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- // Copyright 2013 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 "base/win/message_window.h"
- #include <windows.h>
- #include <utility>
- #include "base/lazy_instance.h"
- #include "base/logging.h"
- #include "base/strings/string_util.h"
- #include "base/win/current_module.h"
- #include "base/win/wrapped_window_proc.h"
- // To avoid conflicts with the macro from the Windows SDK...
- #undef FindWindow
- const wchar_t kMessageWindowClassName[] = L"Chrome_MessageWindow";
- namespace base {
- namespace win {
- // Used along with LazyInstance to register a window class for message-only
- // windows created by MessageWindow.
- class MessageWindow::WindowClass {
- public:
- WindowClass();
- WindowClass(const WindowClass&) = delete;
- WindowClass& operator=(const WindowClass&) = delete;
- ~WindowClass();
- ATOM atom() { return atom_; }
- HINSTANCE instance() { return instance_; }
- private:
- ATOM atom_ = 0;
- HINSTANCE instance_ = CURRENT_MODULE();
- };
- static LazyInstance<MessageWindow::WindowClass>::DestructorAtExit
- g_window_class = LAZY_INSTANCE_INITIALIZER;
- MessageWindow::WindowClass::WindowClass() {
- WNDCLASSEX window_class;
- window_class.cbSize = sizeof(window_class);
- window_class.style = 0;
- window_class.lpfnWndProc = &WrappedWindowProc<WindowProc>;
- window_class.cbClsExtra = 0;
- window_class.cbWndExtra = 0;
- window_class.hInstance = instance_;
- window_class.hIcon = nullptr;
- window_class.hCursor = nullptr;
- window_class.hbrBackground = nullptr;
- window_class.lpszMenuName = nullptr;
- window_class.lpszClassName = kMessageWindowClassName;
- window_class.hIconSm = nullptr;
- atom_ = RegisterClassEx(&window_class);
- if (atom_ == 0) {
- PLOG(ERROR)
- << "Failed to register the window class for a message-only window";
- }
- }
- MessageWindow::WindowClass::~WindowClass() {
- if (atom_ != 0) {
- BOOL result = UnregisterClass(MAKEINTATOM(atom_), instance_);
- // Hitting this DCHECK usually means that some MessageWindow objects were
- // leaked. For example not calling
- // ui::Clipboard::DestroyClipboardForCurrentThread() results in a leaked
- // MessageWindow.
- DCHECK(result);
- }
- }
- MessageWindow::MessageWindow() = default;
- MessageWindow::~MessageWindow() {
- DCHECK_CALLED_ON_VALID_THREAD(thread_checker_);
- if (window_ != nullptr) {
- BOOL result = DestroyWindow(window_);
- DCHECK(result);
- }
- }
- bool MessageWindow::Create(MessageCallback message_callback) {
- return DoCreate(std::move(message_callback), nullptr);
- }
- bool MessageWindow::CreateNamed(MessageCallback message_callback,
- const std::wstring& window_name) {
- return DoCreate(std::move(message_callback), window_name.c_str());
- }
- // static
- HWND MessageWindow::FindWindow(const std::wstring& window_name) {
- return FindWindowEx(HWND_MESSAGE, nullptr, kMessageWindowClassName,
- window_name.c_str());
- }
- bool MessageWindow::DoCreate(MessageCallback message_callback,
- const wchar_t* window_name) {
- DCHECK_CALLED_ON_VALID_THREAD(thread_checker_);
- DCHECK(message_callback_.is_null());
- DCHECK(!window_);
- message_callback_ = std::move(message_callback);
- WindowClass& window_class = g_window_class.Get();
- window_ =
- CreateWindow(MAKEINTATOM(window_class.atom()), window_name, 0, 0, 0, 0, 0,
- HWND_MESSAGE, nullptr, window_class.instance(), this);
- if (!window_) {
- PLOG(ERROR) << "Failed to create a message-only window";
- return false;
- }
- return true;
- }
- // static
- LRESULT CALLBACK MessageWindow::WindowProc(HWND hwnd,
- UINT message,
- WPARAM wparam,
- LPARAM lparam) {
- MessageWindow* self =
- reinterpret_cast<MessageWindow*>(GetWindowLongPtr(hwnd, GWLP_USERDATA));
- switch (message) {
- // Set up the self before handling WM_CREATE.
- case WM_CREATE: {
- CREATESTRUCT* cs = reinterpret_cast<CREATESTRUCT*>(lparam);
- self = reinterpret_cast<MessageWindow*>(cs->lpCreateParams);
- // Make |hwnd| available to the message handler. At this point the control
- // hasn't returned from CreateWindow() yet.
- self->window_ = hwnd;
- // Store pointer to the self to the window's user data.
- SetLastError(ERROR_SUCCESS);
- LONG_PTR result = SetWindowLongPtr(hwnd, GWLP_USERDATA,
- reinterpret_cast<LONG_PTR>(self));
- CHECK(result != 0 || GetLastError() == ERROR_SUCCESS);
- break;
- }
- // Clear the pointer to stop calling the self once WM_DESTROY is
- // received.
- case WM_DESTROY: {
- SetLastError(ERROR_SUCCESS);
- LONG_PTR result = SetWindowLongPtr(hwnd, GWLP_USERDATA, NULL);
- CHECK(result != 0 || GetLastError() == ERROR_SUCCESS);
- break;
- }
- }
- // Handle the message.
- if (self) {
- LRESULT message_result;
- if (self->message_callback_.Run(message, wparam, lparam, &message_result))
- return message_result;
- }
- return DefWindowProc(hwnd, message, wparam, lparam);
- }
- } // namespace win
- } // namespace base
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