     * The baseUri parameter is a url to the root of the application, and can
+     * be used to construct local links.
+     *
+     * @param HtmlOutputHelper $html
+     * @return string
+     */
+    function toHtml(HtmlOutputHelper $html) {
+
+        return implode(
+            ', ',
+            array_map([$html, 'xmlName'], $this->getValue())
+        );
+
+    }
+
+}
diff --git a/vendor/sabre/dav/lib/DAV/Xml/Request/Lock.php b/vendor/sabre/dav/lib/DAV/Xml/Request/Lock.php
new file mode 100644
index 000000000..76df98d13
--- /dev/null
+++ b/vendor/sabre/dav/lib/DAV/Xml/Request/Lock.php
@@ -0,0 +1,81 @@
+<?php
+
+namespace Sabre\DAV\Xml\Request;
+
+use Sabre\DAV\Locks\LockInfo;
+use Sabre\Xml\Element\KeyValue;
+use Sabre\Xml\Reader;
+use Sabre\Xml\XmlDeserializable;
+
+/**
+ * WebDAV LOCK request parser.
+ *
+ * This class parses the {DAV:}lockinfo request, as defined in:
+ *
+ * http://tools.ietf.org/html/rfc4918#section-9.10
+ *
+ * @copyright Copyright (C) fruux GmbH (https://fruux.com/)
+ * @author Evert Pot (http://evertpot.com/)
+ * @license http://sabre.io/license/ Modified BSD License
+ */
+class Lock implements XmlDeserializable {
+
+    /**
+     * Owner of the lock
+     *
+     * @var string
+     */
+    public $owner;
+
+    /**
+     * Scope of the lock.
+     *
+     * Either LockInfo::SHARED or LockInfo::EXCLUSIVE
+     * @var int
+     */
+    public $scope;
+
+    /**
+     * 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) {
+
+        $reader->pushContext();
+        $reader->elementMap['{DAV:}owner'] = 'Sabre\\Xml\\Element\\XmlFragment';
+
+        $values = KeyValue::xmlDeserialize($reader);
+
+        $reader->popContext();
+
+        $new = new self();
+        $new->owner = !empty($values['{DAV:}owner']) ? $values['{DAV:}owner']->getXml() : null;
+        $new->scope = LockInfo::SHARED;
+
+        if (isset($values['{DAV:}lockscope'])) {
+            foreach ($values['{DAV:}lockscope'] as $elem) {
+                if ($elem['name'] === '{DAV:}exclusive') $new->scope = LockInfo::EXCLUSIVE;
+            }
+        }
+        return $new;
+
+    }
+
+}
diff --git a/vendor/sabre/dav/lib/DAV/Xml/Request/MkCol.php b/vendor/sabre/dav/lib/DAV/Xml/Request/MkCol.php
new file mode 100644
index 000000000..5db239061
--- /dev/null
+++ b/vendor/sabre/dav/lib/DAV/Xml/Request/MkCol.php
@@ -0,0 +1,82 @@
+<?php
+
+namespace Sabre\DAV\Xml\Request;
+
+use Sabre\Xml\Reader;
+use Sabre\Xml\XmlDeserializable;
+
+/**
+ * WebDAV Extended MKCOL request parser.
+ *
+ * This class parses the {DAV:}mkol request, as defined in:
+ *
+ * https://tools.ietf.org/html/rfc5689#section-5.1
+ *
+ * @copyright Copyright (C) fruux GmbH (https://fruux.com/)
+ * @author Evert Pot (http://evertpot.com/)
+ * @license http://sabre.io/license/ Modified BSD License
+ */
+class MkCol implements XmlDeserializable {
+
+    /**
+     * The list of properties that will be set.
+     *
+     * @var array
+     */
+    protected $properties = [];
+
+    /**
+     * Returns a key=>value array with properties that are supposed to get set
+     * during creation of the new collection.
+     *
+     * @return array
+     */
+    function getProperties() {
+
+        return $this->properties;
+
+    }
+
+    /**
+     * The deserialize method is called during xml parsing.
+     *
+     * This method is called statictly, this is because in theory this method
+     * may be used as a type of constructor, or factory method.
+     *
+     * Often you want to return an instance of the current class, but you are
+     * free to return other data as well.
+     *
+     * You are responsible for advancing the reader to the next element. Not
+     * doing anything will result in a never-ending loop.
+     *
+     * If you just want to skip parsing for this element altogether, you can
+     * just call $reader->next();
+     *
+     * $reader->parseInnerTree() will parse the entire sub-tree, and advance to
+     * the next element.
+     *
+     * @param Reader $reader
+     * @return mixed
+     */
+    static function xmlDeserialize(Reader $reader) {
+
+        $self = new self();
+
+        $elementMap = $reader->elementMap;
+        $elementMap['{DAV:}prop']   = 'Sabre\DAV\Xml\Element\Prop';
+        $elementMap['{DAV:}set']    = 'Sabre\Xml\Element\KeyValue';
+        $elementMap['{DAV:}remove'] = 'Sabre\Xml\Element\KeyValue';
+
+        $elems = $reader->parseInnerTree($elementMap);
+
+        foreach ($elems as $elem) {
+            if ($elem['name'] === '{DAV:}set') {
+                $self->properties = array_merge($self->properties, $elem['value']['{DAV:}prop']);
+            }
+        }
+
+        return $self;
+
+    }
+
+}
diff --git a/vendor/sabre/dav/lib/DAV/Xml/Request/PropFind.php b/vendor/sabre/dav/lib/DAV/Xml/Request/PropFind.php
new file mode 100644
index 000000000..ad3ad7c43
--- /dev/null
+++ b/vendor/sabre/dav/lib/DAV/Xml/Request/PropFind.php
@@ -0,0 +1,83 @@
+<?php
+
+namespace Sabre\DAV\Xml\Request;
+
+use Sabre\Xml\Element\KeyValue;
+use Sabre\Xml\Reader;
+use Sabre\Xml\XmlDeserializable;
+
+/**
+ * WebDAV PROPFIND request parser.
+ *
+ * This class parses the {DAV:}propfind request, as defined in:
+ *
+ * https://tools.ietf.org/html/rfc4918#section-14.20
+ *
+ * @copyright Copyright (C) fruux GmbH (https://fruux.com/)
+ * @author Evert Pot (http://www.rooftopsolutions.nl/)
+ * @license http://sabre.io/license/ Modified BSD License
+ */
+class PropFind implements XmlDeserializable {
+
+    /**
+     * If this is set to true, this was an 'allprop' request.
+     *
+     * @var bool
+     */
+    public $allProp = false;
+
+    /**
+     * The property list
+     *
+     * @var null|array
+     */
+    public $properties;
+
+    /**
+     * The deserialize method is called during xml parsing.
+     *
+     * This method is called statictly, this is because in theory this method
+     * may be used as a type of constructor, or factory method.
+     *
+     * Often you want to return an instance of the current class, but you are
+     * free to return other data as well.
+     *
+     * You are responsible for advancing the reader to the next element. Not
+     * doing anything will result in a never-ending loop.
+     *
+     * If you just want to skip parsing for this element altogether, you can
+     * just call $reader->next();
+     *
+     * $reader->parseInnerTree() will parse the entire sub-tree, and advance to
+     * the next element.
+     *
+     * @param Reader $reader
+     * @return mixed
+     */
+    static function xmlDeserialize(Reader $reader) {
+
+        $self = new self();
+
+        $reader->pushContext();
+        $reader->elementMap['{DAV:}prop'] = 'Sabre\Xml\Element\Elements';
+
+        foreach (KeyValue::xmlDeserialize($reader) as $k => $v) {
+
+            switch ($k) {
+                case '{DAV:}prop' :
+                    $self->properties = $v;
+                    break;
+                case '{DAV:}allprop' :
+                    $self->allProp = true;
+
+            }
+
+        }
+
+        $reader->popContext();
+
+        return $self;
+
+    }
+
+}
diff --git a/vendor/sabre/dav/lib/DAV/Xml/Request/PropPatch.php b/vendor/sabre/dav/lib/DAV/Xml/Request/PropPatch.php
new file mode 100644
index 000000000..07a05f887
--- /dev/null
+++ b/vendor/sabre/dav/lib/DAV/Xml/Request/PropPatch.php
@@ -0,0 +1,118 @@
+<?php
+
+namespace Sabre\DAV\Xml\Request;
+
+use Sabre\Xml\Element;
+use Sabre\Xml\Reader;
+use Sabre\Xml\Writer;
+
+/**
+ * WebDAV PROPPATCH request parser.
+ *
+ * This class parses the {DAV:}propertyupdate request, as defined in:
+ *
+ * https://tools.ietf.org/html/rfc4918#section-14.20
+ *
+ * @copyright Copyright (C) fruux GmbH (https://fruux.com/)
+ * @author Evert Pot (http://www.rooftopsolutions.nl/)
+ * @license http://sabre.io/license/ Modified BSD License
+ */
+class PropPatch implements Element {
+
+    /**
+     * The list of properties that will be updated and removed.
+     *
+     * If a property will be removed, it's value will be set to null.
+     *
+     * @var array
+     */
+    public $properties = [];
+
+    /**
+     * 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->properties as $propertyName => $propertyValue) {
+
+            if (is_null($propertyValue)) {
+                $writer->startElement("{DAV:}remove");
+                $writer->write(['{DAV:}prop' => [$propertyName => $propertyValue]]);
+                $writer->endElement();
+            } else {
+                $writer->startElement("{DAV:}set");
+                $writer->write(['{DAV:}prop' => [$propertyName => $propertyValue]]);
+                $writer->endElement();
+            }
+
+        }
+
+    }
+
+    /**
+     * The deserialize method is called during xml parsing.
+     *
+     * This method is called statictly, this is because in theory this method
+     * may be used as a type of constructor, or factory method.
+     *
+     * Often you want to return an instance of the current class, but you are
+     * free to return other data as well.
+     *
+     * You are responsible for advancing the reader to the next element. Not
+     * doing anything will result in a never-ending loop.
+     *
+     * If you just want to skip parsing for this element altogether, you can
+     * just call $reader->next();
+     *
+     * $reader->parseInnerTree() will parse the entire sub-tree, and advance to
+     * the next element.
+     *
+     * @param Reader $reader
+     * @return mixed
+     */
+    static function xmlDeserialize(Reader $reader) {
+
+        $self = new self();
+
+        $elementMap = $reader->elementMap;
+        $elementMap['{DAV:}prop']   = 'Sabre\DAV\Xml\Element\Prop';
+        $elementMap['{DAV:}set']    = 'Sabre\Xml\Element\KeyValue';
+        $elementMap['{DAV:}remove'] = 'Sabre\Xml\Element\KeyValue';
+
+        $elems = $reader->parseInnerTree($elementMap);
+
+        foreach ($elems as $elem) {
+            if ($elem['name'] === '{DAV:}set') {
+                $self->properties = array_merge($self->properties, $elem['value']['{DAV:}prop']);
+            }
+            if ($elem['name'] === '{DAV:}remove') {
+
+                // Ensuring there are no values.
+                foreach ($elem['value']['{DAV:}prop'] as $remove => $value) {
+                    $self->properties[$remove] = null;
+                }
+
+            }
+        }
+
+        return $self;
+
+    }
+
+}
diff --git a/vendor/sabre/dav/lib/DAV/Xml/Request/SyncCollectionReport.php b/vendor/sabre/dav/lib/DAV/Xml/Request/SyncCollectionReport.php
new file mode 100644
index 000000000..3092ada47
--- /dev/null
+++ b/vendor/sabre/dav/lib/DAV/Xml/Request/SyncCollectionReport.php
@@ -0,0 +1,122 @@
+<?php
+
+namespace Sabre\DAV\Xml\Request;
+
+use Sabre\Xml\Reader;
+use Sabre\Xml\XmlDeserializable;
+use Sabre\Xml\Element\KeyValue;
+use Sabre\DAV\Exception\BadRequest;
+
+/**
+ * SyncCollection request parser.
+ *
+ * This class parses the {DAV:}sync-collection reprot, as defined in:
+ *
+ * http://tools.ietf.org/html/rfc6578#section-3.2
+ *
+ * @copyright Copyright (C) fruux GmbH (https://fruux.com/)
+ * @author Evert Pot (http://www.rooftopsolutions.nl/)
+ * @license http://sabre.io/license/ Modified BSD License
+ */
+class SyncCollectionReport implements XmlDeserializable {
+
+    /**
+     * The sync-token the client supplied for the report.
+     *
+     * @var string|null
+     */
+    public $syncToken;
+
+    /**
+     * The 'depth' of the sync the client is interested in.
+     *
+     * @var int
+     */
+    public $syncLevel;
+
+    /**
+     * Maximum amount of items returned.
+     *
+     * @var int|null
+     */
+    public $limit;
+
+    /**
+     * The list of properties that are being requested for every change.
+     *
+     * @var null|array
+     */
+    public $properties;
+
+    /**
+     * The deserialize method is called during xml parsing.
+     *
+     * This method is called statictly, this is because in theory this method
+     * may be used as a type of constructor, or factory method.
+     *
+     * Often you want to return an instance of the current class, but you are
+     * free to return other data as well.
+     *
+     * You are responsible for advancing the reader to the next element. Not
+     * doing anything will result in a never-ending loop.
+     *
+     * If you just want to skip parsing for this element altogether, you can
+     * just call $reader->next();
+     *
+     * $reader->parseInnerTree() will parse the entire sub-tree, and advance to
+     * the next element.
+     *
+     * @param Reader $reader
+     * @return mixed
+     */
+    static function xmlDeserialize(Reader $reader) {
+
+        $self = new self();
+
+        $reader->pushContext();
+
+        $reader->elementMap['{DAV:}prop']   = 'Sabre\Xml\Element\Elements';
+        $elems = KeyValue::xmlDeserialize($reader);
+
+        $reader->popContext();
+
+        $required = [
+            '{DAV:}sync-token',
+            '{DAV:}prop',
+            ];
+
+        foreach ($required as $elem) {
+            if (!array_key_exists($elem, $elems)) {
+                throw new BadRequest('The ' . $elem . ' element in the {DAV:}sync-collection report is required');
+            }
+        }
+
+
+        $self->properties = $elems['{DAV:}prop'];
+        $self->syncToken = $elems['{DAV:}sync-token'];
+
+        if (isset($elems['{DAV:}limit'])) {
+            $nresults = null;
+            foreach ($elems['{DAV:}limit'] as $child) {
+                if ($child['name'] === '{DAV:}nresults') {
+                    $nresults = (int)$child['value'];
+                }
+            }
+            $self->limit = $nresults;
+        }
+
+        if (isset($elems['{DAV:}sync-level'])) {
+
+            $value = $elems['{DAV:}sync-level'];
+            if ($value === 'infinity') {
+                $value = \Sabre\DAV\Server::DEPTH_INFINITY;
+            }
+            $self->syncLevel = $value;
+
+        }
+
+        return $self;
+
+    }
+
+}
diff --git a/vendor/sabre/dav/lib/DAV/Xml/Response/MultiStatus.php b/vendor/sabre/dav/lib/DAV/Xml/Response/MultiStatus.php
new file mode 100644
index 000000000..16a3d4a68
--- /dev/null
+++ b/vendor/sabre/dav/lib/DAV/Xml/Response/MultiStatus.php
@@ -0,0 +1,142 @@
+<?php
+
+namespace Sabre\DAV\Xml\Response;
+
+use Sabre\Xml\Element;
+use Sabre\Xml\Reader;
+use Sabre\Xml\Writer;
+
+/**
+ * WebDAV MultiStatus parser
+ *
+ * This class parses the {DAV:}multistatus response, as defined in:
+ * https://tools.ietf.org/html/rfc4918#section-14.16
+ *
+ * And it also adds the {DAV:}synctoken change from:
+ * http://tools.ietf.org/html/rfc6578#section-6.4
+ *
+ * @copyright Copyright (C) fruux GmbH (https://fruux.com/)
+ * @author Evert Pot (http://evertpot.com/)
+ * @license http://sabre.io/license/ Modified BSD License
+ */
+class MultiStatus implements Element {
+
+    /**
+     * The responses
+     *
+     * @var \Sabre\DAV\Xml\Element\Response[]
+     */
+    protected $responses;
+
+    /**
+     * A sync token (from RFC6578).
+     *
+     * @var string
+     */
+    protected $syncToken;
+
+    /**
+     * Constructor
+     *
+     * @param \Sabre\DAV\Xml\Element\Response[] $responses
+     * @param string $syncToken
+     */
+    function __construct(array $responses, $syncToken = null) {
+
+        $this->responses = $responses;
+        $this->syncToken = $syncToken;
+
+    }
+
+    /**
+     * Returns the response list.
+     *
+     * @return \Sabre\DAV\Xml\Element\Response[]
+     */
+    function getResponses() {
+
+        return $this->responses;
+
+    }
+
+    /**
+     * Returns the sync-token, if available.
+     *
+     * @return string|null
+     */
+    function getSyncToken() {
+
+        return $this->syncToken;
+
+    }
+
+    /**
+     * The serialize method is called during xml writing.
+     *
+     * It should use the $writer argument to encode this object into XML.
+     *
+     * Important note: it is not needed to create the parent element. The
+     * parent element is already created, and we only have to worry about
+     * attributes, child elements and text (if any).
+     *
+     * Important note 2: If you are writing any new elements, you are also
+     * responsible for closing them.
+     *
+     * @param Writer $writer
+     * @return void
+     */
+    function xmlSerialize(Writer $writer) {
+
+        foreach ($this->getResponses() as $response) {
+            $writer->writeElement('{DAV:}response', $response);
+        }
+        if ($syncToken = $this->getSyncToken()) {
+            $writer->writeElement('{DAV:}sync-token', $syncToken);
+        }
+
+    }
+
+    /**
+     * 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) {
+
+        $elementMap = $reader->elementMap;
+        $elementMap['{DAV:}prop'] = 'Sabre\\DAV\\Xml\\Element\\Prop';
+        $elements = $reader->parseInnerTree($elementMap);
+
+        $responses = [];
+        $syncToken = null;
+
+        if ($elements) foreach ($elements as $elem) {
+            if ($elem['name'] === '{DAV:}response') {
+                $responses[] = $elem['value'];
+            }
+            if ($elem['name'] === '{DAV:}sync-token') {
+                $syncToken = $elem['value'];
+            }
+        }
+
+        return new self($responses, $syncToken);
+
+    }
+
+}
diff --git a/vendor/sabre/dav/lib/DAV/Xml/Service.php b/vendor/sabre/dav/lib/DAV/Xml/Service.php
new file mode 100644
index 000000000..f41ed984a
--- /dev/null
+++ b/vendor/sabre/dav/lib/DAV/Xml/Service.php
@@ -0,0 +1,47 @@
+<?php
+
+namespace Sabre\DAV\Xml;
+
+/**
+ * XML service for WebDAV
+ *
+ * @copyright Copyright (C) fruux GmbH (https://fruux.com/)
+ * @author Evert Pot (http://evertpot.com/)
+ * @license http://sabre.io/license/ Modified BSD License
+ */
+class Service extends \Sabre\Xml\Service {
+
+    /**
+     * This is a list of XML elements that we automatically map to PHP classes.
+     *
+     * For instance, this list may contain an entry `{DAV:}propfind` that would
+     * be mapped to Sabre\DAV\Xml\Request\PropFind
+     */
+    public $elementMap = [
+        '{DAV:}multistatus' => 'Sabre\\DAV\\Xml\\Response\\MultiStatus',
+        '{DAV:}response'    => 'Sabre\\DAV\\Xml\\Element\\Response',
+
+        // Requests
+        '{DAV:}propfind'       => 'Sabre\\DAV\\Xml\\Request\\PropFind',
+        '{DAV:}propertyupdate' => 'Sabre\\DAV\\Xml\\Request\\PropPatch',
+        '{DAV:}mkcol'          => 'Sabre\\DAV\\Xml\\Request\\MkCol',
+
+        // Properties
+        '{DAV:}resourcetype' => 'Sabre\\DAV\\Xml\\Property\\ResourceType',
+
+    ];
+
+    /**
+     * This is a default list of namespaces.
+     *
+     * If you are defining your own custom namespace, add it here to reduce
+     * bandwidth and improve legibility of xml bodies.
+     *
+     * @var array
+     */
+    public $namespaceMap = [
+        'DAV:'                   => 'd',
+        'http://sabredav.org/ns' => 's',
+    ];
+
+}