From 592adae6c1b742b380a8b1a3f61035f9fc2f4bac Mon Sep 17 00:00:00 2001
From: Stephen Nielson <snielson@discoverandchange.com>
Date: Thu, 11 Aug 2022 15:32:52 -0400
Subject: [PATCH] Fixes #5643 ModulesClassLoader autoload module code without
 composer install (#5644)

* Fixes #5643 ModulesClassLoader

Implemented a modules class loader that allow module writers to register
a namespace if its not already been registered.  This makes it so the
ModuleWriter doesn't have to use requires everywhere and a module can be
just dropped into the filesystem and execute once its been registered
and installed from the Manage Modules interface.

* Style fixes
---
 src/Core/ModulesApplication.php | 10 +++--
 src/Core/ModulesClassLoader.php | 81 +++++++++++++++++++++++++++++++++++++++++
 2 files changed, 87 insertions(+), 4 deletions(-)
 create mode 100644 src/Core/ModulesClassLoader.php

diff --git a/src/Core/ModulesApplication.php b/src/Core/ModulesApplication.php
index 262e8b830..b0207c24e 100644
--- a/src/Core/ModulesApplication.php
+++ b/src/Core/ModulesApplication.php
@@ -67,10 +67,12 @@ class ModulesApplication
             $db_modules[] = $row["mod_name"];
         }
 
-        $this->bootstrapCustomModules($kernel->getEventDispatcher(), $customModulePath);
+        // let's get our autoloader that people can tie into if they need it
+        $autoloader = new ModulesClassLoader($webRootPath);
+        $this->bootstrapCustomModules($autoloader, $kernel->getEventDispatcher(), $customModulePath);
     }
 
-    private function bootstrapCustomModules($eventDispatcher, $customModulePath)
+    private function bootstrapCustomModules(ModulesClassLoader $classLoader, $eventDispatcher, $customModulePath)
     {
         // we skip the audit log as it has no bearing on user activity and is core system related...
         $resultSet = sqlStatementNoLog($statement = "SELECT mod_name, mod_directory FROM modules WHERE mod_active = 1 AND type != 1 ORDER BY `mod_ui_order`, `date`");
@@ -93,13 +95,13 @@ class ModulesApplication
             }
         }
         foreach ($db_modules as $module) {
-            $this->loadCustomModule($module, $eventDispatcher);
+            $this->loadCustomModule($classLoader, $module, $eventDispatcher);
         }
         // TODO: stephen we should fire an event saying we've now loaded all the modules here.
         // Unsure who'd be listening or care.
     }
 
-    private function loadCustomModule($module, $eventDispatcher)
+    private function loadCustomModule(ModulesClassLoader $classLoader, $module, $eventDispatcher)
     {
         try {
             // the only thing in scope here is $module and $eventDispatcher which is ok for our bootstrap piece.
diff --git a/src/Core/ModulesClassLoader.php b/src/Core/ModulesClassLoader.php
new file mode 100644
index 000000000..12c216e98
--- /dev/null
+++ b/src/Core/ModulesClassLoader.php
@@ -0,0 +1,81 @@
+<?php
+
+/**
+ * ModulesClassLoader is made available in every custom_module's openemr.bootstrap.php file as the variable $classLoader.
+ * Modules can use the ModulesClassLoader to register their namespace in order to auto load their classes.  This facilitates
+ * modules being dropped into the filesystem without having to go through a composer install / dumping of the autoloader.
+ *
+ * The class loader will check to make sure a namespace has not already been registered in case the module is installed
+ * via composer and is already in the namespace heirarchy.  Note this means each module needs to have its own DISTINCT
+ * namespace and should not share a namespace as the very first module that registers with the namespace is the one
+ * made available to OpenEMR.
+ *
+ * For performance reasons, if a module writer wishes to avoid hitting the filesystem for class discovery, they can use
+ * the registerClassmap function to optimize their runtime performance.
+ *
+ * An example use in an openemr.bootstrap.php file is as follows:
+ * <example>
+ * // openemr.bootstrap.php
+ * namespace Acme\OpenEMR\Modules\MyUniqueModule;
+ * use OpenEMR\Core\ModulesClassLoader;
+ * // @global ModulesClassLoader $classLoader
+ * $classLoader->registerNamespaceIfNotExists('Acme\\OpenEMR\\Modules\\MyUniqueModule\\', __DIR__ . DIRECTORY_SEPARATOR . 'src');
+ * // run any other custom module code needed here.
+ * </example>
+ *
+ * @package   OpenEMR
+ * @link      http://www.open-emr.org
+ *
+ * @author    Stephen Nielson <stephen@nielson.org>
+ * @copyright Copyright (c) 2019 Stephen Nielson <stephen@nielson.org>
+ * @license   https://github.com/openemr/openemr/blob/master/LICENSE GNU General Public License 3
+ */
+
+namespace OpenEMR\Core;
+
+use Composer\Autoload\ClassLoader;
+
+class ModulesClassLoader
+{
+    /**
+     * @var ClassLoader
+     */
+    private $classLoader;
+
+    public function __construct($webRootPath)
+    {
+        $this->classLoader = require $webRootPath . DIRECTORY_SEPARATOR . 'vendor' . DIRECTORY_SEPARATOR . 'autoload.php';
+    }
+
+    /**
+     * Registers a set of PSR-4 directories for a given namespace.  If the namespace already exists it skips registering
+     * the namespace (such as if the module has been installed via the main composer.json file)
+     *
+     * @param string          $prefix  The prefix/namespace, with trailing '\\'
+     * @param string[]|string $paths   The PSR-4 base directories to
+     *
+     * @throws \InvalidArgumentException
+     *
+     * @return void
+     */
+    public function registerNamespaceIfNotExists($namespace, $paths)
+    {
+        $prefixes = $this->classLoader->getPrefixesPsr4();
+        if (empty($prefixes[$namespace])) {
+            $this->classLoader->addPsr4($namespace, $paths);
+            return true;
+        }
+        return false;
+    }
+
+    /**
+     * @param string[] $classMap Class to filename map
+     * @psalm-param array<string, string> $classMap
+     *
+     * @return void
+     */
+    public function registerClassmap($classMap)
+    {
+        $this->classLoader->addClassMap($classMap);
+    }
+}
-- 
2.11.4.GIT