Merge pull request #2718 from jenkoian/efficient-iterating

Add iterators for non pdo drivers.

lib/Doctrine/DBAL/Driver/IBMDB2/DB2Statement.php

@@ -20,6 +20,7 @@
 namespace Doctrine\DBAL\Driver\IBMDB2;
 
 use Doctrine\DBAL\Driver\Statement;
+use Doctrine\DBAL\Driver\StatementIterator;
 
 class DB2Statement implements \IteratorAggregate, Statement
 {
@@ -199,9 +200,7 @@ class DB2Statement implements \IteratorAggregate, Statement
      */
     public function getIterator()
     {
-        $data = $this->fetchAll();
-
-        return new \ArrayIterator($data);
+        return new StatementIterator($this);
     }
 
     /**

lib/Doctrine/DBAL/Driver/Mysqli/MysqliStatement.php

@@ -20,6 +20,7 @@
 namespace Doctrine\DBAL\Driver\Mysqli;
 
 use Doctrine\DBAL\Driver\Statement;
+use Doctrine\DBAL\Driver\StatementIterator;
 use PDO;
 
 /**
@@ -406,8 +407,6 @@ class MysqliStatement implements \IteratorAggregate, Statement
      */
     public function getIterator()
     {
-        $data = $this->fetchAll();
-
-        return new \ArrayIterator($data);
+        return new StatementIterator($this);
     }
 }

lib/Doctrine/DBAL/Driver/OCI8/OCI8Connection.php

@@ -21,7 +21,6 @@ namespace Doctrine\DBAL\Driver\OCI8;
 
 use Doctrine\DBAL\Driver\Connection;
 use Doctrine\DBAL\Driver\ServerInfoAwareConnection;
-use Doctrine\DBAL\Platforms\OraclePlatform;
 
 /**
  * OCI8 implementation of the Connection interface.

lib/Doctrine/DBAL/Driver/OCI8/OCI8Statement.php

@@ -20,6 +20,8 @@
 namespace Doctrine\DBAL\Driver\OCI8;
 
 use Doctrine\DBAL\Driver\Statement;
+use Doctrine\DBAL\Driver\StatementIterator;
+use IteratorAggregate;
 use PDO;
 
 /**
@@ -28,7 +30,7 @@ use PDO;
  * @since 2.0
  * @author Roman Borschel <roman@code-factory.org>
  */
-class OCI8Statement implements \IteratorAggregate, Statement
+class OCI8Statement implements IteratorAggregate, Statement
 {
     /**
      * @var resource
@@ -369,9 +371,7 @@ class OCI8Statement implements \IteratorAggregate, Statement
      */
     public function getIterator()
     {
-        $data = $this->fetchAll();
-
-        return new \ArrayIterator($data);
+        return new StatementIterator($this);
     }
 
     /**

lib/Doctrine/DBAL/Driver/SQLAnywhere/SQLAnywhereStatement.php

@@ -19,6 +19,7 @@
 
 namespace Doctrine\DBAL\Driver\SQLAnywhere;
 
+use Doctrine\DBAL\Driver\StatementIterator;
 use IteratorAggregate;
 use PDO;
 use Doctrine\DBAL\Driver\Statement;
@@ -278,7 +279,7 @@ class SQLAnywhereStatement implements IteratorAggregate, Statement
      */
     public function getIterator()
     {
-        return new \ArrayIterator($this->fetchAll());
+        return new StatementIterator($this);
     }
 
     /**

lib/Doctrine/DBAL/Driver/SQLSrv/SQLSrvStatement.php

@@ -19,6 +19,7 @@
 
 namespace Doctrine\DBAL\Driver\SQLSrv;
 
+use Doctrine\DBAL\Driver\StatementIterator;
 use PDO;
 use IteratorAggregate;
 use Doctrine\DBAL\Driver\Statement;
@@ -295,9 +296,7 @@ class SQLSrvStatement implements IteratorAggregate, Statement
      */
     public function getIterator()
     {
-        $data = $this->fetchAll();
-
-        return new \ArrayIterator($data);
+        return new StatementIterator($this);
     }
 
     /**

lib/Doctrine/DBAL/Driver/StatementIterator.php

+<?php
+
+namespace Doctrine\DBAL\Driver;
+
+class StatementIterator implements \IteratorAggregate
+{
+    /**
+     * @var Statement
+     */
+    private $statement;
+
+    /**
+     * @param Statement $statement
+     */
+    public function __construct(Statement $statement)
+    {
+        $this->statement = $statement;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function getIterator()
+    {
+        while (false !== ($result = $this->statement->fetch())) {
+            yield $result;
+        }
+    }
+}

tests/Doctrine/Tests/DBAL/Driver/StatementIteratorTest.php

+<?php
+
+namespace Doctrine\Tests\DBAL\Driver;
+
+use Doctrine\DBAL\Driver\Statement;
+use Doctrine\DBAL\Driver\StatementIterator;
+
+class StatementIteratorTest extends \Doctrine\Tests\DbalTestCase
+{
+    public function testGettingIteratorDoesNotCallFetch()
+    {
+        $stmt = $this->createMock(Statement::class);
+        $stmt->expects($this->never())->method('fetch');
+        $stmt->expects($this->never())->method('fetchAll');
+        $stmt->expects($this->never())->method('fetchColumn');
+
+        $stmtIterator = new StatementIterator($stmt);
+        $stmtIterator->getIterator();
+    }
+
+    public function testIterationCallsFetchOncePerStep()
+    {
+        $values = ['foo', '', 'bar', '0', 'baz', 0, 'qux', null, 'quz', false, 'impossible'];
+        $calls = 0;
+
+        $stmt = $this->createMock(Statement::class);
+        $stmt->expects($this->exactly(10))
+            ->method('fetch')
+            ->willReturnCallback(function() use ($values, &$calls) {
+                $value = $values[$calls];
+                $calls++;
+                return $value;
+            });
+
+        $stmtIterator = new StatementIterator($stmt);
+        foreach ($stmtIterator as $i => $_) {
+            $this->assertEquals($i + 1, $calls);
+        }
+    }
+}