first commit

build/node_modules/csso/lib/compressor/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
+    };
+};