From 8cbaf5423b4be22af80a6c350172bee3adc5d1a1 Mon Sep 17 00:00:00 2001
From: Demin Yin <demin.yin@glu.com>
Date: Thu, 6 Aug 2020 12:49:03 -0700
Subject: [PATCH] support doing exponential backoff in non-blocking mode in
 Swoole

---
 README.md                  |  2 ++
 composer.json              |  4 ++++
 src/ExponentialBackoff.php | 39 ++++++++++++++++++++++++++++++++++----
 3 files changed, 41 insertions(+), 4 deletions(-)

diff --git a/README.md b/README.md
index 18645e7..2671d87 100644
--- a/README.md
+++ b/README.md
@@ -8,6 +8,8 @@
 Exponential back-offs prevent overloading an unavailable service by doubling the timeout each iteration. This class uses
 an exponential back-off algorithm to calculate the timeout for the next request.
 
+This library allows doing exponential backoff in non-blocking mode in [Swoole](https://github.com/swoole/swoole-src).
+
 # Installation
 
 ```bash
diff --git a/composer.json b/composer.json
index c881298..e2e2dc7 100644
--- a/composer.json
+++ b/composer.json
@@ -9,8 +9,12 @@
     "require-dev": {
         "crowdstar/reflection": "~1.0.0",
         "phpunit/phpunit": "~7.0",
+        "swoole/ide-helper": "@dev",
         "squizlabs/php_codesniffer": ">=2.0"
     },
+    "suggest": {
+        "ext-swoole": "Allow to do exponential backoff in non-blocking mode in Swoole"
+    },
     "autoload": {
         "psr-4": {
             "CrowdStar\\Backoff\\": "src"
diff --git a/src/ExponentialBackoff.php b/src/ExponentialBackoff.php
index 76a7651..d275ecc 100644
--- a/src/ExponentialBackoff.php
+++ b/src/ExponentialBackoff.php
@@ -21,6 +21,7 @@
 namespace CrowdStar\Backoff;
 
 use Closure;
+use Swoole\Coroutine;
 
 /**
  * Class ExponentialBackoff
@@ -35,11 +36,21 @@ class ExponentialBackoff
     public const TYPE_MICROSECONDS = 1;
     public const TYPE_SECONDS      = 2;
 
+    protected const SAPI_DEFAULT = 1;
+    protected const SAPI_SWOOLE  = 2;
+
     /**
      * @var int
      */
     protected $type = self::TYPE_MICROSECONDS;
 
+    /**
+     * @var string
+     * @see \CrowdStar\Backoff\ExponentialBackoff::SAPI_DEFAULT
+     * @see \CrowdStar\Backoff\ExponentialBackoff::SAPI_SWOOLE
+     */
+    protected $sapi;
+
     /**
      * @var int
      */
@@ -55,8 +66,10 @@ class ExponentialBackoff
      */
     protected $retryCondition;
 
-    public function __construct(AbstractRetryCondition $retryCondition)
+    public function __construct(AbstractRetryCondition $retryCondition, int $sapi = 0)
     {
+        $this->sapi = $sapi ?: (extension_loaded('swoole') ? self::SAPI_SWOOLE : self::SAPI_DEFAULT);
+
         $this->setRetryCondition($retryCondition);
     }
 
@@ -177,10 +190,28 @@ protected function sleep(): self
     {
         switch ($this->getType()) {
             case self::TYPE_MICROSECONDS:
-                usleep($this->getTimeoutMicroseconds($this->getCurrentAttempts()));
+                $microSeconds = $this->getTimeoutMicroseconds($this->getCurrentAttempts());
+                switch ($this->sapi) {
+                    case self::SAPI_SWOOLE:
+                        // Minimum execution delay in Swoole is 1ms.
+                        Coroutine::sleep(max($microSeconds / 1000000, 0.001));
+                        break;
+                    default:
+                        usleep($microSeconds);
+                        break;
+                }
                 break;
             case self::TYPE_SECONDS:
-                usleep($this->getTimeoutSeconds($this->getCurrentAttempts()));
+                $seconds = $this->getTimeoutSeconds($this->getCurrentAttempts());
+                switch ($this->sapi) {
+                    case self::SAPI_SWOOLE:
+                        // Minimum execution delay in Swoole is 1ms.
+                        Coroutine::sleep(max($seconds, 0.001));
+                        break;
+                    default:
+                        sleep($seconds);
+                        break;
+                }
                 break;
             default:
                 throw new Exception("invalid backoff type '{$this->getType()}'");
@@ -194,7 +225,7 @@ protected function sleep(): self
      */
     protected function getTimeoutSeconds(int $iteration, int $initialTimeout = 1): int
     {
-        return ($this->getTimeoutMicroseconds($iteration, $initialTimeout * 1000000) / 1000000);
+        return (int) ($this->getTimeoutMicroseconds($iteration, $initialTimeout * 1000000) / 1000000);
     }
 
     /**