Add check to Store::unlock to ensure file exists

Fix indentation and shorten code

src/Symfony/Component/HttpKernel/HttpCache/Store.php

@@ -86,10 +86,14 @@ class Store implements StoreInterface
      * Releases the lock for the given Request.
      *
      * @param Request $request A Request instance
+     *
+     * @return Boolean False if the lock file does not exist or cannot be unlocked, true otherwise
      */
     public function unlock(Request $request)
     {
-        return @unlink($this->getPath($this->getCacheKey($request).'.lck'));
+        $file = $this->getPath($this->getCacheKey($request).'.lck');
+
+        return is_file($file) ? @unlink($file) : false;
     }
 
     /**

src/Symfony/Component/HttpKernel/HttpCache/StoreInterface.php

@@ -66,6 +66,8 @@ interface StoreInterface
      * Releases the lock for the given Request.
      *
      * @param Request $request A Request instance
+     *
+     * @return Boolean False if the lock file does not exist or cannot be unlocked, true otherwise
      */
     public function unlock(Request $request);
 

tests/Symfony/Tests/Component/HttpKernel/HttpCache/StoreTest.php

@@ -19,8 +19,19 @@ use Symfony\Component\HttpKernel\HttpCache\Store;
 
 class StoreTest extends \PHPUnit_Framework_TestCase
 {
+    /**
+     * @var Request
+     */
     protected $request;
+
+    /**
+     * @var Response
+     */
     protected $response;
+
+    /**
+     * @var Store
+     */
     protected $store;
 
     protected function setUp()
@@ -47,6 +58,19 @@ class StoreTest extends \PHPUnit_Framework_TestCase
         $this->assertEmpty($this->getStoreMetadata('/nothing'));
     }
 
+    public function testUnlockFileThatDoesExist()
+    {
+        $cacheKey = $this->storeSimpleEntry();
+        $this->store->lock($this->request);
+
+        $this->assertTrue($this->store->unlock($this->request));
+    }
+
+    public function testUnlockFileThatDoesNotExist()
+    {
+        $this->assertFalse($this->store->unlock($this->request));
+    }
+
     public function testRemovesEntriesForKeyWithPurge()
     {
         $request = Request::create('/foo');