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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 "base/lazy_instance.h"
#include "base/logging.h"
#include "base/process/memory.h"
#include "base/win/wrapped_window_proc.h"
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();
ATOM atom() { return atom_; }
HINSTANCE instance() { return instance_; }
private:
ATOM atom_;
HINSTANCE instance_;
DISALLOW_COPY_AND_ASSIGN(WindowClass);
};
static LazyInstance<MessageWindow::WindowClass> g_window_class =
LAZY_INSTANCE_INITIALIZER;
MessageWindow::WindowClass::WindowClass()
: atom_(0),
instance_(base::GetModuleFromAddress(&MessageWindow::WindowProc)) {
WNDCLASSEX window_class;
window_class.cbSize = sizeof(window_class);
window_class.style = 0;
window_class.lpfnWndProc = &base::win::WrappedWindowProc<WindowProc>;
window_class.cbClsExtra = 0;
window_class.cbWndExtra = 0;
window_class.hInstance = instance_;
window_class.hIcon = NULL;
window_class.hCursor = NULL;
window_class.hbrBackground = NULL;
window_class.lpszMenuName = NULL;
window_class.lpszClassName = kMessageWindowClassName;
window_class.hIconSm = NULL;
atom_ = RegisterClassEx(&window_class);
if (atom_ == 0) {
LOG_GETLASTERROR(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()
: window_(NULL) {
}
MessageWindow::~MessageWindow() {
DCHECK(CalledOnValidThread());
if (window_ != NULL) {
BOOL result = DestroyWindow(window_);
DCHECK(result);
}
}
bool MessageWindow::Create(const MessageCallback& message_callback) {
return DoCreate(message_callback, NULL);
}
bool MessageWindow::CreateNamed(const MessageCallback& message_callback,
const string16& window_name) {
return DoCreate(message_callback, window_name.c_str());
}
// static
HWND MessageWindow::FindWindow(const string16& window_name) {
return FindWindowEx(HWND_MESSAGE, NULL, kMessageWindowClassName,
window_name.c_str());
}
bool MessageWindow::DoCreate(const MessageCallback& message_callback,
const wchar_t* window_name) {
DCHECK(CalledOnValidThread());
DCHECK(message_callback_.is_null());
DCHECK(!window_);
message_callback_ = message_callback;
WindowClass& window_class = g_window_class.Get();
window_ = CreateWindow(MAKEINTATOM(window_class.atom()), window_name, 0, 0, 0,
0, 0, HWND_MESSAGE, 0, window_class.instance(), this);
if (!window_) {
LOG_GETLASTERROR(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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