includes/diff/DifferenceInterface.php

   1 <?php
   2 /**
   3  * User interface for the difference engine
   4  *
   5  * @file
   6  * @ingroup DifferenceEngine
   7  */
   8
   9 /**
  10  * Constant to indicate diff cache compatibility.
  11  * Bump this when changing the diff formatting in a way that
  12  * fixes important bugs or such to force cached diff views to
  13  * clear.
  14  */
  15 define( 'MW_DIFF_VERSION', '1.11a' );
  16
  17 /**
  18  * @todo document
  19  * @ingroup DifferenceEngine
  20  */
  21 class DifferenceEngine {
  22         /**#@+
  23          * @private
  24          */
  25         var $mOldid, $mNewid, $mTitle;
  26         var $mOldtitle, $mNewtitle, $mPagetitle;
  27         var $mOldtext, $mNewtext;
  28         var $mOldPage, $mNewPage;
  29         var $mRcidMarkPatrolled;
  30         var $mOldRev, $mNewRev;
  31         var $mRevisionsLoaded = false; // Have the revisions been loaded
  32         var $mTextLoaded = 0; // How many text blobs have been loaded, 0, 1 or 2?
  33         var $mCacheHit = false; // Was the diff fetched from cache?
  34
  35         /**
  36          * Set this to true to add debug info to the HTML output.
  37          * Warning: this may cause RSS readers to spuriously mark articles as "new"
  38          * (bug 20601)
  39          */
  40         var $enableDebugComment = false;
  41
  42         // If true, line X is not displayed when X is 1, for example to increase
  43         // readability and conserve space with many small diffs.
  44         protected $mReducedLineNumbers = false;
  45
  46         protected $unhide = false; # show rev_deleted content if allowed
  47         /**#@-*/
  48
  49         /**
  50          * Constructor
  51          * @param $titleObj Title object that the diff is associated with
  52          * @param $old Integer: old ID we want to show and diff with.
  53          * @param $new String: either 'prev' or 'next'.
  54          * @param $rcid Integer: ??? FIXME (default 0)
  55          * @param $refreshCache boolean If set, refreshes the diff cache
  56          * @param $unhide boolean If set, allow viewing deleted revs
  57          */
  58         function __construct( $titleObj = null, $old = 0, $new = 0, $rcid = 0,
  59                 $refreshCache = false, $unhide = false )
  60         {
  61                 if ( $titleObj ) {
  62                         $this->mTitle = $titleObj;
  63                 } else {
  64                         global $wgTitle;
  65                         $this->mTitle = $wgTitle;
  66                 }
  67                 wfDebug("DifferenceEngine old '$old' new '$new' rcid '$rcid'\n");
  68
  69                 if ( 'prev' === $new ) {
  70                         # Show diff between revision $old and the previous one.
  71                         # Get previous one from DB.
  72                         $this->mNewid = intval($old);
  73                         $this->mOldid = $this->mTitle->getPreviousRevisionID( $this->mNewid );
  74                 } elseif ( 'next' === $new ) {
  75                         # Show diff between revision $old and the next one.
  76                         # Get next one from DB.
  77                         $this->mOldid = intval($old);
  78                         $this->mNewid = $this->mTitle->getNextRevisionID( $this->mOldid );
  79                         if ( false === $this->mNewid ) {
  80                                 # if no result, NewId points to the newest old revision. The only newer
  81                                 # revision is cur, which is "0".
  82                                 $this->mNewid = 0;
  83                         }
  84                 } else {
  85                         $this->mOldid = intval($old);
  86                         $this->mNewid = intval($new);
  87                         wfRunHooks( 'NewDifferenceEngine', array(&$titleObj, &$this->mOldid, &$this->mNewid, $old, $new) );
  88                 }
  89                 $this->mRcidMarkPatrolled = intval($rcid);  # force it to be an integer
  90                 $this->mRefreshCache = $refreshCache;
  91                 $this->unhide = $unhide;
  92         }
  93
  94         function setReducedLineNumbers( $value = true ) {
  95                 $this->mReducedLineNumbers = $value;
  96         }
  97
  98         function getTitle() {
  99                 return $this->mTitle;
 100         }
 101
 102         function wasCacheHit() {
 103                 return $this->mCacheHit;
 104         }
 105
 106         function getOldid() {
 107                 return $this->mOldid;
 108         }
 109
 110         function getNewid() {
 111                 return $this->mNewid;
 112         }
 113
 114         function showDiffPage( $diffOnly = false ) {
 115                 global $wgUser, $wgOut, $wgUseExternalEditor, $wgUseRCPatrol;
 116                 wfProfileIn( __METHOD__ );
 117
 118
 119                 # If external diffs are enabled both globally and for the user,
 120                 # we'll use the application/x-external-editor interface to call
 121                 # an external diff tool like kompare, kdiff3, etc.
 122                 if($wgUseExternalEditor && $wgUser->getOption('externaldiff')) {
 123                         global $wgInputEncoding,$wgServer,$wgScript,$wgLang;
 124                         $wgOut->disable();
 125                         header ( "Content-type: application/x-external-editor; charset=".$wgInputEncoding );
 126                         $url1=$this->mTitle->getFullURL( array(
 127                                 'action' => 'raw',
 128                                 'oldid' => $this->mOldid
 129                         ) );
 130                         $url2=$this->mTitle->getFullURL( array(
 131                                 'action' => 'raw',
 132                                 'oldid' => $this->mNewid
 133                         ) );
 134                         $special=$wgLang->getNsText(NS_SPECIAL);
 135                         $control=<<<CONTROL
 136                         [Process]
 137                         Type=Diff text
 138                         Engine=MediaWiki
 139                         Script={$wgServer}{$wgScript}
 140                         Special namespace={$special}
 141
 142                         [File]
 143                         Extension=wiki
 144                         URL=$url1
 145
 146                         [File 2]
 147                         Extension=wiki
 148                         URL=$url2
 149 CONTROL;
 150                         echo($control);
 151                         return;
 152                 }
 153
 154                 $wgOut->setArticleFlag( false );
 155                 if ( !$this->loadRevisionData() ) {
 156                         $t = $this->mTitle->getPrefixedText();
 157                         $d = wfMsgExt( 'missingarticle-diff', array( 'escape' ), $this->mOldid, $this->mNewid );
 158                         $wgOut->setPagetitle( wfMsg( 'errorpagetitle' ) );
 159                         $wgOut->addWikiMsg( 'missing-article', "<nowiki>$t</nowiki>", $d );
 160                         wfProfileOut( __METHOD__ );
 161                         return;
 162                 }
 163
 164                 wfRunHooks( 'DiffViewHeader', array( $this, $this->mOldRev, $this->mNewRev ) );
 165
 166                 if ( $this->mNewRev->isCurrent() ) {
 167                         $wgOut->setArticleFlag( true );
 168                 }
 169
 170                 # mOldid is false if the difference engine is called with a "vague" query for
 171                 # a diff between a version V and its previous version V' AND the version V
 172                 # is the first version of that article. In that case, V' does not exist.
 173                 if ( $this->mOldid === false ) {
 174                         $this->showFirstRevision();
 175                         $this->renderNewRevision();  // should we respect $diffOnly here or not?
 176                         wfProfileOut( __METHOD__ );
 177                         return;
 178                 }
 179
 180                 $wgOut->suppressQuickbar();
 181
 182                 $oldTitle = $this->mOldPage->getPrefixedText();
 183                 $newTitle = $this->mNewPage->getPrefixedText();
 184                 if( $oldTitle == $newTitle ) {
 185                         $wgOut->setPageTitle( $newTitle );
 186                 } else {
 187                         $wgOut->setPageTitle( $oldTitle . ', ' . $newTitle );
 188                 }
 189                 if ( $this->mNewPage->equals( $this->mOldPage ) ) {
 190                         $wgOut->setSubtitle( wfMsgExt( 'difference', array( 'parseinline' ) ) );
 191                 } else {
 192                         $wgOut->setSubtitle( wfMsgExt( 'difference-multipage', array( 'parseinline' ) ) );
 193                 }
 194                 $wgOut->setRobotPolicy( 'noindex,nofollow' );
 195
 196                 if ( !$this->mOldPage->userCanRead() || !$this->mNewPage->userCanRead() ) {
 197                         $wgOut->loginToUse();
 198                         $wgOut->output();
 199                         $wgOut->disable();
 200                         wfProfileOut( __METHOD__ );
 201                         return;
 202                 }
 203
 204                 $sk = $wgUser->getSkin();
 205
 206                 // Check if page is editable
 207                 $editable = $this->mNewRev->getTitle()->userCan( 'edit' );
 208                 if ( $editable && $this->mNewRev->isCurrent() && $wgUser->isAllowed( 'rollback' ) ) {
 209                         $rollback = '&#160;&#160;&#160;' . $sk->generateRollback( $this->mNewRev );
 210                 } else {
 211                         $rollback = '';
 212                 }
 213
 214                 // Prepare a change patrol link, if applicable
 215                 if( $wgUseRCPatrol && $this->mTitle->userCan('patrol') ) {
 216                         // If we've been given an explicit change identifier, use it; saves time
 217                         if( $this->mRcidMarkPatrolled ) {
 218                                 $rcid = $this->mRcidMarkPatrolled;
 219                                 $rc = RecentChange::newFromId( $rcid );
 220                                 // Already patrolled?
 221                                 $rcid = is_object($rc) && !$rc->getAttribute('rc_patrolled') ? $rcid : 0;
 222                         } else {
 223                                 // Look for an unpatrolled change corresponding to this diff
 224                                 $db = wfGetDB( DB_SLAVE );
 225                                 $change = RecentChange::newFromConds(
 226                                         array(
 227                                         // Redundant user,timestamp condition so we can use the existing index
 228                                                 'rc_user_text'  => $this->mNewRev->getRawUserText(),
 229                                                 'rc_timestamp'  => $db->timestamp( $this->mNewRev->getTimestamp() ),
 230                                                 'rc_this_oldid' => $this->mNewid,
 231                                                 'rc_last_oldid' => $this->mOldid,
 232                                                 'rc_patrolled'  => 0
 233                                         ),
 234                                         __METHOD__
 235                                 );
 236                                 if( $change instanceof RecentChange ) {
 237                                         $rcid = $change->mAttribs['rc_id'];
 238                                         $this->mRcidMarkPatrolled = $rcid;
 239                                 } else {
 240                                         // None found
 241                                         $rcid = 0;
 242                                 }
 243                         }
 244                         // Build the link
 245                         if( $rcid ) {
 246                                 $token = $wgUser->editToken();
 247                                 $patrol = ' <span class="patrollink">[' . $sk->link(
 248                                         $this->mTitle,
 249                                         wfMsgHtml( 'markaspatrolleddiff' ),
 250                                         array(),
 251                                         array(
 252                                                 'action' => 'markpatrolled',
 253                                                 'rcid' => $rcid,
 254                                                 'token' => $token,
 255                                         ),
 256                                         array(
 257                                                 'known',
 258                                                 'noclasses'
 259                                         )
 260                                 ) . ']</span>';
 261                         } else {
 262                                 $patrol = '';
 263                         }
 264                 } else {
 265                         $patrol = '';
 266                 }
 267
 268                 # Carry over 'diffonly' param via navigation links
 269                 if( $diffOnly != $wgUser->getBoolOption('diffonly') ) {
 270                         $query['diffonly'] = $diffOnly;
 271                 }
 272
 273                 # Make "previous revision link"
 274                 $query['diff'] = 'prev';
 275                 $query['oldid'] = $this->mOldid;
 276                 # Cascade unhide param in links for easy deletion browsing
 277                 if( $this->unhide ) {
 278                         $query['unhide'] = 1;
 279                 }
 280                 if( !$this->mOldRev->getPrevious() ) {
 281                         $prevlink = '&#160;';
 282                 } else {
 283                         $prevlink = $sk->link(
 284                                 $this->mTitle,
 285                                 wfMsgHtml( 'previousdiff' ),
 286                                 array(
 287                                         'id' => 'differences-prevlink'
 288                                 ),
 289                                 $query,
 290                                 array(
 291                                         'known',
 292                                         'noclasses'
 293                                 )
 294                         );
 295                 }
 296
 297                 # Make "next revision link"
 298                 $query['diff'] = 'next';
 299                 $query['oldid'] = $this->mNewid;
 300                 # Skip next link on the top revision
 301                 if( $this->mNewRev->isCurrent() ) {
 302                         $nextlink = '&#160;';
 303                 } else {
 304                         $nextlink = $sk->link(
 305                                 $this->mTitle,
 306                                 wfMsgHtml( 'nextdiff' ),
 307                                 array(
 308                                         'id' => 'differences-nextlink'
 309                                 ),
 310                                 $query,
 311                                 array(
 312                                         'known',
 313                                         'noclasses'
 314                                 )
 315                         );
 316                 }
 317
 318                 $oldminor = '';
 319                 $newminor = '';
 320
 321                 if( $this->mOldRev->isMinor() ) {
 322                         $oldminor = ChangesList::flag( 'minor' );
 323                 }
 324                 if( $this->mNewRev->isMinor() ) {
 325                         $newminor = ChangesList::flag( 'minor' );
 326                 }
 327
 328                 # Handle RevisionDelete links...
 329                 $ldel = $this->revisionDeleteLink( $this->mOldRev );
 330                 $rdel = $this->revisionDeleteLink( $this->mNewRev );
 331
 332                 $oldHeader = '<div id="mw-diff-otitle1"><strong>'.$this->mOldtitle.'</strong></div>' .
 333                         '<div id="mw-diff-otitle2">' .
 334                                 $sk->revUserTools( $this->mOldRev, !$this->unhide ).'</div>' .
 335                         '<div id="mw-diff-otitle3">' . $oldminor .
 336                                 $sk->revComment( $this->mOldRev, !$diffOnly, !$this->unhide ).$ldel.'</div>' .
 337                         '<div id="mw-diff-otitle4">' . $prevlink .'</div>';
 338                 $newHeader = '<div id="mw-diff-ntitle1"><strong>'.$this->mNewtitle.'</strong></div>' .
 339                         '<div id="mw-diff-ntitle2">' . $sk->revUserTools( $this->mNewRev, !$this->unhide ) .
 340                                 " $rollback</div>" .
 341                         '<div id="mw-diff-ntitle3">' . $newminor .
 342                                 $sk->revComment( $this->mNewRev, !$diffOnly, !$this->unhide ).$rdel.'</div>' .
 343                         '<div id="mw-diff-ntitle4">' . $nextlink . $patrol . '</div>';
 344
 345                 # Check if this user can see the revisions
 346                 $allowed = $this->mOldRev->userCan(Revision::DELETED_TEXT)
 347                         && $this->mNewRev->userCan(Revision::DELETED_TEXT);
 348                 # Check if one of the revisions is deleted/suppressed
 349                 $deleted = $suppressed = false;
 350                 if( $this->mOldRev->isDeleted(Revision::DELETED_TEXT) ) {
 351                         $deleted = true; // old revisions text is hidden
 352                         if( $this->mOldRev->isDeleted(Revision::DELETED_RESTRICTED) )
 353                                 $suppressed = true; // also suppressed
 354                 }
 355                 if( $this->mNewRev->isDeleted(Revision::DELETED_TEXT) ) {
 356                         $deleted = true; // new revisions text is hidden
 357                         if( $this->mNewRev->isDeleted(Revision::DELETED_RESTRICTED) )
 358                                 $suppressed = true; // also suppressed
 359                 }
 360                 # If the diff cannot be shown due to a deleted revision, then output
 361                 # the diff header and links to unhide (if available)...
 362                 if( $deleted && (!$this->unhide || !$allowed) ) {
 363                         $this->showDiffStyle();
 364                         $multi = $this->getMultiNotice();
 365                         $wgOut->addHTML( $this->addHeader( '', $oldHeader, $newHeader, $multi ) );
 366                         if( !$allowed ) {
 367                                 $msg = $suppressed ? 'rev-suppressed-no-diff' : 'rev-deleted-no-diff';
 368                                 # Give explanation for why revision is not visible
 369                                 $wgOut->wrapWikiMsg( "<div class='mw-warning plainlinks'>\n$1\n</div>\n",
 370                                         array( $msg ) );
 371                         } else {
 372                                 # Give explanation and add a link to view the diff...
 373                                 $link = $this->mTitle->getFullUrl( array(
 374                                         'diff' => $this->mNewid,
 375                                         'oldid' => $this->mOldid,
 376                                         'unhide' => 1
 377                                 ) );
 378                                 $msg = $suppressed ? 'rev-suppressed-unhide-diff' : 'rev-deleted-unhide-diff';
 379                                 $wgOut->wrapWikiMsg( "<div class='mw-warning plainlinks'>\n$1\n</div>\n", array( $msg, $link ) );
 380                         }
 381                 # Otherwise, output a regular diff...
 382                 } else {
 383                         # Add deletion notice if the user is viewing deleted content
 384                         $notice = '';
 385                         if( $deleted ) {
 386                                 $msg = $suppressed ? 'rev-suppressed-diff-view' : 'rev-deleted-diff-view';
 387                                 $notice = "<div class='mw-warning plainlinks'>\n".wfMsgExt($msg,'parseinline')."</div>\n";
 388                         }
 389                         $this->showDiff( $oldHeader, $newHeader, $notice );
 390                         if( !$diffOnly ) {
 391                                 $this->renderNewRevision();
 392                         }
 393                 }
 394                 wfProfileOut( __METHOD__ );
 395         }
 396
 397         protected function revisionDeleteLink( $rev ) {
 398                 global $wgUser;
 399                 $link = '';
 400                 $canHide = $wgUser->isAllowed( 'deleterevision' );
 401                 // Show del/undel link if:
 402                 // (a) the user can delete revisions, or
 403                 // (b) the user can view deleted revision *and* this one is deleted
 404                 if( $canHide || ($rev->getVisibility() && $wgUser->isAllowed( 'deletedhistory' )) ) {
 405                         $sk = $wgUser->getSkin();
 406                         if( !$rev->userCan( Revision::DELETED_RESTRICTED ) ) {
 407                                 $link = $sk->revDeleteLinkDisabled( $canHide ); // revision was hidden from sysops
 408                         } else {
 409                                 $query = array(
 410                                         'type'   => 'revision',
 411                                         'target' => $rev->mTitle->getPrefixedDbkey(),
 412                                         'ids'    => $rev->getId()
 413                                 );
 414                                 $link = $sk->revDeleteLink( $query,
 415                                         $rev->isDeleted( Revision::DELETED_RESTRICTED ), $canHide );
 416                         }
 417                         $link = '&#160;&#160;&#160;' . $link . ' ';
 418                 }
 419                 return $link;
 420         }
 421
 422         /**
 423          * Show the new revision of the page.
 424          */
 425         function renderNewRevision() {
 426                 global $wgOut, $wgUser;
 427                 wfProfileIn( __METHOD__ );
 428
 429                 $wgOut->addHTML( "<hr /><h2>{$this->mPagetitle}</h2>\n" );
 430                 # Add deleted rev tag if needed
 431                 if( !$this->mNewRev->userCan(Revision::DELETED_TEXT) ) {
 432                         $wgOut->wrapWikiMsg( "<div class='mw-warning plainlinks'>\n$1\n</div>\n", 'rev-deleted-text-permission' );
 433                 } else if( $this->mNewRev->isDeleted(Revision::DELETED_TEXT) ) {
 434                         $wgOut->wrapWikiMsg( "<div class='mw-warning plainlinks'>\n$1\n</div>\n", 'rev-deleted-text-view' );
 435                 }
 436
 437                 $pCache = true;
 438                 if( !$this->mNewRev->isCurrent() ) {
 439                         $oldEditSectionSetting = $wgOut->parserOptions()->setEditSection( false );
 440                         $pCache = false;
 441                 }
 442
 443                 $this->loadNewText();
 444                 if( is_object( $this->mNewRev ) ) {
 445                         $wgOut->setRevisionId( $this->mNewRev->getId() );
 446                 }
 447
 448                 if( $this->mTitle->isCssJsSubpage() || $this->mTitle->isCssOrJsPage() ) {
 449                         // Stolen from Article::view --AG 2007-10-11
 450                         // Give hooks a chance to customise the output
 451                         if( wfRunHooks( 'ShowRawCssJs', array( $this->mNewtext, $this->mTitle, $wgOut ) ) ) {
 452                                 // Wrap the whole lot in a <pre> and don't parse
 453                                 $m = array();
 454                                 preg_match( '!\.(css|js)$!u', $this->mTitle->getText(), $m );
 455                                 $wgOut->addHTML( "<pre class=\"mw-code mw-{$m[1]}\" dir=\"ltr\">\n" );
 456                                 $wgOut->addHTML( htmlspecialchars( $this->mNewtext ) );
 457                                 $wgOut->addHTML( "\n</pre>\n" );
 458                         }
 459                 } elseif( $pCache ) {
 460                         $article = new Article( $this->mTitle, 0 );
 461                         $pOutput = ParserCache::singleton()->get( $article, $wgOut->parserOptions() );
 462                         if( $pOutput ) {
 463                                 $wgOut->addParserOutput( $pOutput );
 464                         } else {
 465                                 $article->doViewParse();
 466                         }
 467                 } else {
 468                         $wgOut->addWikiTextTidy( $this->mNewtext );
 469                 }
 470
 471                 if( is_object( $this->mNewRev ) && !$this->mNewRev->isCurrent() ) {
 472                         $wgOut->parserOptions()->setEditSection( $oldEditSectionSetting );
 473                 }
 474                 # Add redundant patrol link on bottom...
 475                 if( $this->mRcidMarkPatrolled && $this->mTitle->quickUserCan('patrol') ) {
 476                         $sk = $wgUser->getSkin();
 477                         $token = $wgUser->editToken();
 478                         $wgOut->addHTML(
 479                                 "<div class='patrollink'>[" . $sk->link(
 480                                         $this->mTitle,
 481                                         wfMsgHtml( 'markaspatrolleddiff' ),
 482                                         array(),
 483                                         array(
 484                                                 'action' => 'markpatrolled',
 485                                                 'rcid' => $this->mRcidMarkPatrolled,
 486                                                 'token' => $token,
 487                                         )
 488                                 ) . ']</div>'
 489                          );
 490                 }
 491
 492                 wfProfileOut( __METHOD__ );
 493         }
 494
 495         /**
 496          * Show the first revision of an article. Uses normal diff headers in
 497          * contrast to normal "old revision" display style.
 498          */
 499         function showFirstRevision() {
 500                 global $wgOut, $wgUser;
 501                 wfProfileIn( __METHOD__ );
 502
 503                 # Get article text from the DB
 504                 #
 505                 if ( ! $this->loadNewText() ) {
 506                         $t = $this->mTitle->getPrefixedText();
 507                         $d = wfMsgExt( 'missingarticle-diff', array( 'escape' ), $this->mOldid, $this->mNewid );
 508                         $wgOut->setPagetitle( wfMsg( 'errorpagetitle' ) );
 509                         $wgOut->addWikiMsg( 'missing-article', "<nowiki>$t</nowiki>", $d );
 510                         wfProfileOut( __METHOD__ );
 511                         return;
 512                 }
 513                 if ( $this->mNewRev->isCurrent() ) {
 514                         $wgOut->setArticleFlag( true );
 515                 }
 516
 517                 # Check if user is allowed to look at this page. If not, bail out.
 518                 #
 519                 if ( !$this->mTitle->userCanRead() ) {
 520                         $wgOut->loginToUse();
 521                         $wgOut->output();
 522                         wfProfileOut( __METHOD__ );
 523                         throw new MWException("Permission Error: you do not have access to view this page");
 524                 }
 525
 526                 # Prepare the header box
 527                 #
 528                 $sk = $wgUser->getSkin();
 529
 530                 $next = $this->mTitle->getNextRevisionID( $this->mNewid );
 531                 if( !$next ) {
 532                         $nextlink = '';
 533                 } else {
 534                         $nextlink = '<br />' . $sk->link(
 535                                 $this->mTitle,
 536                                 wfMsgHtml( 'nextdiff' ),
 537                                 array(
 538                                         'id' => 'differences-nextlink'
 539                                 ),
 540                                 array(
 541                                         'diff' => 'next',
 542                                         'oldid' => $this->mNewid,
 543                                 ),
 544                                 array(
 545                                         'known',
 546                                         'noclasses'
 547                                 )
 548                         );
 549                 }
 550                 $header = "<div class=\"firstrevisionheader\" style=\"text-align: center\">" .
 551                         $sk->revUserTools( $this->mNewRev ) . "<br />" . $sk->revComment( $this->mNewRev ) . $nextlink . "</div>\n";
 552
 553                 $wgOut->addHTML( $header );
 554
 555                 $wgOut->setSubtitle( wfMsgExt( 'difference', array( 'parseinline' ) ) );
 556                 $wgOut->setRobotPolicy( 'noindex,nofollow' );
 557
 558                 wfProfileOut( __METHOD__ );
 559         }
 560
 561         /**
 562          * Get the diff text, send it to $wgOut
 563          * Returns false if the diff could not be generated, otherwise returns true
 564          */
 565         function showDiff( $otitle, $ntitle, $notice = '' ) {
 566                 global $wgOut;
 567                 $diff = $this->getDiff( $otitle, $ntitle, $notice );
 568                 if ( $diff === false ) {
 569                         $wgOut->addWikiMsg( 'missing-article', "<nowiki>(fixme, bug)</nowiki>", '' );
 570                         return false;
 571                 } else {
 572                         $this->showDiffStyle();
 573                         $wgOut->addHTML( $diff );
 574                         return true;
 575                 }
 576         }
 577
 578         /**
 579          * Add style sheets and supporting JS for diff display.
 580          */
 581         function showDiffStyle() {
 582                 global $wgStylePath, $wgStyleVersion, $wgOut;
 583                 $wgOut->addModules( 'mediawiki.legacy.diff' );
 584         }
 585
 586         /**
 587          * Get complete diff table, including header
 588          *
 589          * @param $otitle Title: old title
 590          * @param $ntitle Title: new title
 591          * @param $notice String: HTML between diff header and body
 592          * @return mixed
 593          */
 594         function getDiff( $otitle, $ntitle, $notice = '' ) {
 595                 $body = $this->getDiffBody();
 596                 if ( $body === false ) {
 597                         return false;
 598                 } else {
 599                         $multi = $this->getMultiNotice();
 600                         return $this->addHeader( $body, $otitle, $ntitle, $multi, $notice );
 601                 }
 602         }
 603
 604         /**
 605          * Get the diff table body, without header
 606          *
 607          * @return mixed
 608          */
 609         function getDiffBody() {
 610                 global $wgMemc;
 611                 wfProfileIn( __METHOD__ );
 612                 $this->mCacheHit = true;
 613                 // Check if the diff should be hidden from this user
 614                 if ( !$this->loadRevisionData() )
 615                         return '';
 616                 if ( $this->mOldRev && !$this->mOldRev->userCan(Revision::DELETED_TEXT) ) {
 617                         return '';
 618                 } else if ( $this->mNewRev && !$this->mNewRev->userCan(Revision::DELETED_TEXT) ) {
 619                         return '';
 620                 } else if ( $this->mOldRev && $this->mNewRev && $this->mOldRev->getID() == $this->mNewRev->getID() ) {
 621                         return '';
 622                 }
 623                 // Cacheable?
 624                 $key = false;
 625                 if ( $this->mOldid && $this->mNewid ) {
 626                         $key = wfMemcKey( 'diff', 'version', MW_DIFF_VERSION, 'oldid', $this->mOldid, 'newid', $this->mNewid );
 627                         // Try cache
 628                         if ( !$this->mRefreshCache ) {
 629                                 $difftext = $wgMemc->get( $key );
 630                                 if ( $difftext ) {
 631                                         wfIncrStats( 'diff_cache_hit' );
 632                                         $difftext = $this->localiseLineNumbers( $difftext );
 633                                         $difftext .= "\n<!-- diff cache key $key -->\n";
 634                                         wfProfileOut( __METHOD__ );
 635                                         return $difftext;
 636                                 }
 637                         } // don't try to load but save the result
 638                 }
 639                 $this->mCacheHit = false;
 640
 641                 // Loadtext is permission safe, this just clears out the diff
 642                 if ( !$this->loadText() ) {
 643                         wfProfileOut( __METHOD__ );
 644                         return false;
 645                 }
 646
 647                 $difftext = $this->generateDiffBody( $this->mOldtext, $this->mNewtext );
 648
 649                 // Save to cache for 7 days
 650                 if ( !wfRunHooks( 'AbortDiffCache', array( &$this ) ) ) {
 651                         wfIncrStats( 'diff_uncacheable' );
 652                 } else if ( $key !== false && $difftext !== false ) {
 653                         wfIncrStats( 'diff_cache_miss' );
 654                         $wgMemc->set( $key, $difftext, 7*86400 );
 655                 } else {
 656                         wfIncrStats( 'diff_uncacheable' );
 657                 }
 658                 // Replace line numbers with the text in the user's language
 659                 if ( $difftext !== false ) {
 660                         $difftext = $this->localiseLineNumbers( $difftext );
 661                 }
 662                 wfProfileOut( __METHOD__ );
 663                 return $difftext;
 664         }
 665
 666         /**
 667          * Make sure the proper modules are loaded before we try to
 668          * make the diff
 669          */
 670         private function initDiffEngines() {
 671                 global $wgExternalDiffEngine;
 672                 if ( $wgExternalDiffEngine == 'wikidiff' && !function_exists( 'wikidiff_do_diff' ) ) {
 673                         wfProfileIn( __METHOD__ . '-php_wikidiff.so' );
 674                         wfSuppressWarnings();
 675                         dl( 'php_wikidiff.so' );
 676                         wfRestoreWarnings();
 677                         wfProfileOut( __METHOD__ . '-php_wikidiff.so' );
 678                 }
 679                 else if ( $wgExternalDiffEngine == 'wikidiff2' && !function_exists( 'wikidiff2_do_diff' ) ) {
 680                         wfProfileIn( __METHOD__ . '-php_wikidiff2.so' );
 681                         wfSuppressWarnings();
 682                         wfDl( 'wikidiff2' );
 683                         wfRestoreWarnings();
 684                         wfProfileOut( __METHOD__ . '-php_wikidiff2.so' );
 685                 }
 686         }
 687
 688         /**
 689          * Generate a diff, no caching
 690          *
 691          * @param $otext String: old text, must be already segmented
 692          * @param $ntext String: new text, must be already segmented
 693          */
 694         function generateDiffBody( $otext, $ntext ) {
 695                 global $wgExternalDiffEngine, $wgContLang;
 696
 697                 $otext = str_replace( "\r\n", "\n", $otext );
 698                 $ntext = str_replace( "\r\n", "\n", $ntext );
 699
 700                 $this->initDiffEngines();
 701
 702                 if ( $wgExternalDiffEngine == 'wikidiff' && function_exists( 'wikidiff_do_diff' ) ) {
 703                         # For historical reasons, external diff engine expects
 704                         # input text to be HTML-escaped already
 705                         $otext = htmlspecialchars ( $wgContLang->segmentForDiff( $otext ) );
 706                         $ntext = htmlspecialchars ( $wgContLang->segmentForDiff( $ntext ) );
 707                         return $wgContLang->unsegementForDiff( wikidiff_do_diff( $otext, $ntext, 2 ) ) .
 708                         $this->debug( 'wikidiff1' );
 709                 }
 710
 711                 if ( $wgExternalDiffEngine == 'wikidiff2' && function_exists( 'wikidiff2_do_diff' ) ) {
 712                         # Better external diff engine, the 2 may some day be dropped
 713                         # This one does the escaping and segmenting itself
 714                         wfProfileIn( 'wikidiff2_do_diff' );
 715                         $text = wikidiff2_do_diff( $otext, $ntext, 2 );
 716                         $text .= $this->debug( 'wikidiff2' );
 717                         wfProfileOut( 'wikidiff2_do_diff' );
 718                         return $text;
 719                 }
 720                 if ( $wgExternalDiffEngine != 'wikidiff3' && $wgExternalDiffEngine !== false ) {
 721                         # Diff via the shell
 722                         global $wgTmpDirectory;
 723                         $tempName1 = tempnam( $wgTmpDirectory, 'diff_' );
 724                         $tempName2 = tempnam( $wgTmpDirectory, 'diff_' );
 725
 726                         $tempFile1 = fopen( $tempName1, "w" );
 727                         if ( !$tempFile1 ) {
 728                                 wfProfileOut( __METHOD__ );
 729                                 return false;
 730                         }
 731                         $tempFile2 = fopen( $tempName2, "w" );
 732                         if ( !$tempFile2 ) {
 733                                 wfProfileOut( __METHOD__ );
 734                                 return false;
 735                         }
 736                         fwrite( $tempFile1, $otext );
 737                         fwrite( $tempFile2, $ntext );
 738                         fclose( $tempFile1 );
 739                         fclose( $tempFile2 );
 740                         $cmd = wfEscapeShellArg( $wgExternalDiffEngine, $tempName1, $tempName2 );
 741                         wfProfileIn( __METHOD__ . "-shellexec" );
 742                         $difftext = wfShellExec( $cmd );
 743                         $difftext .= $this->debug( "external $wgExternalDiffEngine" );
 744                         wfProfileOut( __METHOD__ . "-shellexec" );
 745                         unlink( $tempName1 );
 746                         unlink( $tempName2 );
 747                         return $difftext;
 748                 }
 749
 750                 # Native PHP diff
 751                 $ota = explode( "\n", $wgContLang->segmentForDiff( $otext ) );
 752                 $nta = explode( "\n", $wgContLang->segmentForDiff( $ntext ) );
 753                 $diffs = new Diff( $ota, $nta );
 754                 $formatter = new TableDiffFormatter();
 755                 return $wgContLang->unsegmentForDiff( $formatter->format( $diffs ) ) .
 756                 $this->debug();
 757         }
 758
 759         /**
 760          * Generate a debug comment indicating diff generating time,
 761          * server node, and generator backend.
 762          */
 763         protected function debug( $generator="internal" ) {
 764                 global $wgShowHostnames;
 765                 if ( !$this->enableDebugComment ) {
 766                         return '';
 767                 }
 768                 $data = array( $generator );
 769                 if( $wgShowHostnames ) {
 770                         $data[] = wfHostname();
 771                 }
 772                 $data[] = wfTimestamp( TS_DB );
 773                 return "<!-- diff generator: " .
 774                 implode( " ",
 775                 array_map(
 776                                         "htmlspecialchars",
 777                 $data ) ) .
 778                         " -->\n";
 779         }
 780
 781         /**
 782          * Replace line numbers with the text in the user's language
 783          */
 784         function localiseLineNumbers( $text ) {
 785                 return preg_replace_callback( '/<!--LINE (\d+)-->/',
 786                 array( &$this, 'localiseLineNumbersCb' ), $text );
 787         }
 788
 789         function localiseLineNumbersCb( $matches ) {
 790                 global $wgLang;
 791                 if ( $matches[1] === '1' && $this->mReducedLineNumbers ) return '';
 792                 return wfMsgExt( 'lineno', 'escape', $wgLang->formatNum( $matches[1] ) );
 793         }
 794
 795
 796         /**
 797          * If there are revisions between the ones being compared, return a note saying so.
 798          */
 799         function getMultiNotice() {
 800                 if ( !is_object($this->mOldRev) || !is_object($this->mNewRev) )
 801                 return '';
 802
 803                 if( !$this->mOldPage->equals( $this->mNewPage ) ) {
 804                         // Comparing two different pages? Count would be meaningless.
 805                         return '';
 806                 }
 807
 808                 $oldid = $this->mOldRev->getId();
 809                 $newid = $this->mNewRev->getId();
 810                 if ( $oldid > $newid ) {
 811                         $tmp = $oldid; $oldid = $newid; $newid = $tmp;
 812                 }
 813
 814                 $n = $this->mTitle->countRevisionsBetween( $oldid, $newid );
 815                 if ( !$n )
 816                 return '';
 817
 818                 return wfMsgExt( 'diff-multi', array( 'parseinline' ), $n );
 819         }
 820
 821
 822         /**
 823          * Add the header to a diff body
 824          */
 825         static function addHeader( $diff, $otitle, $ntitle, $multi = '', $notice = '' ) {
 826                 $header = "<table class='diff'>";
 827                 if( $diff ) { // Safari/Chrome show broken output if cols not used
 828                         $header .= "
 829                         <col class='diff-marker' />
 830                         <col class='diff-content' />
 831                         <col class='diff-marker' />
 832                         <col class='diff-content' />";
 833                         $colspan = 2;
 834                         $multiColspan = 4;
 835                 } else {
 836                         $colspan = 1;
 837                         $multiColspan = 2;
 838                 }
 839                 $header .= "
 840                 <tr valign='top'>
 841                 <td colspan='$colspan' class='diff-otitle'>{$otitle}</td>
 842                 <td colspan='$colspan' class='diff-ntitle'>{$ntitle}</td>
 843                 </tr>";
 844
 845                 if ( $multi != '' ) {
 846                         $header .= "<tr><td colspan='{$multiColspan}' align='center' class='diff-multi'>{$multi}</td></tr>";
 847                 }
 848                 if ( $notice != '' ) {
 849                         $header .= "<tr><td colspan='{$multiColspan}' align='center'>{$notice}</td></tr>";
 850                 }
 851
 852                 return $header . $diff . "</table>";
 853         }
 854
 855         /**
 856          * Use specified text instead of loading from the database
 857          */
 858         function setText( $oldText, $newText ) {
 859                 $this->mOldtext = $oldText;
 860                 $this->mNewtext = $newText;
 861                 $this->mTextLoaded = 2;
 862                 $this->mRevisionsLoaded = true;
 863         }
 864
 865         /**
 866          * Load revision metadata for the specified articles. If newid is 0, then compare
 867          * the old article in oldid to the current article; if oldid is 0, then
 868          * compare the current article to the immediately previous one (ignoring the
 869          * value of newid).
 870          *
 871          * If oldid is false, leave the corresponding revision object set
 872          * to false. This is impossible via ordinary user input, and is provided for
 873          * API convenience.
 874          */
 875         function loadRevisionData() {
 876                 global $wgLang, $wgUser;
 877                 if ( $this->mRevisionsLoaded ) {
 878                         return true;
 879                 } else {
 880                         // Whether it succeeds or fails, we don't want to try again
 881                         $this->mRevisionsLoaded = true;
 882                 }
 883
 884                 // Load the new revision object
 885                 $this->mNewRev = $this->mNewid
 886                         ? Revision::newFromId( $this->mNewid )
 887                         : Revision::newFromTitle( $this->mTitle );
 888                 if( !$this->mNewRev instanceof Revision )
 889                         return false;
 890
 891                 // Update the new revision ID in case it was 0 (makes life easier doing UI stuff)
 892                 $this->mNewid = $this->mNewRev->getId();
 893
 894                 // Check if page is editable
 895                 $editable = $this->mNewRev->getTitle()->userCan( 'edit' );
 896
 897                 // Set assorted variables
 898                 $timestamp = $wgLang->timeanddate( $this->mNewRev->getTimestamp(), true );
 899                 $dateofrev = $wgLang->date( $this->mNewRev->getTimestamp(), true );
 900                 $timeofrev = $wgLang->time( $this->mNewRev->getTimestamp(), true );
 901                 $this->mNewPage = $this->mNewRev->getTitle();
 902                 if( $this->mNewRev->isCurrent() ) {
 903                         $newLink = $this->mNewPage->escapeLocalUrl( array(
 904                                 'oldid' => $this->mNewid
 905                         ) );
 906                         $this->mPagetitle = htmlspecialchars( wfMsg(
 907                                 'currentrev-asof',
 908                                 $timestamp,
 909                                 $dateofrev,
 910                                 $timeofrev
 911                         ) );
 912                         $newEdit = $this->mNewPage->escapeLocalUrl( array(
 913                                 'action' => 'edit'
 914                         ) );
 915
 916                         $this->mNewtitle = "<a href='$newLink'>{$this->mPagetitle}</a>";
 917                         $this->mNewtitle .= " (<a href='$newEdit'>" . wfMsgHtml( $editable ? 'editold' : 'viewsourceold' ) . "</a>)";
 918                 } else {
 919                         $newLink = $this->mNewPage->escapeLocalUrl( array(
 920                                 'oldid' => $this->mNewid
 921                         ) );
 922                         $newEdit = $this->mNewPage->escapeLocalUrl( array(
 923                                 'action' => 'edit',
 924                                 'oldid' => $this->mNewid
 925                         ) );
 926                         $this->mPagetitle = htmlspecialchars( wfMsg(
 927                                 'revisionasof',
 928                                 $timestamp,
 929                                 $dateofrev,
 930                                 $timeofrev
 931                         ) );
 932
 933                         $this->mNewtitle = "<a href='$newLink'>{$this->mPagetitle}</a>";
 934                         $this->mNewtitle .= " (<a href='$newEdit'>" . wfMsgHtml( $editable ? 'editold' : 'viewsourceold' ) . "</a>)";
 935                 }
 936                 if( !$this->mNewRev->userCan(Revision::DELETED_TEXT) ) {
 937                         $this->mNewtitle = "<span class='history-deleted'>{$this->mPagetitle}</span>";
 938                 } else if ( $this->mNewRev->isDeleted(Revision::DELETED_TEXT) ) {
 939                         $this->mNewtitle = "<span class='history-deleted'>{$this->mNewtitle}</span>";
 940                 }
 941
 942                 // Load the old revision object
 943                 $this->mOldRev = false;
 944                 if( $this->mOldid ) {
 945                         $this->mOldRev = Revision::newFromId( $this->mOldid );
 946                 } elseif ( $this->mOldid === 0 ) {
 947                         $rev = $this->mNewRev->getPrevious();
 948                         if( $rev ) {
 949                                 $this->mOldid = $rev->getId();
 950                                 $this->mOldRev = $rev;
 951                         } else {
 952                                 // No previous revision; mark to show as first-version only.
 953                                 $this->mOldid = false;
 954                                 $this->mOldRev = false;
 955                         }
 956                 }/* elseif ( $this->mOldid === false ) leave mOldRev false; */
 957
 958                 if( is_null( $this->mOldRev ) ) {
 959                         return false;
 960                 }
 961
 962                 if ( $this->mOldRev ) {
 963                         $this->mOldPage = $this->mOldRev->getTitle();
 964
 965                         $t = $wgLang->timeanddate( $this->mOldRev->getTimestamp(), true );
 966                         $dateofrev = $wgLang->date( $this->mOldRev->getTimestamp(), true );
 967                         $timeofrev = $wgLang->time( $this->mOldRev->getTimestamp(), true );
 968                         $oldLink = $this->mOldPage->escapeLocalUrl( array(
 969                                 'oldid' => $this->mOldid
 970                         ) );
 971                         $oldEdit = $this->mOldPage->escapeLocalUrl( array(
 972                                 'action' => 'edit',
 973                                 'oldid' => $this->mOldid
 974                         ) );
 975                         $this->mOldPagetitle = htmlspecialchars( wfMsg( 'revisionasof', $t, $dateofrev, $timeofrev ) );
 976
 977                         $this->mOldtitle = "<a href='$oldLink'>{$this->mOldPagetitle}</a>"
 978                         . " (<a href='$oldEdit'>" . wfMsgHtml( $editable ? 'editold' : 'viewsourceold' ) . "</a>)";
 979                         // Add an "undo" link
 980                         $newUndo = $this->mNewPage->escapeLocalUrl( array(
 981                                 'action' => 'edit',
 982                                 'undoafter' => $this->mOldid,
 983                                 'undo' => $this->mNewid
 984                         ) );
 985                         $htmlLink = htmlspecialchars( wfMsg( 'editundo' ) );
 986                         $htmlTitle = $wgUser->getSkin()->tooltip( 'undo' );
 987                         if( $editable && !$this->mOldRev->isDeleted( Revision::DELETED_TEXT ) && !$this->mNewRev->isDeleted( Revision::DELETED_TEXT ) ) {
 988                                 $this->mNewtitle .= " (<a href='$newUndo' $htmlTitle>" . $htmlLink . "</a>)";
 989                         }
 990
 991                         if( !$this->mOldRev->userCan( Revision::DELETED_TEXT ) ) {
 992                                 $this->mOldtitle = '<span class="history-deleted">' . $this->mOldPagetitle . '</span>';
 993                         } else if( $this->mOldRev->isDeleted( Revision::DELETED_TEXT ) ) {
 994                                 $this->mOldtitle = '<span class="history-deleted">' . $this->mOldtitle . '</span>';
 995                         }
 996                 }
 997
 998                 return true;
 999         }
1000
1001         /**
1002          * Load the text of the revisions, as well as revision data.
1003          */
1004         function loadText() {
1005                 if ( $this->mTextLoaded == 2 ) {
1006                         return true;
1007                 } else {
1008                         // Whether it succeeds or fails, we don't want to try again
1009                         $this->mTextLoaded = 2;
1010                 }
1011
1012                 if ( !$this->loadRevisionData() ) {
1013                         return false;
1014                 }
1015                 if ( $this->mOldRev ) {
1016                         $this->mOldtext = $this->mOldRev->getText( Revision::FOR_THIS_USER );
1017                         if ( $this->mOldtext === false ) {
1018                                 return false;
1019                         }
1020                 }
1021                 if ( $this->mNewRev ) {
1022                         $this->mNewtext = $this->mNewRev->getText( Revision::FOR_THIS_USER );
1023                         if ( $this->mNewtext === false ) {
1024                                 return false;
1025                         }
1026                 }
1027                 return true;
1028         }
1029
1030         /**
1031          * Load the text of the new revision, not the old one
1032          */
1033         function loadNewText() {
1034                 if ( $this->mTextLoaded >= 1 ) {
1035                         return true;
1036                 } else {
1037                         $this->mTextLoaded = 1;
1038                 }
1039                 if ( !$this->loadRevisionData() ) {
1040                         return false;
1041                 }
1042                 $this->mNewtext = $this->mNewRev->getText( Revision::FOR_THIS_USER );
1043                 return true;
1044         }
1045 }