add Nailgun based ClosureCompiler

lib/Minify/NailgunClosureCompiler.php

@@ -0,0 +1,104 @@
+<?php
+
+/**
+ * Class Minify_ClosureCompiler
+ * @package Minify
+ */
+
+/**
+ * Run Closure Compiler via NailGun
+ *
+ * @package Minify
+ * @author Elan Ruusamäe <glen@delfi.ee>
+ * @link https://github.com/martylamb/nailgun
+ */
+class Minify_NailgunClosureCompiler extends Minify_ClosureCompiler
+{
+    const NG_SERVER = 'com.martiansoftware.nailgun.NGServer';
+    const CC_MAIN = 'com.google.javascript.jscomp.CommandLineRunner';
+
+    // exit code that ng gives
+    // FIXME: figure out the meaning of the value
+    const NG_EXIT_CODE = 227;
+
+    /**
+     * Filepath of "ng" executable (from Nailgun package)
+     *
+     * @var string
+     */
+    public static $ngExecutable = 'ng';
+
+    /**
+     * Filepath of the Nailgun jar file.
+     *
+     * @var string
+     */
+    public static $ngJarFile;
+
+    /**
+     * Get command to launch NailGun server.
+     *
+     * @return array
+     */
+    protected function getServerCommandLine()
+    {
+        $this->checkJar(self::$ngJarFile);
+        $this->checkJar(self::$jarFile);
+
+        $classPath = array(
+            self::$ngJarFile,
+            self::$jarFile,
+        );
+
+        // The command for the server that should show up in the process list
+        $server = array(
+            self::$javaExecutable,
+            '-server',
+            '-cp', join(':', $classPath),
+            self::NG_SERVER,
+        );
+
+        return $server;
+    }
+
+    /**
+     * @return array
+     * @throws Minify_ClosureCompiler_Exception
+     */
+    protected function getCompilerCommandLine()
+    {
+        $server = array(
+            self::$ngExecutable,
+            escapeshellarg(self::CC_MAIN)
+        );
+
+        return $server;
+    }
+
+    /**
+     * @param string $tmpFile
+     * @param array $options
+     * @return string
+     * @throws Minify_ClosureCompiler_Exception
+     */
+    protected function compile($tmpFile, $options)
+    {
+        $this->startServer();
+
+        $command = $this->getCommand($options, $tmpFile);
+
+        return implode("\n", $this->shell($command, array(self::NG_EXIT_CODE)));
+    }
+
+    private function startServer()
+    {
+        $serverCommand = join(' ', $this->getServerCommandLine());
+        $psCommand = $this->shell("ps -o cmd= -C " . self::$javaExecutable);
+        if (array_search($serverCommand, $psCommand) !== false) {
+            // already started!
+            return;
+        }
+
+        $this->shell("$serverCommand </dev/null >/dev/null 2>/dev/null & sleep 10");
+    }
+}