Allow modules to live outside of app/code directory

Author: joshdifabio

app/etc/di.xml

@@ -44,6 +44,7 @@
     <preference for="Magento\Framework\Config\CacheInterface" type="Magento\Framework\App\Cache\Type\Config" />
     <preference for="Magento\Framework\Config\ValidationStateInterface" type="Magento\Framework\App\Arguments\ValidationState" />
     <preference for="Magento\Framework\Module\ModuleListInterface" type="Magento\Framework\Module\ModuleList" />
+    <preference for="Magento\Framework\Module\Dir\ResolverInterface" type="Magento\Framework\Module\Dir\Resolver" />
     <preference for="Magento\Framework\Event\ConfigInterface" type="Magento\Framework\Event\Config" />
     <preference for="Magento\Framework\Event\InvokerInterface" type="Magento\Framework\Event\Invoker\InvokerDefault" />
     <preference for="Magento\Framework\Interception\PluginListInterface" type="Magento\Framework\Interception\PluginList\PluginList" />

lib/internal/Magento/Framework/Module/Dir.php

@@ -10,6 +10,8 @@
 use Magento\Framework\App\Filesystem\DirectoryList;
 use Magento\Framework\Filesystem;
 use Magento\Framework\Filesystem\Directory\ReadInterface;
+use Magento\Framework\Stdlib\String as StringHelper;
+use Magento\Framework\Module\Dir\ResolverInterface;
 
 class Dir
 {
@@ -25,14 +27,23 @@ class Dir
      */
     protected $_string;
 
+    /**
+     * Module directory resolver
+     *
+     * @var ResolverInterface
+     */
+    private $dirResolver;
+
     /**
      * @param Filesystem $filesystem
-     * @param \Magento\Framework\Stdlib\String $string
+     * @param StringHelper $string
+     * @param ResolverInterface $resolver
      */
-    public function __construct(Filesystem $filesystem, \Magento\Framework\Stdlib\String $string)
+    public function __construct(Filesystem $filesystem, StringHelper $string, ResolverInterface $resolver)
     {
         $this->_modulesDirectory = $filesystem->getDirectoryRead(DirectoryList::MODULES);
         $this->_string = $string;
+        $this->dirResolver = $resolver;
     }
 
     /**
@@ -45,7 +56,10 @@ public function __construct(Filesystem $filesystem, \Magento\Framework\Stdlib\St
      */
     public function getDir($moduleName, $type = '')
     {
-        $path = $this->_string->upperCaseWords($moduleName, '_', '/');
+        if (null === $path = $this->dirResolver->getModulePath($moduleName)) {
+            $path = $this->_string->upperCaseWords($moduleName, '_', '/');
+        }
+        
         if ($type) {
             if (!in_array($type, ['etc', 'i18n', 'view', 'Controller'])) {
                 throw new \InvalidArgumentException("Directory type '{$type}' is not recognized.");

lib/internal/Magento/Framework/Module/Dir/Resolver.php

@@ -0,0 +1,49 @@
+<?php
+/**
+ * Copyright © 2015 Magento. All rights reserved.
+ * See COPYING.txt for license details.
+ */
+
+namespace Magento\Framework\Module\Dir;
+
+/**
+ * Provides ability to statically register modules which do not reside in the modules directory
+ *
+ * @author Josh Di Fabio <joshdifabio@gmail.com>
+ */
+final class Resolver implements ResolverInterface
+{
+    /**
+     * Paths to modules
+     *
+     * @var string[]
+     */
+    private static $modulePaths = [];
+
+    /**
+     * Sets the location of a module. Necessary for modules which do not reside in modules directory
+     *
+     * @param string $moduleName Fully-qualified module name
+     * @param string $path Absolute file path to the module
+     */
+    public static function setModulePath($moduleName, $path)
+    {
+        self::$modulePaths[$moduleName] = $path;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function getModulePaths()
+    {
+        return self::$modulePaths;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function getModulePath($moduleName)
+    {
+        return isset(self::$modulePaths[$moduleName]) ? self::$modulePaths[$moduleName] : null;
+    }
+}

lib/internal/Magento/Framework/Module/Dir/ResolverInterface.php

@@ -0,0 +1,29 @@
+<?php
+/**
+ * List of active application modules.
+ *
+ * Copyright © 2015 Magento. All rights reserved.
+ * See COPYING.txt for license details.
+ */
+namespace Magento\Framework\Module\Dir;
+
+/**
+ * @author Josh Di Fabio <joshdifabio@gmail.com>
+ */
+interface ResolverInterface
+{
+    /**
+     * Get list of Magento module paths
+     *
+     * Returns an array where key is fully-qualified module name and value is absolute path to module
+     *
+     * @return array
+     */
+    public function getModulePaths();
+
+    /**
+     *
+     * @param string $moduleName
+     */
+    public function getModulePath($moduleName);
+}

lib/internal/Magento/Framework/Module/ModuleList/Loader.php

@@ -10,6 +10,8 @@
 use Magento\Framework\Filesystem;
 use Magento\Framework\Module\Declaration\Converter\Dom;
 use Magento\Framework\Xml\Parser;
+use Magento\Framework\Module\Dir\ResolverInterface;
+use Magento\Framework\Filesystem\Directory\ReadInterface;
 
 /**
  * Loader of module list information from the filesystem
@@ -37,19 +39,28 @@ class Loader
      */
     private $parser;
 
+    /**
+     * Module directory resolver
+     *
+     * @var ResolverInterface
+     */
+    private $dirResolver;
+
     /**
      * Constructor
      *
      * @param Filesystem $filesystem
      * @param Dom $converter
      * @param Parser $parser
+     * @param ResolverInterface $resolver
      */
-    public function __construct(Filesystem $filesystem, Dom $converter, Parser $parser)
+    public function __construct(Filesystem $filesystem, Dom $converter, Parser $parser, ResolverInterface $resolver)
     {
         $this->filesystem = $filesystem;
         $this->converter = $converter;
         $this->parser = $parser;
         $this->parser->initErrorHandler();
+        $this->dirResolver = $resolver;
     }
 
     /**
@@ -62,7 +73,7 @@ public function load()
     {
         $result = [];
         $dir = $this->filesystem->getDirectoryRead(DirectoryList::MODULES);
-        foreach ($dir->search('*/*/etc/module.xml') as $file) {
+        foreach ($this->getModuleConfigPaths($dir) as $file) {
             $contents = $dir->readFile($file);
 
             try {
@@ -84,6 +95,23 @@ public function load()
         return $this->sortBySequence($result);
     }
 
+    /**
+     * Get an array containing the absolute file paths to all known module.xml files
+     *
+     * @param ReadInterface $modulesDir
+     * @return array
+     */
+    private function getModuleConfigPaths(ReadInterface $modulesDir)
+    {
+        $moduleConfigPaths = $modulesDir->search('*/*/etc/module.xml');
+
+        foreach ($this->dirResolver->getModulePaths() as $modulePath) {
+            $moduleConfigPaths[] = $modulesDir->getAbsolutePath("$modulePath/etc/modules.xml");
+        }
+
+        return array_unique($moduleConfigPaths);
+    }
+
     /**
      * Sort the list of modules using "sequence" key in meta-information
      *