electron/shell/common/node_bindings_win.cc

57 строки
1.7 KiB
C++

// Copyright (c) 2013 GitHub, Inc.
// Use of this source code is governed by the MIT license that can be
// found in the LICENSE file.
#include "shell/common/node_bindings_win.h"
#include <windows.h>
#include "base/system/sys_info.h"
namespace electron {
NodeBindingsWin::NodeBindingsWin(BrowserEnvironment browser_env)
: NodeBindings(browser_env) {
auto* const event_loop = uv_loop();
// on single-core the io comp port NumberOfConcurrentThreads needs to be 2
// to avoid cpu pegging likely caused by a busy loop in PollEvents
if (base::SysInfo::NumberOfProcessors() == 1) {
// the expectation is the event_loop has just been initialized
// which makes iocp replacement safe
CHECK_EQ(0u, event_loop->active_handles);
CHECK_EQ(0u, event_loop->active_reqs.count);
if (event_loop->iocp && event_loop->iocp != INVALID_HANDLE_VALUE)
CloseHandle(event_loop->iocp);
event_loop->iocp =
CreateIoCompletionPort(INVALID_HANDLE_VALUE, nullptr, 0, 2);
}
}
void NodeBindingsWin::PollEvents() {
auto* const event_loop = uv_loop();
// If there are other kinds of events pending, uv_backend_timeout will
// instruct us not to wait.
DWORD bytes, timeout;
ULONG_PTR key;
OVERLAPPED* overlapped;
timeout = uv_backend_timeout(event_loop);
GetQueuedCompletionStatus(event_loop->iocp, &bytes, &key, &overlapped,
timeout);
// Give the event back so libuv can deal with it.
if (overlapped != nullptr)
PostQueuedCompletionStatus(event_loop->iocp, bytes, key, overlapped);
}
// static
std::unique_ptr<NodeBindings> NodeBindings::Create(BrowserEnvironment env) {
return std::make_unique<NodeBindingsWin>(env);
}
} // namespace electron