MDL-60357 core_search: Future modified times cause serious problems

2017-10-06 13:38:32 +01:00
parent d8e9a23c48
commit 2d2fcc1c9e
3 changed files with 149 additions and 1 deletions
@@ -0,0 +1,94 @@
+<?php
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+
+/**
+ * Iterator for skipping search recordset documents that are in the future.
+ *
+ * @package core_search
+ * @copyright 2017 The Open University
+ * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+namespace core_search;
+
+defined('MOODLE_INTERNAL') || die();
+
+/**
+ * Iterator for skipping search recordset documents that are in the future.
+ *
+ * This iterator stops iterating if it receives a document that was modified later than the
+ * specified cut-off time (usually current time).
+ *
+ * This iterator assumes that its parent iterator returns documents in modified order (which is
+ * required to be the case for search indexing). This means we will stop retrieving data from the
+ * recordset
+ *
+ * @copyright 2017 The Open University
+ * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class skip_future_documents_iterator implements \Iterator {
+    /** @var \Iterator Parent iterator */
+    protected $parent;
+
+    /** @var int Cutoff time; anything later than this will cause the iterator to stop */
+    protected $cutoff;
+
+    /**
+     * Constructor.
+     *
+     * @param \Iterator $parent Parent iterator, must return search documents in modified order
+     * @param int $cutoff Cut-off time, default is current time
+     */
+    public function __construct(\Iterator $parent, $cutoff = 0) {
+        $this->parent = $parent;
+        if ($cutoff) {
+            $this->cutoff = $cutoff;
+        } else {
+            $this->cutoff = time();
+        }
+    }
+
+    public function current() {
+        return $this->parent->current();
+    }
+
+    public function next() {
+        $this->parent->next();
+    }
+
+    public function key() {
+        return $this->parent->key();
+    }
+
+    public function valid() {
+        // Check parent.
+        if (!$this->parent->valid()) {
+            return false;
+        }
+
+        // See if document is after the cut-off time.
+        $doc = $this->parent->current();
+        if ($doc->get('modified') > $this->cutoff) {
+            return false;
+        }
+
+        return true;
+    }
+
+    public function rewind() {
+        $this->parent->rewind();
+    }
+}