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+<?php
+
+/*
+ +-----------------------------------------------------------------------+
+ | program/include/rcube_imap_cache.php |
+ | |
+ | This file is part of the Roundcube Webmail client |
+ | Copyright (C) 2005-2011, The Roundcube Dev Team |
+ | Licensed under the GNU GPL |
+ | |
+ | PURPOSE: |
+ | Caching of IMAP folder contents (messages and index) |
+ | |
+ +-----------------------------------------------------------------------+
+ | Author: Thomas Bruederli <roundcube@gmail.com> |
+ | Author: Aleksander Machniak <alec@alec.pl> |
+ +-----------------------------------------------------------------------+
+
+ $Id$
+
+*/
+
+
+/**
+ * Interface class for accessing Roundcube messages cache
+ *
+ * @package Cache
+ * @author Thomas Bruederli <roundcube@gmail.com>
+ * @author Aleksander Machniak <alec@alec.pl>
+ * @version 1.0
+ */
+class rcube_imap_cache
+{
+ /**
+ * Instance of rcube_imap
+ *
+ * @var rcube_imap
+ */
+ private $imap;
+
+ /**
+ * Instance of rcube_mdb2
+ *
+ * @var rcube_mdb2
+ */
+ private $db;
+
+ /**
+ * User ID
+ *
+ * @var int
+ */
+ private $userid;
+
+ /**
+ * Internal (in-memory) cache
+ *
+ * @var array
+ */
+ private $icache = array();
+
+ private $skip_deleted = false;
+
+ public $flag_fields = array('seen', 'deleted', 'answered', 'forwarded', 'flagged', 'mdnsent');
+
+
+ /**
+ * Object constructor.
+ */
+ function __construct($db, $imap, $userid, $skip_deleted)
+ {
+ $this->db = $db;
+ $this->imap = $imap;
+ $this->userid = (int)$userid;
+ $this->skip_deleted = $skip_deleted;
+ }
+
+
+ /**
+ * Cleanup actions (on shutdown).
+ */
+ public function close()
+ {
+ $this->save_icache();
+ $this->icache = null;
+ }
+
+
+ /**
+ * Return (sorted) messages index.
+ * If index doesn't exist or is invalid, will be updated.
+ *
+ * @param string $mailbox Folder name
+ * @param string $sort_field Sorting column
+ * @param string $sort_order Sorting order (ASC|DESC)
+ * @param bool $exiting Skip index initialization if it doesn't exist in DB
+ *
+ * @return array Messages index
+ */
+ function get_index($mailbox, $sort_field = null, $sort_order = null, $existing = false)
+ {
+ if (empty($this->icache[$mailbox]))
+ $this->icache[$mailbox] = array();
+
+ $sort_order = strtoupper($sort_order) == 'ASC' ? 'ASC' : 'DESC';
+
+ // Seek in internal cache
+ if (array_key_exists('index', $this->icache[$mailbox])
+ && ($sort_field == 'ANY' || $this->icache[$mailbox]['index']['sort_field'] == $sort_field)
+ ) {
+ if ($this->icache[$mailbox]['index']['sort_order'] == $sort_order)
+ return $this->icache[$mailbox]['index']['result'];
+ else
+ return array_reverse($this->icache[$mailbox]['index']['result'], true);
+ }
+
+ // Get index from DB (if DB wasn't already queried)
+ if (empty($this->icache[$mailbox]['index_queried'])) {
+ $index = $this->get_index_row($mailbox);
+
+ // set the flag that DB was already queried for index
+ // this way we'll be able to skip one SELECT, when
+ // get_index() is called more than once
+ $this->icache[$mailbox]['index_queried'] = true;
+ }
+ $data = null;
+
+ // @TODO: Think about skipping validation checks.
+ // If we could check only every 10 minutes, we would be able to skip
+ // expensive checks, mailbox selection or even IMAP connection, this would require
+ // additional logic to force cache invalidation in some cases
+ // and many rcube_imap changes to connect when needed
+
+ // Entry exist, check cache status
+ if (!empty($index)) {
+ $exists = true;
+
+ if ($sort_field == 'ANY') {
+ $sort_field = $index['sort_field'];
+ }
+
+ if ($sort_field != $index['sort_field']) {
+ $is_valid = false;
+ }
+ else {
+ $is_valid = $this->validate($mailbox, $index, $exists);
+ }
+
+ if ($is_valid) {
+ // build index, assign sequence IDs to unique IDs
+ $data = array_combine($index['seq'], $index['uid']);
+ // revert the order if needed
+ if ($index['sort_order'] != $sort_order)
+ $data = array_reverse($data, true);
+ }
+ }
+ else {
+ // Got it in internal cache, so the row already exist
+ $exists = array_key_exists('index', $this->icache[$mailbox]);
+
+ if ($existing) {
+ return null;
+ }
+ else if ($sort_field == 'ANY') {
+ $sort_field = '';
+ }
+ }
+
+ // Index not found, not valid or sort field changed, get index from IMAP server
+ if ($data === null) {
+ // Get mailbox data (UIDVALIDITY, counters, etc.) for status check
+ $mbox_data = $this->imap->mailbox_data($mailbox);
+ $data = array();
+
+ // Prevent infinite loop.
+ // It happens when rcube_imap::message_index_direct() is called.
+ // There id2uid() is called which will again call get_index() and so on.
+ if (!$sort_field && !$this->skip_deleted)
+ $this->icache['pending_index_update'] = true;
+
+ if ($mbox_data['EXISTS']) {
+ // fetch sorted sequence numbers
+ $data_seq = $this->imap->message_index_direct($mailbox, $sort_field, $sort_order);
+ // fetch UIDs
+ if (!empty($data_seq)) {
+ // Seek in internal cache
+ if (array_key_exists('index', (array)$this->icache[$mailbox]))
+ $data_uid = $this->icache[$mailbox]['index']['result'];
+ else
+ $data_uid = $this->imap->conn->fetchUIDs($mailbox, $data_seq);
+
+ // build index
+ if (!empty($data_uid)) {
+ foreach ($data_seq as $seq)
+ if ($uid = $data_uid[$seq])
+ $data[$seq] = $uid;
+ }
+ }
+ }
+
+ // Reset internal flags
+ $this->icache['pending_index_update'] = false;
+
+ // insert/update
+ $this->add_index_row($mailbox, $sort_field, $sort_order, $data, $mbox_data, $exists);
+ }
+
+ $this->icache[$mailbox]['index'] = array(
+ 'result' => $data,
+ 'sort_field' => $sort_field,
+ 'sort_order' => $sort_order,
+ );
+
+ return $data;
+ }
+
+
+ /**
+ * Return messages thread.
+ * If threaded index doesn't exist or is invalid, will be updated.
+ *
+ * @param string $mailbox Folder name
+ * @param string $sort_field Sorting column
+ * @param string $sort_order Sorting order (ASC|DESC)
+ *
+ * @return array Messages threaded index
+ */
+ function get_thread($mailbox)
+ {
+ if (empty($this->icache[$mailbox]))
+ $this->icache[$mailbox] = array();
+
+ // Seek in internal cache
+ if (array_key_exists('thread', $this->icache[$mailbox])) {
+ return array(
+ $this->icache[$mailbox]['thread']['tree'],
+ $this->icache[$mailbox]['thread']['depth'],
+ $this->icache[$mailbox]['thread']['children'],
+ );
+ }
+
+ // Get index from DB
+ $index = $this->get_thread_row($mailbox);
+ $data = null;
+
+ // Entry exist, check cache status
+ if (!empty($index)) {
+ $exists = true;
+ $is_valid = $this->validate($mailbox, $index, $exists);
+
+ if (!$is_valid) {
+ $index = null;
+ }
+ }
+
+ // Index not found or not valid, get index from IMAP server
+ if ($index === null) {
+ // Get mailbox data (UIDVALIDITY, counters, etc.) for status check
+ $mbox_data = $this->imap->mailbox_data($mailbox);
+
+ if ($mbox_data['EXISTS']) {
+ // get all threads (default sort order)
+ list ($thread_tree, $msg_depth, $has_children) = $this->imap->fetch_threads($mailbox, true);
+ }
+
+ $index = array(
+ 'tree' => !empty($thread_tree) ? $thread_tree : array(),
+ 'depth' => !empty($msg_depth) ? $msg_depth : array(),
+ 'children' => !empty($has_children) ? $has_children : array(),
+ );
+
+ // insert/update
+ $this->add_thread_row($mailbox, $index, $mbox_data, $exists);
+ }
+
+ $this->icache[$mailbox]['thread'] = $index;
+
+ return array($index['tree'], $index['depth'], $index['children']);
+ }
+
+
+ /**
+ * Returns list of messages (headers). See rcube_imap::fetch_headers().
+ *
+ * @param string $mailbox Folder name
+ * @param array $msgs Message sequence numbers
+ * @param bool $is_uid True if $msgs contains message UIDs
+ *
+ * @return array The list of messages (rcube_mail_header) indexed by UID
+ */
+ function get_messages($mailbox, $msgs = array(), $is_uid = true)
+ {
+ if (empty($msgs)) {
+ return array();
+ }
+
+ // Convert IDs to UIDs
+ // @TODO: it would be nice if we could work with UIDs only
+ // then, e.g. when fetching search result, index would be not needed
+ if (!$is_uid) {
+ $index = $this->get_index($mailbox, 'ANY');
+ foreach ($msgs as $idx => $msgid)
+ if ($uid = $index[$msgid])
+ $msgs[$idx] = $uid;
+ }
+
+ $flag_fields = implode(', ', array_map(array($this->db, 'quoteIdentifier'), $this->flag_fields));
+
+ // Fetch messages from cache
+ $sql_result = $this->db->query(
+ "SELECT uid, data, ".$flag_fields
+ ." FROM ".get_table_name('cache_messages')
+ ." WHERE user_id = ?"
+ ." AND mailbox = ?"
+ ." AND uid IN (".$this->db->array2list($msgs, 'integer').")",
+ $this->userid, $mailbox);
+
+ $msgs = array_flip($msgs);
+ $result = array();
+
+ while ($sql_arr = $this->db->fetch_assoc($sql_result)) {
+ $uid = intval($sql_arr['uid']);
+ $result[$uid] = $this->build_message($sql_arr);
+ // save memory, we don't need a body here
+ $result[$uid]->body = null;
+//@TODO: update message ID according to index data?
+
+ if (!empty($result[$uid])) {
+ unset($msgs[$uid]);
+ }
+ }
+
+ // Fetch not found messages from IMAP server
+ if (!empty($msgs)) {
+ $messages = $this->imap->fetch_headers($mailbox, array_keys($msgs), true, true);
+
+ // Insert to DB and add to result list
+ if (!empty($messages)) {
+ foreach ($messages as $msg) {
+ $this->add_message($mailbox, $msg, !array_key_exists($msg->uid, $result));
+ $result[$msg->uid] = $msg;
+ }
+ }
+ }
+
+ return $result;
+ }
+
+
+ /**
+ * Returns message data.
+ *
+ * @param string $mailbox Folder name
+ * @param int $uid Message UID
+ *
+ * @return rcube_mail_header Message data
+ */
+ function get_message($mailbox, $uid)
+ {
+ // Check internal cache
+ if (($message = $this->icache['message'])
+ && $message['mailbox'] == $mailbox && $message['object']->uid == $uid
+ ) {
+ return $this->icache['message']['object'];
+ }
+
+ $flag_fields = implode(', ', array_map(array($this->db, 'quoteIdentifier'), $this->flag_fields));
+
+ $sql_result = $this->db->query(
+ "SELECT data, ".$flag_fields
+ ." FROM ".get_table_name('cache_messages')
+ ." WHERE user_id = ?"
+ ." AND mailbox = ?"
+ ." AND uid = ?",
+ $this->userid, $mailbox, (int)$uid);
+
+ if ($sql_arr = $this->db->fetch_assoc($sql_result)) {
+ $message = $this->build_message($sql_arr);
+ $found = true;
+
+//@TODO: update message ID according to index data?
+ }
+
+ // Get the message from IMAP server
+ if (empty($message)) {
+ $message = $this->imap->get_headers($uid, $mailbox, true);
+ // cache will be updated in close(), see below
+ }
+
+ // Save the message in internal cache, will be written to DB in close()
+ // Common scenario: user opens unseen message
+ // - get message (SELECT)
+ // - set message headers/structure (INSERT or UPDATE)
+ // - set \Seen flag (UPDATE)
+ // This way we can skip one UPDATE
+ if (!empty($message)) {
+ // Save current message from internal cache
+ $this->save_icache();
+
+ $this->icache['message'] = array(
+ 'object' => $message,
+ 'mailbox' => $mailbox,
+ 'exists' => $found,
+ 'md5sum' => md5(serialize($message)),
+ );
+ }
+
+ return $message;
+ }
+
+
+ /**
+ * Saves the message in cache.
+ *
+ * @param string $mailbox Folder name
+ * @param rcube_mail_header $message Message data
+ * @param bool $force Skips message in-cache existance check
+ */
+ function add_message($mailbox, $message, $force = false)
+ {
+ if (!is_object($message) || empty($message->uid))
+ return;
+
+ $msg = serialize($this->db->encode(clone $message));
+
+ $flag_fields = array_map(array($this->db, 'quoteIdentifier'), $this->flag_fields);
+ $flag_values = array();
+
+ foreach ($this->flag_fields as $flag)
+ $flag_values[] = (int) $message->$flag;
+
+ // update cache record (even if it exists, the update
+ // here will work as select, assume row exist if affected_rows=0)
+ if (!$force) {
+ foreach ($flag_fields as $key => $val)
+ $flag_data[] = $val . " = " . $flag_values[$key];
+
+ $res = $this->db->query(
+ "UPDATE ".get_table_name('cache_messages')
+ ." SET data = ?, changed = ".$this->db->now()
+ .", " . implode(', ', $flag_data)
+ ." WHERE user_id = ?"
+ ." AND mailbox = ?"
+ ." AND uid = ?",
+ $msg, $this->userid, $mailbox, (int) $message->uid);
+
+ if ($this->db->affected_rows())
+ return;
+ }
+
+ // insert new record
+ $this->db->query(
+ "INSERT INTO ".get_table_name('cache_messages')
+ ." (user_id, mailbox, uid, changed, data, " . implode(', ', $flag_fields) . ")"
+ ." VALUES (?, ?, ?, ".$this->db->now().", ?, " . implode(', ', $flag_values) . ")",
+ $this->userid, $mailbox, (int) $message->uid, $msg);
+ }
+
+
+ /**
+ * Sets the flag for specified message.
+ *
+ * @param string $mailbox Folder name
+ * @param array $uids Message UIDs or null to change flag
+ * of all messages in a folder
+ * @param string $flag The name of the flag
+ * @param bool $enabled Flag state
+ */
+ function change_flag($mailbox, $uids, $flag, $enabled = false)
+ {
+ $flag = strtolower($flag);
+
+ if (in_array($flag, $this->flag_fields)) {
+ // Internal cache update
+ if ($uids && count($uids) == 1 && ($uid = current($uids))
+ && ($message = $this->icache['message'])
+ && $message['mailbox'] == $mailbox && $message['object']->uid == $uid
+ ) {
+ $message['object']->$flag = $enabled;
+ return;
+ }
+
+ $this->db->query(
+ "UPDATE ".get_table_name('cache_messages')
+ ." SET changed = ".$this->db->now()
+ .", " .$this->db->quoteIdentifier($flag) . " = " . intval($enabled)
+ ." WHERE user_id = ?"
+ ." AND mailbox = ?"
+ .($uids !== null ? " AND uid IN (".$this->db->array2list((array)$uids, 'integer').")" : ""),
+ $this->userid, $mailbox);
+ }
+ else {
+ // @TODO: SELECT+UPDATE?
+ $this->remove_message($mailbox, $uids);
+ }
+ }
+
+
+ /**
+ * Removes message(s) from cache.
+ *
+ * @param string $mailbox Folder name
+ * @param array $uids Message UIDs, NULL removes all messages
+ */
+ function remove_message($mailbox = null, $uids = null)
+ {
+ if (!strlen($mailbox)) {
+ $this->db->query(
+ "DELETE FROM ".get_table_name('cache_messages')
+ ." WHERE user_id = ?",
+ $this->userid);
+ }
+ else {
+ // Remove the message from internal cache
+ if (!empty($uids) && !is_array($uids) && ($message = $this->icache['message'])
+ && $message['mailbox'] == $mailbox && $message['object']->uid == $uids
+ ) {
+ $this->icache['message'] = null;
+ }
+
+ $this->db->query(
+ "DELETE FROM ".get_table_name('cache_messages')
+ ." WHERE user_id = ?"
+ ." AND mailbox = ".$this->db->quote($mailbox)
+ .($uids !== null ? " AND uid IN (".$this->db->array2list((array)$uids, 'integer').")" : ""),
+ $this->userid);
+ }
+
+ }
+
+
+ /**
+ * Clears index cache.
+ *
+ * @param string $mailbox Folder name
+ */
+ function remove_index($mailbox = null)
+ {
+ $this->db->query(
+ "DELETE FROM ".get_table_name('cache_index')
+ ." WHERE user_id = ".intval($this->userid)
+ .(strlen($mailbox) ? " AND mailbox = ".$this->db->quote($mailbox) : "")
+ );
+
+ if (strlen($mailbox))
+ unset($this->icache[$mailbox]['index']);
+ else
+ $this->icache = array();
+ }
+
+
+ /**
+ * Clears thread cache.
+ *
+ * @param string $mailbox Folder name
+ */
+ function remove_thread($mailbox = null)
+ {
+ $this->db->query(
+ "DELETE FROM ".get_table_name('cache_thread')
+ ." WHERE user_id = ".intval($this->userid)
+ .(strlen($mailbox) ? " AND mailbox = ".$this->db->quote($mailbox) : "")
+ );
+
+ if (strlen($mailbox))
+ unset($this->icache[$mailbox]['thread']);
+ else
+ $this->icache = array();
+ }
+
+
+ /**
+ * Clears the cache.
+ *
+ * @param string $mailbox Folder name
+ * @param array $uids Message UIDs, NULL removes all messages in a folder
+ */
+ function clear($mailbox = null, $uids = null)
+ {
+ $this->remove_index($mailbox);
+ $this->remove_thread($mailbox);
+ $this->remove_message($mailbox, $uids);
+ }
+
+
+ /**
+ * @param string $mailbox Folder name
+ * @param int $id Message (sequence) ID
+ *
+ * @return int Message UID
+ */
+ function id2uid($mailbox, $id)
+ {
+ if (!empty($this->icache['pending_index_update']))
+ return null;
+
+ // get index if it exists
+ $index = $this->get_index($mailbox, 'ANY', null, true);
+
+ return $index[$id];
+ }
+
+
+ /**
+ * @param string $mailbox Folder name
+ * @param int $uid Message UID
+ *
+ * @return int Message (sequence) ID
+ */
+ function uid2id($mailbox, $uid)
+ {
+ if (!empty($this->icache['pending_index_update']))
+ return null;
+
+ // get index if it exists
+ $index = $this->get_index($mailbox, 'ANY', null, true);
+
+ return array_search($uid, (array)$index);
+ }
+
+
+ /**
+ * Fetches index data from database
+ */
+ private function get_index_row($mailbox)
+ {
+ // Get index from DB
+ $sql_result = $this->db->query(
+ "SELECT data"
+ ." FROM ".get_table_name('cache_index')
+ ." WHERE user_id = ?"
+ ." AND mailbox = ?",
+ $this->userid, $mailbox);
+
+ if ($sql_arr = $this->db->fetch_assoc($sql_result)) {
+ $data = explode('@', $sql_arr['data']);
+
+ return array(
+ 'seq' => explode(',', $data[0]),
+ 'uid' => explode(',', $data[1]),
+ 'sort_field' => $data[2],
+ 'sort_order' => $data[3],
+ 'deleted' => $data[4],
+ 'validity' => $data[5],
+ 'uidnext' => $data[6],
+ );
+ }
+
+ return null;
+ }
+
+
+ /**
+ * Fetches thread data from database
+ */
+ private function get_thread_row($mailbox)
+ {
+ // Get thread from DB
+ $sql_result = $this->db->query(
+ "SELECT data"
+ ." FROM ".get_table_name('cache_thread')
+ ." WHERE user_id = ?"
+ ." AND mailbox = ?",
+ $this->userid, $mailbox);
+
+ if ($sql_arr = $this->db->fetch_assoc($sql_result)) {
+ $data = explode('@', $sql_arr['data']);
+
+ $data[0] = unserialize($data[0]);
+ // build 'depth' and 'children' arrays
+ $depth = $children = array();
+ $this->build_thread_data($data[0], $depth, $children);
+
+ return array(
+ 'tree' => $data[0],
+ 'depth' => $depth,
+ 'children' => $children,
+ 'deleted' => $data[1],
+ 'validity' => $data[2],
+ 'uidnext' => $data[3],
+ );
+ }
+
+ return null;
+ }
+
+
+ /**
+ * Saves index data into database
+ */
+ private function add_index_row($mailbox, $sort_field, $sort_order,
+ $data = array(), $mbox_data = array(), $exists = false)
+ {
+ $data = array(
+ implode(',', array_keys($data)),
+ implode(',', array_values($data)),
+ $sort_field,
+ $sort_order,
+ (int) $this->skip_deleted,
+ (int) $mbox_data['UIDVALIDITY'],
+ (int) $mbox_data['UIDNEXT'],
+ );
+ $data = implode('@', $data);
+
+ if ($exists)
+ $sql_result = $this->db->query(
+ "UPDATE ".get_table_name('cache_index')
+ ." SET data = ?, changed = ".$this->db->now()
+ ." WHERE user_id = ?"
+ ." AND mailbox = ?",
+ $data, $this->userid, $mailbox);
+ else
+ $sql_result = $this->db->query(
+ "INSERT INTO ".get_table_name('cache_index')
+ ." (user_id, mailbox, data, changed)"
+ ." VALUES (?, ?, ?, ".$this->db->now().")",
+ $this->userid, $mailbox, $data);
+ }
+
+
+ /**
+ * Saves thread data into database
+ */
+ private function add_thread_row($mailbox, $data = array(), $mbox_data = array(), $exists = false)
+ {
+ $data = array(
+ serialize($data['tree']),
+ (int) $this->skip_deleted,
+ (int) $mbox_data['UIDVALIDITY'],
+ (int) $mbox_data['UIDNEXT'],
+ );
+ $data = implode('@', $data);
+
+ if ($exists)
+ $sql_result = $this->db->query(
+ "UPDATE ".get_table_name('cache_thread')
+ ." SET data = ?, changed = ".$this->db->now()
+ ." WHERE user_id = ?"
+ ." AND mailbox = ?",
+ $data, $this->userid, $mailbox);
+ else
+ $sql_result = $this->db->query(
+ "INSERT INTO ".get_table_name('cache_thread')
+ ." (user_id, mailbox, data, changed)"
+ ." VALUES (?, ?, ?, ".$this->db->now().")",
+ $this->userid, $mailbox, $data);
+ }
+
+
+ /**
+ * Checks index/thread validity
+ */
+ private function validate($mailbox, $index, &$exists = true)
+ {
+ $is_thread = isset($index['tree']);
+
+ // Get mailbox data (UIDVALIDITY, counters, etc.) for status check
+ $mbox_data = $this->imap->mailbox_data($mailbox);
+
+ // @TODO: Think about skipping validation checks.
+ // If we could check only every 10 minutes, we would be able to skip
+ // expensive checks, mailbox selection or even IMAP connection, this would require
+ // additional logic to force cache invalidation in some cases
+ // and many rcube_imap changes to connect when needed
+
+ // Check UIDVALIDITY
+ // @TODO: while we're storing message sequence numbers in thread
+ // index, should UIDVALIDITY invalidate the thread data?
+ if ($index['validity'] != $mbox_data['UIDVALIDITY']) {
+ // the whole cache (all folders) is invalid
+ $this->clear();
+ $exists = false;
+ return false;
+ }
+
+ // Folder is empty but cache isn't
+ if (empty($mbox_data['EXISTS']) && (!empty($index['seq']) || !empty($index['tree']))) {
+ $this->clear($mailbox);
+ $exists = false;
+ return false;
+ }
+
+ // Check UIDNEXT
+ if ($index['uidnext'] != $mbox_data['UIDNEXT']) {
+ unset($this->icache[$mailbox][$is_thread ? 'thread' : 'index']);
+ return false;
+ }
+
+ // Index was created with different skip_deleted setting
+ if ($this->skip_deleted != $index['deleted']) {
+ return false;
+ }
+
+ // @TODO: find better validity check for threaded index
+ if ($is_thread) {
+ // check messages number...
+ if ($mbox_data['EXISTS'] != max(array_keys($index['depth']))) {
+ return false;
+ }
+ return true;
+ }
+
+ // The rest of checks, more expensive
+ if (!empty($this->skip_deleted)) {
+ // compare counts if available
+ if ($mbox_data['COUNT_UNDELETED'] != null
+ && $mbox_data['COUNT_UNDELETED'] != count($index['uid'])) {
+ return false;
+ }
+ // compare UID sets
+ if ($mbox_data['ALL_UNDELETED'] != null) {
+ $uids_new = rcube_imap_generic::uncompressMessageSet($mbox_data['ALL_UNDELETED']);
+ $uids_old = $index['uid'];
+
+ if (count($uids_new) != count($uids_old)) {
+ return false;
+ }
+
+ sort($uids_new, SORT_NUMERIC);
+ sort($uids_old, SORT_NUMERIC);
+
+ if ($uids_old != $uids_new)
+ return false;
+ }
+ else {
+ // get all undeleted messages excluding cached UIDs
+ $ids = $this->imap->search_once($mailbox, 'ALL UNDELETED NOT UID '.
+ rcube_imap_generic::compressMessageSet($index['uid']));
+
+ if (!empty($ids)) {
+ $index = null; // cache invalid
+ }
+ }
+ }
+ else {
+ // check messages number...
+ if ($mbox_data['EXISTS'] != max($index['seq'])) {
+ return false;
+ }
+ // ... and max UID
+ if (max($index['uid']) != $this->imap->id2uid($mbox_data['EXISTS'], $mailbox, true)) {
+ return false;
+ }
+ }
+
+ return true;
+ }
+
+
+ /**
+ * Converts cache row into message object.
+ *
+ * @param array $sql_arr Message row data
+ *
+ * @return rcube_mail_header Message object
+ */
+ private function build_message($sql_arr)
+ {
+ $message = $this->db->decode(unserialize($sql_arr['data']));
+
+ if ($message) {
+ foreach ($this->flag_fields as $field)
+ $message->$field = (bool) $sql_arr[$field];
+ }
+
+ return $message;
+ }
+
+
+ /**
+ * Creates 'depth' and 'children' arrays from stored thread 'tree' data.
+ */
+ private function build_thread_data($data, &$depth, &$children, $level = 0)
+ {
+ foreach ((array)$data as $key => $val) {
+ $children[$key] = !empty($val);
+ $depth[$key] = $level;
+ if (!empty($val))
+ $this->build_thread_data($val, $depth, $children, $level + 1);
+ }
+ }
+
+
+ /**
+ * Saves message stored in internal cache
+ */
+ private function save_icache()
+ {
+ // Save current message from internal cache
+ if ($message = $this->icache['message']) {
+ $object = $message['object'];
+ // remove body too big (>500kB)
+ if ($object->body && strlen($object->body) > 500 * 1024)
+ $object->body = null;
+
+ // calculate current md5 sum
+ $md5sum = md5(serialize($object));
+
+ if ($message['md5sum'] != $md5sum) {
+ $this->add_message($message['mailbox'], $object, !$message['exists']);
+ }
+
+ $this->icache['message']['md5sum'] = $md5sum;
+ }
+ }
+
+}