<code>class PHPExcel_Shared_File { protected static $_useUploadTempDirectory = FALSE; public static function sys_get_temp_dir() { if (self::$_useUploadTempDirectory) { // use upload-directory when defined to allow running on environments having very restricted // open_basedir configs if (ini_get('upload_tmp_dir') !== FALSE) { if ($temp = ini_get('upload_tmp_dir')) { if (file_exists($temp)) return realpath($temp); } } } // sys_get_temp_dir is only available since PHP 5.2.1 // http://php.net/manual/en/function.sys-get-temp-dir.php#94119 if ( !function_exists('sys_get_temp_dir')) { if ($temp = getenv('TMP') ) { if ((!empty($temp)) && (file_exists($temp))) { return realpath($temp); } } if ($temp = getenv('TEMP') ) { if ((!empty($temp)) && (file_exists($temp))) { return realpath($temp); } } if ($temp = getenv('TMPDIR') ) { if ((!empty($temp)) && (file_exists($temp))) { return realpath($temp); } } // trick for creating a file in system's temporary dir // without knowing the path of the system's temporary dir $temp = tempnam(__FILE__, ''); if (file_exists($temp)) { unlink($temp); return realpath(dirname($temp)); } return null; } // use ordinary built-in PHP function // There should be no problem with the 5.2.4 Suhosin realpath() bug, because this line should only // be called if we're running 5.2.1 or earlier return realpath(sys_get_temp_dir()); } } }</code>
这是摘出来的一段代码。两个问题
1:protected static $_useUploadTempDirectory = FALSE; 恒假,那么if (self::$_useUploadTempDirectory)这个判断就不成立,为什么还要写这个if语句呢?
2:if ( !function_exists('sys_get_temp_dir')) 这个if语句就在sys_get_temp_dir函数中,也就是说这个函数一直存在啊?? 那么下面的语句也就不会执行了啊
不知道我理解的对不对?? 这个也算是一个比较成熟的cms里的代码了。。 为什么会这么写呢??
回复内容:
<code>class PHPExcel_Shared_File { protected static $_useUploadTempDirectory = FALSE; public static function sys_get_temp_dir() { if (self::$_useUploadTempDirectory) { // use upload-directory when defined to allow running on environments having very restricted // open_basedir configs if (ini_get('upload_tmp_dir') !== FALSE) { if ($temp = ini_get('upload_tmp_dir')) { if (file_exists($temp)) return realpath($temp); } } } // sys_get_temp_dir is only available since PHP 5.2.1 // http://php.net/manual/en/function.sys-get-temp-dir.php#94119 if ( !function_exists('sys_get_temp_dir')) { if ($temp = getenv('TMP') ) { if ((!empty($temp)) && (file_exists($temp))) { return realpath($temp); } } if ($temp = getenv('TEMP') ) { if ((!empty($temp)) && (file_exists($temp))) { return realpath($temp); } } if ($temp = getenv('TMPDIR') ) { if ((!empty($temp)) && (file_exists($temp))) { return realpath($temp); } } // trick for creating a file in system's temporary dir // without knowing the path of the system's temporary dir $temp = tempnam(__FILE__, ''); if (file_exists($temp)) { unlink($temp); return realpath(dirname($temp)); } return null; } // use ordinary built-in PHP function // There should be no problem with the 5.2.4 Suhosin realpath() bug, because this line should only // be called if we're running 5.2.1 or earlier return realpath(sys_get_temp_dir()); } } }</code>
这是摘出来的一段代码。两个问题
1:protected static $_useUploadTempDirectory = FALSE; 恒假,那么if (self::$_useUploadTempDirectory)这个判断就不成立,为什么还要写这个if语句呢?
2:if ( !function_exists('sys_get_temp_dir')) 这个if语句就在sys_get_temp_dir函数中,也就是说这个函数一直存在啊?? 那么下面的语句也就不会执行了啊
不知道我理解的对不对?? 这个也算是一个比较成熟的cms里的代码了。。 为什么会这么写呢??
1 static 只是静态 ,但是可以被修改的
2 sys_get_temp_dir 指的是php系统自带的函数,而不是类中的函数
有没有想过,它的继承类可能把$_useUploadTempDirectory设成true?

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