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keluniktrowski
kelunik
and
trowski
authored
Implement fiber local storage (#40)
Co-authored-by: Aaron Piotrowski <[email protected]>
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8 files changed

+336
-1
lines changed

8 files changed

+336
-1
lines changed

‎examples/fiber-local-automatic.php

+47
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@@ -0,0 +1,47 @@
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<?php
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use Revolt\EventLoop;
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use Revolt\EventLoop\FiberLocal;
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require __DIR__ . '/../vendor/autoload.php';
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/**
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* This logger uses {@see FiberLocal} to automatically log a transaction identifier bound to the current fiber.
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*
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* This might be used to log the current URL, authenticated user, or request identifier in an HTTP server.
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*/
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final class Logger
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{
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private int $nextId = 1;
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private FiberLocal $transactionId;
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public function __construct()
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{
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$this->transactionId = new FiberLocal(fn () => $this->nextId++);
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}
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public function log(string $message): void
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{
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echo $this->transactionId->get() . ': ' . $message . PHP_EOL;
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}
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}
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$logger = new Logger();
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EventLoop::delay(1, static function () use ($logger) {
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$logger->log('Initializing...');
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$suspension = EventLoop::getSuspension();
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EventLoop::delay(1, static fn () => $suspension->resume());
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$suspension->suspend();
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$logger->log('Done.');
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});
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$logger->log('Initializing...');
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$suspension = EventLoop::getSuspension();
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EventLoop::delay(3, static fn () => $suspension->resume());
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$suspension->suspend();
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$logger->log('Done.');

‎examples/fiber-local-manual.php

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@@ -0,0 +1,54 @@
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<?php
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use Revolt\EventLoop;
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use Revolt\EventLoop\FiberLocal;
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require __DIR__ . '/../vendor/autoload.php';
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/**
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* This logger uses {@see FiberLocal} to automatically log a transaction identifier bound to the current fiber.
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*
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* This might be used to log the current URL, authenticated user, or request identifier in an HTTP server.
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*/
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final class Logger
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{
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private FiberLocal $transactionId;
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public function __construct()
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{
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$this->transactionId = new FiberLocal(fn () => null);
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}
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public function setTransactionId(int $transactionId): void
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{
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$this->transactionId->set($transactionId);
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}
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public function log(string $message): void
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{
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echo $this->transactionId->get() . ': ' . $message . PHP_EOL;
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}
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}
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$logger = new Logger();
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$logger->setTransactionId(1);
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EventLoop::delay(1, static function () use ($logger) {
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$logger->setTransactionId(2);
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$logger->log('Initializing...');
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$suspension = EventLoop::getSuspension();
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EventLoop::delay(1, static fn () => $suspension->resume());
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$suspension->suspend();
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$logger->log('Done.');
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});
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$logger->log('Initializing...');
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$suspension = EventLoop::getSuspension();
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EventLoop::delay(3, static fn () => $suspension->resume());
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$suspension->suspend();
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$logger->log('Done.');

‎psalm.xml

+6
Original file line numberDiff line numberDiff line change
@@ -16,6 +16,12 @@
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</projectFiles>
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<issueHandlers>
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<DuplicateClass>
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<errorLevel type="suppress">
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<directory name="examples" />
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</errorLevel>
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</DuplicateClass>
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<StringIncrement>
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<errorLevel type="suppress">
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<directory name="examples"/>

‎src/EventLoop/Driver.php

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Original file line numberDiff line numberDiff line change
@@ -2,6 +2,10 @@
22

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namespace Revolt\EventLoop;
44

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/**
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* The driver MUST run in its own fiber and execute callbacks in a separate fiber. If fibers are reused, the driver
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* needs to call {@see FiberLocal::clear()} after running the callback.
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*/
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interface Driver
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{
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/**

‎src/EventLoop/FiberLocal.php

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<?php
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namespace Revolt\EventLoop;
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/**
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* Fiber local storage.
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*
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* Each instance stores data separately for each fiber. Usage examples include contextual logging data.
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*
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* @template T
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*/
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final class FiberLocal
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{
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/** @var \Fiber|null Dummy fiber for {main} */
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private static ?\Fiber $mainFiber = null;
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private static ?\WeakMap $localStorage = null;
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public static function clear(): void
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{
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if (self::$localStorage === null) {
21+
return;
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}
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$fiber = \Fiber::getCurrent() ?? self::$mainFiber;
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if ($fiber === null) {
27+
return;
28+
}
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unset(self::$localStorage[$fiber]);
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}
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private static function getFiberStorage(): \WeakMap
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{
35+
$fiber = \Fiber::getCurrent();
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if ($fiber === null) {
38+
$fiber = self::$mainFiber ??= new \Fiber(static function () {
39+
// dummy fiber for main, as we need some object for the WeakMap
40+
});
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}
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$localStorage = self::$localStorage ??= new \WeakMap();
44+
return $localStorage[$fiber] ??= new \WeakMap();
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}
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/**
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* @param \Closure():T $initializer
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*/
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public function __construct(private \Closure $initializer)
51+
{
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}
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/**
55+
* @param T $value
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*
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* @return void
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*/
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public function set(mixed $value): void
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{
61+
self::getFiberStorage()[$this] = [$value];
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}
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/**
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* @return T
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*/
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public function get(): mixed
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{
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$fiberStorage = self::getFiberStorage();
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if (!isset($fiberStorage[$this])) {
72+
$fiberStorage[$this] = [($this->initializer)()];
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}
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return $fiberStorage[$this][0];
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}
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}

‎src/EventLoop/Internal/AbstractDriver.php

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Original file line numberDiff line numberDiff line change
@@ -3,6 +3,7 @@
33
namespace Revolt\EventLoop\Internal;
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55
use Revolt\EventLoop\Driver;
6+
use Revolt\EventLoop\FiberLocal;
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use Revolt\EventLoop\InvalidCallbackError;
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use Revolt\EventLoop\Suspension;
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use Revolt\EventLoop\UncaughtThrowable;
@@ -444,6 +445,8 @@ private function invokeMicrotasks(): void
444445
$callback(...$args);
445446
} catch (\Throwable $exception) {
446447
$this->error($callback, $exception);
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} finally {
449+
FiberLocal::clear();
447450
}
448451

449452
unset($callback, $args);
@@ -615,6 +618,8 @@ private function createCallbackFiber(): void
615618
}
616619
} catch (\Throwable $exception) {
617620
$this->error($callback->closure, $exception);
621+
} finally {
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FiberLocal::clear();
618623
}
619624

620625
unset($callback);

‎test/EventLoopTest.php

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Original file line numberDiff line numberDiff line change
@@ -218,7 +218,6 @@ public function testSuspensionThrowingErrorViaInterrupt(): void
218218
$suspension = EventLoop::getSuspension();
219219
$error = new \Error("Test error");
220220
EventLoop::queue(static fn () => throw $error);
221-
EventLoop::defer(static fn () => $suspension->resume("Value"));
222221
try {
223222
$suspension->suspend();
224223
self::fail("Error was not thrown");

‎test/FiberLocalTest.php

+143
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<?php
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namespace Revolt\EventLoop;
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use PHPUnit\Framework\TestCase;
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use Revolt\EventLoop;
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class FiberLocalTest extends TestCase
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{
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public function test(): void
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{
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$fiberLocal = new FiberLocal(fn () => 'initial');
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self::assertSame('initial', $fiberLocal->get());
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$suspension = EventLoop::getSuspension();
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EventLoop::queue(static function () use ($suspension, $fiberLocal) {
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$suspension->resume($fiberLocal->get());
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});
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self::assertSame('initial', $suspension->suspend());
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EventLoop::queue(static function () use ($suspension, $fiberLocal) {
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$fiberLocal->set('fiber');
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$suspension->resume($fiberLocal->get());
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});
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self::assertSame('fiber', $suspension->suspend());
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self::assertSame('initial', $fiberLocal->get());
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}
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public function testManualClear(): void
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{
36+
$fiberLocal = new FiberLocal(fn () => 'initial');
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self::assertSame('initial', $fiberLocal->get());
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$suspension = EventLoop::getSuspension();
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EventLoop::queue(static function () use ($suspension, $fiberLocal, &$fiberSuspension) {
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$fiberSuspension = EventLoop::getSuspension();
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$fiberLocal->set('fiber');
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$suspension->resume($fiberLocal->get());
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$fiberSuspension->suspend();
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$suspension->resume($fiberLocal->get());
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$fiberSuspension->suspend();
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FiberLocal::clear();
53+
$suspension->resume($fiberLocal->get());
54+
});
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self::assertSame('fiber', $suspension->suspend());
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self::assertSame('initial', $fiberLocal->get());
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FiberLocal::clear();
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$fiberSuspension->resume();
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self::assertSame('fiber', $suspension->suspend());
64+
self::assertSame('initial', $fiberLocal->get());
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$fiberSuspension->resume();
67+
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self::assertSame('initial', $suspension->suspend());
69+
self::assertSame('initial', $fiberLocal->get());
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}
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public function testCallbackFiberClear(): void
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{
74+
$fiberLocal = new FiberLocal(fn () => 'initial');
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$suspension = EventLoop::getSuspension();
77+
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EventLoop::defer(static function () use ($fiberLocal, &$fiber1) {
79+
$fiberLocal->set('fiber');
80+
$fiber1 = \Fiber::getCurrent();
81+
});
82+
83+
EventLoop::defer(static function () use ($suspension, $fiberLocal, &$fiber2) {
84+
$fiber2 = \Fiber::getCurrent();
85+
$suspension->resume($fiberLocal->get());
86+
});
87+
88+
self::assertSame('initial', $suspension->suspend());
89+
self::assertSame($fiber1, $fiber2);
90+
}
91+
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public function testMicrotaskFiberClear(): void
93+
{
94+
$fiberLocal = new FiberLocal(fn () => 'initial');
95+
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$suspension = EventLoop::getSuspension();
97+
98+
EventLoop::queue(static function () use ($fiberLocal, &$fiber1) {
99+
$fiberLocal->set('fiber');
100+
$fiber1 = \Fiber::getCurrent();
101+
});
102+
103+
EventLoop::queue(static function () use ($suspension, $fiberLocal, &$fiber2) {
104+
$fiber2 = \Fiber::getCurrent();
105+
$suspension->resume($fiberLocal->get());
106+
});
107+
108+
self::assertSame('initial', $suspension->suspend());
109+
self::assertSame($fiber1, $fiber2);
110+
}
111+
112+
public function testMicrotaskAfterSuspension(): void
113+
{
114+
$fiberLocal = new FiberLocal(fn () => 'initial');
115+
116+
$mainSuspension = EventLoop::getSuspension();
117+
118+
EventLoop::queue(static function () use ($fiberLocal, $mainSuspension) {
119+
$fiberLocal->set('fiber');
120+
121+
$suspension = EventLoop::getSuspension();
122+
EventLoop::defer(static fn () => $suspension->resume());
123+
$suspension->suspend();
124+
125+
$mainSuspension->resume($fiberLocal->get());
126+
});
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128+
self::assertSame('fiber', $mainSuspension->suspend());
129+
}
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131+
public function testInitializeWithNull(): void
132+
{
133+
$invoked = 0;
134+
$fiberLocal = new FiberLocal(function () use (&$invoked) {
135+
++$invoked;
136+
return null;
137+
});
138+
139+
self::assertNull($fiberLocal->get());
140+
self::assertNull($fiberLocal->get());
141+
self::assertSame(1, $invoked);
142+
}
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}

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