Add an exception wrapper to the WindowProc functions so...

base/win/wrapped_window_proc.h

+// Copyright (c) 2011 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.
+
+// Provides a way to handle exceptions that happen while a WindowProc is
+// running. The behavior of exceptions generated inside a WindowProc is OS
+// dependent, but it is possible that the OS just ignores the exception and
+// continues execution, which leads to unpredictable behavior for Chrome.
+
+#ifndef BASE_WIN_WRAPPED_WINDOW_PROC_H_
+#define BASE_WIN_WRAPPED_WINDOW_PROC_H_
+#pragma once
+
+#include <windows.h>
+
+namespace base {
+namespace win {
+
+// An exception filter for a WindowProc. The return value determines how the
+// exception should be handled, following standard SEH rules. However, the
+// expected behavior for this function is to not return, instead of returning
+// EXCEPTION_EXECUTE_HANDLER or similar, given that in general we are not
+// prepared to handle exceptions.
+typedef int (__cdecl *WinProcExceptionFilter)(EXCEPTION_POINTERS* info);
+
+// Sets the filter to deal with exceptions inside a WindowProc. Returns the old
+// exception filter, if any.
+// This function should be called before any window is created.
+WinProcExceptionFilter SetWinProcExceptionFilter(WinProcExceptionFilter filter);
+
+// Calls the registered exception filter.
+int CallExceptionFilter(EXCEPTION_POINTERS* info);
+
+// Wrapper that supplies a standard exception frame for the provided WindowProc.
+// The normal usage is something like this:
+//
+// LRESULT CALLBACK MyWinProc(HWND hwnd, UINT message,
+//                            WPARAM wparam, LPARAM lparam) {
+//   // Do Something.
+// }
+//
+// ...
+//
+//   WNDCLASSEX wc = {0};
+//   wc.lpfnWndProc = WrappedWindowProc<MyWinProc>;
+//   wc.lpszClassName = class_name;
+//   ...
+//   RegisterClassEx(&wc);
+//
+//   CreateWindowW(class_name, window_name, ...
+//
+template <WNDPROC proc>

[cpu_(ooo_6.6-7.5), 2011/03/16 00:12:37]

it feels that we could do
template <WNDPROC proc, EXFILTER filter>

Or do we expect that we actually are going to switch filters at runtime? or for
it to be NULL ?

[rvargas (doing something else), 2011/03/16 00:25:07]

The idea is that the filter is not provided by the implementor of the
WindowProc... if they have to be aware of SEH and breakpad, we might as well
remove the template.

+LRESULT CALLBACK WrappedWindowProc(HWND hwnd, UINT message,
+                                   WPARAM wparam, LPARAM lparam) {
+  LRESULT rv = 0;
+  __try {
+    rv = proc(hwnd, message, wparam, lparam);
+  } __except(CallExceptionFilter(GetExceptionInformation())) {
+  }
+  return rv;
+}
+
+}  // namespace win
+}  // namespace base
+
+#endif  // BASE_WIN_WRAPPED_WINDOW_PROC_H_