mirror of
https://gerrit.wikimedia.org/r/mediawiki/extensions/AbuseFilter.git
synced 2024-12-01 00:56:26 +00:00
280 lines
8.5 KiB
PHP
280 lines
8.5 KiB
PHP
<?php
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/**
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* AbuseFilterCachingParser is the version of AbuseFilterParser which parses
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* the code into an abstract syntax tree before evaluating it, and caches that
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* tree.
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*
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* It currently inherits AbuseFilterParser in order to avoid code duplication.
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* In future, this code will replace current AbuseFilterParser entirely.
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*/
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class AbuseFilterCachingParser extends AbuseFilterParser {
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/**
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* Return the generated version of the parser for cache invalidation
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* purposes. Automatically tracks list of all functions and invalidates the
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* cache if it is changed.
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* @return string
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*/
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public static function getCacheVersion() {
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static $version = null;
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if ( $version !== null ) {
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return $version;
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}
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$versionKey = [
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AFPTreeParser::CACHE_VERSION,
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AbuseFilterTokenizer::CACHE_VERSION,
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array_keys( AbuseFilterParser::$mFunctions ),
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array_keys( AbuseFilterParser::$mKeywords ),
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];
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$version = hash( 'sha256', serialize( $versionKey ) );
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return $version;
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}
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public function resetState() {
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$this->mVars = new AbuseFilterVariableHolder;
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$this->mCur = new AFPToken();
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}
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public function intEval( $code ) {
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static $cache = null;
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if ( !$cache ) {
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$cache = ObjectCache::getLocalServerInstance( 'hash' );
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}
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$tree = $cache->getWithSetCallback(
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$cache->makeGlobalKey(
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__CLASS__,
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self::getCacheVersion(),
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hash( 'sha256', $code )
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),
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$cache::TTL_DAY,
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function () use ( $code ) {
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$parser = new AFPTreeParser();
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return $parser->parse( $code ) ?: false;
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}
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);
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return $tree
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? $this->evalNode( $tree )
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: new AFPData( AFPData::DNULL, null );
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}
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/**
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* Evaluate the value of the specified AST node.
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*
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* @param AFPTreeNode $node The node to evaluate.
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* @return AFPData
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* @throws AFPException
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* @throws AFPUserVisibleException
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* @throws MWException
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*/
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public function evalNode( AFPTreeNode $node ) {
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// A lot of AbuseFilterParser features rely on $this->mCur->pos or
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// $this->mPos for error reporting.
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// FIXME: this is a hack which needs to be removed when the parsers are
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// merged.
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$this->mPos = $node->position;
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$this->mCur->pos = $node->position;
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switch ( $node->type ) {
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case AFPTreeNode::ATOM:
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$tok = $node->children;
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switch ( $tok->type ) {
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case AFPToken::TID:
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return $this->getVarValue( strtolower( $tok->value ) );
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case AFPToken::TSTRING:
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return new AFPData( AFPData::DSTRING, $tok->value );
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case AFPToken::TFLOAT:
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return new AFPData( AFPData::DFLOAT, $tok->value );
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case AFPToken::TINT:
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return new AFPData( AFPData::DINT, $tok->value );
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/** @noinspection PhpMissingBreakStatementInspection */
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case AFPToken::TKEYWORD:
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switch ( $tok->value ) {
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case "true":
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return new AFPData( AFPData::DBOOL, true );
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case "false":
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return new AFPData( AFPData::DBOOL, false );
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case "null":
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return new AFPData();
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}
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// Fallthrough intended
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default:
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throw new AFPException( "Unknown token provided in the ATOM node" );
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}
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case AFPTreeNode::LIST_DEFINITION:
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$items = array_map( [ $this, 'evalNode' ], $node->children );
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return new AFPData( AFPData::DLIST, $items );
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case AFPTreeNode::FUNCTION_CALL:
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$functionName = $node->children[0];
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$args = array_slice( $node->children, 1 );
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$func = self::$mFunctions[$functionName];
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$dataArgs = array_map( [ $this, 'evalNode' ], $args );
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/** @noinspection PhpToStringImplementationInspection */
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$funcHash = md5( $func . serialize( $dataArgs ) );
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if ( isset( self::$funcCache[$funcHash] ) &&
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!in_array( $func, self::$ActiveFunctions )
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) {
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$result = self::$funcCache[$funcHash];
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} else {
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AbuseFilter::triggerLimiter();
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$result = self::$funcCache[$funcHash] = $this->$func( $dataArgs );
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}
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if ( count( self::$funcCache ) > 1000 ) {
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self::$funcCache = [];
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}
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return $result;
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case AFPTreeNode::LIST_INDEX:
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list( $list, $offset ) = $node->children;
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$list = $this->evalNode( $list );
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if ( $list->type != AFPData::DLIST ) {
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throw new AFPUserVisibleException( 'notlist', $node->position, [] );
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}
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$offset = $this->evalNode( $offset )->toInt();
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$list = $list->toList();
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if ( count( $list ) <= $offset ) {
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throw new AFPUserVisibleException( 'outofbounds', $node->position,
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[ $offset, count( $list ) ] );
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}
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return $list[$offset];
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case AFPTreeNode::UNARY:
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list( $operation, $argument ) = $node->children;
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$argument = $this->evalNode( $argument );
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if ( $operation == '-' ) {
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return AFPData::unaryMinus( $argument );
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}
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return $argument;
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case AFPTreeNode::KEYWORD_OPERATOR:
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list( $keyword, $leftOperand, $rightOperand ) = $node->children;
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$func = self::$mKeywords[$keyword];
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$leftOperand = $this->evalNode( $leftOperand );
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$rightOperand = $this->evalNode( $rightOperand );
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AbuseFilter::triggerLimiter();
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$result = AFPData::$func( $leftOperand, $rightOperand, $node->position );
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return $result;
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case AFPTreeNode::BOOL_INVERT:
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list( $argument ) = $node->children;
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$argument = $this->evalNode( $argument );
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return AFPData::boolInvert( $argument );
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case AFPTreeNode::POW:
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list( $base, $exponent ) = $node->children;
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$base = $this->evalNode( $base );
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$exponent = $this->evalNode( $exponent );
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return AFPData::pow( $base, $exponent );
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case AFPTreeNode::MUL_REL:
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list( $op, $leftOperand, $rightOperand ) = $node->children;
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$leftOperand = $this->evalNode( $leftOperand );
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$rightOperand = $this->evalNode( $rightOperand );
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return AFPData::mulRel( $leftOperand, $rightOperand, $op, /* FIXME */
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0 );
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case AFPTreeNode::SUM_REL:
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list( $op, $leftOperand, $rightOperand ) = $node->children;
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$leftOperand = $this->evalNode( $leftOperand );
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$rightOperand = $this->evalNode( $rightOperand );
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switch ( $op ) {
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case '+':
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return AFPData::sum( $leftOperand, $rightOperand );
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case '-':
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return AFPData::sub( $leftOperand, $rightOperand );
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default:
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throw new AFPException( "Unknown sum-related operator: {$op}" );
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}
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case AFPTreeNode::COMPARE:
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list( $op, $leftOperand, $rightOperand ) = $node->children;
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$leftOperand = $this->evalNode( $leftOperand );
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$rightOperand = $this->evalNode( $rightOperand );
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AbuseFilter::triggerLimiter();
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return AFPData::compareOp( $leftOperand, $rightOperand, $op );
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case AFPTreeNode::LOGIC:
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list( $op, $leftOperand, $rightOperand ) = $node->children;
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$leftOperand = $this->evalNode( $leftOperand );
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$value = $leftOperand->toBool();
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// Short-circuit.
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if ( ( !$value && $op == '&' ) || ( $value && $op == '|' ) ) {
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return $leftOperand;
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}
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$rightOperand = $this->evalNode( $rightOperand );
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return AFPData::boolOp( $leftOperand, $rightOperand, $op );
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case AFPTreeNode::CONDITIONAL:
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list( $condition, $valueIfTrue, $valueIfFalse ) = $node->children;
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$condition = $this->evalNode( $condition );
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if ( $condition->toBool() ) {
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return $this->evalNode( $valueIfTrue );
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} else {
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return $this->evalNode( $valueIfFalse );
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}
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case AFPTreeNode::ASSIGNMENT:
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list( $varName, $value ) = $node->children;
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$value = $this->evalNode( $value );
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$this->setUserVariable( $varName, $value );
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return $value;
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case AFPTreeNode::INDEX_ASSIGNMENT:
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list( $varName, $offset, $value ) = $node->children;
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$list = $this->mVars->getVar( $varName );
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if ( $list->type != AFPData::DLIST ) {
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throw new AFPUserVisibleException( 'notlist', $node->position, [] );
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}
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$offset = $this->evalNode( $offset )->toInt();
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$list = $list->toList();
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if ( count( $list ) <= $offset ) {
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throw new AFPUserVisibleException( 'outofbounds', $node->position,
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[ $offset, count( $list ) ] );
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}
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$list[$offset] = $this->evalNode( $value );
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$this->setUserVariable( $varName, new AFPData( AFPData::DLIST, $list ) );
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return $value;
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case AFPTreeNode::LIST_APPEND:
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list( $varName, $value ) = $node->children;
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$list = $this->mVars->getVar( $varName );
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if ( $list->type != AFPData::DLIST ) {
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throw new AFPUserVisibleException( 'notlist', $node->position, [] );
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}
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$list = $list->toList();
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$list[] = $this->evalNode( $value );
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$this->setUserVariable( $varName, new AFPData( AFPData::DLIST, $list ) );
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return $value;
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case AFPTreeNode::SEMICOLON:
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$lastValue = null;
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foreach ( $node->children as $statement ) {
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$lastValue = $this->evalNode( $statement );
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}
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return $lastValue;
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default:
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throw new AFPException( "Unknown node type passed: {$node->type}" );
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}
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}
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}
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