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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;
}
};