[client] wayland: move libdecor and xdg into seperate backends

This allows us to build with libdecor enabled as the selection to use it
is decided upon at runtime if the compositor `gnome-shell` is detected.
If the libdecor development headers are installed, by default it will
now be compiled in unless overridden by the user at compile time.

client/displayservers/Wayland/desktops/CMakeLists.txt

@@ -0,0 +1,58 @@
+cmake_minimum_required(VERSION 3.0)
+project(wayland_desktops LANGUAGES C)
+
+set(DESKTOP_H "${CMAKE_BINARY_DIR}/include/dynamic/wayland_desktops.h")
+set(DESKTOP_C "${CMAKE_BINARY_DIR}/src/wayland_desktops.c")
+
+file(WRITE  ${DESKTOP_H} "#include \"interface/desktop.h\"\n\n")
+file(APPEND ${DESKTOP_H} "extern struct WL_DesktopOps * WL_Desktops[];\n\n")
+
+file(WRITE  ${DESKTOP_C} "#include \"interface/desktop.h\"\n\n")
+file(APPEND ${DESKTOP_C} "#include <stddef.h>\n\n")
+
+set(DESKTOPS "_")
+set(DESKTOPS_LINK "_")
+function(add_desktop name)
+  set(DESKTOPS      "${DESKTOPS};${name}" PARENT_SCOPE)
+  set(DESKTOPS_LINK "${DESKTOPS_LINK};wayland_desktop_${name}" PARENT_SCOPE)
+  add_subdirectory(${name})
+endfunction()
+
+# Add/remove desktops here!
+
+# the first entry here is the default
+add_desktop(xdg)
+
+pkg_check_modules(LIBDECOR REQUIRED IMPORTED_TARGET libdecor-0)
+if(LIBDECOR_FOUND)
+  option(ENABLE_LIBDECOR "Build with libdecor support" ON)
+else()
+  option(ENABLE_LIBDECOR "Build with libdecor support" OFF)
+endif()
+add_feature_info(ENABLE_LIBDECOR ENABLE_LIBDECOR "libdecor support.")
+if (ENABLE_LIBDECOR)
+  add_desktop(libdecor)
+endif()
+
+list(REMOVE_AT DESKTOPS      0)
+list(REMOVE_AT DESKTOPS_LINK 0)
+
+list(LENGTH DESKTOPS DESKTOP_COUNT)
+file(APPEND ${DESKTOP_H} "#define WL_DESKTOP_COUNT ${DESKTOP_COUNT}\n")
+
+foreach(desktop ${DESKTOPS})
+  file(APPEND ${DESKTOP_C} "extern struct WL_DesktopOps WLD_${desktop};\n")
+endforeach()
+
+file(APPEND ${DESKTOP_C} "\nconst struct WL_DesktopOps * WL_Desktops[] =\n{\n")
+foreach(desktop ${DESKTOPS})
+  file(APPEND ${DESKTOP_C} "  &WLD_${desktop},\n")
+endforeach()
+file(APPEND ${DESKTOP_C} "  NULL\n};")
+
+add_library(wayland_desktops STATIC ${DESKTOP_C})
+target_link_libraries(wayland_desktops ${DESKTOPS_LINK})
+target_include_directories(wayland_desktops
+  PRIVATE
+    ../
+)

client/displayservers/Wayland/desktops/libdecor/CMakeLists.txt

@@ -0,0 +1,16 @@
+cmake_minimum_required(VERSION 3.0)
+project(wayland_desktop_libdecor LANGUAGES C)
+
+add_library(wayland_desktop_libdecor STATIC
+  libdecor.c
+)
+
+target_link_libraries(wayland_desktop_libdecor
+  lg_common
+  wayland_protocol
+  PkgConfig::LIBDECOR
+)
+
+include_directories(
+  "../../"
+)

client/displayservers/Wayland/desktops/libdecor/libdecor.c

@@ -0,0 +1,269 @@
+/**
+ * Looking Glass
+ * Copyright © 2017-2023 The Looking Glass Authors
+ * https://looking-glass.io
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the Free
+ * Software Foundation; either version 2 of the License, or (at your option)
+ * any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc., 59
+ * Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+
+#include "interface/desktop.h"
+#include "wayland-xdg-shell-client-protocol.h"
+
+#include "wayland.h"
+
+#include <errno.h>
+#include <stdbool.h>
+#include <string.h>
+#include <sys/epoll.h>
+
+#include <libdecor.h>
+#include <wayland-client.h>
+
+#include "app.h"
+#include "common/debug.h"
+
+// Maximum number of fds we can process at once in waylandWait
+#define MAX_EPOLL_EVENTS 10
+
+typedef struct LibDecorState
+{
+  bool configured;
+  struct libdecor       * libdecor;
+  struct libdecor_frame * libdecorFrame;
+
+  int32_t width, height;
+  bool     needsResize;
+  bool     fullscreen;
+  uint32_t resizeSerial;
+}
+LibDecorState;
+
+static LibDecorState state = {0};
+
+struct libdecor_configuration
+{
+  uint32_t serial;
+
+  bool has_window_state;
+  enum libdecor_window_state window_state;
+
+  bool has_size;
+  int  window_width;
+  int  window_height;
+};
+
+static void libdecorHandleError(struct libdecor * context, enum libdecor_error error,
+    const char *message)
+{
+  DEBUG_ERROR("Got libdecor error (%d): %s", error, message);
+}
+
+static void libdecorFrameConfigure(struct libdecor_frame * frame,
+    struct libdecor_configuration * configuration, void * opaque)
+{
+  if (!state.configured)
+  {
+    xdg_surface_ack_configure(libdecor_frame_get_xdg_surface(frame), configuration->serial);
+    state.configured = true;
+    return;
+  }
+
+  int width, height;
+  if (libdecor_configuration_get_content_size(configuration, frame, &width, &height))
+  {
+    state.width  = width;
+    state.height = height;
+
+    struct libdecor_state * s = libdecor_state_new(width, height);
+    libdecor_frame_commit(state.libdecorFrame, s, NULL);
+    libdecor_state_free(s);
+  }
+
+  enum libdecor_window_state windowState;
+  if (libdecor_configuration_get_window_state(configuration, &windowState))
+    state.fullscreen = windowState & LIBDECOR_WINDOW_STATE_FULLSCREEN;
+
+  state.resizeSerial = configuration->serial;
+  waylandNeedsResize();
+}
+
+static void libdecorFrameClose(struct libdecor_frame * frame, void * opaque)
+{
+  app_handleCloseEvent();
+}
+
+static void libdecorFrameCommit(struct libdecor_frame * frame, void * opaque)
+{
+}
+
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wmissing-field-initializers"
+static struct libdecor_interface libdecorListener =
+{
+  libdecorHandleError,
+};
+
+static struct libdecor_frame_interface libdecorFrameListener =
+{
+  libdecorFrameConfigure,
+  libdecorFrameClose,
+  libdecorFrameCommit,
+};
+#pragma GCC diagnostic pop
+
+static void libdecorCallback(uint32_t events, void * opaque)
+{
+  libdecor_dispatch(state.libdecor, 0);
+}
+
+static bool libdecor_shellInit(
+    struct wl_display * display, struct wl_surface * surface,
+    const char * title, bool fullscreen,
+    bool maximize, bool borderless, bool resizable)
+{
+  state.libdecor = libdecor_new(display, &libdecorListener);
+  state.libdecorFrame = libdecor_decorate(state.libdecor, surface,
+      &libdecorFrameListener, NULL);
+
+  libdecor_frame_set_app_id(state.libdecorFrame, "looking-glass-client");
+  libdecor_frame_set_title(state.libdecorFrame, title);
+  libdecor_frame_map(state.libdecorFrame);
+
+  if (resizable)
+    libdecor_frame_set_capabilities(state.libdecorFrame,
+        LIBDECOR_ACTION_RESIZE);
+  else
+    libdecor_frame_unset_capabilities(state.libdecorFrame,
+        LIBDECOR_ACTION_RESIZE);
+
+  while (!state.configured)
+    libdecor_dispatch(state.libdecor, 0);
+
+  if (!waylandPollRegister(libdecor_get_fd(state.libdecor),
+        libdecorCallback, NULL, EPOLLIN))
+  {
+    DEBUG_ERROR("Failed register display to epoll: %s", strerror(errno));
+    return false;
+  }
+  return true;
+}
+
+static void libdecor_shellAckConfigureIfNeeded(void)
+{
+  if (state.resizeSerial)
+  {
+    xdg_surface_ack_configure(
+        libdecor_frame_get_xdg_surface(state.libdecorFrame), state.resizeSerial);
+    state.resizeSerial = 0;
+  }
+}
+
+static void libdecor_setFullscreen(bool fs)
+{
+  if (fs)
+    libdecor_frame_set_fullscreen(state.libdecorFrame, NULL);
+  else
+    libdecor_frame_unset_fullscreen(state.libdecorFrame);
+
+  libdecor_frame_set_visibility(state.libdecorFrame, !fs);
+}
+
+static bool libdecor_getFullscreen(void)
+{
+  return state.fullscreen;
+}
+
+static void libdecor_minimize(void)
+{
+  libdecor_frame_set_minimized(state.libdecorFrame);
+}
+
+static void libdecor_shellResize(int w, int h)
+{
+  if (!libdecor_frame_is_floating(state.libdecorFrame))
+    return;
+
+  state.width  = w;
+  state.height = h;
+
+  struct libdecor_state * s = libdecor_state_new(w, h);
+  libdecor_frame_commit(state.libdecorFrame, s, NULL);
+  libdecor_state_free(s);
+
+  waylandNeedsResize();
+}
+
+static void libdecor_setSize(int w, int h)
+{
+  state.width  = w;
+  state.height = h;
+}
+
+static void libdecor_getSize(int * w, int * h)
+{
+  *w = state.width;
+  *h = state.height;
+}
+
+static bool libdecor_registryGlobalHandler(void * data,
+    struct wl_registry * registry, uint32_t name, const char * interface,
+    uint32_t version)
+{
+  return false;
+}
+
+bool libdecor_pollInit(struct wl_display * display)
+{
+  return true;
+}
+
+void libdecor_pollWait(struct wl_display * display, int epollFd,
+    unsigned int time)
+{
+  libdecor_dispatch(state.libdecor, 0);
+
+  struct epoll_event events[MAX_EPOLL_EVENTS];
+  int count;
+  if ((count = epoll_wait(epollFd, events, MAX_EPOLL_EVENTS, time)) < 0)
+  {
+    if (errno != EINTR)
+      DEBUG_INFO("epoll failed: %s", strerror(errno));
+    return;
+  }
+
+  for (int i = 0; i < count; ++i)
+  {
+    struct WaylandPoll * poll = events[i].data.ptr;
+    if (!poll->removed)
+      poll->callback(events[i].events, poll->opaque);
+  }
+}
+
+WL_DesktopOps WLD_libdecor =
+{
+  .name                      = "libdecor",
+  .compositor                = "gnome-shell",
+  .shellInit                 = libdecor_shellInit,
+  .shellAckConfigureIfNeeded = libdecor_shellAckConfigureIfNeeded,
+  .setFullscreen             = libdecor_setFullscreen,
+  .getFullscreen             = libdecor_getFullscreen,
+  .minimize                  = libdecor_minimize,
+  .shellResize               = libdecor_shellResize,
+  .setSize                   = libdecor_setSize,
+  .getSize                   = libdecor_getSize,
+  .registryGlobalHandler     = libdecor_registryGlobalHandler,
+  .pollInit                  = libdecor_pollInit,
+  .pollWait                  = libdecor_pollWait
+};

client/displayservers/Wayland/desktops/xdg/CMakeLists.txt

@@ -0,0 +1,15 @@
+cmake_minimum_required(VERSION 3.0)
+project(wayland_desktop_xdg LANGUAGES C)
+
+add_library(wayland_desktop_xdg STATIC
+  xdg.c
+)
+
+target_link_libraries(wayland_desktop_xdg
+  lg_common
+  wayland_protocol
+)
+
+include_directories(
+  "../../"
+)

client/displayservers/Wayland/desktops/xdg/xdg.c

@@ -0,0 +1,314 @@
+/**
+ * Looking Glass
+ * Copyright © 2017-2023 The Looking Glass Authors
+ * https://looking-glass.io
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the Free
+ * Software Foundation; either version 2 of the License, or (at your option)
+ * any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc., 59
+ * Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+
+#include "wayland.h"
+#include "wayland-xdg-shell-client-protocol.h"
+#include "wayland-xdg-decoration-unstable-v1-client-protocol.h"
+
+#include <stdbool.h>
+#include <string.h>
+#include <sys/epoll.h>
+#include <errno.h>
+
+#include <wayland-client.h>
+
+#include "app.h"
+#include "common/debug.h"
+
+// Maximum number of fds we can process at once in waylandWait
+#define MAX_EPOLL_EVENTS 10
+
+typedef struct XDGState
+{
+  bool configured;
+
+  struct xdg_wm_base                 * wmBase;
+  struct xdg_surface                 * surface;
+  struct xdg_toplevel                * toplevel;
+  struct zxdg_decoration_manager_v1  * decorationManager;
+  struct zxdg_toplevel_decoration_v1 * toplevelDecoration;
+
+  int32_t width, height;
+  uint32_t resizeSerial;
+  bool fullscreen;
+  bool floating;
+  int displayFd;
+}
+XDGState;
+
+static XDGState state = {0};
+
+// XDG WM base listeners.
+
+static void xdgWmBasePing(void * data, struct xdg_wm_base * xdgWmBase, uint32_t serial)
+{
+  xdg_wm_base_pong(xdgWmBase, serial);
+}
+
+static const struct xdg_wm_base_listener xdgWmBaseListener = {
+  .ping = xdgWmBasePing,
+};
+
+// XDG Surface listeners.
+
+static void xdgSurfaceConfigure(void * data, struct xdg_surface * xdgSurface,
+    uint32_t serial)
+{
+  if (state.configured)
+  {
+    state.resizeSerial = serial;
+    waylandNeedsResize();
+  }
+  else
+  {
+    xdg_surface_ack_configure(xdgSurface, serial);
+    state.configured = true;
+  }
+}
+
+static const struct xdg_surface_listener xdgSurfaceListener = {
+  .configure = xdgSurfaceConfigure,
+};
+
+// XDG Toplevel listeners.
+
+static void xdgToplevelConfigure(void * data, struct xdg_toplevel * xdgToplevel,
+    int32_t width, int32_t height, struct wl_array * states)
+{
+  state.width      = width;
+  state.height     = height;
+  state.fullscreen = false;
+  state.floating   = true;
+
+  enum xdg_toplevel_state * s;
+  wl_array_for_each(s, states)
+  {
+    switch (*s)
+    {
+      case XDG_TOPLEVEL_STATE_FULLSCREEN:
+        state.fullscreen = true;
+        // fallthrough
+      case XDG_TOPLEVEL_STATE_MAXIMIZED:
+      case XDG_TOPLEVEL_STATE_TILED_LEFT:
+      case XDG_TOPLEVEL_STATE_TILED_RIGHT:
+      case XDG_TOPLEVEL_STATE_TILED_TOP:
+      case XDG_TOPLEVEL_STATE_TILED_BOTTOM:
+        state.floating = false;
+        break;
+
+      default:
+        break;
+    }
+  }
+}
+
+static void xdgToplevelClose(void * data, struct xdg_toplevel * xdgToplevel)
+{
+  app_handleCloseEvent();
+}
+
+static const struct xdg_toplevel_listener xdgToplevelListener = {
+  .configure = xdgToplevelConfigure,
+  .close     = xdgToplevelClose,
+};
+
+bool xdg_shellInit(struct wl_display * display, struct wl_surface * surface,
+    const char * title, bool fullscreen, bool maximize, bool borderless,
+    bool resizable)
+{
+  if (!state.wmBase)
+  {
+    DEBUG_ERROR("Compositor missing xdg_wm_base, will not proceed");
+    return false;
+  }
+
+  xdg_wm_base_add_listener(state.wmBase, &xdgWmBaseListener, NULL);
+
+  state.surface = xdg_wm_base_get_xdg_surface(state.wmBase, surface);
+  xdg_surface_add_listener(state.surface, &xdgSurfaceListener, NULL);
+
+  state.toplevel = xdg_surface_get_toplevel(state.surface);
+  xdg_toplevel_add_listener(state.toplevel, &xdgToplevelListener, NULL);
+  xdg_toplevel_set_title(state.toplevel, title);
+  xdg_toplevel_set_app_id(state.toplevel, "looking-glass-client");
+
+  if (fullscreen)
+    xdg_toplevel_set_fullscreen(state.toplevel, NULL);
+
+  if (maximize)
+    xdg_toplevel_set_maximized(state.toplevel);
+
+  if (state.decorationManager)
+  {
+    state.toplevelDecoration = zxdg_decoration_manager_v1_get_toplevel_decoration(
+        state.decorationManager, state.toplevel);
+    if (state.toplevelDecoration)
+    {
+      zxdg_toplevel_decoration_v1_set_mode(state.toplevelDecoration,
+          borderless ?
+            ZXDG_TOPLEVEL_DECORATION_V1_MODE_CLIENT_SIDE :
+            ZXDG_TOPLEVEL_DECORATION_V1_MODE_SERVER_SIDE);
+    }
+  }
+
+  return true;
+}
+
+static void xdg_shellAckConfigureIfNeeded(void)
+{
+  if (state.resizeSerial)
+  {
+    xdg_surface_ack_configure(state.surface, state.resizeSerial);
+    state.resizeSerial = 0;
+  }
+}
+
+static void xdg_setFullscreen(bool fs)
+{
+  if (fs)
+    xdg_toplevel_set_fullscreen(state.toplevel, NULL);
+  else
+    xdg_toplevel_unset_fullscreen(state.toplevel);
+}
+
+static bool xdg_getFullscreen(void)
+{
+  return state.fullscreen;
+}
+
+static void xdg_minimize(void)
+{
+  xdg_toplevel_set_minimized(state.toplevel);
+}
+
+static void xdg_shellResize(int w, int h)
+{
+  if (!state.floating)
+    return;
+
+  state.width  = w;
+  state.height = h;
+  xdg_surface_set_window_geometry(state.surface, 0, 0, w, h);
+
+  waylandNeedsResize();
+}
+
+static void xdg_setSize(int w, int h)
+{
+  state.width  = w;
+  state.height = h;
+}
+
+static void xdg_getSize(int * w, int * h)
+{
+  *w = state.width;
+  *h = state.height;
+}
+
+static bool xdg_registryGlobalHandler(void * data,
+    struct wl_registry * registry, uint32_t name, const char * interface,
+    uint32_t version)
+{
+  if (!strcmp(interface, xdg_wm_base_interface.name))
+  {
+    state.wmBase = wl_registry_bind(registry, name,
+        &xdg_wm_base_interface, 1);
+    return true;
+  }
+
+  if (!strcmp(interface, zxdg_decoration_manager_v1_interface.name))
+  {
+    state.decorationManager = wl_registry_bind(registry, name,
+        &zxdg_decoration_manager_v1_interface, 1);
+    return true;
+  }
+
+  return false;
+}
+
+static void waylandDisplayCallback(uint32_t events, void * opaque)
+{
+  struct wl_display * display = (struct wl_display *)opaque;
+  if (events & EPOLLERR)
+    wl_display_cancel_read(display);
+  else
+    wl_display_read_events(display);
+  wl_display_dispatch_pending(display);
+}
+
+static bool xdg_pollInit(struct wl_display * display)
+{
+  state.displayFd = wl_display_get_fd(display);
+  if (!waylandPollRegister(state.displayFd, waylandDisplayCallback,
+        display, EPOLLIN))
+  {
+    DEBUG_ERROR("Failed register display to epoll: %s", strerror(errno));
+    return false;
+  }
+
+  return true;
+}
+
+void xdg_pollWait(struct wl_display * display, int epollFd,
+    unsigned int time)
+{
+  while (wl_display_prepare_read(display))
+    wl_display_dispatch_pending(display);
+  wl_display_flush(display);
+
+  struct epoll_event events[MAX_EPOLL_EVENTS];
+  int count;
+  if ((count = epoll_wait(epollFd, events, MAX_EPOLL_EVENTS, time)) < 0)
+  {
+    if (errno != EINTR)
+      DEBUG_INFO("epoll failed: %s", strerror(errno));
+    wl_display_cancel_read(display);
+    return;
+  }
+
+  bool sawDisplay = false;
+  for (int i = 0; i < count; ++i) {
+    struct WaylandPoll * poll = events[i].data.ptr;
+    if (!poll->removed)
+      poll->callback(events[i].events, poll->opaque);
+    if (poll->fd == state.displayFd)
+      sawDisplay = true;
+  }
+
+  if (!sawDisplay)
+    wl_display_cancel_read(display);
+}
+
+WL_DesktopOps WLD_xdg =
+{
+  .name                      = "xdg",
+  .compositor                = "",
+  .shellInit                 = xdg_shellInit,
+  .shellAckConfigureIfNeeded = xdg_shellAckConfigureIfNeeded,
+  .setFullscreen             = xdg_setFullscreen,
+  .getFullscreen             = xdg_getFullscreen,
+  .minimize                  = xdg_minimize,
+  .shellResize               = xdg_shellResize,
+  .setSize                   = xdg_setSize,
+  .getSize                   = xdg_getSize,
+  .registryGlobalHandler     = xdg_registryGlobalHandler,
+  .pollInit                  = xdg_pollInit,
+  .pollWait                  = xdg_pollWait
+};