includes/Revision/RenderedRevision.php

   1 <?php
   2 /**
   3  * This file is part of MediaWiki.
   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  */
  22
  23 namespace MediaWiki\Revision;
  24
  25 use InvalidArgumentException;
  26 use LogicException;
  27 use MediaWiki\Storage\RevisionRecord;
  28 use MediaWiki\Storage\SuppressedDataException;
  29 use ParserOptions;
  30 use ParserOutput;
  31 use Psr\Log\LoggerInterface;
  32 use Psr\Log\NullLogger;
  33 use Revision;
  34 use Title;
  35 use User;
  36 use Wikimedia\Assert\Assert;
  37
  38 /**
  39  * RenderedRevision represents the rendered representation of a revision. It acts as a lazy provider
  40  * of ParserOutput objects for the revision's individual slots, as well as a combined ParserOutput
  41  * of all slots.
  42  *
  43  * @since 1.32
  44  */
  45 class RenderedRevision {
  46
  47         /**
  48          * @var Title
  49          */
  50         private $title;
  51
  52         /** @var RevisionRecord */
  53         private $revision;
  54
  55         /**
  56          * @var ParserOptions
  57          */
  58         private $options;
  59
  60         /**
  61          * @var int Audience to check when accessing content.
  62          */
  63         private $audience = RevisionRecord::FOR_PUBLIC;
  64
  65         /**
  66          * @var User|null The user to use for audience checks during content access.
  67          */
  68         private $forUser = null;
  69
  70         /**
  71          * @var ParserOutput|null The combined ParserOutput for the revision,
  72          *      initialized lazily by getRevisionParserOutput().
  73          */
  74         private $revisionOutput = null;
  75
  76         /**
  77          * @var ParserOutput[] The ParserOutput for each slot,
  78          *      initialized lazily by getSlotParserOutput().
  79          */
  80         private $slotsOutput = [];
  81
  82         /**
  83          * @var callable Callback for combining slot output into revision output.
  84          *      Signature: function ( RenderedRevision $this ): ParserOutput.
  85          */
  86         private $combineOutput;
  87
  88         /**
  89          * @var LoggerInterface For profiling ParserOutput re-use.
  90          */
  91         private $saveParseLogger;
  92
  93         /**
  94          * @note Application logic should not instantiate RenderedRevision instances directly,
  95          * but should use a RevisionRenderer instead.
  96          *
  97          * @param Title $title
  98          * @param RevisionRecord $revision
  99          * @param ParserOptions $options
 100          * @param callable $combineOutput Callback for combining slot output into revision output.
 101          *        Signature: function ( RenderedRevision $this ): ParserOutput.
 102          * @param int $audience Use RevisionRecord::FOR_PUBLIC, FOR_THIS_USER, or RAW.
 103          * @param User|null $forUser Required if $audience is FOR_THIS_USER.
 104          */
 105         public function __construct(
 106                 Title $title,
 107                 RevisionRecord $revision,
 108                 ParserOptions $options,
 109                 callable $combineOutput,
 110                 $audience = RevisionRecord::FOR_PUBLIC,
 111                 User $forUser = null
 112         ) {
 113                 $this->title = $title;
 114                 $this->options = $options;
 115
 116                 $this->setRevisionInternal( $revision );
 117
 118                 $this->combineOutput = $combineOutput;
 119                 $this->saveParseLogger = new NullLogger();
 120
 121                 if ( $audience === RevisionRecord::FOR_THIS_USER && !$forUser ) {
 122                         throw new InvalidArgumentException(
 123                                 'User must be specified when setting audience to FOR_THIS_USER'
 124                         );
 125                 }
 126
 127                 $this->audience = $audience;
 128                 $this->forUser = $forUser;
 129         }
 130
 131         /**
 132          * @param LoggerInterface $saveParseLogger
 133          */
 134         public function setSaveParseLogger( LoggerInterface $saveParseLogger ) {
 135                 $this->saveParseLogger = $saveParseLogger;
 136         }
 137
 138         /**
 139          * @return bool Whether the revision's content has been hidden from unprivileged users.
 140          */
 141         public function isContentDeleted() {
 142                 return $this->revision->isDeleted( RevisionRecord::DELETED_TEXT );
 143         }
 144
 145         /**
 146          * @return RevisionRecord
 147          */
 148         public function getRevision() {
 149                 return $this->revision;
 150         }
 151
 152         /**
 153          * @return ParserOptions
 154          */
 155         public function getOptions() {
 156                 return $this->options;
 157         }
 158
 159         /**
 160          * @return ParserOutput
 161          */
 162         public function getRevisionParserOutput() {
 163                 if ( !$this->revisionOutput ) {
 164                         $output = call_user_func( $this->combineOutput, $this );
 165
 166                         Assert::postcondition(
 167                                 $output instanceof ParserOutput,
 168                                 'Callback did not return a ParserOutput object!'
 169                         );
 170
 171                         $this->revisionOutput = $output;
 172                 }
 173
 174                 return $this->revisionOutput;
 175         }
 176
 177         /**
 178          * @param string $role
 179          *
 180          * @throws SuppressedDataException if the content is not accessible for the audience
 181          *         specified in the constructor.
 182          * @return ParserOutput
 183          */
 184         public function getSlotParserOutput( $role ) {
 185                 // XXX: make html generation optional?
 186
 187                 if ( !isset( $this->slotsOutput[$role] ) ) {
 188                         $content = $this->revision->getContent( $role, $this->audience, $this->forUser );
 189
 190                         if ( !$content ) {
 191                                 throw new SuppressedDataException(
 192                                         'Access to the content has been suppressed for this audience'
 193                                 );
 194                         } else {
 195                                 $this->slotsOutput[ $role ] = $content->getParserOutput(
 196                                         $this->title,
 197                                         $this->revision->getId(),
 198                                         $this->options
 199                                 );
 200
 201                                 // Detach watcher, to ensure option use is not recorded in the wrong ParserOutput.
 202                                 $this->options->registerWatcher( null );
 203                         }
 204                 }
 205
 206                 return $this->slotsOutput[$role];
 207         }
 208
 209         /**
 210          * Updates the RevisionRecord after the revision has been saved. This can be used to discard
 211          * and cached ParserOutput so parser functions like {{REVISIONTIMESTAMP}} or {{REVISIONID}}
 212          * are re-evaluated.
 213          *
 214          * @note There should be no need to call this for null-edits.
 215          *
 216          * @param RevisionRecord $rev
 217          */
 218         public function updateRevision( RevisionRecord $rev ) {
 219                 if ( $rev->getId() === $this->revision->getId() ) {
 220                         return;
 221                 }
 222
 223                 if ( $this->revision->getId() ) {
 224                         throw new LogicException( 'RenderedRevision already has a revision with ID '
 225                                 . $this->revision->getId(), ', can\'t update to revision with ID ' . $rev->getId() );
 226                 }
 227
 228                 if ( !$this->revision->getSlots()->hasSameContent( $rev->getSlots() ) ) {
 229                         throw new LogicException( 'Cannot update to a revision with different content!' );
 230                 }
 231
 232                 $this->setRevisionInternal( $rev );
 233
 234                 $this->pruneRevisionSensitiveOutput( $this->revision->getId() );
 235         }
 236
 237         /**
 238          * Prune any output that depends on the revision ID.
 239          *
 240          * @param int|bool  $actualRevId The actual rev id, to check the used speculative rev ID
 241          *        against, or false to not purge on vary-revision-id, or true to purge on
 242          *        vary-revision-id unconditionally.
 243          */
 244         private function pruneRevisionSensitiveOutput( $actualRevId ) {
 245                 if ( $this->revisionOutput ) {
 246                         if ( $this->outputVariesOnRevisionMetaData( $this->revisionOutput, $actualRevId ) ) {
 247                                 $this->revisionOutput = null;
 248                         }
 249                 } else {
 250                         $this->saveParseLogger->debug( __METHOD__ . ": no prepared revision output...\n" );
 251                 }
 252
 253                 foreach ( $this->slotsOutput as $role => $output ) {
 254                         if ( $this->outputVariesOnRevisionMetaData( $output, $actualRevId ) ) {
 255                                 unset( $this->slotsOutput[$role] );
 256                         }
 257                 }
 258         }
 259
 260         /**
 261          * @param RevisionRecord $revision
 262          */
 263         private function setRevisionInternal( RevisionRecord $revision ) {
 264                 $this->revision = $revision;
 265
 266                 // Make sure the parser uses the correct Revision object
 267                 $title = $this->title;
 268                 $oldCallback = $this->options->getCurrentRevisionCallback();
 269                 $this->options->setCurrentRevisionCallback(
 270                         function ( Title $parserTitle, $parser = false ) use ( $title, $oldCallback ) {
 271                                 if ( $parserTitle->equals( $title ) ) {
 272                                         $legacyRevision = new Revision( $this->revision );
 273                                         return $legacyRevision;
 274                                 } else {
 275                                         return call_user_func( $oldCallback, $parserTitle, $parser );
 276                                 }
 277                         }
 278                 );
 279         }
 280
 281         /**
 282          * @param ParserOutput $out
 283          * @param int|bool  $actualRevId The actual rev id, to check the used speculative rev ID
 284          *        against, or false to not purge on vary-revision-id, or true to purge on
 285          *        vary-revision-id unconditionally.
 286          * @return bool
 287          */
 288         private function outputVariesOnRevisionMetaData( ParserOutput $out, $actualRevId ) {
 289                 $method = __METHOD__;
 290
 291                 if ( $out->getFlag( 'vary-revision' ) ) {
 292                         // XXX: Would be just keep the output if the speculative revision ID was correct,
 293                         // but that can go wrong for some edge cases, like {{PAGEID}} during page creation.
 294                         // For that specific case, it would perhaps nice to have a vary-page flag.
 295                         $this->saveParseLogger->info(
 296                                 "$method: Prepared output has vary-revision...\n"
 297                         );
 298                         return true;
 299                 } elseif ( $out->getFlag( 'vary-revision-id' )
 300                         && $actualRevId !== false
 301                         && ( $actualRevId === true || $out->getSpeculativeRevIdUsed() !== $actualRevId )
 302                 ) {
 303                         $this->saveParseLogger->info(
 304                                 "$method: Prepared output has vary-revision-id with wrong ID...\n"
 305                         );
 306                         return true;
 307                 } else {
 308                         // NOTE: In the original fix for T135261, the output was discarded if 'vary-user' was
 309                         // set for a null-edit. The reason was that the original rendering in that case was
 310                         // targeting the user making the null-edit, not the user who made the original edit,
 311                         // causing {{REVISIONUSER}} to return the wrong name.
 312                         // This case is now expected to be handled by the code in RevisionRenderer that
 313                         // constructs the ParserOptions: For a null-edit, setCurrentRevisionCallback is called
 314                         // with the old, existing revision.
 315
 316                         wfDebug( "$method: Keeping prepared output...\n" );
 317                         return false;
 318                 }
 319         }
 320
 321 }