Filtered events.

chrome/renderer/extensions/event_bindings.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/renderer/extensions/event_bindings.h"
 
 #include <vector>
 
+#include "base/bind.h"
 #include "base/basictypes.h"
 #include "base/lazy_instance.h"
+#include "base/memory/scoped_ptr.h"
 #include "base/message_loop.h"
 #include "chrome/common/extensions/extension_messages.h"
 #include "chrome/common/extensions/extension_set.h"
+#include "chrome/common/extensions/event_filter.h"
+#include "chrome/common/extensions/value_counter.h"
 #include "chrome/common/url_constants.h"
 #include "chrome/common/view_type.h"
 #include "chrome/renderer/extensions/chrome_v8_context.h"
 #include "chrome/renderer/extensions/chrome_v8_context_set.h"
 #include "chrome/renderer/extensions/chrome_v8_extension.h"
 #include "chrome/renderer/extensions/event_bindings.h"
 #include "chrome/renderer/extensions/extension_dispatcher.h"
 #include "chrome/renderer/extensions/extension_helper.h"
 #include "chrome/renderer/extensions/user_script_slave.h"
 #include "content/public/renderer/render_thread.h"
+#include "content/public/renderer/v8_value_converter.h"
 #include "googleurl/src/gurl.h"
 #include "grit/renderer_resources.h"
 #include "third_party/WebKit/Source/WebKit/chromium/public/WebDocument.h"
 #include "third_party/WebKit/Source/WebKit/chromium/public/WebFrame.h"
 #include "third_party/WebKit/Source/WebKit/chromium/public/WebSecurityOrigin.h"
 #include "third_party/WebKit/Source/WebKit/chromium/public/platform/WebURL.h"
 #include "third_party/WebKit/Source/WebKit/chromium/public/platform/WebURLRequest.h"
 #include "third_party/WebKit/Source/WebKit/chromium/public/WebView.h"
 #include "v8/include/v8.h"
 
 using WebKit::WebFrame;
 using WebKit::WebSecurityOrigin;
 using WebKit::WebURL;
 using content::RenderThread;
 using extensions::Extension;
 
 namespace {
 
 // A map of event names to the number of contexts listening to that event.
 // We notify the browser about event listeners when we transition between 0
 // and 1.
 typedef std::map<std::string, int> EventListenerCounts;
 
 // A map of extension IDs to listener counts for that extension.
 base::LazyInstance<std::map<std::string, EventListenerCounts> >
     g_listener_counts = LAZY_INSTANCE_INITIALIZER;
 
+// A map of event names to a (filter -> count) map. The map is used to keep
+// track of which filters are in effect for which events.
+// We notify the browser about filtered event listeners when we transition
+// between 0 and 1.
+typedef std::map<std::string, linked_ptr<extensions::ValueCounter> >
+    FilteredEventListenerCounts;
+
+// A map of extension IDs to filtered listener counts for that extension.
+base::LazyInstance<std::map<std::string, FilteredEventListenerCounts> >
+    g_filtered_listener_counts = LAZY_INSTANCE_INITIALIZER;
+
 // TODO(koz): Merge this into EventBindings.
 class ExtensionImpl : public ChromeV8Extension {
  public:
 
-  explicit ExtensionImpl(ExtensionDispatcher* dispatcher)
-      : ChromeV8Extension(dispatcher) {
-    RouteStaticFunction("AttachEvent", &AttachEvent);
-    RouteStaticFunction("DetachEvent", &DetachEvent);
+  ExtensionImpl(ExtensionDispatcher* dispatcher,
+      extensions::EventFilter* event_filter)
+      : ChromeV8Extension(dispatcher),
+        event_filter_(event_filter) {
+    RouteFunction("AttachEvent",
+        base::Bind(&ExtensionImpl::AttachEvent,
+                   base::Unretained(this)));
+    RouteFunction("DetachEvent",
+        base::Bind(&ExtensionImpl::DetachEvent,
+                   base::Unretained(this)));
+    RouteFunction("AttachFilteredEvent",
+        base::Bind(&ExtensionImpl::AttachFilteredEvent,
+                   base::Unretained(this)));
+    RouteFunction("DetachFilteredEvent",
+        base::Bind(&ExtensionImpl::DetachFilteredEvent,
+                   base::Unretained(this)));
+    RouteFunction("MatchAgainstEventFilter",
+        base::Bind(&ExtensionImpl::MatchAgainstEventFilter,
+                   base::Unretained(this)));
   }
   ~ExtensionImpl() {}
 
   // Attach an event name to an object.
-  static v8::Handle<v8::Value> AttachEvent(const v8::Arguments& args) {
+  v8::Handle<v8::Value> AttachEvent(const v8::Arguments& args) {
     DCHECK(args.Length() == 1);
     // TODO(erikkay) should enforce that event name is a string in the bindings
     DCHECK(args[0]->IsString() || args[0]->IsUndefined());
 
     if (args[0]->IsString()) {
-      ExtensionImpl* self = GetFromArguments<ExtensionImpl>(args);
+      std::string event_name = *v8::String::AsciiValue(args[0]->ToString());
       const ChromeV8ContextSet& context_set =
-          self->extension_dispatcher()->v8_context_set();
+          extension_dispatcher()->v8_context_set();
       ChromeV8Context* context = context_set.GetCurrent();
       CHECK(context);
-      std::string event_name(*v8::String::AsciiValue(args[0]));
 
-      ExtensionDispatcher* extension_dispatcher = self->extension_dispatcher();
-      if (!extension_dispatcher->CheckCurrentContextAccessToExtensionAPI(
+      if (!extension_dispatcher()->CheckCurrentContextAccessToExtensionAPI(
               event_name))
         return v8::Undefined();
 
       std::string extension_id = context->GetExtensionID();
       EventListenerCounts& listener_counts =
           g_listener_counts.Get()[extension_id];
       if (++listener_counts[event_name] == 1) {
         content::RenderThread::Get()->Send(
             new ExtensionHostMsg_AddListener(extension_id, event_name));
       }
 
       // This is called the first time the page has added a listener. Since
       // the background page is the only lazy page, we know this is the first
       // time this listener has been registered.
-      if (self->IsLazyBackgroundPage(context->extension())) {
+      if (IsLazyBackgroundPage(context->extension())) {
         content::RenderThread::Get()->Send(
             new ExtensionHostMsg_AddLazyListener(extension_id, event_name));
       }
     }
-
     return v8::Undefined();
   }
 
-  static v8::Handle<v8::Value> DetachEvent(const v8::Arguments& args) {
+  v8::Handle<v8::Value> DetachEvent(const v8::Arguments& args) {
     DCHECK(args.Length() == 2);
     // TODO(erikkay) should enforce that event name is a string in the bindings
     DCHECK(args[0]->IsString() || args[0]->IsUndefined());
 
     if (args[0]->IsString() && args[1]->IsBoolean()) {
-      ExtensionImpl* self = GetFromArguments<ExtensionImpl>(args);
+      std::string event_name = *v8::String::AsciiValue(args[0]->ToString());
+      bool is_manual = args[1]->BooleanValue();
+
       const ChromeV8ContextSet& context_set =
-          self->extension_dispatcher()->v8_context_set();
+          extension_dispatcher()->v8_context_set();
       ChromeV8Context* context = context_set.GetCurrent();
       if (!context)
         return v8::Undefined();
 
       std::string extension_id = context->GetExtensionID();
       EventListenerCounts& listener_counts =
           g_listener_counts.Get()[extension_id];
-      std::string event_name(*v8::String::AsciiValue(args[0]));
-      bool is_manual = args[1]->BooleanValue();
 
       if (--listener_counts[event_name] == 0) {
         content::RenderThread::Get()->Send(
             new ExtensionHostMsg_RemoveListener(extension_id, event_name));
       }
 
       // DetachEvent is called when the last listener for the context is
       // removed. If the context is the background page, and it removes the
       // last listener manually, then we assume that it is no longer interested
       // in being awakened for this event.
-      if (is_manual && self->IsLazyBackgroundPage(context->extension())) {
+      if (is_manual && IsLazyBackgroundPage(context->extension())) {
         content::RenderThread::Get()->Send(
             new ExtensionHostMsg_RemoveLazyListener(extension_id, event_name));
       }
     }
+    return v8::Undefined();
+  }
+
+  // MatcherID AttachFilteredEvent(string event_name, object filter)
+  // event_name - Name of the event to attach.
+  // filter - Which instances of the named event are we interested in.
+  // returns the id assigned to the listener, which will be returned from calls
+  // to MatchAgainstEventFilter where this listener matches.
+  v8::Handle<v8::Value> AttachFilteredEvent(const v8::Arguments& args) {
+    DCHECK_EQ(2, args.Length());
+    DCHECK(args[0]->IsString());
+    DCHECK(args[1]->IsObject());
+
+    const ChromeV8ContextSet& context_set =
+        extension_dispatcher()->v8_context_set();
+    ChromeV8Context* context = context_set.GetCurrent();
+    DCHECK(context);
+    if (!context)
+      return v8::Integer::New(-1);
+
+    std::string event_name = *v8::String::AsciiValue(args[0]);
+    // This method throws an exception if it returns false.
+    if (!extension_dispatcher()->CheckCurrentContextAccessToExtensionAPI(
+            event_name))
+      return v8::Undefined();
+
+    std::string extension_id = context->GetExtensionID();
+    if (extension_id.empty())
+      return v8::Integer::New(-1);
+
+    scoped_ptr<base::DictionaryValue> filter;
+    scoped_ptr<content::V8ValueConverter> converter(
+        content::V8ValueConverter::create());
+
+    base::DictionaryValue* filter_dict = NULL;
+    base::Value* filter_value = converter->FromV8Value(args[1]->ToObject(),
+        v8::Context::GetCurrent());
+    if (!filter_value->GetAsDictionary(&filter_dict)) {
+      delete filter_value;

[battre, 2012/06/20 09:50:46]

I think filter_value is still lost if you don't run into this branch. My
proposal would be to just make filter_value a scoped_ptr.

[koz (OOO until 15th September), 2012/06/21 02:23:11]

Is it? I thought that filter_value->GetAsDictionary(&filter_dict) just sets
filter_dict to a new pointer to filter_value with a different type.  Below I
have "filter.reset(filter_dict)" which takes care of ownership of filter_dict
and therefore filter_value.

[battre, 2012/06/21 05:35:16]

ah, you are right. I missed the "As" in GetAsDictionary.

+      return v8::Integer::New(-1);
+    }
+
+    filter.reset(filter_dict);
+    int id = event_filter_->AddEventMatcher(event_name, ParseEventMatcher(
+        filter.get()));
+
+    // Only send IPCs the first time a filter gets added.
+    if (AddFilter(event_name, extension_id, filter.get())) {
+      bool lazy = IsLazyBackgroundPage(context->extension());
+      content::RenderThread::Get()->Send(
+          new ExtensionHostMsg_AddFilteredListener(extension_id, event_name,
+                                                   *filter, lazy));
+    }
+
+    return v8::Integer::New(id);
+  }
+
+  // Add a filter to |event_name| in |extension_id|, returning true if it
+  // was the first filter for that event in that extension.
+  bool AddFilter(const std::string& event_name,
+                 const std::string& extension_id,
+                 base::DictionaryValue* filter) {
+    FilteredEventListenerCounts& counts =
+        g_filtered_listener_counts.Get()[extension_id];
+    FilteredEventListenerCounts::iterator it = counts.find(event_name);
+    if (it == counts.end())
+      counts[event_name].reset(new extensions::ValueCounter);
+
+    int result = counts[event_name]->Add(*filter);
+    return 1 == result;
+  }
+
+  // Remove a filter from |event_name| in |extension_id|, returning true if it
+  // was the last filter for that event in that extension.
+  bool RemoveFilter(const std::string& event_name,
+                    const std::string& extension_id,
+                    base::DictionaryValue* filter) {
+    FilteredEventListenerCounts& counts =
+        g_filtered_listener_counts.Get()[extension_id];
+    FilteredEventListenerCounts::iterator it = counts.find(event_name);
+    if (it == counts.end())
+      return false;
+    return 0 == it->second->Remove(*filter);
+  }
+
+  // void DetachFilteredEvent(int id, bool manual)
+  // id     - Id of the event to detach.
+  // manual - false if this is part of the extension unload process where all
+  //          listeners are automatically detached.
+  v8::Handle<v8::Value> DetachFilteredEvent(const v8::Arguments& args) {
+    DCHECK_EQ(2, args.Length());
+    DCHECK(args[0]->IsInt32());
+    DCHECK(args[1]->IsBoolean());
+    bool is_manual = args[1]->BooleanValue();
+    const ChromeV8ContextSet& context_set =
+        extension_dispatcher()->v8_context_set();
+    ChromeV8Context* context = context_set.GetCurrent();
+    if (!context)
+      return v8::Undefined();
+
+    std::string extension_id = context->GetExtensionID();
+    if (extension_id.empty())
+      return v8::Undefined();
+
+    int matcher_id = args[0]->Int32Value();
+    extensions::EventMatcher* event_matcher =
+        event_filter_->GetEventMatcher(matcher_id);
+
+    const std::string& event_name = event_filter_->GetEventName(matcher_id);
+
+    // Only send IPCs the last time a filter gets removed.
+    if (RemoveFilter(event_name, extension_id, event_matcher->value())) {
+      bool lazy = is_manual && IsLazyBackgroundPage(context->extension());
+      content::RenderThread::Get()->Send(
+          new ExtensionHostMsg_RemoveFilteredListener(extension_id, event_name,
+                                                      *event_matcher->value(),
+                                                      lazy));
+    }
+
+    event_filter_->RemoveEventMatcher(matcher_id);
 
     return v8::Undefined();
   }
 
+  v8::Handle<v8::Value> MatchAgainstEventFilter(const v8::Arguments& args) {
+    typedef std::set<extensions::EventFilter::MatcherID> MatcherIDs;
+
+    std::string event_name = *v8::String::AsciiValue(args[0]->ToString());
+    extensions::EventFilteringInfo info = ParseFromObject(args[1]->ToObject());
+    MatcherIDs matched_event_filters = event_filter_->MatchEvent(
+        event_name, info);
+    v8::Handle<v8::Array> array(v8::Array::New(matched_event_filters.size()));
+    int i = 0;
+    for (MatcherIDs::iterator it = matched_event_filters.begin();
+         it != matched_event_filters.end(); ++it) {
+      array->Set(v8::Integer::New(i++), v8::Integer::New(*it));
+    }
+    return array;
+  }
+
+  extensions::EventFilteringInfo ParseFromObject(
+      v8::Handle<v8::Object> object) {
+    extensions::EventFilteringInfo info;
+    v8::Handle<v8::String> url(v8::String::New("url"));
+    if (object->Has(url)) {
+      v8::Handle<v8::Value> url_value(object->Get(url));
+      info.SetURL(GURL(*v8::String::AsciiValue(url_value)));
+    }
+    return info;
+  }
+
  private:
-
+  extensions::EventFilter* event_filter_;
   bool IsLazyBackgroundPage(const Extension* extension) {
     content::RenderView* render_view = GetCurrentRenderView();
     if (!render_view)
       return false;
 
     ExtensionHelper* helper = ExtensionHelper::Get(render_view);
     return (extension && extension->has_lazy_background_page() &&
             helper->view_type() == chrome::VIEW_TYPE_EXTENSION_BACKGROUND_PAGE);
   }
+
+  scoped_ptr<extensions::EventMatcher> ParseEventMatcher(
+      base::DictionaryValue* filter_dict) {
+    return scoped_ptr<extensions::EventMatcher>(new extensions::EventMatcher(
+        scoped_ptr<base::DictionaryValue>(filter_dict->DeepCopy())));
+  }
 };
 
 }  // namespace
 
-ChromeV8Extension* EventBindings::Get(ExtensionDispatcher* dispatcher) {
-  return new ExtensionImpl(dispatcher);
+// static
+ChromeV8Extension* EventBindings::Get(ExtensionDispatcher* dispatcher,
+    extensions::EventFilter* event_filter) {
+  return new ExtensionImpl(dispatcher, event_filter);
 }