feat(interaction): add message boxes and text clipboard

CMakeLists.txt

@@ -10,6 +10,7 @@ target_sources(izo
         src/dialogs.cpp
         src/directory_watcher.cpp
         src/time.cpp
+        $<$<PLATFORM_ID:Windows>:src/interaction_windows.cpp>
         $<$<PLATFORM_ID:Windows>:src/dialogs_windows.cpp>
         $<$<PLATFORM_ID:Linux>:src/dialogs_linux.cpp>
 )
@@ -27,7 +28,7 @@ set_target_properties(izo PROPERTIES
 
 if(WIN32)
     target_compile_definitions(izo PRIVATE UNICODE _UNICODE WIN32_LEAN_AND_MEAN NOMINMAX)
-    target_link_libraries(izo PRIVATE ole32 shell32 uuid)
+    target_link_libraries(izo PRIVATE ole32 shell32 uuid user32)
 elseif(UNIX AND NOT APPLE)
     # No link-time desktop dependency. The Linux backend discovers zenity or
     # kdialog at runtime so applications do not inherit GTK or Qt dependencies.

src/interaction_windows.cpp

@@ -0,0 +1,120 @@
+#include <izo/clipboard.hpp>
+#include <izo/message_box.hpp>
+
+#include <windows.h>
+
+#include <string>
+
+namespace izo {
+namespace {
+
+std::wstring widen(std::string_view value) {
+    if (value.empty()) return {};
+    const int count = MultiByteToWideChar(CP_UTF8, MB_ERR_INVALID_CHARS, value.data(),
+                                          static_cast<int>(value.size()), nullptr, 0);
+    if (count <= 0) return {};
+    std::wstring result(static_cast<std::size_t>(count), L'\0');
+    MultiByteToWideChar(CP_UTF8, MB_ERR_INVALID_CHARS, value.data(),
+                        static_cast<int>(value.size()), result.data(), count);
+    return result;
+}
+
+std::string narrow(const wchar_t* value) {
+    if (!value || !*value) return {};
+    const int length = static_cast<int>(wcslen(value));
+    const int count = WideCharToMultiByte(CP_UTF8, 0, value, length, nullptr, 0, nullptr, nullptr);
+    std::string result(static_cast<std::size_t>(count), '\0');
+    WideCharToMultiByte(CP_UTF8, 0, value, length, result.data(), count, nullptr, nullptr);
+    return result;
+}
+
+std::string windows_error(const char* operation) {
+    return std::string(operation) + " failed with error " + std::to_string(GetLastError());
+}
+
+} // namespace
+
+message_response show_message_box(const message_box_options& options, std::string* error_message) {
+    UINT flags = MB_TASKMODAL;
+    switch (options.icon) {
+    case message_icon::info: flags |= MB_ICONINFORMATION; break;
+    case message_icon::warning: flags |= MB_ICONWARNING; break;
+    case message_icon::error: flags |= MB_ICONERROR; break;
+    case message_icon::question: flags |= MB_ICONQUESTION; break;
+    }
+    switch (options.buttons) {
+    case message_buttons::ok: flags |= MB_OK; break;
+    case message_buttons::ok_cancel: flags |= MB_OKCANCEL; break;
+    case message_buttons::yes_no: flags |= MB_YESNO; break;
+    case message_buttons::yes_no_cancel: flags |= MB_YESNOCANCEL; break;
+    }
+    const auto title = widen(options.title);
+    const auto message = widen(options.message);
+    switch (MessageBoxW(nullptr, message.c_str(), title.c_str(), flags)) {
+    case IDOK: return message_response::ok;
+    case IDCANCEL: return message_response::cancel;
+    case IDYES: return message_response::yes;
+    case IDNO: return message_response::no;
+    default:
+        if (error_message) *error_message = windows_error("MessageBoxW");
+        return message_response::error;
+    }
+}
+
+bool set_clipboard_text(std::string_view text, std::string* error_message) {
+    const auto value = widen(text);
+    if (!OpenClipboard(nullptr)) {
+        if (error_message) *error_message = windows_error("OpenClipboard");
+        return false;
+    }
+    EmptyClipboard();
+    const SIZE_T bytes = (value.size() + 1) * sizeof(wchar_t);
+    HGLOBAL memory = GlobalAlloc(GMEM_MOVEABLE, bytes);
+    if (!memory) {
+        if (error_message) *error_message = windows_error("GlobalAlloc");
+        CloseClipboard();
+        return false;
+    }
+    void* destination = GlobalLock(memory);
+    if (!destination) {
+        if (error_message) *error_message = windows_error("GlobalLock");
+        GlobalFree(memory);
+        CloseClipboard();
+        return false;
+    }
+    memcpy(destination, value.c_str(), bytes);
+    GlobalUnlock(memory);
+    if (!SetClipboardData(CF_UNICODETEXT, memory)) {
+        if (error_message) *error_message = windows_error("SetClipboardData");
+        GlobalFree(memory);
+        CloseClipboard();
+        return false;
+    }
+    CloseClipboard();
+    return true;
+}
+
+std::optional<std::string> get_clipboard_text(std::string* error_message) {
+    if (!OpenClipboard(nullptr)) {
+        if (error_message) *error_message = windows_error("OpenClipboard");
+        return std::nullopt;
+    }
+    HANDLE memory = GetClipboardData(CF_UNICODETEXT);
+    if (!memory) {
+        if (error_message) *error_message = "Clipboard does not contain text";
+        CloseClipboard();
+        return std::nullopt;
+    }
+    const auto* value = static_cast<const wchar_t*>(GlobalLock(memory));
+    if (!value) {
+        if (error_message) *error_message = windows_error("GlobalLock");
+        CloseClipboard();
+        return std::nullopt;
+    }
+    auto result = narrow(value);
+    GlobalUnlock(memory);
+    CloseClipboard();
+    return result;
+}
+
+} // namespace izo