1 files changed, 141 insertions, 0 deletions
diff --git a/node_modules/csso/lib/compressor/restructure/utils.js b/node_modules/csso/lib/compressor/restructure/utils.js
new file mode 100644
index 00000000..70c92c51
--- /dev/null
+++ b/node_modules/csso/lib/compressor/restructure/utils.js
@@ -0,0 +1,141 @@
+var hasOwnProperty = Object.prototype.hasOwnProperty;
+
+function isEqualLists(a, b) {
+    var cursor1 = a.head;
+    var cursor2 = b.head;
+
+    while (cursor1 !== null && cursor2 !== null && cursor1.data.id === cursor2.data.id) {
+        cursor1 = cursor1.next;
+        cursor2 = cursor2.next;
+    }
+
+    return cursor1 === null && cursor2 === null;
+}
+
+function isEqualDeclarations(a, b) {
+    var cursor1 = a.head;
+    var cursor2 = b.head;
+
+    while (cursor1 !== null && cursor2 !== null && cursor1.data.id === cursor2.data.id) {
+        cursor1 = cursor1.next;
+        cursor2 = cursor2.next;
+    }
+
+    return cursor1 === null && cursor2 === null;
+}
+
+function compareDeclarations(declarations1, declarations2) {
+    var result = {
+        eq: [],
+        ne1: [],
+        ne2: [],
+        ne2overrided: []
+    };
+
+    var fingerprints = Object.create(null);
+    var declarations2hash = Object.create(null);
+
+    for (var cursor = declarations2.head; cursor; cursor = cursor.next)  {
+        declarations2hash[cursor.data.id] = true;
+    }
+
+    for (var cursor = declarations1.head; cursor; cursor = cursor.next)  {
+        var data = cursor.data;
+
+        if (data.fingerprint) {
+            fingerprints[data.fingerprint] = data.value.important;
+        }
+
+        if (declarations2hash[data.id]) {
+            declarations2hash[data.id] = false;
+            result.eq.push(data);
+        } else {
+            result.ne1.push(data);
+        }
+    }
+
+    for (var cursor = declarations2.head; cursor; cursor = cursor.next)  {
+        var data = cursor.data;
+
+        if (declarations2hash[data.id]) {
+            // if declarations1 has overriding declaration, this is not a difference
+            // but take in account !important - prev should be equal or greater than follow
+            if (hasOwnProperty.call(fingerprints, data.fingerprint) &&
+                Number(fingerprints[data.fingerprint]) >= Number(data.value.important)) {
+                result.ne2overrided.push(data);
+            } else {
+                result.ne2.push(data);
+            }
+        }
+    }
+
+    return result;
+}
+
+function addSelectors(dest, source) {
+    source.each(function(sourceData) {
+        var newStr = sourceData.id;
+        var cursor = dest.head;
+
+        while (cursor) {
+            var nextStr = cursor.data.id;
+
+            if (nextStr === newStr) {
+                return;
+            }
+
+            if (nextStr > newStr) {
+                break;
+            }
+
+            cursor = cursor.next;
+        }
+
+        dest.insert(dest.createItem(sourceData), cursor);
+    });
+
+    return dest;
+}
+
+// check if simpleselectors has no equal specificity and element selector
+function hasSimilarSelectors(selectors1, selectors2) {
+    return selectors1.some(function(a) {
+        return selectors2.some(function(b) {
+            return a.compareMarker === b.compareMarker;
+        });
+    });
+}
+
+// test node can't to be skipped
+function unsafeToSkipNode(node) {
+    switch (node.type) {
+        case 'Ruleset':
+            // unsafe skip ruleset with selector similarities
+            return hasSimilarSelectors(node.selector.selectors, this);
+
+        case 'Atrule':
+            // can skip at-rules with blocks
+            if (node.block) {
+                // non-stylesheet blocks are safe to skip since have no selectors
+                if (node.block.type !== 'StyleSheet') {
+                    return false;
+                }
+
+                // unsafe skip at-rule if block contains something unsafe to skip
+                return node.block.rules.some(unsafeToSkipNode, this);
+            }
+            break;
+    }
+
+    // unsafe by default
+    return true;
+}
+
+module.exports = {
+    isEqualLists: isEqualLists,
+    isEqualDeclarations: isEqualDeclarations,
+    compareDeclarations: compareDeclarations,
+    addSelectors: addSelectors,
+    hasSimilarSelectors: hasSimilarSelectors,
+    unsafeToSkipNode: unsafeToSkipNode
+};