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var Marker = require('../../tokenizer/marker');
var split = require('../../utils/split');
var DEEP_SELECTOR_PATTERN = /\/deep\//;
var DOUBLE_COLON_PATTERN = /^::/;
var NOT_PSEUDO = ':not';
var PSEUDO_CLASSES_WITH_ARGUMENTS = [
':dir',
':lang',
':not',
':nth-child',
':nth-last-child',
':nth-last-of-type',
':nth-of-type'
];
var RELATION_PATTERN = /[>\+~]/;
var Level = {
DOUBLE_QUOTE: 'double-quote',
SINGLE_QUOTE: 'single-quote',
ROOT: 'root'
};
function isMergeable(selector, mergeablePseudoClasses, mergeablePseudoElements) {
var singleSelectors = split(selector, Marker.COMMA);
var singleSelector;
var i, l;
for (i = 0, l = singleSelectors.length; i < l; i++) {
singleSelector = singleSelectors[i];
if (singleSelector.length === 0 ||
isDeepSelector(singleSelector) ||
(singleSelector.indexOf(Marker.COLON) > -1 && !areMergeable(singleSelector, extractPseudoFrom(singleSelector), mergeablePseudoClasses, mergeablePseudoElements))) {
return false;
}
}
return true;
}
function isDeepSelector(selector) {
return DEEP_SELECTOR_PATTERN.test(selector);
}
function extractPseudoFrom(selector) {
var list = [];
var character;
var buffer = [];
var level = Level.ROOT;
var roundBracketLevel = 0;
var isQuoted;
var isEscaped;
var isPseudo = false;
var isRelation;
var wasColon = false;
var index;
var len;
for (index = 0, len = selector.length; index < len; index++) {
character = selector[index];
isRelation = !isEscaped && RELATION_PATTERN.test(character);
isQuoted = level == Level.DOUBLE_QUOTE || level == Level.SINGLE_QUOTE;
if (isEscaped) {
buffer.push(character);
} else if (character == Marker.DOUBLE_QUOTE && level == Level.ROOT) {
buffer.push(character);
level = Level.DOUBLE_QUOTE;
} else if (character == Marker.DOUBLE_QUOTE && level == Level.DOUBLE_QUOTE) {
buffer.push(character);
level = Level.ROOT;
} else if (character == Marker.SINGLE_QUOTE && level == Level.ROOT) {
buffer.push(character);
level = Level.SINGLE_QUOTE;
} else if (character == Marker.SINGLE_QUOTE && level == Level.SINGLE_QUOTE) {
buffer.push(character);
level = Level.ROOT;
} else if (isQuoted) {
buffer.push(character);
} else if (character == Marker.OPEN_ROUND_BRACKET) {
buffer.push(character);
roundBracketLevel++;
} else if (character == Marker.CLOSE_ROUND_BRACKET && roundBracketLevel == 1 && isPseudo) {
buffer.push(character);
list.push(buffer.join(''));
roundBracketLevel--;
buffer = [];
isPseudo = false;
} else if (character == Marker.CLOSE_ROUND_BRACKET) {
buffer.push(character);
roundBracketLevel--;
} else if (character == Marker.COLON && roundBracketLevel === 0 && isPseudo && !wasColon) {
list.push(buffer.join(''));
buffer = [];
buffer.push(character);
} else if (character == Marker.COLON && roundBracketLevel === 0 && !wasColon) {
buffer = [];
buffer.push(character);
isPseudo = true;
} else if (character == Marker.SPACE && roundBracketLevel === 0 && isPseudo) {
list.push(buffer.join(''));
buffer = [];
isPseudo = false;
} else if (isRelation && roundBracketLevel === 0 && isPseudo) {
list.push(buffer.join(''));
buffer = [];
isPseudo = false;
} else {
buffer.push(character);
}
isEscaped = character == Marker.BACK_SLASH;
wasColon = character == Marker.COLON;
}
if (buffer.length > 0 && isPseudo) {
list.push(buffer.join(''));
}
return list;
}
function areMergeable(selector, matches, mergeablePseudoClasses, mergeablePseudoElements) {
return areAllowed(matches, mergeablePseudoClasses, mergeablePseudoElements) &&
needArguments(matches) &&
(matches.length < 2 || !someIncorrectlyChained(selector, matches)) &&
(matches.length < 2 || !someMixed(matches));
}
function areAllowed(matches, mergeablePseudoClasses, mergeablePseudoElements) {
var match;
var name;
var i, l;
for (i = 0, l = matches.length; i < l; i++) {
match = matches[i];
name = match.indexOf(Marker.OPEN_ROUND_BRACKET) > -1 ?
match.substring(0, match.indexOf(Marker.OPEN_ROUND_BRACKET)) :
match;
if (mergeablePseudoClasses.indexOf(name) === -1 && mergeablePseudoElements.indexOf(name) === -1) {
return false;
}
}
return true;
}
function needArguments(matches) {
var match;
var name;
var bracketOpensAt;
var hasArguments;
var i, l;
for (i = 0, l = matches.length; i < l; i++) {
match = matches[i];
bracketOpensAt = match.indexOf(Marker.OPEN_ROUND_BRACKET);
hasArguments = bracketOpensAt > -1;
name = hasArguments ?
match.substring(0, bracketOpensAt) :
match;
if (hasArguments && PSEUDO_CLASSES_WITH_ARGUMENTS.indexOf(name) == -1) {
return false;
}
if (!hasArguments && PSEUDO_CLASSES_WITH_ARGUMENTS.indexOf(name) > -1) {
return false;
}
}
return true;
}
function someIncorrectlyChained(selector, matches) {
var positionInSelector = 0;
var match;
var matchAt;
var nextMatch;
var nextMatchAt;
var name;
var nextName;
var areChained;
var i, l;
for (i = 0, l = matches.length; i < l; i++) {
match = matches[i];
nextMatch = matches[i + 1];
if (!nextMatch) {
break;
}
matchAt = selector.indexOf(match, positionInSelector);
nextMatchAt = selector.indexOf(match, matchAt + 1);
positionInSelector = nextMatchAt;
areChained = matchAt + match.length == nextMatchAt;
if (areChained) {
name = match.indexOf(Marker.OPEN_ROUND_BRACKET) > -1 ?
match.substring(0, match.indexOf(Marker.OPEN_ROUND_BRACKET)) :
match;
nextName = nextMatch.indexOf(Marker.OPEN_ROUND_BRACKET) > -1 ?
nextMatch.substring(0, nextMatch.indexOf(Marker.OPEN_ROUND_BRACKET)) :
nextMatch;
if (name != NOT_PSEUDO || nextName != NOT_PSEUDO) {
return true;
}
}
}
return false;
}
function someMixed(matches) {
var firstIsPseudoElement = DOUBLE_COLON_PATTERN.test(matches[0]);
var match;
var i, l;
for (i = 0, l = matches.length; i < l; i++) {
match = matches[i];
if (DOUBLE_COLON_PATTERN.test(match) != firstIsPseudoElement) {
return true;
}
}
return false;
}
module.exports = isMergeable;
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