Add filtered event support to event.js.

chrome/renderer/resources/extensions/event.js

Index: chrome/renderer/resources/extensions/event.js
diff --git a/chrome/renderer/resources/extensions/event.js b/chrome/renderer/resources/extensions/event.js
index 81c465b0d83d5150c4402719784de7eb72825fda..ee7d5235e5dcf94771793252eaee988c9aa97180 100644
--- a/chrome/renderer/resources/extensions/event.js
+++ b/chrome/renderer/resources/extensions/event.js
@@ -5,6 +5,8 @@
   var eventBindingsNatives = requireNative('event_bindings');
   var AttachEvent = eventBindingsNatives.AttachEvent;
   var DetachEvent = eventBindingsNatives.DetachEvent;
+  var AttachFilteredEvent = eventBindingsNatives.AttachFilteredEvent;
+  var DetachFilteredEvent = eventBindingsNatives.DetachFilteredEvent;
 
   var chromeHidden = requireNative('chrome_hidden').GetChromeHidden();
 
@@ -46,6 +48,83 @@
     };
   })();
 
+  // Handles adding/removing/dispatching listeners for unfiltered events.
+  var UnfilteredAttachmentStrategy = function(event) {
+    this.event_ = event;
+    this.eventName_ = event.eventName_;

[Matt Perry, 2012/05/16 20:45:00]

why bother caching eventName_? can't you access it through event_?

[koz (OOO until 15th September), 2012/05/18 04:50:07]

Done.

+  };
+
+  UnfilteredAttachmentStrategy.prototype.onAddedListener =
+      function(listener) {
+    // Only attach / detach on the first / last listener removed.
+    if (this.event_.listeners_.length > 1)
+      return;
+    AttachEvent(this.eventName_);
+    allAttachedEvents[allAttachedEvents.length] = this.event_;
+    if (!this.eventName_)
+      return;
+
+    if (attachedNamedEvents[this.eventName_]) {
+      throw new Error("chrome.Event '" + this.eventName_ +
+                      "' is already attached.");
+    }
+
+    attachedNamedEvents[this.eventName_] = this.event_;
+  };
+
+  UnfilteredAttachmentStrategy.prototype.onRemovedListener =
+      function(listener) {
+    if (this.event_.listeners_.length == 0)
+      this.detach(true);
+  };
+
+  UnfilteredAttachmentStrategy.prototype.detach =
+      function(manual) {
+    var i = allAttachedEvents.indexOf(this.event_);
+    if (i >= 0)
+      delete allAttachedEvents[i];
+    DetachEvent(this.eventName_, manual);
+    if (!this.eventName_)
+      return;
+
+    if (!attachedNamedEvents[this.eventName_]) {
+      throw new Error("chrome.Event '" + this.eventName_ +
+                      "' is not attached.");
+    }
+
+    delete attachedNamedEvents[this.eventName_];
+  };
+
+  var FilteredAttachmentStrategy = function(event) {
+    this.event_ = event;
+    this.eventName_ = event.eventName_;
+    this.listenerMap_ = {};
+  };
+
+  FilteredAttachmentStrategy.prototype.onAddedListener = function(listener) {
+    var id = AttachFilteredEvent(this.eventName_, listener.filters || {});
+    listener.id = id;
+    this.listenerMap_[id] = listener;
+  };
+
+  FilteredAttachmentStrategy.prototype.onRemovedListener = function(listener) {
+    this.detachListener(listener, true);
+  }
+
+  FilteredAttachmentStrategy.prototype.detachListener =
+      function(listener, manual) {
+    if (listener.id == undefined)
+      throw new Error("listener.id undefined - '" + listener + "'");
+    var id = listener.id;
+    delete this.listenerMap_[id];
+    DetachFilteredEvent(id, manual);
+  };
+
+  FilteredAttachmentStrategy.prototype.detach = function(manual) {
+    for (var i in this.listenerMap_)
+      this.detachListener(this.listenerMap_[i], manual);
+  };
+
   // Event object.  If opt_eventName is provided, this object represents
   // the unique instance of that named event, and dispatching an event
   // with that name will route through this object's listeners. Note that
@@ -63,11 +142,20 @@
     this.eventName_ = opt_eventName;
     this.listeners_ = [];
     this.eventOptions_ = opt_eventOptions ||
-        {"supportsListeners": true, "supportsRules": false};
+        {supportsListeners: true,
+         supportsRules: false,
+         supportsFilters: false,
+        };
 
     if (this.eventOptions_.supportsRules && !opt_eventName)
       throw new Error("Events that support rules require an event name.");
 
+    if (this.eventOptions_.supportsFilters) {
+      this.attachmentStrategy_ = new FilteredAttachmentStrategy(this);
+    } else {
+      this.attachmentStrategy_ = new UnfilteredAttachmentStrategy(this);
+    }
+
     // Validate event parameters if we are in debug.
     if (opt_argSchemas &&
         chromeHidden.validateCallbacks &&
@@ -136,13 +224,18 @@
   };
 
   // Registers a callback to be called when this event is dispatched.
-  chrome.Event.prototype.addListener = function(cb) {
+  chrome.Event.prototype.addListener = function(cb, filters) {
     if (!this.eventOptions_.supportsListeners)
       throw new Error("This event does not support listeners.");
-    if (this.listeners_.length == 0) {
-      this.attach_();
+    if (filters) {
+      if (!this.eventOptions_.supportsFilters)
+        throw new Error("This event does not support filters.");
+      if (filters.url && !(filters.url instanceof Array))
+        throw new Error("filter.url should be an array");
     }
-    this.listeners_.push(cb);
+    var listener = {callback: cb, filters: filters};
+    this.listeners_.push(listener);
+    this.attachmentStrategy_.onAddedListener(listener);
   };
 
   // Unregisters a callback.
@@ -154,10 +247,9 @@
       return;
     }
 
+    var removedListener = this.listeners_[idx];
     this.listeners_.splice(idx, 1);
-    if (this.listeners_.length == 0) {
-      this.detach_(true);
-    }
+    this.attachmentStrategy_.onRemovedListener(removedListener);
   };
 
   // Test if the given callback is registered for this event.
@@ -178,7 +270,7 @@
   // found.
   chrome.Event.prototype.findListener_ = function(cb) {
     for (var i = 0; i < this.listeners_.length; i++) {
-      if (this.listeners_[i] == cb) {
+      if (this.listeners_[i].callback == cb) {
         return i;
       }
     }
@@ -199,7 +291,7 @@
     var results = [];
     for (var i = 0; i < this.listeners_.length; i++) {
       try {
-        var result = this.listeners_[i].apply(null, args);
+        var result = this.listeners_[i].callback.apply(null, args);
         if (result !== undefined)
           results.push(result);
       } catch (e) {
@@ -211,43 +303,9 @@
       return {results: results};
   };
 
-  // Attaches this event object to its name.  Only one object can have a given
-  // name.
-  chrome.Event.prototype.attach_ = function() {
-    AttachEvent(this.eventName_);
-    allAttachedEvents[allAttachedEvents.length] = this;
-    if (!this.eventName_)
-      return;
-
-    if (attachedNamedEvents[this.eventName_]) {
-      throw new Error("chrome.Event '" + this.eventName_ +
-                      "' is already attached.");
-    }
-
-    attachedNamedEvents[this.eventName_] = this;
-  };
-
   // Detaches this event object from its name.
-  chrome.Event.prototype.detach_ = function(manual) {
-    var i = allAttachedEvents.indexOf(this);
-    if (i >= 0)
-      delete allAttachedEvents[i];
-    DetachEvent(this.eventName_, manual);
-    if (!this.eventName_)
-      return;
-
-    if (!attachedNamedEvents[this.eventName_]) {
-      throw new Error("chrome.Event '" + this.eventName_ +
-                      "' is not attached.");
-    }
-
-    delete attachedNamedEvents[this.eventName_];
-  };
-
-  chrome.Event.prototype.destroy_ = function() {
-    this.listeners_ = [];
-    this.validate_ = [];
-    this.detach_(false);
+  chrome.Event.prototype.detach = function() {

[Matt Perry, 2012/05/16 20:45:00]

did you mean to make this a "public" method? when would an extension want to
call event.detach()?

[koz (OOO until 15th September), 2012/05/18 04:50:07]

Done.

+    this.attachmentStrategy_.detach(false);
   };
 
   // Gets the declarative API object, or undefined if this extension doesn't
@@ -305,7 +363,7 @@
     for (var i = 0; i < allAttachedEvents.length; ++i) {
       var event = allAttachedEvents[i];
       if (event)
-        event.detach_(false);
+        event.detach();
     }
   };