commit a296fd61aac25297e0c17d9d2ec2adb96fd3aa32
Author: Joop Schilder <j.n.m.schilder@st.hanze.nl>
Date:   Wed Jan 16 01:10:54 2019 +0100

    Initial commit

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..16b9744
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,5 @@
+/vendor/
+/composer.lock
+/.idea/
+/.phpstorm/
+/.vscode/
\ No newline at end of file
diff --git a/bin/app.php b/bin/app.php
new file mode 100755
index 0000000..6f1a672
--- /dev/null
+++ b/bin/app.php
@@ -0,0 +1,35 @@
+#!/usr/bin/php
+<?php
+
+require_once __DIR__ . '/../vendor/autoload.php';
+
+
+// Create a function we want to run asynchronously
+$process = function ($i) {
+	$delayMicroseconds = (10 - $i) * 1000000;
+	usleep($delayMicroseconds);
+
+	return getmypid();
+};
+
+
+// Execute the functions asynchronously - each returning a Promise
+$promises = [];
+foreach (range(0, 10) as $i)
+	$promises[] = Asynchronous::run($process, $i);
+
+
+// Wait for all promises to resolve
+while (count($promises) > 0) {
+	foreach ($promises as $index => $promise) {
+		if ($promise->isResolved() && !$promise->isEmpty()) {
+			print("Response retrieved: " . $promise->getValue() . PHP_EOL);
+			unset($promises[$index]);
+		}
+	}
+}
+
+
+exit(0);
+
+
diff --git a/composer.json b/composer.json
new file mode 100644
index 0000000..cfcb8f7
--- /dev/null
+++ b/composer.json
@@ -0,0 +1,19 @@
+{
+    "name": "joop/php-async",
+    "authors": [
+        {
+            "name": "Joop Schilder",
+            "email": "j.n.m.schilder@st.hanze.nl"
+        }
+    ],
+    "autoload": {
+        "psr-0": {
+            "": ["src"]
+        }
+    },
+    "require": {
+        "ext-pcntl": "*",
+        "ext-curl": "*",
+        "ext-sysvshm": "*"
+    }
+}
diff --git a/src/Asynchronous.php b/src/Asynchronous.php
new file mode 100644
index 0000000..3798762
--- /dev/null
+++ b/src/Asynchronous.php
@@ -0,0 +1,127 @@
+<?php
+
+
+/**
+ * Class Asynchronous
+ */
+class Asynchronous
+{
+
+	private static $instance;
+
+	/** @var bool */
+	private $isChild = false;
+
+	private static $key = 0;
+
+	/** @var int[] */
+	private $children = [];
+
+	/** @var resource */
+	private $shm;
+
+	/** @var int */
+	private $shmKey;
+
+	/** @var string */
+	private $tempFile;
+
+	/**
+	 * Asynchronous constructor.
+	 */
+	private function __construct()
+	{
+		$this->tempFile = tempnam(__DIR__ . '/../temp', 'PHP');
+		$this->shmKey = ftok($this->tempFile, 'a');
+		Promise::_setShmKey($this->shmKey);
+		$this->attach();
+	}
+
+	/**
+	 * @return $this
+	 */
+	private function attach()
+	{
+		$this->shm = shm_attach($this->shmKey);
+
+		return $this;
+	}
+
+	/**
+	 * @return Asynchronous
+	 */
+	private static function getInstance()
+	{
+		if (is_null(self::$instance))
+			self::$instance = new static();
+
+		return self::$instance;
+	}
+
+
+	/**
+	 * @param callable $function
+	 * @param mixed ...$parameters
+	 * @return Promise|null;
+	 */
+	public static function run(callable $function, ...$parameters)
+	{
+		$instance = self::getInstance();
+		$pid = pcntl_fork();
+
+		if ($pid === false)
+			return null;
+
+		$key = self::generatePromiseKey();
+
+		if ($pid > 0) {
+			$instance->children[] = $pid;
+
+			return new Promise($key);
+		}
+
+		$instance->isChild = true;
+		$instance->attach();
+		try {
+			$response = call_user_func($function, ...$parameters);
+			shm_put_var($instance->shm, $key, $response ?? Promise::RESPONSE_NONE);
+			exit(0);
+		} catch (Throwable $throwable) {
+			exit(1);
+		}
+
+
+	}
+
+	/**
+	 * @return int
+	 */
+	private static function generatePromiseKey()
+	{
+		$promiseKey = self::$key;
+		self::$key++;
+		if (self::$key > 9999999)
+			self::$key = 0;
+
+		return $promiseKey;
+	}
+
+
+	/**
+	 *
+	 */
+	public function __destruct()
+	{
+		if ($this->isChild)
+			return;
+
+		while (count($this->children) > 0) {
+			pcntl_wait($status);
+			array_shift($this->children);
+		}
+		shm_remove($this->shm);
+		shm_detach($this->shm);
+		unlink($this->tempFile);
+	}
+
+}
\ No newline at end of file
diff --git a/src/Promise.php b/src/Promise.php
new file mode 100644
index 0000000..ba4be81
--- /dev/null
+++ b/src/Promise.php
@@ -0,0 +1,72 @@
+<?php
+
+
+class Promise
+{
+	public const RESPONSE_NONE = '__PROMISE_RESPONSE_NONE__';
+
+	private $shm;
+	private $key;
+	private $value;
+
+	/** @var int */
+	private static $shmKey;
+
+	public static function _setShmKey(int $shmKey)
+	{
+		self::$shmKey = $shmKey;
+	}
+
+	/**
+	 * Promise constructor.
+	 * @param int $key
+	 */
+	public function __construct(int $key)
+	{
+		$this->key = $key;
+		$this->value = null;
+		$this->shm = shm_attach(self::$shmKey);
+	}
+
+	/**
+	 * @return bool
+	 */
+	public function isResolved()
+	{
+		return shm_has_var($this->shm, $this->key);
+	}
+
+	/**
+	 * @return bool
+	 */
+	public function isEmpty()
+	{
+		return $this->getValue() === self::RESPONSE_NONE;
+	}
+
+	/**
+	 * @return mixed|null
+	 */
+	public function getValue()
+	{
+		return $this->isResolved() ? $this->resolve()->value : null;
+	}
+
+	/**
+	 * @return $this
+	 */
+	public function resolve()
+	{
+		while (!$this->isResolved())
+			usleep(1000); // 1ms
+
+		$this->value = shm_get_var($this->shm, $this->key);
+		return $this;
+	}
+
+	public function __destruct()
+	{
+		if (is_resource($this->shm))
+			shm_detach($this->shm);
+	}
+}
\ No newline at end of file