Merge pull request #476 from ochameau/bug/769006-fix-MutationObserver

Bug: 769006: Ensure that MutationObserver works in content scripts. r=@Gozala
mozilla · Jul 8, 2012 · 7e78b8a · 7e78b8a
2 parents 983a9ef + 5d86f98
commit 7e78b8a
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diff --git a/packages/api-utils/lib/content/content-proxy.js b/packages/api-utils/lib/content/content-proxy.js
@@ -542,7 +542,7 @@ const xRayWrappersMissFixes = [
   // Trap access to form["node name"]
   // http://mxr.mozilla.org/mozilla-central/source/dom/base/nsDOMClassInfo.cpp#9477
   function (obj, name) {
-    if (typeof obj == "object" && obj.tagName == "FORM") {
+    if (typeof obj == "object" && "tagName" in obj && obj.tagName == "FORM") {
       let match = obj.wrappedJSObject[name];
       let nodes = obj.ownerDocument.getElementsByName(name);
       for (let i = 0, l = nodes.length; i < l; i++) {
@@ -660,6 +660,33 @@ const xRayWrappersMethodsFixes = {
     };
 
     return getProxyForFunction(f, NativeFunctionWrapper(f));
+  },
+
+  // Bug 769006: nsIDOMMutationObserver.observe fails with proxy as options
+  // attributes
+  observe: function observe(obj) {
+    // Ensure that we are on a DOMMutation object
+    try {
+      // nsIDOMMutationObserver starts with FF14
+      if ("nsIDOMMutationObserver" in Ci)
+        obj.QueryInterface(Ci.nsIDOMMutationObserver);
+      else
+        return null;
+    }
+    catch(e) {
+      return null;
+    }
+    return function nsIDOMMutationObserverObserveFix(target, options) {
+      // Gets native/unwrapped this
+      let self = this && typeof this.valueOf == "function" ?
+                 this.valueOf(UNWRAP_ACCESS_KEY) : this;
+      // Unwrap the xraywrapper target out of JS proxy
+      let targetXray = unwrap(target);
+      // But do not wrap `options` through ContentScriptObjectWrapper
+      let result = wrap(self.observe(targetXray, options));
+      // Finally wrap result into JS proxies
+      return wrap(result);
+    };
   }
 };
 

diff --git a/packages/api-utils/tests/test-content-proxy.js b/packages/api-utils/tests/test-content-proxy.js
@@ -808,3 +808,42 @@ exports.testCrossDomainIframe = createProxyTest("", function (helper) {
   worker.postMessage("http://localhost:" + serverPort + "/");
 
 });
+
+// Bug 769006: Ensure that MutationObserver works fine with proxies
+let html = '<a href="foo">link</a>';
+exports.testMutationObvserver = createProxyTest(html, function (helper) {
+
+  helper.createWorker(
+    'new ' + function ContentScriptScope() {
+      if (typeof MutationObserver == "undefined") {
+        assert(true, "No MutationObserver for this FF version");
+        done();
+        return;
+      }
+      let link = document.getElementsByTagName("a")[0];
+
+      // Register a Mutation observer
+      let obs = new MutationObserver(function(mutations){
+        // Ensure that mutation data are valid
+        assert(mutations.length == 1, "only one attribute mutation");
+        let mutation = mutations[0];
+        assert(mutation.type == "attributes", "check `type`");
+        assert(mutation.target == link, "check `target`");
+        assert(mutation.attributeName == "href", "check `attributeName`");
+        assert(mutation.oldValue == "foo", "check `oldValue`");
+        obs.disconnect();
+        done();
+      });
+      obs.observe(document, {
+        subtree: true,
+        attributes: true,
+        attributeOldValue: true,
+        attributeFilter: ["href"]
+      });
+
+      // Modify the DOM
+      link.setAttribute("href", "bar");
+    }
+  );
+
+});