running = true; try { while ($this->running) { if ($this->isEmpty()) { return; } $this->tick(); } } finally { $this->stop(); } } /** * @return bool True if no enabled and referenced watchers remain in the loop. */ private function isEmpty(): bool { foreach ($this->watchers as $watcher) { if ($watcher->enabled && $watcher->referenced) { return false; } } return true; } /** * Executes a single tick of the event loop. * * @return void */ private function tick() { if (empty($this->deferQueue)) { $this->deferQueue = $this->nextTickQueue; } else { $this->deferQueue = \array_merge($this->deferQueue, $this->nextTickQueue); } $this->nextTickQueue = []; $this->activate($this->enableQueue); $this->enableQueue = []; foreach ($this->deferQueue as $watcher) { if (!isset($this->deferQueue[$watcher->id])) { continue; // Watcher disabled by another defer watcher. } unset($this->watchers[$watcher->id], $this->deferQueue[$watcher->id]); try { /** @var mixed $result */ $result = ($watcher->callback)($watcher->id, $watcher->data); if ($result === null) { continue; } if ($result instanceof \Generator) { $result = new Coroutine($result); } if ($result instanceof Promise || $result instanceof ReactPromise) { rethrow($result); } } catch (\Throwable $exception) { $this->error($exception); } } /** @psalm-suppress RedundantCondition */ $this->dispatch(empty($this->nextTickQueue) && empty($this->enableQueue) && $this->running && !$this->isEmpty()); } /** * Activates (enables) all the given watchers. * * @param Watcher[] $watchers * * @return void */ abstract protected function activate(array $watchers); /** * Dispatches any pending read/write, timer, and signal events. * * @param bool $blocking * * @return void */ abstract protected function dispatch(bool $blocking); /** * Stop the event loop. * * When an event loop is stopped, it continues with its current tick and exits the loop afterwards. Multiple calls * to stop MUST be ignored and MUST NOT raise an exception. * * @return void */ public function stop() { $this->running = false; } /** * Defer the execution of a callback. * * The deferred callable MUST be executed before any other type of watcher in a tick. Order of enabling MUST be * preserved when executing the callbacks. * * The created watcher MUST immediately be marked as enabled, but only be activated (i.e. callback can be called) * right before the next tick. Callbacks of watchers MUST NOT be called in the tick they were enabled. * * @param callable (string $watcherId, mixed $data) $callback The callback to defer. The `$watcherId` will be * invalidated before the callback call. * @param mixed $data Arbitrary data given to the callback function as the `$data` parameter. * * @return string An unique identifier that can be used to cancel, enable or disable the watcher. */ public function defer(callable $callback, $data = null): string { /** @psalm-var Watcher $watcher */ $watcher = new Watcher; $watcher->type = Watcher::DEFER; $watcher->id = $this->nextId++; $watcher->callback = $callback; $watcher->data = $data; $this->watchers[$watcher->id] = $watcher; $this->nextTickQueue[$watcher->id] = $watcher; return $watcher->id; } /** * Delay the execution of a callback. * * The delay is a minimum and approximate, accuracy is not guaranteed. Order of calls MUST be determined by which * timers expire first, but timers with the same expiration time MAY be executed in any order. * * The created watcher MUST immediately be marked as enabled, but only be activated (i.e. callback can be called) * right before the next tick. Callbacks of watchers MUST NOT be called in the tick they were enabled. * * @param int $delay The amount of time, in milliseconds, to delay the execution for. * @param callable (string $watcherId, mixed $data) $callback The callback to delay. The `$watcherId` will be * invalidated before the callback call. * @param mixed $data Arbitrary data given to the callback function as the `$data` parameter. * * @return string An unique identifier that can be used to cancel, enable or disable the watcher. */ public function delay(int $delay, callable $callback, $data = null): string { if ($delay < 0) { throw new \Error("Delay must be greater than or equal to zero"); } /** @psalm-var Watcher $watcher */ $watcher = new Watcher; $watcher->type = Watcher::DELAY; $watcher->id = $this->nextId++; $watcher->callback = $callback; $watcher->value = $delay; $watcher->expiration = $this->now() + $delay; $watcher->data = $data; $this->watchers[$watcher->id] = $watcher; $this->enableQueue[$watcher->id] = $watcher; return $watcher->id; } /** * Repeatedly execute a callback. * * The interval between executions is a minimum and approximate, accuracy is not guaranteed. Order of calls MUST be * determined by which timers expire first, but timers with the same expiration time MAY be executed in any order. * The first execution is scheduled after the first interval period. * * The created watcher MUST immediately be marked as enabled, but only be activated (i.e. callback can be called) * right before the next tick. Callbacks of watchers MUST NOT be called in the tick they were enabled. * * @param int $interval The time interval, in milliseconds, to wait between executions. * @param callable (string $watcherId, mixed $data) $callback The callback to repeat. * @param mixed $data Arbitrary data given to the callback function as the `$data` parameter. * * @return string An unique identifier that can be used to cancel, enable or disable the watcher. */ public function repeat(int $interval, callable $callback, $data = null): string { if ($interval < 0) { throw new \Error("Interval must be greater than or equal to zero"); } /** @psalm-var Watcher $watcher */ $watcher = new Watcher; $watcher->type = Watcher::REPEAT; $watcher->id = $this->nextId++; $watcher->callback = $callback; $watcher->value = $interval; $watcher->expiration = $this->now() + $interval; $watcher->data = $data; $this->watchers[$watcher->id] = $watcher; $this->enableQueue[$watcher->id] = $watcher; return $watcher->id; } /** * Execute a callback when a stream resource becomes readable or is closed for reading. * * Warning: Closing resources locally, e.g. with `fclose`, might not invoke the callback. Be sure to `cancel` the * watcher when closing the resource locally. Drivers MAY choose to notify the user if there are watchers on invalid * resources, but are not required to, due to the high performance impact. Watchers on closed resources are * therefore undefined behavior. * * Multiple watchers on the same stream MAY be executed in any order. * * The created watcher MUST immediately be marked as enabled, but only be activated (i.e. callback can be called) * right before the next tick. Callbacks of watchers MUST NOT be called in the tick they were enabled. * * @param resource $stream The stream to monitor. * @param callable (string $watcherId, resource $stream, mixed $data) $callback The callback to execute. * @param mixed $data Arbitrary data given to the callback function as the `$data` parameter. * * @return string An unique identifier that can be used to cancel, enable or disable the watcher. */ public function onReadable($stream, callable $callback, $data = null): string { /** @psalm-var Watcher $watcher */ $watcher = new Watcher; $watcher->type = Watcher::READABLE; $watcher->id = $this->nextId++; $watcher->callback = $callback; $watcher->value = $stream; $watcher->data = $data; $this->watchers[$watcher->id] = $watcher; $this->enableQueue[$watcher->id] = $watcher; return $watcher->id; } /** * Execute a callback when a stream resource becomes writable or is closed for writing. * * Warning: Closing resources locally, e.g. with `fclose`, might not invoke the callback. Be sure to `cancel` the * watcher when closing the resource locally. Drivers MAY choose to notify the user if there are watchers on invalid * resources, but are not required to, due to the high performance impact. Watchers on closed resources are * therefore undefined behavior. * * Multiple watchers on the same stream MAY be executed in any order. * * The created watcher MUST immediately be marked as enabled, but only be activated (i.e. callback can be called) * right before the next tick. Callbacks of watchers MUST NOT be called in the tick they were enabled. * * @param resource $stream The stream to monitor. * @param callable (string $watcherId, resource $stream, mixed $data) $callback The callback to execute. * @param mixed $data Arbitrary data given to the callback function as the `$data` parameter. * * @return string An unique identifier that can be used to cancel, enable or disable the watcher. */ public function onWritable($stream, callable $callback, $data = null): string { /** @psalm-var Watcher $watcher */ $watcher = new Watcher; $watcher->type = Watcher::WRITABLE; $watcher->id = $this->nextId++; $watcher->callback = $callback; $watcher->value = $stream; $watcher->data = $data; $this->watchers[$watcher->id] = $watcher; $this->enableQueue[$watcher->id] = $watcher; return $watcher->id; } /** * Execute a callback when a signal is received. * * Warning: Installing the same signal on different instances of this interface is deemed undefined behavior. * Implementations MAY try to detect this, if possible, but are not required to. This is due to technical * limitations of the signals being registered globally per process. * * Multiple watchers on the same signal MAY be executed in any order. * * The created watcher MUST immediately be marked as enabled, but only be activated (i.e. callback can be called) * right before the next tick. Callbacks of watchers MUST NOT be called in the tick they were enabled. * * @param int $signo The signal number to monitor. * @param callable (string $watcherId, int $signo, mixed $data) $callback The callback to execute. * @param mixed $data Arbitrary data given to the callback function as the $data parameter. * * @return string An unique identifier that can be used to cancel, enable or disable the watcher. * * @throws UnsupportedFeatureException If signal handling is not supported. */ public function onSignal(int $signo, callable $callback, $data = null): string { /** @psalm-var Watcher $watcher */ $watcher = new Watcher; $watcher->type = Watcher::SIGNAL; $watcher->id = $this->nextId++; $watcher->callback = $callback; $watcher->value = $signo; $watcher->data = $data; $this->watchers[$watcher->id] = $watcher; $this->enableQueue[$watcher->id] = $watcher; return $watcher->id; } /** * Enable a watcher to be active starting in the next tick. * * Watchers MUST immediately be marked as enabled, but only be activated (i.e. callbacks can be called) right before * the next tick. Callbacks of watchers MUST NOT be called in the tick they were enabled. * * @param string $watcherId The watcher identifier. * * @return void * * @throws InvalidWatcherError If the watcher identifier is invalid. */ public function enable(string $watcherId) { if (!isset($this->watchers[$watcherId])) { throw new InvalidWatcherError($watcherId, "Cannot enable an invalid watcher identifier: '{$watcherId}'"); } $watcher = $this->watchers[$watcherId]; if ($watcher->enabled) { return; // Watcher already enabled. } $watcher->enabled = true; switch ($watcher->type) { case Watcher::DEFER: $this->nextTickQueue[$watcher->id] = $watcher; break; case Watcher::REPEAT: case Watcher::DELAY: \assert(\is_int($watcher->value)); $watcher->expiration = $this->now() + $watcher->value; $this->enableQueue[$watcher->id] = $watcher; break; default: $this->enableQueue[$watcher->id] = $watcher; break; } } /** * Cancel a watcher. * * This will detach the event loop from all resources that are associated to the watcher. After this operation the * watcher is permanently invalid. Calling this function MUST NOT fail, even if passed an invalid watcher. * * @param string $watcherId The watcher identifier. * * @return void */ public function cancel(string $watcherId) { $this->disable($watcherId); unset($this->watchers[$watcherId]); } /** * Disable a watcher immediately. * * A watcher MUST be disabled immediately, e.g. if a defer watcher disables a later defer watcher, the second defer * watcher isn't executed in this tick. * * Disabling a watcher MUST NOT invalidate the watcher. Calling this function MUST NOT fail, even if passed an * invalid watcher. * * @param string $watcherId The watcher identifier. * * @return void */ public function disable(string $watcherId) { if (!isset($this->watchers[$watcherId])) { return; } $watcher = $this->watchers[$watcherId]; if (!$watcher->enabled) { return; // Watcher already disabled. } $watcher->enabled = false; $id = $watcher->id; switch ($watcher->type) { case Watcher::DEFER: if (isset($this->nextTickQueue[$id])) { // Watcher was only queued to be enabled. unset($this->nextTickQueue[$id]); } else { unset($this->deferQueue[$id]); } break; default: if (isset($this->enableQueue[$id])) { // Watcher was only queued to be enabled. unset($this->enableQueue[$id]); } else { $this->deactivate($watcher); } break; } } /** * Deactivates (disables) the given watcher. * * @param Watcher $watcher * * @return void */ abstract protected function deactivate(Watcher $watcher); /** * Reference a watcher. * * This will keep the event loop alive whilst the watcher is still being monitored. Watchers have this state by * default. * * @param string $watcherId The watcher identifier. * * @return void * * @throws InvalidWatcherError If the watcher identifier is invalid. */ public function reference(string $watcherId) { if (!isset($this->watchers[$watcherId])) { throw new InvalidWatcherError($watcherId, "Cannot reference an invalid watcher identifier: '{$watcherId}'"); } $this->watchers[$watcherId]->referenced = true; } /** * Unreference a watcher. * * The event loop should exit the run method when only unreferenced watchers are still being monitored. Watchers * are all referenced by default. * * @param string $watcherId The watcher identifier. * * @return void */ public function unreference(string $watcherId) { if (!isset($this->watchers[$watcherId])) { return; } $this->watchers[$watcherId]->referenced = false; } /** * Stores information in the loop bound registry. * * Stored information is package private. Packages MUST NOT retrieve the stored state of other packages. Packages * MUST use their namespace as prefix for keys. They may do so by using `SomeClass::class` as key. * * If packages want to expose loop bound state to consumers other than the package, they SHOULD provide a dedicated * interface for that purpose instead of sharing the storage key. * * @param string $key The namespaced storage key. * @param mixed $value The value to be stored. * * @return void */ final public function setState(string $key, $value) { if ($value === null) { unset($this->registry[$key]); } else { $this->registry[$key] = $value; } } /** * Gets information stored bound to the loop. * * Stored information is package private. Packages MUST NOT retrieve the stored state of other packages. Packages * MUST use their namespace as prefix for keys. They may do so by using `SomeClass::class` as key. * * If packages want to expose loop bound state to consumers other than the package, they SHOULD provide a dedicated * interface for that purpose instead of sharing the storage key. * * @param string $key The namespaced storage key. * * @return mixed The previously stored value or `null` if it doesn't exist. */ final public function getState(string $key) { return isset($this->registry[$key]) ? $this->registry[$key] : null; } /** * Set a callback to be executed when an error occurs. * * The callback receives the error as the first and only parameter. The return value of the callback gets ignored. * If it can't handle the error, it MUST throw the error. Errors thrown by the callback or during its invocation * MUST be thrown into the `run` loop and stop the driver. * * Subsequent calls to this method will overwrite the previous handler. * * @param callable(\Throwable $error):void|null $callback The callback to execute. `null` will clear the * current handler. * * @return callable(\Throwable $error):void|null The previous handler, `null` if there was none. */ public function setErrorHandler(callable $callback = null) { $previous = $this->errorHandler; $this->errorHandler = $callback; return $previous; } /** * Invokes the error handler with the given exception. * * @param \Throwable $exception The exception thrown from a watcher callback. * * @return void * @throws \Throwable If no error handler has been set. */ protected function error(\Throwable $exception) { if ($this->errorHandler === null) { throw $exception; } ($this->errorHandler)($exception); } /** * Returns the current loop time in millisecond increments. Note this value does not necessarily correlate to * wall-clock time, rather the value returned is meant to be used in relative comparisons to prior values returned * by this method (intervals, expiration calculations, etc.) and is only updated once per loop tick. * * Extending classes should override this function to return a value cached once per loop tick. * * @return int */ public function now(): int { return (int) (\microtime(true) * self::MILLISEC_PER_SEC); } /** * Get the underlying loop handle. * * Example: the `uv_loop` resource for `libuv` or the `EvLoop` object for `libev` or `null` for a native driver. * * Note: This function is *not* exposed in the `Loop` class. Users shall access it directly on the respective loop * instance. * * @return null|object|resource The loop handle the event loop operates on. `null` if there is none. */ abstract public function getHandle(); /** * Returns the same array of data as getInfo(). * * @return array */ public function __debugInfo() { // @codeCoverageIgnoreStart return $this->getInfo(); // @codeCoverageIgnoreEnd } /** * Retrieve an associative array of information about the event loop driver. * * The returned array MUST contain the following data describing the driver's currently registered watchers: * * [ * "defer" => ["enabled" => int, "disabled" => int], * "delay" => ["enabled" => int, "disabled" => int], * "repeat" => ["enabled" => int, "disabled" => int], * "on_readable" => ["enabled" => int, "disabled" => int], * "on_writable" => ["enabled" => int, "disabled" => int], * "on_signal" => ["enabled" => int, "disabled" => int], * "enabled_watchers" => ["referenced" => int, "unreferenced" => int], * "running" => bool * ]; * * Implementations MAY optionally add more information in the array but at minimum the above `key => value` format * MUST always be provided. * * @return array Statistics about the loop in the described format. */ public function getInfo(): array { $watchers = [ "referenced" => 0, "unreferenced" => 0, ]; $defer = $delay = $repeat = $onReadable = $onWritable = $onSignal = [ "enabled" => 0, "disabled" => 0, ]; foreach ($this->watchers as $watcher) { switch ($watcher->type) { case Watcher::READABLE: $array = &$onReadable; break; case Watcher::WRITABLE: $array = &$onWritable; break; case Watcher::SIGNAL: $array = &$onSignal; break; case Watcher::DEFER: $array = &$defer; break; case Watcher::DELAY: $array = &$delay; break; case Watcher::REPEAT: $array = &$repeat; break; default: // @codeCoverageIgnoreStart throw new \Error("Unknown watcher type"); // @codeCoverageIgnoreEnd } if ($watcher->enabled) { ++$array["enabled"]; if ($watcher->referenced) { ++$watchers["referenced"]; } else { ++$watchers["unreferenced"]; } } else { ++$array["disabled"]; } } return [ "enabled_watchers" => $watchers, "defer" => $defer, "delay" => $delay, "repeat" => $repeat, "on_readable" => $onReadable, "on_writable" => $onWritable, "on_signal" => $onSignal, "running" => (bool) $this->running, ]; } }