WIP: Try to parallelize linting with amphp

composer.json

@@ -14,9 +14,10 @@
         }
     ],
     "require": {
-        "php": "^5.6 || ^7.0",
+        "php": "^7.0",
         "ext-json": "*",
         "ext-tokenizer": "*",
+        "amphp/parallel": "^1.2",
         "composer/semver": "^1.4",
         "composer/xdebug-handler": "^1.2",
         "doctrine/annotations": "^1.2",

src/Linter/Linter.php

@@ -32,10 +32,13 @@ final class Linter implements LinterInterface
     public function __construct($executable = null)
     {
         try {
-            $this->sublinter = new TokenizerLinter();
+            // XXX feature detect the pooled linter
+            $this->sublinter = new PooledLinter();
+            // $this->sublinter = new TokenizerLinter();
         } catch (UnavailableLinterException $e) {
             $this->sublinter = new ProcessLinter($executable);
         }
+        var_dump(get_class($this->sublinter));
     }
 
     /**

src/Linter/PooledLinter.php

@@ -0,0 +1,94 @@
+<?php
+
+/*
+ * This file is part of PHP CS Fixer.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *     Dariusz Rumiński <dariusz.ruminski@gmail.com>
+ *
+ * This source file is subject to the MIT license that is bundled
+ * with this source code in the file LICENSE.
+ */
+
+namespace PhpCsFixer\Linter;
+
+use Amp\Parallel\Worker\DefaultPool;
+use Amp\Parallel\Worker\Environment;
+use Amp\Parallel\Worker\Task;
+
+class PooledLinter implements  LinterInterface
+{
+    private $processPool;
+
+    public function __construct()
+    {
+        $this->processPool = new DefaultPool();
+    }
+
+    public function __destruct()
+    {
+        yield $this->processPool->shutdown();
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function isAsync()
+    {
+        return true;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function lintFile($path)
+    {
+        return new PooledLintingResult($this->processPool->enqueue($this->createTaskForFile($path)));
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function lintSource($source)
+    {
+        return new PooledLintingResult($this->processPool->enqueue($this->createTaskForSource($source)));
+    }
+
+    private function createTaskForFile($path) {
+        return new class($path) implements Task {
+            private $path;
+
+            public function __construct($path)
+            {
+                $this->path = $path;
+            }
+
+            /**
+             * @inheritDoc
+             */
+            public function run(Environment $environment) {
+                $linter = new TokenizerLinter();
+                return $linter->lintFile($this->path);
+            }
+        };
+    }
+
+    private function createTaskForSource($source) {
+        return new class($source) implements Task {
+            private $source;
+
+            public function __construct($source)
+            {
+                $this->source = $source;
+            }
+
+            /**
+             * @inheritDoc
+             */
+            public function run(Environment $environment) {
+                $linter = new TokenizerLinter();
+                return $linter->lintSource($this->source);
+            }
+        };
+    }
+}

src/Linter/PooledLintingResult.php

@@ -0,0 +1,60 @@
+<?php
+
+/*
+ * This file is part of PHP CS Fixer.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *     Dariusz Rumiński <dariusz.ruminski@gmail.com>
+ *
+ * This source file is subject to the MIT license that is bundled
+ * with this source code in the file LICENSE.
+ */
+
+namespace PhpCsFixer\Linter;
+
+use Amp\Parallel\Worker\Task;
+use Amp\Promise;
+use Symfony\Component\Process\Process;
+
+/**
+ * @internal
+ */
+final class PooledLintingResult implements LintingResultInterface
+{
+    /**
+     * @var bool
+     */
+    private $isSuccessful;
+
+    /**
+     * @var Promise
+     */
+    private $promise;
+
+    public function __construct(Promise $promise)
+    {
+        $this->promise = $promise;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function check()
+    {
+        if (!$this->isSuccessful()) {
+            // on some systems stderr is used, but on others, it's not
+            throw new LintingException('error 213', 890);
+            //throw new LintingException($this->process->getErrorOutput() ?: $this->process->getOutput(), $this->process->getExitCode());
+        }
+    }
+
+
+    private function isSuccessful()
+    {
+        if (null === $this->isSuccessful) {
+            $this->isSuccessful = yield $this->promise;
+        }
+
+        return $this->isSuccessful;
+    }
+}