1 files changed, 114 insertions, 0 deletions
diff --git a/bin/lib/less/tree/media.js b/bin/lib/less/tree/media.js
new file mode 100644
index 00000000..2b7b26e5
--- /dev/null
+++ b/bin/lib/less/tree/media.js
@@ -0,0 +1,114 @@
+(function (tree) {
+
+tree.Media = function (value, features) {
+    var el = new(tree.Element)('&', null, 0),
+        selectors = [new(tree.Selector)([el])];
+
+    this.features = new(tree.Value)(features);
+    this.ruleset = new(tree.Ruleset)(selectors, value);
+    this.ruleset.allowImports = true;
+};
+tree.Media.prototype = {
+    toCSS: function (ctx, env) {
+        var features = this.features.toCSS(env);
+
+        this.ruleset.root = (ctx.length === 0 || ctx[0].multiMedia);
+        return '@media ' + features + (env.compress ? '{' : ' {\n  ') +
+               this.ruleset.toCSS(ctx, env).trim().replace(/\n/g, '\n  ') +
+                           (env.compress ? '}': '\n}\n');
+    },
+    eval: function (env) {
+        if (!env.mediaBlocks) {
+            env.mediaBlocks = [];
+            env.mediaPath = [];
+        }
+        
+        var blockIndex = env.mediaBlocks.length;
+        env.mediaPath.push(this);
+        env.mediaBlocks.push(this);
+
+        var media = new(tree.Media)([], []);
+        media.features = this.features.eval(env);
+        
+        env.frames.unshift(this.ruleset);
+        media.ruleset = this.ruleset.eval(env);
+        env.frames.shift();
+        
+        env.mediaBlocks[blockIndex] = media;
+        env.mediaPath.pop();
+
+        return env.mediaPath.length === 0 ? media.evalTop(env) :
+                    media.evalNested(env)
+    },
+    variable: function (name) { return tree.Ruleset.prototype.variable.call(this.ruleset, name) },
+    find: function () { return tree.Ruleset.prototype.find.apply(this.ruleset, arguments) },
+    rulesets: function () { return tree.Ruleset.prototype.rulesets.apply(this.ruleset) },
+
+    evalTop: function (env) {
+        var result = this;
+
+        // Render all dependent Media blocks.
+        if (env.mediaBlocks.length > 1) {
+            var el = new(tree.Element)('&', null, 0);
+            var selectors = [new(tree.Selector)([el])];
+            result = new(tree.Ruleset)(selectors, env.mediaBlocks);
+            result.multiMedia = true;
+        }
+
+        delete env.mediaBlocks;
+        delete env.mediaPath;
+
+        return result;
+    },
+    evalNested: function (env) {
+        var i, value,
+            path = env.mediaPath.concat([this]);
+
+        // Extract the media-query conditions separated with `,` (OR).
+        for (i = 0; i < path.length; i++) {
+            value = path[i].features instanceof tree.Value ?
+                        path[i].features.value : path[i].features;
+            path[i] = Array.isArray(value) ? value : [value];
+        }
+
+        // Trace all permutations to generate the resulting media-query.
+        //
+        // (a, b and c) with nested (d, e) ->
+        //    a and d
+        //    a and e
+        //    b and c and d
+        //    b and c and e
+        this.features = new(tree.Value)(this.permute(path).map(function (path) {
+            path = path.map(function (fragment) {
+                return fragment.toCSS ? fragment : new(tree.Anonymous)(fragment);
+            });
+
+            for(i = path.length - 1; i > 0; i--) {
+                path.splice(i, 0, new(tree.Anonymous)("and"));
+            }
+
+            return new(tree.Expression)(path);
+        }));
+
+        // Fake a tree-node that doesn't output anything.
+        return new(tree.Ruleset)([], []);
+    },
+    permute: function (arr) {
+      if (arr.length === 0) {
+          return [];
+      } else if (arr.length === 1) {
+          return arr[0];
+      } else {
+          var result = [];
+          var rest = this.permute(arr.slice(1));
+          for (var i = 0; i < rest.length; i++) {
+              for (var j = 0; j < arr[0].length; j++) {
+                  result.push([arr[0][j]].concat(rest[i]));
+              }
+          }
+          return result;
+      }
+    }
+};
+
+})(require('../tree'));