PHPLIB-81: Cache cursors for collection and index enumeration

This will allow the returned CollectionInfoIterator and IndexInfoIterator classes to be rewound and iterated multiple times.

Author: jmikola

src/Operation/ListCollections.php

@@ -22,6 +22,7 @@
 use MongoDB\Driver\Server;
 use MongoDB\Driver\Exception\RuntimeException as DriverRuntimeException;
 use MongoDB\Exception\InvalidArgumentException;
+use MongoDB\Model\CachingIterator;
 use MongoDB\Model\CollectionInfoCommandIterator;
 use MongoDB\Model\CollectionInfoIterator;
 use MongoDB\Model\CollectionInfoLegacyIterator;
@@ -107,7 +108,7 @@ private function executeCommand(Server $server)
         $cursor = $server->executeCommand($this->databaseName, new Command($cmd));
         $cursor->setTypeMap(['root' => 'array', 'document' => 'array']);
 
-        return new CollectionInfoCommandIterator($cursor);
+        return new CollectionInfoCommandIterator(new CachingIterator($cursor));
     }
 
     /**
@@ -138,6 +139,6 @@ private function executeLegacy(Server $server)
         $cursor = $server->executeQuery($this->databaseName . '.system.namespaces', new Query($filter, $options));
         $cursor->setTypeMap(['root' => 'array', 'document' => 'array']);
 
-        return new CollectionInfoLegacyIterator($cursor);
+        return new CollectionInfoLegacyIterator(new CachingIterator($cursor));
     }
 }

src/Operation/ListIndexes.php

@@ -22,6 +22,7 @@
 use MongoDB\Driver\Server;
 use MongoDB\Driver\Exception\RuntimeException as DriverRuntimeException;
 use MongoDB\Exception\InvalidArgumentException;
+use MongoDB\Model\CachingIterator;
 use MongoDB\Model\IndexInfoIterator;
 use MongoDB\Model\IndexInfoIteratorIterator;
 use EmptyIterator;
@@ -114,7 +115,7 @@ private function executeCommand(Server $server)
 
         $cursor->setTypeMap(['root' => 'array', 'document' => 'array']);
 
-        return new IndexInfoIteratorIterator($cursor);
+        return new IndexInfoIteratorIterator(new CachingIterator($cursor));
     }
 
     /**
@@ -136,6 +137,6 @@ private function executeLegacy(Server $server)
         $cursor = $server->executeQuery($this->databaseName . '.system.indexes', new Query($filter, $options));
         $cursor->setTypeMap(['root' => 'array', 'document' => 'array']);
 
-        return new IndexInfoIteratorIterator($cursor);
+        return new IndexInfoIteratorIterator(new CachingIterator($cursor));
     }
 }

tests/Operation/ListCollectionsFunctionalTest.php

@@ -20,8 +20,9 @@ public function testListCollectionsForNewlyCreatedDatabase()
         $this->assertEquals(1, $writeResult->getInsertedCount());
 
         $operation = new ListCollections($this->getDatabaseName(), ['filter' => ['name' => $this->getCollectionName()]]);
-        // Convert the CollectionInfoIterator to an array since we cannot rewind its cursor
-        $collections = iterator_to_array($operation->execute($server));
+        $collections = $operation->execute($server);
+
+        $this->assertInstanceOf('MongoDB\Model\CollectionInfoIterator', $collections);
 
         $this->assertCount(1, $collections);
 

tests/Operation/ListIndexesFunctionalTest.php

@@ -22,9 +22,6 @@ public function testListIndexesForNewlyCreatedCollection()
 
         $this->assertInstanceOf('MongoDB\Model\IndexInfoIterator', $indexes);
 
-        // Convert the CursorInfoIterator to an array since we cannot rewind its cursor
-        $indexes = iterator_to_array($indexes);
-
         $this->assertCount(1, $indexes);
 
         foreach ($indexes as $index) {