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libphutil/src/__phutil_library_init__.php
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__phutil_library_init__.php
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<?php
/*
* Copyright 2012 Facebook, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
define('__LIBPHUTIL__', true);
/**
* @group library
*/
function phutil_require_module($library, $module) {
PhutilBootloader::getInstance()->loadModule($library, $module);
}
/**
* @group library
*/
function phutil_require_source($source) {
PhutilBootloader::getInstance()->loadSource($source);
}
/**
* @group library
*/
function phutil_register_library($library, $path) {
PhutilBootloader::getInstance()->registerLibrary($library, $path);
}
/**
* @group library
*/
function phutil_register_library_map(array $map) {
PhutilBootloader::getInstance()->registerLibraryMap($map);
}
/**
* @group library
*/
function phutil_load_library($path) {
PhutilBootloader::getInstance()->loadLibrary($path);
}
/**
* @group library
*/
final class PhutilBootloader {
private static $instance;
private $registeredLibraries = array();
private $libraryMaps = array();
private $moduleStack = array();
private $currentLibrary = null;
public static function getInstance() {
if (!self::$instance) {
self::$instance = new PhutilBootloader();
}
return self::$instance;
}
private function __construct() {
// This method intentionally left blank.
}
public function registerLibrary($name, $path) {
if (basename($path) != '__phutil_library_init__.php') {
throw new PhutilBootloaderException(
'Only directories with a __phutil_library_init__.php file may be '.
'registered as libphutil libraries.');
}
$path = dirname($path);
// Detect attempts to load the same library multiple times from different
// locations. This might mean you're doing something silly like trying to
// include two different versions of something, or it might mean you're
// doing something subtle like running a different version of 'arc' on a
// working copy of Arcanist.
if (isset($this->registeredLibraries[$name])) {
$old_path = $this->registeredLibraries[$name];
if ($old_path != $path) {
throw new PhutilLibraryConflictException($name, $old_path, $path);
}
}
$this->registeredLibraries[$name] = $path;
return $this;
}
public function registerLibraryMap(array $map) {
$this->libraryMaps[$this->currentLibrary] = $map;
return $this;
}
public function getLibraryMap($name) {
if (empty($this->libraryMaps[$name])) {
$root = $this->getLibraryRoot($name);
$this->currentLibrary = $name;
$okay = include $root.'/__phutil_library_map__.php';
if (!$okay) {
throw new PhutilBootloaderException(
"Include of '{$root}/__phutil_library_map__.php' failed!");
}
}
return $this->libraryMaps[$name];
}
public function getLibraryRoot($name) {
if (empty($this->registeredLibraries[$name])) {
throw new PhutilBootloaderException(
"The phutil library '{$name}' has not been loaded!");
}
return $this->registeredLibraries[$name];
}
public function getAllLibraries() {
return array_keys($this->registeredLibraries);
}
private function pushModuleStack($library, $module) {
array_push($this->moduleStack, $this->getLibraryRoot($library).'/'.$module);
return $this;
}
private function popModuleStack() {
array_pop($this->moduleStack);
}
private function peekModuleStack() {
return end($this->moduleStack);
}
public function loadLibrary($path) {
$root = null;
if (!empty($_SERVER['PHUTIL_LIBRARY_ROOT'])) {
if ($path[0] != '/') {
$root = $_SERVER['PHUTIL_LIBRARY_ROOT'];
}
}
$okay = $this->executeInclude($root.$path.'/__phutil_library_init__.php');
if (!$okay) {
throw new PhutilBootloaderException(
"Include of '{$path}/__phutil_library_init__.php' failed!");
}
}
public function loadModule($library, $module) {
$this->pushModuleStack($library, $module);
phutil_require_source('__init__.php');
$this->popModuleStack();
}
public function loadSource($source) {
$base = $this->peekModuleStack();
$okay = $this->executeInclude($base.'/'.$source);
if (!$okay) {
throw new PhutilBootloaderException(
"Include of '{$base}/{$source}' failed!");
}
}
public function moduleExists($library, $module) {
$path = $this->getLibraryRoot($library);
return @file_exists($path.'/'.$module.'/__init__.php');
}
private function executeInclude($path) {
// Suppress warning spew if the file does not exist; we'll throw an
// exception instead. We still emit error text in the case of syntax errors.
$old = error_reporting(E_ALL & ~E_WARNING);
$okay = include_once $path;
error_reporting($old);
return $okay;
}
}
/**
* @group library
*/
final class PhutilBootloaderException extends Exception { }
/**
* Thrown when you attempt to load two different copies of a library with the
* same name. Trying to load the second copy of the library will trigger this,
* and the library will not be loaded.
*
* This means you've either done something silly (like tried to explicitly load
* two different versions of the same library into the same program -- this
* won't work because they'll have namespace conflicts), or your configuration
* might have some problems which caused two parts of your program to try to
* load the same library but end up loading different copies of it, or there
* may be some subtle issue like running 'arc' in a different Arcanist working
* directory. (Some bootstrapping workflows like that which run low-level
* library components on other copies of themselves are expected to fail.)
*
* To resolve this, you need to make sure your program loads no more than one
* copy of each libphutil library, but exactly how you approach this depends on
* why it's happening in the first place.
*
* @task info Getting Exception Information
* @task construct Creating Library Conflict Exceptions
* @group library
*/
final class PhutilLibraryConflictException extends Exception {
private $library;
private $oldPath;
private $newPath;
/**
* Create a new library conflict exception.
*
* @param string The name of the library which conflicts with an existing
* library.
* @param string The path of the already-loaded library.
* @param string The path of the attempting-to-load library.
*
* @task construct
*/
public function __construct($library, $old_path, $new_path) {
$this->library = $library;
$this->oldPath = $old_path;
$this->newPath = $new_path;
$message = "Library conflict! The library '{$library}' has already been ".
"loaded (from '{$old_path}') but is now being loaded again ".
"from a new location ('{$new_path}'). You can not load ".
"multiple copies of the same library into a program.";
parent::__construct($message);
}
/**
* Retrieve the name of the library in conflict.
*
* @return string The name of the library which conflicts with an existing
* library.
* @task info
*/
public function getLibrary() {
return $this->library;
}
/**
* Get the path to the library which has already been loaded earlier in the
* program's execution.
*
* @return string The path of the already-loaded library.
* @task info
*/
public function getOldPath() {
return $this->oldPath;
}
/**
* Get the path to the library which is causing this conflict.
*
* @return string The path of the attempting-to-load library.
* @task info
*/
public function getNewPath() {
return $this->newPath;
}
}
phutil_register_library('phutil', __FILE__);
phutil_require_module('phutil', 'symbols');
/**
* @group library
*/
function __phutil_autoload($class) {
try {
PhutilSymbolLoader::loadClass($class);
} catch (PhutilMissingSymbolException $ex) {
// If there are other SPL autoloaders installed, we need to give them a
// chance to load the class. Throw the exception if we're the last
// autoloader; if not, swallow it and let them take a shot.
$autoloaders = spl_autoload_functions();
$last = end($autoloaders);
if ($last == '__phutil_autoload') {
throw $ex;
}
}
}
spl_autoload_register('__phutil_autoload', $throw = true);
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