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 Map of (path => 1) for paths to delete on shutdown */
  35         protected static $pathsCollect = null;
  36
  37         public function __construct( $path ) {
  38                 parent::__construct( $path );
  39
  40                 if ( self::$pathsCollect === null ) {
  41                         self::$pathsCollect = [];
  42                         register_shutdown_function( [ __CLASS__, 'purgeAllOnShutdown' ] );
  43                 }
  44         }
  45
  46         /**
  47          * Make a new temporary file on the file system.
  48          * Temporary files may be purged when the file object falls out of scope.
  49          *
  50          * @param string $prefix
  51          * @param string $extension
  52          * @return TempFSFile|null
  53          */
  54         public static function factory( $prefix, $extension = '' ) {
  55                 $ext = ( $extension != '' ) ? ".{$extension}" : '';
  56
  57                 $attempts = 5;
  58                 while ( $attempts-- ) {
  59                         $path = wfTempDir() . '/' . $prefix . wfRandomString( 12 ) . $ext;
  60                         MediaWiki\suppressWarnings();
  61                         $newFileHandle = fopen( $path, 'x' );
  62                         MediaWiki\restoreWarnings();
  63                         if ( $newFileHandle ) {
  64                                 fclose( $newFileHandle );
  65                                 $tmpFile = new self( $path );
  66                                 $tmpFile->autocollect();
  67                                 // Safely instantiated, end loop.
  68                                 return $tmpFile;
  69                         }
  70                 }
  71
  72                 // Give up
  73                 return null;
  74         }
  75
  76         /**
  77          * Purge this file off the file system
  78          *
  79          * @return bool Success
  80          */
  81         public function purge() {
  82                 $this->canDelete = false; // done
  83                 MediaWiki\suppressWarnings();
  84                 $ok = unlink( $this->path );
  85                 MediaWiki\restoreWarnings();
  86
  87                 unset( self::$pathsCollect[$this->path] );
  88
  89                 return $ok;
  90         }
  91
  92         /**
  93          * Clean up the temporary file only after an object goes out of scope
  94          *
  95          * @param object $object
  96          * @return TempFSFile This object
  97          */
  98         public function bind( $object ) {
  99                 if ( is_object( $object ) ) {
 100                         if ( !isset( $object->tempFSFileReferences ) ) {
 101                                 // Init first since $object might use __get() and return only a copy variable
 102                                 $object->tempFSFileReferences = [];
 103                         }
 104                         $object->tempFSFileReferences[] = $this;
 105                 }
 106
 107                 return $this;
 108         }
 109
 110         /**
 111          * Set flag to not clean up after the temporary file
 112          *
 113          * @return TempFSFile This object
 114          */
 115         public function preserve() {
 116                 $this->canDelete = false;
 117
 118                 unset( self::$pathsCollect[$this->path] );
 119
 120                 return $this;
 121         }
 122
 123         /**
 124          * Set flag clean up after the temporary file
 125          *
 126          * @return TempFSFile This object
 127          */
 128         public function autocollect() {
 129                 $this->canDelete = true;
 130
 131                 self::$pathsCollect[$this->path] = 1;
 132
 133                 return $this;
 134         }
 135
 136         /**
 137          * Try to make sure that all files are purged on error
 138          *
 139          * This method should only be called internally
 140          */
 141         public static function purgeAllOnShutdown() {
 142                 foreach ( self::$pathsCollect as $path ) {
 143                         MediaWiki\suppressWarnings();
 144                         unlink( $path );
 145                         MediaWiki\restoreWarnings();
 146                 }
 147         }
 148
 149         /**
 150          * Cleans up after the temporary file by deleting it
 151          */
 152         function __destruct() {
 153                 if ( $this->canDelete ) {
 154                         $this->purge();
 155                 }
 156         }
 157 }