includes/filebackend/TempFSFile.php

   1 <?php
   2 /**
   3  * Location holder of files stored temporarily
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along
  16  * with this program; if not, write to the Free Software Foundation, Inc.,
  17  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  18  * http://www.gnu.org/copyleft/gpl.html
  19  *
  20  * @file
  21  * @ingroup FileBackend
  22  */
  23
  24 /**
  25  * This class is used to hold the location and do limited manipulation
  26  * of files stored temporarily (this will be whatever wfTempDir() returns)
  27  *
  28  * @ingroup FileBackend
  29  */
  30 class TempFSFile extends FSFile {
  31         /** @var bool Garbage collect the temp file */
  32         protected $canDelete = false;
  33
  34         /** @var array Active temp files to purge on shutdown */
  35         protected static $instances = array();
  36
  37         /** @var array Map of (path => 1) for paths to delete on shutdown */
  38         protected static $pathsCollect = null;
  39
  40         public function __construct( $path ) {
  41                 parent::__construct( $path );
  42
  43                 if ( self::$pathsCollect === null ) {
  44                         self::$pathsCollect = array();
  45                         register_shutdown_function( array( __CLASS__, 'purgeAllOnShutdown' ) );
  46                 }
  47         }
  48
  49         /**
  50          * Make a new temporary file on the file system.
  51          * Temporary files may be purged when the file object falls out of scope.
  52          *
  53          * @param string $prefix
  54          * @param string $extension
  55          * @return TempFSFile|null
  56          */
  57         public static function factory( $prefix, $extension = '' ) {
  58                 $base = wfTempDir() . '/' . $prefix . wfRandomString( 12 );
  59                 $ext = ( $extension != '' ) ? ".{$extension}" : "";
  60                 for ( $attempt = 1; true; $attempt++ ) {
  61                         $path = "{$base}-{$attempt}{$ext}";
  62                         wfSuppressWarnings();
  63                         $newFileHandle = fopen( $path, 'x' );
  64                         wfRestoreWarnings();
  65                         if ( $newFileHandle ) {
  66                                 fclose( $newFileHandle );
  67                                 break; // got it
  68                         }
  69                         if ( $attempt >= 5 ) {
  70
  71                                 return null; // give up
  72                         }
  73                 }
  74                 $tmpFile = new self( $path );
  75                 $tmpFile->autocollect(); // safely instantiated
  76
  77                 return $tmpFile;
  78         }
  79
  80         /**
  81          * Purge this file off the file system
  82          *
  83          * @return bool Success
  84          */
  85         public function purge() {
  86                 $this->canDelete = false; // done
  87                 wfSuppressWarnings();
  88                 $ok = unlink( $this->path );
  89                 wfRestoreWarnings();
  90
  91                 unset( self::$pathsCollect[$this->path] );
  92
  93                 return $ok;
  94         }
  95
  96         /**
  97          * Clean up the temporary file only after an object goes out of scope
  98          *
  99          * @param stdClass $object
 100          * @return TempFSFile This object
 101          */
 102         public function bind( $object ) {
 103                 if ( is_object( $object ) ) {
 104                         if ( !isset( $object->tempFSFileReferences ) ) {
 105                                 // Init first since $object might use __get() and return only a copy variable
 106                                 $object->tempFSFileReferences = array();
 107                         }
 108                         $object->tempFSFileReferences[] = $this;
 109                 }
 110
 111                 return $this;
 112         }
 113
 114         /**
 115          * Set flag to not clean up after the temporary file
 116          *
 117          * @return TempFSFile This object
 118          */
 119         public function preserve() {
 120                 $this->canDelete = false;
 121
 122                 unset( self::$pathsCollect[$this->path] );
 123
 124                 return $this;
 125         }
 126
 127         /**
 128          * Set flag clean up after the temporary file
 129          *
 130          * @return TempFSFile This object
 131          */
 132         public function autocollect() {
 133                 $this->canDelete = true;
 134
 135                 self::$pathsCollect[$this->path] = 1;
 136
 137                 return $this;
 138         }
 139
 140         /**
 141          * Try to make sure that all files are purged on error
 142          *
 143          * This method should only be called internally
 144          */
 145         public static function purgeAllOnShutdown() {
 146                 foreach ( self::$pathsCollect as $path ) {
 147                         wfSuppressWarnings();
 148                         unlink( $path );
 149                         wfRestoreWarnings();
 150                 }
 151         }
 152
 153         /**
 154          * Cleans up after the temporary file by deleting it
 155          */
 156         function __destruct() {
 157                 if ( $this->canDelete ) {
 158                         $this->purge();
 159                 }
 160         }
 161 }