Provide retry callback with the attempt count

This provides the call back with a attempt count, this can be helpful
for function that need to modify there behavior with each attempt, or
log it some how.

Author: AJenbo

src/Illuminate/Support/helpers.php

@@ -739,19 +739,21 @@ function preg_replace_array($pattern, array $replacements, $subject)
      * Retry an operation a given number of times.
      *
      * @param  int  $times
-     * @param  callable  $callback
+     * @param  callable  $callback First parameter is the number of attempt
      * @param  int  $sleep
      * @return mixed
      *
      * @throws \Exception
      */
     function retry($times, callable $callback, $sleep = 0)
     {
+        $attempt = 0;
         $times--;
 
         beginning:
+        $attempt++;
         try {
-            return $callback();
+            return $callback($attempt);
         } catch (Exception $e) {
             if (! $times) {
                 throw $e;

tests/Support/SupportHelpersTest.php

@@ -868,6 +868,25 @@ public function something()
         })->present()->something());
     }
 
+    public function testRetry()
+    {
+        $startTime = microtime(true);
+
+        $attempts = retry(2, function ($attempts) {
+            if ($attempts > 1) {
+                return $attempts;
+            }
+
+            throw new RuntimeException;
+        }, 100);
+
+        // Make sure we made two attempts
+        $this->assertEquals(2, $attempts);
+
+        // Make sure we waited 100ms for the first attempt
+        $this->assertTrue(microtime(true) - $startTime >= 0.1);
+    }
+
     public function testTransform()
     {
         $this->assertEquals(10, transform(5, function ($value) {