1 files changed, 157 insertions, 0 deletions
diff --git a/node_modules/csso/lib/compressor/restructure/8-restructRuleset.js b/node_modules/csso/lib/compressor/restructure/8-restructRuleset.js
new file mode 100644
index 00000000..9a9e545f
--- /dev/null
+++ b/node_modules/csso/lib/compressor/restructure/8-restructRuleset.js
@@ -0,0 +1,157 @@
+var List = require('../../utils/list.js');
+var utils = require('./utils.js');
+var walkRulesRight = require('../../utils/walk.js').rulesRight;
+
+function calcSelectorLength(list) {
+    var length = 0;
+
+    list.each(function(data) {
+        length += data.id.length + 1;
+    });
+
+    return length - 1;
+}
+
+function calcDeclarationsLength(tokens) {
+    var length = 0;
+
+    for (var i = 0; i < tokens.length; i++) {
+        length += tokens[i].length;
+    }
+
+    return (
+        length +          // declarations
+        tokens.length - 1 // delimeters
+    );
+}
+
+function processRuleset(node, item, list) {
+    var avoidRulesMerge = this.stylesheet.avoidRulesMerge;
+    var selectors = node.selector.selectors;
+    var block = node.block;
+    var disallowDownMarkers = Object.create(null);
+    var allowMergeUp = true;
+    var allowMergeDown = true;
+
+    list.prevUntil(item.prev, function(prev, prevItem) {
+        // skip non-ruleset node if safe
+        if (prev.type !== 'Ruleset') {
+            return utils.unsafeToSkipNode.call(selectors, prev);
+        }
+
+        var prevSelectors = prev.selector.selectors;
+        var prevBlock = prev.block;
+
+        if (node.pseudoSignature !== prev.pseudoSignature) {
+            return true;
+        }
+
+        allowMergeDown = !prevSelectors.some(function(selector) {
+            return selector.compareMarker in disallowDownMarkers;
+        });
+
+        // try prev ruleset if simpleselectors has no equal specifity and element selector
+        if (!allowMergeDown && !allowMergeUp) {
+            return true;
+        }
+
+        // try to join by selectors
+        if (allowMergeUp && utils.isEqualLists(prevSelectors, selectors)) {
+            prevBlock.declarations.appendList(block.declarations);
+            list.remove(item);
+            return true;
+        }
+
+        // try to join by properties
+        var diff = utils.compareDeclarations(block.declarations, prevBlock.declarations);
+
+        // console.log(diff.eq, diff.ne1, diff.ne2);
+
+        if (diff.eq.length) {
+            if (!diff.ne1.length && !diff.ne2.length) {
+                // equal blocks
+                if (allowMergeDown) {
+                    utils.addSelectors(selectors, prevSelectors);
+                    list.remove(prevItem);
+                }
+
+                return true;
+            } else if (!avoidRulesMerge) { /* probably we don't need to prevent those merges for @keyframes
+                                              TODO: need to be checked */
+
+                if (diff.ne1.length && !diff.ne2.length) {
+                    // prevBlock is subset block
+                    var selectorLength = calcSelectorLength(selectors);
+                    var blockLength = calcDeclarationsLength(diff.eq); // declarations length
+
+                    if (allowMergeUp && selectorLength < blockLength) {
+                        utils.addSelectors(prevSelectors, selectors);
+                        block.declarations = new List(diff.ne1);
+                    }
+                } else if (!diff.ne1.length && diff.ne2.length) {
+                    // node is subset of prevBlock
+                    var selectorLength = calcSelectorLength(prevSelectors);
+                    var blockLength = calcDeclarationsLength(diff.eq); // declarations length
+
+                    if (allowMergeDown && selectorLength < blockLength) {
+                        utils.addSelectors(selectors, prevSelectors);
+                        prevBlock.declarations = new List(diff.ne2);
+                    }
+                } else {
+                    // diff.ne1.length && diff.ne2.length
+                    // extract equal block
+                    var newSelector = {
+                        type: 'Selector',
+                        info: {},
+                        selectors: utils.addSelectors(prevSelectors.copy(), selectors)
+                    };
+                    var newBlockLength = calcSelectorLength(newSelector.selectors) + 2; // selectors length + curly braces length
+                    var blockLength = calcDeclarationsLength(diff.eq); // declarations length
+
+                    // create new ruleset if declarations length greater than
+                    // ruleset description overhead
+                    if (allowMergeDown && blockLength >= newBlockLength) {
+                        var newRuleset = {
+                            type: 'Ruleset',
+                            info: {},
+                            pseudoSignature: node.pseudoSignature,
+                            selector: newSelector,
+                            block: {
+                                type: 'Block',
+                                info: {},
+                                declarations: new List(diff.eq)
+                            }
+                        };
+
+                        block.declarations = new List(diff.ne1);
+                        prevBlock.declarations = new List(diff.ne2.concat(diff.ne2overrided));
+                        list.insert(list.createItem(newRuleset), prevItem);
+                        return true;
+                    }
+                }
+            }
+        }
+
+        if (allowMergeUp) {
+            // TODO: disallow up merge only if any property interception only (i.e. diff.ne2overrided.length > 0);
+            // await property families to find property interception correctly
+            allowMergeUp = !prevSelectors.some(function(prevSelector) {
+                return selectors.some(function(selector) {
+                    return selector.compareMarker === prevSelector.compareMarker;
+                });
+            });
+        }
+
+        prevSelectors.each(function(data) {
+            disallowDownMarkers[data.compareMarker] = true;
+        });
+    });
+};
+
+module.exports = function restructRuleset(ast) {
+    walkRulesRight(ast, function(node, item, list) {
+        if (node.type === 'Ruleset') {
+            processRuleset.call(this, node, item, list);
+        }
+    });
+};