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