Initial Commit

dependencies/amphp/byte-stream/lib/InputStreamChain.php

@@ -0,0 +1,44 @@
+<?php
+
+namespace WP_Ultimo\Dependencies\Amp\ByteStream;
+
+use WP_Ultimo\Dependencies\Amp\Promise;
+use WP_Ultimo\Dependencies\Amp\Success;
+use function WP_Ultimo\Dependencies\Amp\call;
+final class InputStreamChain implements InputStream
+{
+    /** @var InputStream[] */
+    private $streams;
+    /** @var bool */
+    private $reading = \false;
+    public function __construct(InputStream ...$streams)
+    {
+        $this->streams = $streams;
+    }
+    /** @inheritDoc */
+    public function read() : Promise
+    {
+        if ($this->reading) {
+            throw new PendingReadError();
+        }
+        if (!$this->streams) {
+            return new Success(null);
+        }
+        return call(function () {
+            $this->reading = \true;
+            try {
+                while ($this->streams) {
+                    $chunk = (yield $this->streams[0]->read());
+                    if ($chunk === null) {
+                        \array_shift($this->streams);
+                        continue;
+                    }
+                    return $chunk;
+                }
+                return null;
+            } finally {
+                $this->reading = \false;
+            }
+        });
+    }
+}