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

10 files changed, 2160 insertions, 0 deletions

diff --git a/vendor/sabre/vobject/lib/Component/Available.php b/vendor/sabre/vobject/lib/Component/Available.php
new file mode 100644
index 000000000..b3aaf08af
--- /dev/null
+++ b/vendor/sabre/vobject/lib/Component/Available.php
@@ -0,0 +1,126 @@
+<?php
+
+namespace Sabre\VObject\Component;
+
+use Sabre\VObject;
+
+/**
+ * The Available sub-component.
+ *
+ * This component adds functionality to a component, specific for AVAILABLE
+ * components.
+ *
+ * @copyright Copyright (C) fruux GmbH (https://fruux.com/)
+ * @author Ivan Enderlin
+ * @license http://sabre.io/license/ Modified BSD License
+ */
+class Available extends VObject\Component {
+
+    /**
+     * Returns the 'effective start' and 'effective end' of this VAVAILABILITY
+     * component.
+     *
+     * We use the DTSTART and DTEND or DURATION to determine this.
+     *
+     * The returned value is an array containing DateTimeImmutable instances.
+     * If either the start or end is 'unbounded' its value will be null
+     * instead.
+     *
+     * @return array
+     */
+    function getEffectiveStartEnd() {
+
+        $effectiveStart = $this->DTSTART->getDateTime();
+        if (isset($this->DTEND)) {
+            $effectiveEnd = $this->DTEND->getDateTime();
+        } else {
+            $effectiveEnd = $effectiveStart->add(VObject\DateTimeParser::parseDuration($this->DURATION));
+        }
+
+        return [$effectiveStart, $effectiveEnd];
+
+    }
+
+    /**
+     * A simple list of validation rules.
+     *
+     * This is simply a list of properties, and how many times they either
+     * must or must not appear.
+     *
+     * Possible values per property:
+     *   * 0 - Must not appear.
+     *   * 1 - Must appear exactly once.
+     *   * + - Must appear at least once.
+     *   * * - Can appear any number of times.
+     *   * ? - May appear, but not more than once.
+     *
+     * @var array
+     */
+    function getValidationRules() {
+
+        return [
+            'UID'     => 1,
+            'DTSTART' => 1,
+            'DTSTAMP' => 1,
+
+            'DTEND'    => '?',
+            'DURATION' => '?',
+
+            'CREATED'       => '?',
+            'DESCRIPTION'   => '?',
+            'LAST-MODIFIED' => '?',
+            'RECURRENCE-ID' => '?',
+            'RRULE'         => '?',
+            'SUMMARY'       => '?',
+
+            'CATEGORIES' => '*',
+            'COMMENT'    => '*',
+            'CONTACT'    => '*',
+            'EXDATE'     => '*',
+            'RDATE'      => '*',
+
+            'AVAILABLE' => '*',
+        ];
+
+    }
+
+    /**
+     * Validates the node for correctness.
+     *
+     * The following options are supported:
+     *   Node::REPAIR - May attempt to automatically repair the problem.
+     *   Node::PROFILE_CARDDAV - Validate the vCard for CardDAV purposes.
+     *   Node::PROFILE_CALDAV - Validate the iCalendar for CalDAV purposes.
+     *
+     * This method returns an array with detected problems.
+     * Every element has the following properties:
+     *
+     *  * level - problem level.
+     *  * message - A human-readable string describing the issue.
+     *  * node - A reference to the problematic node.
+     *
+     * The level means:
+     *   1 - The issue was repaired (only happens if REPAIR was turned on).
+     *   2 - A warning.
+     *   3 - An error.
+     *
+     * @param int $options
+     *
+     * @return array
+     */
+    function validate($options = 0) {
+
+        $result = parent::validate($options);
+
+        if (isset($this->DTEND) && isset($this->DURATION)) {
+            $result[] = [
+                'level'   => 3,
+                'message' => 'DTEND and DURATION cannot both be present',
+                'node'    => $this
+            ];
+        }
+
+        return $result;
+
+    }
+}
diff --git a/vendor/sabre/vobject/lib/Component/VAlarm.php b/vendor/sabre/vobject/lib/Component/VAlarm.php
new file mode 100644
index 000000000..8cbd572e6
--- /dev/null
+++ b/vendor/sabre/vobject/lib/Component/VAlarm.php
@@ -0,0 +1,142 @@
+<?php
+
+namespace Sabre\VObject\Component;
+
+use Sabre\VObject;
+use Sabre\VObject\InvalidDataException;
+use DateTimeInterface;
+use DateTimeImmutable;
+
+/**
+ * VAlarm component.
+ *
+ * This component contains some additional functionality specific for VALARMs.
+ *
+ * @copyright Copyright (C) fruux GmbH (https://fruux.com/)
+ * @author Evert Pot (http://evertpot.com/)
+ * @license http://sabre.io/license/ Modified BSD License
+ */
+class VAlarm extends VObject\Component {
+
+    /**
+     * Returns a DateTime object when this alarm is going to trigger.
+     *
+     * This ignores repeated alarm, only the first trigger is returned.
+     *
+     * @return DateTimeImmutable
+     */
+    function getEffectiveTriggerTime() {
+
+        $trigger = $this->TRIGGER;
+        if (!isset($trigger['VALUE']) || strtoupper($trigger['VALUE']) === 'DURATION') {
+            $triggerDuration = VObject\DateTimeParser::parseDuration($this->TRIGGER);
+            $related = (isset($trigger['RELATED']) && strtoupper($trigger['RELATED']) == 'END') ? 'END' : 'START';
+
+            $parentComponent = $this->parent;
+            if ($related === 'START') {
+
+                if ($parentComponent->name === 'VTODO') {
+                    $propName = 'DUE';
+                } else {
+                    $propName = 'DTSTART';
+                }
+
+                $effectiveTrigger = $parentComponent->$propName->getDateTime();
+                $effectiveTrigger = $effectiveTrigger->add($triggerDuration);
+            } else {
+                if ($parentComponent->name === 'VTODO') {
+                    $endProp = 'DUE';
+                } elseif ($parentComponent->name === 'VEVENT') {
+                    $endProp = 'DTEND';
+                } else {
+                    throw new InvalidDataException('time-range filters on VALARM components are only supported when they are a child of VTODO or VEVENT');
+                }
+
+                if (isset($parentComponent->$endProp)) {
+                    $effectiveTrigger = $parentComponent->$endProp->getDateTime();
+                    $effectiveTrigger = $effectiveTrigger->add($triggerDuration);
+                } elseif (isset($parentComponent->DURATION)) {
+                    $effectiveTrigger = $parentComponent->DTSTART->getDateTime();
+                    $duration = VObject\DateTimeParser::parseDuration($parentComponent->DURATION);
+                    $effectiveTrigger = $effectiveTrigger->add($duration);
+                    $effectiveTrigger = $effectiveTrigger->add($triggerDuration);
+                } else {
+                    $effectiveTrigger = $parentComponent->DTSTART->getDateTime();
+                    $effectiveTrigger = $effectiveTrigger->add($triggerDuration);
+                }
+            }
+        } else {
+            $effectiveTrigger = $trigger->getDateTime();
+        }
+        return $effectiveTrigger;
+
+    }
+
+    /**
+     * Returns true or false depending on if the event falls in the specified
+     * time-range. This is used for filtering purposes.
+     *
+     * The rules used to determine if an event falls within the specified
+     * time-range is based on the CalDAV specification.
+     *
+     * @param DateTime $start
+     * @param DateTime $end
+     *
+     * @return bool
+     */
+    function isInTimeRange(DateTimeInterface $start, DateTimeInterface $end) {
+
+        $effectiveTrigger = $this->getEffectiveTriggerTime();
+
+        if (isset($this->DURATION)) {
+            $duration = VObject\DateTimeParser::parseDuration($this->DURATION);
+            $repeat = (string)$this->REPEAT;
+            if (!$repeat) {
+                $repeat = 1;
+            }
+
+            $period = new \DatePeriod($effectiveTrigger, $duration, (int)$repeat);
+
+            foreach ($period as $occurrence) {
+
+                if ($start <= $occurrence && $end > $occurrence) {
+                    return true;
+                }
+            }
+            return false;
+        } else {
+            return ($start <= $effectiveTrigger && $end > $effectiveTrigger);
+        }
+
+    }
+
+    /**
+     * A simple list of validation rules.
+     *
+     * This is simply a list of properties, and how many times they either
+     * must or must not appear.
+     *
+     * Possible values per property:
+     *   * 0 - Must not appear.
+     *   * 1 - Must appear exactly once.
+     *   * + - Must appear at least once.
+     *   * * - Can appear any number of times.
+     *   * ? - May appear, but not more than once.
+     *
+     * @var array
+     */
+    function getValidationRules() {
+
+        return [
+            'ACTION'  => 1,
+            'TRIGGER' => 1,
+
+            'DURATION' => '?',
+            'REPEAT'   => '?',
+
+            'ATTACH' => '?',
+        ];
+
+    }
+
+}
diff --git a/vendor/sabre/vobject/lib/Component/VAvailability.php b/vendor/sabre/vobject/lib/Component/VAvailability.php
new file mode 100644
index 000000000..66b3310c5
--- /dev/null
+++ b/vendor/sabre/vobject/lib/Component/VAvailability.php
@@ -0,0 +1,156 @@
+<?php
+
+namespace Sabre\VObject\Component;
+
+use DateTimeInterface;
+use Sabre\VObject;
+
+/**
+ * The VAvailability component.
+ *
+ * This component adds functionality to a component, specific for VAVAILABILITY
+ * components.
+ *
+ * @copyright Copyright (C) fruux GmbH (https://fruux.com/)
+ * @author Ivan Enderlin
+ * @license http://sabre.io/license/ Modified BSD License
+ */
+class VAvailability extends VObject\Component {
+
+    /**
+     * Returns true or false depending on if the event falls in the specified
+     * time-range. This is used for filtering purposes.
+     *
+     * The rules used to determine if an event falls within the specified
+     * time-range is based on:
+     *
+     * https://tools.ietf.org/html/draft-daboo-calendar-availability-05#section-3.1
+     *
+     * @param DateTimeInterface $start
+     * @param DateTimeInterface $end
+     *
+     * @return bool
+     */
+    function isInTimeRange(DateTimeInterface $start, DateTimeInterface $end) {
+
+        list($effectiveStart, $effectiveEnd) = $this->getEffectiveStartEnd();
+        return (
+            (is_null($effectiveStart) || $start < $effectiveEnd) &&
+            (is_null($effectiveEnd) || $end > $effectiveStart)
+        );
+
+    }
+
+    /**
+     * Returns the 'effective start' and 'effective end' of this VAVAILABILITY
+     * component.
+     *
+     * We use the DTSTART and DTEND or DURATION to determine this.
+     *
+     * The returned value is an array containing DateTimeImmutable instances.
+     * If either the start or end is 'unbounded' its value will be null
+     * instead.
+     *
+     * @return array
+     */
+    function getEffectiveStartEnd() {
+
+        $effectiveStart = null;
+        $effectiveEnd = null;
+
+        if (isset($this->DTSTART)) {
+            $effectiveStart = $this->DTSTART->getDateTime();
+        }
+        if (isset($this->DTEND)) {
+            $effectiveEnd = $this->DTEND->getDateTime();
+        } elseif ($effectiveStart && isset($this->DURATION)) {
+            $effectiveEnd = $effectiveStart->add(VObject\DateTimeParser::parseDuration($this->DURATION));
+        }
+
+        return [$effectiveStart, $effectiveEnd];
+
+    }
+
+
+    /**
+     * A simple list of validation rules.
+     *
+     * This is simply a list of properties, and how many times they either
+     * must or must not appear.
+     *
+     * Possible values per property:
+     *   * 0 - Must not appear.
+     *   * 1 - Must appear exactly once.
+     *   * + - Must appear at least once.
+     *   * * - Can appear any number of times.
+     *   * ? - May appear, but not more than once.
+     *
+     * @var array
+     */
+    function getValidationRules() {
+
+        return [
+            'UID'     => 1,
+            'DTSTAMP' => 1,
+
+            'BUSYTYPE'      => '?',
+            'CLASS'         => '?',
+            'CREATED'       => '?',
+            'DESCRIPTION'   => '?',
+            'DTSTART'       => '?',
+            'LAST-MODIFIED' => '?',
+            'ORGANIZER'     => '?',
+            'PRIORITY'      => '?',
+            'SEQUENCE'      => '?',
+            'SUMMARY'       => '?',
+            'URL'           => '?',
+            'DTEND'         => '?',
+            'DURATION'      => '?',
+
+            'CATEGORIES' => '*',
+            'COMMENT'    => '*',
+            'CONTACT'    => '*',
+        ];
+
+    }
+
+    /**
+     * Validates the node for correctness.
+     *
+     * The following options are supported:
+     *   Node::REPAIR - May attempt to automatically repair the problem.
+     *   Node::PROFILE_CARDDAV - Validate the vCard for CardDAV purposes.
+     *   Node::PROFILE_CALDAV - Validate the iCalendar for CalDAV purposes.
+     *
+     * This method returns an array with detected problems.
+     * Every element has the following properties:
+     *
+     *  * level - problem level.
+     *  * message - A human-readable string describing the issue.
+     *  * node - A reference to the problematic node.
+     *
+     * The level means:
+     *   1 - The issue was repaired (only happens if REPAIR was turned on).
+     *   2 - A warning.
+     *   3 - An error.
+     *
+     * @param int $options
+     *
+     * @return array
+     */
+    function validate($options = 0) {
+
+        $result = parent::validate($options);
+
+        if (isset($this->DTEND) && isset($this->DURATION)) {
+            $result[] = [
+                'level'   => 3,
+                'message' => 'DTEND and DURATION cannot both be present',
+                'node'    => $this
+            ];
+        }
+
+        return $result;
+
+    }
+}
diff --git a/vendor/sabre/vobject/lib/Component/VCalendar.php b/vendor/sabre/vobject/lib/Component/VCalendar.php
new file mode 100644
index 000000000..988db9dc2
--- /dev/null
+++ b/vendor/sabre/vobject/lib/Component/VCalendar.php
@@ -0,0 +1,561 @@
+<?php
+
+namespace Sabre\VObject\Component;
+
+use DateTimeInterface;
+use DateTimeZone;
+use Sabre\VObject;
+use Sabre\VObject\Component;
+use Sabre\VObject\Property;
+use Sabre\VObject\Recur\EventIterator;
+use Sabre\VObject\Recur\NoInstancesException;
+use Sabre\VObject\InvalidDataException;
+
+/**
+ * The VCalendar component.
+ *
+ * This component adds functionality to a component, specific for a VCALENDAR.
+ *
+ * @copyright Copyright (C) fruux GmbH (https://fruux.com/)
+ * @author Evert Pot (http://evertpot.com/)
+ * @license http://sabre.io/license/ Modified BSD License
+ */
+class VCalendar extends VObject\Document {
+
+    /**
+     * The default name for this component.
+     *
+     * This should be 'VCALENDAR' or 'VCARD'.
+     *
+     * @var string
+     */
+    static $defaultName = 'VCALENDAR';
+
+    /**
+     * This is a list of components, and which classes they should map to.
+     *
+     * @var array
+     */
+    static $componentMap = [
+        'VCALENDAR'     => 'Sabre\\VObject\\Component\\VCalendar',
+        'VALARM'        => 'Sabre\\VObject\\Component\\VAlarm',
+        'VEVENT'        => 'Sabre\\VObject\\Component\\VEvent',
+        'VFREEBUSY'     => 'Sabre\\VObject\\Component\\VFreeBusy',
+        'VAVAILABILITY' => 'Sabre\\VObject\\Component\\VAvailability',
+        'AVAILABLE'     => 'Sabre\\VObject\\Component\\Available',
+        'VJOURNAL'      => 'Sabre\\VObject\\Component\\VJournal',
+        'VTIMEZONE'     => 'Sabre\\VObject\\Component\\VTimeZone',
+        'VTODO'         => 'Sabre\\VObject\\Component\\VTodo',
+    ];
+
+    /**
+     * List of value-types, and which classes they map to.
+     *
+     * @var array
+     */
+    static $valueMap = [
+        'BINARY'           => 'Sabre\\VObject\\Property\\Binary',
+        'BOOLEAN'          => 'Sabre\\VObject\\Property\\Boolean',
+        'CAL-ADDRESS'      => 'Sabre\\VObject\\Property\\ICalendar\\CalAddress',
+        'DATE'             => 'Sabre\\VObject\\Property\\ICalendar\\Date',
+        'DATE-TIME'        => 'Sabre\\VObject\\Property\\ICalendar\\DateTime',
+        'DURATION'         => 'Sabre\\VObject\\Property\\ICalendar\\Duration',
+        'FLOAT'            => 'Sabre\\VObject\\Property\\FloatValue',
+        'INTEGER'          => 'Sabre\\VObject\\Property\\IntegerValue',
+        'PERIOD'           => 'Sabre\\VObject\\Property\\ICalendar\\Period',
+        'RECUR'            => 'Sabre\\VObject\\Property\\ICalendar\\Recur',
+        'TEXT'             => 'Sabre\\VObject\\Property\\Text',
+        'TIME'             => 'Sabre\\VObject\\Property\\Time',
+        'UNKNOWN'          => 'Sabre\\VObject\\Property\\Unknown', // jCard / jCal-only.
+        'URI'              => 'Sabre\\VObject\\Property\\Uri',
+        'UTC-OFFSET'       => 'Sabre\\VObject\\Property\\UtcOffset',
+    ];
+
+    /**
+     * List of properties, and which classes they map to.
+     *
+     * @var array
+     */
+    static $propertyMap = [
+        // Calendar properties
+        'CALSCALE'      => 'Sabre\\VObject\\Property\\FlatText',
+        'METHOD'        => 'Sabre\\VObject\\Property\\FlatText',
+        'PRODID'        => 'Sabre\\VObject\\Property\\FlatText',
+        'VERSION'       => 'Sabre\\VObject\\Property\\FlatText',
+
+        // Component properties
+        'ATTACH'            => 'Sabre\\VObject\\Property\\Uri',
+        'CATEGORIES'        => 'Sabre\\VObject\\Property\\Text',
+        'CLASS'             => 'Sabre\\VObject\\Property\\FlatText',
+        'COMMENT'           => 'Sabre\\VObject\\Property\\FlatText',
+        'DESCRIPTION'       => 'Sabre\\VObject\\Property\\FlatText',
+        'GEO'               => 'Sabre\\VObject\\Property\\FloatValue',
+        'LOCATION'          => 'Sabre\\VObject\\Property\\FlatText',
+        'PERCENT-COMPLETE'  => 'Sabre\\VObject\\Property\\IntegerValue',
+        'PRIORITY'          => 'Sabre\\VObject\\Property\\IntegerValue',
+        'RESOURCES'         => 'Sabre\\VObject\\Property\\Text',
+        'STATUS'            => 'Sabre\\VObject\\Property\\FlatText',
+        'SUMMARY'           => 'Sabre\\VObject\\Property\\FlatText',
+
+        // Date and Time Component Properties
+        'COMPLETED'     => 'Sabre\\VObject\\Property\\ICalendar\\DateTime',
+        'DTEND'         => 'Sabre\\VObject\\Property\\ICalendar\\DateTime',
+        'DUE'           => 'Sabre\\VObject\\Property\\ICalendar\\DateTime',
+        'DTSTART'       => 'Sabre\\VObject\\Property\\ICalendar\\DateTime',
+        'DURATION'      => 'Sabre\\VObject\\Property\\ICalendar\\Duration',
+        'FREEBUSY'      => 'Sabre\\VObject\\Property\\ICalendar\\Period',
+        'TRANSP'        => 'Sabre\\VObject\\Property\\FlatText',
+
+        // Time Zone Component Properties
+        'TZID'          => 'Sabre\\VObject\\Property\\FlatText',
+        'TZNAME'        => 'Sabre\\VObject\\Property\\FlatText',
+        'TZOFFSETFROM'  => 'Sabre\\VObject\\Property\\UtcOffset',
+        'TZOFFSETTO'    => 'Sabre\\VObject\\Property\\UtcOffset',
+        'TZURL'         => 'Sabre\\VObject\\Property\\Uri',
+
+        // Relationship Component Properties
+        'ATTENDEE'      => 'Sabre\\VObject\\Property\\ICalendar\\CalAddress',
+        'CONTACT'       => 'Sabre\\VObject\\Property\\FlatText',
+        'ORGANIZER'     => 'Sabre\\VObject\\Property\\ICalendar\\CalAddress',
+        'RECURRENCE-ID' => 'Sabre\\VObject\\Property\\ICalendar\\DateTime',
+        'RELATED-TO'    => 'Sabre\\VObject\\Property\\FlatText',
+        'URL'           => 'Sabre\\VObject\\Property\\Uri',
+        'UID'           => 'Sabre\\VObject\\Property\\FlatText',
+
+        // Recurrence Component Properties
+        'EXDATE'        => 'Sabre\\VObject\\Property\\ICalendar\\DateTime',
+        'RDATE'         => 'Sabre\\VObject\\Property\\ICalendar\\DateTime',
+        'RRULE'         => 'Sabre\\VObject\\Property\\ICalendar\\Recur',
+        'EXRULE'        => 'Sabre\\VObject\\Property\\ICalendar\\Recur', // Deprecated since rfc5545
+
+        // Alarm Component Properties
+        'ACTION'        => 'Sabre\\VObject\\Property\\FlatText',
+        'REPEAT'        => 'Sabre\\VObject\\Property\\IntegerValue',
+        'TRIGGER'       => 'Sabre\\VObject\\Property\\ICalendar\\Duration',
+
+        // Change Management Component Properties
+        'CREATED'       => 'Sabre\\VObject\\Property\\ICalendar\\DateTime',
+        'DTSTAMP'       => 'Sabre\\VObject\\Property\\ICalendar\\DateTime',
+        'LAST-MODIFIED' => 'Sabre\\VObject\\Property\\ICalendar\\DateTime',
+        'SEQUENCE'      => 'Sabre\\VObject\\Property\\IntegerValue',
+
+        // Request Status
+        'REQUEST-STATUS' => 'Sabre\\VObject\\Property\\Text',
+
+        // Additions from draft-daboo-valarm-extensions-04
+        'ALARM-AGENT'    => 'Sabre\\VObject\\Property\\Text',
+        'ACKNOWLEDGED'   => 'Sabre\\VObject\\Property\\ICalendar\\DateTime',
+        'PROXIMITY'      => 'Sabre\\VObject\\Property\\Text',
+        'DEFAULT-ALARM'  => 'Sabre\\VObject\\Property\\Boolean',
+
+        // Additions from draft-daboo-calendar-availability-05
+        'BUSYTYPE'       => 'Sabre\\VObject\\Property\\Text',
+
+    ];
+
+    /**
+     * Returns the current document type.
+     *
+     * @return int
+     */
+    function getDocumentType() {
+
+        return self::ICALENDAR20;
+
+    }
+
+    /**
+     * Returns a list of all 'base components'. For instance, if an Event has
+     * a recurrence rule, and one instance is overridden, the overridden event
+     * will have the same UID, but will be excluded from this list.
+     *
+     * VTIMEZONE components will always be excluded.
+     *
+     * @param string $componentName filter by component name
+     *
+     * @return VObject\Component[]
+     */
+    function getBaseComponents($componentName = null) {
+
+        $isBaseComponent = function($component) {
+
+            if (!$component instanceof VObject\Component) {
+                return false;
+            }
+            if ($component->name === 'VTIMEZONE') {
+                return false;
+            }
+            if (isset($component->{'RECURRENCE-ID'})) {
+                return false;
+            }
+            return true;
+
+        };
+
+        if ($componentName) {
+            // Early exit
+            return array_filter(
+                $this->select($componentName),
+                $isBaseComponent
+            );
+        }
+
+        $components = [];
+        foreach ($this->children as $childGroup) {
+
+            foreach ($childGroup as $child) {
+
+                if (!$child instanceof Component) {
+                    // If one child is not a component, they all are so we skip
+                    // the entire group.
+                    continue 2;
+                }
+                if ($isBaseComponent($child)) {
+                    $components[] = $child;
+                }
+
+            }
+
+        }
+        return $components;
+
+    }
+
+    /**
+     * Returns the first component that is not a VTIMEZONE, and does not have
+     * an RECURRENCE-ID.
+     *
+     * If there is no such component, null will be returned.
+     *
+     * @param string $componentName filter by component name
+     *
+     * @return VObject\Component|null
+     */
+    function getBaseComponent($componentName = null) {
+
+        $isBaseComponent = function($component) {
+
+            if (!$component instanceof VObject\Component) {
+                return false;
+            }
+            if ($component->name === 'VTIMEZONE') {
+                return false;
+            }
+            if (isset($component->{'RECURRENCE-ID'})) {
+                return false;
+            }
+            return true;
+
+        };
+
+        if ($componentName) {
+            foreach ($this->select($componentName) as $child) {
+                if ($isBaseComponent($child)) {
+                    return $child;
+                }
+            }
+            return null;
+        }
+
+        // Searching all components
+        foreach ($this->children as $childGroup) {
+            foreach ($childGroup as $child) {
+                if ($isBaseComponent($child)) {
+                    return $child;
+                }
+            }
+
+        }
+        return null;
+
+    }
+
+    /**
+     * Expand all events in this VCalendar object and return a new VCalendar
+     * with the expanded events.
+     *
+     * If this calendar object, has events with recurrence rules, this method
+     * can be used to expand the event into multiple sub-events.
+     *
+     * Each event will be stripped from it's recurrence information, and only
+     * the instances of the event in the specified timerange will be left
+     * alone.
+     *
+     * In addition, this method will cause timezone information to be stripped,
+     * and normalized to UTC.
+     *
+     * @param DateTimeInterface $start
+     * @param DateTimeInterface $end
+     * @param DateTimeZone $timeZone reference timezone for floating dates and
+     *                     times.
+     * @return VCalendar
+     */
+    function expand(DateTimeInterface $start, DateTimeInterface $end, DateTimeZone $timeZone = null) {
+
+        $newChildren = [];
+        $recurringEvents = [];
+
+        if (!$timeZone) {
+            $timeZone = new DateTimeZone('UTC');
+        }
+
+        $stripTimezones = function(Component $component) use ($timeZone, &$stripTimezones) {
+
+            foreach ($component->children() as $componentChild) {
+                if ($componentChild instanceof Property\ICalendar\DateTime && $componentChild->hasTime()) {
+
+                    $dt = $componentChild->getDateTimes($timeZone);
+                    // We only need to update the first timezone, because
+                    // setDateTimes will match all other timezones to the
+                    // first.
+                    $dt[0] = $dt[0]->setTimeZone(new DateTimeZone('UTC'));
+                    $componentChild->setDateTimes($dt);
+                } elseif ($componentChild instanceof Component) {
+                    $stripTimezones($componentChild);
+                }
+
+            }
+            return $component;
+
+        };
+
+        foreach ($this->children() as $child) {
+
+            if ($child instanceof Property && $child->name !== 'PRODID') {
+                // We explictly want to ignore PRODID, because we want to
+                // overwrite it with our own.
+                $newChildren[] = clone $child;
+            } elseif ($child instanceof Component && $child->name !== 'VTIMEZONE') {
+
+                // We're also stripping all VTIMEZONE objects because we're
+                // converting everything to UTC.
+                if ($child->name === 'VEVENT' && (isset($child->{'RECURRENCE-ID'}) || isset($child->RRULE) || isset($child->RDATE))) {
+                    // Handle these a bit later.
+                    $uid = (string)$child->UID;
+                    if (!$uid) {
+                        throw new InvalidDataException('Every VEVENT object must have a UID property');
+                    }
+                    if (isset($recurringEvents[$uid])) {
+                        $recurringEvents[$uid][] = clone $child;
+                    } else {
+                        $recurringEvents[$uid] = [clone $child];
+                    }
+                } elseif ($child->name === 'VEVENT' && $child->isInTimeRange($start, $end)) {
+                    $newChildren[] = $stripTimezones(clone $child);
+                }
+
+            }
+
+        }
+
+        foreach ($recurringEvents as $events) {
+
+            try {
+                $it = new EventIterator($events, $timeZone);
+
+            } catch (NoInstancesException $e) {
+                // This event is recurring, but it doesn't have a single
+                // instance. We are skipping this event from the output
+                // entirely.
+                continue;
+            }
+            $it->fastForward($start);
+
+            while ($it->valid() && $it->getDTStart() < $end) {
+
+                if ($it->getDTEnd() > $start) {
+
+                    $newChildren[] = $stripTimezones($it->getEventObject());
+
+                }
+                $it->next();
+
+            }
+
+        }
+
+        return new self($newChildren);
+
+    }
+
+    /**
+     * This method should return a list of default property values.
+     *
+     * @return array
+     */
+    protected function getDefaults() {
+
+        return [
+            'VERSION'  => '2.0',
+            'PRODID'   => '-//Sabre//Sabre VObject ' . VObject\Version::VERSION . '//EN',
+            'CALSCALE' => 'GREGORIAN',
+        ];
+
+    }
+
+    /**
+     * A simple list of validation rules.
+     *
+     * This is simply a list of properties, and how many times they either
+     * must or must not appear.
+     *
+     * Possible values per property:
+     *   * 0 - Must not appear.
+     *   * 1 - Must appear exactly once.
+     *   * + - Must appear at least once.
+     *   * * - Can appear any number of times.
+     *   * ? - May appear, but not more than once.
+     *
+     * @var array
+     */
+    function getValidationRules() {
+
+        return [
+            'PRODID'  => 1,
+            'VERSION' => 1,
+
+            'CALSCALE' => '?',
+            'METHOD'   => '?',
+        ];
+
+    }
+
+    /**
+     * Validates the node for correctness.
+     *
+     * The following options are supported:
+     *   Node::REPAIR - May attempt to automatically repair the problem.
+     *   Node::PROFILE_CARDDAV - Validate the vCard for CardDAV purposes.
+     *   Node::PROFILE_CALDAV - Validate the iCalendar for CalDAV purposes.
+     *
+     * This method returns an array with detected problems.
+     * Every element has the following properties:
+     *
+     *  * level - problem level.
+     *  * message - A human-readable string describing the issue.
+     *  * node - A reference to the problematic node.
+     *
+     * The level means:
+     *   1 - The issue was repaired (only happens if REPAIR was turned on).
+     *   2 - A warning.
+     *   3 - An error.
+     *
+     * @param int $options
+     *
+     * @return array
+     */
+    function validate($options = 0) {
+
+        $warnings = parent::validate($options);
+
+        if ($ver = $this->VERSION) {
+            if ((string)$ver !== '2.0') {
+                $warnings[] = [
+                    'level'   => 3,
+                    'message' => 'Only iCalendar version 2.0 as defined in rfc5545 is supported.',
+                    'node'    => $this,
+                ];
+            }
+
+        }
+
+        $uidList = [];
+        $componentsFound = 0;
+        $componentTypes = [];
+
+        foreach ($this->children() as $child) {
+            if ($child instanceof Component) {
+                $componentsFound++;
+
+                if (!in_array($child->name, ['VEVENT', 'VTODO', 'VJOURNAL'])) {
+                    continue;
+                }
+                $componentTypes[] = $child->name;
+
+                $uid = (string)$child->UID;
+                $isMaster = isset($child->{'RECURRENCE-ID'}) ? 0 : 1;
+                if (isset($uidList[$uid])) {
+                    $uidList[$uid]['count']++;
+                    if ($isMaster && $uidList[$uid]['hasMaster']) {
+                        $warnings[] = [
+                            'level'   => 3,
+                            'message' => 'More than one master object was found for the object with UID ' . $uid,
+                            'node'    => $this,
+                        ];
+                    }
+                    $uidList[$uid]['hasMaster'] += $isMaster;
+                } else {
+                    $uidList[$uid] = [
+                        'count'     => 1,
+                        'hasMaster' => $isMaster,
+                    ];
+                }
+
+            }
+        }
+
+        if ($componentsFound === 0) {
+            $warnings[] = [
+                'level'   => 3,
+                'message' => 'An iCalendar object must have at least 1 component.',
+                'node'    => $this,
+            ];
+        }
+
+        if ($options & self::PROFILE_CALDAV) {
+            if (count($uidList) > 1) {
+                $warnings[] = [
+                    'level'   => 3,
+                    'message' => 'A calendar object on a CalDAV server may only have components with the same UID.',
+                    'node'    => $this,
+                ];
+            }
+            if (count($componentTypes) === 0) {
+                $warnings[] = [
+                    'level'   => 3,
+                    'message' => 'A calendar object on a CalDAV server must have at least 1 component (VTODO, VEVENT, VJOURNAL).',
+                    'node'    => $this,
+                ];
+            }
+            if (count(array_unique($componentTypes)) > 1) {
+                $warnings[] = [
+                    'level'   => 3,
+                    'message' => 'A calendar object on a CalDAV server may only have 1 type of component (VEVENT, VTODO or VJOURNAL).',
+                    'node'    => $this,
+                ];
+            }
+
+            if (isset($this->METHOD)) {
+                $warnings[] = [
+                    'level'   => 3,
+                    'message' => 'A calendar object on a CalDAV server MUST NOT have a METHOD property.',
+                    'node'    => $this,
+                ];
+            }
+        }
+
+        return $warnings;
+
+    }
+
+    /**
+     * Returns all components with a specific UID value.
+     *
+     * @return array
+     */
+    function getByUID($uid) {
+
+        return array_filter($this->getComponents(), function($item) use ($uid) {
+
+            if (!$itemUid = $item->select('UID')) {
+                return false;
+            }
+            $itemUid = current($itemUid)->getValue();
+            return $uid === $itemUid;
+
+        });
+
+    }
+
+
+}
diff --git a/vendor/sabre/vobject/lib/Component/VCard.php b/vendor/sabre/vobject/lib/Component/VCard.php
new file mode 100644
index 000000000..3c05191a9
--- /dev/null
+++ b/vendor/sabre/vobject/lib/Component/VCard.php
@@ -0,0 +1,553 @@
+<?php
+
+namespace Sabre\VObject\Component;
+
+use Sabre\VObject;
+use Sabre\Xml;
+
+/**
+ * The VCard component.
+ *
+ * This component represents the BEGIN:VCARD and END:VCARD found in every
+ * vcard.
+ *
+ * @copyright Copyright (C) fruux GmbH (https://fruux.com/)
+ * @author Evert Pot (http://evertpot.com/)
+ * @license http://sabre.io/license/ Modified BSD License
+ */
+class VCard extends VObject\Document {
+
+    /**
+     * The default name for this component.
+     *
+     * This should be 'VCALENDAR' or 'VCARD'.
+     *
+     * @var string
+     */
+    static $defaultName = 'VCARD';
+
+    /**
+     * Caching the version number.
+     *
+     * @var int
+     */
+    private $version = null;
+
+    /**
+     * This is a list of components, and which classes they should map to.
+     *
+     * @var array
+     */
+    static $componentMap = [
+        'VCARD' => 'Sabre\\VObject\\Component\\VCard',
+    ];
+
+    /**
+     * List of value-types, and which classes they map to.
+     *
+     * @var array
+     */
+    static $valueMap = [
+        'BINARY'           => 'Sabre\\VObject\\Property\\Binary',
+        'BOOLEAN'          => 'Sabre\\VObject\\Property\\Boolean',
+        'CONTENT-ID'       => 'Sabre\\VObject\\Property\\FlatText',   // vCard 2.1 only
+        'DATE'             => 'Sabre\\VObject\\Property\\VCard\\Date',
+        'DATE-TIME'        => 'Sabre\\VObject\\Property\\VCard\\DateTime',
+        'DATE-AND-OR-TIME' => 'Sabre\\VObject\\Property\\VCard\\DateAndOrTime', // vCard only
+        'FLOAT'            => 'Sabre\\VObject\\Property\\FloatValue',
+        'INTEGER'          => 'Sabre\\VObject\\Property\\IntegerValue',
+        'LANGUAGE-TAG'     => 'Sabre\\VObject\\Property\\VCard\\LanguageTag',
+        'TIMESTAMP'        => 'Sabre\\VObject\\Property\\VCard\\TimeStamp',
+        'TEXT'             => 'Sabre\\VObject\\Property\\Text',
+        'TIME'             => 'Sabre\\VObject\\Property\\Time',
+        'UNKNOWN'          => 'Sabre\\VObject\\Property\\Unknown', // jCard / jCal-only.
+        'URI'              => 'Sabre\\VObject\\Property\\Uri',
+        'URL'              => 'Sabre\\VObject\\Property\\Uri', // vCard 2.1 only
+        'UTC-OFFSET'       => 'Sabre\\VObject\\Property\\UtcOffset',
+    ];
+
+    /**
+     * List of properties, and which classes they map to.
+     *
+     * @var array
+     */
+    static $propertyMap = [
+
+        // vCard 2.1 properties and up
+        'N'       => 'Sabre\\VObject\\Property\\Text',
+        'FN'      => 'Sabre\\VObject\\Property\\FlatText',
+        'PHOTO'   => 'Sabre\\VObject\\Property\\Binary',
+        'BDAY'    => 'Sabre\\VObject\\Property\\VCard\\DateAndOrTime',
+        'ADR'     => 'Sabre\\VObject\\Property\\Text',
+        'LABEL'   => 'Sabre\\VObject\\Property\\FlatText', // Removed in vCard 4.0
+        'TEL'     => 'Sabre\\VObject\\Property\\FlatText',
+        'EMAIL'   => 'Sabre\\VObject\\Property\\FlatText',
+        'MAILER'  => 'Sabre\\VObject\\Property\\FlatText', // Removed in vCard 4.0
+        'GEO'     => 'Sabre\\VObject\\Property\\FlatText',
+        'TITLE'   => 'Sabre\\VObject\\Property\\FlatText',
+        'ROLE'    => 'Sabre\\VObject\\Property\\FlatText',
+        'LOGO'    => 'Sabre\\VObject\\Property\\Binary',
+        // 'AGENT'   => 'Sabre\\VObject\\Property\\',      // Todo: is an embedded vCard. Probably rare, so
+                                 // not supported at the moment
+        'ORG'     => 'Sabre\\VObject\\Property\\Text',
+        'NOTE'    => 'Sabre\\VObject\\Property\\FlatText',
+        'REV'     => 'Sabre\\VObject\\Property\\VCard\\TimeStamp',
+        'SOUND'   => 'Sabre\\VObject\\Property\\FlatText',
+        'URL'     => 'Sabre\\VObject\\Property\\Uri',
+        'UID'     => 'Sabre\\VObject\\Property\\FlatText',
+        'VERSION' => 'Sabre\\VObject\\Property\\FlatText',
+        'KEY'     => 'Sabre\\VObject\\Property\\FlatText',
+        'TZ'      => 'Sabre\\VObject\\Property\\Text',
+
+        // vCard 3.0 properties
+        'CATEGORIES'  => 'Sabre\\VObject\\Property\\Text',
+        'SORT-STRING' => 'Sabre\\VObject\\Property\\FlatText',
+        'PRODID'      => 'Sabre\\VObject\\Property\\FlatText',
+        'NICKNAME'    => 'Sabre\\VObject\\Property\\Text',
+        'CLASS'       => 'Sabre\\VObject\\Property\\FlatText', // Removed in vCard 4.0
+
+        // rfc2739 properties
+        'FBURL'        => 'Sabre\\VObject\\Property\\Uri',
+        'CAPURI'       => 'Sabre\\VObject\\Property\\Uri',
+        'CALURI'       => 'Sabre\\VObject\\Property\\Uri',
+        'CALADRURI'    => 'Sabre\\VObject\\Property\\Uri',
+
+        // rfc4770 properties
+        'IMPP'         => 'Sabre\\VObject\\Property\\Uri',
+
+        // vCard 4.0 properties
+        'SOURCE'       => 'Sabre\\VObject\\Property\\Uri',
+        'XML'          => 'Sabre\\VObject\\Property\\FlatText',
+        'ANNIVERSARY'  => 'Sabre\\VObject\\Property\\VCard\\DateAndOrTime',
+        'CLIENTPIDMAP' => 'Sabre\\VObject\\Property\\Text',
+        'LANG'         => 'Sabre\\VObject\\Property\\VCard\\LanguageTag',
+        'GENDER'       => 'Sabre\\VObject\\Property\\Text',
+        'KIND'         => 'Sabre\\VObject\\Property\\FlatText',
+        'MEMBER'       => 'Sabre\\VObject\\Property\\Uri',
+        'RELATED'      => 'Sabre\\VObject\\Property\\Uri',
+
+        // rfc6474 properties
+        'BIRTHPLACE'    => 'Sabre\\VObject\\Property\\FlatText',
+        'DEATHPLACE'    => 'Sabre\\VObject\\Property\\FlatText',
+        'DEATHDATE'     => 'Sabre\\VObject\\Property\\VCard\\DateAndOrTime',
+
+        // rfc6715 properties
+        'EXPERTISE'     => 'Sabre\\VObject\\Property\\FlatText',
+        'HOBBY'         => 'Sabre\\VObject\\Property\\FlatText',
+        'INTEREST'      => 'Sabre\\VObject\\Property\\FlatText',
+        'ORG-DIRECTORY' => 'Sabre\\VObject\\Property\\FlatText',
+
+    ];
+
+    /**
+     * Returns the current document type.
+     *
+     * @return int
+     */
+    function getDocumentType() {
+
+        if (!$this->version) {
+
+            $version = (string)$this->VERSION;
+
+            switch ($version) {
+                case '2.1' :
+                    $this->version = self::VCARD21;
+                    break;
+                case '3.0' :
+                    $this->version = self::VCARD30;
+                    break;
+                case '4.0' :
+                    $this->version = self::VCARD40;
+                    break;
+                default :
+                    // We don't want to cache the version if it's unknown,
+                    // because we might get a version property in a bit.
+                    return self::UNKNOWN;
+            }
+        }
+
+        return $this->version;
+
+    }
+
+    /**
+     * Converts the document to a different vcard version.
+     *
+     * Use one of the VCARD constants for the target. This method will return
+     * a copy of the vcard in the new version.
+     *
+     * At the moment the only supported conversion is from 3.0 to 4.0.
+     *
+     * If input and output version are identical, a clone is returned.
+     *
+     * @param int $target
+     *
+     * @return VCard
+     */
+    function convert($target) {
+
+        $converter = new VObject\VCardConverter();
+        return $converter->convert($this, $target);
+
+    }
+
+    /**
+     * VCards with version 2.1, 3.0 and 4.0 are found.
+     *
+     * If the VCARD doesn't know its version, 2.1 is assumed.
+     */
+    const DEFAULT_VERSION = self::VCARD21;
+
+    /**
+     * Validates the node for correctness.
+     *
+     * The following options are supported:
+     *   Node::REPAIR - May attempt to automatically repair the problem.
+     *
+     * This method returns an array with detected problems.
+     * Every element has the following properties:
+     *
+     *  * level - problem level.
+     *  * message - A human-readable string describing the issue.
+     *  * node - A reference to the problematic node.
+     *
+     * The level means:
+     *   1 - The issue was repaired (only happens if REPAIR was turned on)
+     *   2 - An inconsequential issue
+     *   3 - A severe issue.
+     *
+     * @param int $options
+     *
+     * @return array
+     */
+    function validate($options = 0) {
+
+        $warnings = [];
+
+        $versionMap = [
+            self::VCARD21 => '2.1',
+            self::VCARD30 => '3.0',
+            self::VCARD40 => '4.0',
+        ];
+
+        $version = $this->select('VERSION');
+        if (count($version) === 1) {
+            $version = (string)$this->VERSION;
+            if ($version !== '2.1' && $version !== '3.0' && $version !== '4.0') {
+                $warnings[] = [
+                    'level'   => 3,
+                    'message' => 'Only vcard version 4.0 (RFC6350), version 3.0 (RFC2426) or version 2.1 (icm-vcard-2.1) are supported.',
+                    'node'    => $this,
+                ];
+                if ($options & self::REPAIR) {
+                    $this->VERSION = $versionMap[self::DEFAULT_VERSION];
+                }
+            }
+            if ($version === '2.1' && ($options & self::PROFILE_CARDDAV)) {
+                $warnings[] = [
+                    'level'   => 3,
+                    'message' => 'CardDAV servers are not allowed to accept vCard 2.1.',
+                    'node'    => $this,
+                ];
+            }
+
+        }
+        $uid = $this->select('UID');
+        if (count($uid) === 0) {
+            if ($options & self::PROFILE_CARDDAV) {
+                // Required for CardDAV
+                $warningLevel = 3;
+                $message = 'vCards on CardDAV servers MUST have a UID property.';
+            } else {
+                // Not required for regular vcards
+                $warningLevel = 2;
+                $message = 'Adding a UID to a vCard property is recommended.';
+            }
+            if ($options & self::REPAIR) {
+                $this->UID = VObject\UUIDUtil::getUUID();
+                $warningLevel = 1;
+            }
+            $warnings[] = [
+                'level'   => $warningLevel,
+                'message' => $message,
+                'node'    => $this,
+            ];
+        }
+
+        $fn = $this->select('FN');
+        if (count($fn) !== 1) {
+
+            $repaired = false;
+            if (($options & self::REPAIR) && count($fn) === 0) {
+                // We're going to try to see if we can use the contents of the
+                // N property.
+                if (isset($this->N)) {
+                    $value = explode(';', (string)$this->N);
+                    if (isset($value[1]) && $value[1]) {
+                        $this->FN = $value[1] . ' ' . $value[0];
+                    } else {
+                        $this->FN = $value[0];
+                    }
+                    $repaired = true;
+
+                // Otherwise, the ORG property may work
+                } elseif (isset($this->ORG)) {
+                    $this->FN = (string)$this->ORG;
+                    $repaired = true;
+                }
+
+            }
+            $warnings[] = [
+                'level'   => $repaired ? 1 : 3,
+                'message' => 'The FN property must appear in the VCARD component exactly 1 time',
+                'node'    => $this,
+            ];
+        }
+
+        return array_merge(
+            parent::validate($options),
+            $warnings
+        );
+
+    }
+
+    /**
+     * A simple list of validation rules.
+     *
+     * This is simply a list of properties, and how many times they either
+     * must or must not appear.
+     *
+     * Possible values per property:
+     *   * 0 - Must not appear.
+     *   * 1 - Must appear exactly once.
+     *   * + - Must appear at least once.
+     *   * * - Can appear any number of times.
+     *   * ? - May appear, but not more than once.
+     *
+     * @var array
+     */
+    function getValidationRules() {
+
+        return [
+            'ADR'          => '*',
+            'ANNIVERSARY'  => '?',
+            'BDAY'         => '?',
+            'CALADRURI'    => '*',
+            'CALURI'       => '*',
+            'CATEGORIES'   => '*',
+            'CLIENTPIDMAP' => '*',
+            'EMAIL'        => '*',
+            'FBURL'        => '*',
+            'IMPP'         => '*',
+            'GENDER'       => '?',
+            'GEO'          => '*',
+            'KEY'          => '*',
+            'KIND'         => '?',
+            'LANG'         => '*',
+            'LOGO'         => '*',
+            'MEMBER'       => '*',
+            'N'            => '?',
+            'NICKNAME'     => '*',
+            'NOTE'         => '*',
+            'ORG'          => '*',
+            'PHOTO'        => '*',
+            'PRODID'       => '?',
+            'RELATED'      => '*',
+            'REV'          => '?',
+            'ROLE'         => '*',
+            'SOUND'        => '*',
+            'SOURCE'       => '*',
+            'TEL'          => '*',
+            'TITLE'        => '*',
+            'TZ'           => '*',
+            'URL'          => '*',
+            'VERSION'      => '1',
+            'XML'          => '*',
+
+            // FN is commented out, because it's already handled by the
+            // validate function, which may also try to repair it.
+            // 'FN'           => '+',
+            'UID'          => '?',
+        ];
+
+    }
+
+    /**
+     * Returns a preferred field.
+     *
+     * VCards can indicate wether a field such as ADR, TEL or EMAIL is
+     * preferred by specifying TYPE=PREF (vcard 2.1, 3) or PREF=x (vcard 4, x
+     * being a number between 1 and 100).
+     *
+     * If neither of those parameters are specified, the first is returned, if
+     * a field with that name does not exist, null is returned.
+     *
+     * @param string $fieldName
+     *
+     * @return VObject\Property|null
+     */
+    function preferred($propertyName) {
+
+        $preferred = null;
+        $lastPref = 101;
+        foreach ($this->select($propertyName) as $field) {
+
+            $pref = 101;
+            if (isset($field['TYPE']) && $field['TYPE']->has('PREF')) {
+                $pref = 1;
+            } elseif (isset($field['PREF'])) {
+                $pref = $field['PREF']->getValue();
+            }
+
+            if ($pref < $lastPref || is_null($preferred)) {
+                $preferred = $field;
+                $lastPref = $pref;
+            }
+
+        }
+        return $preferred;
+
+    }
+
+    /**
+     * Returns a property with a specific TYPE value (ADR, TEL, or EMAIL).
+     *
+     * This function will return null if the property does not exist. If there are
+     * multiple properties with the same TYPE value, only one will be returned.
+     *
+     * @param string $propertyName
+     * @param string $type
+     *
+     * @return VObject\Property|null
+     */
+    function getByType($propertyName, $type) {
+        foreach ($this->select($propertyName) as $field) {
+            if (isset($field['TYPE']) && $field['TYPE']->has($type)) {
+                return $field;
+            }
+        }
+    }
+
+    /**
+     * This method should return a list of default property values.
+     *
+     * @return array
+     */
+    protected function getDefaults() {
+
+        return [
+            'VERSION' => '4.0',
+            'PRODID'  => '-//Sabre//Sabre VObject ' . VObject\Version::VERSION . '//EN',
+            'UID'     => 'sabre-vobject-' . VObject\UUIDUtil::getUUID(),
+        ];
+
+    }
+
+    /**
+     * This method returns an array, with the representation as it should be
+     * encoded in json. This is used to create jCard or jCal documents.
+     *
+     * @return array
+     */
+    function jsonSerialize() {
+
+        // A vcard does not have sub-components, so we're overriding this
+        // method to remove that array element.
+        $properties = [];
+
+        foreach ($this->children() as $child) {
+            $properties[] = $child->jsonSerialize();
+        }
+
+        return [
+            strtolower($this->name),
+            $properties,
+        ];
+
+    }
+
+    /**
+     * This method serializes the data into XML. This is used to create xCard or
+     * xCal documents.
+     *
+     * @param Xml\Writer $writer  XML writer.
+     *
+     * @return void
+     */
+    function xmlSerialize(Xml\Writer $writer) {
+
+        $propertiesByGroup = [];
+
+        foreach ($this->children() as $property) {
+
+            $group = $property->group;
+
+            if (!isset($propertiesByGroup[$group])) {
+                $propertiesByGroup[$group] = [];
+            }
+
+            $propertiesByGroup[$group][] = $property;
+
+        }
+
+        $writer->startElement(strtolower($this->name));
+
+        foreach ($propertiesByGroup as $group => $properties) {
+
+            if (!empty($group)) {
+
+                $writer->startElement('group');
+                $writer->writeAttribute('name', strtolower($group));
+
+            }
+
+            foreach ($properties as $property) {
+                switch ($property->name) {
+
+                    case 'VERSION':
+                        continue;
+
+                    case 'XML':
+                        $value = $property->getParts();
+                        $fragment = new Xml\Element\XmlFragment($value[0]);
+                        $writer->write($fragment);
+                        break;
+
+                    default:
+                        $property->xmlSerialize($writer);
+                        break;
+
+                }
+            }
+
+            if (!empty($group)) {
+                $writer->endElement();
+            }
+
+        }
+
+        $writer->endElement();
+
+    }
+
+    /**
+     * Returns the default class for a property name.
+     *
+     * @param string $propertyName
+     *
+     * @return string
+     */
+    function getClassNameForPropertyName($propertyName) {
+
+        $className = parent::getClassNameForPropertyName($propertyName);
+
+        // In vCard 4, BINARY no longer exists, and we need URI instead.
+        if ($className == 'Sabre\\VObject\\Property\\Binary' && $this->getDocumentType() === self::VCARD40) {
+            return 'Sabre\\VObject\\Property\\Uri';
+        }
+        return $className;
+
+    }
+
+}
diff --git a/vendor/sabre/vobject/lib/Component/VEvent.php b/vendor/sabre/vobject/lib/Component/VEvent.php
new file mode 100644
index 000000000..7f6861190
--- /dev/null
+++ b/vendor/sabre/vobject/lib/Component/VEvent.php
@@ -0,0 +1,153 @@
+<?php
+
+namespace Sabre\VObject\Component;
+
+use DateTimeInterface;
+use Sabre\VObject;
+use Sabre\VObject\Recur\EventIterator;
+use Sabre\VObject\Recur\NoInstancesException;
+
+/**
+ * VEvent component.
+ *
+ * This component contains some additional functionality specific for VEVENT's.
+ *
+ * @copyright Copyright (C) fruux GmbH (https://fruux.com/)
+ * @author Evert Pot (http://evertpot.com/)
+ * @license http://sabre.io/license/ Modified BSD License
+ */
+class VEvent extends VObject\Component {
+
+    /**
+     * Returns true or false depending on if the event falls in the specified
+     * time-range. This is used for filtering purposes.
+     *
+     * The rules used to determine if an event falls within the specified
+     * time-range is based on the CalDAV specification.
+     *
+     * @param DateTimeInterface $start
+     * @param DateTimeInterface $end
+     *
+     * @return bool
+     */
+    function isInTimeRange(DateTimeInterface $start, DateTimeInterface $end) {
+
+        if ($this->RRULE) {
+
+            try {
+
+                $it = new EventIterator($this, null, $start->getTimezone());
+
+            } catch (NoInstancesException $e) {
+
+                // If we've catched this exception, there are no instances
+                // for the event that fall into the specified time-range.
+                return false;
+
+            }
+
+            $it->fastForward($start);
+
+            // We fast-forwarded to a spot where the end-time of the
+            // recurrence instance exceeded the start of the requested
+            // time-range.
+            //
+            // If the starttime of the recurrence did not exceed the
+            // end of the time range as well, we have a match.
+            return ($it->getDTStart() < $end && $it->getDTEnd() > $start);
+
+        }
+
+        $effectiveStart = $this->DTSTART->getDateTime($start->getTimezone());
+        if (isset($this->DTEND)) {
+
+            // The DTEND property is considered non inclusive. So for a 3 day
+            // event in july, dtstart and dtend would have to be July 1st and
+            // July 4th respectively.
+            //
+            // See:
+            // http://tools.ietf.org/html/rfc5545#page-54
+            $effectiveEnd = $this->DTEND->getDateTime($end->getTimezone());
+
+        } elseif (isset($this->DURATION)) {
+            $effectiveEnd = $effectiveStart->add(VObject\DateTimeParser::parseDuration($this->DURATION));
+        } elseif (!$this->DTSTART->hasTime()) {
+            $effectiveEnd = $effectiveStart->modify('+1 day');
+        } else {
+            $effectiveEnd = $effectiveStart;
+        }
+        return (
+            ($start < $effectiveEnd) && ($end > $effectiveStart)
+        );
+
+    }
+
+    /**
+     * This method should return a list of default property values.
+     *
+     * @return array
+     */
+    protected function getDefaults() {
+
+        return [
+            'UID'     => 'sabre-vobject-' . VObject\UUIDUtil::getUUID(),
+            'DTSTAMP' => date('Ymd\\THis\\Z'),
+        ];
+
+    }
+
+    /**
+     * A simple list of validation rules.
+     *
+     * This is simply a list of properties, and how many times they either
+     * must or must not appear.
+     *
+     * Possible values per property:
+     *   * 0 - Must not appear.
+     *   * 1 - Must appear exactly once.
+     *   * + - Must appear at least once.
+     *   * * - Can appear any number of times.
+     *   * ? - May appear, but not more than once.
+     *
+     * @var array
+     */
+    function getValidationRules() {
+
+        $hasMethod = isset($this->parent->METHOD);
+        return [
+            'UID'           => 1,
+            'DTSTAMP'       => 1,
+            'DTSTART'       => $hasMethod ? '?' : '1',
+            'CLASS'         => '?',
+            'CREATED'       => '?',
+            'DESCRIPTION'   => '?',
+            'GEO'           => '?',
+            'LAST-MODIFIED' => '?',
+            'LOCATION'      => '?',
+            'ORGANIZER'     => '?',
+            'PRIORITY'      => '?',
+            'SEQUENCE'      => '?',
+            'STATUS'        => '?',
+            'SUMMARY'       => '?',
+            'TRANSP'        => '?',
+            'URL'           => '?',
+            'RECURRENCE-ID' => '?',
+            'RRULE'         => '?',
+            'DTEND'         => '?',
+            'DURATION'      => '?',
+
+            'ATTACH'         => '*',
+            'ATTENDEE'       => '*',
+            'CATEGORIES'     => '*',
+            'COMMENT'        => '*',
+            'CONTACT'        => '*',
+            'EXDATE'         => '*',
+            'REQUEST-STATUS' => '*',
+            'RELATED-TO'     => '*',
+            'RESOURCES'      => '*',
+            'RDATE'          => '*',
+        ];
+
+    }
+
+}
diff --git a/vendor/sabre/vobject/lib/Component/VFreeBusy.php b/vendor/sabre/vobject/lib/Component/VFreeBusy.php
new file mode 100644
index 000000000..72294cc9f
--- /dev/null
+++ b/vendor/sabre/vobject/lib/Component/VFreeBusy.php
@@ -0,0 +1,102 @@
+<?php
+
+namespace Sabre\VObject\Component;
+
+use DateTimeInterface;
+use Sabre\VObject;
+
+/**
+ * The VFreeBusy component.
+ *
+ * This component adds functionality to a component, specific for VFREEBUSY
+ * components.
+ *
+ * @copyright Copyright (C) fruux GmbH (https://fruux.com/)
+ * @author Evert Pot (http://evertpot.com/)
+ * @license http://sabre.io/license/ Modified BSD License
+ */
+class VFreeBusy extends VObject\Component {
+
+    /**
+     * Checks based on the contained FREEBUSY information, if a timeslot is
+     * available.
+     *
+     * @param DateTimeInterface $start
+     * @param DateTimeInterface $end
+     *
+     * @return bool
+     */
+    function isFree(DateTimeInterface $start, DatetimeInterface $end) {
+
+        foreach ($this->select('FREEBUSY') as $freebusy) {
+
+            // We are only interested in FBTYPE=BUSY (the default),
+            // FBTYPE=BUSY-TENTATIVE or FBTYPE=BUSY-UNAVAILABLE.
+            if (isset($freebusy['FBTYPE']) && strtoupper(substr((string)$freebusy['FBTYPE'], 0, 4)) !== 'BUSY') {
+                continue;
+            }
+
+            // The freebusy component can hold more than 1 value, separated by
+            // commas.
+            $periods = explode(',', (string)$freebusy);
+
+            foreach ($periods as $period) {
+                // Every period is formatted as [start]/[end]. The start is an
+                // absolute UTC time, the end may be an absolute UTC time, or
+                // duration (relative) value.
+                list($busyStart, $busyEnd) = explode('/', $period);
+
+                $busyStart = VObject\DateTimeParser::parse($busyStart);
+                $busyEnd = VObject\DateTimeParser::parse($busyEnd);
+                if ($busyEnd instanceof \DateInterval) {
+                    $busyEnd = $busyStart->add($busyEnd);
+                }
+
+                if ($start < $busyEnd && $end > $busyStart) {
+                    return false;
+                }
+
+            }
+
+        }
+
+        return true;
+
+    }
+
+    /**
+     * A simple list of validation rules.
+     *
+     * This is simply a list of properties, and how many times they either
+     * must or must not appear.
+     *
+     * Possible values per property:
+     *   * 0 - Must not appear.
+     *   * 1 - Must appear exactly once.
+     *   * + - Must appear at least once.
+     *   * * - Can appear any number of times.
+     *   * ? - May appear, but not more than once.
+     *
+     * @var array
+     */
+    function getValidationRules() {
+
+        return [
+            'UID'     => 1,
+            'DTSTAMP' => 1,
+
+            'CONTACT'   => '?',
+            'DTSTART'   => '?',
+            'DTEND'     => '?',
+            'ORGANIZER' => '?',
+            'URL'       => '?',
+
+            'ATTENDEE'       => '*',
+            'COMMENT'        => '*',
+            'FREEBUSY'       => '*',
+            'REQUEST-STATUS' => '*',
+        ];
+
+    }
+
+}
diff --git a/vendor/sabre/vobject/lib/Component/VJournal.php b/vendor/sabre/vobject/lib/Component/VJournal.php
new file mode 100644
index 000000000..a1b1a863d
--- /dev/null
+++ b/vendor/sabre/vobject/lib/Component/VJournal.php
@@ -0,0 +1,107 @@
+<?php
+
+namespace Sabre\VObject\Component;
+
+use DateTimeInterface;
+use Sabre\VObject;
+
+/**
+ * VJournal component.
+ *
+ * This component contains some additional functionality specific for VJOURNALs.
+ *
+ * @copyright Copyright (C) fruux GmbH (https://fruux.com/)
+ * @author Evert Pot (http://evertpot.com/)
+ * @license http://sabre.io/license/ Modified BSD License
+ */
+class VJournal extends VObject\Component {
+
+    /**
+     * Returns true or false depending on if the event falls in the specified
+     * time-range. This is used for filtering purposes.
+     *
+     * The rules used to determine if an event falls within the specified
+     * time-range is based on the CalDAV specification.
+     *
+     * @param DateTimeInterface $start
+     * @param DateTimeInterface $end
+     *
+     * @return bool
+     */
+    function isInTimeRange(DateTimeInterface $start, DateTimeInterface $end) {
+
+        $dtstart = isset($this->DTSTART) ? $this->DTSTART->getDateTime() : null;
+        if ($dtstart) {
+            $effectiveEnd = $dtstart;
+            if (!$this->DTSTART->hasTime()) {
+                $effectiveEnd = $effectiveEnd->modify('+1 day');
+            }
+
+            return ($start <= $effectiveEnd && $end > $dtstart);
+
+        }
+        return false;
+
+    }
+
+    /**
+     * A simple list of validation rules.
+     *
+     * This is simply a list of properties, and how many times they either
+     * must or must not appear.
+     *
+     * Possible values per property:
+     *   * 0 - Must not appear.
+     *   * 1 - Must appear exactly once.
+     *   * + - Must appear at least once.
+     *   * * - Can appear any number of times.
+     *   * ? - May appear, but not more than once.
+     *
+     * @var array
+     */
+    function getValidationRules() {
+
+        return [
+            'UID'     => 1,
+            'DTSTAMP' => 1,
+
+            'CLASS'         => '?',
+            'CREATED'       => '?',
+            'DTSTART'       => '?',
+            'LAST-MODIFIED' => '?',
+            'ORGANIZER'     => '?',
+            'RECURRENCE-ID' => '?',
+            'SEQUENCE'      => '?',
+            'STATUS'        => '?',
+            'SUMMARY'       => '?',
+            'URL'           => '?',
+
+            'RRULE' => '?',
+
+            'ATTACH'      => '*',
+            'ATTENDEE'    => '*',
+            'CATEGORIES'  => '*',
+            'COMMENT'     => '*',
+            'CONTACT'     => '*',
+            'DESCRIPTION' => '*',
+            'EXDATE'      => '*',
+            'RELATED-TO'  => '*',
+            'RDATE'       => '*',
+        ];
+
+    }
+
+    /**
+     * This method should return a list of default property values.
+     *
+     * @return array
+     */
+    protected function getDefaults() {
+
+        return [
+            'UID'     => 'sabre-vobject-' . VObject\UUIDUtil::getUUID(),
+            'DTSTAMP' => date('Ymd\\THis\\Z'),
+        ];
+
+    }
+}
diff --git a/vendor/sabre/vobject/lib/Component/VTimeZone.php b/vendor/sabre/vobject/lib/Component/VTimeZone.php
new file mode 100644
index 000000000..d5d886947
--- /dev/null
+++ b/vendor/sabre/vobject/lib/Component/VTimeZone.php
@@ -0,0 +1,67 @@
+<?php
+
+namespace Sabre\VObject\Component;
+
+use Sabre\VObject;
+
+/**
+ * The VTimeZone component.
+ *
+ * This component adds functionality to a component, specific for VTIMEZONE
+ * components.
+ *
+ * @copyright Copyright (C) fruux GmbH (https://fruux.com/)
+ * @author Evert Pot (http://evertpot.com/)
+ * @license http://sabre.io/license/ Modified BSD License
+ */
+class VTimeZone extends VObject\Component {
+
+    /**
+     * Returns the PHP DateTimeZone for this VTIMEZONE component.
+     *
+     * If we can't accurately determine the timezone, this method will return
+     * UTC.
+     *
+     * @return \DateTimeZone
+     */
+    function getTimeZone() {
+
+        return VObject\TimeZoneUtil::getTimeZone((string)$this->TZID, $this->root);
+
+    }
+
+    /**
+     * A simple list of validation rules.
+     *
+     * This is simply a list of properties, and how many times they either
+     * must or must not appear.
+     *
+     * Possible values per property:
+     *   * 0 - Must not appear.
+     *   * 1 - Must appear exactly once.
+     *   * + - Must appear at least once.
+     *   * * - Can appear any number of times.
+     *   * ? - May appear, but not more than once.
+     *
+     * @var array
+     */
+    function getValidationRules() {
+
+        return [
+            'TZID' => 1,
+
+            'LAST-MODIFIED' => '?',
+            'TZURL'         => '?',
+
+            // At least 1 STANDARD or DAYLIGHT must appear, or more. But both
+            // cannot appear in the same VTIMEZONE.
+            //
+            // The validator is not specific yet to pick this up, so these
+            // rules are too loose.
+            'STANDARD' => '*',
+            'DAYLIGHT' => '*',
+        ];
+
+    }
+
+}
diff --git a/vendor/sabre/vobject/lib/Component/VTodo.php b/vendor/sabre/vobject/lib/Component/VTodo.php
new file mode 100644
index 000000000..144ced694
--- /dev/null
+++ b/vendor/sabre/vobject/lib/Component/VTodo.php
@@ -0,0 +1,193 @@
+<?php
+
+namespace Sabre\VObject\Component;
+
+use DateTimeInterface;
+use Sabre\VObject;
+
+/**
+ * VTodo component.
+ *
+ * This component contains some additional functionality specific for VTODOs.
+ *
+ * @copyright Copyright (C) fruux GmbH (https://fruux.com/)
+ * @author Evert Pot (http://evertpot.com/)
+ * @license http://sabre.io/license/ Modified BSD License
+ */
+class VTodo extends VObject\Component {
+
+    /**
+     * Returns true or false depending on if the event falls in the specified
+     * time-range. This is used for filtering purposes.
+     *
+     * The rules used to determine if an event falls within the specified
+     * time-range is based on the CalDAV specification.
+     *
+     * @param DateTimeInterface $start
+     * @param DateTimeInterface $end
+     *
+     * @return bool
+     */
+    function isInTimeRange(DateTimeInterface $start, DateTimeInterface $end) {
+
+        $dtstart = isset($this->DTSTART) ? $this->DTSTART->getDateTime() : null;
+        $duration = isset($this->DURATION) ? VObject\DateTimeParser::parseDuration($this->DURATION) : null;
+        $due = isset($this->DUE) ? $this->DUE->getDateTime() : null;
+        $completed = isset($this->COMPLETED) ? $this->COMPLETED->getDateTime() : null;
+        $created = isset($this->CREATED) ? $this->CREATED->getDateTime() : null;
+
+        if ($dtstart) {
+            if ($duration) {
+                $effectiveEnd = $dtstart->add($duration);
+                return $start <= $effectiveEnd && $end > $dtstart;
+            } elseif ($due) {
+                return
+                    ($start < $due || $start <= $dtstart) &&
+                    ($end > $dtstart || $end >= $due);
+            } else {
+                return $start <= $dtstart && $end > $dtstart;
+            }
+        }
+        if ($due) {
+            return ($start < $due && $end >= $due);
+        }
+        if ($completed && $created) {
+            return
+                ($start <= $created || $start <= $completed) &&
+                ($end >= $created || $end >= $completed);
+        }
+        if ($completed) {
+            return ($start <= $completed && $end >= $completed);
+        }
+        if ($created) {
+            return ($end > $created);
+        }
+        return true;
+
+    }
+
+    /**
+     * A simple list of validation rules.
+     *
+     * This is simply a list of properties, and how many times they either
+     * must or must not appear.
+     *
+     * Possible values per property:
+     *   * 0 - Must not appear.
+     *   * 1 - Must appear exactly once.
+     *   * + - Must appear at least once.
+     *   * * - Can appear any number of times.
+     *   * ? - May appear, but not more than once.
+     *
+     * @var array
+     */
+    function getValidationRules() {
+
+        return [
+            'UID'     => 1,
+            'DTSTAMP' => 1,
+
+            'CLASS'         => '?',
+            'COMPLETED'     => '?',
+            'CREATED'       => '?',
+            'DESCRIPTION'   => '?',
+            'DTSTART'       => '?',
+            'GEO'           => '?',
+            'LAST-MODIFIED' => '?',
+            'LOCATION'      => '?',
+            'ORGANIZER'     => '?',
+            'PERCENT'       => '?',
+            'PRIORITY'      => '?',
+            'RECURRENCE-ID' => '?',
+            'SEQUENCE'      => '?',
+            'STATUS'        => '?',
+            'SUMMARY'       => '?',
+            'URL'           => '?',
+
+            'RRULE'    => '?',
+            'DUE'      => '?',
+            'DURATION' => '?',
+
+            'ATTACH'         => '*',
+            'ATTENDEE'       => '*',
+            'CATEGORIES'     => '*',
+            'COMMENT'        => '*',
+            'CONTACT'        => '*',
+            'EXDATE'         => '*',
+            'REQUEST-STATUS' => '*',
+            'RELATED-TO'     => '*',
+            'RESOURCES'      => '*',
+            'RDATE'          => '*',
+        ];
+
+    }
+
+    /**
+     * Validates the node for correctness.
+     *
+     * The following options are supported:
+     *   Node::REPAIR - May attempt to automatically repair the problem.
+     *
+     * This method returns an array with detected problems.
+     * Every element has the following properties:
+     *
+     *  * level - problem level.
+     *  * message - A human-readable string describing the issue.
+     *  * node - A reference to the problematic node.
+     *
+     * The level means:
+     *   1 - The issue was repaired (only happens if REPAIR was turned on)
+     *   2 - An inconsequential issue
+     *   3 - A severe issue.
+     *
+     * @param int $options
+     *
+     * @return array
+     */
+    function validate($options = 0) {
+
+        $result = parent::validate($options);
+        if (isset($this->DUE) && isset($this->DTSTART)) {
+
+            $due = $this->DUE;
+            $dtStart = $this->DTSTART;
+
+            if ($due->getValueType() !== $dtStart->getValueType()) {
+
+                $result[] = [
+                    'level'   => 3,
+                    'message' => 'The value type (DATE or DATE-TIME) must be identical for DUE and DTSTART',
+                    'node'    => $due,
+                ];
+
+            } elseif ($due->getDateTime() < $dtStart->getDateTime()) {
+
+                $result[] = [
+                    'level'   => 3,
+                    'message' => 'DUE must occur after DTSTART',
+                    'node'    => $due,
+                ];
+
+            }
+
+        }
+
+        return $result;
+
+    }
+
+    /**
+     * This method should return a list of default property values.
+     *
+     * @return array
+     */
+    protected function getDefaults() {
+
+        return [
+            'UID'     => 'sabre-vobject-' . VObject\UUIDUtil::getUUID(),
+            'DTSTAMP' => date('Ymd\\THis\\Z'),
+        ];
+
+    }
+
+}