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[autoinstallsdev/mediawiki.git] / includes / parser / BlockLevelPass.php
diff --git a/includes/parser/BlockLevelPass.php b/includes/parser/BlockLevelPass.php
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+<?php
+
+/**
+ * This is the part of the wikitext parser which handles automatic paragraphs
+ * and conversion of start-of-line prefixes to HTML lists.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ * http://www.gnu.org/copyleft/gpl.html
+ *
+ * @file
+ * @ingroup Parser
+ */
+class BlockLevelPass {
+       private $DTopen = false;
+       private $inPre = false;
+       private $lastSection = '';
+       private $linestart;
+       private $text;
+
+       # State constants for the definition list colon extraction
+       const COLON_STATE_TEXT = 0;
+       const COLON_STATE_TAG = 1;
+       const COLON_STATE_TAGSTART = 2;
+       const COLON_STATE_CLOSETAG = 3;
+       const COLON_STATE_TAGSLASH = 4;
+       const COLON_STATE_COMMENT = 5;
+       const COLON_STATE_COMMENTDASH = 6;
+       const COLON_STATE_COMMENTDASHDASH = 7;
+       const COLON_STATE_LC = 8;
+
+       /**
+        * Make lists from lines starting with ':', '*', '#', etc.
+        *
+        * @param string $text
+        * @param bool $lineStart Whether or not this is at the start of a line.
+        * @return string The lists rendered as HTML
+        */
+       public static function doBlockLevels( $text, $lineStart ) {
+               $pass = new self( $text, $lineStart );
+               return $pass->execute();
+       }
+
+       /**
+        * Private constructor
+        */
+       private function __construct( $text, $lineStart ) {
+               $this->text = $text;
+               $this->lineStart = $lineStart;
+       }
+
+       /**
+        * If a pre or p is open, return the corresponding close tag and update
+        * the state. If no tag is open, return an empty string.
+        * @return string
+        */
+       private function closeParagraph() {
+               $result = '';
+               if ( $this->lastSection !== '' ) {
+                       $result = '</' . $this->lastSection . ">\n";
+               }
+               $this->inPre = false;
+               $this->lastSection = '';
+               return $result;
+       }
+
+       /**
+        * getCommon() returns the length of the longest common substring
+        * of both arguments, starting at the beginning of both.
+        *
+        * @param string $st1
+        * @param string $st2
+        *
+        * @return int
+        */
+       private function getCommon( $st1, $st2 ) {
+               $shorter = min( strlen( $st1 ), strlen( $st2 ) );
+
+               for ( $i = 0; $i < $shorter; ++$i ) {
+                       if ( $st1[$i] !== $st2[$i] ) {
+                               break;
+                       }
+               }
+               return $i;
+       }
+
+       /**
+        * Open the list item element identified by the prefix character.
+        *
+        * @param string $char
+        *
+        * @return string
+        */
+       private function openList( $char ) {
+               $result = $this->closeParagraph();
+
+               if ( '*' === $char ) {
+                       $result .= "<ul><li>";
+               } elseif ( '#' === $char ) {
+                       $result .= "<ol><li>";
+               } elseif ( ':' === $char ) {
+                       $result .= "<dl><dd>";
+               } elseif ( ';' === $char ) {
+                       $result .= "<dl><dt>";
+                       $this->DTopen = true;
+               } else {
+                       $result = '<!-- ERR 1 -->';
+               }
+
+               return $result;
+       }
+
+       /**
+        * Close the current list item and open the next one.
+        * @param string $char
+        *
+        * @return string
+        */
+       private function nextItem( $char ) {
+               if ( '*' === $char || '#' === $char ) {
+                       return "</li>\n<li>";
+               } elseif ( ':' === $char || ';' === $char ) {
+                       $close = "</dd>\n";
+                       if ( $this->DTopen ) {
+                               $close = "</dt>\n";
+                       }
+                       if ( ';' === $char ) {
+                               $this->DTopen = true;
+                               return $close . '<dt>';
+                       } else {
+                               $this->DTopen = false;
+                               return $close . '<dd>';
+                       }
+               }
+               return '<!-- ERR 2 -->';
+       }
+
+       /**
+        * Close the current list item identified by the prefix character.
+        * @param string $char
+        *
+        * @return string
+        */
+       private function closeList( $char ) {
+               if ( '*' === $char ) {
+                       $text = "</li></ul>";
+               } elseif ( '#' === $char ) {
+                       $text = "</li></ol>";
+               } elseif ( ':' === $char ) {
+                       if ( $this->DTopen ) {
+                               $this->DTopen = false;
+                               $text = "</dt></dl>";
+                       } else {
+                               $text = "</dd></dl>";
+                       }
+               } else {
+                       return '<!-- ERR 3 -->';
+               }
+               return $text;
+       }
+
+       /**
+        * Execute the pass.
+        * @return string
+        */
+       private function execute() {
+               $text = $this->text;
+               # Parsing through the text line by line.  The main thing
+               # happening here is handling of block-level elements p, pre,
+               # and making lists from lines starting with * # : etc.
+               $textLines = StringUtils::explode( "\n", $text );
+
+               $lastPrefix = $output = '';
+               $this->DTopen = $inBlockElem = false;
+               $prefixLength = 0;
+               $pendingPTag = false;
+               $inBlockquote = false;
+
+               foreach ( $textLines as $inputLine ) {
+                       # Fix up $lineStart
+                       if ( !$this->lineStart ) {
+                               $output .= $inputLine;
+                               $this->lineStart = true;
+                               continue;
+                       }
+                       # * = ul
+                       # # = ol
+                       # ; = dt
+                       # : = dd
+
+                       $lastPrefixLength = strlen( $lastPrefix );
+                       $preCloseMatch = preg_match( '/<\\/pre/i', $inputLine );
+                       $preOpenMatch = preg_match( '/<pre/i', $inputLine );
+                       # If not in a <pre> element, scan for and figure out what prefixes are there.
+                       if ( !$this->inPre ) {
+                               # Multiple prefixes may abut each other for nested lists.
+                               $prefixLength = strspn( $inputLine, '*#:;' );
+                               $prefix = substr( $inputLine, 0, $prefixLength );
+
+                               # eh?
+                               # ; and : are both from definition-lists, so they're equivalent
+                               #  for the purposes of determining whether or not we need to open/close
+                               #  elements.
+                               $prefix2 = str_replace( ';', ':', $prefix );
+                               $t = substr( $inputLine, $prefixLength );
+                               $this->inPre = (bool)$preOpenMatch;
+                       } else {
+                               # Don't interpret any other prefixes in preformatted text
+                               $prefixLength = 0;
+                               $prefix = $prefix2 = '';
+                               $t = $inputLine;
+                       }
+
+                       # List generation
+                       if ( $prefixLength && $lastPrefix === $prefix2 ) {
+                               # Same as the last item, so no need to deal with nesting or opening stuff
+                               $output .= $this->nextItem( substr( $prefix, -1 ) );
+                               $pendingPTag = false;
+
+                               if ( substr( $prefix, -1 ) === ';' ) {
+                                       # The one nasty exception: definition lists work like this:
+                                       # ; title : definition text
+                                       # So we check for : in the remainder text to split up the
+                                       # title and definition, without b0rking links.
+                                       $term = $t2 = '';
+                                       if ( $this->findColonNoLinks( $t, $term, $t2 ) !== false ) {
+                                               $t = $t2;
+                                               $output .= $term . $this->nextItem( ':' );
+                                       }
+                               }
+                       } elseif ( $prefixLength || $lastPrefixLength ) {
+                               # We need to open or close prefixes, or both.
+
+                               # Either open or close a level...
+                               $commonPrefixLength = $this->getCommon( $prefix, $lastPrefix );
+                               $pendingPTag = false;
+
+                               # Close all the prefixes which aren't shared.
+                               while ( $commonPrefixLength < $lastPrefixLength ) {
+                                       $output .= $this->closeList( $lastPrefix[$lastPrefixLength - 1] );
+                                       --$lastPrefixLength;
+                               }
+
+                               # Continue the current prefix if appropriate.
+                               if ( $prefixLength <= $commonPrefixLength && $commonPrefixLength > 0 ) {
+                                       $output .= $this->nextItem( $prefix[$commonPrefixLength - 1] );
+                               }
+
+                               # Close an open <dt> if we have a <dd> (":") starting on this line
+                               if ( $this->DTopen && $commonPrefixLength > 0 && $prefix[$commonPrefixLength - 1] === ':' ) {
+                                       $output .= $this->nextItem( ':' );
+                               }
+
+                               # Open prefixes where appropriate.
+                               if ( $lastPrefix && $prefixLength > $commonPrefixLength ) {
+                                       $output .= "\n";
+                               }
+                               while ( $prefixLength > $commonPrefixLength ) {
+                                       $char = $prefix[$commonPrefixLength];
+                                       $output .= $this->openList( $char );
+
+                                       if ( ';' === $char ) {
+                                               # @todo FIXME: This is dupe of code above
+                                               if ( $this->findColonNoLinks( $t, $term, $t2 ) !== false ) {
+                                                       $t = $t2;
+                                                       $output .= $term . $this->nextItem( ':' );
+                                               }
+                                       }
+                                       ++$commonPrefixLength;
+                               }
+                               if ( !$prefixLength && $lastPrefix ) {
+                                       $output .= "\n";
+                               }
+                               $lastPrefix = $prefix2;
+                       }
+
+                       # If we have no prefixes, go to paragraph mode.
+                       if ( 0 == $prefixLength ) {
+                               # No prefix (not in list)--go to paragraph mode
+                               # @todo consider using a stack for nestable elements like span, table and div
+                               $openMatch = preg_match(
+                                       '/(?:<table|<h1|<h2|<h3|<h4|<h5|<h6|<pre|<tr|'
+                                               . '<p|<ul|<ol|<dl|<li|<\\/tr|<\\/td|<\\/th)\\b/iS',
+                                       $t
+                               );
+                               $closeMatch = preg_match(
+                                       '/(?:<\\/table|<\\/h1|<\\/h2|<\\/h3|<\\/h4|<\\/h5|<\\/h6|'
+                                               . '<td|<th|<\\/?blockquote|<\\/?div|<hr|<\\/pre|<\\/p|<\\/mw:|'
+                                               . Parser::MARKER_PREFIX
+                                               . '-pre|<\\/li|<\\/ul|<\\/ol|<\\/dl|<\\/?center)\\b/iS',
+                                       $t
+                               );
+
+                               if ( $openMatch || $closeMatch ) {
+                                       $pendingPTag = false;
+                                       # @todo T7718: paragraph closed
+                                       $output .= $this->closeParagraph();
+                                       if ( $preOpenMatch && !$preCloseMatch ) {
+                                               $this->inPre = true;
+                                       }
+                                       $bqOffset = 0;
+                                       while ( preg_match( '/<(\\/?)blockquote[\s>]/i', $t,
+                                               $bqMatch, PREG_OFFSET_CAPTURE, $bqOffset )
+                                       ) {
+                                               $inBlockquote = !$bqMatch[1][0]; // is this a close tag?
+                                               $bqOffset = $bqMatch[0][1] + strlen( $bqMatch[0][0] );
+                                       }
+                                       $inBlockElem = !$closeMatch;
+                               } elseif ( !$inBlockElem && !$this->inPre ) {
+                                       if ( ' ' == substr( $t, 0, 1 )
+                                               && ( $this->lastSection === 'pre' || trim( $t ) != '' )
+                                               && !$inBlockquote
+                                       ) {
+                                               # pre
+                                               if ( $this->lastSection !== 'pre' ) {
+                                                       $pendingPTag = false;
+                                                       $output .= $this->closeParagraph() . '<pre>';
+                                                       $this->lastSection = 'pre';
+                                               }
+                                               $t = substr( $t, 1 );
+                                       } else {
+                                               # paragraph
+                                               if ( trim( $t ) === '' ) {
+                                                       if ( $pendingPTag ) {
+                                                               $output .= $pendingPTag . '<br />';
+                                                               $pendingPTag = false;
+                                                               $this->lastSection = 'p';
+                                                       } else {
+                                                               if ( $this->lastSection !== 'p' ) {
+                                                                       $output .= $this->closeParagraph();
+                                                                       $this->lastSection = '';
+                                                                       $pendingPTag = '<p>';
+                                                               } else {
+                                                                       $pendingPTag = '</p><p>';
+                                                               }
+                                                       }
+                                               } else {
+                                                       if ( $pendingPTag ) {
+                                                               $output .= $pendingPTag;
+                                                               $pendingPTag = false;
+                                                               $this->lastSection = 'p';
+                                                       } elseif ( $this->lastSection !== 'p' ) {
+                                                               $output .= $this->closeParagraph() . '<p>';
+                                                               $this->lastSection = 'p';
+                                                       }
+                                               }
+                                       }
+                               }
+                       }
+                       # somewhere above we forget to get out of pre block (T2785)
+                       if ( $preCloseMatch && $this->inPre ) {
+                               $this->inPre = false;
+                       }
+                       if ( $pendingPTag === false ) {
+                               $output .= $t;
+                               if ( $prefixLength === 0 ) {
+                                       $output .= "\n";
+                               }
+                       }
+               }
+               while ( $prefixLength ) {
+                       $output .= $this->closeList( $prefix2[$prefixLength - 1] );
+                       --$prefixLength;
+                       if ( !$prefixLength ) {
+                               $output .= "\n";
+                       }
+               }
+               if ( $this->lastSection !== '' ) {
+                       $output .= '</' . $this->lastSection . '>';
+                       $this->lastSection = '';
+               }
+
+               return $output;
+       }
+
+       /**
+        * Split up a string on ':', ignoring any occurrences inside tags
+        * to prevent illegal overlapping.
+        *
+        * @param string $str The string to split
+        * @param string &$before Set to everything before the ':'
+        * @param string &$after Set to everything after the ':'
+        * @throws MWException
+        * @return string The position of the ':', or false if none found
+        */
+       private function findColonNoLinks( $str, &$before, &$after ) {
+               if ( !preg_match( '/:|<|-\{/', $str, $m, PREG_OFFSET_CAPTURE ) ) {
+                       # Nothing to find!
+                       return false;
+               }
+
+               if ( $m[0][0] === ':' ) {
+                       # Easy; no tag nesting to worry about
+                       $colonPos = $m[0][1];
+                       $before = substr( $str, 0, $colonPos );
+                       $after = substr( $str, $colonPos + 1 );
+                       return $colonPos;
+               }
+
+               # Ugly state machine to walk through avoiding tags.
+               $state = self::COLON_STATE_TEXT;
+               $ltLevel = 0;
+               $lcLevel = 0;
+               $len = strlen( $str );
+               for ( $i = $m[0][1]; $i < $len; $i++ ) {
+                       $c = $str[$i];
+
+                       switch ( $state ) {
+                       case self::COLON_STATE_TEXT:
+                               switch ( $c ) {
+                               case "<":
+                                       # Could be either a <start> tag or an </end> tag
+                                       $state = self::COLON_STATE_TAGSTART;
+                                       break;
+                               case ":":
+                                       if ( $ltLevel === 0 ) {
+                                               # We found it!
+                                               $before = substr( $str, 0, $i );
+                                               $after = substr( $str, $i + 1 );
+                                               return $i;
+                                       }
+                                       # Embedded in a tag; don't break it.
+                                       break;
+                               default:
+                                       # Skip ahead looking for something interesting
+                                       if ( !preg_match( '/:|<|-\{/', $str, $m, PREG_OFFSET_CAPTURE, $i ) ) {
+                                               # Nothing else interesting
+                                               return false;
+                                       }
+                                       if ( $m[0][0] === '-{' ) {
+                                               $state = self::COLON_STATE_LC;
+                                               $lcLevel++;
+                                               $i = $m[0][1] + 1;
+                                       } else {
+                                               # Skip ahead to next interesting character.
+                                               $i = $m[0][1] - 1;
+                                       }
+                                       break;
+                               }
+                               break;
+                       case self::COLON_STATE_LC:
+                               # In language converter markup -{ ... }-
+                               if ( !preg_match( '/-\{|\}-/', $str, $m, PREG_OFFSET_CAPTURE, $i ) ) {
+                                       # Nothing else interesting to find; abort!
+                                       # We're nested in language converter markup, but there
+                                       # are no close tags left.  Abort!
+                                       break 2;
+                               } elseif ( $m[0][0] === '-{' ) {
+                                       $i = $m[0][1] + 1;
+                                       $lcLevel++;
+                               } elseif ( $m[0][0] === '}-' ) {
+                                       $i = $m[0][1] + 1;
+                                       $lcLevel--;
+                                       if ( $lcLevel === 0 ) {
+                                               $state = self::COLON_STATE_TEXT;
+                                       }
+                               }
+                               break;
+                       case self::COLON_STATE_TAG:
+                               # In a <tag>
+                               switch ( $c ) {
+                               case ">":
+                                       $ltLevel++;
+                                       $state = self::COLON_STATE_TEXT;
+                                       break;
+                               case "/":
+                                       # Slash may be followed by >?
+                                       $state = self::COLON_STATE_TAGSLASH;
+                                       break;
+                               default:
+                                       # ignore
+                               }
+                               break;
+                       case self::COLON_STATE_TAGSTART:
+                               switch ( $c ) {
+                               case "/":
+                                       $state = self::COLON_STATE_CLOSETAG;
+                                       break;
+                               case "!":
+                                       $state = self::COLON_STATE_COMMENT;
+                                       break;
+                               case ">":
+                                       # Illegal early close? This shouldn't happen D:
+                                       $state = self::COLON_STATE_TEXT;
+                                       break;
+                               default:
+                                       $state = self::COLON_STATE_TAG;
+                               }
+                               break;
+                       case self::COLON_STATE_CLOSETAG:
+                               # In a </tag>
+                               if ( $c === ">" ) {
+                                       if ( $ltLevel > 0 ) {
+                                               $ltLevel--;
+                                       } else {
+                                               # ignore the excess close tag, but keep looking for
+                                               # colons. (This matches Parsoid behavior.)
+                                               wfDebug( __METHOD__ . ": Invalid input; too many close tags\n" );
+                                       }
+                                       $state = self::COLON_STATE_TEXT;
+                               }
+                               break;
+                       case self::COLON_STATE_TAGSLASH:
+                               if ( $c === ">" ) {
+                                       # Yes, a self-closed tag <blah/>
+                                       $state = self::COLON_STATE_TEXT;
+                               } else {
+                                       # Probably we're jumping the gun, and this is an attribute
+                                       $state = self::COLON_STATE_TAG;
+                               }
+                               break;
+                       case self::COLON_STATE_COMMENT:
+                               if ( $c === "-" ) {
+                                       $state = self::COLON_STATE_COMMENTDASH;
+                               }
+                               break;
+                       case self::COLON_STATE_COMMENTDASH:
+                               if ( $c === "-" ) {
+                                       $state = self::COLON_STATE_COMMENTDASHDASH;
+                               } else {
+                                       $state = self::COLON_STATE_COMMENT;
+                               }
+                               break;
+                       case self::COLON_STATE_COMMENTDASHDASH:
+                               if ( $c === ">" ) {
+                                       $state = self::COLON_STATE_TEXT;
+                               } else {
+                                       $state = self::COLON_STATE_COMMENT;
+                               }
+                               break;
+                       default:
+                               throw new MWException( "State machine error in " . __METHOD__ );
+                       }
+               }
+               if ( $ltLevel > 0 || $lcLevel > 0 ) {
+                       wfDebug(
+                               __METHOD__ . ": Invalid input; not enough close tags " .
+                               "(level $ltLevel/$lcLevel, state $state)\n"
+                       );
+                       return false;
+               }
+               return false;
+       }
+}