1 // Copyright (c) 2012 The Chromium Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style license that can be 3 // found in the LICENSE file. 4 5 // Provides a way to handle exceptions that happen while a WindowProc is 6 // running. The behavior of exceptions generated inside a WindowProc is OS 7 // dependent, but it is possible that the OS just ignores the exception and 8 // continues execution, which leads to unpredictable behavior for Chrome. 9 10 #ifndef BASE_WIN_WRAPPED_WINDOW_PROC_H_ 11 #define BASE_WIN_WRAPPED_WINDOW_PROC_H_ 12 13 #include <windows.h> 14 15 #include "base/base_export.h" 16 #include "base/strings/string16.h" 17 18 namespace base { 19 namespace win { 20 21 // An exception filter for a WindowProc. The return value determines how the 22 // exception should be handled, following standard SEH rules. However, the 23 // expected behavior for this function is to not return, instead of returning 24 // EXCEPTION_EXECUTE_HANDLER or similar, given that in general we are not 25 // prepared to handle exceptions. 26 typedef int (__cdecl *WinProcExceptionFilter)(EXCEPTION_POINTERS* info); 27 28 // Sets the filter to deal with exceptions inside a WindowProc. Returns the old 29 // exception filter, if any. 30 // This function should be called before any window is created. 31 BASE_EXPORT WinProcExceptionFilter SetWinProcExceptionFilter( 32 WinProcExceptionFilter filter); 33 34 // Calls the registered exception filter. 35 BASE_EXPORT int CallExceptionFilter(EXCEPTION_POINTERS* info); 36 37 // Initializes the WNDCLASSEX structure |*class_out| to be passed to 38 // RegisterClassEx() making sure that it is associated with the module 39 // containing the window procedure. 40 BASE_EXPORT void InitializeWindowClass( 41 const char16* class_name, 42 WNDPROC window_proc, 43 UINT style, 44 int class_extra, 45 int window_extra, 46 HCURSOR cursor, 47 HBRUSH background, 48 const char16* menu_name, 49 HICON large_icon, 50 HICON small_icon, 51 WNDCLASSEX* class_out); 52 53 // Wrapper that supplies a standard exception frame for the provided WindowProc. 54 // The normal usage is something like this: 55 // 56 // LRESULT CALLBACK MyWinProc(HWND hwnd, UINT message, 57 // WPARAM wparam, LPARAM lparam) { 58 // // Do Something. 59 // } 60 // 61 // ... 62 // 63 // WNDCLASSEX wc = {0}; 64 // wc.lpfnWndProc = WrappedWindowProc<MyWinProc>; 65 // wc.lpszClassName = class_name; 66 // ... 67 // RegisterClassEx(&wc); 68 // 69 // CreateWindowW(class_name, window_name, ... 70 // 71 template <WNDPROC proc> 72 LRESULT CALLBACK WrappedWindowProc(HWND hwnd, UINT message, 73 WPARAM wparam, LPARAM lparam) { 74 LRESULT rv = 0; 75 __try { 76 rv = proc(hwnd, message, wparam, lparam); 77 } __except(CallExceptionFilter(GetExceptionInformation())) { 78 } 79 return rv; 80 } 81 82 } // namespace win 83 } // namespace base 84 85 #endif // BASE_WIN_WRAPPED_WINDOW_PROC_H_ 86
