-
把loader主要的功能提取出来，从属性和方法着手，大致可以分为这些
-
上图说明一切
-
接下来我们就要刨根问底，走进去看看Loader类里面到底是个什么鬼
-
附上源码
<?php
namespace think;
use think\exception\ClassNotFoundException;
class Loader
{
/**
* 类名映射信息
* @var array
*/
protected static $classMap = [];
/**
* 类库别名
* @var array
*/
protected static $classAlias = [];
/**
* PSR-4
* @var array
*/
private static $prefixLengthsPsr4 = [];
private static $prefixDirsPsr4 = [];
private static $fallbackDirsPsr4 = [];
/**
* PSR-0
* @var array
*/
private static $prefixesPsr0 = [];
private static $fallbackDirsPsr0 = [];
/**
* 需要加载的文件
* @var array
*/
private static $files = [];
/**
* Composer安装路径
* @var string
*/
private static $composerPath;
// 获取应用根目录
public static function getRootPath()
{
if ('cli' == PHP_SAPI) {
$scriptName = realpath($_SERVER['argv'][0]);
} else {
$scriptName = $_SERVER['SCRIPT_FILENAME'];
}
$path = realpath(dirname($scriptName));
if (!is_file($path . DIRECTORY_SEPARATOR . 'think')) {
$path = dirname($path);
}
return $path . DIRECTORY_SEPARATOR;
}
// 注册自动加载机制
public static function register($autoload = '')
{
// 注册系统自动加载
spl_autoload_register($autoload ?: 'think\\Loader::autoload', true, true);
$rootPath = self::getRootPath();
self::$composerPath = $rootPath . 'vendor' . DIRECTORY_SEPARATOR . 'composer' . DIRECTORY_SEPARATOR;
// Composer自动加载支持
if (is_dir(self::$composerPath)) {
if (is_file(self::$composerPath . 'autoload_static.php')) {
require self::$composerPath . 'autoload_static.php';
// require $rootPath.'extend/Liangzai.php';
$declaredClass = get_declared_classes();
$composerClass = array_pop($declaredClass);
foreach (['prefixLengthsPsr4', 'prefixDirsPsr4', 'fallbackDirsPsr4', 'prefixesPsr0', 'fallbackDirsPsr0', 'classMap', 'files'] as $attr) {
if (property_exists($composerClass, $attr)) {
self::${$attr} = $composerClass::${$attr};
}
}
} else {
self::registerComposerLoader(self::$composerPath);
}
}
// 注册命名空间定义
self::addNamespace([
'think' => __DIR__,
'traits' => dirname(__DIR__) . DIRECTORY_SEPARATOR . 'traits',
]);
// 加载类库映射文件
if (is_file($rootPath . 'runtime' . DIRECTORY_SEPARATOR . 'classmap.php')) {
self::addClassMap(__include_file($rootPath . 'runtime' . DIRECTORY_SEPARATOR . 'classmap.php'));
}
// 自动加载extend目录
self::addAutoLoadDir($rootPath . 'extend');
}
// 自动加载
public static function autoload($class)
{
// echo $class;
// echo '<br>';
//返回别名
if (isset(self::$classAlias[$class])) {
echo 4;
return class_alias(self::$classAlias[$class], $class);
}
echo 5;
if ($file = self::findFile($class)) {
// Win环境严格区分大小写
if (strpos(PHP_OS, 'WIN') !== false && pathinfo($file, PATHINFO_FILENAME) != pathinfo(realpath($file), PATHINFO_FILENAME)) {
return false;
}
__include_file($file);
return true;
}
}
/**
* 查找文件
* @access private
* @param string $class
* @return string|false
*/
private static function findFile($class)
{
if (!empty(self::$classMap[$class])) {
// 类库映射
return self::$classMap[$class];
}
// 查找 PSR-4
$logicalPathPsr4 = strtr($class, '\\', DIRECTORY_SEPARATOR) . '.php';
// echo $class;
// echo '</br>';
$first = $class[0];// think\Response t 取出第一个字母
if (isset(self::$prefixLengthsPsr4[$first])) {
foreach (self::$prefixLengthsPsr4[$first] as $prefix => $length) {
if (0 === strpos($class, $prefix)) {
foreach (self::$prefixDirsPsr4[$prefix] as $dir) {
if (is_file($file = $dir . DIRECTORY_SEPARATOR . substr($logicalPathPsr4, $length))) {
return $file;
}
}
}
}
}
// 查找 PSR-4 fallback dirs
foreach (self::$fallbackDirsPsr4 as $dir) {
if (is_file($file = $dir . DIRECTORY_SEPARATOR . $logicalPathPsr4)) {
return $file;
}
}
// 查找 PSR-0
if (false !== $pos = strrpos($class, '\\')) {
// namespaced class name
$logicalPathPsr0 = substr($logicalPathPsr4, 0, $pos + 1)
. strtr(substr($logicalPathPsr4, $pos + 1), '_', DIRECTORY_SEPARATOR);
} else {
// PEAR-like class name
$logicalPathPsr0 = strtr($class, '_', DIRECTORY_SEPARATOR) . '.php';
}
if (isset(self::$prefixesPsr0[$first])) {
foreach (self::$prefixesPsr0[$first] as $prefix => $dirs) {
if (0 === strpos($class, $prefix)) {
foreach ($dirs as $dir) {
if (is_file($file = $dir . DIRECTORY_SEPARATOR . $logicalPathPsr0)) {
return $file;
}
}
}
}
}
// 查找 PSR-0 fallback dirs
foreach (self::$fallbackDirsPsr0 as $dir) {
if (is_file($file = $dir . DIRECTORY_SEPARATOR . $logicalPathPsr0)) {
return $file;
}
}
return self::$classMap[$class] = false;
}
// 注册classmap
public static function addClassMap($class, $map = '')
{
if (is_array($class)) {
self::$classMap = array_merge(self::$classMap, $class);
} else {
self::$classMap[$class] = $map;
}
}
// 注册命名空间
public static function addNamespace($namespace, $path = '')
{
if (is_array($namespace)) {
foreach ($namespace as $prefix => $paths) {
self::addPsr4($prefix . '\\', rtrim($paths, DIRECTORY_SEPARATOR), true);
}
} else {
self::addPsr4($namespace . '\\', rtrim($path, DIRECTORY_SEPARATOR), true);
}
}
// 添加Ps0空间
private static function addPsr0($prefix, $paths, $prepend = false)
{
if (!$prefix) {
if ($prepend) {
self::$fallbackDirsPsr0 = array_merge(
(array) $paths,
self::$fallbackDirsPsr0
);
} else {
self::$fallbackDirsPsr0 = array_merge(
self::$fallbackDirsPsr0,
(array) $paths
);
}
return;
}
$first = $prefix[0];
if (!isset(self::$prefixesPsr0[$first][$prefix])) {
self::$prefixesPsr0[$first][$prefix] = (array) $paths;
return;
}
if ($prepend) {
self::$prefixesPsr0[$first][$prefix] = array_merge(
(array) $paths,
self::$prefixesPsr0[$first][$prefix]
);
} else {
self::$prefixesPsr0[$first][$prefix] = array_merge(
self::$prefixesPsr0[$first][$prefix],
(array) $paths
);
}
}
// 添加Psr4空间
private static function addPsr4($prefix, $paths, $prepend = false)
{
if (!$prefix) {
// Register directories for the root namespace.
if ($prepend) {
self::$fallbackDirsPsr4 = array_merge(
(array) $paths,
self::$fallbackDirsPsr4
);
} else {
self::$fallbackDirsPsr4 = array_merge(
self::$fallbackDirsPsr4,
(array) $paths
);
}
} elseif (!isset(self::$prefixDirsPsr4[$prefix])) {
// Register directories for a new namespace.
$length = strlen($prefix);
if ('\\' !== $prefix[$length - 1]) {
throw new \InvalidArgumentException("A non-empty PSR-4 prefix must end with a namespace separator.");
}
self::$prefixLengthsPsr4[$prefix[0]][$prefix] = $length;
self::$prefixDirsPsr4[$prefix] = (array) $paths;
} elseif ($prepend) {
// Prepend directories for an already registered namespace.
self::$prefixDirsPsr4[$prefix] = array_merge(
(array) $paths,
self::$prefixDirsPsr4[$prefix]
);
} else {
// Append directories for an already registered namespace.
self::$prefixDirsPsr4[$prefix] = array_merge(
self::$prefixDirsPsr4[$prefix],
(array) $paths
);
}
}
// 注册自动加载类库目录
public static function addAutoLoadDir($path)
{
self::$fallbackDirsPsr4[] = $path;
}
// 注册类别名
public static function addClassAlias($alias, $class = null)
{
if (is_array($alias)) {
self::$classAlias = array_merge(self::$classAlias, $alias);
} else {
self::$classAlias[$alias] = $class;
}
}
// 注册composer自动加载
public static function registerComposerLoader($composerPath)
{
if (is_file($composerPath . 'autoload_namespaces.php')) {
$map = require $composerPath . 'autoload_namespaces.php';
foreach ($map as $namespace => $path) {
self::addPsr0($namespace, $path);
}
}
if (is_file($composerPath . 'autoload_psr4.php')) {
$map = require $composerPath . 'autoload_psr4.php';
foreach ($map as $namespace => $path) {
self::addPsr4($namespace, $path);
}
}
if (is_file($composerPath . 'autoload_classmap.php')) {
$classMap = require $composerPath . 'autoload_classmap.php';
if ($classMap) {
self::addClassMap($classMap);
}
}
if (is_file($composerPath . 'autoload_files.php')) {
self::$files = require $composerPath . 'autoload_files.php';
}
}
// 加载composer autofile文件
public static function loadComposerAutoloadFiles()
{
foreach (self::$files as $fileIdentifier => $file) {
if (empty($GLOBALS['__composer_autoload_files'][$fileIdentifier])) {
__require_file($file);
$GLOBALS['__composer_autoload_files'][$fileIdentifier] = true;
}
}
}
/**
* 字符串命名风格转换
* type 0 将Java风格转换为C的风格 1 将C风格转换为Java的风格
* @access public
* @param string $name 字符串
* @param integer $type 转换类型
* @param bool $ucfirst 首字母是否大写（驼峰规则）
* @return string
*/
public static function parseName($name, $type = 0, $ucfirst = true)
{
if ($type) {
$name = preg_replace_callback('/_([a-zA-Z])/', function ($match) {
return strtoupper($match[1]);
}, $name);
return $ucfirst ? ucfirst($name) : lcfirst($name);
}
return strtolower(trim(preg_replace("/[A-Z]/", "_\\0", $name), "_"));
}
/**
* 创建工厂对象实例
* @access public
* @param string $name 工厂类名
* @param string $namespace 默认命名空间
* @return mixed
*/
public static function factory($name, $namespace = '', ...$args)
{
$class = false !== strpos($name, '\\') ? $name : $namespace . ucwords($name);
if (class_exists($class)) {
return Container::getInstance()->invokeClass($class, $args);
} else {
throw new ClassNotFoundException('class not exists:' . $class, $class);
}
}
}
/**
* 作用范围隔离
*
* @param $file
* @return mixed
*/
function __include_file($file)
{
return include $file;
}
function __require_file($file)
{
return require $file;
}