From 6c6c7b9e1fd93007701976c35c47ec444ea612bc Mon Sep 17 00:00:00 2001
From: Samuel Georges <sam@daftspunk.com>
Date: Sat, 27 Jun 2015 13:37:34 +1000
Subject: [PATCH] Implement ComposerManager::autoload for plugins that use
 composer. All packages are now added to a global pool to prevent double
 loading and the load order is respected. Refs #1227

---
 CHANGELOG.md                               |   3 +-
 modules/system/classes/ComposerManager.php | 126 +++++++++++++++++++++
 modules/system/classes/PluginManager.php   |   2 +-
 3 files changed, 129 insertions(+), 2 deletions(-)
 create mode 100644 modules/system/classes/ComposerManager.php

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 9791cf245..4f2e15ca2 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,6 @@
 * **Build 27x** (2015-06-xx)
- - List columns now support specifying a `default` option used when the value would otherwise be null.
+  - List columns now support specifying a `default` option used when the value would otherwise be null.
+  - Implement a custom autoloader for plugins that use composer. Now only one instance of composer is used, all packages are now added to a global pool to prevent double loading and the load order is respected.
 
 * **Build 272** (2015-06-27)
   - Protected images and their thumbnails are now supported in the back-end.
diff --git a/modules/system/classes/ComposerManager.php b/modules/system/classes/ComposerManager.php
new file mode 100644
index 000000000..741eba2ea
--- /dev/null
+++ b/modules/system/classes/ComposerManager.php
@@ -0,0 +1,126 @@
+<?php namespace System\Classes;
+
+use Composer\Autoload\ClassLoader as ComposerLoader;
+
+/**
+ * Composer manager
+ *
+ * This class manages composer packages introduced by plugins. Each loaded
+ * package is added to a global pool to ensure a package is not loaded
+ * twice by the composer instance introduced by a plugin. This class
+ * is used as a substitute for the vendor/autoload.php file.
+ *
+ * @package october\system
+ * @author Alexey Bobkov, Samuel Georges
+ */
+class ComposerManager
+{
+    use \October\Rain\Support\Traits\Singleton;
+
+    protected $namespacePool = [];
+
+    protected $psr4Pool = [];
+
+    protected $classMapPool = [];
+
+    protected $includeFilesPool = [];
+
+    /**
+     * @var Composer\Autoload\ClassLoader The primary composer instance.
+     */
+    protected $loader;
+
+    public function init()
+    {
+        $this->loader = include base_path() .'/vendor/autoload.php';
+        $this->preloadPools();
+    }
+
+    protected function preloadPools()
+    {
+        $this->classMapPool = array_fill_keys(array_keys($this->loader->getClassMap()), true);
+        $this->namespacePool = array_fill_keys(array_keys($this->loader->getPrefixes()), true);
+        $this->psr4Pool = array_fill_keys(array_keys($this->loader->getPrefixesPsr4()), true);
+        $this->includeFilesPool = $this->preloadIncludeFilesPool();
+    }
+
+    protected function preloadIncludeFilesPool()
+    {
+        $result = [];
+        $vendorPath = base_path() .'/vendor';
+
+        if (file_exists($file = $vendorPath . '/composer/autoload_files.php')) {
+            $includeFiles = require $file;
+            foreach ($includeFiles as $includeFile) {
+                $relativeFile = $this->stripVendorDir($includeFile, $vendorPath);
+                $result[$relativeFile] = true;
+            }
+        }
+
+        return $result;
+    }
+
+    /**
+     * Similar function to including vendor/autoload.php.
+     * @param string $vendorPath Absoulte path to the vendor directory.
+     * @return void
+     */
+    public function autoload($vendorPath)
+    {
+        $dir = $vendorPath . '/composer';
+
+        if (file_exists($file = $dir . '/autoload_namespaces.php')) {
+            $map = require $file;
+            foreach ($map as $namespace => $path) {
+                if (isset($this->namespacePool[$namespace])) continue;
+                $this->loader->set($namespace, $path);
+                $this->namespacePool[$namespace] = true;
+            }
+        }
+
+        if (file_exists($file = $dir . '/autoload_psr4.php')) {
+            $map = require $file;
+            foreach ($map as $namespace => $path) {
+                if (isset($this->psr4Pool[$namespace])) continue;
+                $this->loader->setPsr4($namespace, $path);
+                $this->psr4Pool[$namespace] = true;
+            }
+        }
+
+        if (file_exists($file = $dir . '/autoload_classmap.php')) {
+            $classMap = require $file;
+            if ($classMap) {
+                $classMapDiff = array_diff_key($classMap, $this->classMapPool);
+                $this->loader->addClassMap($classMapDiff);
+                $this->classMapPool += array_fill_keys(array_keys($classMapDiff), true);
+            }
+        }
+
+        if (file_exists($file = $dir . '/autoload_files.php')) {
+            $includeFiles = require $file;
+            foreach ($includeFiles as $includeFile) {
+                $relativeFile = $this->stripVendorDir($includeFile, $vendorPath);
+                if (isset($this->includeFilesPool[$relativeFile])) continue;
+                require $includeFile;
+                $this->includeFilesPool[$relativeFile] = true;
+            }
+        }
+    }
+
+    /**
+     * Removes the vendor directory from a path.
+     * @param string $path
+     * @return string
+     */
+    protected function stripVendorDir($path, $vendorDir)
+    {
+        $path = realpath($path);
+        $vendorDir = realpath($vendorDir);
+
+        if (strpos($path, $vendorDir) === 0) {
+            $path = substr($path, strlen($vendorDir));
+        }
+
+        return $path;
+    }
+}
\ No newline at end of file
diff --git a/modules/system/classes/PluginManager.php b/modules/system/classes/PluginManager.php
index d0cda58c4..fe53d7eda 100644
--- a/modules/system/classes/PluginManager.php
+++ b/modules/system/classes/PluginManager.php
@@ -178,7 +178,7 @@ class PluginManager
          */
         $autoloadPath = $pluginPath . '/vendor/autoload.php';
         if (File::isFile($autoloadPath)) {
-            require_once $autoloadPath;
+            ComposerManager::instance()->autoload($pluginPath . '/vendor');
         }
 
         if (!self::$noInit || $plugin->elevated) {