Added WATCH, UNWATCH, with doc and unit tests.

Author: nicolasff

README.markdown

@@ -167,6 +167,23 @@ $ret == array(
 */
 </pre>
 
+## watch, unwatch
+##### Description
+Watches a key for modifications by another client. If the key is modified between `WATCH` and `EXEC`, the MULTI/EXEC transaction will fail (return `FALSE`). `unwatch` cancels all the watching of all keys by this client.
+##### Parameters
+*keys*: a list of keys
+##### Example
+<pre>
+$redis->watch('x');
+/* long code here during the execution of which other clients could well modify `x` */
+$ret = $redis->multi()
+    ->incr('x')
+    ->exec();
+/*
+$ret = FALSE if x has been modified between the call to WATCH and the call to EXEC.
+*/
+</pre>
+
 ## exists
 ##### Description
 Verify if the specified key exists.

php_redis.h

@@ -113,6 +113,8 @@ PHP_METHOD(Redis, hMset);
 PHP_METHOD(Redis, multi);
 PHP_METHOD(Redis, discard);
 PHP_METHOD(Redis, exec);
+PHP_METHOD(Redis, watch);
+PHP_METHOD(Redis, unwatch);
 
 PHP_METHOD(Redis, pipeline);
 

redis.c

@@ -144,6 +144,8 @@ static zend_function_entry redis_functions[] = {
      PHP_ME(Redis, discard, NULL, ZEND_ACC_PUBLIC)
      PHP_ME(Redis, exec, NULL, ZEND_ACC_PUBLIC)
      PHP_ME(Redis, pipeline, NULL, ZEND_ACC_PUBLIC)
+     PHP_ME(Redis, watch, NULL, ZEND_ACC_PUBLIC)
+     PHP_ME(Redis, unwatch, NULL, ZEND_ACC_PUBLIC)
 
 	 PHP_ME(Redis, publish, NULL, ZEND_ACC_PUBLIC)
 	 PHP_ME(Redis, subscribe, NULL, ZEND_ACC_PUBLIC)
@@ -1007,6 +1009,35 @@ PHP_METHOD(Redis, delete)
 }
 /* }}} */
 
+/* {{{ proto boolean Redis::watch(string key1, string key2...)
+ */
+PHP_METHOD(Redis, watch)
+{
+    RedisSock *redis_sock;
+
+    generic_multiple_args_cmd(INTERNAL_FUNCTION_PARAM_PASSTHRU,
+                    "WATCH", sizeof("WATCH") - 1,
+                    1, &redis_sock);
+	zval * object = getThis();
+
+    IF_ATOMIC() {
+	  redis_boolean_response(INTERNAL_FUNCTION_PARAM_PASSTHRU, redis_sock, NULL);
+    }
+	REDIS_PROCESS_RESPONSE(redis_boolean_response);
+
+}
+/* }}} */
+
+/* {{{ proto boolean Redis::unwatch()
+ */
+PHP_METHOD(Redis, unwatch)
+{
+    char cmd[] = "*1" _NL "$7" _NL "UNWATCH" _NL;
+    generic_empty_cmd(INTERNAL_FUNCTION_PARAM_PASSTHRU, estrdup(cmd), sizeof(cmd)-1);
+
+}
+/* }}} */
+
 /* {{{ proto array Redis::getKeys(string pattern)
  */
 PHP_METHOD(Redis, getKeys)
@@ -4128,8 +4159,11 @@ PHPAPI int redis_sock_read_multibulk_multi_reply(INTERNAL_FUNCTION_PARAMETERS,
 	/* number of responses */
     int numElems = atoi(inbuf+1);
 
-    zval_dtor(return_value);
+    if(numElems < 0) {
+        return -1;
+    }
 
+    zval_dtor(return_value);
     zval *z_tab;
     MAKE_STD_ZVAL(z_tab);
     array_init(z_tab);
@@ -4200,6 +4234,7 @@ PHP_METHOD(Redis, exec)
 	    if (redis_sock_read_multibulk_multi_reply(INTERNAL_FUNCTION_PARAM_PASSTHRU, redis_sock) < 0) {
             zval_dtor(return_value);
             free_reply_callbacks(object);
+            set_flag(object, REDIS_ATOMIC TSRMLS_CC);
 			RETURN_FALSE;
 	    }
         free_reply_callbacks(object);

tests/TestRedis.php

@@ -12,11 +12,17 @@ class Redis_Test extends PHPUnit_Framework_TestCase
 
     public function setUp()
     {
-	$this->redis = new Redis();
-	$this->redis->connect('127.0.0.1', 6379);
+	$this->redis = $this->newInstance();
+    }
+
+    private function newInstance() {
+	$r = new Redis();
+	$r->connect('127.0.0.1', 6379);
 
 	// uncomment the following if you want to use authentication
-	// $this->assertTrue($this->redis->auth('foobared'));
+	// $this->assertTrue($r->auth('foobared'));
+
+	return $r;
     }
 
     public function tearDown()
@@ -1592,6 +1598,37 @@ public function testHashes() {
 
     public function testMultiExec() {
 	$this->sequence(Redis::MULTI);
+
+	$this->redis->set('x', '42');
+
+	$this->assertTrue(TRUE === $this->redis->watch('x'));
+	$ret = $this->redis->multi()
+		->get('x')
+		->exec();
+
+	// successful transaction
+	$this->assertTrue($ret === array('42'));
+
+	// failed transaction
+	$this->redis->watch('x');
+
+	$r = $this->newInstance(); // new instance, modifying `x'.
+	$r->incr('x');
+
+	$ret = $this->redis->multi()
+		->get('x')
+		->exec();
+	$this->assertTrue($ret === FALSE); // failed because another client changed our watched key between WATCH and EXEC.
+
+	// watch and unwatch
+	$this->redis->watch('x');
+	$r->incr('x'); // other instance
+	$this->redis->unwatch(); // cancel transaction watch
+
+	$ret = $this->redis->multi()
+		->get('x')
+		->exec();
+	$this->assertTrue($ret === array('44')); // succeeded since we've cancel the WATCH command.
     }
 
     public function testPipeline() {
@@ -1769,6 +1806,9 @@ protected function sequence($mode) {
 		    ->dbSize()
 		    ->lastsave()
 		    ->exec();
+
+	    $this->redis->select(0); // back to normal
+
 	    $i = 0;
 	    $this->assertTrue(is_array($ret));
 	    $this->assertTrue($ret[$i++] === TRUE); // select