一个非常完美的读写ini格式的PHP配置类分享

            基本满足所有配置相关的需求。
/**
* 解析.ini格式的配置文件为一个树形结构的对象
* 配置文件不同section通过冒号继承
* 默认根据hostname确定使用的section，如果不能确定就优先使用production
* 检测环境的时候总是优先检测production，其余section按定义顺序检测
*
* @author ares@phpdr.net
*   
*/
class Config {
/**
* 解析后的配置文件
*
* @var stdClass
*/
private $config;
/**
* 一个二维数组，键是配置文件的section
* 值是一个数组或回调函数
* 如果是数组则计算hostname是否在数组中决定是否使用该section
* 如果是回调函数通过返回值true或false来确定是否使用该section
*
* @var array
*/
private $map = array ();

/**
* section会被解析，:表示继承
* 配置项中的'.'用来区分层级关系
* section中的'.'不会被解析，配置中的数组不受影响。
*
* @param string $conf     
* @throws ErrorException
* @return stdClass
*/
function __construct($conf, $map) {
$config = $this->parseIni ( ( object ) parse_ini_string ( $conf, true ) );
if (array_key_exists ( 'production', $map )) {
  $production = $map ['production'];
  unset ( $map ['production'] );
  $map = array_merge ( array (
   'production' => $production ), $map );
} else {
  throw new ErrorException ( 'production section not found in config' );
}
$section = 'production';
$hostname = gethostname ();
foreach ( $map as $k => $v ) {
  if (is_array ( $v )) {
  foreach ( $v as $v1 ) {
   if ($v1 == $hostname) {
   $section = $k;
   break 2;
   }
  }
  } elseif (is_callable ( $v )) {
  if (true == call_user_func ( $v )) {
   $section = $k;
   break;
  }
  } else {
  throw new ErrorException ( 'Wrong map value in ' . __CLASS__ );
  }
}
$this->config = $config->$section;
}

/**
* 总是返回配置对象
*
* @return mixed
*/
function __get($key) {
if (isset ( $this->config->$key )) {
  return $this->config->$key;
}
}

/**
* 切分
*
* @param stdClass $v     
* @param string $k1     
* @param mixed $v1     
*/
private function split($v, $k1, $v1) {
$keys = explode ( '.', $k1 );
$last = array_pop ( $keys );
$node = $v;
foreach ( $keys as $v2 ) {
  if (! isset ( $node->$v2 )) {
  $node->$v2 = new stdClass ();
  }
  $node = $node->$v2;
}
$node->$last = $v1;
if (count ( $keys ) > 0) {
  unset ( $v->$k1 );
}
}

/**
* parseIni
*
* @param object $conf     
* @return stdClass
*/
private function parseIni($conf) {
$confObj = new stdClass ();
foreach ( $conf as $k => $v ) {
  // 是section
  if (is_array ( $v )) {
  $confObj->$k = ( object ) $v;
  foreach ( $v as $k1 => $v1 ) {
   call_user_func ( array (
    $this,
    'split' ), $confObj->$k, $k1, $v1 );
  }
  } else {
  call_user_func ( array (
   $this,
   'split' ), $confObj, $k, $v );
  }
}
unset ( $conf );
// 处理继承
foreach ( $confObj as $k => $v ) {
  if (false !== strpos ( $k, ':' )) {
  if (0 === strpos ( $k, ':' )) {
   throw new ErrorException ( 'config ' . $k . ' is invalid, ':' can't be the first char' );
  } elseif (1 $keys [1] )) {
   throw new ErrorException ( 'parent section ' . $keys [1] . ' doesn't exist in config file' );
   } else {
   if (isset ( $confObj->$keys [0] )) {
    throw new ErrorException ( 'config is invalid, ' . $keys [0] . ' and ' . $k . ' conflicts' );
   } else {
    $confObj->$keys [0] = $this->deepCloneR ( $confObj->$keys [1] );
    $this->objectMergeR ( $confObj->$keys [0], $v );
    unset ( $confObj->$k );
   }
   }
  }
  }
}
return $confObj;
}

/**
* php默认是浅克隆，函数实现深克隆
*
* @param object $obj     
* @return object $obj
*/
private function deepCloneR($obj) {
$objClone = clone $obj;
foreach ( $objClone as $k => $v ) {
  if (is_object ( $v )) {
  $objClone->$k = $this->deepCloneR ( $v );
  }
}
return $objClone;
}

/**
* 递归的合并两个对象
*
* @param unknown $obj1     
* @param unknown $obj2     
*/
private function objectMergeR($obj1, $obj2) {
foreach ( $obj2 as $k => $v ) {
  if (is_object ( $v ) && isset ( $obj1->$k ) && is_object ( $obj1->$k )) {
  $this->objectMergeR ( $obj1->$k, $v );
  } else {
  $obj1->$k = $v;
  }
}
}
}
简单使用：
$_ENV ['config'] = new Config ( file_get_contents ( __DIR__ . '/config.ini' ), array (
'development' => array (
  'localhost.localdomain',
  'localhost'
),
'production' => array ()
) );
配置文件示例：
[product]
db.default.dsn="mysql:host=127.0.0.1;dbname=default"
db.default.username=root
db.default.password=123456
admin.username=admin
admin.password=123456
php.error_reporting=E_ALL
php.display_errors=no
php.log_errors=yes
php.error_log=APP_PATH'/resource/log/phpError.log'
php.session.save_path=APP_PATH'/resource/data/session'
[development:product]
db.test1.dsn="mysql:host=127.0.0.1;dbname=test1"
db.test1.username=root
db.test1.password=123456
php.display_errors=yes