electron/common/node_bindings_mac.mm
Cheng Zhao 855b42551d Improve the way to integrate libuv.
Now we poll libuv's events in embed thread by adding main loop's backend
fd to a new kqueue fd, instead of directly polling on main loop's
backend fd. In this way we can avoid dealing with one shot events
overselves.
2013-04-19 21:21:04 +08:00

129 lines
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// Copyright (c) 2013 GitHub, Inc. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "common/node_bindings_mac.h"
#include <sys/sysctl.h>
#include <sys/time.h>
#include <sys/types.h>
#include "base/message_loop.h"
#include "content/public/browser/browser_thread.h"
#include "vendor/node/src/node.h"
#include "vendor/node/src/node_internals.h"
using content::BrowserThread;
namespace atom {
namespace {
void UvNoOp(uv_async_t* handle, int status) {
}
}
NodeBindingsMac::NodeBindingsMac(bool is_browser)
: NodeBindings(is_browser),
loop_(uv_default_loop()),
kqueue_(kqueue()),
embed_closed_(false) {
}
NodeBindingsMac::~NodeBindingsMac() {
// Clear uv.
embed_closed_ = true;
uv_thread_join(&embed_thread_);
uv_sem_destroy(&embed_sem_);
}
void NodeBindingsMac::PrepareMessageLoop() {
DCHECK(!is_browser_ || BrowserThread::CurrentlyOn(BrowserThread::UI));
// Add dummy handle for libuv, otherwise libuv would quit when there is
// nothing to do.
uv_async_init(loop_, &dummy_uv_handle_, UvNoOp);
// Start worker that will interrupt main loop when having uv events.
uv_sem_init(&embed_sem_, 0);
uv_thread_create(&embed_thread_, EmbedThreadRunner, this);
}
void NodeBindingsMac::RunMessageLoop() {
DCHECK(!is_browser_ || BrowserThread::CurrentlyOn(BrowserThread::UI));
loop_->data = this;
loop_->on_watcher_queue_updated = OnWatcherQueueChanged;
// Run uv loop for once to give the uv__io_poll a chance to add all events.
UvRunOnce();
}
void NodeBindingsMac::UvRunOnce() {
DCHECK(!is_browser_ || BrowserThread::CurrentlyOn(BrowserThread::UI));
// Enter node context while dealing with uv events.
v8::Context::Scope context_scope(node::g_context);
// Deal with uv events.
int r = uv_run(loop_, (uv_run_mode)(UV_RUN_ONCE | UV_RUN_NOWAIT));
if (r == 0 || loop_->stop_flag != 0)
MessageLoop::current()->QuitWhenIdle(); // Quit from uv.
// Tell the worker thread to continue polling.
uv_sem_post(&embed_sem_);
}
void NodeBindingsMac::EmbedThreadRunner(void *arg) {
NodeBindingsMac* self = static_cast<NodeBindingsMac*>(arg);
uv_loop_t* loop = self->loop_;
// Add uv's backend fd to kqueue.
struct kevent ev;
EV_SET(&ev, uv_backend_fd(loop), EVFILT_READ, EV_ADD | EV_ENABLE, 0, 0, 0);
kevent(self->kqueue_, &ev, 1, NULL, 0, NULL);
while (!self->embed_closed_) {
// Wait for the main loop to deal with events.
uv_sem_wait(&self->embed_sem_);
struct timespec spec;
int timeout = uv_backend_timeout(loop);
if (timeout != -1) {
spec.tv_sec = timeout / 1000;
spec.tv_nsec = (timeout % 1000) * 1000000;
}
// Wait for new libuv events.
int r;
do {
r = ::kevent(self->kqueue_, NULL, 0, &ev, 1,
timeout == -1 ? NULL : &spec);
} while (r == -1 && errno == EINTR);
// Deal with event in main thread.
dispatch_async(dispatch_get_main_queue(), ^{
self->UvRunOnce();
});
}
}
// static
void NodeBindingsMac::OnWatcherQueueChanged(uv_loop_t* loop) {
NodeBindingsMac* self = static_cast<NodeBindingsMac*>(loop->data);
DCHECK(!self->is_browser_ || BrowserThread::CurrentlyOn(BrowserThread::UI));
// We need to break the io polling in the kqueue thread when loop's watcher
// queue changes, otherwise new events cannot be notified.
uv_async_send(&self->dummy_uv_handle_);
}
// static
NodeBindings* NodeBindings::Create(bool is_browser) {
return new NodeBindingsMac(is_browser);
}
} // namespace atom