add for_each_window and for_each_thread_window helpers (#403)

* fix RegistryTests (warning as errors breaking on signed/unsigned comparison)

* add for_each_window and for_each_thread_window helpers

* .

* simplify wrappers, add child window, can work w/mutable lambdas

* format

* only expose throwing versions when  WIL_ENABLE_EXCEPTIONS is set

* 'format'

* .

* .

* unused result_t

* Update include/wil/windowing.h

Co-authored-by: Duncan Horn <[email protected]>

* Update include/wil/windowing.h

Co-authored-by: Duncan Horn <[email protected]>

* pr fb

---------

Co-authored-by: Duncan Horn <[email protected]>

include/wil/windowing.h

@@ -0,0 +1,164 @@
+//*********************************************************
+//
+// Copyright (c) Microsoft. All rights reserved.
+// This code is licensed under the MIT License.
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF
+// ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED
+// TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
+// PARTICULAR PURPOSE AND NONINFRINGEMENT.
+//
+//*********************************************************
+#ifndef __WIL_WINDOWING_INCLUDED
+#define __WIL_WINDOWING_INCLUDED
+
+#include <WinUser.h>
+#include <exception>
+
+#if WINAPI_FAMILY_PARTITION(WINAPI_PARTITION_DESKTOP)
+namespace wil
+{
+namespace details
+{
+ template <typename T>
+ struct always_false : wistd::false_type
+ {
+ };
+
+ template <typename TEnumApi, typename TCallback>
+ void DoEnumWindowsNoThrow(TEnumApi&& enumApi, TCallback&& callback) noexcept
+ {
+ auto enumproc = [](HWND hwnd, LPARAM lParam) -> BOOL {
+ auto pCallback = reinterpret_cast<TCallback*>(lParam);
+#ifdef __cpp_if_constexpr
+ using result_t = decltype((*pCallback)(hwnd));
+ if constexpr (wistd::is_void_v<result_t>)
+ {
+ (*pCallback)(hwnd);
+ return TRUE;
+ }
+ else if constexpr (wistd::is_same_v<result_t, HRESULT>)
+ {
+ // NB: this works for both HRESULT and NTSTATUS as both S_OK and ERROR_SUCCESS are 0
+ return (S_OK == (*pCallback)(hwnd)) ? TRUE : FALSE;
+ }
+ else if constexpr (std::is_same_v<result_t, bool>)
+ {
+ return (*pCallback)(hwnd) ? TRUE : FALSE;
+ }
+ else
+ {
+ static_assert(details::always_false<TCallback>::value, "Callback must return void, bool, or HRESULT");
+ }
+#else
+ return (*pCallback)(hwnd);
+#endif
+ };
+ enumApi(enumproc, reinterpret_cast<LPARAM>(&callback));
+ }
+
+#ifdef WIL_ENABLE_EXCEPTIONS
+ template <typename TEnumApi, typename TCallback>
+ void DoEnumWindows(TEnumApi&& enumApi, TCallback&& callback)
+ {
+ struct
+ {
+ std::exception_ptr exception;
+ TCallback* pCallback;
+ } callbackData = {nullptr, &callback};
+ auto enumproc = [](HWND hwnd, LPARAM lParam) -> BOOL {
+ auto pCallbackData = reinterpret_cast<decltype(&callbackData)>(lParam);
+ try
+ {
+ auto pCallback = pCallbackData->pCallback;
+#ifdef __cpp_if_constexpr
+ using result_t = decltype((*pCallback)(hwnd));
+ if constexpr (std::is_void_v<result_t>)
+ {
+ (*pCallback)(hwnd);
+ return TRUE;
+ }
+ else if constexpr (std::is_same_v<result_t, HRESULT>)
+ {
+ // NB: this works for both HRESULT and NTSTATUS as both S_OK and ERROR_SUCCESS are 0
+ return (S_OK == (*pCallback)(hwnd)) ? TRUE : FALSE;
+ }
+ else if constexpr (std::is_same_v<result_t, bool>)
+ {
+ return (*pCallback)(hwnd) ? TRUE : FALSE;
+ }
+ else
+ {
+ static_assert(details::always_false<TCallback>::value, "Callback must return void, bool, or HRESULT");
+ }
+#else
+ return (*pCallback)(hwnd);
+#endif
+ }
+ catch (...)
+ {
+ pCallbackData->exception = std::current_exception();
+ return FALSE;
+ }
+ };
+ enumApi(enumproc, reinterpret_cast<LPARAM>(&callbackData));
+ if (callbackData.exception)
+ {
+ std::rethrow_exception(callbackData.exception);
+ }
+ }
+#endif
+} // namespace details
+
+template <typename TCallback>
+void for_each_window_nothrow(TCallback&& callback) noexcept
+{
+ details::DoEnumWindowsNoThrow(&EnumWindows, wistd::forward<TCallback>(callback));
+}
+
+template <typename TCallback>
+void for_each_thread_window_nothrow(_In_ DWORD threadId, TCallback&& callback) noexcept
+{
+ auto boundEnumThreadWindows = [threadId](WNDENUMPROC enumproc, LPARAM lParam) noexcept -> BOOL {
+ return EnumThreadWindows(threadId, enumproc, lParam);
+ };
+ details::DoEnumWindowsNoThrow(boundEnumThreadWindows, wistd::forward<TCallback>(callback));
+}
+
+template <typename TCallback>
+void for_each_child_window_nothrow(_In_ HWND hwndParent, TCallback&& callback) noexcept
+{
+ auto boundEnumChildWindows = [hwndParent](WNDENUMPROC enumproc, LPARAM lParam) noexcept -> BOOL {
+ return EnumChildWindows(hwndParent, enumproc, lParam);
+ };
+ details::DoEnumWindowsNoThrow(boundEnumChildWindows, wistd::forward<TCallback>(callback));
+}
+
+#ifdef WIL_ENABLE_EXCEPTIONS
+template <typename TCallback>
+void for_each_window(TCallback&& callback)
+{
+ details::DoEnumWindows(&EnumWindows, wistd::forward<TCallback>(callback));
+}
+
+template <typename TCallback>
+void for_each_thread_window(_In_ DWORD threadId, TCallback&& callback)
+{
+ auto boundEnumThreadWindows = [threadId](WNDENUMPROC enumproc, LPARAM lParam) noexcept -> BOOL {
+ return EnumThreadWindows(threadId, enumproc, lParam);
+ };
+ details::DoEnumWindows(boundEnumThreadWindows, wistd::forward<TCallback>(callback));
+}
+
+template <typename TCallback>
+void for_each_child_window(_In_ HWND hwndParent, TCallback&& callback)
+{
+ auto boundEnumChildWindows = [hwndParent](WNDENUMPROC enumproc, LPARAM lParam) noexcept -> BOOL {
+ return EnumChildWindows(hwndParent, enumproc, lParam);
+ };
+ details::DoEnumWindows(boundEnumChildWindows, wistd::forward<TCallback>(callback));
+}
+#endif
+
+} // namespace wil
+#endif // WINAPI_FAMILY_PARTITION(WINAPI_PARTITION_DESKTOP)
+#endif // __WIL_WINDOWING_INCLUDED

tests/CMakeLists.txt

@@ -63,6 +63,7 @@ set(COMMON_SOURCES
  ${CMAKE_CURRENT_SOURCE_DIR}/SafeCastTests.cpp
  ${CMAKE_CURRENT_SOURCE_DIR}/TraceLoggingTests.cpp
  ${CMAKE_CURRENT_SOURCE_DIR}/TraceLoggingTests_PartB.cpp
+ ${CMAKE_CURRENT_SOURCE_DIR}/WindowingTests.cpp
  ${CMAKE_CURRENT_SOURCE_DIR}/WistdTests.cpp
  ${CMAKE_CURRENT_SOURCE_DIR}/wiTest.cpp
  ${CMAKE_CURRENT_SOURCE_DIR}/../natvis/wil.natvis