mirror of
https://gerrit.wikimedia.org/r/mediawiki/extensions/AbuseFilter.git
synced 2024-11-15 18:19:38 +00:00
7398730563
As explained on phabricator, they don't work with shortcircuit, so they already fail for all filters using them. Plus IMHO it's an unnecessary deviation from PHP's behaviour, given that this syntax doesn't do what users may expect. Bug: T218906 Change-Id: If9e7545e14044c8dc3b4163bb6fca8ab0683b9fa
624 lines
15 KiB
PHP
624 lines
15 KiB
PHP
<?php
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/**
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* A version of the abuse filter parser that separates parsing the filter and
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* evaluating it into different passes, allowing the parse tree to be cached.
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*
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* @file
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*/
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/**
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* A parser that transforms the text of the filter into a parse tree.
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*/
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class AFPTreeParser {
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// The tokenized representation of the filter parsed.
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public $mTokens;
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// Current token handled by the parser and its position.
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public $mCur, $mPos;
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const CACHE_VERSION = 2;
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/**
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* Create a new instance
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*/
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public function __construct() {
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$this->resetState();
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}
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/**
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* Resets the state
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*/
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public function resetState() {
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$this->mTokens = [];
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$this->mPos = 0;
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}
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/**
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* Advances the parser to the next token in the filter code.
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*/
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protected function move() {
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list( $this->mCur, $this->mPos ) = $this->mTokens[$this->mPos];
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}
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/**
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* getState() function allows parser state to be rollbacked to several tokens
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* back.
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*
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* @return AFPParserState
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*/
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protected function getState() {
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return new AFPParserState( $this->mCur, $this->mPos );
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}
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/**
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* setState() function allows parser state to be rollbacked to several tokens
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* back.
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*
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* @param AFPParserState $state
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*/
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protected function setState( AFPParserState $state ) {
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$this->mCur = $state->token;
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$this->mPos = $state->pos;
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}
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/**
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* Parse the supplied filter source code into a tree.
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*
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* @param string $code
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* @throws AFPUserVisibleException
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* @return AFPTreeNode|null
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*/
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public function parse( $code ) {
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$this->mTokens = AbuseFilterTokenizer::getTokens( $code );
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$this->mPos = 0;
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return $this->doLevelEntry();
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}
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/* Levels */
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/**
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* Handles unexpected characters after the expression.
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* @return AFPTreeNode|null
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* @throws AFPUserVisibleException
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*/
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protected function doLevelEntry() {
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$result = $this->doLevelSemicolon();
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if ( $this->mCur->type !== AFPToken::TNONE ) {
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throw new AFPUserVisibleException(
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'unexpectedatend',
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$this->mPos, [ $this->mCur->type ]
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);
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}
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return $result;
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}
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/**
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* Handles the semicolon operator.
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*
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* @return AFPTreeNode|null
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*/
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protected function doLevelSemicolon() {
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$statements = [];
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do {
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$this->move();
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$position = $this->mPos;
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if ( $this->mCur->type === AFPToken::TNONE ||
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( $this->mCur->type === AFPToken::TBRACE && $this->mCur->value == ')' )
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) {
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break;
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}
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// Allow empty statements.
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if ( $this->mCur->type === AFPToken::TSTATEMENTSEPARATOR ) {
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continue;
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}
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$statements[] = $this->doLevelSet();
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$position = $this->mPos;
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} while ( $this->mCur->type === AFPToken::TSTATEMENTSEPARATOR );
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// Flatten the tree if possible.
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if ( count( $statements ) === 0 ) {
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return null;
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} elseif ( count( $statements ) === 1 ) {
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return $statements[0];
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} else {
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return new AFPTreeNode( AFPTreeNode::SEMICOLON, $statements, $position );
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}
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}
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/**
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* Handles variable assignment.
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*
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* @return AFPTreeNode
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* @throws AFPUserVisibleException
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*/
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protected function doLevelSet() {
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if ( $this->mCur->type === AFPToken::TID ) {
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$varname = $this->mCur->value;
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// Speculatively parse the assignment statement assuming it can
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// potentially be an assignment, but roll back if it isn't.
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$initialState = $this->getState();
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$this->move();
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if ( $this->mCur->type === AFPToken::TOP && $this->mCur->value === ':=' ) {
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$position = $this->mPos;
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$this->move();
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$value = $this->doLevelSet();
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return new AFPTreeNode( AFPTreeNode::ASSIGNMENT, [ $varname, $value ], $position );
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}
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if ( $this->mCur->type === AFPToken::TSQUAREBRACKET && $this->mCur->value === '[' ) {
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$this->move();
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if ( $this->mCur->type === AFPToken::TSQUAREBRACKET && $this->mCur->value === ']' ) {
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$index = 'append';
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} else {
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// Parse index offset.
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$this->setState( $initialState );
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$this->move();
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$index = $this->doLevelSemicolon();
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if ( !( $this->mCur->type === AFPToken::TSQUAREBRACKET && $this->mCur->value === ']' ) ) {
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throw new AFPUserVisibleException( 'expectednotfound', $this->mPos,
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[ ']', $this->mCur->type, $this->mCur->value ] );
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}
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}
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$this->move();
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if ( $this->mCur->type === AFPToken::TOP && $this->mCur->value === ':=' ) {
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$position = $this->mPos;
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$this->move();
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$value = $this->doLevelSet();
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if ( $index === 'append' ) {
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return new AFPTreeNode(
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AFPTreeNode::ARRAY_APPEND, [ $varname, $value ], $position );
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} else {
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return new AFPTreeNode(
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AFPTreeNode::INDEX_ASSIGNMENT,
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[ $varname, $index, $value ],
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$position
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);
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}
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}
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}
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// If we reached this point, we did not find an assignment. Roll back
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// and assume this was just a literal.
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$this->setState( $initialState );
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}
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return $this->doLevelConditions();
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}
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/**
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* Handles ternary operator and if-then-else-end.
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*
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* @return AFPTreeNode
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* @throws AFPUserVisibleException
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*/
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protected function doLevelConditions() {
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if ( $this->mCur->type === AFPToken::TKEYWORD && $this->mCur->value === 'if' ) {
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$position = $this->mPos;
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$this->move();
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$condition = $this->doLevelBoolOps();
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if ( !( $this->mCur->type === AFPToken::TKEYWORD && $this->mCur->value === 'then' ) ) {
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throw new AFPUserVisibleException( 'expectednotfound',
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$this->mPos,
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[
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'then',
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$this->mCur->type,
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$this->mCur->value
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]
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);
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}
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$this->move();
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$valueIfTrue = $this->doLevelConditions();
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if ( !( $this->mCur->type === AFPToken::TKEYWORD && $this->mCur->value === 'else' ) ) {
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throw new AFPUserVisibleException( 'expectednotfound',
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$this->mPos,
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[
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'else',
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$this->mCur->type,
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$this->mCur->value
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]
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);
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}
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$this->move();
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$valueIfFalse = $this->doLevelConditions();
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if ( !( $this->mCur->type === AFPToken::TKEYWORD && $this->mCur->value === 'end' ) ) {
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throw new AFPUserVisibleException( 'expectednotfound',
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$this->mPos,
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[
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'end',
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$this->mCur->type,
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$this->mCur->value
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]
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);
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}
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$this->move();
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return new AFPTreeNode(
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AFPTreeNode::CONDITIONAL,
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[ $condition, $valueIfTrue, $valueIfFalse ],
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$position
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);
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}
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$condition = $this->doLevelBoolOps();
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if ( $this->mCur->type === AFPToken::TOP && $this->mCur->value === '?' ) {
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$position = $this->mPos;
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$this->move();
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$valueIfTrue = $this->doLevelConditions();
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if ( !( $this->mCur->type === AFPToken::TOP && $this->mCur->value === ':' ) ) {
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throw new AFPUserVisibleException( 'expectednotfound',
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$this->mPos,
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[
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':',
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$this->mCur->type,
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$this->mCur->value
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]
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);
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}
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$this->move();
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$valueIfFalse = $this->doLevelConditions();
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return new AFPTreeNode(
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AFPTreeNode::CONDITIONAL,
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[ $condition, $valueIfTrue, $valueIfFalse ],
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$position
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);
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}
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return $condition;
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}
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/**
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* Handles logic operators.
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*
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* @return AFPTreeNode
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*/
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protected function doLevelBoolOps() {
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$leftOperand = $this->doLevelCompares();
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$ops = [ '&', '|', '^' ];
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while ( $this->mCur->type === AFPToken::TOP && in_array( $this->mCur->value, $ops ) ) {
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$op = $this->mCur->value;
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$position = $this->mPos;
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$this->move();
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$rightOperand = $this->doLevelCompares();
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$leftOperand = new AFPTreeNode(
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AFPTreeNode::LOGIC,
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[ $op, $leftOperand, $rightOperand ],
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$position
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);
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}
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return $leftOperand;
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}
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/**
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* Handles comparison operators.
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*
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* @return AFPTreeNode
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*/
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protected function doLevelCompares() {
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$leftOperand = $this->doLevelSumRels();
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$equalityOps = [ '==', '===', '!=', '!==', '=' ];
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$orderOps = [ '<', '>', '<=', '>=' ];
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// Only allow either a single operation, or a combination of a single equalityOps and a single
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// orderOps. This resembles what PHP does, and allows `a < b == c` while rejecting `a < b < c`
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$allowedOps = array_merge( $equalityOps, $orderOps );
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while ( $this->mCur->type === AFPToken::TOP && in_array( $this->mCur->value, $allowedOps ) ) {
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$op = $this->mCur->value;
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$allowedOps = in_array( $op, $equalityOps ) ?
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array_diff( $allowedOps, $equalityOps ) :
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array_diff( $allowedOps, $orderOps );
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$position = $this->mPos;
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$this->move();
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$rightOperand = $this->doLevelSumRels();
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$leftOperand = new AFPTreeNode(
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AFPTreeNode::COMPARE,
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[ $op, $leftOperand, $rightOperand ],
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$position
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);
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}
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return $leftOperand;
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}
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/**
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* Handle addition and subtraction.
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*
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* @return AFPTreeNode
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*/
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protected function doLevelSumRels() {
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$leftOperand = $this->doLevelMulRels();
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$ops = [ '+', '-' ];
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while ( $this->mCur->type === AFPToken::TOP && in_array( $this->mCur->value, $ops ) ) {
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$op = $this->mCur->value;
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$position = $this->mPos;
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$this->move();
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$rightOperand = $this->doLevelMulRels();
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$leftOperand = new AFPTreeNode(
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AFPTreeNode::SUM_REL,
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[ $op, $leftOperand, $rightOperand ],
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$position
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);
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}
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return $leftOperand;
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}
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/**
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* Handles multiplication and division.
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*
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* @return AFPTreeNode
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*/
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protected function doLevelMulRels() {
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$leftOperand = $this->doLevelPow();
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$ops = [ '*', '/', '%' ];
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while ( $this->mCur->type === AFPToken::TOP && in_array( $this->mCur->value, $ops ) ) {
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$op = $this->mCur->value;
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$position = $this->mPos;
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$this->move();
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$rightOperand = $this->doLevelPow();
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$leftOperand = new AFPTreeNode(
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AFPTreeNode::MUL_REL,
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[ $op, $leftOperand, $rightOperand ],
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$position
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);
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}
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return $leftOperand;
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}
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/**
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* Handles exponentiation.
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*
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* @return AFPTreeNode
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*/
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protected function doLevelPow() {
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$base = $this->doLevelBoolInvert();
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while ( $this->mCur->type === AFPToken::TOP && $this->mCur->value === '**' ) {
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$position = $this->mPos;
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$this->move();
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$exponent = $this->doLevelBoolInvert();
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$base = new AFPTreeNode( AFPTreeNode::POW, [ $base, $exponent ], $position );
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}
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return $base;
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}
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/**
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* Handles boolean inversion.
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*
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* @return AFPTreeNode
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*/
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protected function doLevelBoolInvert() {
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if ( $this->mCur->type === AFPToken::TOP && $this->mCur->value === '!' ) {
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$position = $this->mPos;
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$this->move();
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$argument = $this->doLevelKeywordOperators();
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return new AFPTreeNode( AFPTreeNode::BOOL_INVERT, [ $argument ], $position );
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}
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return $this->doLevelKeywordOperators();
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}
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/**
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* Handles keyword operators.
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*
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* @return AFPTreeNode
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*/
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protected function doLevelKeywordOperators() {
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$leftOperand = $this->doLevelUnarys();
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$keyword = strtolower( $this->mCur->value );
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if ( $this->mCur->type === AFPToken::TKEYWORD &&
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isset( AbuseFilterParser::$mKeywords[$keyword] )
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) {
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$position = $this->mPos;
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$this->move();
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$rightOperand = $this->doLevelUnarys();
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return new AFPTreeNode(
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AFPTreeNode::KEYWORD_OPERATOR,
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[ $keyword, $leftOperand, $rightOperand ],
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$position
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);
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}
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return $leftOperand;
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}
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/**
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* Handles unary operators.
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*
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* @return AFPTreeNode
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*/
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protected function doLevelUnarys() {
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$op = $this->mCur->value;
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if ( $this->mCur->type === AFPToken::TOP && ( $op === "+" || $op === "-" ) ) {
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$position = $this->mPos;
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$this->move();
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$argument = $this->doLevelArrayElements();
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return new AFPTreeNode( AFPTreeNode::UNARY, [ $op, $argument ], $position );
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}
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return $this->doLevelArrayElements();
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}
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/**
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* Handles accessing an array element by an offset.
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*
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* @return AFPTreeNode
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* @throws AFPUserVisibleException
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*/
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protected function doLevelArrayElements() {
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$array = $this->doLevelParenthesis();
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while ( $this->mCur->type === AFPToken::TSQUAREBRACKET && $this->mCur->value === '[' ) {
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$position = $this->mPos;
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$index = $this->doLevelSemicolon();
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$array = new AFPTreeNode( AFPTreeNode::ARRAY_INDEX, [ $array, $index ], $position );
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if ( !( $this->mCur->type === AFPToken::TSQUAREBRACKET && $this->mCur->value === ']' ) ) {
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throw new AFPUserVisibleException( 'expectednotfound', $this->mPos,
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[ ']', $this->mCur->type, $this->mCur->value ] );
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}
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$this->move();
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}
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return $array;
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}
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/**
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* Handles parenthesis.
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*
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* @return AFPTreeNode
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* @throws AFPUserVisibleException
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*/
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protected function doLevelParenthesis() {
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if ( $this->mCur->type === AFPToken::TBRACE && $this->mCur->value === '(' ) {
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$result = $this->doLevelSemicolon();
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if ( !( $this->mCur->type === AFPToken::TBRACE && $this->mCur->value === ')' ) ) {
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throw new AFPUserVisibleException(
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'expectednotfound',
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$this->mPos,
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[ ')', $this->mCur->type, $this->mCur->value ]
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);
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}
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$this->move();
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return $result;
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}
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return $this->doLevelFunction();
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}
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/**
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* Handles function calls.
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*
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* @return AFPTreeNode
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* @throws AFPUserVisibleException
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*/
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protected function doLevelFunction() {
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if ( $this->mCur->type === AFPToken::TID &&
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isset( AbuseFilterParser::$mFunctions[$this->mCur->value] )
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) {
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$func = $this->mCur->value;
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$position = $this->mPos;
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$this->move();
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if ( $this->mCur->type !== AFPToken::TBRACE || $this->mCur->value !== '(' ) {
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throw new AFPUserVisibleException( 'expectednotfound',
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$this->mPos,
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[
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'(',
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$this->mCur->type,
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$this->mCur->value
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]
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);
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}
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$args = [];
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do {
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$args[] = $this->doLevelSemicolon();
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} while ( $this->mCur->type === AFPToken::TCOMMA );
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if ( $this->mCur->type !== AFPToken::TBRACE || $this->mCur->value !== ')' ) {
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throw new AFPUserVisibleException( 'expectednotfound',
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$this->mPos,
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|
[
|
|
')',
|
|
$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 === '[' ) {
|
|
$array = [];
|
|
while ( true ) {
|
|
$this->move();
|
|
if ( $this->mCur->type === AFPToken::TSQUAREBRACKET && $this->mCur->value === ']' ) {
|
|
break;
|
|
}
|
|
|
|
$array[] = $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::ARRAY_DEFINITION, $array, $this->mPos );
|
|
break;
|
|
}
|
|
|
|
// Fallthrough expected
|
|
default:
|
|
throw new AFPUserVisibleException(
|
|
'unexpectedtoken',
|
|
$this->mPos,
|
|
[
|
|
$this->mCur->type,
|
|
$this->mCur->value
|
|
]
|
|
);
|
|
}
|
|
|
|
$this->move();
|
|
return $result;
|
|
}
|
|
}
|