index.js
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var List = require('../utils/list');
var clone = require('../utils/clone');
var usageUtils = require('./usage');
var clean = require('./clean');
var compress = require('./compress');
var restructureBlock = require('./restructure');
var walkRules = require('../utils/walk').rules;
function readRulesChunk(rules, specialComments) {
var buffer = new List();
var nonSpaceTokenInBuffer = false;
var protectedComment;
rules.nextUntil(rules.head, function(node, item, list) {
if (node.type === 'Comment') {
if (!specialComments || node.value.charAt(0) !== '!') {
list.remove(item);
return;
}
if (nonSpaceTokenInBuffer || protectedComment) {
return true;
}
list.remove(item);
protectedComment = node;
return;
}
if (node.type !== 'Space') {
nonSpaceTokenInBuffer = true;
}
buffer.insert(list.remove(item));
});
return {
comment: protectedComment,
stylesheet: {
type: 'StyleSheet',
info: null,
rules: buffer
}
};
}
function compressChunk(ast, firstAtrulesAllowed, usageData, num, logger) {
logger('Compress block #' + num, null, true);
var seed = 1;
walkRules(ast, function markStylesheets() {
if ('id' in this.stylesheet === false) {
this.stylesheet.firstAtrulesAllowed = firstAtrulesAllowed;
this.stylesheet.id = seed++;
}
});
logger('init', ast);
// remove redundant
clean(ast, usageData);
logger('clean', ast);
// compress nodes
compress(ast, usageData);
logger('compress', ast);
return ast;
}
function getCommentsOption(options) {
var comments = 'comments' in options ? options.comments : 'exclamation';
if (typeof comments === 'boolean') {
comments = comments ? 'exclamation' : false;
} else if (comments !== 'exclamation' && comments !== 'first-exclamation') {
comments = false;
}
return comments;
}
function getRestructureOption(options) {
return 'restructure' in options ? options.restructure :
'restructuring' in options ? options.restructuring :
true;
}
function wrapBlock(block) {
return new List([{
type: 'Ruleset',
selector: {
type: 'Selector',
selectors: new List([{
type: 'SimpleSelector',
sequence: new List([{
type: 'Identifier',
name: 'x'
}])
}])
},
block: block
}]);
}
module.exports = function compress(ast, options) {
ast = ast || { type: 'StyleSheet', info: null, rules: new List() };
options = options || {};
var logger = typeof options.logger === 'function' ? options.logger : Function();
var specialComments = getCommentsOption(options);
var restructuring = getRestructureOption(options);
var firstAtrulesAllowed = true;
var usageData = false;
var inputRules;
var outputRules = new List();
var chunk;
var chunkNum = 1;
var chunkRules;
if (options.clone) {
ast = clone(ast);
}
if (ast.type === 'StyleSheet') {
inputRules = ast.rules;
ast.rules = outputRules;
} else {
inputRules = wrapBlock(ast);
}
if (options.usage) {
usageData = usageUtils.buildIndex(options.usage);
}
do {
chunk = readRulesChunk(inputRules, Boolean(specialComments));
compressChunk(chunk.stylesheet, firstAtrulesAllowed, usageData, chunkNum++, logger);
// structure optimisations
if (restructuring) {
restructureBlock(chunk.stylesheet, usageData, logger);
}
chunkRules = chunk.stylesheet.rules;
if (chunk.comment) {
// add \n before comment if there is another content in outputRules
if (!outputRules.isEmpty()) {
outputRules.insert(List.createItem({
type: 'Raw',
value: '\n'
}));
}
outputRules.insert(List.createItem(chunk.comment));
// add \n after comment if chunk is not empty
if (!chunkRules.isEmpty()) {
outputRules.insert(List.createItem({
type: 'Raw',
value: '\n'
}));
}
}
if (firstAtrulesAllowed && !chunkRules.isEmpty()) {
var lastRule = chunkRules.last();
if (lastRule.type !== 'Atrule' ||
(lastRule.name !== 'import' && lastRule.name !== 'charset')) {
firstAtrulesAllowed = false;
}
}
if (specialComments !== 'exclamation') {
specialComments = false;
}
outputRules.appendList(chunkRules);
} while (!inputRules.isEmpty());
return {
ast: ast
};
};