mirror of
https://gerrit.wikimedia.org/r/mediawiki/extensions/AbuseFilter.git
synced 2024-09-25 11:16:25 +00:00
612 lines
14 KiB
PHP
612 lines
14 KiB
PHP
<?php
|
|
|
|
/**
|
|
* A version of the abuse filter parser that separates parsing the filter and
|
|
* evaluating it into different passes, allowing the parse tree to be cached.
|
|
*
|
|
* @file
|
|
*/
|
|
|
|
/**
|
|
* A parser that transforms the text of the filter into a parse tree.
|
|
*/
|
|
class AFPTreeParser {
|
|
// The tokenized representation of the filter parsed.
|
|
public $mTokens;
|
|
|
|
// Current token handled by the parser and its position.
|
|
public $mCur, $mPos;
|
|
|
|
const CACHE_VERSION = 2;
|
|
|
|
/**
|
|
* Create a new instance
|
|
*/
|
|
public function __construct() {
|
|
$this->resetState();
|
|
}
|
|
|
|
public function resetState() {
|
|
$this->mTokens = [];
|
|
$this->mPos = 0;
|
|
}
|
|
|
|
/**
|
|
* Advances the parser to the next token in the filter code.
|
|
*/
|
|
protected function move() {
|
|
list( $this->mCur, $this->mPos ) = $this->mTokens[$this->mPos];
|
|
}
|
|
|
|
/**
|
|
* getState() function allows parser state to be rollbacked to several tokens
|
|
* back.
|
|
*
|
|
* @return AFPParserState
|
|
*/
|
|
protected function getState() {
|
|
return new AFPParserState( $this->mCur, $this->mPos );
|
|
}
|
|
|
|
/**
|
|
* setState() function allows parser state to be rollbacked to several tokens
|
|
* back.
|
|
*
|
|
* @param AFPParserState $state
|
|
*/
|
|
protected function setState( AFPParserState $state ) {
|
|
$this->mCur = $state->token;
|
|
$this->mPos = $state->pos;
|
|
}
|
|
|
|
/**
|
|
* Parse the supplied filter source code into a tree.
|
|
*
|
|
* @param string $code
|
|
* @throws AFPUserVisibleException
|
|
* @return AFPTreeNode|null
|
|
*/
|
|
public function parse( $code ) {
|
|
$this->mTokens = AbuseFilterTokenizer::tokenize( $code );
|
|
$this->mPos = 0;
|
|
|
|
return $this->doLevelEntry();
|
|
}
|
|
|
|
/* Levels */
|
|
|
|
/**
|
|
* Handles unexpected characters after the expression.
|
|
* @return AFPTreeNode|null
|
|
* @throws AFPUserVisibleException
|
|
*/
|
|
protected function doLevelEntry() {
|
|
$result = $this->doLevelSemicolon();
|
|
|
|
if ( $this->mCur->type != AFPToken::TNONE ) {
|
|
throw new AFPUserVisibleException(
|
|
'unexpectedatend',
|
|
$this->mPos, [ $this->mCur->type ]
|
|
);
|
|
}
|
|
|
|
return $result;
|
|
}
|
|
|
|
/**
|
|
* Handles the semicolon operator.
|
|
*
|
|
* @return AFPTreeNode|null
|
|
*/
|
|
protected function doLevelSemicolon() {
|
|
$statements = [];
|
|
|
|
do {
|
|
$this->move();
|
|
$position = $this->mPos;
|
|
|
|
if ( $this->mCur->type == AFPToken::TNONE ) {
|
|
break;
|
|
}
|
|
|
|
// Allow empty statements.
|
|
if ( $this->mCur->type == AFPToken::TSTATEMENTSEPARATOR ) {
|
|
continue;
|
|
}
|
|
|
|
$statements[] = $this->doLevelSet();
|
|
$position = $this->mPos;
|
|
} while ( $this->mCur->type == AFPToken::TSTATEMENTSEPARATOR );
|
|
|
|
// Flatten the tree if possible.
|
|
if ( count( $statements ) == 0 ) {
|
|
return null;
|
|
} elseif ( count( $statements ) == 1 ) {
|
|
return $statements[0];
|
|
} else {
|
|
return new AFPTreeNode( AFPTreeNode::SEMICOLON, $statements, $position );
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Handles variable assignment.
|
|
*
|
|
* @return AFPTreeNode
|
|
* @throws AFPUserVisibleException
|
|
*/
|
|
protected function doLevelSet() {
|
|
if ( $this->mCur->type == AFPToken::TID ) {
|
|
$varname = $this->mCur->value;
|
|
|
|
// Speculatively parse the assignment statement assuming it can
|
|
// potentially be an assignment, but roll back if it isn't.
|
|
$initialState = $this->getState();
|
|
$this->move();
|
|
|
|
if ( $this->mCur->type == AFPToken::TOP && $this->mCur->value == ':=' ) {
|
|
$position = $this->mPos;
|
|
$this->move();
|
|
$value = $this->doLevelSet();
|
|
|
|
return new AFPTreeNode( AFPTreeNode::ASSIGNMENT, [ $varname, $value ], $position );
|
|
}
|
|
|
|
if ( $this->mCur->type == AFPToken::TSQUAREBRACKET && $this->mCur->value == '[' ) {
|
|
$this->move();
|
|
|
|
if ( $this->mCur->type == AFPToken::TSQUAREBRACKET && $this->mCur->value == ']' ) {
|
|
$index = 'append';
|
|
} else {
|
|
// Parse index offset.
|
|
$this->setState( $initialState );
|
|
$this->move();
|
|
$index = $this->doLevelSemicolon();
|
|
if ( !( $this->mCur->type == AFPToken::TSQUAREBRACKET && $this->mCur->value == ']' ) ) {
|
|
throw new AFPUserVisibleException( 'expectednotfound', $this->mPos,
|
|
[ ']', $this->mCur->type, $this->mCur->value ] );
|
|
}
|
|
}
|
|
|
|
$this->move();
|
|
if ( $this->mCur->type == AFPToken::TOP && $this->mCur->value == ':=' ) {
|
|
$position = $this->mPos;
|
|
$this->move();
|
|
$value = $this->doLevelSet();
|
|
if ( $index === 'append' ) {
|
|
return new AFPTreeNode(
|
|
AFPTreeNode::LIST_APPEND, [ $varname, $value ], $position );
|
|
} else {
|
|
return new AFPTreeNode(
|
|
AFPTreeNode::INDEX_ASSIGNMENT,
|
|
[ $varname, $index, $value ],
|
|
$position
|
|
);
|
|
}
|
|
}
|
|
}
|
|
|
|
// If we reached this point, we did not find an assignment. Roll back
|
|
// and assume this was just a literal.
|
|
$this->setState( $initialState );
|
|
}
|
|
|
|
return $this->doLevelConditions();
|
|
}
|
|
|
|
/**
|
|
* Handles ternary operator and if-then-else-end.
|
|
*
|
|
* @return AFPTreeNode
|
|
* @throws AFPUserVisibleException
|
|
*/
|
|
protected function doLevelConditions() {
|
|
if ( $this->mCur->type == AFPToken::TKEYWORD && $this->mCur->value == 'if' ) {
|
|
$position = $this->mPos;
|
|
$this->move();
|
|
$condition = $this->doLevelBoolOps();
|
|
|
|
if ( !( $this->mCur->type == AFPToken::TKEYWORD && $this->mCur->value == 'then' ) ) {
|
|
throw new AFPUserVisibleException( 'expectednotfound',
|
|
$this->mPos,
|
|
[
|
|
'then',
|
|
$this->mCur->type,
|
|
$this->mCur->value
|
|
]
|
|
);
|
|
}
|
|
$this->move();
|
|
|
|
$valueIfTrue = $this->doLevelConditions();
|
|
|
|
if ( !( $this->mCur->type == AFPToken::TKEYWORD && $this->mCur->value == 'else' ) ) {
|
|
throw new AFPUserVisibleException( 'expectednotfound',
|
|
$this->mPos,
|
|
[
|
|
'else',
|
|
$this->mCur->type,
|
|
$this->mCur->value
|
|
]
|
|
);
|
|
}
|
|
$this->move();
|
|
|
|
$valueIfFalse = $this->doLevelConditions();
|
|
|
|
if ( !( $this->mCur->type == AFPToken::TKEYWORD && $this->mCur->value == 'end' ) ) {
|
|
throw new AFPUserVisibleException( 'expectednotfound',
|
|
$this->mPos,
|
|
[
|
|
'end',
|
|
$this->mCur->type,
|
|
$this->mCur->value
|
|
]
|
|
);
|
|
}
|
|
$this->move();
|
|
|
|
return new AFPTreeNode(
|
|
AFPTreeNode::CONDITIONAL,
|
|
[ $condition, $valueIfTrue, $valueIfFalse ],
|
|
$position
|
|
);
|
|
}
|
|
|
|
$condition = $this->doLevelBoolOps();
|
|
if ( $this->mCur->type == AFPToken::TOP && $this->mCur->value == '?' ) {
|
|
$position = $this->mPos;
|
|
$this->move();
|
|
|
|
$valueIfTrue = $this->doLevelConditions();
|
|
if ( !( $this->mCur->type == AFPToken::TOP && $this->mCur->value == ':' ) ) {
|
|
throw new AFPUserVisibleException( 'expectednotfound',
|
|
$this->mPos,
|
|
[
|
|
':',
|
|
$this->mCur->type,
|
|
$this->mCur->value
|
|
]
|
|
);
|
|
}
|
|
$this->move();
|
|
|
|
$valueIfFalse = $this->doLevelConditions();
|
|
return new AFPTreeNode(
|
|
AFPTreeNode::CONDITIONAL,
|
|
[ $condition, $valueIfTrue, $valueIfFalse ],
|
|
$position
|
|
);
|
|
}
|
|
|
|
return $condition;
|
|
}
|
|
|
|
/**
|
|
* Handles logic operators.
|
|
*
|
|
* @return AFPTreeNode
|
|
*/
|
|
protected function doLevelBoolOps() {
|
|
$leftOperand = $this->doLevelCompares();
|
|
$ops = [ '&', '|', '^' ];
|
|
while ( $this->mCur->type == AFPToken::TOP && in_array( $this->mCur->value, $ops ) ) {
|
|
$op = $this->mCur->value;
|
|
$position = $this->mPos;
|
|
$this->move();
|
|
|
|
$rightOperand = $this->doLevelCompares();
|
|
|
|
$leftOperand = new AFPTreeNode(
|
|
AFPTreeNode::LOGIC,
|
|
[ $op, $leftOperand, $rightOperand ],
|
|
$position
|
|
);
|
|
}
|
|
return $leftOperand;
|
|
}
|
|
|
|
/**
|
|
* Handles comparison operators.
|
|
*
|
|
* @return AFPTreeNode
|
|
*/
|
|
protected function doLevelCompares() {
|
|
$leftOperand = $this->doLevelSumRels();
|
|
$ops = [ '==', '===', '!=', '!==', '<', '>', '<=', '>=', '=' ];
|
|
while ( $this->mCur->type == AFPToken::TOP && in_array( $this->mCur->value, $ops ) ) {
|
|
$op = $this->mCur->value;
|
|
$position = $this->mPos;
|
|
$this->move();
|
|
$rightOperand = $this->doLevelSumRels();
|
|
$leftOperand = new AFPTreeNode(
|
|
AFPTreeNode::COMPARE,
|
|
[ $op, $leftOperand, $rightOperand ],
|
|
$position
|
|
);
|
|
}
|
|
return $leftOperand;
|
|
}
|
|
|
|
/**
|
|
* Handle addition and subtraction.
|
|
*
|
|
* @return AFPTreeNode
|
|
*/
|
|
protected function doLevelSumRels() {
|
|
$leftOperand = $this->doLevelMulRels();
|
|
$ops = [ '+', '-' ];
|
|
while ( $this->mCur->type == AFPToken::TOP && in_array( $this->mCur->value, $ops ) ) {
|
|
$op = $this->mCur->value;
|
|
$position = $this->mPos;
|
|
$this->move();
|
|
$rightOperand = $this->doLevelMulRels();
|
|
$leftOperand = new AFPTreeNode(
|
|
AFPTreeNode::SUM_REL,
|
|
[ $op, $leftOperand, $rightOperand ],
|
|
$position
|
|
);
|
|
}
|
|
return $leftOperand;
|
|
}
|
|
|
|
/**
|
|
* Handles multiplication and division.
|
|
*
|
|
* @return AFPTreeNode
|
|
*/
|
|
protected function doLevelMulRels() {
|
|
$leftOperand = $this->doLevelPow();
|
|
$ops = [ '*', '/', '%' ];
|
|
while ( $this->mCur->type == AFPToken::TOP && in_array( $this->mCur->value, $ops ) ) {
|
|
$op = $this->mCur->value;
|
|
$position = $this->mPos;
|
|
$this->move();
|
|
$rightOperand = $this->doLevelPow();
|
|
$leftOperand = new AFPTreeNode(
|
|
AFPTreeNode::MUL_REL,
|
|
[ $op, $leftOperand, $rightOperand ],
|
|
$position
|
|
);
|
|
}
|
|
return $leftOperand;
|
|
}
|
|
|
|
/**
|
|
* Handles exponentiation.
|
|
*
|
|
* @return AFPTreeNode
|
|
*/
|
|
protected function doLevelPow() {
|
|
$base = $this->doLevelBoolInvert();
|
|
while ( $this->mCur->type == AFPToken::TOP && $this->mCur->value == '**' ) {
|
|
$position = $this->mPos;
|
|
$this->move();
|
|
$exponent = $this->doLevelBoolInvert();
|
|
$base = new AFPTreeNode( AFPTreeNode::POW, [ $base, $exponent ], $position );
|
|
}
|
|
return $base;
|
|
}
|
|
|
|
/**
|
|
* Handles boolean inversion.
|
|
*
|
|
* @return AFPTreeNode
|
|
*/
|
|
protected function doLevelBoolInvert() {
|
|
if ( $this->mCur->type == AFPToken::TOP && $this->mCur->value == '!' ) {
|
|
$position = $this->mPos;
|
|
$this->move();
|
|
$argument = $this->doLevelKeywordOperators();
|
|
return new AFPTreeNode( AFPTreeNode::BOOL_INVERT, [ $argument ], $position );
|
|
}
|
|
|
|
return $this->doLevelKeywordOperators();
|
|
}
|
|
|
|
/**
|
|
* Handles keyword operators.
|
|
*
|
|
* @return AFPTreeNode
|
|
*/
|
|
protected function doLevelKeywordOperators() {
|
|
$leftOperand = $this->doLevelUnarys();
|
|
$keyword = strtolower( $this->mCur->value );
|
|
if ( $this->mCur->type == AFPToken::TKEYWORD &&
|
|
in_array( $keyword, array_keys( AbuseFilterParser::$mKeywords ) )
|
|
) {
|
|
$position = $this->mPos;
|
|
$this->move();
|
|
$rightOperand = $this->doLevelUnarys();
|
|
|
|
return new AFPTreeNode(
|
|
AFPTreeNode::KEYWORD_OPERATOR,
|
|
[ $keyword, $leftOperand, $rightOperand ],
|
|
$position
|
|
);
|
|
}
|
|
|
|
return $leftOperand;
|
|
}
|
|
|
|
/**
|
|
* Handles unary operators.
|
|
*
|
|
* @return AFPTreeNode
|
|
*/
|
|
protected function doLevelUnarys() {
|
|
$op = $this->mCur->value;
|
|
if ( $this->mCur->type == AFPToken::TOP && ( $op == "+" || $op == "-" ) ) {
|
|
$position = $this->mPos;
|
|
$this->move();
|
|
$argument = $this->doLevelListElements();
|
|
return new AFPTreeNode( AFPTreeNode::UNARY, [ $op, $argument ], $position );
|
|
}
|
|
return $this->doLevelListElements();
|
|
}
|
|
|
|
/**
|
|
* Handles accessing a list element by an offset.
|
|
*
|
|
* @return AFPTreeNode
|
|
* @throws AFPUserVisibleException
|
|
*/
|
|
protected function doLevelListElements() {
|
|
$list = $this->doLevelParenthesis();
|
|
while ( $this->mCur->type == AFPToken::TSQUAREBRACKET && $this->mCur->value == '[' ) {
|
|
$position = $this->mPos;
|
|
$index = $this->doLevelSemicolon();
|
|
$list = new AFPTreeNode( AFPTreeNode::LIST_INDEX, [ $list, $index ], $position );
|
|
|
|
if ( !( $this->mCur->type == AFPToken::TSQUAREBRACKET && $this->mCur->value == ']' ) ) {
|
|
throw new AFPUserVisibleException( 'expectednotfound', $this->mPos,
|
|
[ ']', $this->mCur->type, $this->mCur->value ] );
|
|
}
|
|
$this->move();
|
|
}
|
|
|
|
return $list;
|
|
}
|
|
|
|
/**
|
|
* Handles parenthesis.
|
|
*
|
|
* @return AFPTreeNode
|
|
* @throws AFPUserVisibleException
|
|
*/
|
|
protected function doLevelParenthesis() {
|
|
if ( $this->mCur->type == AFPToken::TBRACE && $this->mCur->value == '(' ) {
|
|
$result = $this->doLevelSemicolon();
|
|
|
|
if ( !( $this->mCur->type == AFPToken::TBRACE && $this->mCur->value == ')' ) ) {
|
|
throw new AFPUserVisibleException(
|
|
'expectednotfound',
|
|
$this->mPos,
|
|
[ ')', $this->mCur->type, $this->mCur->value ]
|
|
);
|
|
}
|
|
$this->move();
|
|
|
|
return $result;
|
|
}
|
|
|
|
return $this->doLevelFunction();
|
|
}
|
|
|
|
/**
|
|
* Handles function calls.
|
|
*
|
|
* @return AFPTreeNode
|
|
* @throws AFPUserVisibleException
|
|
*/
|
|
protected function doLevelFunction() {
|
|
if ( $this->mCur->type == AFPToken::TID &&
|
|
isset( AbuseFilterParser::$mFunctions[$this->mCur->value] )
|
|
) {
|
|
$func = $this->mCur->value;
|
|
$position = $this->mPos;
|
|
$this->move();
|
|
if ( $this->mCur->type != AFPToken::TBRACE || $this->mCur->value != '(' ) {
|
|
throw new AFPUserVisibleException( 'expectednotfound',
|
|
$this->mPos,
|
|
[
|
|
'(',
|
|
$this->mCur->type,
|
|
$this->mCur->value
|
|
]
|
|
);
|
|
}
|
|
|
|
$args = [];
|
|
do {
|
|
$args[] = $this->doLevelSemicolon();
|
|
} while ( $this->mCur->type == AFPToken::TCOMMA );
|
|
|
|
if ( $this->mCur->type != AFPToken::TBRACE || $this->mCur->value != ')' ) {
|
|
throw new AFPUserVisibleException( 'expectednotfound',
|
|
$this->mPos,
|
|
[
|
|
')',
|
|
$this->mCur->type,
|
|
$this->mCur->value
|
|
]
|
|
);
|
|
}
|
|
$this->move();
|
|
|
|
array_unshift( $args, $func );
|
|
return new AFPTreeNode( AFPTreeNode::FUNCTION_CALL, $args, $position );
|
|
}
|
|
|
|
return $this->doLevelAtom();
|
|
}
|
|
|
|
/**
|
|
* Handle literals.
|
|
* @return AFPTreeNode
|
|
* @throws AFPUserVisibleException
|
|
*/
|
|
protected function doLevelAtom() {
|
|
$tok = $this->mCur->value;
|
|
switch ( $this->mCur->type ) {
|
|
case AFPToken::TID:
|
|
case AFPToken::TSTRING:
|
|
case AFPToken::TFLOAT:
|
|
case AFPToken::TINT:
|
|
$result = new AFPTreeNode( AFPTreeNode::ATOM, $this->mCur, $this->mPos );
|
|
break;
|
|
case AFPToken::TKEYWORD:
|
|
if ( in_array( $tok, [ "true", "false", "null" ] ) ) {
|
|
$result = new AFPTreeNode( AFPTreeNode::ATOM, $this->mCur, $this->mPos );
|
|
break;
|
|
}
|
|
|
|
throw new AFPUserVisibleException(
|
|
'unrecognisedkeyword',
|
|
$this->mPos,
|
|
[ $tok ]
|
|
);
|
|
/** @noinspection PhpMissingBreakStatementInspection */
|
|
case AFPToken::TSQUAREBRACKET:
|
|
if ( $this->mCur->value == '[' ) {
|
|
$list = [];
|
|
while ( true ) {
|
|
$this->move();
|
|
if ( $this->mCur->type == AFPToken::TSQUAREBRACKET && $this->mCur->value == ']' ) {
|
|
break;
|
|
}
|
|
|
|
$list[] = $this->doLevelSet();
|
|
|
|
if ( $this->mCur->type == AFPToken::TSQUAREBRACKET && $this->mCur->value == ']' ) {
|
|
break;
|
|
}
|
|
if ( $this->mCur->type != AFPToken::TCOMMA ) {
|
|
throw new AFPUserVisibleException(
|
|
'expectednotfound',
|
|
$this->mPos,
|
|
[ ', or ]', $this->mCur->type, $this->mCur->value ]
|
|
);
|
|
}
|
|
}
|
|
|
|
$result = new AFPTreeNode( AFPTreeNode::LIST_DEFINITION, $list, $this->mPos );
|
|
break;
|
|
}
|
|
|
|
// Fallthrough expected
|
|
default:
|
|
throw new AFPUserVisibleException(
|
|
'unexpectedtoken',
|
|
$this->mPos,
|
|
[
|
|
$this->mCur->type,
|
|
$this->mCur->value
|
|
]
|
|
);
|
|
}
|
|
|
|
$this->move();
|
|
return $result;
|
|
}
|
|
}
|