PHPC-255: Cursors cannot rewind after starting iteration

Author: jmikola

php_phongo.c

@@ -1673,6 +1673,11 @@ static void php_phongo_cursor_iterator_rewind(zend_object_iterator *iter TSRMLS_
 	php_phongo_cursor_t        *cursor = cursor_it->cursor;
 	const bson_t               *doc;
 
+	if (cursor_it->current > 0) {
+		phongo_throw_exception(PHONGO_ERROR_LOGIC TSRMLS_CC, "Cursors cannot rewind after starting iteration");
+		return;
+	}
+
 	php_phongo_cursor_free_current(cursor);
 
 	doc = mongoc_cursor_current(cursor->cursor);

tests/standalone/cursor-iterator_handlers-001.phpt

@@ -51,10 +51,6 @@ echo "\nAfter advancing, next element is populated:\n";
 $a->next();
 $a->dump();
 
-echo "\nRewinding only populates current element and does not alter position:\n";
-$a->rewind();
-$a->dump();
-
 echo "\nAdvancing through remaining elements:\n";
 $a->next();
 $a->dump();
@@ -82,9 +78,6 @@ A: 0 => {_id: 0}
 After advancing, next element is populated:
 A: 1 => {_id: 1}
 
-Rewinding only populates current element and does not alter position:
-A: 1 => {_id: 1}
-
 Advancing through remaining elements:
 A: 2 => {_id: 2}
 A: 3 => {_id: 3}

tests/standalone/cursor-rewind-001.phpt

@@ -0,0 +1,100 @@
+--TEST--
+MongoDB\Driver\Cursor cannot rewind after starting iteration
+--SKIPIF--
+<?php require __DIR__ . "/../utils/basic-skipif.inc"; CLEANUP(STANDALONE) ?>
+--FILE--
+<?php
+require_once __DIR__ . "/../utils/basic.inc";
+
+class MyIteratorIterator extends IteratorIterator
+{
+    private $name;
+
+    public function __construct(Traversable $iterator, $name)
+    {
+        parent::__construct($iterator);
+        $this->name = (string) $name;
+    }
+
+    public function dump()
+    {
+        $key = parent::key();
+        $current = parent::current();
+        $position = is_int($key) ? (string) $key : 'null';
+        $document = is_array($current) ? sprintf("{_id: %d}", $current['_id']) : 'null';
+        printf("%s: %s => %s\n", $this->name, $position, $document);
+    }
+}
+
+$manager = new MongoDB\Driver\Manager(STANDALONE);
+
+$bulkWrite = new MongoDB\Driver\BulkWrite;
+
+for ($i = 0; $i < 5; $i++) {
+    $bulkWrite->insert(array('_id' => $i));
+}
+
+$writeResult = $manager->executeBulkWrite(NS, $bulkWrite);
+printf("Inserted: %d\n", $writeResult->getInsertedCount());
+
+$cursor = $manager->executeQuery(NS, new MongoDB\Driver\Query(array()));
+$a = new MyIteratorIterator($cursor, 'A');
+
+echo "\nRewinding sets the current element:\n";
+$a->rewind();
+$a->dump();
+
+echo "\nRewinding again is OK since we haven't advanced:\n";
+$a->rewind();
+$a->dump();
+
+echo "\nAdvancing populates the next element:\n";
+$a->next();
+$a->dump();
+
+echo "\nRewinding after advancing is not OK:\n";
+try {
+    $a->rewind();
+    echo "FAILED: rewind should throw if iteration has started\n";
+} catch (MongoDB\Driver\Exception\LogicException $e) {
+    printf("LogicException: %s\n", $e->getMessage());
+}
+
+echo "\nAdvancing through remaining elements:\n";
+$a->next();
+$a->dump();
+$a->next();
+$a->dump();
+$a->next();
+$a->dump();
+
+echo "\nAdvancing beyond the last element:\n";
+$a->next();
+$a->dump();
+
+?>
+===DONE===
+<?php exit(0); ?>
+--EXPECT--
+Inserted: 5
+
+Rewinding sets the current element:
+A: 0 => {_id: 0}
+
+Rewinding again is OK since we haven't advanced:
+A: 0 => {_id: 0}
+
+Advancing populates the next element:
+A: 1 => {_id: 1}
+
+Rewinding after advancing is not OK:
+LogicException: Cursors cannot rewind after starting iteration
+
+Advancing through remaining elements:
+A: 2 => {_id: 2}
+A: 3 => {_id: 3}
+A: 4 => {_id: 4}
+
+Advancing beyond the last element:
+A: null => null
+===DONE===