[7589] | 1 | <?php |
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| 2 | /*********************************************** |
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| 3 | * File : diffstate.php |
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| 4 | * Project : Z-Push |
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| 5 | * Descr : This is the differential engine. |
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| 6 | * We do a standard differential |
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| 7 | * change detection by sorting both |
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| 8 | * lists of items by their unique id, |
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| 9 | * and then traversing both arrays |
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| 10 | * of items at once. Changes can be |
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| 11 | * detected by comparing items at |
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| 12 | * the same position in both arrays. |
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| 13 | * |
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| 14 | * Created : 02.01.2012 |
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| 15 | * |
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| 16 | * Copyright 2007 - 2012 Zarafa Deutschland GmbH |
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| 17 | * |
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| 18 | * This program is free software: you can redistribute it and/or modify |
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| 19 | * it under the terms of the GNU Affero General Public License, version 3, |
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| 20 | * as published by the Free Software Foundation with the following additional |
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| 21 | * term according to sec. 7: |
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| 22 | * |
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| 23 | * According to sec. 7 of the GNU Affero General Public License, version 3, |
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| 24 | * the terms of the AGPL are supplemented with the following terms: |
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| 25 | * |
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| 26 | * "Zarafa" is a registered trademark of Zarafa B.V. |
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| 27 | * "Z-Push" is a registered trademark of Zarafa Deutschland GmbH |
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| 28 | * The licensing of the Program under the AGPL does not imply a trademark license. |
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| 29 | * Therefore any rights, title and interest in our trademarks remain entirely with us. |
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| 30 | * |
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| 31 | * However, if you propagate an unmodified version of the Program you are |
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| 32 | * allowed to use the term "Z-Push" to indicate that you distribute the Program. |
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| 33 | * Furthermore you may use our trademarks where it is necessary to indicate |
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| 34 | * the intended purpose of a product or service provided you use it in accordance |
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| 35 | * with honest practices in industrial or commercial matters. |
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| 36 | * If you want to propagate modified versions of the Program under the name "Z-Push", |
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| 37 | * you may only do so if you have a written permission by Zarafa Deutschland GmbH |
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| 38 | * (to acquire a permission please contact Zarafa at trademark@zarafa.com). |
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| 39 | * |
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| 40 | * This program is distributed in the hope that it will be useful, |
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| 41 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
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| 42 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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| 43 | * GNU Affero General Public License for more details. |
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| 44 | * |
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| 45 | * You should have received a copy of the GNU Affero General Public License |
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| 46 | * along with this program. If not, see <http://www.gnu.org/licenses/>. |
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| 47 | * |
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| 48 | * Consult LICENSE file for details |
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| 49 | ************************************************/ |
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| 50 | |
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| 51 | class DiffState implements IChanges { |
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| 52 | protected $syncstate; |
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| 53 | protected $backend; |
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| 54 | protected $flags; |
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| 55 | |
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| 56 | /** |
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| 57 | * Initializes the state |
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| 58 | * |
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| 59 | * @param string $state |
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| 60 | * @param int $flags |
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| 61 | * |
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| 62 | * @access public |
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| 63 | * @return boolean status flag |
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| 64 | * @throws StatusException |
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| 65 | */ |
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| 66 | public function Config($state, $flags = 0) { |
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| 67 | if ($state == "") |
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| 68 | $state = array(); |
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| 69 | |
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| 70 | if (!is_array($state)) |
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| 71 | throw new StatusException("Invalid state", SYNC_FSSTATUS_CODEUNKNOWN); |
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| 72 | |
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| 73 | $this->syncstate = $state; |
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| 74 | $this->flags = $flags; |
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| 75 | return true; |
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| 76 | } |
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| 77 | |
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| 78 | /** |
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| 79 | * Returns state |
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| 80 | * |
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| 81 | * @access public |
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| 82 | * @return string |
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| 83 | * @throws StatusException |
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| 84 | */ |
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| 85 | public function GetState() { |
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| 86 | if (!isset($this->syncstate) || !is_array($this->syncstate)) |
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| 87 | throw new StatusException("DiffState->GetState(): Error, state not available", SYNC_FSSTATUS_CODEUNKNOWN, null, LOGLEVEL_WARN); |
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| 88 | |
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| 89 | return $this->syncstate; |
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| 90 | } |
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| 91 | |
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| 92 | |
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| 93 | /**---------------------------------------------------------------------------------------------------------- |
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| 94 | * DiffState specific stuff |
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| 95 | */ |
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| 96 | |
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| 97 | /** |
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| 98 | * Comparing function used for sorting of the differential engine |
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| 99 | * |
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| 100 | * @param array $a |
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| 101 | * @param array $b |
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| 102 | * |
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| 103 | * @access public |
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| 104 | * @return boolean |
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| 105 | */ |
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| 106 | static public function RowCmp($a, $b) { |
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| 107 | // TODO implement different comparing functions |
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| 108 | return $a["id"] < $b["id"] ? 1 : -1; |
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| 109 | } |
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| 110 | |
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| 111 | /** |
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| 112 | * Differential mechanism |
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| 113 | * Compares the current syncstate to the sent $new |
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| 114 | * |
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| 115 | * @param array $new |
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| 116 | * |
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| 117 | * @access protected |
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| 118 | * @return array |
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| 119 | */ |
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| 120 | protected function getDiffTo($new) { |
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| 121 | $changes = array(); |
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| 122 | |
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| 123 | // Sort both arrays in the same way by ID |
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| 124 | usort($this->syncstate, array("DiffState", "RowCmp")); |
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| 125 | usort($new, array("DiffState", "RowCmp")); |
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| 126 | |
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| 127 | $inew = 0; |
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| 128 | $iold = 0; |
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| 129 | |
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| 130 | // Get changes by comparing our list of messages with |
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| 131 | // our previous state |
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| 132 | while(1) { |
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| 133 | $change = array(); |
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| 134 | |
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| 135 | if($iold >= count($this->syncstate) || $inew >= count($new)) |
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| 136 | break; |
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| 137 | |
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| 138 | if($this->syncstate[$iold]["id"] == $new[$inew]["id"]) { |
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| 139 | // Both messages are still available, compare flags and mod |
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| 140 | if(isset($this->syncstate[$iold]["flags"]) && isset($new[$inew]["flags"]) && $this->syncstate[$iold]["flags"] != $new[$inew]["flags"]) { |
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| 141 | // Flags changed |
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| 142 | $change["type"] = "flags"; |
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| 143 | $change["id"] = $new[$inew]["id"]; |
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| 144 | $change["flags"] = $new[$inew]["flags"]; |
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| 145 | $changes[] = $change; |
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| 146 | } |
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| 147 | |
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| 148 | if($this->syncstate[$iold]["mod"] != $new[$inew]["mod"]) { |
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| 149 | $change["type"] = "change"; |
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| 150 | $change["id"] = $new[$inew]["id"]; |
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| 151 | $changes[] = $change; |
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| 152 | } |
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| 153 | |
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| 154 | $inew++; |
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| 155 | $iold++; |
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| 156 | } else { |
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| 157 | if($this->syncstate[$iold]["id"] > $new[$inew]["id"]) { |
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| 158 | // Message in state seems to have disappeared (delete) |
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| 159 | $change["type"] = "delete"; |
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| 160 | $change["id"] = $this->syncstate[$iold]["id"]; |
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| 161 | $changes[] = $change; |
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| 162 | $iold++; |
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| 163 | } else { |
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| 164 | // Message in new seems to be new (add) |
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| 165 | $change["type"] = "change"; |
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| 166 | $change["flags"] = SYNC_NEWMESSAGE; |
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| 167 | $change["id"] = $new[$inew]["id"]; |
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| 168 | $changes[] = $change; |
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| 169 | $inew++; |
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| 170 | } |
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| 171 | } |
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| 172 | } |
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| 173 | |
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| 174 | while($iold < count($this->syncstate)) { |
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| 175 | // All data left in 'syncstate' have been deleted |
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| 176 | $change["type"] = "delete"; |
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| 177 | $change["id"] = $this->syncstate[$iold]["id"]; |
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| 178 | $changes[] = $change; |
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| 179 | $iold++; |
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| 180 | } |
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| 181 | |
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| 182 | while($inew < count($new)) { |
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| 183 | // All data left in new have been added |
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| 184 | $change["type"] = "change"; |
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| 185 | $change["flags"] = SYNC_NEWMESSAGE; |
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| 186 | $change["id"] = $new[$inew]["id"]; |
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| 187 | $changes[] = $change; |
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| 188 | $inew++; |
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| 189 | } |
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| 190 | |
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| 191 | return $changes; |
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| 192 | } |
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| 193 | |
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| 194 | /** |
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| 195 | * Update the state to reflect changes |
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| 196 | * |
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| 197 | * @param string $type of change |
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| 198 | * @param array $change |
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| 199 | * |
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| 200 | * |
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| 201 | * @access protected |
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| 202 | * @return |
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| 203 | */ |
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| 204 | protected function updateState($type, $change) { |
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| 205 | // Change can be a change or an add |
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| 206 | if($type == "change") { |
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| 207 | for($i=0; $i < count($this->syncstate); $i++) { |
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| 208 | if($this->syncstate[$i]["id"] == $change["id"]) { |
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| 209 | $this->syncstate[$i] = $change; |
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| 210 | return; |
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| 211 | } |
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| 212 | } |
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| 213 | // Not found, add as new |
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| 214 | $this->syncstate[] = $change; |
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| 215 | } else { |
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| 216 | for($i=0; $i < count($this->syncstate); $i++) { |
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| 217 | // Search for the entry for this item |
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| 218 | if($this->syncstate[$i]["id"] == $change["id"]) { |
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| 219 | if($type == "flags") { |
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| 220 | // Update flags |
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| 221 | $this->syncstate[$i]["flags"] = $change["flags"]; |
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| 222 | } else if($type == "delete") { |
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| 223 | // Delete item |
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| 224 | array_splice($this->syncstate, $i, 1); |
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| 225 | } |
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| 226 | return; |
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| 227 | } |
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| 228 | } |
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| 229 | } |
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| 230 | } |
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| 231 | |
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| 232 | /** |
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| 233 | * Returns TRUE if the given ID conflicts with the given operation. This is only true in the following situations: |
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| 234 | * - Changed here and changed there |
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| 235 | * - Changed here and deleted there |
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| 236 | * - Deleted here and changed there |
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| 237 | * Any other combination of operations can be done (e.g. change flags & move or move & delete) |
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| 238 | * |
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| 239 | * @param string $type of change |
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| 240 | * @param string $folderid |
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| 241 | * @param string $id |
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| 242 | * |
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| 243 | * @access protected |
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| 244 | * @return |
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| 245 | */ |
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| 246 | protected function isConflict($type, $folderid, $id) { |
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| 247 | $stat = $this->backend->StatMessage($folderid, $id); |
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| 248 | |
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| 249 | if(!$stat) { |
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| 250 | // Message is gone |
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| 251 | if($type == "change") |
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| 252 | return true; // deleted here, but changed there |
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| 253 | else |
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| 254 | return false; // all other remote changes still result in a delete (no conflict) |
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| 255 | } |
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| 256 | |
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| 257 | foreach($this->syncstate as $state) { |
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| 258 | if($state["id"] == $id) { |
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| 259 | $oldstat = $state; |
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| 260 | break; |
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| 261 | } |
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| 262 | } |
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| 263 | |
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| 264 | if(!isset($oldstat)) { |
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| 265 | // New message, can never conflict |
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| 266 | return false; |
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| 267 | } |
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| 268 | |
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| 269 | if($stat["mod"] != $oldstat["mod"]) { |
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| 270 | // Changed here |
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| 271 | if($type == "delete" || $type == "change") |
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| 272 | return true; // changed here, but deleted there -> conflict, or changed here and changed there -> conflict |
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| 273 | else |
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| 274 | return false; // changed here, and other remote changes (move or flags) |
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| 275 | } |
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| 276 | } |
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| 277 | |
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| 278 | } |
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| 279 | |
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| 280 | ?> |
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