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// Copyright (c) 2009 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 "base/basictypes.h"
#include "base/singleton.h"
#include "chrome/common/render_messages.h"
#include "chrome/renderer/extensions/bindings_utils.h"
#include "chrome/renderer/extensions/event_bindings.h"
#include "chrome/renderer/js_only_v8_extensions.h"
#include "chrome/renderer/render_thread.h"
#include "grit/renderer_resources.h"
namespace {
// Keep a local cache of RenderThread so that we can mock it out for unit tests.
static RenderThreadBase* render_thread = NULL;
static RenderThreadBase* GetRenderThread() {
return render_thread ? render_thread : RenderThread::current();
}
// Keep a list of contexts that have registered themselves with us. This lets
// us know where to dispatch events when we receive them.
typedef std::list< v8::Persistent<v8::Context> > ContextList;
struct ExtensionData {
ContextList contexts;
std::map<std::string, int> listener_count;
};
ContextList& GetRegisteredContexts() {
return Singleton<ExtensionData>::get()->contexts;
}
int EventIncrementListenerCount(const std::string& event_name) {
ExtensionData *data = Singleton<ExtensionData>::get();
return ++(data->listener_count[event_name]);
}
int EventDecrementListenerCount(const std::string& event_name) {
ExtensionData *data = Singleton<ExtensionData>::get();
return --(data->listener_count[event_name]);
}
const char* kExtensionDeps[] = { JsonJsV8Extension::kName };
const char* kContextAttachCount = "chromium.attachCount";
class ExtensionImpl : public v8::Extension {
public:
ExtensionImpl()
: v8::Extension(EventBindings::kName,
GetStringResource<IDR_EVENT_BINDINGS_JS>(),
arraysize(kExtensionDeps), kExtensionDeps) {
}
~ExtensionImpl() {}
virtual v8::Handle<v8::FunctionTemplate> GetNativeFunction(
v8::Handle<v8::String> name) {
if (name->Equals(v8::String::New("AttachEvent"))) {
return v8::FunctionTemplate::New(AttachEvent);
} else if (name->Equals(v8::String::New("DetachEvent"))) {
return v8::FunctionTemplate::New(DetachEvent);
}
return v8::Handle<v8::FunctionTemplate>();
}
// Attach an event name to an object.
static 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());
v8::Persistent<v8::Context> context =
v8::Persistent<v8::Context>::New(v8::Context::GetCurrent());
v8::Local<v8::Object> global = context->Global();
// Remember how many times this context has been attached, so we can
// register the context on first attach and unregister on last detach.
v8::Local<v8::Value> attach_count = global->GetHiddenValue(
v8::String::New(kContextAttachCount));
int32_t account_count_value =
(!attach_count.IsEmpty() && attach_count->IsNumber()) ?
attach_count->Int32Value() : 0;
if (account_count_value == 0) {
// First time attaching.
GetRegisteredContexts().push_back(context);
context.MakeWeak(NULL, WeakContextCallback);
}
global->SetHiddenValue(
v8::String::New(kContextAttachCount),
v8::Integer::New(account_count_value + 1));
if (args[0]->IsString()) {
std::string event_name(*v8::String::AsciiValue(args[0]));
if (EventIncrementListenerCount(event_name) == 1) {
GetRenderThread()->Send(
new ViewHostMsg_ExtensionAddListener(event_name));
}
}
return v8::Undefined();
}
static v8::Handle<v8::Value> DetachEvent(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());
v8::Local<v8::Context> context = v8::Context::GetCurrent();
v8::Local<v8::Object> global = context->Global();
v8::Local<v8::Value> attach_count = global->GetHiddenValue(
v8::String::New(kContextAttachCount));
DCHECK(!attach_count.IsEmpty() && attach_count->IsNumber());
int32_t account_count_value = attach_count->Int32Value();
DCHECK(account_count_value > 0);
if (account_count_value == 1) {
// Clean up after last detach.
UnregisterContext(context);
}
global->SetHiddenValue(
v8::String::New(kContextAttachCount),
v8::Integer::New(account_count_value - 1));
if (args[0]->IsString()) {
std::string event_name(*v8::String::AsciiValue(args[0]));
if (EventDecrementListenerCount(event_name) == 0) {
GetRenderThread()->Send(
new ViewHostMsg_ExtensionRemoveListener(event_name));
}
}
return v8::Undefined();
}
// Called when a registered context is garbage collected.
static void UnregisterContext(v8::Handle<void> context) {
ContextList& contexts = GetRegisteredContexts();
ContextList::iterator it = std::find(contexts.begin(), contexts.end(),
context);
if (it == contexts.end()) {
NOTREACHED();
return;
}
it->Dispose();
it->Clear();
contexts.erase(it);
}
// Called when a registered context is garbage collected.
static void WeakContextCallback(v8::Persistent<v8::Value> obj, void*) {
UnregisterContext(obj);
}
};
} // namespace
const char* EventBindings::kName = "chrome/EventBindings";
v8::Extension* EventBindings::Get() {
return new ExtensionImpl();
}
// static
void EventBindings::SetRenderThread(RenderThreadBase* thread) {
render_thread = thread;
}
void EventBindings::CallFunction(const std::string& function_name,
int argc, v8::Handle<v8::Value>* argv) {
for (ContextList::iterator it = GetRegisteredContexts().begin();
it != GetRegisteredContexts().end(); ++it) {
DCHECK(!it->IsEmpty());
v8::Context::Scope context_scope(*it);
v8::Local<v8::Object> global = (*it)->Global();
v8::Local<v8::Script> script = v8::Script::Compile(
v8::String::New(function_name.c_str()));
v8::Local<v8::Value> function_obj = script->Run();
if (!function_obj->IsFunction())
continue;
v8::Local<v8::Function> function =
v8::Local<v8::Function>::Cast(function_obj);
if (!function.IsEmpty())
function->Call(v8::Object::New(), argc, argv);
}
}
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