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// Copyright 2012 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "base/win/wrapped_window_proc.h"
#include <atomic>
#include "base/check.h"
#include "base/notreached.h"
#include "base/strings/string_util.h"
namespace {
std::atomic<base::win::WinProcExceptionFilter> s_exception_filter = nullptr;
static_assert(
std::atomic<base::win::WinProcExceptionFilter>::is_always_lock_free,
"");
HMODULE GetModuleFromWndProc(WNDPROC window_proc) {
HMODULE instance = nullptr;
// Converting a pointer-to-function to a void* is undefined behavior, but
// Windows (and POSIX) APIs require it to work.
void* address = reinterpret_cast<void*>(window_proc);
if (!::GetModuleHandleExA(GET_MODULE_HANDLE_EX_FLAG_FROM_ADDRESS |
GET_MODULE_HANDLE_EX_FLAG_UNCHANGED_REFCOUNT,
static_cast<char*>(address), &instance)) {
NOTREACHED();
}
return instance;
}
} // namespace.
namespace base {
namespace win {
WinProcExceptionFilter SetWinProcExceptionFilter(
WinProcExceptionFilter filter) {
return s_exception_filter.exchange(filter, std::memory_order_relaxed);
}
int CallExceptionFilter(EXCEPTION_POINTERS* info) {
base::win::WinProcExceptionFilter filter =
s_exception_filter.load(std::memory_order_relaxed);
return filter ? filter(info) : EXCEPTION_CONTINUE_SEARCH;
}
BASE_EXPORT void InitializeWindowClass(const wchar_t* class_name,
WNDPROC window_proc,
UINT style,
int class_extra,
int window_extra,
HCURSOR cursor,
HBRUSH background,
const wchar_t* menu_name,
HICON large_icon,
HICON small_icon,
WNDCLASSEX* class_out) {
class_out->cbSize = sizeof(WNDCLASSEX);
class_out->style = style;
class_out->lpfnWndProc = window_proc;
class_out->cbClsExtra = class_extra;
class_out->cbWndExtra = window_extra;
// RegisterClassEx uses a handle of the module containing the window procedure
// to distinguish identically named classes registered in different modules.
class_out->hInstance = GetModuleFromWndProc(window_proc);
class_out->hIcon = large_icon;
class_out->hCursor = cursor;
class_out->hbrBackground = background;
class_out->lpszMenuName = menu_name;
class_out->lpszClassName = class_name;
class_out->hIconSm = small_icon;
// Check if |window_proc| is valid.
DCHECK(class_out->hInstance != nullptr);
}
} // namespace win
} // namespace base
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