Implement custom FiberFactory interface

src/EventLoop/DefaultFiberFactory.php

@@ -0,0 +1,20 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Revolt\EventLoop;
+
+final class DefaultFiberFactory implements FiberFactory
+{
+    /**
+     * Creates a new fiber instance.
+     *
+     * @param callable $callable The callable to invoke when starting the fiber.
+     *
+     * @return \Fiber
+     */
+    public function create(callable $callback): \Fiber
+    {
+        return new \Fiber($callback);
+    }
+}

src/EventLoop/Driver/EvDriver.php

@@ -6,6 +6,7 @@
 
 namespace Revolt\EventLoop\Driver;
 
+use Revolt\EventLoop\FiberFactory;
 use Revolt\EventLoop\Internal\AbstractDriver;
 use Revolt\EventLoop\Internal\DriverCallback;
 use Revolt\EventLoop\Internal\SignalCallback;
@@ -38,9 +39,9 @@
     /** @var array<string, \EvSignal> */
     private array $signals = [];
 
-    public function __construct()
+    public function __construct(?FiberFactory $fiberFactory = null)
     {
-        parent::__construct();
+        parent::__construct($fiberFactory);
 
         $this->handle = new \EvLoop();
 
@@ -165,16 +166,16 @@
         $this->handle->nowUpdate();
         $now = $this->now();
 
         foreach ($callbacks as $callback) {
             if (!isset($this->events[$id = $callback->id])) {
                 if ($callback instanceof StreamReadableCallback) {
                     \assert(\is_resource($callback->stream));
 
                     $this->events[$id] = $this->handle->io($callback->stream, \Ev::READ, $this->ioCallback, $callback);
                 } elseif ($callback instanceof StreamWritableCallback) {
                     \assert(\is_resource($callback->stream));
 
                     $this->events[$id] = $this->handle->io(
                         $callback->stream,
                         \Ev::WRITE,
                         $this->ioCallback,

src/EventLoop/Driver/EventDriver.php

@@ -6,6 +6,7 @@
 
 namespace Revolt\EventLoop\Driver;
 
+use Revolt\EventLoop\FiberFactory;
 use Revolt\EventLoop\Internal\AbstractDriver;
 use Revolt\EventLoop\Internal\DriverCallback;
 use Revolt\EventLoop\Internal\SignalCallback;
@@ -34,9 +35,9 @@ public static function isSupported(): bool
     /** @var array<string, \Event> */
     private array $signals = [];
 
-    public function __construct()
+    public function __construct(?FiberFactory $fiberFactory = null)
     {
-        parent::__construct();
+        parent::__construct($fiberFactory);
 
         /** @psalm-suppress TooFewArguments https://github.com/JetBrains/phpstorm-stubs/pull/763 */
         $this->handle = new \EventBase();

src/EventLoop/Driver/StreamSelectDriver.php

@@ -6,6 +6,7 @@
 
 namespace Revolt\EventLoop\Driver;
 
+use Revolt\EventLoop\FiberFactory;
 use Revolt\EventLoop\Internal\AbstractDriver;
 use Revolt\EventLoop\Internal\DriverCallback;
 use Revolt\EventLoop\Internal\SignalCallback;
@@ -43,9 +44,9 @@ final class StreamSelectDriver extends AbstractDriver
 
     private bool $streamSelectIgnoreResult = false;
 
-    public function __construct()
+    public function __construct(?FiberFactory $fiberFactory = null)
     {
-        parent::__construct();
+        parent::__construct($fiberFactory);
 
         $this->signalQueue = new \SplQueue();
         $this->timerQueue = new TimerQueue();

src/EventLoop/Driver/UvDriver.php

@@ -4,6 +4,7 @@
 
 namespace Revolt\EventLoop\Driver;
 
+use Revolt\EventLoop\FiberFactory;
 use Revolt\EventLoop\Internal\AbstractDriver;
 use Revolt\EventLoop\Internal\DriverCallback;
 use Revolt\EventLoop\Internal\SignalCallback;
@@ -31,9 +32,9 @@ public static function isSupported(): bool
     private readonly \Closure $timerCallback;
     private readonly \Closure $signalCallback;
 
-    public function __construct()
+    public function __construct(?FiberFactory $fiberFactory = null)
     {
-        parent::__construct();
+        parent::__construct($fiberFactory);
 
         $this->handle = \uv_loop_new();
 

src/EventLoop/FiberFactory.php

@@ -0,0 +1,17 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Revolt\EventLoop;
+
+interface FiberFactory
+{
+    /**
+     * Creates a new fiber instance.
+     *
+     * @param callable $callable The callable to invoke when starting the fiber.
+     *
+     * @return \Fiber
+     */
+    public function create(callable $callback): \Fiber;
+}

src/EventLoop/FiberLocal.php

@@ -13,8 +13,8 @@
  */
 final class FiberLocal
 {
-    /** @var \Fiber|null Dummy fiber for {main} */
-    private static ?\Fiber $mainFiber = null;
+    /** @var object|null Dummy object for {main} */
+    private static ?object $dummyMain = null;
     private static ?\WeakMap $localStorage = null;
 
     public static function clear(): void
@@ -23,7 +23,7 @@ public static function clear(): void
             return;
         }
 
-        $fiber = \Fiber::getCurrent() ?? self::$mainFiber;
+        $fiber = \Fiber::getCurrent() ?? self::$dummyMain;
 
         if ($fiber === null) {
             return;
@@ -37,9 +37,8 @@ private static function getFiberStorage(): \WeakMap
         $fiber = \Fiber::getCurrent();
 
         if ($fiber === null) {
-            $fiber = self::$mainFiber ??= new \Fiber(static function (): void {
-                // dummy fiber for main, as we need some object for the WeakMap
-            });
+            $fiber = self::$dummyMain ??= new class () {
+            };
         }
 
         $localStorage = self::$localStorage ??= new \WeakMap();

src/EventLoop/Internal/AbstractDriver.php

@@ -5,7 +5,9 @@
 namespace Revolt\EventLoop\Internal;
 
 use Revolt\EventLoop\CallbackType;
+use Revolt\EventLoop\DefaultFiberFactory;
 use Revolt\EventLoop\Driver;
+use Revolt\EventLoop\FiberFactory;
 use Revolt\EventLoop\FiberLocal;
 use Revolt\EventLoop\InvalidCallbackError;
 use Revolt\EventLoop\Suspension;
@@ -58,13 +60,15 @@ abstract class AbstractDriver implements Driver
     /** @var \SplQueue<DriverCallback> */
     private readonly \SplQueue $callbackQueue;
 
+    private readonly FiberFactory $fiberFactory;
+
     private bool $idle = false;
     private bool $stopped = false;
 
     /** @var \WeakMap<object, \WeakReference<DriverSuspension>> */
     private \WeakMap $suspensions;
 
-    public function __construct()
+    public function __construct(?FiberFactory $fiberFactory = null)
     {
         if (\PHP_VERSION_ID < 80117 || \PHP_VERSION_ID >= 80200 && \PHP_VERSION_ID < 80204) {
             // PHP GC is broken on early 8.1 and 8.2 versions, see https://github.com/php/php-src/issues/10496
@@ -73,6 +77,7 @@ public function __construct()
                 throw new \Error('Your version of PHP is affected by serious garbage collector bugs related to fibers. Please upgrade to a newer version of PHP, i.e. >= 8.1.17 or => 8.2.4');
             }
         }
+        $this->fiberFactory = $fiberFactory ?? new DefaultFiberFactory();
 
         $this->suspensions = new \WeakMap();
 
@@ -402,7 +407,7 @@ final protected function error(\Closure $closure, \Throwable $exception): void
             return;
         }
 
-        $fiber = new \Fiber($this->errorCallback);
+        $fiber = $this->fiberFactory->create($this->errorCallback);
 
         /** @noinspection PhpUnhandledExceptionInspection */
         $fiber->start($this->errorHandler, $exception);
@@ -531,7 +536,7 @@ private function invokeInterrupt(): void
 
     private function createLoopFiber(): void
     {
-        $this->fiber = new \Fiber(function (): void {
+        $this->fiber = $this->fiberFactory->create(function (): void {
             $this->stopped = false;
 
             // Invoke microtasks if we have some
@@ -558,7 +563,7 @@ private function createLoopFiber(): void
 
     private function createCallbackFiber(): void
     {
-        $this->callbackFiber = new \Fiber(function (): void {
+        $this->callbackFiber = $this->fiberFactory->create(function (): void {
             do {
                 $this->invokeMicrotasks();
 

src/EventLoop/TracingFiberFactory.php

@@ -0,0 +1,63 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Revolt\EventLoop;
+
+use Countable;
+use IteratorAggregate;
+use Traversable;
+
+/**
+ * Fiber factory which collects all created fibers in a weak map.
+ *
+ * @implements IteratorAggregate<\Fiber, null>
+ */
+final class TracingFiberFactory implements FiberFactory, Countable, IteratorAggregate
+{
+    /**
+     * @var \WeakMap<\Fiber, null>
+     */
+    private readonly \WeakMap $map;
+
+    public function __construct(
+        private readonly FiberFactory $fiberFactory = new DefaultFiberFactory()
+    ) {
+        /** @var \WeakMap<\Fiber, null> */
+        $this->map = new \WeakMap();
+    }
+
+    /**
+     * Creates a new fiber instance.
+     *
+     * @param callable $callable The callable to invoke when starting the fiber.
+     *
+     * @return \Fiber
+     */
+    public function create(callable $callback): \Fiber
+    {
+        $f = $this->fiberFactory->create($callback);
+        $this->map[$f] = null;
+        return $f;
+    }
+
+    /**
+     * Returns the number of running fibers.
+     *
+     * @return int
+     */
+    public function count(): int
+    {
+        return $this->map->count();
+    }
+
+    /**
+     * Iterate over all fibers currently in scope.
+     *
+     * @return Traversable<\Fiber, null>
+     */
+    public function getIterator(): Traversable
+    {
+        return $this->map->getIterator();
+    }
+}

test/Driver/TracingFiberFactoryTest.php

@@ -0,0 +1,36 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Revolt\EventLoop\Driver;
+
+use Revolt\EventLoop\Driver;
+use Revolt\EventLoop\TracingFiberFactory;
+
+class TracingFiberFactoryTest extends StreamSelectDriverTest
+{
+    private static TracingFiberFactory $factory;
+    public function getFactory(): callable
+    {
+        self::$factory ??= new TracingFiberFactory();
+        return static function (): StreamSelectDriver {
+            return new StreamSelectDriver(self::$factory);
+        };
+    }
+
+    public function testNumberOfFibers(): void
+    {
+        self::assertEquals(2, self::$factory->count());
+        $this->start(static function (Driver $loop): void {
+            $loop->queue(static function () use ($loop) {
+                $suspension = $loop->getSuspension();
+                $loop->delay(1, $suspension->resume(...));
+                $suspension->suspend();
+            });
+            $loop->delay(0.5, function () {
+                self::assertEquals(3, self::$factory->count());
+            });
+        });
+        self::assertEquals(2, self::$factory->count());
+    }
+}