PHP function_usable函数代码示例

 public function common_functions()
 {
     echo is_php('5.3');
     echo is_really_writable('file.php');
     echo config_item('key');
     echo set_status_header('200', 'text');
     echo remove_invisible_characters('Java\\0script');
     echo html_escape(array());
     echo get_mimes();
     echo is_https();
     echo is_cli();
     echo function_usable('eval');
 }

 /**
  * Image Process Using NetPBM
  *
  * This function will resize, crop or rotate
  *
  * @param  string
  * @return  bool
  */
 public function image_process_netpbm($action = 'resize')
 {
     if ($this->library_path === '') {
         $this->set_error('imglib_libpath_invalid');
         return FALSE;
     }
     // Build the resizing command
     switch ($this->image_type) {
         case 1:
             $cmd_in = 'giftopnm';
             $cmd_out = 'ppmtogif';
             break;
         case 2:
             $cmd_in = 'jpegtopnm';
             $cmd_out = 'ppmtojpeg';
             break;
         case 3:
             $cmd_in = 'pngtopnm';
             $cmd_out = 'ppmtopng';
             break;
     }
     if ($action === 'crop') {
         $cmd_inner = 'pnmcut -left ' . $this->x_axis . ' -top ' . $this->y_axis . ' -width ' . $this->width . ' -height ' . $this->height;
     } elseif ($action === 'rotate') {
         switch ($this->rotation_angle) {
             case 90:
                 $angle = 'r270';
                 break;
             case 180:
                 $angle = 'r180';
                 break;
             case 270:
                 $angle = 'r90';
                 break;
             case 'vrt':
                 $angle = 'tb';
                 break;
             case 'hor':
                 $angle = 'lr';
                 break;
         }
         $cmd_inner = 'pnmflip -' . $angle . ' ';
     } else {
         $cmd_inner = 'pnmscale -xysize ' . $this->width . ' ' . $this->height;
     }
     $cmd = $this->library_path . $cmd_in . ' ' . $this->full_src_path . ' | ' . $cmd_inner . ' | ' . $cmd_out . ' > ' . $this->dest_folder . 'netpbm.tmp';
     $retval = 1;
     // exec() might be disabled
     if (function_usable('exec')) {
         @exec($cmd, $output, $retval);
     }
     // Did it work?
     if ($retval > 0) {
         $this->set_error('imglib_image_process_failed');
         return FALSE;
     }
     // With NetPBM we have to create a temporary image.
     // If you try manipulating the original it fails so
     // we have to rename the temp file.
     copy($this->dest_folder . 'netpbm.tmp', $this->full_dst_path);
     unlink($this->dest_folder . 'netpbm.tmp');
     chmod($this->full_dst_path, $this->file_permissions);
     return TRUE;
 }

 /**
  * File MIME type
  *
  * Detects the (actual) MIME type of the uploaded file, if possible.
  * The input array is expected to be $_FILES[$field]
  *
  * @param  array $file
  * @return  void
  */
 protected function _file_mime_type($file)
 {
     // We'll need this to validate the MIME info string (e.g. text/plain; charset=us-ascii)
     $regexp = '/^([a-z\\-]+\\/[a-z0-9\\-\\.\\+]+)(;\\s.+)?$/';
     /* Fileinfo extension - most reliable method
      *
      * Unfortunately, prior to PHP 5.3 - it's only available as a PECL extension and the
      * more convenient FILEINFO_MIME_TYPE flag doesn't exist.
      */
     if (function_exists('finfo_file')) {
         $finfo = @finfo_open(FILEINFO_MIME);
         if (is_resource($finfo)) {
             $mime = @finfo_file($finfo, $file['tmp_name']);
             finfo_close($finfo);
             /* According to the comments section of the PHP manual page,
              * it is possible that this function returns an empty string
              * for some files (e.g. if they don't exist in the magic MIME database)
              */
             if (is_string($mime) && preg_match($regexp, $mime, $matches)) {
                 $this->file_type = $matches[1];
                 return;
             }
         }
     }
     /* This is an ugly hack, but UNIX-type systems provide a "native" way to detect the file type,
      * which is still more secure than depending on the value of $_FILES[$field]['type'], and as it
      * was reported in issue #750 (https://github.com/EllisLab/CodeIgniter/issues/750) - it's better
      * than mime_content_type() as well, hence the attempts to try calling the command line with
      * three different functions.
      *
      * Notes:
      *	- the DIRECTORY_SEPARATOR comparison ensures that we're not on a Windows system
      *	- many system admins would disable the exec(), shell_exec(), popen() and similar functions
      *	  due to security concerns, hence the function_usable() checks
      */
     if (DIRECTORY_SEPARATOR !== '\\') {
         $cmd = function_exists('escapeshellarg') ? 'file --brief --mime ' . escapeshellarg($file['tmp_name']) . ' 2>&1' : 'file --brief --mime ' . $file['tmp_name'] . ' 2>&1';
         if (function_usable('exec')) {
             /* This might look confusing, as $mime is being populated with all of the output when set in the second parameter.
              * However, we only need the last line, which is the actual return value of exec(), and as such - it overwrites
              * anything that could already be set for $mime previously. This effectively makes the second parameter a dummy
              * value, which is only put to allow us to get the return status code.
              */
             $mime = @exec($cmd, $mime, $return_status);
             if ($return_status === 0 && is_string($mime) && preg_match($regexp, $mime, $matches)) {
                 $this->file_type = $matches[1];
                 return;
             }
         }
         if (!ini_get('safe_mode') && function_usable('shell_exec')) {
             $mime = @shell_exec($cmd);
             if (strlen($mime) > 0) {
                 $mime = explode("\n", trim($mime));
                 if (preg_match($regexp, $mime[count($mime) - 1], $matches)) {
                     $this->file_type = $matches[1];
                     return;
                 }
             }
         }
         if (function_usable('popen')) {
             $proc = @popen($cmd, 'r');
             if (is_resource($proc)) {
                 $mime = @fread($proc, 512);
                 @pclose($proc);
                 if ($mime !== FALSE) {
                     $mime = explode("\n", trim($mime));
                     if (preg_match($regexp, $mime[count($mime) - 1], $matches)) {
                         $this->file_type = $matches[1];
                         return;
                     }
                 }
             }
         }
     }
     // Fall back to the deprecated mime_content_type(), if available (still better than $_FILES[$field]['type'])
     if (function_exists('mime_content_type')) {
         $this->file_type = @mime_content_type($file['tmp_name']);
         if (strlen($this->file_type) > 0) {
             return;
         }
     }
     $this->file_type = $file['type'];
 }

 /**
  * Send using Sendmail
  *
  * @return	bool
  */
 protected function _send_with_sendmail()
 {
     // is popen() enabled?
     if (!function_usable('popen') or FALSE === ($fp = @popen($this->mailpath . ' -oi -f ' . $this->clean_email($this->_headers['From']) . ' -t -r ' . $this->clean_email($this->_headers['Return-Path']), 'w'))) {
         return FALSE;
     }
     fputs($fp, $this->_header_str);
     fputs($fp, $this->_finalbody);
     $status = pclose($fp);
     if ($status !== 0) {
         $this->_set_error_message('lang:email_exit_status', $status);
         $this->_set_error_message('lang:email_no_socket');
         return FALSE;
     }
     return TRUE;
 }

function isWindowsNT()
{
    static $winnt;
    if (isset($winnt)) {
        return $winnt;
    }
    // FIXME: Do this using PHP_OS instead of php_uname().
    // $winnt = (PHP_OS == "WINNT"); // example from http://www.php.net/manual/en/ref.readline.php
    if (function_usable('php_uname')) {
        $winnt = preg_match('/^Windows NT/', php_uname());
    } else {
        $winnt = false;
    }
    // FIXME: punt.
    return $winnt;
}

 /**
  * Internal CI Data Loader
  *
  * Used to load views and files.
  *
  * Variables are prefixed with _ci_ to avoid symbol collision with
  * variables made available to view files.
  *
  * @used-by	CI_Loader::view()
  * @used-by	CI_Loader::file()
  * @param	array	$_ci_data	Data to load
  * @return	object
  */
 protected function _ci_load($_ci_data)
 {
     // Set the default data variables
     foreach (array('_ci_view', '_ci_vars', '_ci_path', '_ci_return') as $_ci_val) {
         ${$_ci_val} = isset($_ci_data[$_ci_val]) ? $_ci_data[$_ci_val] : FALSE;
     }
     $file_exists = FALSE;
     // Set the path to the requested file
     if (is_string($_ci_path) && $_ci_path !== '') {
         $_ci_x = explode('/', $_ci_path);
         $_ci_file = end($_ci_x);
     } else {
         $_ci_ext = pathinfo($_ci_view, PATHINFO_EXTENSION);
         $_ci_file = $_ci_ext === '' ? $_ci_view . '.php' : $_ci_view;
         foreach ($this->_ci_view_paths as $_ci_view_file => $cascade) {
             if (file_exists($_ci_view_file . $_ci_file)) {
                 $_ci_path = $_ci_view_file . $_ci_file;
                 $file_exists = TRUE;
                 break;
             }
             if (!$cascade) {
                 break;
             }
         }
     }
     if (!$file_exists && !file_exists($_ci_path)) {
         show_error('Unable to load the requested file: ' . $_ci_file);
     }
     // This allows anything loaded using $this->load (views, files, etc.)
     // to become accessible from within the Controller and Model functions.
     $_ci_CI =& get_instance();
     foreach (get_object_vars($_ci_CI) as $_ci_key => $_ci_var) {
         if (!isset($this->{$_ci_key})) {
             $this->{$_ci_key} =& $_ci_CI->{$_ci_key};
         }
     }
     /*
      * Extract and cache variables
      *
      * You can either set variables using the dedicated $this->load->vars()
      * function or via the second parameter of this function. We'll merge
      * the two types and cache them so that views that are embedded within
      * other views can have access to these variables.
      */
     if (is_array($_ci_vars)) {
         $this->_ci_cached_vars = array_merge($this->_ci_cached_vars, $_ci_vars);
     }
     extract($this->_ci_cached_vars);
     /*
      * Buffer the output
      *
      * We buffer the output for two reasons:
      * 1. Speed. You get a significant speed boost.
      * 2. So that the final rendered template can be post-processed by
      *	the output class. Why do we need post processing? For one thing,
      *	in order to show the elapsed page load time. Unless we can
      *	intercept the content right before it's sent to the browser and
      *	then stop the timer it won't be accurate.
      */
     ob_start();
     // If the PHP installation does not support short tags we'll
     // do a little string replacement, changing the short tags
     // to standard PHP echo statements.
     if (!is_php('5.4') && !ini_get('short_open_tag') && config_item('rewrite_short_tags') === TRUE && function_usable('eval')) {
         echo eval('?>' . preg_replace('/;*\\s*\\?>/', '; ?>', str_replace('<?=', '<?php echo ', file_get_contents($_ci_path))));
     } else {
         include $_ci_path;
         // include() vs include_once() allows for multiple views with the same name
     }
     log_message('info', 'File loaded: ' . $_ci_path);
     // Return the file data if requested
     if ($_ci_return === TRUE) {
         $buffer = ob_get_contents();
         @ob_end_clean();
         return $buffer;
     }
     /*
      * Flush the buffer... or buff the flusher?
      *
      * In order to permit views to be nested within
      * other views, we need to flush the content back out whenever
      * we are beyond the first level of output buffering so that
      * it can be seen and included properly by the first included
      * template and any subsequent ones. Oy!
      */
     if (ob_get_level() > $this->_ci_ob_level + 1) {
         ob_end_flush();
//.........这里部分代码省略.........

 public function render()
 {
     if (!empty($this->image)) {
         if (isset($this->_template)) {
             $vars = get_object_vars($this);
             extract($vars);
             ob_start();
             // If the PHP installation does not support short tags we'll
             // do a little string replacement, changing the short tags
             // to standard PHP echo statements.
             if (!ini_get('short_open_tag') and function_usable('eval')) {
                 echo eval('?>' . preg_replace('/;*\\s*\\?>/', '; ?>', str_replace('<?=', '<?php echo ', $this->_template)));
             } else {
                 echo eval('?>' . preg_replace('/;*\\s*\\?>/', '; ?>', $this->_template));
             }
             $output = ob_get_contents();
             ob_end_clean();
             return $output;
         } else {
             if (isset($this->link)) {
                 $output[] = new Link($this->image, $this->link);
                 $caption = new Link($this->caption, $this->link, ['class' => 'caption']);
             } else {
                 $output[] = $this->image;
                 $caption = new Tag('div', $this->caption, ['class' => 'caption']);
             }
             if (isset($this->description)) {
                 $caption->append_content($this->description);
             }
             if (!empty($this->buttons)) {
                 $button = new Tag('p', implode(PHP_EOL, $this->buttons), ['class' => 'thumbnail-buttons']);
                 $caption->append_content($button);
             }
             $output[] = $caption;
             return (new Tag($this->_tag, implode(PHP_EOL, $output), $this->_attributes))->render();
         }
     }
     return '';
 }

 /**
  * Send using Sendmail.
  *
  * @return bool
  */
 protected function _send_with_sendmail()
 {
     // is popen() enabled?
     if (!function_usable('popen') or false === ($fp = @popen($this->mailpath . ' -oi -f ' . $this->clean_email($this->_headers['From']) . ' -t', 'w'))) {
         // server probably has popen disabled, so nothing we can do to get a verbose error.
         return false;
     }
     fwrite($fp, $this->_header_str);
     fwrite($fp, $this->_finalbody);
     $status = pclose($fp);
     if ($status !== 0) {
         $this->_set_error_message('lang:email_exit_status', $status);
         $this->_set_error_message('lang:email_no_socket');
         return false;
     }
     return true;
 }

 function delete($key)
 {
     $vars =& $GLOBALS['HTTP_SESSION_VARS'];
     if (!function_usable('ini_get') or ini_get('register_globals')) {
         unset($GLOBALS[$key]);
     }
     if (DEBUG) {
         trigger_error("delete session {$key}", E_USER_WARNING);
     }
     unset($vars[$key]);
     session_unregister($key);
 }

 function delete($key)
 {
     if (!function_usable('ini_get') or ini_get('register_globals')) {
         unset($GLOBALS[$key]);
     }
     if (DEBUG) {
         trigger_error("delete session {$key}", E_USER_WARNING);
     }
     unset($_SESSION[$key]);
 }

 /**
  * Send using Sendmail
  *
  * @return	bool
  */
 protected function _send_with_sendmail()
 {
     // is popen() enabled?
     if (!function_usable('popen') or FALSE === ($fp = @popen($this->mailpath . ' -oi -f ' . $this->clean_email($this->_headers['From']) . ' -t', 'w'))) {
         return FALSE;
     }
     fputs($fp, $this->_header_str);
     fputs($fp, $this->_finalbody);
     $status = pclose($fp);
     if ($status !== 0) {
         $this->_set_error_message(_dgettext("system", "Exit status code: %s"), $status);
         $this->_set_error_message(_dgettext("system", "Unable to open a socket to Sendmail. Please check settings."));
         return FALSE;
     }
     return TRUE;
 }

 function delete($key)
 {
     $vars =& $GLOBALS['HTTP_SESSION_VARS'];
     if (!function_usable('ini_get') or ini_get('register_globals')) {
         unset($GLOBALS[$key]);
     }
     if (DEBUG) {
         trigger_error("delete session {$key}", E_USER_WARNING);
     }
     unset($vars[$key]);
     if (isset($_SESSION)) {
         // php-5.2
         unset($_SESSION[$key]);
     }
     if (!check_php_version(5, 3)) {
         session_unregister($key);
     }
 }

 /**
  * File MIME type
  * 文件的MIME类型
  * Detects the (actual) MIME type of the uploaded file, if possible. 检测(实际)上传文件的MIME类型,如果可能的话。
  * The input array is expected to be $_FILES[$field] 输入数组将带有$_FILES($字段)
  *
  * @param	array	$file
  * @return	void
  */
 protected function _file_mime_type($file)
 {
     // We'll need this to validate the MIME info string (e.g. text/plain; charset=us-ascii) 我们需要这个来验证MIME信息字符串(例如文本/平原;charset = us - ascii)
     $regexp = '/^([a-z\\-]+\\/[a-z0-9\\-\\.\\+]+)(;\\s.+)?$/';
     /* Fileinfo extension - most reliable method
      * Fileinfo扩展,最可靠的方法
      * Unfortunately, prior to PHP 5.3 - it's only available as a PECL extension and the
      * more convenient FILEINFO_MIME_TYPE flag doesn't exist.
      * 不幸的是,PHP 5.3之前——这是只有PECL扩展和更方便FILEINFO_MIME_TYPE标识不存在。
      */
     if (function_exists('finfo_file')) {
         $finfo = @finfo_open(FILEINFO_MIME);
         if (is_resource($finfo)) {
             //有可能是一个错误的返回值,如果没有魔法MIME数据库文件系统上发现的
             $mime = @finfo_file($finfo, $file['tmp_name']);
             finfo_close($finfo);
             /* According to the comments section of the PHP manual page, 根据PHP手册页的评论部分,
              * it is possible that this function returns an empty string 有可能是这个函数返回一个空字符串
              * for some files (e.g. if they don't exist in the magic MIME database) 对一些文件(例如,如果他们不存在于魔法MIME数据库)
              */
             if (is_string($mime) && preg_match($regexp, $mime, $matches)) {
                 $this->file_type = $matches[1];
                 return;
             }
         }
     }
     /* This is an ugly hack, but UNIX-type systems provide a "native" way to detect the file type,
      * which is still more secure than depending on the value of $_FILES[$field]['type'], and as it
      * was reported in issue #750 (https://github.com/EllisLab/CodeIgniter/issues/750) - it's better
      * than mime_content_type() as well, hence the attempts to try calling the command line with
      * three different functions.
      * 这是一个丑陋的黑客,但类unix系统提供一种“本地”的方式来检测文件类型,仍比的值取决于安全带有$_file($场)(“类型”),
      * 据报道在问题# 750(https://github.com/EllisLab/CodeIgniter/issues/750)——这比mime_content_type(),
      * 因此,试图尝试调用命令行,有三个不同的功能。
      * Notes: 注释:
      *	- the DIRECTORY_SEPARATOR comparison ensures that we're not on a Windows system       DIRECTORY_SEPARATOR比较确保我们不是在Windows系统上
      *	- many system admins would disable the exec(), shell_exec(), popen() and similar functions 许多系统管理员可以禁用exec(),shell_exec(),popen()和类似的功能
      *	  due to security concerns, hence the function_usable() checks   由于安全问题,因此function_usable()检查
      */
     if (DIRECTORY_SEPARATOR !== '\\') {
         $cmd = function_exists('escapeshellarg') ? 'file --brief --mime ' . escapeshellarg($file['tmp_name']) . ' 2>&1' : 'file --brief --mime ' . $file['tmp_name'] . ' 2>&1';
         if (function_usable('exec')) {
             /* This might look confusing, as $mime is being populated with all of the output when set in the second parameter.
              * 这看起来令人困惑,因为美元mime正在填充所有的输出时,设置在第二个参数。
              * However, we only need the last line, which is the actual return value of exec(), and as such - it overwrites
              * anything that could already be set for $mime previously. This effectively makes the second parameter a dummy
              * value, which is only put to allow us to get the return status code.
              * 然而,我们只需要最后一行,这是实际的exec()的返回值,因此,它覆盖任何可能已经被设置为mime之前。
              * 这有效地使一个假值,第二个参数是只允许我们返回状态代码。
              */
             $mime = @exec($cmd, $mime, $return_status);
             if ($return_status === 0 && is_string($mime) && preg_match($regexp, $mime, $matches)) {
                 $this->file_type = $matches[1];
                 return;
             }
         }
         if (!ini_get('safe_mode') && function_usable('shell_exec')) {
             $mime = @shell_exec($cmd);
             if (strlen($mime) > 0) {
                 $mime = explode("\n", trim($mime));
                 if (preg_match($regexp, $mime[count($mime) - 1], $matches)) {
                     $this->file_type = $matches[1];
                     return;
                 }
             }
         }
         if (function_usable('popen')) {
             $proc = @popen($cmd, 'r');
             if (is_resource($proc)) {
                 $mime = @fread($proc, 512);
                 @pclose($proc);
                 if ($mime !== FALSE) {
                     $mime = explode("\n", trim($mime));
                     if (preg_match($regexp, $mime[count($mime) - 1], $matches)) {
                         $this->file_type = $matches[1];
                         return;
                     }
                 }
             }
         }
     }
     // Fall back to the deprecated mime_content_type(), if available (still better than $_FILES[$field]['type']) 回落到弃用mime_content_type(),如果可用
     if (function_exists('mime_content_type')) {
         $this->file_type = @mime_content_type($file['tmp_name']);
         if (strlen($this->file_type) > 0) {
             return;
         }
     }
     $this->file_type = $file['type'];
 }

 public function _ci_load($_ci_data)
 {
     extract($_ci_data);
     if (isset($_ci_view)) {
         $_ci_path = '';
         /* add file extension if not provided */
         $_ci_file = pathinfo($_ci_view, PATHINFO_EXTENSION) ? $_ci_view : $_ci_view . '.php';
         foreach ($this->_ci_view_paths as $path => $cascade) {
             if (file_exists($view = $path . $_ci_file)) {
                 $_ci_path = $view;
                 break;
             }
             if (!$cascade) {
                 break;
             }
         }
     } elseif (isset($_ci_path)) {
         $_ci_file = basename($_ci_path);
         if (!file_exists($_ci_path)) {
             $_ci_path = '';
         }
     }
     if (empty($_ci_path)) {
         show_error('Unable to load the requested file: ' . $_ci_file);
     }
     if (isset($_ci_vars)) {
         $this->_ci_cached_vars = array_merge($this->_ci_cached_vars, (array) $_ci_vars);
     }
     extract($this->_ci_cached_vars);
     // Added by Ivan Tcholakov, 28-DEC-2013.
     if (!empty($_ci_parsers)) {
         CI::$APP->load->parser();
         $_ci_parsers = CI::$APP->parser->parse_config($_ci_parsers, TRUE);
     } else {
         $_ci_parsers = array();
     }
     //
     ob_start();
     if (empty($_ci_parsers)) {
         if (!is_php('5.4') && !ini_get('short_open_tag') && CI::$APP->config->item('rewrite_short_tags') == TRUE && function_usable('eval')) {
             echo eval('?>' . preg_replace("/;*\\s*\\?>/", "; ?>", str_replace('<?=', '<?php echo ', file_get_contents($_ci_path))));
         } else {
             include $_ci_path;
         }
     } else {
         // This conditional branch has been added by Ivan Tcholakov, 27-DEC-2013.
         if (!isset($_ci_vars)) {
             $_ci_vars = array();
         }
         ob_start();
         if (!is_php('5.4') && !ini_get('short_open_tag') && CI::$APP->config->item('rewrite_short_tags') == TRUE && function_usable('eval')) {
             echo eval('?>' . preg_replace("/;*\\s*\\?>/", "; ?>", str_replace('<?=', '<?php echo ', file_get_contents($_ci_path))));
         } else {
             include $_ci_path;
         }
         $_ci_template_content = ob_get_clean();
         foreach ($_ci_parsers as $_ci_parser) {
             CI::$APP->load->parser($_ci_parser['parser']);
             $_ci_template_content = CI::$APP->{$_ci_parser['parser']}->parse_string($_ci_template_content, $_ci_vars, true, $_ci_parser['config']);
         }
         echo $_ci_template_content;
     }
     log_message('debug', 'File loaded: ' . $_ci_path);
     if ($_ci_return == TRUE) {
         return ob_get_clean();
     }
     if (ob_get_level() > $this->_ci_ob_level + 1) {
         ob_end_flush();
     } else {
         CI::$APP->output->append_output(ob_get_clean());
     }
 }