New retry helpers

- `retry_timeout` - Repeats the callback until the answer is returned or timeout occurs
- `retry_count` - Repeats the callback until the answer is returned or the callback starts N times

composer.json

@@ -25,6 +25,7 @@
       "src/array_helpers.php",
       "src/common_helpers.php",
       "src/date_helpers.php",
+      "src/retry_helpers.php",
       "src/string_helpers.php"
     ]
   },

src/retry_helpers.php

@@ -0,0 +1,56 @@
+<?php declare(strict_types=1);
+
+namespace Acelot\Helpers;
+
+const SECONDS = 1000000;
+const MILLISECONDS = 1000;
+
+/**
+ * Repeats the callback until the answer is returned or timeout occurs.
+ *
+ * @param callable $callable Callback function
+ * @param int      $timeout  Microseconds
+ * @param int      $pause    Pause between repeats in microseconds
+ *
+ * @return mixed
+ * @throws \Throwable
+ */
+function retry_timeout(callable $callable, int $timeout, int $pause = 0)
+{
+    $start = microtime(true);
+
+    while (true) {
+        try {
+            return $callable();
+        } catch (\Throwable $e) {
+            if (microtime(true) - $start > ($timeout / SECONDS)) {
+                throw $e;
+            }
+            usleep($pause);
+        }
+    }
+}
+
+/**
+ * Repeats the callback until the answer is returned or the callback starts N times.
+ *
+ * @param callable $callable Callback function
+ * @param int      $count    Max number of tries
+ * @param int      $pause    Pause between repeats in microseconds
+ *
+ * @return mixed
+ * @throws \Throwable
+ */
+function retry_count(callable $callable, int $count, int $pause = 0)
+{
+    while (true) {
+        try {
+            return $callable();
+        } catch (\Throwable $e) {
+            if (--$count === 0) {
+                throw $e;
+            }
+            usleep($pause);
+        }
+    }
+}

tests/RetryHelpersTest.php

@@ -0,0 +1,68 @@
+<?php
+
+namespace Acelot\Helpers\Tests;
+
+use const Acelot\Helpers\MILLISECONDS;
+use function Acelot\Helpers\retry_count;
+use function Acelot\Helpers\retry_timeout;
+use PHPUnit\Framework\TestCase;
+
+class RetryHelpersTest extends TestCase
+{
+    public function testShouldFailOnTimeout()
+    {
+        $this->expectException(\Exception::class);
+
+        retry_timeout(function () {
+            throw new \Exception('test');
+        }, 1 * MILLISECONDS, 10);
+    }
+
+    public function testSuccessAfterOneHundredMilliSecond()
+    {
+        $i = 0;
+
+        try {
+            $start = microtime(true);
+
+            retry_timeout(
+                function () use (&$i) {
+                    if (++$i > 10) return true;
+                    throw new \Exception('test');
+                },
+                200 * MILLISECONDS,
+                10 * MILLISECONDS
+            );
+
+            $end = microtime(true) - $start;
+            $this->assertTrue($end > 0.1 && $end < 0.2);
+        } catch (\Exception $e) {
+            $this->fail();
+        }
+    }
+
+    public function testShouldFailOnMaxCount()
+    {
+        $this->expectException(\Exception::class);
+
+        retry_count(function () {
+            throw new \Exception('test');
+        }, 5, 10 * MILLISECONDS);
+    }
+
+    public function testSuccessAfterFiveTries()
+    {
+        $i = 0;
+
+        try {
+            $retries = retry_count(function () use (&$i) {
+                if (++$i === 5) return $i;
+                throw new \Exception('test');
+            }, 1 * MILLISECONDS, 10);
+
+            $this->assertEquals(5, $retries);
+        } catch (\Exception $e) {
+            $this->fail();
+        }
+    }
+}