Linux/Wayland: Support parent windows

.github/workflows/cmake.yml

@@ -46,36 +46,47 @@ jobs:
         os: [ {label: ubuntu-latest, name: latest}, {label: ubuntu-20.04, name: 20.04} ]
         portal: [ {flag: OFF, dep: libgtk-3-dev, name: GTK}, {flag: ON, dep: libdbus-1-dev, name: Portal} ] # The NFD_PORTAL setting defaults to OFF (i.e. uses GTK)
         autoappend: [ {flag: OFF, name: NoAppendExtn} ] # By default the NFD_PORTAL mode does not append extensions, because it breaks some features of the portal
+        wayland: [ {flag: OFF, name: NoWayland} ]
         compiler: [ {c: gcc, cpp: g++, name: GCC}, {c: clang, cpp: clang++, name: Clang} ] # The default compiler is gcc/g++
         cppstd: [20, 11]
         shared_lib: [ {flag: OFF, name: Static} ]
         include:
         - os: {label: ubuntu-latest, name: latest}
           portal: {flag: ON, dep: libdbus-1-dev, name: Portal}
           autoappend: {flag: ON, name: AutoAppendExtn}
+          wayland: {flag: OFF, name: NoWayland}
           compiler: {c: gcc, cpp: g++, name: GCC}
           cppstd: 11
           shared_lib: {flag: OFF, name: Static}
         - os: {label: ubuntu-latest, name: latest}
           portal: {flag: ON, dep: libdbus-1-dev, name: Portal}
           autoappend: {flag: ON, name: AutoAppendExtn}
+          wayland: {flag: OFF, name: NoWayland}
           compiler: {c: clang, cpp: clang++, name: Clang}
           cppstd: 11
           shared_lib: {flag: OFF, name: Static}
         - os: {label: ubuntu-latest, name: latest}
           portal: {flag: ON, dep: libdbus-1-dev, name: Portal}
           autoappend: {flag: OFF, name: NoAppendExtn}
+          wayland: {flag: OFF, name: NoWayland}
           compiler: {c: gcc, cpp: g++, name: GCC}
           cppstd: 11
           shared_lib: {flag: ON, name: Shared}
+        - os: {label: ubuntu-latest, name: latest}
+          portal: {flag: ON, dep: libdbus-1-dev, name: Portal}
+          autoappend: {flag: OFF, name: NoAppendExtn}
+          wayland: {flag: ON, name: Wayland}
+          compiler: {c: gcc, cpp: g++, name: GCC}
+          cppstd: 11
+          shared_lib: {flag: ON, name: Static}
 
     steps:
     - name: Checkout
       uses: actions/checkout@v4
     - name: Install Dependencies
       run: sudo apt-get update && sudo apt-get install ${{ matrix.portal.dep }}
     - name: Configure
-      run: mkdir build && mkdir install && cd build && cmake -DCMAKE_INSTALL_PREFIX="../install" -DCMAKE_BUILD_TYPE=Release -DCMAKE_C_COMPILER=${{ matrix.compiler.c }} -DCMAKE_CXX_COMPILER=${{ matrix.compiler.cpp }} -DCMAKE_CXX_STANDARD=${{ matrix.cppstd }} -DCMAKE_C_FLAGS="-Wall -Wextra -Wshadow -Werror -pedantic" -DCMAKE_CXX_FLAGS="-Wall -Wextra -Wshadow -Werror -pedantic" -DNFD_PORTAL=${{ matrix.portal.flag }} -DNFD_APPEND_EXTENSION=${{ matrix.autoappend.flag }} -DBUILD_SHARED_LIBS=${{ matrix.shared_lib.flag }} -DNFD_BUILD_TESTS=ON ..
+      run: mkdir build && mkdir install && cd build && cmake -DCMAKE_INSTALL_PREFIX="../install" -DCMAKE_BUILD_TYPE=Release -DCMAKE_C_COMPILER=${{ matrix.compiler.c }} -DCMAKE_CXX_COMPILER=${{ matrix.compiler.cpp }} -DCMAKE_CXX_STANDARD=${{ matrix.cppstd }} -DCMAKE_C_FLAGS="-Wall -Wextra -Wshadow -Werror -pedantic" -DCMAKE_CXX_FLAGS="-Wall -Wextra -Wshadow -Werror -pedantic" -DNFD_WAYLAND=OFF -DNFD_PORTAL=${{ matrix.portal.flag }} -DNFD_APPEND_EXTENSION=${{ matrix.autoappend.flag }} -DBUILD_SHARED_LIBS=${{ matrix.shared_lib.flag }} -DNFD_BUILD_TESTS=ON ..
     - name: Build
       run: cmake --build build --target install
     - name: Upload test binaries

.gitmodules

@@ -0,0 +1,3 @@
+[submodule "3ps/wayland-protocols"]
+	path = 3ps/wayland-protocols
+	url = https://gitlab.freedesktop.org/wayland/wayland-protocols.git

src/CMakeLists.txt

@@ -18,13 +18,33 @@ if(nfd_PLATFORM STREQUAL PLATFORM_LINUX)
   option(NFD_PORTAL "Use xdg-desktop-portal instead of GTK" OFF)
   if(NOT NFD_PORTAL)
     pkg_check_modules(GTK3 REQUIRED gtk+-3.0)
-    message("Using GTK version: ${GTK3_VERSION}")
+    message(STATUS "Using GTK version: ${GTK3_VERSION}")
     list(APPEND SOURCE_FILES nfd_gtk.cpp)
   else()
     pkg_check_modules(DBUS REQUIRED dbus-1)
-    message("Using DBUS version: ${DBUS_VERSION}")
+    message(STATUS "Using D-Bus version: ${DBUS_VERSION}")
     list(APPEND SOURCE_FILES nfd_portal.cpp)
   endif()
+
+  # for Linux, we support X11, Wayland, or both
+  option(NFD_X11 "Support X11 on Linux" ON)
+  option(NFD_WAYLAND "Support Wayland on Linux" ON)
+  if(NFD_WAYLAND)
+    pkg_check_modules(WAYLAND REQUIRED wayland-client)
+    message(STATUS "Using Wayland version: ${WAYLAND_VERSION}")
+    set(NFD_WAYLAND_PROTOCOL_XDG_FOREIGN ${CMAKE_CURRENT_SOURCE_DIR}/../3ps/wayland-protocols/unstable/xdg-foreign/xdg-foreign-unstable-v1.xml)
+    add_custom_command(
+      OUTPUT ${CMAKE_CURRENT_BINARY_DIR}/xdg-foreign-unstable-v1.h
+      COMMAND wayland-scanner client-header < ${NFD_WAYLAND_PROTOCOL_XDG_FOREIGN} > ${CMAKE_CURRENT_BINARY_DIR}/xdg-foreign-unstable-v1.h
+      MAIN_DEPENDENCY ${NFD_WAYLAND_PROTOCOL_XDG_FOREIGN}
+    )
+    add_custom_command(
+      OUTPUT ${CMAKE_CURRENT_BINARY_DIR}/xdg-foreign-unstable-v1.c
+      COMMAND wayland-scanner private-code < ${NFD_WAYLAND_PROTOCOL_XDG_FOREIGN} > ${CMAKE_CURRENT_BINARY_DIR}/xdg-foreign-unstable-v1.c
+      MAIN_DEPENDENCY ${NFD_WAYLAND_PROTOCOL_XDG_FOREIGN}
+    )
+    list(APPEND SOURCE_FILES ${CMAKE_CURRENT_BINARY_DIR}/xdg-foreign-unstable-v1.h ${CMAKE_CURRENT_BINARY_DIR}/xdg-foreign-unstable-v1.c)
+  endif()
 endif()
 
 if(nfd_PLATFORM STREQUAL PLATFORM_MACOS)
@@ -94,6 +114,16 @@ if(nfd_PLATFORM STREQUAL PLATFORM_LINUX)
   if(NFD_APPEND_EXTENSION)
     target_compile_definitions(${TARGET_NAME} PRIVATE NFD_APPEND_EXTENSION)
   endif()
+
+  if(NFD_X11)
+    target_compile_definitions(${TARGET_NAME} PRIVATE NFD_X11)
+  endif()
+  if(NFD_WAYLAND)
+    target_include_directories(${TARGET_NAME} PRIVATE ${WAYLAND_INCLUDE_DIRS})
+    target_link_libraries(${TARGET_NAME} PRIVATE ${WAYLAND_LINK_LIBRARIES})
+    target_compile_definitions(${TARGET_NAME} PRIVATE NFD_WAYLAND)
+    target_include_directories(${TARGET_NAME} PRIVATE ${CMAKE_CURRENT_BINARY_DIR})
+  endif()
 endif()
 
 if(nfd_PLATFORM STREQUAL PLATFORM_MACOS)
@@ -118,7 +148,7 @@ if(nfd_COMPILER STREQUAL COMPILER_CLANGCL)
 endif()
 
 if(nfd_COMPILER STREQUAL COMPILER_GNU)
-  target_compile_options(${TARGET_NAME} PRIVATE -nostdlib -fno-exceptions -fno-rtti)
+  target_compile_options(${TARGET_NAME} PRIVATE -nostdlib -fno-exceptions $<$<COMPILE_LANGUAGE:CXX>:-fno-rtti>)
 endif()
 
 set_target_properties(${TARGET_NAME} PROPERTIES

src/include/nfd.h

@@ -105,7 +105,8 @@ enum {
     NFD_WINDOW_HANDLE_TYPE_COCOA = 2,
     // X11: handle is Window
     NFD_WINDOW_HANDLE_TYPE_X11 = 3,
-    // Wayland support will be implemented separately in the future
+    // Wayland: handle is wl_surface*
+    NFD_WINDOW_HANDLE_TYPE_WAYLAND = 4,
 };
 // The native window handle.  If using a platform abstraction framework (e.g. SDL2), this should be
 // obtained using the corresponding NFD glue header (e.g. nfd_sdl2.h).

src/nfd_portal.cpp

@@ -26,6 +26,15 @@
 #define getrandom(buf, sz, flags) syscall(SYS_getrandom, buf, sz, flags)
 #endif
 
+#ifdef NFD_WAYLAND
+#include <wayland-client.h>
+#include "xdg-foreign-unstable-v1.h"
+struct wl_display* wayland_display;
+struct wl_registry* wayland_registry;
+uint32_t wayland_xdg_exporter_v1_name;
+struct zxdg_exporter_v1* wayland_xdg_exporter_v1;
+#endif
+
 #include "nfd.h"
 
 /*
@@ -68,6 +77,17 @@ struct FreeCheck_Guard {
     }
 };
 
+void EmptyFn(void*) {}
+
+struct DestroyFunc {
+    DestroyFunc() : fn(&EmptyFn), context(nullptr) {}
+    ~DestroyFunc() {
+        (*fn)(context);
+    }
+    void(*fn)(void*);
+    void* context;
+};
+
 struct DBusMessage_Guard {
     DBusMessage* data;
     DBusMessage_Guard(DBusMessage* freeable) noexcept : data(freeable) {}
@@ -172,9 +192,43 @@ constexpr const char* DBUS_PATH = "/org/freedesktop/portal/desktop";
 constexpr const char* DBUS_FILECHOOSER_IFACE = "org.freedesktop.portal.FileChooser";
 constexpr const char* DBUS_REQUEST_IFACE = "org.freedesktop.portal.Request";
 
-void AppendOpenFileQueryParentWindow(DBusMessageIter& iter, const nfdwindowhandle_t& parentWindow) {
+#ifdef NFD_WAYLAND
+constexpr const char* XDG_EXPORTER_V1 = "zxdg_exporter_v1";
+constexpr const char* WAYLAND_PREFIX = "wayland:";
+
+void DestroyXdgExported(void* context) {
+    zxdg_exported_v1_destroy(static_cast<struct zxdg_exported_v1*>(context));
+}
+
+void zxdg_exported_v1_handle(void* context,
+		       struct zxdg_exported_v1* zxdg_exported_v1,
+		       const char* handle) {
+    if (!context) return;
+    DBusMessageIter& iter = *static_cast<DBusMessageIter*>(context);
+    const size_t handle_len = strlen(handle);
+    const size_t prefix_len = strlen(WAYLAND_PREFIX);
+    char* const buf = NFDi_Malloc<char>(prefix_len + handle_len + 1);
+    char* buf_end = copy(WAYLAND_PREFIX, WAYLAND_PREFIX + prefix_len, buf);
+    buf_end = copy(handle, handle+handle_len, buf_end);
+    *buf_end = '\0';
+    dbus_message_iter_append_basic(&iter, DBUS_TYPE_STRING, &buf);
+    NFDi_Free(buf);
+}
+
+constexpr struct zxdg_exported_v1_listener wayland_xdg_exported_v1_listener {
+    &zxdg_exported_v1_handle
+};
+#endif
+
+void AppendOpenFileQueryParentWindow(DBusMessageIter& iter, const nfdwindowhandle_t& parentWindow, void(*&destroyFn)(void*), void*& destroyFnContext) {
+    (void) iter;
+    (void) parentWindow;
+    (void) destroyFn;
+    (void) destroyFnContext;
     switch (parentWindow.type) {
+#ifdef NFD_X11
         case NFD_WINDOW_HANDLE_TYPE_X11: {
+            fprintf(stderr, "X11\n");
             constexpr size_t maxX11WindowStrLen =
                 4 + sizeof(uintptr_t) * 2 + 1;  // "x11:" + "<hex>" + "\0"
             char serializedWindowBuf[maxX11WindowStrLen];
@@ -190,6 +244,26 @@ void AppendOpenFileQueryParentWindow(DBusMessageIter& iter, const nfdwindowhandl
             dbus_message_iter_append_basic(&iter, DBUS_TYPE_STRING, &serializedWindow);
             return;
         }
+#endif
+#ifdef NFD_WAYLAND
+        case NFD_WINDOW_HANDLE_TYPE_WAYLAND: {
+            fprintf(stderr, "Wayland\n");
+            if (wayland_xdg_exporter_v1) {
+                struct zxdg_exported_v1* exported = zxdg_exporter_v1_export(wayland_xdg_exporter_v1, static_cast<struct wl_surface*>(parentWindow.handle));
+                if (!exported) {
+                    // if we fail to export the wl_surface, act as if the window has no parent
+                    dbus_message_iter_append_basic(&iter, DBUS_TYPE_STRING, &STR_EMPTY);
+                    return;
+                }
+                zxdg_exported_v1_add_listener(exported, &wayland_xdg_exported_v1_listener, static_cast<void*>(&iter));
+                wl_display_roundtrip(wayland_display);
+                zxdg_exported_v1_set_user_data(exported, nullptr);
+                destroyFn = &DestroyXdgExported;
+                destroyFnContext = static_cast<void*>(exported);
+            }
+            return;
+        }
+#endif
         default: {
             dbus_message_iter_append_basic(&iter, DBUS_TYPE_STRING, &STR_EMPTY);
             return;
@@ -619,11 +693,11 @@ void AppendOpenFileQueryParams(DBusMessage* query,
                                const nfdnfilteritem_t* filterList,
                                nfdfiltersize_t filterCount,
                                const nfdnchar_t* defaultPath,
-                               const nfdwindowhandle_t& parentWindow) {
+                               const nfdwindowhandle_t& parentWindow, void(*&destroyFn)(void*), void*& destroyFnContext) {
     DBusMessageIter iter;
     dbus_message_iter_init_append(query, &iter);
 
-    AppendOpenFileQueryParentWindow(iter, parentWindow);
+    AppendOpenFileQueryParentWindow(iter, parentWindow, destroyFn, destroyFnContext);
     AppendOpenFileQueryTitle<Multiple, Directory>(iter);
 
     DBusMessageIter sub_iter;
@@ -643,11 +717,11 @@ void AppendSaveFileQueryParams(DBusMessage* query,
                                nfdfiltersize_t filterCount,
                                const nfdnchar_t* defaultPath,
                                const nfdnchar_t* defaultName,
-                               const nfdwindowhandle_t& parentWindow) {
+                               const nfdwindowhandle_t& parentWindow, void(*&destroyFn)(void*), void*& destroyFnContext) {
     DBusMessageIter iter;
     dbus_message_iter_init_append(query, &iter);
 
-    AppendOpenFileQueryParentWindow(iter, parentWindow);
+    AppendOpenFileQueryParentWindow(iter, parentWindow, destroyFn, destroyFnContext);
     AppendSaveFileQueryTitle(iter);
 
     DBusMessageIter sub_iter;
@@ -1195,8 +1269,10 @@ nfdresult_t NFD_DBus_OpenFile(DBusMessage*& outMsg,
     DBusMessage* query = dbus_message_new_method_call(
         DBUS_DESTINATION, DBUS_PATH, DBUS_FILECHOOSER_IFACE, "OpenFile");
     DBusMessage_Guard query_guard(query);
+
+    DestroyFunc destroy;
     AppendOpenFileQueryParams<Multiple, Directory>(
-        query, handle_token_ptr, filterList, filterCount, defaultPath, parentWindow);
+        query, handle_token_ptr, filterList, filterCount, defaultPath, parentWindow, destroy.fn, destroy.context);
 
     DBusMessage* reply =
         dbus_connection_send_with_reply_and_block(dbus_conn, query, DBUS_TIMEOUT_INFINITE, &err);
@@ -1278,8 +1354,10 @@ nfdresult_t NFD_DBus_SaveFile(DBusMessage*& outMsg,
     DBusMessage* query = dbus_message_new_method_call(
         DBUS_DESTINATION, DBUS_PATH, DBUS_FILECHOOSER_IFACE, "SaveFile");
     DBusMessage_Guard query_guard(query);
+
+    DestroyFunc destroy;
     AppendSaveFileQueryParams(
-        query, handle_token_ptr, filterList, filterCount, defaultPath, defaultName, parentWindow);
+        query, handle_token_ptr, filterList, filterCount, defaultPath, defaultName, parentWindow, destroy.fn, destroy.context);
 
     DBusMessage* reply =
         dbus_connection_send_with_reply_and_block(dbus_conn, query, DBUS_TIMEOUT_INFINITE, &err);
@@ -1383,6 +1461,27 @@ nfdresult_t NFD_DBus_GetVersion(dbus_uint32_t& outVersion) {
     return NFD_OKAY;
 }
 
+#ifdef NFD_WAYLAND
+void registry_handle_global(void* context, struct wl_registry* registry, uint32_t name, const char* interface, uint32_t version) {
+    if (strcmp(interface, XDG_EXPORTER_V1) == 0) {
+        wayland_xdg_exporter_v1_name = name;
+        wayland_xdg_exporter_v1 = static_cast<struct zxdg_exporter_v1*>(wl_registry_bind(registry, name, &zxdg_exporter_v1_interface, zxdg_exporter_v1_interface.version));
+    }
+}
+
+void registry_handle_global_remove(void* context, struct wl_registry* registry, uint32_t name) {
+    if (wayland_xdg_exporter_v1 && name == wayland_xdg_exporter_v1_name) {
+        zxdg_exporter_v1_destroy(wayland_xdg_exporter_v1);
+        wayland_xdg_exporter_v1 = nullptr;
+    }
+}
+
+constexpr struct wl_registry_listener wayland_registry_listener = {
+    &registry_handle_global,
+    &registry_handle_global_remove
+};
+#endif
+
 }  // namespace
 
 /* public */
@@ -1408,11 +1507,30 @@ nfdresult_t NFD_Init(void) {
     dbus_unique_name = dbus_bus_get_unique_name(dbus_conn);
     if (!dbus_unique_name) {
         NFDi_SetError("Unable to get the unique name of our D-Bus connection.");
+        dbus_connection_unref(dbus_conn);
         return NFD_ERROR;
     }
+#ifdef NFD_WAYLAND
+    // This might fail, but it is fine because the system might not actually have Wayland installed
+    wayland_display = wl_display_connect(nullptr);
+    if (wayland_display) {
+        wayland_registry = wl_display_get_registry(wayland_display);
+        wayland_xdg_exporter_v1 = nullptr;
+        // seems like registry can't be null
+        wl_registry_add_listener(wayland_registry, &wayland_registry_listener, nullptr);
+        wl_display_roundtrip(wayland_display);
+    }
+#endif
     return NFD_OKAY;
 }
 void NFD_Quit(void) {
+#ifdef NFD_WAYLAND
+    if (wayland_display) {
+        if (wayland_xdg_exporter_v1) zxdg_exporter_v1_destroy(wayland_xdg_exporter_v1);
+        wl_registry_destroy(wayland_registry);
+        wl_display_disconnect(wayland_display);
+    }
+#endif
     dbus_connection_unref(dbus_conn);
     // Note: We do not free dbus_error since NFD_Init might set it.
     // To avoid leaking memory, the caller should explicitly call NFD_ClearError after reading the