1 files changed, 82 insertions, 0 deletions
diff --git a/devtools/server/actors/media-rule.js b/devtools/server/actors/media-rule.js
new file mode 100644
index 0000000000..3c9d662ef3
--- /dev/null
+++ b/devtools/server/actors/media-rule.js
@@ -0,0 +1,82 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+"use strict";
+
+const { Cu } = require("chrome");
+const protocol = require("devtools/shared/protocol");
+const { mediaRuleSpec } = require("devtools/shared/specs/media-rule");
+const InspectorUtils = require("InspectorUtils");
+
+/**
+ * A MediaRuleActor lives on the server and provides access to properties
+ * of a DOM @media rule and emits events when it changes.
+ */
+var MediaRuleActor = protocol.ActorClassWithSpec(mediaRuleSpec, {
+  get window() {
+    return this.parentActor.window;
+  },
+
+  get document() {
+    return this.window.document;
+  },
+
+  get matches() {
+    return this.mql ? this.mql.matches : null;
+  },
+
+  initialize: function(mediaRule, parentActor) {
+    protocol.Actor.prototype.initialize.call(this, parentActor.conn);
+
+    this.rawRule = mediaRule;
+    this.parentActor = parentActor;
+    this.conn = this.parentActor.conn;
+
+    this._matchesChange = this._matchesChange.bind(this);
+
+    this.line = InspectorUtils.getRuleLine(mediaRule);
+    this.column = InspectorUtils.getRuleColumn(mediaRule);
+
+    try {
+      this.mql = this.window.matchMedia(mediaRule.media.mediaText);
+    } catch (e) {
+      // Ignored
+    }
+
+    if (this.mql) {
+      this.mql.addListener(this._matchesChange);
+    }
+  },
+
+  destroy: function() {
+    if (this.mql) {
+      // The content page may already be destroyed and mql be the dead wrapper.
+      if (!Cu.isDeadWrapper(this.mql)) {
+        this.mql.removeListener(this._matchesChange);
+      }
+      this.mql = null;
+    }
+
+    protocol.Actor.prototype.destroy.call(this);
+  },
+
+  form: function() {
+    const form = {
+      actor: this.actorID, // actorID is set when this is added to a pool
+      mediaText: this.rawRule.media.mediaText,
+      conditionText: this.rawRule.conditionText,
+      matches: this.matches,
+      line: this.line,
+      column: this.column,
+      parentStyleSheet: this.parentActor.actorID,
+    };
+
+    return form;
+  },
+
+  _matchesChange: function() {
+    this.emit("matches-change", this.matches);
+  },
+});
+exports.MediaRuleActor = MediaRuleActor;