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

base/win/wrapped_window_proc_unittest.cc

+// 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.
+
+#include "base/win/wrapped_window_proc.h"
+#include "base/message_loop.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace {
+
+DWORD kExceptionCode = 12345;
+WPARAM kCrashMsg = 98765;
+
+// A trivial WindowProc that generates an exception.
+LRESULT CALLBACK TestWindowProc(HWND hwnd, UINT message,
+                                WPARAM wparam, LPARAM lparam) {
+  if (message == kCrashMsg)
+    RaiseException(kExceptionCode, 0, 0, NULL);
+  return DefWindowProc(hwnd, message, wparam, lparam);
+}
+
+// This class implements an exception filter that can be queried about a past
+// exception.
+class TestWrappedExceptionFiter {
+ public:
+  TestWrappedExceptionFiter() : called_(false) {
+    EXPECT_FALSE(s_filter_);
+    s_filter_ = this;
+  }
+
+  ~TestWrappedExceptionFiter() {
+    EXPECT_EQ(s_filter_, this);
+    s_filter_ = NULL;
+  }
+
+  bool called() {
+    return called_;
+  }
+
+  // The actual exception filter just records the exception.
+  static int Filter(EXCEPTION_POINTERS* info) {
+    EXPECT_FALSE(s_filter_->called_);
+    if (info->ExceptionRecord->ExceptionCode == kExceptionCode)
+      s_filter_->called_ = true;
+    return EXCEPTION_EXECUTE_HANDLER;
+  }
+
+ private:
+  bool called_;
+  static TestWrappedExceptionFiter* s_filter_;
+};
+TestWrappedExceptionFiter* TestWrappedExceptionFiter::s_filter_ = NULL;
+
+}  // namespace.
+
+TEST(WrappedWindowProc, CatchesExceptions) {
+  HINSTANCE hinst = GetModuleHandle(NULL);
+  std::wstring class_name(L"TestClass");
+
+  WNDCLASS wc = {0};
+  wc.lpfnWndProc = base::win::WrappedWindowProc<TestWindowProc>;
+  wc.hInstance = hinst;
+  wc.lpszClassName = class_name.c_str();
+  RegisterClass(&wc);
+
+  HWND window = CreateWindow(class_name.c_str(), 0, 0, 0, 0, 0, 0, HWND_MESSAGE,
+                             0, hinst, 0);
+  ASSERT_TRUE(window);
+
+  // Before generating the exception we make sure that the filter will see it.
+  TestWrappedExceptionFiter wrapper;
+  base::win::WinProcExceptionFilter old_filter =
+      base::win::SetWinProcExceptionFilter(TestWrappedExceptionFiter::Filter);
+
+  SendMessage(window, kCrashMsg, 0, 0);
+  EXPECT_TRUE(wrapper.called());
+
+  base::win::SetWinProcExceptionFilter(old_filter);
+}