mediawiki-extensions-Echo/includes/DiscussionParser.php

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<?php
abstract class EchoDiscussionParser {
static $timestampRegex;
static $headerRegex = '^\=\=\s*([^=].*)\s*\=\=$';
static $revisionInterpretationCache = array();
/**
* Given a Revision object, generates EchoEvent objects for
* the discussion-related actions that occurred in that Revision.
*
* @param $revision Revision object
* @return null
*/
static function generateEventsForRevision( $revision ) {
$interpretation = self::getChangeInterpretationForRevision( $revision );
$createdEvents = false;
// use slave database if there is a previous revision
if ( $revision->getPrevious() ) {
$title = Title::newFromID( $revision->getPage() );
// use master database for new page
} else {
$title = Title::newFromID( $revision->getPage(), Title::GAID_FOR_UPDATE );
}
// not a valid title
if ( !$title ) {
return;
}
$userID = $revision->getUser();
$userName = $revision->getUserText();
$user = $userID != 0 ? User::newFromId( $userID ) : User::newFromName( $userName, false );
foreach ( $interpretation as $action ) {
// These two event types are disabled temporarily, there is no need to process them
/*
if ( $action['type'] == 'add-comment' ) {
$fullSection = $action['full-section'];
$header = self::extractHeader( $fullSection );
EchoEvent::create( array(
'type' => 'add-comment',
'title' => $title,
'extra' => array(
'revid' => $revision->getID(),
'section-title' => $header,
'content' => $action['content'],
),
'agent' => $user,
) );
$createdEvents = true;
} elseif ( $action['type'] == 'new-section-with-comment' ) {
$content = $action['content'];
$header = self::extractHeader( $content );
EchoEvent::create( array(
'type' => 'add-talkpage-topic',
'title' => $title,
'extra' => array(
'revid' => $revision->getID(),
'section-title' => $header,
'content' => $content,
),
'agent' => $user,
) );
$createdEvents = true;
}
*/
}
if ( !$createdEvents && $title->getNamespace() == NS_USER_TALK ) {
$notifyUser = User::newFromName( $title->getText() );
if ( $notifyUser && $notifyUser->getID() ) {
EchoEvent::create( array(
'type' => 'edit-user-talk',
'title' => $title,
'extra' => array( 'revid' => $revision->getID() ),
'agent' => $user,
) );
}
}
}
/**
* Given a Revision object, determines which users are interested
* in related EchoEvents.
*
* @param $revision Revision object.
* @return Array of User objects
*/
static function getNotifiedUsersForComment( $revision ) {
$interpretation = self::getChangeInterpretationForRevision( $revision );
$users = array();
foreach ( $interpretation as $action ) {
if ( $action['type'] == 'add-comment' ) {
$fullSection = $action['full-section'];
$interestedUsers = array_keys( self::extractSignatures( $fullSection ) );
foreach ( $interestedUsers as $userName ) {
$user = User::newFromName( $userName );
// Deliberately ignoring anonymous users
if ( $user && $user->getID() ) {
$users[$user->getID()] = $user;
}
}
}
}
if ( $revision->getTitle()->getNamespace() == NS_USER_TALK ) {
$userName = $revision->getTitle()->getText();
$user = User::newFromName( $userName );
if ( $user ) {
$users[$user->getID()] = $user;
}
}
return $users;
}
/**
* Given a Revision object, returns a talk-page-centric interpretation
* of the changes made in it.
*
* @param $revision Revision object
* @see EchoDiscussionParser::interpretDiff
* @return Array, see interpretDiff for details.
*/
static function getChangeInterpretationForRevision( $revision ) {
if ( $revision->getID() && isset( self::$revisionInterpretationCache[$revision->getID()] ) ) {
return self::$revisionInterpretationCache[$revision->getID()];
}
$userID = $revision->getUser();
$userName = $revision->getUserText();
$user = $userID != 0 ? User::newFromId( $userID ) : User::newFromName( $userName, false );
$prevText = '';
if ( $revision->getParentId() ) {
$prevRevision = Revision::newFromId( $revision->getParentId() );
if ( $prevRevision ) {
$prevText = $prevRevision->getText();
}
}
$changes = self::getMachineReadableDiff( $prevText, $revision->getText() );
$output = self::interpretDiff( $changes, $user->getName() );
self::$revisionInterpretationCache[$revision->getID()] = $output;
return $output;
}
/**
* Given a machine-readable diff, interprets the changes
* in terms of discussion page actions
*
* @todo Expand recognisable actions.
* @param $changes array Output of EchoEvent::getMachineReadableDiff
* @param $user User name
* @return Array of associative arrays.
* Each entry represents an action, which is classified in the 'action' field.
* All types contain a 'content' field except 'unknown'
* (which instead passes through the machine-readable diff in 'details')
* and 'unknown-change' (which provides 'new_content' and 'old_content')
* action may be:
* - add-comment: A comment signed by the user is added to an
* existing section.
* - new-section-with-comment: A new section is added, containing
* a single comment signed by the user in question.
* - unknown-signed-addition: Some signed content is added, but it
* includes section headers, is signed by another user or
* otherwise confuses the interpretation engine.
* - unknown-multi-signed-addition: Some signed content is added,
* but it contains multiple signatures.
* - unknown-unsigned-addition: Some content is added, but it is
* unsigned.
* - unknown-subtraction: Some content was removed. These actions are
* not currently analysed.
* - unknown-change: Some content was replaced with other content.
* These actions are not currently analysed.
* - unknown: Unrecognised change type.
*/
static function interpretDiff( $changes, $user ) {
// One extra item in $changes for _info
$actions = array();
foreach ( $changes as $index => $change ) {
if ( !is_numeric( $index ) ) {
continue;
}
if ( !$change['action'] ) {
// Unknown action; skip
continue;
}
if ( $change['action'] == 'add' ) {
$content = trim( $change['content'] );
$startSection = preg_match( "/\A" . self::$headerRegex . '/um', $content );
$sectionCount = self::getSectionCount( $content );
$signedUsers = array_keys( self::extractSignatures( $content ) );
if (
count( $signedUsers ) == 1 &&
in_array( $user, $signedUsers )
) {
if ( $sectionCount === 0 ) {
$fullSection = self::getFullSection( $changes['_info']['rhs'], $change['right-pos'] );
$actions[] = array(
'type' => 'add-comment',
'content' => $content,
'full-section' => $fullSection,
);
} elseif ( $startSection && $sectionCount === 1 ) {
$actions[] = array(
'type' => 'new-section-with-comment',
'content' => $content,
);
} else {
$actions[] = array(
'type' => 'unknown-signed-addition',
'content' => $content,
);
}
} elseif ( count( $signedUsers ) >= 1 ) {
$actions[] = array(
'type' => 'unknown-multi-signed-addition',
'content' => $content,
);
} else {
$actions[] = array(
'type' => 'unknown-unsigned-addition',
'content' => $content,
);
}
} elseif ( $change['action'] == 'subtract' ) {
$actions[] = array(
'type' => 'unknown-subtraction',
'content' => $change['content'],
);
} elseif ( $change['action'] == 'change' ) {
$actions[] = array(
'type' => 'unknown-change',
'old_content' => $change['old_content'],
'new_content' => $change['new_content'],
);
} else {
$actions[] = array(
'type' => 'unknown',
'details' => $change,
);
}
}
// $actions['_diff'] = $changes;
// unset( $actions['_diff']['_info'] );
return $actions;
}
/**
* Finds the section that a given line is in.
*
* @param $lines Array of lines in the page.
* @param $offset int The line to find the full section for.
* @return string Content of the section.
*/
static function getFullSection( $lines, $offset ) {
$content = $lines[$offset - 1];
$headerRegex = '/' . self::$headerRegex . '/um';
// Expand backwards...
$continue = !preg_match( $headerRegex, $lines[$offset - 1] );
$i = $offset - 1;
while ( $continue && $i > 0 ) {
--$i;
$line = $lines[$i];
$content = "$line\n$content";
if ( preg_match( $headerRegex, $line ) ) {
$continue = false;
}
}
// And then forwards...
$continue = true;
$i = $offset - 1;
while ( $continue && $i < count( $lines ) - 1 ) {
++$i;
$line = $lines[$i];
if ( preg_match( $headerRegex, $line ) ) {
$continue = false;
} else {
$content .= "\n$line";
}
}
return $content;
}
/**
* Gets the number of section headers in a string.
*
* @param $text string The text.
* @return int Number of section headers found.
*/
static function getSectionCount( $text ) {
$text = trim( $text );
$matches = array();
preg_match_all( '/' . self::$headerRegex . '/um', $text, $matches );
return count( $matches[0] );
}
/**
* Gets the title of a section
*
* @param $text string The text of the section.
* @return string The title of the section.
*/
static function extractHeader( $text ) {
$text = trim( $text );
$matches = array();
if ( !preg_match( '/' . self::$headerRegex . '/um', $text, $matches ) ) {
return false;
}
return trim( $matches[1] );
}
/**
* Strips out a signature if possible.
*
* @param $text string The wikitext to strip
* @return string
*/
static function stripSignature( $text ) {
$timestampPos = self::getTimestampPosition( $text );
if ( $timestampPos === false ) {
return $text;
}
$output = self::getUserFromLine( $text, $timestampPos );
if ( $output === false ) {
return substr( $text, 0, $timestampPos );
}
// Strip off signature with HTML truncation method.
// This way tags which are opened will be closed.
global $wgContLang;
$truncated_text = $wgContLang->truncateHtml( $text, $output[0], '' );
return $truncated_text;
}
/**
* Strips unnecessary indentation and so on from comments
*
* @param $text string The text to strip from
* @return string Stripped wikitext
*/
static function stripIndents( $text ) {
// First strip all indentation from the beginning of lines
$text = preg_replace( '/^\s*\:+/m', '', $text );
// Now if there is only one list item, strip that too
$listRegex = '/^\s*(?:[\:#*]\s*)*[#*]/m';
$matches = array();
if ( preg_match_all( $listRegex, $text, $matches ) ) {
if ( count( $matches ) == 1 ) {
$text = preg_replace( $listRegex, '', $text );
}
}
return $text;
}
/**
* Strips out a section header
* @param $text string The text to strip out the section header from.
* @return string: The same text, with the section header stripped out.
*/
static function stripHeader( $text ) {
$text = preg_replace( '/' . self::$headerRegex . '/um', '', $text );
return $text;
}
/**
* Determines whether the input is a signed comment.
*
* @param $text string The text to check.
* @param $user User|bool If set, will only return true if the comment is
* signed by this user.
* @return bool: true or false.
*/
static function isSignedComment( $text, $user = false ) {
$timestampPos = self::getTimestampPosition( $text );
if ( $timestampPos === false ) {
return false;
}
$userData = self::getUserFromLine( $text, $timestampPos );
if ( $userData === false ) {
return false;
} elseif ( $user === false ) {
return true;
}
list( $signaturePos, $foundUser ) = $userData;
return User::getCanonicalName( $foundUser, false ) === User::getCanonicalName( $user, false );
}
/**
* Finds the start position, if any, of the timestamp on a line
*
* @param $line string The line to search for a signature on
* @return int|bool Integer position
*/
static function getTimestampPosition( $line ) {
$timestampRegex = self::getTimestampRegex();
$endOfLine = self::getLineEndingRegex();
$tsMatches = array();
if ( !preg_match(
"/$timestampRegex$endOfLine/mu",
$line,
$tsMatches,
PREG_OFFSET_CAPTURE
) ) {
return false;
}
return $tsMatches[0][0];
}
/**
* Finds differences between $oldText and $newText
* and returns the result in a machine-readable format.
*
* @param $oldText string The "left hand side" of the diff.
* @param $newText string The "right hand side" of the diff.
* @throws MWException
* @return Array of changes.
* Each change consists of:
* * An 'action', one of:
* - add
* - subtract
* - change
* * 'content' that was added or removed, or in the case
* of a change, 'old_content' and 'new_content'
* * 'left_pos' and 'right_pos' (in lines) of the change.
*/
static function getMachineReadableDiff( $oldText, $newText ) {
$oldText = trim( $oldText ) . "\n";
$newText = trim( $newText ) . "\n";
$diff = wfDiff( $oldText, $newText, '-u -w' );
$old_lines = explode( "\n", $oldText );
$new_lines = explode( "\n", $newText );
// First break down the diff into additions and subtractions
$diff_lines = explode( "\n", $diff );
$left_pos = 0;
$right_pos = 0;
$changes = array();
$change_run = false;
$sub_lines = 0;
for ( $i = 0; $i < count( $diff_lines ); ++$i ) {
$line = $diff_lines[$i];
if ( strlen( $line ) == 0 ) {
continue;
}
$line_type = $line[0];
if ( $line_type == ' ' ) {
++$left_pos;
++$right_pos;
} elseif ( $line_type == '@' ) {
list( $at, $lhs_pos, $rhs_pos, $at ) = explode( ' ', $line );
$lhs_pos = substr( $lhs_pos, 1 );
$rhs_pos = substr( $rhs_pos, 1 );
list( $left_pos ) = explode( ',', $lhs_pos );
list( $right_pos ) = explode( ',', $rhs_pos );
$change_run = false;
} elseif ( $line_type == '-' ) {
$subtracted_line = substr( $line, 1 );
if ( trim( $subtracted_line ) === '' ) {
++$left_pos;
continue;
}
if ( $change_run && $changes[$change_run]['action'] == 'subtract' ) {
++$sub_lines;
$changes[$change_run]['content'] .= "\n" . $subtracted_line;
} else {
$sub_lines = 1;
$changes[] = array(
'action' => 'subtract',
'left-pos' => $left_pos,
'right-pos' => $right_pos,
'content' => $subtracted_line,
);
$change_run = count( $changes ) - 1;
}
// Consistency check
if ( $old_lines[$left_pos - 1] != $subtracted_line ) {
throw new MWException( "Left offset consistency error.\nOffset: $right_pos\nExpected: {$old_lines[$left_pos-1]}\nActual: $subtracted_line" );
}
++$left_pos;
} elseif ( $line_type == '+' ) {
$added_line = substr( $line, 1 );
if ( $change_run !== false && $changes[$change_run]['action'] == 'add' ) {
$changes[$change_run]['content'] .= "\n" . $added_line;
} elseif ( $change_run !== false && $changes[$change_run]['action'] == 'subtract' ) {
$changes[$change_run]['action'] = 'change';
$changes[$change_run]['old_content'] = $changes[$change_run]['content'];
$changes[$change_run]['new_content'] = $added_line;
--$sub_lines;
unset( $changes[$change_run]['content'] );
} elseif ( $change_run !== false && $changes[$change_run]['action'] == 'change' && $sub_lines > 0 ) {
--$sub_lines;
$changes[$change_run]['new_content'] .= "\n" . $added_line;
} else {
$changes[] = array(
'action' => 'add',
'left-pos' => $left_pos,
'right-pos' => $right_pos,
'content' => $added_line,
);
$change_run = count( $changes ) - 1;
}
// Consistency check
if ( $new_lines[$right_pos - 1] != $added_line ) {
throw new MWException( "Right offset consistency error.\nOffset: $right_pos\nExpected: {$new_lines[$right_pos-1]}\nActual: $added_line\n" );
}
++$right_pos;
}
}
$changes['_info'] = array(
'lhs-length' => count( $old_lines ),
'rhs-length' => count( $new_lines ),
'lhs' => $old_lines,
'rhs' => $new_lines,
);
return $changes;
}
/**
* Finds and extracts signatures in $text
*
* @param $text string The text in which to look for signed comments.
* @return array. Associative array, the key is the username, the value
* is the last signature that was found.
*/
static function extractSignatures( $text ) {
$lines = explode( "\n", $text );
$timestampRegex = self::getTimestampRegex();
$endOfLine = self::getLineEndingRegex();
$output = array();
$lineNumber = 0;
foreach ( $lines as $line ) {
++$lineNumber;
$tsMatches = array();
if ( !preg_match(
"/$timestampRegex$endOfLine/mu",
$line,
$tsMatches,
PREG_OFFSET_CAPTURE
) ) {
// Ignore lines that don't finish with a timestamp
// print "I\tNo timestamp\n";
// print "$line\n";
continue;
}
// Now that we know we have a timestamp, look for
// the last user link on the line.
$userData = self::getUserFromLine( $line, $tsMatches[0][0] );
if ( $userData === false ) {
// print "F\t$lineNumber\t$line\n";
continue;
} else {
// print "S\t$lineNumber\n";
}
list( $signaturePos, $user ) = $userData;
$signature = substr( $line, $signaturePos );
$output[$user] = $signature;
}
return $output;
}
/**
* From a line in a wiki page, determine which user, if any,
* has signed it.
*
* @param $line string The line.
* @param $timestampPos int The offset of the start of the timestamp.
* @return bool|array false for none, Array for success.
* - First element is the position of the signature.
* - Second element is the normalised user name.
*/
static function getUserFromLine( $line, $timestampPos ) {
global $wgContLang;
$possiblePrefixes = array( // Later entries have a higher precedence
'[[' . $wgContLang->getNsText( NS_USER ) . ':',
'[[' . $wgContLang->getNsText( NS_USER_TALK ) . ':',
'[[' . SpecialPage::getTitleFor( 'Contributions' )->getPrefixedText() . '/',
);
foreach ( $possiblePrefixes as $prefix ) {
if ( strpos( $prefix, '_' ) !== false ) {
$possiblePrefixes[] = str_replace( '_', ' ', $prefix );
}
}
$winningUser = false;
$winningPos = false;
// Look for the leftmost link to the rightmost user
foreach ( $possiblePrefixes as $prefix ) {
$output = self::getLinkFromLine( $line, $prefix );
if ( $output === false ) {
continue;
} else {
list( $pos, $user ) = $output;
}
// Couldn't be a signature
if ( ( $timestampPos - $pos ) > 255 ) {
continue;
}
if (
$winningPos === false ||
( $pos > $winningPos && $user !== $winningUser ) ||
(
$pos < $winningPos &&
$user === $winningUser
)
) {
$winningPos = $pos;
$winningUser = ucfirst( trim( $user ) );
}
}
if ( $winningUser === false ) {
// print "E\tNo winning user\n";
return false;
}
return array( $winningPos, $winningUser );
}
/**
* Find the last link beginning with a given prefix on a line.
*
* @param $line string The line to search.
* @param $linkPrefix string The prefix to search for.
* @param $failureOffset bool
* @return bool false for failure, array for success.
* - First element is the string offset of the link.
* - Second element is the user the link refers to.
*/
static function getLinkFromLine( $line, $linkPrefix, $failureOffset = false ) {
$offset = 0;
// If extraction failed at another offset, try again.
if ( $failureOffset !== false ) {
$offset = $failureOffset - strlen( $line ) - 1;
}
$linkPos = strripos( $line, $linkPrefix, $offset );
if ( $linkPos === false ) {
// print "I\tNo match for $linkPrefix\n";
return false;
}
$linkUser = self::extractUserFromLink( $line, $linkPrefix, $linkPos );
if ( $linkUser === false ) {
// print "E\tExtraction failed\t$linkPrefix\n";
// Look for another place.
return self::getLinkFromLine( $line, $linkPrefix, $linkPos );
} else {
return array( $linkPos, $linkUser );
}
}
/**
* Given text including a link, gives the user that that link refers to
*
* @param $text string The text to extract from.
* @param $prefix string The link prefix that was used to find the link.
* @param $offset int Optionally, the offset of the start of the link.
* @return bool|string Type description
*/
static function extractUserFromLink( $text, $prefix, $offset = 0 ) {
$userPart = substr( $text, strlen( $prefix ) + $offset );
$userMatches = array();
if ( !preg_match(
'/^[^\|\]\#]+/u',
$userPart,
$userMatches
) ) {
// user link is invalid
// print "I\tUser link invalid\t$userPart\n";
// print "E\tCannot find user info to extract\n";
return false;
}
$user = $userMatches[0];
if (
!User::isIP( $user ) &&
User::getCanonicalName( $user ) === false
) {
// Not a real username
// print "E\tInvalid username\n";
return false;
}
return User::getCanonicalName( $userMatches[0], false );
}
/**
* Gets a regular expression fragmentmatching characters that
* can appear in a line after the signature.
*
* @return String regular expression fragment.
*/
static function getLineEndingRegex() {
$ignoredEndings = array(
'\s*',
preg_quote( '}' ),
preg_quote( '{' ),
'\<[^\>]+\>',
preg_quote( '{{' ) . '[^}]+' . preg_quote( '}}' ),
);
$regex = '(?:' . implode( '|', $ignoredEndings ) . ')*';
return $regex;
}
/**
* Gets a regular expression that will match this wiki's
* timestamps as given by ~~~~.
*
* @throws MWException
* @return String regular expression fragment.
*/
static function getTimestampRegex() {
if ( self::$timestampRegex !== null ) {
return self::$timestampRegex;
}
// Step 1: Get an exemplar timestamp
$title = Title::newMainPage();
$user = User::newFromName( 'Test' );
$options = new ParserOptions;
global $wgParser;
$exemplarTimestamp =
$wgParser->preSaveTransform( '~~~~~', $title, $user, $options );
// Step 2: Generalise it
// Trim off the timezone to replace at the end
$output = $exemplarTimestamp;
$tzRegex = '/\s*\(\w+\)\s*$/';
$tzMatches = array();
preg_match( $tzRegex, $output, $tzMatches );
$output = preg_replace( $tzRegex, '', $output );
$output = preg_quote( $output, '/' );
$output = preg_replace( '/[^\d\W]+/u', '[^\d\W]+', $output );
$output = preg_replace( '/\d+/u', '\d+', $output );
$output .= preg_quote( $tzMatches[0] );
if ( !preg_match( "/$output/u", $exemplarTimestamp ) ) {
throw new MWException( "Timestamp regex does not match exemplar" );
}
self::$timestampRegex = $output;
return $output;
}
/**
* This function returns plain text snippet, it also removes html tag,
* template from text content
* @param $text string
* @param $length int default 150
* @return string
*/
static function getTextSnippet( $text, $length = 150 ) {
global $wgLang;
$text = strip_tags( $text );
$attempt = 0;
// 10 attempts at most, the logic here is to find the first }} and
// find the matching {{ for that }}
while ( $attempt < 10 ) {
$closeCurPos = strpos( $text, '}}' );
if ( $closeCurPos === false ) {
break;
}
$tempStr = substr( $text, 0, $closeCurPos + 2 );
$openCurPos = strrpos( $tempStr, '{{' );
if ( $openCurPos === false ) {
$text = substr_replace( $text, '', $closeCurPos, 2 );
} else {
$text = substr_replace( $text, '', $openCurPos, $closeCurPos - $openCurPos + 2 );
}
$attempt++;
}
$text = trim( strip_tags( htmlspecialchars_decode( MessageCache::singleton()->parse( $text )->getText() ) ) );
// strip out non-useful data for snippet
$text = str_replace( array( '{', '}' ), '', $text );
return $wgLang->truncate( $text, $length );
}
}