ClassLoader: completely refactored

library/Icinga/Application/ClassLoader.php

@@ -3,6 +3,8 @@
 
 namespace Icinga\Application;
 
+use Zend_Loader_Autoloader;
+
 /**
  * PSR-4 class loader
  */
@@ -13,6 +15,40 @@ class ClassLoader
      */
     const NAMESPACE_SEPARATOR = '\\';
 
+    /**
+     * Icinga Web 2 module namespace prefix
+     */
+    const MODULE_PREFIX = 'Icinga\\Module\\';
+
+    /**
+     * Icinga Web 2 module namespace prefix length
+     *
+     * Helps to make substr/strpos operations even faster
+     */
+    const MODULE_PREFIX_LENGTH = 14;
+
+    /**
+     * A hardcoded class/subdir map for application ns prefixes
+     *
+     * When a module registers with an application directory, those
+     * namespace prefixes (after the module prefix) will be looked up
+     * in the corresponding application subdirectories
+     *
+     * @var array
+     */
+    protected $applicationPrefixes = array(
+        'Clicommands' => 'clicommands',
+        'Controllers' => 'controllers',
+        'Forms'       => 'forms'
+    );
+
+    /**
+     * Whether we already instantiated the ZF autoloader
+     *
+     * @var boolean
+     */
+    protected $gotZend = false;
+
     /**
      * Namespaces
      *
@@ -20,18 +56,33 @@ class ClassLoader
      */
     private $namespaces = array();
 
+    /**
+     * Application directories
+     *
+     * @var array
+     */
+    private $applicationDirectories = array();
+
     /**
      * Register a base directory for a namespace prefix
      *
+     * Application directory is optional and provides additional lookup
+     * logic for hardcoded namespaces like "Forms"
+     *
      * @param   string  $namespace
      * @param   string  $directory
+     * @param   string  $appDirectory
      *
      * @return  $this
      */
-    public function registerNamespace($namespace, $directory)
+    public function registerNamespace($namespace, $directory, $appDirectory = null)
     {
         $this->namespaces[$namespace] = $directory;
 
+        if ($appDirectory !== null) {
+            $this->applicationDirectories[$namespace] = $appDirectory;
+        }
+
         return $this;
     }
 
@@ -56,21 +107,177 @@ class ClassLoader
      */
     public function getSourceFile($class)
     {
+        if ($file = $this->getModuleSourceFile($class)) {
+            return $file;
+        }
+
         foreach ($this->namespaces as $namespace => $dir) {
             if ($class === strstr($class, $namespace)) {
-                $classPath = str_replace(
-                    self::NAMESPACE_SEPARATOR,
-                    DIRECTORY_SEPARATOR,
-                    substr($class, strlen($namespace))
-                ) . '.php';
-                if (file_exists($file = $dir . $classPath)) {
-                    return $file;
-                }
+                return $this->buildClassFilename($class, $namespace);
             }
         }
+
         return null;
     }
 
+    /**
+     * Get the source file of the given module class or interface
+     *
+     * @param   string      $class Module class or interface name
+     *
+     * @return  string|null
+     */
+    protected function getModuleSourceFile($class)
+    {
+        if (! $this->classBelongsToModule($class)) {
+            return null;
+        }
+
+        $modules = Icinga::app()->getModuleManager();
+        $namespace = $this->extractModuleNamespace($class);
+
+        if ($this->hasNamespace($namespace)) {
+
+            return $this->buildClassFilename($class, $namespace);
+
+        } elseif (! $modules->loadedAllEnabledModules()) {
+
+            $moduleName = $this->extractModuleName($class);
+
+            if ($modules->hasEnabled($moduleName)) {
+                $modules->loadModule($moduleName);
+
+                return $this->buildClassFilename($class, $namespace);
+            }
+        }
+
+        return null;
+    }
+
+    /**
+     * Extract the Icinga module namespace from a given namespaced class name
+     *
+     * Does no validation, prefix must have been checked before
+     *
+     * @return string
+     */
+    protected function extractModuleNamespace($class)
+    {
+        return substr(
+            $class,
+            0,
+            strpos($class, self::NAMESPACE_SEPARATOR, self::MODULE_PREFIX_LENGTH + 1)
+        );
+    }
+
+    /**
+     * Extract the Icinga module name from a given namespaced class name
+     *
+     * Does no validation, prefix must have been checked before
+     *
+     * @return string
+     */
+    protected function extractModuleName($class)
+    {
+        return lcfirst(
+            substr(
+                $class,
+                self::MODULE_PREFIX_LENGTH,
+                strpos(
+                    $class,
+                    self::NAMESPACE_SEPARATOR,
+                    self::MODULE_PREFIX_LENGTH + 1
+                ) - self::MODULE_PREFIX_LENGTH
+            )
+        );
+    }
+
+    /**
+     * Whether the given class name belongs to a module namespace
+     *
+     * @return boolean
+     */
+    protected function classBelongsToModule($class)
+    {
+        return substr($class, 0, self::MODULE_PREFIX_LENGTH) === self::MODULE_PREFIX;
+    }
+
+    /**
+     * Prepare a filename string for the given class
+     *
+     * Expects the given namespace to be registered with a path name
+     *
+     * @return string
+     */
+    protected function buildClassFilename($class, $namespace)
+    {
+        $relNs = substr($class, strlen($namespace) + 1);
+
+        if ($this->namespaceHasApplictionDirectory($namespace)) {
+            $prefixSeparator = strpos($relNs, self::NAMESPACE_SEPARATOR);
+            $prefix = substr($relNs, 0, $prefixSeparator);
+
+            if ($this->isApplicationPrefix($prefix)) {
+                return $this->applicationDirectories[$namespace]
+                    . DIRECTORY_SEPARATOR
+                    . $this->applicationPrefixes[$prefix]
+                    . $this->classToRelativePhpFilename(substr($relNs, $prefixSeparator));
+            }
+        }
+
+        return $this->namespaces[$namespace] . DIRECTORY_SEPARATOR . $this->classToRelativePhpFilename($relNs);
+    }
+
+    /**
+     * Return the relative file name for the given (namespaces) class
+     *
+     * @param  string $class
+     *
+     * @return string
+     */
+    protected function classToRelativePhpFilename($class)
+    {
+        return str_replace(
+            self::NAMESPACE_SEPARATOR,
+            DIRECTORY_SEPARATOR,
+            $class
+        ) . '.php';
+    }
+
+    /**
+     * Whether given prefix (Forms, Controllers...) makes part of "application"
+     *
+     * @param  string $prefix 
+     *
+     * @return boolean
+     */
+    protected function isApplicationPrefix($prefix)
+    {
+        return array_key_exists($prefix, $this->applicationPrefixes);
+    }
+
+    /**
+     * Whether the given namespace registered an application directory
+     *
+     * @return boolean
+     */
+    protected function namespaceHasApplictionDirectory($namespace)
+    {
+        return array_key_exists($namespace, $this->applicationDirectories);
+    }
+
+    /**
+     * Require ZF autoloader
+     *
+     * @return Zend_Loader_Autoloader
+     */
+    protected function requireZendAutoloader()
+    {
+        require_once 'Zend/Loader/Autoloader.php';
+        $this->gotZend = true;
+        return Zend_Loader_Autoloader::getInstance();
+    }
+
     /**
      * Load the given class or interface
      *
@@ -80,10 +287,22 @@ class ClassLoader
      */
     public function loadClass($class)
     {
-        if ($file = $this->getSourceFile($class)) {
-            require $file;
-            return true;
+        // We are aware of the Zend_ prefix and lazyload it's autoloader.
+        // Return as fast as possible if we already did so.
+        if (substr($class, 0, 5) === 'Zend_') {
+            if (! $this->gotZend) {
+                $this->requireZendAutoloader();
+            }
+            return false;
         }
+
+        if ($file = $this->getSourceFile($class)) {
+            if (file_exists($file)) {
+                require $file;
+                return true;
+            }
+        }
+
         return false;
     }