add nested transactions (mysql >= 5.5 only)

db.class.php

@@ -35,6 +35,7 @@ class DB {
   public static $throw_exception_on_error = false;
   public static $nonsql_error_handler = null;
   public static $throw_exception_on_nonsql_error = false;
+  public static $nested_transactions = false;
   
   // internal
   protected static $mdb = null;
@@ -54,10 +55,12 @@ class DB {
     if ($mdb->throw_exception_on_error !== DB::$throw_exception_on_error) $mdb->throw_exception_on_error = DB::$throw_exception_on_error;
     if ($mdb->nonsql_error_handler !== DB::$nonsql_error_handler) $mdb->nonsql_error_handler = DB::$nonsql_error_handler;
     if ($mdb->throw_exception_on_nonsql_error !== DB::$throw_exception_on_nonsql_error) $mdb->throw_exception_on_nonsql_error = DB::$throw_exception_on_nonsql_error;
+    if ($mdb->nested_transactions !== DB::$nested_transactions) $mdb->nested_transactions = DB::$nested_transactions;
     
     return $mdb;
   }
   
+  public static function get() { $args = func_get_args(); return call_user_func_array(array(DB::getMDB(), 'get'), $args); }
   public static function query() { $args = func_get_args(); return call_user_func_array(array(DB::getMDB(), 'query'), $args); }
   public static function quickPrepare() { $args = func_get_args(); return call_user_func_array(array(DB::getMDB(), 'quickPrepare'), $args); }
   public static function queryFirstRow() { $args = func_get_args(); return call_user_func_array(array(DB::getMDB(), 'queryFirstRow'), $args); }
@@ -94,6 +97,8 @@ class DB {
   public static function sqlEval() { $args = func_get_args(); return call_user_func_array(array(DB::getMDB(), 'sqlEval'), $args); }
   public static function nonSQLError() { $args = func_get_args(); return call_user_func_array(array(DB::getMDB(), 'nonSQLError'), $args); }
   
+  public static function serverVersion() { $args = func_get_args(); return call_user_func_array(array(DB::getMDB(), 'serverVersion'), $args); }
+  
   public static function debugMode($handler = true) { 
     DB::$success_handler = $handler;
   }
@@ -119,9 +124,11 @@ class MeekroDB {
   public $throw_exception_on_error = false;
   public $nonsql_error_handler = null;
   public $throw_exception_on_nonsql_error = false;
+  public $nested_transactions = false;
   
   // internal
   public $internal_mysql = null;
+  public $server_info = null;
   public $insert_id = 0;
   public $num_rows = 0;
   public $affected_rows = 0;
@@ -129,6 +136,7 @@ class MeekroDB {
   public $queryResultType = null;
   public $old_db = null;
   public $current_db = null;
+  public $nested_transactions_count = 0;
   
   
   public function __construct($host=null, $user=null, $password=null, $dbName=null, $port=null, $encoding=null) {
@@ -161,6 +169,7 @@ class MeekroDB {
       
       $mysql->set_charset($this->encoding);
       $this->internal_mysql = $mysql;
+      $this->server_info = $mysql->server_info;
     }
     
     return $mysql;
@@ -184,6 +193,7 @@ class MeekroDB {
     $this->success_handler = $handler;
   }
   
+  public function serverVersion() { return $this->server_info; }
   public function insertId() { return $this->insert_id; }
   public function affectedRows() { return $this->affected_rows; }
   public function count() { $args = func_get_args(); return call_user_func_array(array($this, 'numRows'), $args); }
@@ -199,15 +209,51 @@ class MeekroDB {
   
   
   public function startTransaction() {
-    $this->queryNull('START TRANSACTION');
+    if ($this->nested_transactions && $this->serverVersion() < '5.5') {
+      return $this->nonSQLError("Nested transactions are only available on MySQL 5.5 and greater. You are using MySQL " . $this->serverVersion());
+    }
+    
+    if (!$this->nested_transactions || $this->nested_transactions_count == 0) {
+      $this->queryNull('START TRANSACTION');
+    } else {
+      $this->queryNull("SAVEPOINT LEVEL{$this->nested_transactions_count}");
+    }
+    
+    if ($this->nested_transactions) return ++$this->nested_transactions_count;
   }
   
   public function commit() {
-    $this->queryNull('COMMIT');
+    if ($this->nested_transactions && $this->serverVersion() < '5.5') {
+      return $this->nonSQLError("Nested transactions are only available on MySQL 5.5 and greater. You are using MySQL " . $this->serverVersion());
+    }
+    
+    if ($this->nested_transactions && $this->nested_transactions_count > 0)
+      $this->nested_transactions_count--;
+    
+    if (!$this->nested_transactions || $this->nested_transactions_count == 0) {
+      $this->queryNull('COMMIT');
+    } else {
+      $this->queryNull("RELEASE SAVEPOINT LEVEL{$this->nested_transactions_count}");
+    }
+    
+    return $this->nested_transactions_count;
   }
   
   public function rollback() {
-    $this->queryNull('ROLLBACK');
+    if ($this->nested_transactions && $this->serverVersion() < '5.5') {
+      return $this->nonSQLError("Nested transactions are only available on MySQL 5.5 and greater. You are using MySQL " . $this->serverVersion());
+    }
+    
+    if ($this->nested_transactions && $this->nested_transactions_count > 0)
+      $this->nested_transactions_count--;
+    
+    if (!$this->nested_transactions || $this->nested_transactions_count == 0) {
+      $this->queryNull('ROLLBACK');
+    } else {
+      $this->queryNull("ROLLBACK TO SAVEPOINT LEVEL{$this->nested_transactions_count}");
+    }
+    
+    return $this->nested_transactions_count;
   }
   
   public function escape($str) {

simpletest/TransactionTest.php

@@ -0,0 +1,24 @@
+<?
+class TransactionTest extends SimpleTest {
+  function test_1_transactions() {
+    DB::$nested_transactions = false;
+    
+    DB::query("UPDATE accounts SET age=%i WHERE username=%s", 600, 'Abe');
+    
+    DB::startTransaction();
+    DB::query("UPDATE accounts SET age=%i WHERE username=%s", 700, 'Abe');
+    DB::startTransaction();
+    DB::query("UPDATE accounts SET age=%i WHERE username=%s", 800, 'Abe');
+    DB::rollback();
+    
+    $age = DB::queryFirstField("SELECT age FROM accounts WHERE username=%s", 'Abe');
+    $this->assert($age == 700);
+    
+    DB::rollback();
+    
+    $age = DB::queryFirstField("SELECT age FROM accounts WHERE username=%s", 'Abe');
+    $this->assert($age == 700);
+  }
+  
+}
+?>

simpletest/TransactionTest_55.php

@@ -0,0 +1,63 @@
+<?
+class TransactionTest_55 extends SimpleTest {
+  function test_1_transactions() {
+    DB::$nested_transactions = true;
+    
+    $depth = DB::startTransaction();
+      $this->assert($depth === 1);
+      DB::query("UPDATE accounts SET age=%i WHERE username=%s", 700, 'Abe');
+      
+      $depth = DB::startTransaction();
+        $this->assert($depth === 2);
+        DB::query("UPDATE accounts SET age=%i WHERE username=%s", 800, 'Abe');
+        
+        $depth = DB::startTransaction();
+          $this->assert($depth === 3);
+          DB::query("UPDATE accounts SET age=%i WHERE username=%s", 500, 'Abe');
+        $depth = DB::commit();
+        
+        $this->assert($depth === 2);
+        
+        $age = DB::queryFirstField("SELECT age FROM accounts WHERE username=%s", 'Abe');
+        $this->assert($age == 500);
+        
+      $depth = DB::rollback();
+      $this->assert($depth === 1);
+      
+      $age = DB::queryFirstField("SELECT age FROM accounts WHERE username=%s", 'Abe');
+      $this->assert($age == 700);
+    
+    $depth = DB::commit();
+    $this->assert($depth === 0);
+    
+    $age = DB::queryFirstField("SELECT age FROM accounts WHERE username=%s", 'Abe');
+    $this->assert($age == 700);
+    
+    
+    DB::$nested_transactions = false;
+  }
+  
+  function test_2_transactions() {
+    DB::$nested_transactions = true;
+    
+    DB::query("UPDATE accounts SET age=%i WHERE username=%s", 600, 'Abe');
+    
+    DB::startTransaction();
+    DB::query("UPDATE accounts SET age=%i WHERE username=%s", 700, 'Abe');
+    DB::startTransaction();
+    DB::query("UPDATE accounts SET age=%i WHERE username=%s", 800, 'Abe');
+    DB::rollback();
+    
+    $age = DB::queryFirstField("SELECT age FROM accounts WHERE username=%s", 'Abe');
+    $this->assert($age == 700);
+    
+    DB::rollback();
+    
+    $age = DB::queryFirstField("SELECT age FROM accounts WHERE username=%s", 'Abe');
+    $this->assert($age == 600);
+    
+    DB::$nested_transactions = false;
+  }
+  
+}
+?>

simpletest/test.php

@@ -25,23 +25,25 @@ else $is_php_53 = false;
 
 error_reporting(E_ALL | E_STRICT);
 require_once '../db.class.php';
-DB::$user = 'meekrodb_test_us';
-
 include 'test_setup.php'; //test config values go here
+DB::$user = $set_db_user;
 DB::$password = $set_password;
 DB::$dbName = $set_db;
 DB::$host = $set_host;
+DB::get(); //connect to mysql
 
 require_once 'BasicTest.php';
 require_once 'ObjectTest.php';
 require_once 'WhereClauseTest.php';
 require_once 'ErrorTest.php';
+require_once 'TransactionTest.php';
 
 $classes_to_test = array(
   'BasicTest',
   'WhereClauseTest',
   'ObjectTest',
   'ErrorTest',
+  'TransactionTest',
 );
 
 if ($is_php_53) {
@@ -51,6 +53,14 @@ if ($is_php_53) {
   echo "PHP 5.3 not detected, skipping 5.3 tests..\n";
 }
 
+$mysql_version = DB::serverVersion();
+if ($mysql_version >= '5.5') {
+  require_once 'TransactionTest_55.php';
+  $classes_to_test[] = 'TransactionTest_55';
+} else {
+  echo "MySQL 5.5 not available (version is $mysql_version) -- skipping MySQL 5.5 tests\n";
+}
+
 $time_start = microtime_float();
 foreach ($classes_to_test as $class) {
   $object = new $class();