mediawiki-extensions-AbuseF.../includes/parser/AbuseFilterCachingParser.php
Daimona Eaytoy cea1b0aec3 Compact some other comments
Remove unnecessary ones, make clear what the cryptic ones mean, and
inline them when possible.

Change-Id: I384859871a66ced8cb0d81260c06c5a5b278866f
2018-07-17 17:17:44 +02:00

286 lines
8.7 KiB
PHP

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