From 8ec333effc49d602f26cc43937324a554b3d1327 Mon Sep 17 00:00:00 2001
From: Bilge <bilge@scriptfusion.com>
Date: Wed, 18 Apr 2018 23:05:33 +0100
Subject: [PATCH] Added retryAsync() method.

---
 .gitignore         |    1 +
 .travis.yml        |   21 +-
 bin/test           |    5 -
 composer.json      |    6 +-
 composer.lock      | 1124 --------------------------------------------
 src/retry.php      |   56 ++-
 test/RetryTest.php |   69 ++-
 7 files changed, 125 insertions(+), 1157 deletions(-)
 delete mode 100755 bin/test
 delete mode 100644 composer.lock

diff --git a/.gitignore b/.gitignore
index ad9da58..74fbacf 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,2 +1,3 @@
 /vendor/
 /.*/
+/composer.lock
diff --git a/.travis.yml b/.travis.yml
index 06d2664..b5df7db 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -10,15 +10,28 @@ php:
   - 5.6
   - 7.0
   - 7.1
+  - 7.2
+
+env:
+  matrix:
+    -
+    - DEPENDENCIES=--prefer-lowest
+
+matrix:
+  fast_finish: true
+
+cache:
+  directories:
+    - vendor
 
 install:
   - alias composer=composer\ -n && composer selfupdate
   - composer validate
-  - composer --prefer-source install
+  - composer update --no-progress --no-suggest $DEPENDENCIES
 
 script:
-  - bin/test --coverage-clover=build/logs/clover.xml
+  - composer test -- --coverage-clover=build/logs/clover.xml
 
 after_success:
-  - composer --prefer-source require satooshi/php-coveralls
-  - vendor/bin/coveralls -v
+  - composer require php-coveralls/php-coveralls:^2
+  - vendor/bin/php-coveralls -v
diff --git a/bin/test b/bin/test
deleted file mode 100755
index 8d3beb6..0000000
--- a/bin/test
+++ /dev/null
@@ -1,5 +0,0 @@
-#!/usr/bin/env bash
-
-cd "$(dirname "$0")"/..
-
-vendor/bin/phpunit -c test "$@"
diff --git a/composer.json b/composer.json
index 387c7ac..5f8e7ef 100644
--- a/composer.json
+++ b/composer.json
@@ -16,7 +16,8 @@
     "php": "^5.5|^7"
   },
   "require-dev": {
-    "phpunit/phpunit": "^4"
+    "phpunit/phpunit": "^4.8",
+    "amphp/amp": "^2"
   },
   "autoload": {
     "files": [
@@ -25,5 +26,8 @@
     "psr-4": {
       "ScriptFUSION\\Retry\\": "src"
     }
+  },
+  "scripts": {
+    "test": "phpunit -c test"
   }
 }
diff --git a/composer.lock b/composer.lock
deleted file mode 100644
index fab0501..0000000
--- a/composer.lock
+++ /dev/null
@@ -1,1124 +0,0 @@
-{
-    "_readme": [
-        "This file locks the dependencies of your project to a known state",
-        "Read more about it at https://getcomposer.org/doc/01-basic-usage.md#composer-lock-the-lock-file",
-        "This file is @generated automatically"
-    ],
-    "hash": "6c5ad455bb73996e96823decc28e47d9",
-    "content-hash": "49ce23c064f14fc0e85f490231aa73b0",
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-                }
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-            "homepage": "http://www.phpdoc.org",
-            "keywords": [
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-                    "name": "Sebastian Bergmann",
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-                }
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-            "homepage": "http://www.github.com/sebastianbergmann/environment",
-            "keywords": [
-                "Xdebug",
-                "environment",
-                "hhvm"
-            ],
-            "time": "2016-05-17 03:18:57"
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-                    "email": "whatthejeff@gmail.com"
-                },
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-                    "email": "github@wallbash.com"
-                },
-                {
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-                    "email": "bschussek@2bepublished.at"
-                },
-                {
-                    "name": "Sebastian Bergmann",
-                    "email": "sebastian@phpunit.de"
-                },
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-                }
-            ],
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-            "homepage": "http://www.github.com/sebastianbergmann/exporter",
-            "keywords": [
-                "export",
-                "exporter"
-            ],
-            "time": "2016-06-17 09:04:28"
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-            "keywords": [
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-            ],
-            "time": "2015-10-12 03:26:01"
-        },
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-                    "email": "bschussek@gmail.com"
-                }
-            ],
-            "description": "Assertions to validate method input/output with nice error messages.",
-            "keywords": [
-                "assert",
-                "check",
-                "validate"
-            ],
-            "time": "2015-08-24 13:29:44"
-        }
-    ],
-    "aliases": [],
-    "minimum-stability": "stable",
-    "stability-flags": [],
-    "prefer-stable": false,
-    "prefer-lowest": false,
-    "platform": {
-        "php": "^5.5|^7"
-    },
-    "platform-dev": []
-}
diff --git a/src/retry.php b/src/retry.php
index e1a9e60..ae428ee 100644
--- a/src/retry.php
+++ b/src/retry.php
@@ -1,6 +1,9 @@
 <?php
 namespace ScriptFUSION\Retry;
 
+use Amp\Coroutine;
+use Amp\Promise;
+
 /**
  * Tries the specified operation up to the specified number of times. If specified, the exception handler will be
  * called immediately before retrying the operation.
@@ -10,25 +13,54 @@
  * @param callable $onError Optional. Exception handler.
  *
  * @return mixed Result of running the operation if tries is greater than zero, otherwise null.
+ *
+ * @throws FailingTooHardException The maximum number of attempts was reached.
+ * @throws \UnexpectedValueException The operation returned an unsupported type.
  */
 function retry($tries, callable $operation, callable $onError = null)
 {
-    if (($tries |= 0) <= $attempts = 0) {
-        return;
-    }
+    /** @var \Generator $generator */
+    $generator = call_user_func(static function () use ($tries, $operation, $onError) {
+        if (($tries |= 0) <= $attempts = 0) {
+            return;
+        }
+
+        try {
+            beginning:
+
+            if (($result = $operation()) instanceof Promise) {
+                // Wait for promise to resolve.
+                $result = yield $result;
+            }
+        } catch (\Exception $exception) {
+            if ($tries === ++$attempts) {
+                throw new FailingTooHardException($attempts, $exception);
+            }
 
-    try {
-        beginning:
-        return $operation();
-    } catch (\Exception $exception) {
-        if ($tries === ++$attempts) {
-            throw new FailingTooHardException($attempts, $exception);
+            if ($onError && $onError($exception) === false) {
+                return;
+            }
+
+            goto beginning;
         }
 
-        if ($onError && $onError($exception) === false) {
-            return;
+        if ($result instanceof \Generator) {
+            throw new \UnexpectedValueException('Cannot retry a Generator. You probably meant something else.');
         }
 
-        goto beginning;
+        return $result;
+    });
+
+    // Normal code path: generator runs without yielding.
+    if (!$generator->valid()) {
+        return $generator->getReturn();
     }
+
+    // Async code path: generator yields promises.
+    return $generator;
+}
+
+function retryAsync($tries, callable $operation, callable $onError = null)
+{
+    return new Coroutine(retry($tries, $operation, $onError));
 }
diff --git a/test/RetryTest.php b/test/RetryTest.php
index b780977..2dcb940 100644
--- a/test/RetryTest.php
+++ b/test/RetryTest.php
@@ -1,6 +1,7 @@
 <?php
 namespace ScriptFUSIONTest\Retry;
 
+use Amp\Delayed;
 use ScriptFUSION\Retry\FailingTooHardException;
 
 final class RetryTest extends \PHPUnit_Framework_TestCase
@@ -9,7 +10,7 @@ public function testWithoutFailing()
     {
         $invocations = 0;
 
-        $value = \ScriptFUSION\Retry\retry($tries = 1, function () use (&$invocations) {
+        $value = \ScriptFUSION\Retry\retry($tries = 1, static function () use (&$invocations) {
             ++$invocations;
 
             return 5;
@@ -24,7 +25,7 @@ public function testFailingOnce()
         $invocations = 0;
         $failed = false;
 
-        $value = \ScriptFUSION\Retry\retry($tries = 2, function () use (&$invocations, &$failed) {
+        $value = \ScriptFUSION\Retry\retry($tries = 2, static function () use (&$invocations, &$failed) {
             ++$invocations;
 
             if (!$failed) {
@@ -45,7 +46,7 @@ public function testZeroTries()
     {
         $invocations = 0;
 
-        $value = \ScriptFUSION\Retry\retry($tries = 0, function () use (&$invocations) {
+        $value = \ScriptFUSION\Retry\retry($tries = 0, static function () use (&$invocations) {
             ++$invocations;
 
             return 5;
@@ -61,7 +62,7 @@ public function testFailingTooHard()
         $outerException = $innerException = null;
 
         try {
-            \ScriptFUSION\Retry\retry($tries = 2, function () use (&$invocations, &$innerException) {
+            \ScriptFUSION\Retry\retry($tries = 2, static function () use (&$invocations, &$innerException) {
                 ++$invocations;
 
                 throw $innerException = new \RuntimeException;
@@ -80,7 +81,7 @@ public function testErrorCallback()
         $outerException = $innerException = null;
 
         try {
-            \ScriptFUSION\Retry\retry($tries = 2, function () use (&$invocations, &$innerException) {
+            \ScriptFUSION\Retry\retry($tries = 2, static function () use (&$invocations, &$innerException) {
                 ++$invocations;
 
                 throw $innerException = new \RuntimeException;
@@ -97,21 +98,67 @@ public function testErrorCallback()
         self::assertSame($tries - 1, $errors);
     }
 
+    /**
+     * Tests that an error handler that returns false aborts retrying.
+     */
     public function testErrorCallbackHalt()
     {
         $invocations = 0;
 
+        \ScriptFUSION\Retry\retry($tries = 2, static function () use (&$invocations) {
+            ++$invocations;
+
+            throw new \RuntimeException;
+        }, static function () {
+            return false;
+        });
+
+        self::assertSame(1, $invocations);
+    }
+
+    /**
+     * Tests that a failed promise is retried.
+     */
+    public function testAsync()
+    {
+        $invocations = 0;
+        $failed = false;
+
+        $value = \Amp\Promise\wait(
+            \ScriptFUSION\Retry\retryAsync($tries = 2, static function () use (&$invocations, &$failed) {
+                ++$invocations;
+
+                if (!$failed) {
+                    $failed = true;
+
+                    throw new \RuntimeException;
+                }
+
+                return new Delayed(0, 'foo');
+            })
+        );
+
+        self::assertTrue($failed);
+        self::assertSame($tries, $invocations);
+        self::assertSame('foo', $value);
+    }
+
+    public function testFailingTooHardAsync()
+    {
+        $invocations = 0;
+        $outerException = $innerException = null;
+
         try {
-            \ScriptFUSION\Retry\retry($tries = 2, function () use (&$invocations) {
+            \ScriptFUSION\Retry\retryAsync($tries = 2, static function () use (&$invocations, &$innerException) {
                 ++$invocations;
 
-                throw new \RuntimeException;
-            }, function () {
-                return false;
+                throw $innerException = new \RuntimeException;
             });
-        } catch (FailingTooHardException $exception) {
+        } catch (FailingTooHardException $outerException) {
         }
 
-        self::assertSame(1, $invocations);
+        self::assertInstanceOf(FailingTooHardException::class, $outerException);
+        self::assertSame($innerException, $outerException->getPrevious());
+        self::assertSame($tries, $invocations);
     }
 }