mediawiki-extensions-Discus.../includes/CommentParser.php

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<?php
namespace MediaWiki\Extension\DiscussionTools;
use Config;
use DateInterval;
use DateTime;
use DateTimeImmutable;
use DateTimeZone;
use DOMElement;
use DOMNode;
use DOMText;
use IP;
use Language;
use MediaWiki\MediaWikiServices;
use MWException;
use Title;
// TODO clean up static vs non-static
// TODO consider making timestamp parsing not a returned function
class CommentParser {
private const SIGNATURE_SCAN_LIMIT = 100;
/** @var DOMElement */
private $rootNode;
/** @var ThreadItem[] */
private $threadItems;
/** @var CommentItem[] */
private $commentItems;
/** @var ThreadItem[][] */
private $threadItemsByName;
/** @var ThreadItem[] */
private $threadItemsById;
/** @var HeadingItem[] */
private $threads;
/** @var Config */
private $config;
/** @var Language */
private $language;
private $dateFormat;
private $digits;
/** @var string[][] */
private $contLangMessages;
private $localTimezone;
private $timezones;
/**
* @param DomElement $rootNode Root node of content to parse
* @param Language $language Content language
* @param Config $config
* @param array $data
*/
public function __construct( DOMElement $rootNode, Language $language, Config $config, array $data = [] ) {
$this->rootNode = $rootNode;
$this->config = $config;
$this->language = $language;
if ( !$data ) {
// TODO: Instead of passing data used for mocking, mock the methods that fetch the data.
$data = Data::getLocalData( null, $config, $language );
}
$this->dateFormat = $data['dateFormat'];
$this->digits = $data['digits'];
$this->contLangMessages = $data['contLangMessages'];
$this->localTimezone = $data['localTimezone'];
$this->timezones = $data['timezones'];
}
/**
* @param DomElement $rootNode
* @return CommentParser
*/
public static function newFromGlobalState( DOMElement $rootNode ) : CommentParser {
return new static(
$rootNode,
MediaWikiServices::getInstance()->getContentLanguage(),
MediaWikiServices::getInstance()->getMainConfig()
);
}
/**
* Check whether the node is a comment separator (instead of a part of the comment).
*
* @param DOMNode $node
* @return bool
*/
private static function isCommentSeparator( DOMNode $node ) {
return $node instanceof DOMElement && (
// Empty paragraphs (`<p><br></p>`) between indented comments mess up indentation detection
strtolower( $node->nodeName ) === 'br' ||
// Horizontal line
strtolower( $node->nodeName ) === 'hr' ||
// {{outdent}} templates
$node->getAttribute( 'class' ) === 'outdent-template'
);
}
/**
* Return the next leaf node in the tree order that is likely a part of a discussion comment,
* rather than some boring "separator" element.
*
* Currently, this can return a Text node with content other than whitespace, or an Element node
* that is a "void element" or "text element", except some special cases that we treat as comment
* separators (isCommentSeparator()).
*
* @param DOMNode $node Node to start searching at. This node's children are ignored.
* @return DOMNode
*/
private function nextInterestingLeafNode( DOMNode $node ) : DOMNode {
$rootNode = $this->rootNode;
$treeWalker = new TreeWalker(
$rootNode,
NodeFilter::SHOW_ELEMENT | NodeFilter::SHOW_TEXT,
function ( $n ) use ( $node, $rootNode ) {
// Ignore this node and its descendants
// (unless it's the root node, this is a special case for "fakeHeading" handling)
if ( $node !== $rootNode && ( $n === $node || $n->parentNode === $node ) ) {
return NodeFilter::FILTER_REJECT;
}
// Ignore some elements usually used as separators or headers (and their descendants)
if ( self::isCommentSeparator( $n ) ) {
return NodeFilter::FILTER_REJECT;
}
// Ignore nodes with no rendering that mess up our indentation detection
if ( CommentUtils::isRenderingTransparentNode( $n ) ) {
return NodeFilter::FILTER_REJECT;
}
if (
(
$n->nodeType === XML_TEXT_NODE &&
CommentUtils::htmlTrim( $n->nodeValue ) !== ''
) ||
(
$n->nodeType === XML_CDATA_SECTION_NODE &&
CommentUtils::htmlTrim( $n->nodeValue ) !== ''
) ||
(
CommentUtils::cantHaveElementChildren( $n )
)
) {
return NodeFilter::FILTER_ACCEPT;
}
return NodeFilter::FILTER_SKIP;
}
);
$treeWalker->currentNode = $node;
$treeWalker->nextNode();
if ( !$treeWalker->currentNode ) {
throw new MWException( 'nextInterestingLeafNode not found' );
}
return $treeWalker->currentNode;
}
/**
* @param string[] $values Values to match
* @return string Regular expression
*/
private static function regexpAlternateGroup( array $values ) : string {
return '(' . implode( '|', array_map( function ( string $x ) {
return preg_quote( $x, '/' );
}, $values ) ) . ')';
}
/**
* Get text of localisation messages in content language.
*
* @param string $contLangVariant Content language variant
* @param string[] $messages Message keys
* @return string[] Message values
*/
private function getMessages( string $contLangVariant, array $messages ) : array {
return array_map( function ( string $key ) use ( $contLangVariant ) {
return $this->contLangMessages[$contLangVariant][$key];
}, $messages );
}
/**
* Get a regexp that matches timestamps generated using the given date format.
*
* This only supports format characters that are used by the default date format in any of
* MediaWiki's languages, namely: D, d, F, G, H, i, j, l, M, n, Y, xg, xkY (and escape characters),
* and only dates when MediaWiki existed, let's say 2000 onwards (Thai dates before 1941 are
* complicated).
*
* @param string $contLangVariant Content language variant
* @param string $format Date format
* @param string $digitsRegexp Regular expression matching a single localised digit, e.g. '[0-9]'
* @param array $tzAbbrs Associative array mapping localised timezone abbreviations to
* IANA abbreviations, for the local timezone, e.g. [ 'EDT' => 'EDT', 'EST' => 'EST' ]
* @return string Regular expression
*/
private function getTimestampRegexp(
string $contLangVariant, string $format, string $digitsRegexp, array $tzAbbrs
) : string {
$formatLength = strlen( $format );
$s = '';
// Adapted from Language::sprintfDate()
for ( $p = 0; $p < $formatLength; $p++ ) {
$num = false;
$code = $format[ $p ];
if ( $code === 'x' && $p < $formatLength - 1 ) {
$code .= $format[++$p];
}
if ( $code === 'xk' && $p < $formatLength - 1 ) {
$code .= $format[++$p];
}
switch ( $code ) {
case 'xx':
$s .= 'x';
break;
case 'xg':
$s .= self::regexpAlternateGroup(
$this->getMessages( $contLangVariant, Language::MONTH_GENITIVE_MESSAGES )
);
break;
case 'd':
$num = '2';
break;
case 'D':
$s .= self::regexpAlternateGroup(
$this->getMessages( $contLangVariant, Language::WEEKDAY_ABBREVIATED_MESSAGES )
);
break;
case 'j':
$num = '1,2';
break;
case 'l':
$s .= self::regexpAlternateGroup(
$this->getMessages( $contLangVariant, Language::WEEKDAY_MESSAGES )
);
break;
case 'F':
$s .= self::regexpAlternateGroup(
$this->getMessages( $contLangVariant, Language::MONTH_MESSAGES )
);
break;
case 'M':
$s .= self::regexpAlternateGroup(
$this->getMessages( $contLangVariant, Language::MONTH_ABBREVIATED_MESSAGES )
);
break;
case 'n':
$num = '1,2';
break;
case 'Y':
$num = '4';
break;
case 'xkY':
$num = '4';
break;
case 'G':
$num = '1,2';
break;
case 'H':
$num = '2';
break;
case 'i':
$num = '2';
break;
case '\\':
// Backslash escaping
if ( $p < $formatLength - 1 ) {
$s .= preg_quote( $format[++$p], '/' );
} else {
$s .= preg_quote( '\\', '/' );
}
break;
case '"':
// Quoted literal
if ( $p < $formatLength - 1 ) {
$endQuote = strpos( $format, '"', $p + 1 );
if ( $endQuote === false ) {
// No terminating quote, assume literal "
$s .= '"';
} else {
$s .= preg_quote( substr( $format, $p + 1, $endQuote - $p - 1 ), '/' );
$p = $endQuote;
}
} else {
// Quote at end of string, assume literal "
$s .= '"';
}
break;
default:
$s .= preg_quote( $format[$p], '/' );
}
if ( $num !== false ) {
$s .= '(' . $digitsRegexp . '{' . $num . '})';
}
}
$tzRegexp = self::regexpAlternateGroup( array_keys( $tzAbbrs ) );
// Hard-coded parentheses and space like in Parser::pstPass2
// Ignore some invisible Unicode characters that often sneak into copy-pasted timestamps (T245784)
// \uNNNN syntax can only be used from PHP 7.3
return '/' . $s . '[\\x{200E}\\x{200F}]? [\\x{200E}\\x{200F}]?\\(' . $tzRegexp . '\\)/u';
}
/**
* Get a function that parses timestamps generated using the given date format, based on the result
* of matching the regexp returned by getTimestampRegexp()
*
* @param string $contLangVariant Content language variant
* @param string $format Date format, as used by MediaWiki
* @param string[]|null $digits Localised digits from 0 to 9, e.g. `[ '0', '1', ..., '9' ]`
* @param string $localTimezone Local timezone IANA name, e.g. `America/New_York`
* @param array $tzAbbrs Map of localised timezone abbreviations to IANA abbreviations
* for the local timezone, e.g. [ 'EDT' => 'EDT', 'EST' => 'EST' ]
* @return callable Parser function
*/
private function getTimestampParser(
string $contLangVariant, string $format, ?array $digits, string $localTimezone, array $tzAbbrs
) : callable {
$untransformDigits = function ( string $text ) use ( $digits ) {
if ( !$digits ) {
return $text;
}
return preg_replace_callback(
'/[' . implode( '', $digits ) . ']/u',
function ( array $m ) use ( $digits ) {
return (string)array_search( $m[0], $digits );
},
$text
);
};
$formatLength = strlen( $format );
$matchingGroups = [];
for ( $p = 0; $p < $formatLength; $p++ ) {
$code = $format[$p];
if ( $code === 'x' && $p < $formatLength - 1 ) {
$code .= $format[++$p];
}
if ( $code === 'xk' && $p < $formatLength - 1 ) {
$code .= $format[++$p];
}
switch ( $code ) {
case 'xx':
break;
case 'xg':
case 'd':
case 'j':
case 'D':
case 'l':
case 'F':
case 'M':
case 'n':
case 'Y':
case 'xkY':
case 'G':
case 'H':
case 'i':
$matchingGroups[] = $code;
break;
case '\\':
// Backslash escaping
if ( $p < $formatLength - 1 ) {
$p++;
}
break;
case '"':
// Quoted literal
if ( $p < $formatLength - 1 ) {
$endQuote = strpos( $format, '"', $p + 1 );
if ( $endQuote !== false ) {
$p = $endQuote;
}
}
break;
default:
break;
}
}
return function ( array $match ) use (
$matchingGroups, $untransformDigits, $localTimezone, $tzAbbrs, $contLangVariant
) {
if ( is_array( $match[0] ) ) {
// Strip PREG_OFFSET_CAPTURE data
unset( $match['offset'] );
$match = array_map( function ( array $tuple ) {
return $tuple[0];
}, $match );
}
$year = 0;
$monthIdx = 0;
$day = 0;
$hour = 0;
$minute = 0;
foreach ( $matchingGroups as $i => $code ) {
$text = $match[$i + 1];
switch ( $code ) {
case 'xg':
$monthIdx = array_search(
$text,
$this->getMessages( $contLangVariant, Language::MONTH_GENITIVE_MESSAGES )
);
break;
case 'd':
case 'j':
$day = intval( $untransformDigits( $text ) );
break;
case 'D':
case 'l':
// Day of the week - unused
break;
case 'F':
$monthIdx = array_search(
$text,
$this->getMessages( $contLangVariant, Language::MONTH_MESSAGES )
);
break;
case 'M':
$monthIdx = array_search(
$text,
$this->getMessages( $contLangVariant, Language::MONTH_ABBREVIATED_MESSAGES )
);
break;
case 'n':
$monthIdx = intval( $untransformDigits( $text ) ) - 1;
break;
case 'Y':
$year = intval( $untransformDigits( $text ) );
break;
case 'xkY':
// Thai year
$year = intval( $untransformDigits( $text ) ) - 543;
break;
case 'G':
case 'H':
$hour = intval( $untransformDigits( $text ) );
break;
case 'i':
$minute = intval( $untransformDigits( $text ) );
break;
default:
// TODO throw NotImplementedException or whatever it's called
throw new MWException( 'Not implemented' );
}
}
// The last matching group is the timezone abbreviation
$tzAbbr = $tzAbbrs[ end( $match ) ];
// Most of the time, the timezone abbreviation is not necessary to parse the date, since we
// can assume all times are in the wiki's local timezone.
$date = new DateTime();
// setTimezone must be called before setDate/setTime
$date->setTimezone( new DateTimeZone( $localTimezone ) );
$date->setDate( $year, $monthIdx + 1, $day );
$date->setTime( $hour, $minute, 0 );
// But during the "fall back" at the end of DST, some times will happen twice.
// Since the timezone abbreviation disambiguates the DST/non-DST times, we can detect
// when PHP chose the wrong one, and then try the other one. It appears that PHP always
// uses the later (non-DST) hour, but that behavior isn't documented, so we account for both.
if ( $date->format( 'T' ) !== $tzAbbr ) {
$altDate = clone $date;
if ( $date->format( 'I' ) ) {
// Parsed time is DST, try non-DST by advancing one hour
$altDate->add( new DateInterval( 'PT1H' ) );
} else {
// Parsed time is non-DST, try DST by going back one hour
$altDate->sub( new DateInterval( 'PT1H' ) );
}
if ( $altDate->format( 'T' ) === $tzAbbr ) {
$date = $altDate;
$discussionToolsWarning = 'Timestamp has timezone abbreviation for the wrong time';
} else {
$discussionToolsWarning = 'Ambiguous time at DST switchover was parsed';
}
}
// Now set the timezone back to UTC for formatting
$date->setTimezone( new DateTimeZone( 'UTC' ) );
$date = DateTimeImmutable::createFromMutable( $date );
if ( isset( $discussionToolsWarning ) ) {
// @phan-suppress-next-line PhanUndeclaredProperty
$date->discussionToolsWarning = $discussionToolsWarning;
}
return $date;
};
}
/**
* Get a regexp that matches timestamps in the local date format, for each language variant.
*
* This calls getTimestampRegexp() with predefined data for the current wiki.
*
* @return string[] Regular expressions
*/
public function getLocalTimestampRegexps() : array {
$langConv = MediaWikiServices::getInstance()->getLanguageConverterFactory()
->getLanguageConverter( $this->language );
return array_map( function ( $contLangVariant ) {
return $this->getTimestampRegexp(
$contLangVariant,
$this->dateFormat[$contLangVariant],
'[' . implode( '', $this->digits[$contLangVariant] ) . ']',
$this->timezones[$contLangVariant]
);
}, $langConv->getVariants() );
}
/**
* Get a function that parses timestamps in the local date format, for each language variant,
* based on the result of matching the regexp returned by getLocalTimestampRegexp().
*
* This calls getTimestampParser() with predefined data for the current wiki.
*
* @return callable[] Parser functions
*/
private function getLocalTimestampParsers() : array {
$langConv = MediaWikiServices::getInstance()->getLanguageConverterFactory()
->getLanguageConverter( $this->language );
return array_map( function ( $contLangVariant ) {
return $this->getTimestampParser(
$contLangVariant,
$this->dateFormat[$contLangVariant],
$this->digits[$contLangVariant],
$this->localTimezone,
$this->timezones[$contLangVariant]
);
}, $langConv->getVariants() );
}
/**
* Given a link node (`<a>`), if it's a link to a user-related page, return their username.
*
* @param DOMElement $link
* @return string|null Username, or null
*/
private static function getUsernameFromLink( DOMElement $link ) {
$username = null;
$title = CommentUtils::getTitleFromUrl( $link->getAttribute( 'href' ) );
if ( !$title ) {
return null;
}
if ( $title->getNamespace() === NS_USER || $title->getNamespace() === NS_USER_TALK ) {
$username = $title->getText();
if ( strpos( $username, '/' ) !== false ) {
return null;
}
} elseif ( $title->isSpecial( 'Contributions' ) ) {
$parts = explode( '/', $title->getText(), 2 );
if ( !isset( $parts[1] ) ) {
return null;
}
// Normalize the username: users may link to their contributions with an unnormalized name
$userpage = Title::makeTitleSafe( NS_USER, $parts[1] );
if ( !$userpage ) {
return null;
}
$username = $userpage->getText();
}
if ( !$username ) {
return null;
}
if ( IP::isIPv6( $username ) ) {
// Bot-generated links "Preceding unsigned comment added by" have non-standard case
$username = strtoupper( $username );
}
return $username;
}
/**
* Find a user signature preceding a timestamp.
*
* The signature includes the timestamp node.
*
* A signature must contain at least one link to the user's userpage, discussion page or
* contributions (and may contain other links). The link may be nested in other elements.
*
* This function returns a two-element array. The first element is an array of sibling nodes
* comprising the signature, in reverse order (with $timestampNode or its parent node as the last
* element). The second element is the username (null for unsigned comments).
*
* @param DOMText $timestampNode
* @param DOMNode|null $until Node to stop searching at
* @return array [ nodes, username ]
*/
private function findSignature( DOMText $timestampNode, ?DOMNode $until = null ) : array {
$sigUsername = null;
$length = 0;
$lastLinkNode = $timestampNode;
CommentUtils::linearWalkBackwards(
$timestampNode,
function ( string $event, DOMNode $node ) use (
&$sigUsername, &$lastLinkNode, &$length,
$until, $timestampNode
) {
if ( $event === 'enter' && $node === $until ) {
return true;
}
if ( $length >= self::SIGNATURE_SCAN_LIMIT ) {
return true;
}
if ( CommentUtils::isBlockElement( $node ) ) {
// Don't allow reaching into preceding paragraphs
return true;
}
if ( $event === 'leave' && $node !== $timestampNode ) {
$length += $node instanceof DOMText ? mb_strlen( $node->textContent ) : 0;
}
// Find the closest link before timestamp that links to the user's user page.
//
// Support timestamps being linked to the diff introducing the comment:
// if the timestamp node is the only child of a link node, use the link node instead
//
// Handle links nested in formatting elements.
if ( $event === 'leave' && $node instanceof DOMElement && strtolower( $node->nodeName ) === 'a' ) {
$username = self::getUsernameFromLink( $node );
if ( $username ) {
// Accept the first link to the user namespace, then only accept links to that user
if ( $sigUsername === null ) {
$sigUsername = $username;
}
if ( $username === $sigUsername ) {
$lastLinkNode = $node;
}
}
// Keep looking if a node with links wasn't a link to a user page
// "Doc James (talk · contribs · email)"
}
}
);
$range = new ImmutableRange(
$lastLinkNode->parentNode,
CommentUtils::childIndexOf( $lastLinkNode ),
$timestampNode->parentNode,
CommentUtils::childIndexOf( $timestampNode ) + 1
);
// Expand the range so that it covers sibling nodes.
// This will include any wrapping formatting elements as part of the signature.
//
// Helpful accidental feature: users whose signature is not detected in full (due to
// text formatting) can just wrap it in a <span> to fix that.
// "Ten Pound Hammer • (What did I screw up now?)"
// "« Saper // dyskusja »"
//
// TODO Not sure if this is actually good, might be better to just use the range...
$sigNodes = array_reverse( CommentUtils::getCoveredSiblings( $range ) );
return [ $sigNodes, $sigUsername ];
}
/**
* Callback for TreeWalker that will skip over nodes where we don't want to detect
* comments (or section headings).
*
* @param DOMNode $node
* @return int Appropriate NodeFilter constant
*/
public static function acceptOnlyNodesAllowingComments( DOMNode $node ) {
// The table of contents has a heading that gets erroneously detected as a section
if ( $node instanceof DOMElement && $node->getAttribute( 'id' ) === 'toc' ) {
return NodeFilter::FILTER_REJECT;
}
// Don't detect comments within quotes (T275881)
if ( $node instanceof DOMElement && (
strtolower( $node->tagName ) === 'blockquote' ||
strtolower( $node->tagName ) === 'cite' ||
strtolower( $node->tagName ) === 'q'
) ) {
return NodeFilter::FILTER_REJECT;
}
// Don't detect comments within headings (but don't reject the headings themselves)
if ( ( $par = $node->parentNode ) instanceof DOMElement && preg_match( '/^h([1-6])$/i', $par->tagName ) ) {
return NodeFilter::FILTER_REJECT;
}
return NodeFilter::FILTER_ACCEPT;
}
/**
* Find a timestamps in a given text node
*
* @param DOMText $node
* @param string[] $timestampRegexps
* @return array|null Array with the following keys:
* - int 'offset' Length of extra text preceding the node that was used for matching
* - int 'parserIndex' Which of the regexps matched
* - array 'matchData' Regexp match data, which specifies the location of the match,
* and which can be parsed using getLocalTimestampParsers()
*/
public function findTimestamp( DOMText $node, array $timestampRegexps ) : ?array {
$nodeText = '';
$offset = 0;
while ( $node ) {
$nodeText = $node->nodeValue . $nodeText;
// In Parsoid HTML, entities are represented as a 'mw:Entity' node, rather than normal HTML
// entities. On Arabic Wikipedia, the "UTC" timezone name contains some non-breaking spaces,
// which apparently are often turned into &nbsp; entities by buggy editing tools. To handle
// this, we must piece together the text, so that our regexp can match those timestamps.
if (
( $previousSibling = $node->previousSibling ) &&
$previousSibling instanceof DOMElement &&
$previousSibling->getAttribute( 'typeof' ) === 'mw:Entity'
) {
$nodeText = $previousSibling->firstChild->nodeValue . $nodeText;
$offset += strlen( $previousSibling->firstChild->nodeValue );
// If the entity is preceded by more text, do this again
if (
$previousSibling->previousSibling &&
$previousSibling->previousSibling instanceof DOMText
) {
$offset += strlen( $previousSibling->previousSibling->nodeValue );
$node = $previousSibling->previousSibling;
} else {
$node = null;
}
} else {
$node = null;
}
}
foreach ( $timestampRegexps as $i => $timestampRegexp ) {
$matchData = null;
// Allows us to mimic match.index in #getComments
if ( preg_match( $timestampRegexp, $nodeText, $matchData, PREG_OFFSET_CAPTURE ) ) {
return [
'matchData' => $matchData,
'offset' => $offset,
'parserIndex' => $i,
];
}
}
return null;
}
/**
* Get all discussion comments (and headings) within a DOM subtree.
*
* This returns a flat list, use getThreads() to get a tree structure starting at section headings.
*
* For example, for a MediaWiki discussion like this (we're dealing with HTML DOM here,
* the wikitext syntax is just for illustration):
*
* == A ==
* B. ~~~~
* : C.
* : C. ~~~~
* :: D. ~~~~
* ::: E. ~~~~
* ::: F. ~~~~
* : G. ~~~~
* H. ~~~~
* : I. ~~~~
*
* This function would return a structure like:
*
* [
* HeadingItem( { level: 0, range: (h2: A) } ),
* CommentItem( { level: 1, range: (p: B) } ),
* CommentItem( { level: 2, range: (li: C, li: C) } ),
* CommentItem( { level: 3, range: (li: D) } ),
* CommentItem( { level: 4, range: (li: E) } ),
* CommentItem( { level: 4, range: (li: F) } ),
* CommentItem( { level: 2, range: (li: G) } ),
* CommentItem( { level: 1, range: (p: H) } ),
* CommentItem( { level: 2, range: (li: I) } )
* ]
*
* @return ThreadItem[] Thread items
*/
public function getThreadItems() : array {
if ( !$this->threadItems ) {
$this->buildThreads();
}
return $this->threadItems;
}
/**
* Same as getFlatThreadItems, but only returns the CommentItems
*
* @return CommentItem[] Comment items
*/
public function getCommentItems() : array {
if ( !$this->commentItems ) {
$this->buildThreads();
}
return $this->commentItems;
}
/**
* Find ThreadItems by their name
*
* This will usually return a single-element array, but it may return multiple comments if they're
* indistinguishable by name. In that case, use their IDs to disambiguate.
*
* @param string $name Name
* @return ThreadItem[] Thread items, empty array if not found
*/
public function findCommentsByName( string $name ) : array {
if ( !$this->threadItemsByName ) {
$this->buildThreads();
}
return $this->threadItemsByName[$name] ?? [];
}
/**
* Find a ThreadItem by its ID
*
* @param string $id ID
* @return ThreadItem|null Thread item, null if not found
*/
public function findCommentById( string $id ) : ?ThreadItem {
if ( !$this->threadItemsById ) {
$this->buildThreads();
}
return $this->threadItemsById[$id] ?? null;
}
/**
* @param DOMNode[] $sigNodes
* @param array $match
* @param DOMText $node
* @return ImmutableRange
*/
private function adjustSigRange( array $sigNodes, array $match, DOMText $node ) {
$firstSigNode = end( $sigNodes );
$lastSigNode = $sigNodes[0];
// TODO Document why this needs to be so complicated
$lastSigNodeOffset = $lastSigNode === $node ?
$match['matchData'][0][1] + strlen( $match['matchData'][0][0] ) - $match['offset'] :
CommentUtils::childIndexOf( $lastSigNode ) + 1;
$sigRange = new ImmutableRange(
$firstSigNode->parentNode,
CommentUtils::childIndexOf( $firstSigNode ),
$lastSigNode === $node ? $node : $lastSigNode->parentNode,
$lastSigNodeOffset
);
return $sigRange;
}
private function buildThreadItems() : void {
$timestampRegexps = $this->getLocalTimestampRegexps();
$commentItems = [];
$threadItems = [];
$dfParsers = $this->getLocalTimestampParsers();
// Placeholder heading in case there are comments in the 0th section
$range = new ImmutableRange( $this->rootNode, 0, $this->rootNode, 0 );
$fakeHeading = new HeadingItem( $range, 99, true );
$fakeHeading->setRootNode( $this->rootNode );
$curComment = $fakeHeading;
$curCommentEnd = $range->endContainer;
$treeWalker = new TreeWalker(
$this->rootNode,
NodeFilter::SHOW_ELEMENT | NodeFilter::SHOW_TEXT,
[ self::class, 'acceptOnlyNodesAllowingComments' ]
);
$lastSigNode = null;
while ( $node = $treeWalker->nextNode() ) {
if ( $node instanceof DOMElement && preg_match( '/^h([1-6])$/i', $node->tagName, $match ) ) {
$headingNodeAndOffset = CommentUtils::getHeadlineNodeAndOffset( $node );
$headingNode = $headingNodeAndOffset['node'];
$startOffset = $headingNodeAndOffset['offset'];
$range = new ImmutableRange(
$headingNode, $startOffset, $headingNode, $headingNode->childNodes->length
);
$curComment = new HeadingItem( $range, (int)( $match[ 1 ] ) );
$curComment->setRootNode( $this->rootNode );
$threadItems[] = $curComment;
$curCommentEnd = $node;
} elseif ( $node instanceof DOMText && ( $match = $this->findTimestamp( $node, $timestampRegexps ) ) ) {
$warnings = [];
$foundSignature = $this->findSignature( $node, $lastSigNode );
$author = $foundSignature[1];
$lastSigNode = $foundSignature[0][0];
if ( !$author ) {
// Ignore timestamps for which we couldn't find a signature. It's probably not a real
// comment, but just a false match due to a copypasted timestamp.
continue;
}
$sigRanges = [];
$sigRanges[] = $this->adjustSigRange( $foundSignature[0], $match, $node );
// Everything from the last comment up to here is the next comment
$startNode = $this->nextInterestingLeafNode( $curCommentEnd );
$endNode = $lastSigNode;
// Skip to the end of the "paragraph". This only looks at tag names and can be fooled by CSS, but
// avoiding that would be more difficult and slower.
//
// If this skips over another potential signature, also skip it in the main TreeWalker loop, to
// avoid generating multiple comments when there is more than one signature on a single "line".
// Often this is done when someone edits their comment later and wants to add a note about that.
// (Or when another person corrects a typo, or strikes out a comment, etc.) Multiple comments
// within one paragraph/list-item result in a confusing double "Reply" button, and we also have
// no way to indicate which one you're replying to (this might matter in the future for
// notifications or something).
CommentUtils::linearWalk(
$lastSigNode,
function ( string $event, DOMNode $n ) use (
&$endNode, &$sigRanges,
$treeWalker, $timestampRegexps, $node
) {
if ( CommentUtils::isBlockElement( $n ) ) {
// Stop when entering or leaving a block node
return true;
}
if (
$event === 'leave' &&
$n instanceof DOMText && $n !== $node &&
( $match2 = $this->findTimestamp( $n, $timestampRegexps ) )
) {
// If this skips over another potential signature, also skip it in the main TreeWalker loop
$treeWalker->currentNode = $n;
// …and add it as another signature to this comment (regardless of the author and timestamp)
$foundSignature2 = $this->findSignature( $n, $node );
if ( $foundSignature2[1] ) {
$sigRanges[] = $this->adjustSigRange( $foundSignature2[0], $match2, $n );
}
}
if ( $event === 'leave' ) {
// Take the last complete node which we skipped past
$endNode = $n;
}
}
);
$length = ( $endNode->nodeType === XML_TEXT_NODE ) ?
strlen( rtrim( $endNode->nodeValue, "\t\n\f\r " ) ) :
// PHP bug: childNodes can be null for comment nodes
// (it should always be a DOMNodeList, even if the node can't have children)
( $endNode->childNodes ? $endNode->childNodes->length : 0 );
$range = new ImmutableRange(
$startNode->parentNode,
CommentUtils::childIndexOf( $startNode ),
$endNode,
$length
);
$startLevel = CommentUtils::getIndentLevel( $startNode, $this->rootNode ) + 1;
$endLevel = CommentUtils::getIndentLevel( $node, $this->rootNode ) + 1;
if ( $startLevel !== $endLevel ) {
$warnings[] = 'Comment starts and ends with different indentation';
}
// Should this use the indent level of $startNode or $node?
$level = min( $startLevel, $endLevel );
$dateTime = $dfParsers[ $match['parserIndex'] ]( $match['matchData'] );
if ( isset( $dateTime->discussionToolsWarning ) ) {
$warnings[] = $dateTime->discussionToolsWarning;
}
// ISO 8601 date. Almost DateTimeInterface::RFC3339_EXTENDED, but ending with 'Z' instead
// of '+00:00', like Date#toISOString in JavaScript.
$dateTimeStr = $dateTime->format( 'Y-m-d\TH:i:s.v\Z' );
$curComment = new CommentItem(
$level,
$range,
$sigRanges,
$dateTimeStr,
$author
);
$curComment->setRootNode( $this->rootNode );
if ( $warnings ) {
$curComment->addWarnings( $warnings );
}
$commentItems[] = $curComment;
$threadItems[] = $curComment;
$curCommentEnd = $curComment->getRange()->endContainer;
}
}
// Insert the fake placeholder heading if there are any comments in the 0th section
// (before the first real heading)
if ( count( $threadItems ) && !( $threadItems[ 0 ] instanceof HeadingItem ) ) {
array_unshift( $threadItems, $fakeHeading );
}
$this->commentItems = $commentItems;
$this->threadItems = $threadItems;
}
/**
* Group discussion comments into threads and associate replies to original messages.
*
* Each thread must begin with a heading. Original messages in the thread are treated as replies to
* its heading. Other replies are associated based on the order and indentation level.
*
* Note that the objects in `comments` are extended in-place with the additional data.
*
* For example, for a MediaWiki discussion like this (we're dealing with HTML DOM here,
* the wikitext syntax is just for illustration):
*
* == A ==
* B. ~~~~
* : C.
* : C. ~~~~
* :: D. ~~~~
* ::: E. ~~~~
* ::: F. ~~~~
* : G. ~~~~
* H. ~~~~
* : I. ~~~~
*
* This function would return a structure like:
*
* [
* HeadingItem( { level: 0, range: (h2: A), replies: [
* CommentItem( { level: 1, range: (p: B), replies: [
* CommentItem( { level: 2, range: (li: C, li: C), replies: [
* CommentItem( { level: 3, range: (li: D), replies: [
* CommentItem( { level: 4, range: (li: E), replies: [] },
* CommentItem( { level: 4, range: (li: F), replies: [] },
* ] },
* ] },
* CommentItem( { level: 2, range: (li: G), replies: [] },
* ] },
* CommentItem( { level: 1, range: (p: H), replies: [
* CommentItem( { level: 2, range: (li: I), replies: [] },
* ] },
* ] } )
* ]
*
* @return HeadingItem[] Tree structure of comments, top-level items are the headings.
*/
public function getThreads() : array {
if ( !$this->threads ) {
$this->buildThreads();
}
return $this->threads;
}
/**
* Truncate user generated parts of IDs so full ID always fits within a database field of length 255
*
* @param string $text Text
* @return string Truncated text
*/
private function truncateForId( string $text ) : string {
return $this->language->truncateForDatabase( $text, 80, '' );
}
/**
* Given a thread item, return an identifier for it that is unique within the page.
*
* @param ThreadItem $threadItem
* @param bool $noDedupe Internal. Don't attempt to de-duplicate
* @return string
*/
private function computeId( ThreadItem $threadItem, bool $noDedupe = false ) : string {
$id = null;
if ( $threadItem instanceof HeadingItem && $threadItem->isPlaceholderHeading() ) {
// The range points to the root note, using it like below results in silly values
$id = 'h-';
} elseif ( $threadItem instanceof HeadingItem ) {
$headline = CommentUtils::getHeadlineNodeAndOffset( $threadItem->getRange()->startContainer )['node'];
$id = 'h-' . $this->truncateForId( $headline->getAttribute( 'id' ) ?? '' );
} elseif ( $threadItem instanceof CommentItem ) {
$id = 'c-' . $this->truncateForId( str_replace( ' ', '_', $threadItem->getAuthor() ) ) .
'-' . $threadItem->getTimestamp();
} else {
throw new MWException( 'Unknown ThreadItem type' );
}
// If there would be multiple comments with the same ID (i.e. the user left multiple comments
// in one edit, or within a minute), add the parent ID to disambiguate them.
$threadItemParent = $threadItem->getParent();
if ( $threadItemParent instanceof HeadingItem && !$threadItemParent->isPlaceholderHeading() ) {
$headline = CommentUtils::getHeadlineNodeAndOffset( $threadItemParent->getRange()->startContainer )['node'];
$id .= '-' . $this->truncateForId( $headline->getAttribute( 'id' ) ?? '' );
} elseif ( $threadItemParent instanceof CommentItem ) {
$id .= '-' . $this->truncateForId( str_replace( ' ', '_', $threadItemParent->getAuthor() ) ) .
'-' . $threadItemParent->getTimestamp();
}
if ( $threadItem instanceof HeadingItem ) {
// To avoid old threads re-appearing on popular pages when someone uses a vague title
// (e.g. dozens of threads titled "question" on [[Wikipedia:Help desk]]: https://w.wiki/fbN),
// include the oldest timestamp in the thread (i.e. date the thread was started) in the
// heading ID.
$oldestComment = $this->getThreadStartComment( $threadItem );
if ( $oldestComment ) {
$id .= '-' . $oldestComment->getTimestamp();
}
}
if ( !$noDedupe && isset( $this->threadItemsById[$id] ) ) {
// Well, that's tough
$threadItem->addWarning( 'Duplicate comment ID' );
// Finally, disambiguate by adding sequential numbers, to allow replying to both comments
$number = 1;
while ( isset( $this->threadItemsById["$id-$number"] ) ) {
$number++;
}
$id = "$id-$number";
}
return $id;
}
/**
* Given a thread item, return an identifier for it like computeId(), generated according to an
* older algorithm, so that we can still match IDs from cached data.
*
* @param ThreadItem $threadItem
* @return string|null
*/
private function computeLegacyId( ThreadItem $threadItem ) : ?string {
$id = null;
if ( $threadItem instanceof HeadingItem && $threadItem->isPlaceholderHeading() ) {
// The range points to the root note, using it like below results in silly values
$id = 'h|';
} elseif ( $threadItem instanceof HeadingItem ) {
$headline = CommentUtils::getHeadlineNodeAndOffset( $threadItem->getRange()->startContainer )['node'];
$id = 'h|' . $this->truncateForId( $headline->getAttribute( 'id' ) ?? '' );
} elseif ( $threadItem instanceof CommentItem ) {
$id = 'c|' . $this->truncateForId( $threadItem->getAuthor() ) .
'|' . $threadItem->getTimestamp();
} else {
throw new MWException( 'Unknown ThreadItem type' );
}
// If there would be multiple comments with the same ID (i.e. the user left multiple comments
// in one edit, or within a minute), add the parent ID to disambiguate them.
$threadItemParent = $threadItem->getParent();
if ( $threadItemParent instanceof HeadingItem && !$threadItemParent->isPlaceholderHeading() ) {
$headline = CommentUtils::getHeadlineNodeAndOffset( $threadItemParent->getRange()->startContainer )['node'];
$id .= '|' . $this->truncateForId( $headline->getAttribute( 'id' ) ?? '' );
} elseif ( $threadItemParent instanceof CommentItem ) {
$id .= '|' . $this->truncateForId( $threadItemParent->getAuthor() ) .
'|' . $threadItemParent->getTimestamp();
}
if ( $threadItem instanceof HeadingItem ) {
// To avoid old threads re-appearing on popular pages when someone uses a vague title
// (e.g. dozens of threads titled "question" on [[Wikipedia:Help desk]]: https://w.wiki/fbN),
// include the oldest timestamp in the thread (i.e. date the thread was started) in the
// heading ID.
$oldestComment = $this->getThreadStartComment( $threadItem );
if ( $oldestComment ) {
$id .= '|' . $oldestComment->getTimestamp();
}
}
// Legacy IDs are only required if different to the current ID
if ( $id === $this->computeId( $threadItem, true ) ) {
return null;
}
if ( isset( $this->threadItemsById[$id] ) ) {
// Well, that's tough
$threadItem->addWarning( 'Duplicate comment legacy ID' );
// Finally, disambiguate by adding sequential numbers, to allow replying to both comments
$number = 1;
while ( isset( $this->threadItemsById["$id|$number"] ) ) {
$number++;
}
$id = "$id|$number";
}
return $id;
}
/**
* Given a thread item, return an identifier for it that is consistent across all pages and
* revisions where this comment might appear.
*
* Multiple comments on a page can have the same name; use ID to distinguish them.
*
* @param ThreadItem $threadItem
* @return string
*/
private function computeName( ThreadItem $threadItem ) : string {
$name = null;
if ( $threadItem instanceof HeadingItem ) {
$name = 'h-';
$mainComment = $this->getThreadStartComment( $threadItem );
} elseif ( $threadItem instanceof CommentItem ) {
$name = 'c-';
$mainComment = $threadItem;
} else {
throw new MWException( 'Unknown ThreadItem type' );
}
if ( $mainComment ) {
$name .= $this->truncateForId( str_replace( ' ', '_', $mainComment->getAuthor() ) ) .
'-' . $mainComment->getTimestamp();
}
return $name;
}
private function buildThreads() : void {
if ( !$this->threadItems ) {
$this->buildThreadItems();
}
$threads = [];
$replies = [];
$this->threadItemsById = [];
$this->threadItemsByName = [];
foreach ( $this->threadItems as $threadItem ) {
if ( count( $replies ) < $threadItem->getLevel() ) {
// Someone skipped an indentation level (or several). Pretend that the previous reply
// covers multiple indentation levels, so that following comments get connected to it.
$threadItem->addWarning( 'Comment skips indentation level' );
while ( count( $replies ) < $threadItem->getLevel() ) {
$replies[] = end( $replies );
}
}
if ( $threadItem instanceof HeadingItem ) {
// New root (thread)
$threads[] = $threadItem;
// Attach as a sub-thread to preceding higher-level heading.
// Any replies will appear in the tree twice, under the main-thread and the sub-thread.
$maybeParent = count( $threads ) > 1 ? $threads[ count( $threads ) - 2 ] : null;
while ( $maybeParent && $maybeParent->getHeadingLevel() >= $threadItem->getHeadingLevel() ) {
$maybeParent = $maybeParent->getParent();
}
if ( $maybeParent ) {
$threadItem->setParent( $maybeParent );
$maybeParent->addReply( $threadItem );
}
} elseif ( isset( $replies[ $threadItem->getLevel() - 1 ] ) ) {
// Add as a reply to the closest less-nested comment
$threadItem->setParent( $replies[ $threadItem->getLevel() - 1 ] );
$threadItem->getParent()->addReply( $threadItem );
} else {
$threadItem->addWarning( 'Comment could not be connected to a thread' );
}
$replies[ $threadItem->getLevel() ] = $threadItem;
// Cut off more deeply nested replies
array_splice( $replies, $threadItem->getLevel() + 1 );
}
$this->threads = $threads;
foreach ( $this->threadItems as $threadItem ) {
$name = $this->computeName( $threadItem );
$threadItem->setName( $name );
$this->threadItemsByName[$name][] = $threadItem;
// Set the IDs used to refer to comments and headings.
// This has to be a separate pass because we don't have the list of replies before
// this point.
$id = $this->computeId( $threadItem );
$threadItem->setId( $id );
$this->threadItemsById[$id] = $threadItem;
$legacyId = $this->computeLegacyId( $threadItem );
$threadItem->setLegacyId( $legacyId );
if ( $legacyId ) {
$this->threadItemsById[$legacyId] = $threadItem;
}
}
}
/**
* @param ThreadItem $threadItem
* @return CommentItem|null
*/
private function getThreadStartComment( ThreadItem $threadItem ) {
$oldest = null;
if ( $threadItem instanceof CommentItem ) {
$oldest = $threadItem;
}
// Check all replies. This can't just use the first comment because threads are often summarized
// at the top when the discussion is closed.
foreach ( $threadItem->getReplies() as $comment ) {
// Don't include sub-threads to avoid changing the ID when threads are "merged".
if ( $comment instanceof CommentItem ) {
$oldestInReplies = $this->getThreadStartComment( $comment );
if ( !$oldest || $oldestInReplies->getTimestamp() < $oldest->getTimestamp() ) {
$oldest = $oldestInReplies;
}
}
}
return $oldest;
}
}