Compatibility with iterable readable streams

Author: trowski

src/Driver/BlockingFile.php

@@ -3,13 +3,19 @@
 namespace Amp\File\Driver;
 
 use Amp\ByteStream\ClosedException;
+use Amp\ByteStream\ReadableStreamIteratorAggregate;
 use Amp\ByteStream\StreamException;
 use Amp\Cancellation;
 use Amp\DeferredFuture;
 use Amp\File\File;
 
-final class BlockingFile implements File
+/**
+ * @implements \IteratorAggregate<int, string>
+ */
+final class BlockingFile implements File, \IteratorAggregate
 {
+    use ReadableStreamIteratorAggregate;
+
     /** @var resource|null */
     private $handle;
     private string $path;

src/Driver/ParallelFile.php

@@ -3,6 +3,7 @@
 namespace Amp\File\Driver;
 
 use Amp\ByteStream\ClosedException;
+use Amp\ByteStream\ReadableStreamIteratorAggregate;
 use Amp\ByteStream\StreamException;
 use Amp\Cancellation;
 use Amp\DeferredFuture;
@@ -15,8 +16,13 @@
 use Revolt\EventLoop;
 use function Amp\async;
 
-final class ParallelFile implements File
+/**
+ * @implements \IteratorAggregate<int, string>
+ */
+final class ParallelFile implements File, \IteratorAggregate
 {
+    use ReadableStreamIteratorAggregate;
+
     private readonly Internal\FileWorker $worker;
 
     private ?int $id;

src/Driver/StatusCachingFile.php

@@ -2,11 +2,17 @@
 
 namespace Amp\File\Driver;
 
+use Amp\ByteStream\ReadableStreamIteratorAggregate;
 use Amp\Cancellation;
 use Amp\File\File;
 
-final class StatusCachingFile implements File
+/**
+ * @implements \IteratorAggregate<int, string>
+ */
+final class StatusCachingFile implements File, \IteratorAggregate
 {
+    use ReadableStreamIteratorAggregate;
+
     private readonly File $file;
 
     private readonly \Closure $invalidateCallback;

src/Internal/QueuedWritesFile.php

@@ -3,14 +3,21 @@
 namespace Amp\File\Internal;
 
 use Amp\ByteStream\ClosedException;
+use Amp\ByteStream\ReadableStreamIteratorAggregate;
+use Amp\Cancellation;
 use Amp\File\File;
 use Amp\File\PendingOperationError;
 use Amp\Future;
 use function Amp\async;
 
-/** @internal */
-abstract class QueuedWritesFile implements File
+/**
+ * @internal
+ * @implements \IteratorAggregate<int, string>
+ */
+abstract class QueuedWritesFile implements File, \IteratorAggregate
 {
+    use ReadableStreamIteratorAggregate;
+
     /** @var \SplQueue<Future<null>> */
     protected readonly \SplQueue $queue;
 
@@ -39,6 +46,11 @@ public function __destruct()
         async($this->close(...));
     }
 
+    abstract public function read(
+        ?Cancellation $cancellation = null,
+        int $length = self::DEFAULT_READ_LENGTH,
+    ): ?string;
+
     /**
      * @return Future<null>
      */
@@ -114,21 +126,12 @@ public function seek(int $position, int $whence = \SEEK_SET): int
             throw new PendingOperationError;
         }
 
-        switch ($whence) {
-            case self::SEEK_SET:
-                $this->position = $position;
-                break;
-            case self::SEEK_CUR:
-                $this->position += $position;
-                break;
-            case self::SEEK_END:
-                $this->position = $this->size + $position;
-                break;
-            default:
-                throw new \Error("Invalid whence parameter; SEEK_SET, SEEK_CUR or SEEK_END expected");
-        }
-
-        return $this->position;
+        return match ($whence) {
+            self::SEEK_SET => $this->position = $position,
+            self::SEEK_CUR => $this->position += $position,
+            self::SEEK_END => $this->position = $this->size + $position,
+            default => throw new \Error("Invalid whence parameter; SEEK_SET, SEEK_CUR or SEEK_END expected"),
+        };
     }
 
     public function tell(): int