composer 类加载器,对 <PSR-4的风格>、<PSR-0的风格>、<PEAR的风格> 风格的类的加载
class ClassLoader { // ... /** * composer 类加载器,对 <PSR-4的风格>、<PSR-0的风格>、<PEAR的风格> 风格的类的加载 */ private function findFileWithExtension($class, $ext) { // PSR-4 lookup <PSR-4的风格>: Dir1\Dir2\ClassName1 ---> Dir1/Dir2/ClassName1 $logicalPathPsr4 = strtr($class, '\\', DIRECTORY_SEPARATOR) . $ext; $first = $class[0]; if (isset($this->prefixLengthsPsr4[$first])) { foreach ($this->prefixLengthsPsr4[$first] as $prefix => $length) { if (0 === strpos($class, $prefix)) { foreach ($this->prefixDirsPsr4[$prefix] as $dir) { if (file_exists($file = $dir . DIRECTORY_SEPARATOR . substr($logicalPathPsr4, $length))) { return $file; } } } } } // PSR-4 fallback dirs 匹配失败 foreach ($this->fallbackDirsPsr4 as $dir) { if (file_exists($file = $dir . DIRECTORY_SEPARATOR . $logicalPathPsr4)) { return $file; } } // PSR-0 lookup <PSR-0的风格>: Dir1\Dir2\Dir3_ClassName1 ---> Dir1\Dir2/ClassName1 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 <PEAR的风格>: Dir1_Dir2_ClassName1 --->Dir1/Dir2/ClassName1 $logicalPathPsr0 = strtr($class, '_', DIRECTORY_SEPARATOR) . $ext; } if (isset($this->prefixesPsr0[$first])) { foreach ($this->prefixesPsr0[$first] as $prefix => $dirs) { if (0 === strpos($class, $prefix)) { foreach ($dirs as $dir) { if (file_exists($file = $dir . DIRECTORY_SEPARATOR . $logicalPathPsr0)) { return $file; } } } } } // PSR-0 fallback dirs foreach ($this->fallbackDirsPsr0 as $dir) { if (file_exists($file = $dir . DIRECTORY_SEPARATOR . $logicalPathPsr0)) { return $file; } } // PSR-0 include paths. if ($this->useIncludePath && $file = stream_resolve_include_path($logicalPathPsr0)) { return $file; } } // ... }