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                         MediaWiki\suppressWarnings();
  63                         $newFileHandle = fopen( $path, 'x' );
  64                         MediaWiki\restoreWarnings();
  65                         if ( $newFileHandle ) {
  66                                 fclose( $newFileHandle );
  67                                 break; // got it
  68                         }
  69                         if ( $attempt >= 5 ) {
  70                                 return null; // give up
  71                         }
  72                 }
  73                 $tmpFile = new self( $path );
  74                 $tmpFile->autocollect(); // safely instantiated
  75
  76                 return $tmpFile;
  77         }
  78
  79         /**
  80          * Purge this file off the file system
  81          *
  82          * @return bool Success
  83          */
  84         public function purge() {
  85                 $this->canDelete = false; // done
  86                 MediaWiki\suppressWarnings();
  87                 $ok = unlink( $this->path );
  88                 MediaWiki\restoreWarnings();
  89
  90                 unset( self::$pathsCollect[$this->path] );
  91
  92                 return $ok;
  93         }
  94
  95         /**
  96          * Clean up the temporary file only after an object goes out of scope
  97          *
  98          * @param object $object
  99          * @return TempFSFile This object
 100          */
 101         public function bind( $object ) {
 102                 if ( is_object( $object ) ) {
 103                         if ( !isset( $object->tempFSFileReferences ) ) {
 104                                 // Init first since $object might use __get() and return only a copy variable
 105                                 $object->tempFSFileReferences = array();
 106                         }
 107                         $object->tempFSFileReferences[] = $this;
 108                 }
 109
 110                 return $this;
 111         }
 112
 113         /**
 114          * Set flag to not clean up after the temporary file
 115          *
 116          * @return TempFSFile This object
 117          */
 118         public function preserve() {
 119                 $this->canDelete = false;
 120
 121                 unset( self::$pathsCollect[$this->path] );
 122
 123                 return $this;
 124         }
 125
 126         /**
 127          * Set flag clean up after the temporary file
 128          *
 129          * @return TempFSFile This object
 130          */
 131         public function autocollect() {
 132                 $this->canDelete = true;
 133
 134                 self::$pathsCollect[$this->path] = 1;
 135
 136                 return $this;
 137         }
 138
 139         /**
 140          * Try to make sure that all files are purged on error
 141          *
 142          * This method should only be called internally
 143          */
 144         public static function purgeAllOnShutdown() {
 145                 foreach ( self::$pathsCollect as $path ) {
 146                         MediaWiki\suppressWarnings();
 147                         unlink( $path );
 148                         MediaWiki\restoreWarnings();
 149                 }
 150         }
 151
 152         /**
 153          * Cleans up after the temporary file by deleting it
 154          */
 155         function __destruct() {
 156                 if ( $this->canDelete ) {
 157                         $this->purge();
 158                 }
 159         }
 160 }