From 6ca054d91e3bd6a3a84a96476c2b234c412ae52b Mon Sep 17 00:00:00 2001
From: Stan Misiurev <smisiurev@gmail.com>
Date: Sat, 29 Aug 2015 21:29:23 -0400
Subject: [PATCH] nested transactions

---
 lib/Connection.php           | 26 ++++++++++++++++++++++++--
 test/helpers/AdapterTest.php | 29 +++++++++++++++++++++++++++++
 2 files changed, 53 insertions(+), 2 deletions(-)
 mode change 100644 => 100755 lib/Connection.php
 mode change 100644 => 100755 test/helpers/AdapterTest.php

diff --git a/lib/Connection.php b/lib/Connection.php
old mode 100644
new mode 100755
index c32311bcb..98495cbde
--- a/lib/Connection.php
+++ b/lib/Connection.php
@@ -77,6 +77,12 @@ abstract class Connection
 	 */
 	static $DEFAULT_PORT = 0;
 
+    /**
+     * Number of nested transactions
+     * @var int
+     */
+    static protected $transaction_counter = 0;
+
 	/**
 	 * Retrieve a database connection.
 	 *
@@ -376,8 +382,14 @@ public function tables()
 	 */
 	public function transaction()
 	{
-		if (!$this->connection->beginTransaction())
-			throw new DatabaseException($this);
+        // Transaction started already
+        if (static::$transaction_counter++) {
+            $this->connection->exec('SAVEPOINT trans'.static::$transaction_counter);
+            return;
+        }
+
+        if (!$this->connection->beginTransaction())
+           throw new DatabaseException($this);
 	}
 
 	/**
@@ -385,6 +397,11 @@ public function transaction()
 	 */
 	public function commit()
 	{
+        // Nested transaction simply decrease number
+        if (--static::$transaction_counter) {
+            return;
+        }
+
 		if (!$this->connection->commit())
 			throw new DatabaseException($this);
 	}
@@ -394,6 +411,11 @@ public function commit()
 	 */
 	public function rollback()
 	{
+        if (--static::$transaction_counter) {
+            $this->connection->exec('ROLLBACK TO trans'.(static::$transaction_counter + 1));
+            return true;
+        }
+
 		if (!$this->connection->rollback())
 			throw new DatabaseException($this);
 	}
diff --git a/test/helpers/AdapterTest.php b/test/helpers/AdapterTest.php
old mode 100644
new mode 100755
index 97685f6bc..d4a662f0d
--- a/test/helpers/AdapterTest.php
+++ b/test/helpers/AdapterTest.php
@@ -407,5 +407,34 @@ public function test_date_to_string()
 		$datetime = '2009-01-01';
 		$this->assert_equals($datetime,$this->conn->date_to_string(date_create($datetime)));
 	}
+
+
+    public function test_transaction_nested_commit()
+    {
+        $original = $this->conn->query_and_fetch_one("select count(*) from authors");
+
+        $this->conn->transaction();
+        $this->conn->query("insert into authors(author_id,name) values(9998,'blahhhhhhhh')");
+        // Nested
+        $this->conn->transaction();
+        $this->conn->query("insert into authors(author_id,name) values(9999,'blahhhhhhhh')");
+        $this->conn->commit();
+
+        // Another nested
+        try {
+            $this->conn->transaction();
+            $this->conn->query("insert into authors(author_id,name) values(9999,'blahhhhhhhh')"); // fails
+            $this->conn->commit();
+        }
+        catch (Exception $e)
+        {
+            $this->conn->rollback();
+        }
+
+        // Commit primary transaction
+        $this->conn->commit();
+
+        $this->assert_equals($original+2, $this->conn->query_and_fetch_one("select count(*) from authors"));
+    }
 }
 ?>