feat(async): throw if resource is closed while waiting

Signed-off-by: azjezz <azjezz@protonmail.com>

src/Psl/Async/Exception/ResourceClosedException.php

@@ -0,0 +1,9 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Psl\Async\Exception;
+
+final class ResourceClosedException extends RuntimeException
+{
+}

src/Psl/Async/await_readable.php

@@ -4,14 +4,19 @@
 
 namespace Psl\Async;
 
+use Psl\Async\Exception\ResourceClosedException;
 use Revolt\EventLoop;
+use Throwable;
+
+use function is_resource;
 
 /**
  * Wait for the given resource to become readable in a non-blocking way.
  *
  * @param resource|object $resource
  *
  * @throws Exception\TimeoutException If $timeout is non-null, and the operation timed-out.
+ * @throws Exception\ResourceClosedException If $resource was closed before it became readable.
  *
  * @codeCoverageIgnore
  */
@@ -36,6 +41,12 @@ function await_readable(mixed $resource, bool $reference = true, ?float $timeout
 
     try {
         $suspension->suspend();
+    } catch (Throwable $e) {
+        if (!is_resource($resource)) {
+            throw new ResourceClosedException('Resource was closed before it became readable.');
+        }
+
+        throw $e;
     } finally {
         Scheduler::cancel($watcher);
 

src/Psl/Async/await_writable.php

@@ -4,7 +4,9 @@
 
 namespace Psl\Async;
 
+use Psl\Async\Exception\ResourceClosedException;
 use Revolt\EventLoop;
+use Throwable;
 
 /**
  * Wait for the given resource to become writable in a non-blocking way.
@@ -36,6 +38,12 @@ function await_writable(mixed $resource, bool $reference = true, ?float $timeout
 
     try {
         $suspension->suspend();
+    } catch (Throwable $e) {
+        if (!is_resource($resource)) {
+            throw new ResourceClosedException('Resource was closed before it became writable.');
+        }
+
+        throw $e;
     } finally {
         Scheduler::cancel($watcher);
 

src/Psl/Async/main.php

@@ -4,35 +4,23 @@
 
 namespace Psl\Async;
 
-use Throwable;
-
 /**
  * Execute the given callable in an async context, then exit with returned exit code.
  *
  * If the callable returns an awaitable, the awaitable *MUST* resolve with an exit code.
  *
- * @param (callable(): int)|(callable(): Awaitable<int>) $callable
+ * @param (callable(): int)|(callable(): Awaitable<int>)|(callable(): never)|(callable(): Awaitable<never>) $callable
  *
  * @codeCoverageIgnore
  */
 function main(callable $callable): never
 {
-    $main = Scheduler::createSuspension();
-
-    Scheduler::defer(static function () use ($callable, $main): void {
-        try {
-            $exit_code = $callable();
-            $main->resume($exit_code);
-        } catch (Throwable $throwable) {
-            $main->throw($throwable);
-        }
-    });
+    later();
 
-    /** @var int|Awaitable<int> $return */
-    $return = $main->suspend();
-    if ($return instanceof Awaitable) {
-        $return = $return->await();
+    $result = $callable();
+    if ($result instanceof Awaitable) {
+        $result = $result->await();
     }
 
-    exit($return);
+    exit($result);
 }

src/Psl/IO/Internal/ResourceHandle.php

@@ -124,6 +124,10 @@ public function write(string $bytes, ?float $timeout = null): int
             Async\await_writable($this->resource, timeout: $timeout);
         } catch (Async\Exception\TimeoutException) {
             throw new Exception\TimeoutException('reached timeout while the handle is still not writable.');
+        } catch (Async\Exception\ResourceClosedException) {
+            $this->resource = null;
+
+            throw new Exception\AlreadyClosedException('Handle has already been closed.');
         }
 
         return $written + $this->writeImmediately($bytes);
@@ -215,6 +219,10 @@ public function read(?int $max_bytes = null, ?float $timeout = null): string
             Async\await_readable($this->resource, timeout: $timeout);
         } catch (Async\Exception\TimeoutException) {
             throw new Exception\TimeoutException('reached timeout while the handle is still not readable.');
+        } catch (Async\Exception\ResourceClosedException) {
+            $this->resource = null;
+
+            throw new Exception\AlreadyClosedException('Handle has already been closed.');
         }
 
         return $this->readImmediately($max_bytes);