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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_ | |
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