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- var hasOwnProperty = Object.prototype.hasOwnProperty;
- var matchGraph = require('./match-graph');
- var MATCH = matchGraph.MATCH;
- var MISMATCH = matchGraph.MISMATCH;
- var DISALLOW_EMPTY = matchGraph.DISALLOW_EMPTY;
- var TYPE = require('../tokenizer/const').TYPE;
- var STUB = 0;
- var TOKEN = 1;
- var OPEN_SYNTAX = 2;
- var CLOSE_SYNTAX = 3;
- var EXIT_REASON_MATCH = 'Match';
- var EXIT_REASON_MISMATCH = 'Mismatch';
- var EXIT_REASON_ITERATION_LIMIT = 'Maximum iteration number exceeded (please fill an issue on https://github.com/csstree/csstree/issues)';
- var ITERATION_LIMIT = 15000;
- var totalIterationCount = 0;
- function reverseList(list) {
- var prev = null;
- var next = null;
- var item = list;
- while (item !== null) {
- next = item.prev;
- item.prev = prev;
- prev = item;
- item = next;
- }
- return prev;
- }
- function areStringsEqualCaseInsensitive(testStr, referenceStr) {
- if (testStr.length !== referenceStr.length) {
- return false;
- }
- for (var i = 0; i < testStr.length; i++) {
- var testCode = testStr.charCodeAt(i);
- var referenceCode = referenceStr.charCodeAt(i);
- // testCode.toLowerCase() for U+0041 LATIN CAPITAL LETTER A (A) .. U+005A LATIN CAPITAL LETTER Z (Z).
- if (testCode >= 0x0041 && testCode <= 0x005A) {
- testCode = testCode | 32;
- }
- if (testCode !== referenceCode) {
- return false;
- }
- }
- return true;
- }
- function isCommaContextStart(token) {
- if (token === null) {
- return true;
- }
- return (
- token.type === TYPE.Comma ||
- token.type === TYPE.Function ||
- token.type === TYPE.LeftParenthesis ||
- token.type === TYPE.LeftSquareBracket ||
- token.type === TYPE.LeftCurlyBracket ||
- token.type === TYPE.Delim
- );
- }
- function isCommaContextEnd(token) {
- if (token === null) {
- return true;
- }
- return (
- token.type === TYPE.RightParenthesis ||
- token.type === TYPE.RightSquareBracket ||
- token.type === TYPE.RightCurlyBracket ||
- token.type === TYPE.Delim
- );
- }
- function internalMatch(tokens, state, syntaxes) {
- function moveToNextToken() {
- do {
- tokenIndex++;
- token = tokenIndex < tokens.length ? tokens[tokenIndex] : null;
- } while (token !== null && (token.type === TYPE.WhiteSpace || token.type === TYPE.Comment));
- }
- function getNextToken(offset) {
- var nextIndex = tokenIndex + offset;
- return nextIndex < tokens.length ? tokens[nextIndex] : null;
- }
- function stateSnapshotFromSyntax(nextState, prev) {
- return {
- nextState: nextState,
- matchStack: matchStack,
- syntaxStack: syntaxStack,
- thenStack: thenStack,
- tokenIndex: tokenIndex,
- prev: prev
- };
- }
- function pushThenStack(nextState) {
- thenStack = {
- nextState: nextState,
- matchStack: matchStack,
- syntaxStack: syntaxStack,
- prev: thenStack
- };
- }
- function pushElseStack(nextState) {
- elseStack = stateSnapshotFromSyntax(nextState, elseStack);
- }
- function addTokenToMatch() {
- matchStack = {
- type: TOKEN,
- syntax: state.syntax,
- token: token,
- prev: matchStack
- };
- moveToNextToken();
- syntaxStash = null;
- if (tokenIndex > longestMatch) {
- longestMatch = tokenIndex;
- }
- }
- function openSyntax() {
- syntaxStack = {
- syntax: state.syntax,
- opts: state.syntax.opts || (syntaxStack !== null && syntaxStack.opts) || null,
- prev: syntaxStack
- };
- matchStack = {
- type: OPEN_SYNTAX,
- syntax: state.syntax,
- token: matchStack.token,
- prev: matchStack
- };
- }
- function closeSyntax() {
- if (matchStack.type === OPEN_SYNTAX) {
- matchStack = matchStack.prev;
- } else {
- matchStack = {
- type: CLOSE_SYNTAX,
- syntax: syntaxStack.syntax,
- token: matchStack.token,
- prev: matchStack
- };
- }
- syntaxStack = syntaxStack.prev;
- }
- var syntaxStack = null;
- var thenStack = null;
- var elseStack = null;
- // null – stashing allowed, nothing stashed
- // false – stashing disabled, nothing stashed
- // anithing else – fail stashable syntaxes, some syntax stashed
- var syntaxStash = null;
- var iterationCount = 0; // count iterations and prevent infinite loop
- var exitReason = null;
- var token = null;
- var tokenIndex = -1;
- var longestMatch = 0;
- var matchStack = {
- type: STUB,
- syntax: null,
- token: null,
- prev: null
- };
- moveToNextToken();
- while (exitReason === null && ++iterationCount < ITERATION_LIMIT) {
- // function mapList(list, fn) {
- // var result = [];
- // while (list) {
- // result.unshift(fn(list));
- // list = list.prev;
- // }
- // return result;
- // }
- // console.log('--\n',
- // '#' + iterationCount,
- // require('util').inspect({
- // match: mapList(matchStack, x => x.type === TOKEN ? x.token && x.token.value : x.syntax ? ({ [OPEN_SYNTAX]: '<', [CLOSE_SYNTAX]: '</' }[x.type] || x.type) + '!' + x.syntax.name : null),
- // token: token && token.value,
- // tokenIndex,
- // syntax: syntax.type + (syntax.id ? ' #' + syntax.id : '')
- // }, { depth: null })
- // );
- switch (state.type) {
- case 'Match':
- if (thenStack === null) {
- // turn to MISMATCH when some tokens left unmatched
- if (token !== null) {
- // doesn't mismatch if just one token left and it's an IE hack
- if (tokenIndex !== tokens.length - 1 || (token.value !== '\\0' && token.value !== '\\9')) {
- state = MISMATCH;
- break;
- }
- }
- // break the main loop, return a result - MATCH
- exitReason = EXIT_REASON_MATCH;
- break;
- }
- // go to next syntax (`then` branch)
- state = thenStack.nextState;
- // check match is not empty
- if (state === DISALLOW_EMPTY) {
- if (thenStack.matchStack === matchStack) {
- state = MISMATCH;
- break;
- } else {
- state = MATCH;
- }
- }
- // close syntax if needed
- while (thenStack.syntaxStack !== syntaxStack) {
- closeSyntax();
- }
- // pop stack
- thenStack = thenStack.prev;
- break;
- case 'Mismatch':
- // when some syntax is stashed
- if (syntaxStash !== null && syntaxStash !== false) {
- // there is no else branches or a branch reduce match stack
- if (elseStack === null || tokenIndex > elseStack.tokenIndex) {
- // restore state from the stash
- elseStack = syntaxStash;
- syntaxStash = false; // disable stashing
- }
- } else if (elseStack === null) {
- // no else branches -> break the main loop
- // return a result - MISMATCH
- exitReason = EXIT_REASON_MISMATCH;
- break;
- }
- // go to next syntax (`else` branch)
- state = elseStack.nextState;
- // restore all the rest stack states
- thenStack = elseStack.thenStack;
- syntaxStack = elseStack.syntaxStack;
- matchStack = elseStack.matchStack;
- tokenIndex = elseStack.tokenIndex;
- token = tokenIndex < tokens.length ? tokens[tokenIndex] : null;
- // pop stack
- elseStack = elseStack.prev;
- break;
- case 'MatchGraph':
- state = state.match;
- break;
- case 'If':
- // IMPORTANT: else stack push must go first,
- // since it stores the state of thenStack before changes
- if (state.else !== MISMATCH) {
- pushElseStack(state.else);
- }
- if (state.then !== MATCH) {
- pushThenStack(state.then);
- }
- state = state.match;
- break;
- case 'MatchOnce':
- state = {
- type: 'MatchOnceBuffer',
- syntax: state,
- index: 0,
- mask: 0
- };
- break;
- case 'MatchOnceBuffer':
- var terms = state.syntax.terms;
- if (state.index === terms.length) {
- // no matches at all or it's required all terms to be matched
- if (state.mask === 0 || state.syntax.all) {
- state = MISMATCH;
- break;
- }
- // a partial match is ok
- state = MATCH;
- break;
- }
- // all terms are matched
- if (state.mask === (1 << terms.length) - 1) {
- state = MATCH;
- break;
- }
- for (; state.index < terms.length; state.index++) {
- var matchFlag = 1 << state.index;
- if ((state.mask & matchFlag) === 0) {
- // IMPORTANT: else stack push must go first,
- // since it stores the state of thenStack before changes
- pushElseStack(state);
- pushThenStack({
- type: 'AddMatchOnce',
- syntax: state.syntax,
- mask: state.mask | matchFlag
- });
- // match
- state = terms[state.index++];
- break;
- }
- }
- break;
- case 'AddMatchOnce':
- state = {
- type: 'MatchOnceBuffer',
- syntax: state.syntax,
- index: 0,
- mask: state.mask
- };
- break;
- case 'Enum':
- if (token !== null) {
- var name = token.value.toLowerCase();
- // drop \0 and \9 hack from keyword name
- if (name.indexOf('\\') !== -1) {
- name = name.replace(/\\[09].*$/, '');
- }
- if (hasOwnProperty.call(state.map, name)) {
- state = state.map[name];
- break;
- }
- }
- state = MISMATCH;
- break;
- case 'Generic':
- var opts = syntaxStack !== null ? syntaxStack.opts : null;
- var lastTokenIndex = tokenIndex + Math.floor(state.fn(token, getNextToken, opts));
- if (!isNaN(lastTokenIndex) && lastTokenIndex > tokenIndex) {
- while (tokenIndex < lastTokenIndex) {
- addTokenToMatch();
- }
- state = MATCH;
- } else {
- state = MISMATCH;
- }
- break;
- case 'Type':
- case 'Property':
- var syntaxDict = state.type === 'Type' ? 'types' : 'properties';
- var dictSyntax = hasOwnProperty.call(syntaxes, syntaxDict) ? syntaxes[syntaxDict][state.name] : null;
- if (!dictSyntax || !dictSyntax.match) {
- throw new Error(
- 'Bad syntax reference: ' +
- (state.type === 'Type'
- ? '<' + state.name + '>'
- : '<\'' + state.name + '\'>')
- );
- }
- // stash a syntax for types with low priority
- if (syntaxStash !== false && token !== null && state.type === 'Type') {
- var lowPriorityMatching =
- // https://drafts.csswg.org/css-values-4/#custom-idents
- // When parsing positionally-ambiguous keywords in a property value, a <custom-ident> production
- // can only claim the keyword if no other unfulfilled production can claim it.
- (state.name === 'custom-ident' && token.type === TYPE.Ident) ||
- // https://drafts.csswg.org/css-values-4/#lengths
- // ... if a `0` could be parsed as either a <number> or a <length> in a property (such as line-height),
- // it must parse as a <number>
- (state.name === 'length' && token.value === '0');
- if (lowPriorityMatching) {
- if (syntaxStash === null) {
- syntaxStash = stateSnapshotFromSyntax(state, elseStack);
- }
- state = MISMATCH;
- break;
- }
- }
- openSyntax();
- state = dictSyntax.match;
- break;
- case 'Keyword':
- var name = state.name;
- if (token !== null) {
- var keywordName = token.value;
- // drop \0 and \9 hack from keyword name
- if (keywordName.indexOf('\\') !== -1) {
- keywordName = keywordName.replace(/\\[09].*$/, '');
- }
- if (areStringsEqualCaseInsensitive(keywordName, name)) {
- addTokenToMatch();
- state = MATCH;
- break;
- }
- }
- state = MISMATCH;
- break;
- case 'AtKeyword':
- case 'Function':
- if (token !== null && areStringsEqualCaseInsensitive(token.value, state.name)) {
- addTokenToMatch();
- state = MATCH;
- break;
- }
- state = MISMATCH;
- break;
- case 'Token':
- if (token !== null && token.value === state.value) {
- addTokenToMatch();
- state = MATCH;
- break;
- }
- state = MISMATCH;
- break;
- case 'Comma':
- if (token !== null && token.type === TYPE.Comma) {
- if (isCommaContextStart(matchStack.token)) {
- state = MISMATCH;
- } else {
- addTokenToMatch();
- state = isCommaContextEnd(token) ? MISMATCH : MATCH;
- }
- } else {
- state = isCommaContextStart(matchStack.token) || isCommaContextEnd(token) ? MATCH : MISMATCH;
- }
- break;
- case 'String':
- var string = '';
- for (var lastTokenIndex = tokenIndex; lastTokenIndex < tokens.length && string.length < state.value.length; lastTokenIndex++) {
- string += tokens[lastTokenIndex].value;
- }
- if (areStringsEqualCaseInsensitive(string, state.value)) {
- while (tokenIndex < lastTokenIndex) {
- addTokenToMatch();
- }
- state = MATCH;
- } else {
- state = MISMATCH;
- }
- break;
- default:
- throw new Error('Unknown node type: ' + state.type);
- }
- }
- totalIterationCount += iterationCount;
- switch (exitReason) {
- case null:
- console.warn('[csstree-match] BREAK after ' + ITERATION_LIMIT + ' iterations');
- exitReason = EXIT_REASON_ITERATION_LIMIT;
- matchStack = null;
- break;
- case EXIT_REASON_MATCH:
- while (syntaxStack !== null) {
- closeSyntax();
- }
- break;
- default:
- matchStack = null;
- }
- return {
- tokens: tokens,
- reason: exitReason,
- iterations: iterationCount,
- match: matchStack,
- longestMatch: longestMatch
- };
- }
- function matchAsList(tokens, matchGraph, syntaxes) {
- var matchResult = internalMatch(tokens, matchGraph, syntaxes || {});
- if (matchResult.match !== null) {
- var item = reverseList(matchResult.match).prev;
- matchResult.match = [];
- while (item !== null) {
- switch (item.type) {
- case STUB:
- break;
- case OPEN_SYNTAX:
- case CLOSE_SYNTAX:
- matchResult.match.push({
- type: item.type,
- syntax: item.syntax
- });
- break;
- default:
- matchResult.match.push({
- token: item.token.value,
- node: item.token.node
- });
- break;
- }
- item = item.prev;
- }
- }
- return matchResult;
- }
- function matchAsTree(tokens, matchGraph, syntaxes) {
- var matchResult = internalMatch(tokens, matchGraph, syntaxes || {});
- if (matchResult.match === null) {
- return matchResult;
- }
- var item = matchResult.match;
- var host = matchResult.match = {
- syntax: matchGraph.syntax || null,
- match: []
- };
- var hostStack = [host];
- // revert a list and start with 2nd item since 1st is a stub item
- item = reverseList(item).prev;
- // build a tree
- while (item !== null) {
- switch (item.type) {
- case OPEN_SYNTAX:
- host.match.push(host = {
- syntax: item.syntax,
- match: []
- });
- hostStack.push(host);
- break;
- case CLOSE_SYNTAX:
- hostStack.pop();
- host = hostStack[hostStack.length - 1];
- break;
- default:
- host.match.push({
- syntax: item.syntax || null,
- token: item.token.value,
- node: item.token.node
- });
- }
- item = item.prev;
- }
- return matchResult;
- }
- module.exports = {
- matchAsList: matchAsList,
- matchAsTree: matchAsTree,
- getTotalIterationCount: function() {
- return totalIterationCount;
- }
- };
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