Simplify closing stream

Author: clue

src/UnwrapReadableStream.php

@@ -30,13 +30,6 @@ public function __construct(PromiseInterface $promise)
 
         // TODO: support backpressure
 
-        // try to cancel promise once the stream closes
-        if ($promise instanceof CancellablePromiseInterface) {
-            $out->on('close', function() use ($promise) {
-                $promise->cancel();
-            });
-        }
-
         $this->promise = $promise->then(
             function ($stream) {
                 if (!($stream instanceof ReadableStreamInterface)) {
@@ -106,6 +99,11 @@ public function close()
 
         $this->closed = true;
 
+        // try to cancel promise once the stream closes
+        if ($this->promise instanceof CancellablePromiseInterface) {
+            $this->promise->cancel();
+        }
+
         $this->emit('end', array($this));
         $this->emit('close', array($this));
     }

tests/UnwrapReadableTest.php

@@ -153,4 +153,15 @@ public function testEmitsEndAndClosesWhenInputEmitsEnd()
 
         $this->assertFalse($stream->isReadable());
     }
+
+    public function testEmitsCloseOnlyOnceWhenClosingStreamMultipleTimes()
+    {
+        $promise = new Promise\Promise(function () { });
+        $stream = Stream\unwrapReadable($promise);
+
+        $stream->on('close', $this->expectCallableOnce());
+
+        $stream->close();
+        $stream->close();
+    }
 }