Refactor process to unreference exit code stream

src/Process/Process.php

@@ -4,7 +4,8 @@ namespace Icicle\Concurrent\Process;
 use Exception;
 use Icicle\Concurrent\Exception\ProcessException;
 use Icicle\Concurrent\Exception\StatusError;
-use Icicle\Coroutine\Coroutine;
+use Icicle\Loop;
+use Icicle\Promise\Promise;
 use Icicle\Socket\Stream\ReadableStream;
 use Icicle\Socket\Stream\WritableStream;
 
@@ -56,10 +57,15 @@ class Process
     private $pid = 0;
 
     /**
-     * @var \Icicle\Promise\PromiseInterface
+     * @var \Icicle\Promise\PromiseInterface|null
      */
     private $promise;
 
+    /**
+     * @var \Icicle\Loop\Events\SocketEventInterface|null
+     */
+    private $poll;
+
     /**
      * @param   string $command Command to run.
      * @param   string|null $cwd Working directory or use an empty string to use the working directory of the current
@@ -91,6 +97,7 @@ class Process
     {
         $this->process = null;
         $this->promise = null;
+        $this->poll = null;
         $this->pid = 0;
         $this->stdin = null;
         $this->stdout = null;
@@ -135,12 +142,22 @@ class Process
         $this->stdout = new ReadableStream($pipes[1]);
         $this->stderr = new ReadableStream($pipes[2]);
 
-        $stream = new ReadableStream($pipes[3]);
+        $stream = $pipes[3];
+        stream_set_blocking($stream, 0);
 
-        $this->promise = (new Coroutine($stream->read()))
+        $this->promise = new Promise(function (callable $resolve) use ($stream) {
+            $this->poll = Loop\poll($stream, function ($resource) use ($resolve) {
+                $resolve((string) fread($resource, 1));
+            });
+
+            $this->poll->unreference();
+            $this->poll->listen();
+        });
+
+        $this->promise = $this->promise
             ->then(function ($code) {
                 if ('' === $code) {
-                    throw new Exception('Process ended unexpectedly.');
+                    throw new Exception('Process ended unexpectedly without providing a status code.');
                 }
                 return (int) $code;
             })
@@ -150,7 +167,7 @@ class Process
                     $this->process = null;
                 }
                 $this->stdin->close();
-                $stream->close();
+                $this->poll->free();
             });
     }
 
@@ -167,6 +184,8 @@ class Process
             throw new StatusError('The process has not been started.');
         }
 
+        $this->poll->reference();
+
         try {
             yield $this->promise;
         } finally {