feat(async): introduce more async helper functions

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

examples/async/usleep.php

@@ -12,7 +12,7 @@
 Async\main(static function (): int {
     $start = time();
 
-    Async\concurrent([
+    Async\parallel([
         static fn() => Async\sleep(2.0),
         static fn() => Async\sleep(2.0),
         static fn() => Async\sleep(2.0),

examples/io/pipe.php

@@ -14,7 +14,7 @@
 
     $output = IO\output_handle();
 
-    Async\concurrent([
+    Async\parallel([
         static function() use($read, $output): void {
             $output->writeAll("< sleeping.\n");
 

examples/shell/concurrent.php

@@ -13,7 +13,7 @@
 Async\main(static function (): int {
     $start = time();
 
-    Async\concurrent([
+    Async\parallel([
         static fn() => Shell\execute(PHP_BINARY, ['-r', '$t = time(); while(time() < ($t+1)) { echo "."; }']),
         static fn() => Shell\execute(PHP_BINARY, ['-r', '$t = time(); while(time() < ($t+1)) { echo "."; }']),
         static fn() => Shell\execute(PHP_BINARY, ['-r', '$t = time(); while(time() < ($t+1)) { echo "."; }']),

examples/tcp/concurrent.php

@@ -14,7 +14,7 @@
 Async\main(static function (): int {
     $output = IO\output_handle();
 
-    Async\concurrent([
+    Async\parallel([
         'server' => static function () use ($output): void {
             $server = TCP\Server::create('localhost', 91337);
             $output->writeAll("< server is listening\n");

examples/unix/concurrent.php

@@ -24,7 +24,7 @@
 
     $output = IO\output_handle();
 
-    Async\concurrent([
+    Async\parallel([
         'server' => static function () use ($file, $output): void {
             $server = Unix\Server::create($file);
             $output->writeAll("< server is listening\n");

src/Psl/Async/all.php

@@ -10,7 +10,11 @@
 /**
  * Awaits all awaitables to complete concurrently.
  *
- * If one or more awaitables fail, all awaitables will be completed before throwing.
+ * If one awaitable fails, the exception will be thrown immediately, and the result of the callables will be ignored.
+ *
+ * If multiple awaitables failed at once, a {@see Exception\CompositeException} will be thrown.
+ *
+ * Once the awaitables have completed, an array containing the results will be returned preserving the original awaitables order.
  *
  * @template Tk of array-key
  * @template Tv
@@ -22,20 +26,35 @@
 function all(iterable $awaitables): array
 {
     $values = [];
-    $errors = [];
 
     // Awaitable::iterate() to throw the first error based on completion order instead of argument order
     foreach (Awaitable::iterate($awaitables) as $index => $awaitable) {
         try {
             $values[$index] = $awaitable->await();
         } catch (Throwable $throwable) {
-            $errors[] = $throwable;
-        }
-    }
+            $errors = [];
+            foreach ($awaitables as $original) {
+                if ($original === $awaitable) {
+                    continue;
+                }
 
-    if ($errors !== []) {
-        /** @psalm-suppress MissingThrowsDocblock */
-        throw $errors[0];
+                if (!$original->isComplete()) {
+                    $original->ignore();
+                } else {
+                    try {
+                        $original->await();
+                    } catch (Throwable $error) {
+                        $errors[] = $error;
+                    }
+                }
+            }
+
+            if ($errors === []) {
+                throw $throwable;
+            }
+
+            throw new Exception\CompositeException([$throwable, ...$errors], 'Multiple exceptions thrown while waiting.');
+        }
     }
 
     return Dict\map_with_key(

src/Psl/Async/any.php

@@ -27,7 +27,14 @@ function any(iterable $awaitables): mixed
     $errors = [];
     foreach (Awaitable::iterate($awaitables) as $first) {
         try {
-            return $first->await();
+            $result = $first->await();
+            foreach ($awaitables as $awaitable) {
+                if ($awaitable !== $first) {
+                    $awaitable->ignore();
+                }
+            }
+
+            return $result;
         } catch (Throwable $throwable) {
             $errors[] = $throwable;
         }

src/Psl/Async/first.php

@@ -18,12 +18,16 @@
  * @throws Psl\Exception\InvariantViolationException If $awaitables is empty.
  *
  * @return T
- *
- * @codeCoverageIgnore
  */
 function first(iterable $awaitables): mixed
 {
     foreach (Awaitable::iterate($awaitables) as $first) {
+        foreach ($awaitables as $awaitable) {
+            if ($awaitable !== $first) {
+                $awaitable->ignore();
+            }
+        }
+
         return $first->await();
     }
 

src/Psl/Async/parallel.php

@@ -0,0 +1,77 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Psl\Async;
+
+use Psl\Dict;
+
+/**
+ * Run the tasks iterable of functions in parallel, without waiting until the previous function has completed.
+ *
+ * If one tasks fails, the exception will be thrown immediately, and the result of the callables will be ignored.
+ *
+ * If multiple tasks failed at once, a {@see Exception\CompositeException} will be thrown.
+ *
+ * Once the tasks have completed, an array containing the results will be returned preserving the original awaitables order.
+ *
+ * <code>
+ * use Psl\Async;
+ *
+ * // execute `getOne()` and `getTwo()` functions in parallel.
+ *
+ * [$one, $two] = Async\parallel([
+ *   getOne(...),
+ *   getTwo(...),
+ * ]);
+ * </code>
+ *
+ * @note    {@see parallel()} is about kicking-off I/O tasks in parallel, not about parallel execution of code.
+ *          If your tasks do not use any timers or perform any I/O, they will actually be executed in series.
+ *
+ * <code>
+ * use Psl\Async;
+ *
+ * // the following runs in series.
+ *
+ * [$one, $two] = Async\parallel([
+ *   fn() => file_get_contents('path/to/file1.txt'),
+ *   fn() => file_get_contents('path/to/file2.txt'),
+ * ]);
+ * </code>
+ *
+ * @note    Use {@see reflect()} to continue the execution of other tasks when a task fails.
+ *
+ * <code>
+ * use Psl\Async;
+ *
+ * // execute `getOne()` and `getTwo()` functions in parallel.
+ * // if either one of the given tasks fails, the other will continue execution.
+ *
+ * [$one, $two] = Async\parallel([
+ *   Async\reflect(getOne(...)),
+ *   Async\reflect(getTwo(...)),
+ * ]);
+ * </code>
+ *
+ * @template Tk of array-key
+ * @template Tv
+ *
+ * @param iterable<Tk, (callable(): Tv)> $tasks
+ *
+ * @return array<Tk, Tv>
+ */
+function parallel(iterable $tasks): array
+{
+    $awaitables = Dict\map(
+        $tasks,
+        /**
+         * @param callable(): Tv $callable
+         *
+         * @return Awaitable<Tv>
+         */
+        static fn(callable $callable): Awaitable => run($callable),
+    );
+
+    return namespace\all($awaitables);
+}

src/Psl/Async/reflect.php

@@ -0,0 +1,28 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Psl\Async;
+
+use Closure;
+use Exception;
+use Psl\Result;
+
+/**
+ * Wraps the given task in another task that always completes with a {@see Result\Success},
+ * or {@see Result\Failure} if the callable throws an {@see Exception}.
+ *
+ * @template T
+ *
+ * @param (callable(): T) $task
+ *
+ * @return (Closure(): Result\ResultInterface<T>)
+ *
+ * @see Result\wrap()
+ *
+ * @pure
+ */
+function reflect(callable $task): Closure
+{
+    return static fn() => Result\wrap($task);
+}

src/Psl/Async/series.php

@@ -0,0 +1,32 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Psl\Async;
+
+use Psl\Dict;
+
+/**
+ * Run the functions in the tasks collection in series, each one running once the previous function has completed.
+ *
+ * If any functions in the series throws, no more functions are run, and the exception is immediately thrown.
+ *
+ * @template Tk of array-key
+ * @template Tv
+ *
+ * @param iterable<Tk, (callable(): Tv)> $tasks
+ *
+ * @return array<Tk, Tv>
+ */
+function series(iterable $tasks): array
+{
+    return Dict\map(
+        $tasks,
+        /**
+         * @param callable(): Tv $callable
+         *
+         * @return Tv
+         */
+        static fn(callable $callable): mixed => run($callable)->await(),
+    );
+}

src/Psl/Async/wrap.php

@@ -0,0 +1,24 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Psl\Async;
+
+use Psl\Result;
+
+/**
+ * Wraps the async function in an awaitable that completes with a {@see Result\Success},
+ * or {@see Result\Failure} if the task throws an {@see Exception}.
+ *
+ * @template T
+ *
+ * @param (callable(): T) $task
+ *
+ * @return Result\ResultInterface<T>
+ *
+ * @see reflect()
+ */
+function wrap(callable $task): Result\ResultInterface
+{
+    return run(reflect($task))->await();
+}

src/Psl/Internal/Loader.php

@@ -445,7 +445,10 @@ final class Loader
         'Psl\Trait\defined',
         'Psl\Async\main',
         'Psl\Async\run',
-        'Psl\Async\concurrent',
+        'Psl\Async\parallel',
+        'Psl\Async\reflect',
+        'Psl\Async\wrap',
+        'Psl\Async\series',
         'Psl\Async\await',
         'Psl\Async\any',
         'Psl\Async\all',

src/Psl/Shell/execute.php

@@ -164,7 +164,7 @@ static function (array $m) use (
     $stderr = new Stream\CloseReadHandle($pipes[2]);
 
     try {
-        [$stdout_content, $stderr_content] = Async\concurrent([
+        [$stdout_content, $stderr_content] = Async\parallel([
             static fn(): string => $stdout->readAll(timeout: $timeout),
             static fn(): string => $stderr->readAll(timeout: $timeout),
         ]);