104 lines
3.1 KiB
JavaScript
104 lines
3.1 KiB
JavaScript
var canReorder = require('./reorderable').canReorder;
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var canReorderSingle = require('./reorderable').canReorderSingle;
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var extractProperties = require('./extract-properties');
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var rulesOverlap = require('./rules-overlap');
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var serializeRules = require('../../writer/one-time').rules;
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var OptimizationLevel = require('../../options/optimization-level').OptimizationLevel;
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var Token = require('../../tokenizer/token');
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function mergeMediaQueries(tokens, context) {
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var mergeSemantically = context.options.level[OptimizationLevel.Two].mergeSemantically;
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var specificityCache = context.cache.specificity;
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var candidates = {};
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var reduced = [];
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for (var i = tokens.length - 1; i >= 0; i--) {
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var token = tokens[i];
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if (token[0] != Token.NESTED_BLOCK) {
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continue;
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}
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var key = serializeRules(token[1]);
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var candidate = candidates[key];
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if (!candidate) {
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candidate = [];
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candidates[key] = candidate;
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}
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candidate.push(i);
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}
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for (var name in candidates) {
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var positions = candidates[name];
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positionLoop:
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for (var j = positions.length - 1; j > 0; j--) {
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var positionOne = positions[j];
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var tokenOne = tokens[positionOne];
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var positionTwo = positions[j - 1];
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var tokenTwo = tokens[positionTwo];
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directionLoop:
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for (var direction = 1; direction >= -1; direction -= 2) {
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var topToBottom = direction == 1;
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var from = topToBottom ? positionOne + 1 : positionTwo - 1;
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var to = topToBottom ? positionTwo : positionOne;
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var delta = topToBottom ? 1 : -1;
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var source = topToBottom ? tokenOne : tokenTwo;
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var target = topToBottom ? tokenTwo : tokenOne;
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var movedProperties = extractProperties(source);
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while (from != to) {
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var traversedProperties = extractProperties(tokens[from]);
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from += delta;
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if (mergeSemantically && allSameRulePropertiesCanBeReordered(movedProperties, traversedProperties, specificityCache)) {
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continue;
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}
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if (!canReorder(movedProperties, traversedProperties, specificityCache))
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continue directionLoop;
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}
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target[2] = topToBottom ?
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source[2].concat(target[2]) :
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target[2].concat(source[2]);
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source[2] = [];
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reduced.push(target);
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continue positionLoop;
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}
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}
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}
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return reduced;
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}
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function allSameRulePropertiesCanBeReordered(movedProperties, traversedProperties, specificityCache) {
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var movedProperty;
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var movedRule;
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var traversedProperty;
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var traversedRule;
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var i, l;
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var j, m;
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for (i = 0, l = movedProperties.length; i < l; i++) {
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movedProperty = movedProperties[i];
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movedRule = movedProperty[5];
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for (j = 0, m = traversedProperties.length; j < m; j++) {
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traversedProperty = traversedProperties[j];
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traversedRule = traversedProperty[5];
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if (rulesOverlap(movedRule, traversedRule, true) && !canReorderSingle(movedProperty, traversedProperty, specificityCache)) {
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return false;
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}
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}
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}
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return true;
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}
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module.exports = mergeMediaQueries;
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