Jelajahi Sumber

Add XSETTINGS support to x11 driver

Import the XSettingsClient implementation to handle the settings
selection.

Currently, we only care about the Gdk/WindowScalingFactor value used by
the windowing system to notify us of display-wide changes in the scaling
factor.
Emmanuele Bassi 1 tahun lalu
induk
melakukan
61dafb3b2f

+ 4 - 1
cmake/3rdparty.cmake

@@ -104,7 +104,10 @@ function(get_clang_tidy_ignored_files OUTVAR)
       "hid.m"
       "hidraw.cpp"
       "hidusb.cpp"
-      "hidapi.h")
+      "hidapi.h"
+      # XSETTINGS
+      "xsettings-client.c"
+      "xsettings-client.h")
 
   foreach(SOURCE_FILE ${3RD_PARTY_SOURCES})
     list(APPEND IGNORED_LIST "{\"name\":\"${SOURCE_FILE}\",\"lines\":[[1,1]]}")

+ 17 - 0
src/video/x11/SDL_x11events.c

@@ -33,6 +33,7 @@
 #include "SDL_x11touch.h"
 #include "SDL_x11xinput2.h"
 #include "SDL_x11xfixes.h"
+#include "SDL_x11settings.h"
 #include "../SDL_clipboard_c.h"
 #include "../../core/unix/SDL_poll.h"
 #include "../../events/SDL_events_c.h"
@@ -779,6 +780,16 @@ static void X11_HandleClipboardEvent(SDL_VideoDevice *_this, const XEvent *xeven
     }
 }
 
+static void X11_HandleSettingsEvent(SDL_VideoDevice *_this, const XEvent *xevent)
+{
+    SDL_VideoData *videodata = _this->driverdata;
+
+    SDL_assert(videodata->xsettings_window != None);
+    SDL_assert(xevent->xany.window == videodata->xsettings_window);
+
+    X11_HandleXsettings(_this, xevent);
+}
+
 static Bool isMapNotify(Display *display, XEvent *ev, XPointer arg)
 {
     XUnmapEvent *unmap;
@@ -1103,6 +1114,12 @@ static void X11_DispatchEvent(SDL_VideoDevice *_this, XEvent *xevent)
         return;
     }
 
+    if ((videodata->xsettings_window != None) &&
+        (videodata->xsettings_window == xevent->xany.window)) {
+        X11_HandleSettingsEvent(_this, xevent);
+        return;
+    }
+
     data = X11_FindWindow(_this, xevent->xany.window);
 
     if (!data) {

+ 97 - 0
src/video/x11/SDL_x11settings.c

@@ -0,0 +1,97 @@
+/*
+  Simple DirectMedia Layer
+  Copyright 2024 Igalia S.L.
+
+  This software is provided 'as-is', without any express or implied
+  warranty.  In no event will the authors be held liable for any damages
+  arising from the use of this software.
+
+  Permission is granted to anyone to use this software for any purpose,
+  including commercial applications, and to alter it and redistribute it
+  freely, subject to the following restrictions:
+
+  1. The origin of this software must not be misrepresented; you must not
+     claim that you wrote the original software. If you use this software
+     in a product, an acknowledgment in the product documentation would be
+     appreciated but is not required.
+  2. Altered source versions must be plainly marked as such, and must not be
+     misrepresented as being the original software.
+  3. This notice may not be removed or altered from any source distribution.
+*/
+
+#include "SDL_internal.h"
+
+#if defined(SDL_VIDEO_DRIVER_X11)
+
+#include "SDL_x11video.h"
+#include "SDL_x11settings.h"
+
+#define SDL_XSETTINGS_GDK_WINDOW_SCALING_FACTOR "Gdk/WindowScalingFactor"
+
+static void X11_XsettingsNotify(const char *name, XSettingsAction action, XSettingsSetting *setting, void *data)
+{
+    SDL_VideoDevice *_this = data;
+    float scale_factor = 1.0;
+    int i;
+
+    if (SDL_strcmp(name, SDL_XSETTINGS_GDK_WINDOW_SCALING_FACTOR) != 0) {
+        return;
+    }
+
+    if (setting->type != XSETTINGS_TYPE_INT) {
+        return;
+    }
+
+    switch (action) {
+    case XSETTINGS_ACTION_NEW:
+        SDL_FALLTHROUGH;
+    case XSETTINGS_ACTION_CHANGED:
+        scale_factor = setting->data.v_int;
+        break;
+    case XSETTINGS_ACTION_DELETED:
+        scale_factor = 1.0;
+        break;
+    }
+
+    if (_this) {
+        for (i = 0; i < _this->num_displays; ++i) {
+            SDL_SetDisplayContentScale(_this->displays[i], scale_factor);
+        }
+    }
+}
+
+void X11_InitXsettings(SDL_VideoDevice *_this)
+{
+    SDL_VideoData *data = _this->driverdata;
+    SDLX11_SettingsData *xsettings_data = &data->xsettings_data;
+
+    xsettings_data->xsettings = xsettings_client_new(data->display,
+        DefaultScreen(data->display), X11_XsettingsNotify, NULL, _this);
+
+}
+
+void X11_QuitXsettings(SDL_VideoDevice *_this)
+{
+    SDL_VideoData *data = _this->driverdata;
+    SDLX11_SettingsData *xsettings_data = &data->xsettings_data;
+
+    if (xsettings_data->xsettings) {
+        xsettings_client_destroy(xsettings_data->xsettings);
+        xsettings_data->xsettings = NULL;
+    }
+}
+
+void X11_HandleXsettings(SDL_VideoDevice *_this, const XEvent *xevent)
+{
+    SDL_VideoData *data = _this->driverdata;
+    SDLX11_SettingsData *xsettings_data = &data->xsettings_data;
+
+    if (xsettings_data->xsettings) {
+        if (!xsettings_client_process_event(xsettings_data->xsettings, xevent)) {
+            xsettings_client_destroy(xsettings_data->xsettings);
+            xsettings_data->xsettings = NULL;
+        }
+    }
+}
+
+#endif /* SDL_VIDEO_DRIVER_X11 */

+ 38 - 0
src/video/x11/SDL_x11settings.h

@@ -0,0 +1,38 @@
+/*
+  Simple DirectMedia Layer
+  Copyright 2024 Igalia S.L.
+
+  This software is provided 'as-is', without any express or implied
+  warranty.  In no event will the authors be held liable for any damages
+  arising from the use of this software.
+
+  Permission is granted to anyone to use this software for any purpose,
+  including commercial applications, and to alter it and redistribute it
+  freely, subject to the following restrictions:
+
+  1. The origin of this software must not be misrepresented; you must not
+     claim that you wrote the original software. If you use this software
+     in a product, an acknowledgment in the product documentation would be
+     appreciated but is not required.
+  2. Altered source versions must be plainly marked as such, and must not be
+     misrepresented as being the original software.
+  3. This notice may not be removed or altered from any source distribution.
+*/
+
+#include "SDL_internal.h"
+
+#ifndef SDL_x11settings_h_
+#define SDL_x11settings_h_
+
+#include <X11/Xlib.h>
+#include "xsettings-client.h"
+
+typedef struct X11_SettingsData {
+    XSettingsClient *xsettings;
+} SDLX11_SettingsData;
+
+extern void X11_InitXsettings(SDL_VideoDevice *_this);
+extern void X11_QuitXsettings(SDL_VideoDevice *_this);
+extern void X11_HandleXsettings(SDL_VideoDevice *_this, const XEvent *xevent);
+
+#endif /* SDL_x11settings_h_ */

+ 7 - 0
src/video/x11/SDL_x11video.c

@@ -443,6 +443,8 @@ int X11_VideoInit(SDL_VideoDevice *_this)
     X11_InitXfixes(_this);
 #endif /* SDL_VIDEO_DRIVER_X11_XFIXES */
 
+    X11_InitXsettings(_this);
+
 #ifndef X_HAVE_UTF8_STRING
 #warning X server does not support UTF8_STRING, a feature introduced in 2000! This is likely to become a hard error in a future libSDL3.
 #endif
@@ -469,6 +471,10 @@ void X11_VideoQuit(SDL_VideoDevice *_this)
         X11_XDestroyWindow(data->display, data->clipboard_window);
     }
 
+    if (data->xsettings_window) {
+        X11_XDestroyWindow(data->display, data->xsettings_window);
+    }
+
 #ifdef X_HAVE_UTF8_STRING
     if (data->im) {
         X11_XCloseIM(data->im);
@@ -480,6 +486,7 @@ void X11_VideoQuit(SDL_VideoDevice *_this)
     X11_QuitMouse(_this);
     X11_QuitTouch(_this);
     X11_QuitClipboard(_this);
+    X11_QuitXsettings(_this);
 }
 
 SDL_bool X11_UseDirectColorVisuals(void)

+ 3 - 0
src/video/x11/SDL_x11video.h

@@ -36,6 +36,7 @@
 #include "SDL_x11modes.h"
 #include "SDL_x11mouse.h"
 #include "SDL_x11opengl.h"
+#include "SDL_x11settings.h"
 #include "SDL_x11window.h"
 #include "SDL_x11vulkan.h"
 
@@ -58,6 +59,8 @@ struct SDL_VideoData
 #ifdef SDL_VIDEO_DRIVER_X11_XFIXES
     SDL_Window *active_cursor_confined_window;
 #endif /* SDL_VIDEO_DRIVER_X11_XFIXES */
+    Window xsettings_window;
+    SDLX11_SettingsData xsettings_data;
 
     /* This is true for ICCCM2.0-compliant window managers */
     SDL_bool net_wm;

+ 855 - 0
src/video/x11/xsettings-client.c

@@ -0,0 +1,855 @@
+/*
+ * Copyright © 2001, 2007 Red Hat, Inc.
+ * Copyright 2024 Igalia S.L.
+ *
+ * Permission to use, copy, modify, distribute, and sell this software and its
+ * documentation for any purpose is hereby granted without fee, provided that
+ * the above copyright notice appear in all copies and that both that
+ * copyright notice and this permission notice appear in supporting
+ * documentation, and that the name of Red Hat not be used in advertising or
+ * publicity pertaining to distribution of the software without specific,
+ * written prior permission.  Red Hat makes no representations about the
+ * suitability of this software for any purpose.  It is provided "as is"
+ * without express or implied warranty.
+ *
+ * RED HAT DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO EVENT SHALL RED HAT
+ * BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
+ * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
+ * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ * Author:  Owen Taylor, Red Hat, Inc.
+ */
+
+#include "SDL_internal.h"
+
+#ifdef SDL_VIDEO_DRIVER_X11
+
+#include "SDL_x11video.h"
+
+#include <limits.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "xsettings-client.h"
+
+struct _XSettingsClient
+{
+  Display *display;
+  int screen;
+  XSettingsNotifyFunc notify;
+  XSettingsWatchFunc watch;
+  void *cb_data;
+
+  XSettingsGrabFunc grab;
+  XSettingsGrabFunc ungrab;
+
+  Window manager_window;
+  Atom manager_atom;
+  Atom selection_atom;
+  Atom xsettings_atom;
+
+  XSettingsList *settings;
+};
+
+static void
+notify_changes (XSettingsClient *client,
+                XSettingsList   *old_list)
+{
+  XSettingsList *old_iter = old_list;
+  XSettingsList *new_iter = client->settings;
+
+  if (!client->notify)
+    return;
+
+  while (old_iter || new_iter)
+    {
+      int cmp;
+
+      if (old_iter && new_iter)
+        cmp = strcmp (old_iter->setting->name, new_iter->setting->name);
+      else if (old_iter)
+        cmp = -1;
+      else
+        cmp = 1;
+
+      if (cmp < 0)
+        {
+          client->notify (old_iter->setting->name,
+                          XSETTINGS_ACTION_DELETED,
+                          NULL,
+                          client->cb_data);
+        }
+      else if (cmp == 0)
+        {
+          if (!xsettings_setting_equal (old_iter->setting,
+                                        new_iter->setting))
+            client->notify (old_iter->setting->name,
+                            XSETTINGS_ACTION_CHANGED,
+                            new_iter->setting,
+                            client->cb_data);
+        }
+      else
+        {
+          client->notify (new_iter->setting->name,
+                          XSETTINGS_ACTION_NEW,
+                          new_iter->setting,
+                          client->cb_data);
+        }
+
+      if (old_iter)
+        old_iter = old_iter->next;
+      if (new_iter)
+        new_iter = new_iter->next;
+    }
+}
+
+static int
+ignore_errors (Display *display, XErrorEvent *event)
+{
+  return True;
+}
+
+static char local_byte_order = '\0';
+
+#define BYTES_LEFT(buffer) ((buffer)->data + (buffer)->len - (buffer)->pos)
+
+static XSettingsResult
+fetch_card16 (XSettingsBuffer *buffer,
+              CARD16          *result)
+{
+  CARD16 x;
+
+  if (BYTES_LEFT (buffer) < 2)
+    return XSETTINGS_ACCESS;
+
+  x = *(CARD16 *)buffer->pos;
+  buffer->pos += 2;
+
+  if (buffer->byte_order == local_byte_order)
+    *result = x;
+  else
+    *result = (x << 8) | (x >> 8);
+
+  return XSETTINGS_SUCCESS;
+}
+
+static XSettingsResult
+fetch_ushort (XSettingsBuffer *buffer,
+              unsigned short  *result)
+{
+  CARD16 x;
+  XSettingsResult r;
+
+  r = fetch_card16 (buffer, &x);
+  if (r == XSETTINGS_SUCCESS)
+    *result = x;
+
+  return r;
+}
+
+static XSettingsResult
+fetch_card32 (XSettingsBuffer *buffer,
+              CARD32          *result)
+{
+  CARD32 x;
+
+  if (BYTES_LEFT (buffer) < 4)
+    return XSETTINGS_ACCESS;
+
+  x = *(CARD32 *)buffer->pos;
+  buffer->pos += 4;
+
+  if (buffer->byte_order == local_byte_order)
+    *result = x;
+  else
+    *result = (x << 24) | ((x & 0xff00) << 8) | ((x & 0xff0000) >> 8) | (x >> 24);
+
+  return XSETTINGS_SUCCESS;
+}
+
+static XSettingsResult
+fetch_card8 (XSettingsBuffer *buffer,
+             CARD8           *result)
+{
+  if (BYTES_LEFT (buffer) < 1)
+    return XSETTINGS_ACCESS;
+
+  *result = *(CARD8 *)buffer->pos;
+  buffer->pos += 1;
+
+  return XSETTINGS_SUCCESS;
+}
+
+#define XSETTINGS_PAD(n,m) ((n + m - 1) & (~(m-1)))
+
+static XSettingsList *
+parse_settings (unsigned char *data,
+                size_t         len)
+{
+  XSettingsBuffer buffer;
+  XSettingsResult result = XSETTINGS_SUCCESS;
+  XSettingsList *settings = NULL;
+  CARD32 serial;
+  CARD32 n_entries;
+  CARD32 i;
+  XSettingsSetting *setting = NULL;
+  char buffer_byte_order = '\0';
+
+  local_byte_order = xsettings_byte_order ();
+
+  buffer.pos = buffer.data = data;
+  buffer.len = len;
+  buffer.byte_order = '\0';
+
+  result = fetch_card8 (&buffer, (unsigned char *) &buffer_byte_order);
+  if (buffer_byte_order != MSBFirst &&
+      buffer_byte_order != LSBFirst)
+    {
+      fprintf (stderr, "Invalid byte order in XSETTINGS property\n");
+      result = XSETTINGS_FAILED;
+      goto out;
+    }
+
+  buffer.byte_order = buffer_byte_order;
+  buffer.pos += 3;
+
+  result = fetch_card32 (&buffer, &serial);
+  if (result != XSETTINGS_SUCCESS)
+    goto out;
+
+  result = fetch_card32 (&buffer, &n_entries);
+  if (result != XSETTINGS_SUCCESS)
+    goto out;
+
+  for (i = 0; i < n_entries; i++)
+    {
+      CARD8 type;
+      CARD16 name_len;
+      CARD32 v_int;
+      size_t pad_len;
+
+      result = fetch_card8 (&buffer, &type);
+      if (result != XSETTINGS_SUCCESS)
+        goto out;
+
+      buffer.pos += 1;
+
+      result = fetch_card16 (&buffer, &name_len);
+      if (result != XSETTINGS_SUCCESS)
+        goto out;
+
+      pad_len = XSETTINGS_PAD(name_len, 4);
+      if (BYTES_LEFT (&buffer) < pad_len)
+        {
+          result = XSETTINGS_ACCESS;
+          goto out;
+        }
+
+      setting = malloc (sizeof *setting);
+      if (!setting)
+        {
+          result = XSETTINGS_NO_MEM;
+          goto out;
+        }
+      setting->type = XSETTINGS_TYPE_INT; /* No allocated memory */
+
+      setting->name = malloc (name_len + 1);
+      if (!setting->name)
+        {
+          result = XSETTINGS_NO_MEM;
+          goto out;
+        }
+
+      memcpy (setting->name, buffer.pos, name_len);
+      setting->name[name_len] = '\0';
+      buffer.pos += pad_len;
+
+      result = fetch_card32 (&buffer, &v_int);
+      if (result != XSETTINGS_SUCCESS)
+        goto out;
+      setting->last_change_serial = v_int;
+
+      switch (type)
+        {
+        case XSETTINGS_TYPE_INT:
+          result = fetch_card32 (&buffer, &v_int);
+          if (result != XSETTINGS_SUCCESS)
+            goto out;
+
+          setting->data.v_int = (INT32)v_int;
+          break;
+        case XSETTINGS_TYPE_STRING:
+          result = fetch_card32 (&buffer, &v_int);
+          if (result != XSETTINGS_SUCCESS)
+            goto out;
+
+          pad_len = XSETTINGS_PAD (v_int, 4);
+          if (v_int + 1 == 0 || /* Guard against wrap-around */
+              BYTES_LEFT (&buffer) < pad_len)
+            {
+              result = XSETTINGS_ACCESS;
+              goto out;
+            }
+
+          setting->data.v_string = malloc (v_int + 1);
+          if (!setting->data.v_string)
+            {
+              result = XSETTINGS_NO_MEM;
+              goto out;
+            }
+
+          memcpy (setting->data.v_string, buffer.pos, v_int);
+          setting->data.v_string[v_int] = '\0';
+          buffer.pos += pad_len;
+
+          break;
+        case XSETTINGS_TYPE_COLOR:
+          result = fetch_ushort (&buffer, &setting->data.v_color.red);
+          if (result != XSETTINGS_SUCCESS)
+            goto out;
+          result = fetch_ushort (&buffer, &setting->data.v_color.green);
+          if (result != XSETTINGS_SUCCESS)
+            goto out;
+          result = fetch_ushort (&buffer, &setting->data.v_color.blue);
+          if (result != XSETTINGS_SUCCESS)
+            goto out;
+          result = fetch_ushort (&buffer, &setting->data.v_color.alpha);
+          if (result != XSETTINGS_SUCCESS)
+            goto out;
+
+          break;
+        default:
+          /* Quietly ignore unknown types */
+          break;
+        }
+
+      setting->type = type;
+
+      result = xsettings_list_insert (&settings, setting);
+      if (result != XSETTINGS_SUCCESS)
+        goto out;
+
+      setting = NULL;
+    }
+
+ out:
+
+  if (result != XSETTINGS_SUCCESS)
+    {
+      switch (result)
+        {
+        case XSETTINGS_NO_MEM:
+          fprintf(stderr, "Out of memory reading XSETTINGS property\n");
+          break;
+        case XSETTINGS_ACCESS:
+          fprintf(stderr, "Invalid XSETTINGS property (read off end)\n");
+          break;
+        case XSETTINGS_DUPLICATE_ENTRY:
+          fprintf (stderr, "Duplicate XSETTINGS entry for '%s'\n", setting->name);
+          SDL_FALLTHROUGH;
+        case XSETTINGS_FAILED:
+          SDL_FALLTHROUGH;
+        case XSETTINGS_SUCCESS:
+          SDL_FALLTHROUGH;
+        case XSETTINGS_NO_ENTRY:
+          break;
+        }
+
+      if (setting)
+        xsettings_setting_free (setting);
+
+      xsettings_list_free (settings);
+      settings = NULL;
+
+    }
+
+  return settings;
+}
+
+static void
+read_settings (XSettingsClient *client)
+{
+  Atom type;
+  int format;
+  unsigned long n_items;
+  unsigned long bytes_after;
+  unsigned char *data;
+  int result;
+
+  int (*old_handler) (Display *, XErrorEvent *);
+
+  XSettingsList *old_list = client->settings;
+
+  client->settings = NULL;
+
+  if (client->manager_window)
+    {
+      old_handler = X11_XSetErrorHandler (ignore_errors);
+      result = X11_XGetWindowProperty (client->display, client->manager_window,
+                                       client->xsettings_atom, 0, LONG_MAX,
+                                       False, client->xsettings_atom,
+                                       &type, &format, &n_items, &bytes_after, &data);
+      X11_XSetErrorHandler (old_handler);
+
+      if (result == Success && type != None)
+        {
+          if (type != client->xsettings_atom)
+            {
+              fprintf (stderr, "Invalid type for XSETTINGS property");
+            }
+          else if (format != 8)
+            {
+              fprintf (stderr, "Invalid format for XSETTINGS property %d", format);
+            }
+          else
+            client->settings = parse_settings (data, n_items);
+
+          X11_XFree (data);
+        }
+    }
+
+  notify_changes (client, old_list);
+  xsettings_list_free (old_list);
+}
+
+static void
+add_events (Display *display,
+            Window   window,
+            long     mask)
+{
+  XWindowAttributes attr;
+
+  X11_XGetWindowAttributes (display, window, &attr);
+  X11_XSelectInput (display, window, attr.your_event_mask | mask);
+}
+
+static void
+check_manager_window (XSettingsClient *client)
+{
+  if (client->manager_window && client->watch)
+    client->watch (client->manager_window, False, 0, client->cb_data);
+
+  if (client->grab)
+    client->grab (client->display);
+  else
+    X11_XGrabServer (client->display);
+
+  client->manager_window = X11_XGetSelectionOwner (client->display,
+                                                   client->selection_atom);
+  if (client->manager_window)
+    X11_XSelectInput (client->display, client->manager_window,
+                      PropertyChangeMask | StructureNotifyMask);
+
+  if (client->ungrab)
+    client->ungrab (client->display);
+  else
+    X11_XUngrabServer (client->display);
+
+  X11_XFlush (client->display);
+
+  if (client->manager_window && client->watch)
+    {
+      if (!client->watch (client->manager_window, True,
+                          PropertyChangeMask | StructureNotifyMask,
+                          client->cb_data))
+        {
+          /* Inability to watch the window probably means that it was destroyed
+           * after we ungrabbed
+           */
+          client->manager_window = None;
+          return;
+        }
+    }
+
+
+  read_settings (client);
+}
+
+XSettingsClient *
+xsettings_client_new (Display             *display,
+                      int                  screen,
+                      XSettingsNotifyFunc  notify,
+                      XSettingsWatchFunc   watch,
+                      void                *cb_data)
+{
+  return xsettings_client_new_with_grab_funcs (display, screen, notify, watch, cb_data,
+                                               NULL, NULL);
+}
+
+XSettingsClient *
+xsettings_client_new_with_grab_funcs (Display             *display,
+                                      int                  screen,
+                                      XSettingsNotifyFunc  notify,
+                                      XSettingsWatchFunc   watch,
+                                      void                *cb_data,
+                                      XSettingsGrabFunc    grab,
+                                      XSettingsGrabFunc    ungrab)
+{
+  XSettingsClient *client;
+  char buffer[256];
+  char *atom_names[3];
+  Atom atoms[3];
+
+  client = malloc (sizeof *client);
+  if (!client)
+    return NULL;
+
+  client->display = display;
+  client->screen = screen;
+  client->notify = notify;
+  client->watch = watch;
+  client->cb_data = cb_data;
+  client->grab = grab;
+  client->ungrab = ungrab;
+
+  client->manager_window = None;
+  client->settings = NULL;
+
+  sprintf(buffer, "_XSETTINGS_S%d", screen);
+  atom_names[0] = buffer;
+  atom_names[1] = "_XSETTINGS_SETTINGS";
+  atom_names[2] = "MANAGER";
+
+#ifdef HAVE_XINTERNATOMS
+  XInternAtoms (display, atom_names, 3, False, atoms);
+#else
+  atoms[0] = X11_XInternAtom (display, atom_names[0], False);
+  atoms[1] = X11_XInternAtom (display, atom_names[1], False);
+  atoms[2] = X11_XInternAtom (display, atom_names[2], False);
+#endif
+
+  client->selection_atom = atoms[0];
+  client->xsettings_atom = atoms[1];
+  client->manager_atom = atoms[2];
+
+  /* Select on StructureNotify so we get MANAGER events
+   */
+  add_events (display, RootWindow (display, screen), StructureNotifyMask);
+
+  if (client->watch)
+    client->watch (RootWindow (display, screen), True, StructureNotifyMask,
+                   client->cb_data);
+
+  check_manager_window (client);
+
+  return client;
+}
+
+
+void
+xsettings_client_set_grab_func   (XSettingsClient      *client,
+                                  XSettingsGrabFunc     grab)
+{
+  client->grab = grab;
+}
+
+void
+xsettings_client_set_ungrab_func (XSettingsClient      *client,
+                                  XSettingsGrabFunc     ungrab)
+{
+  client->ungrab = ungrab;
+}
+
+void
+xsettings_client_destroy (XSettingsClient *client)
+{
+  if (client->watch)
+    client->watch (RootWindow (client->display, client->screen),
+                   False, 0, client->cb_data);
+  if (client->manager_window && client->watch)
+    client->watch (client->manager_window, False, 0, client->cb_data);
+
+  xsettings_list_free (client->settings);
+  free (client);
+}
+
+XSettingsResult
+xsettings_client_get_setting (XSettingsClient   *client,
+                              const char        *name,
+                              XSettingsSetting **setting)
+{
+  XSettingsSetting *search = xsettings_list_lookup (client->settings, name);
+  if (search)
+    {
+      *setting = xsettings_setting_copy (search);
+      return *setting ? XSETTINGS_SUCCESS : XSETTINGS_NO_MEM;
+    }
+  else
+    return XSETTINGS_NO_ENTRY;
+}
+
+Bool
+xsettings_client_process_event (XSettingsClient *client,
+                                const XEvent    *xev)
+{
+  /* The checks here will not unlikely cause us to reread
+   * the properties from the manager window a number of
+   * times when the manager changes from A->B. But manager changes
+   * are going to be pretty rare.
+   */
+  if (xev->xany.window == RootWindow (client->display, client->screen))
+    {
+      if (xev->xany.type == ClientMessage &&
+          xev->xclient.message_type == client->manager_atom &&
+          xev->xclient.data.l[1] == client->selection_atom)
+        {
+          check_manager_window (client);
+          return True;
+        }
+    }
+  else if (xev->xany.window == client->manager_window)
+    {
+      if (xev->xany.type == DestroyNotify)
+        {
+          check_manager_window (client);
+          return False;
+        }
+      else if (xev->xany.type == PropertyNotify)
+        {
+          read_settings (client);
+          return True;
+        }
+    }
+
+  return False;
+}
+
+XSettingsSetting *
+xsettings_setting_copy (XSettingsSetting *setting)
+{
+  XSettingsSetting *result;
+  size_t str_len;
+
+  result = malloc (sizeof *result);
+  if (!result)
+    return NULL;
+
+  str_len = strlen (setting->name);
+  result->name = malloc (str_len + 1);
+  if (!result->name)
+    goto err;
+
+  memcpy (result->name, setting->name, str_len + 1);
+
+  result->type = setting->type;
+
+  switch (setting->type)
+    {
+    case XSETTINGS_TYPE_INT:
+      result->data.v_int = setting->data.v_int;
+      break;
+    case XSETTINGS_TYPE_COLOR:
+      result->data.v_color = setting->data.v_color;
+      break;
+    case XSETTINGS_TYPE_STRING:
+      str_len = strlen (setting->data.v_string);
+      result->data.v_string = malloc (str_len + 1);
+      if (!result->data.v_string)
+        goto err;
+
+      memcpy (result->data.v_string, setting->data.v_string, str_len + 1);
+      break;
+    }
+
+  result->last_change_serial = setting->last_change_serial;
+
+  return result;
+
+ err:
+  if (result->name)
+    free (result->name);
+  free (result);
+
+  return NULL;
+}
+
+XSettingsList *
+xsettings_list_copy (XSettingsList *list)
+{
+  XSettingsList *new = NULL;
+  XSettingsList *old_iter = list;
+  XSettingsList *new_iter = NULL;
+
+  while (old_iter)
+    {
+      XSettingsList *new_node;
+
+      new_node = malloc (sizeof *new_node);
+      if (!new_node)
+        goto error;
+
+      new_node->setting = xsettings_setting_copy (old_iter->setting);
+      if (!new_node->setting)
+        {
+          free (new_node);
+          goto error;
+        }
+
+      if (new_iter)
+        new_iter->next = new_node;
+      else
+        new = new_node;
+
+      new_iter = new_node;
+
+      old_iter = old_iter->next;
+    }
+
+  return new;
+
+ error:
+  xsettings_list_free (new);
+  return NULL;
+}
+
+int
+xsettings_setting_equal (XSettingsSetting *setting_a,
+                         XSettingsSetting *setting_b)
+{
+  if (setting_a->type != setting_b->type)
+    return 0;
+
+  if (strcmp (setting_a->name, setting_b->name) != 0)
+    return 0;
+
+  switch (setting_a->type)
+    {
+    case XSETTINGS_TYPE_INT:
+      return setting_a->data.v_int == setting_b->data.v_int;
+    case XSETTINGS_TYPE_COLOR:
+      return (setting_a->data.v_color.red == setting_b->data.v_color.red &&
+              setting_a->data.v_color.green == setting_b->data.v_color.green &&
+              setting_a->data.v_color.blue == setting_b->data.v_color.blue &&
+              setting_a->data.v_color.alpha == setting_b->data.v_color.alpha);
+    case XSETTINGS_TYPE_STRING:
+      return strcmp (setting_a->data.v_string, setting_b->data.v_string) == 0;
+    }
+
+  return 0;
+}
+
+void
+xsettings_setting_free (XSettingsSetting *setting)
+{
+  if (setting->type == XSETTINGS_TYPE_STRING)
+    free (setting->data.v_string);
+
+  if (setting->name)
+    free (setting->name);
+
+  free (setting);
+}
+
+void
+xsettings_list_free (XSettingsList *list)
+{
+  while (list)
+    {
+      XSettingsList *next = list->next;
+
+      xsettings_setting_free (list->setting);
+      free (list);
+
+      list = next;
+    }
+}
+
+XSettingsResult
+xsettings_list_insert (XSettingsList    **list,
+                       XSettingsSetting  *setting)
+{
+  XSettingsList *node;
+  XSettingsList *iter;
+  XSettingsList *last = NULL;
+
+  node = malloc (sizeof *node);
+  if (!node)
+    return XSETTINGS_NO_MEM;
+  node->setting = setting;
+
+  iter = *list;
+  while (iter)
+    {
+      int cmp = strcmp (setting->name, iter->setting->name);
+
+      if (cmp < 0)
+        break;
+      else if (cmp == 0)
+        {
+          free (node);
+          return XSETTINGS_DUPLICATE_ENTRY;
+        }
+
+      last = iter;
+      iter = iter->next;
+    }
+
+  if (last)
+    last->next = node;
+  else
+    *list = node;
+
+  node->next = iter;
+
+  return XSETTINGS_SUCCESS;
+}
+
+XSettingsResult
+xsettings_list_delete (XSettingsList **list,
+                       const char     *name)
+{
+  XSettingsList *iter;
+  XSettingsList *last = NULL;
+
+  iter = *list;
+  while (iter)
+    {
+      if (strcmp (name, iter->setting->name) == 0)
+        {
+          if (last)
+            last->next = iter->next;
+          else
+            *list = iter->next;
+
+          xsettings_setting_free (iter->setting);
+          free (iter);
+
+          return XSETTINGS_SUCCESS;
+        }
+
+      last = iter;
+      iter = iter->next;
+    }
+
+  return XSETTINGS_FAILED;
+}
+
+XSettingsSetting *
+xsettings_list_lookup (XSettingsList *list,
+                       const char    *name)
+{
+  XSettingsList *iter;
+
+  iter = list;
+  while (iter)
+    {
+      if (strcmp (name, iter->setting->name) == 0)
+        return iter->setting;
+
+      iter = iter->next;
+    }
+
+  return NULL;
+}
+
+char
+xsettings_byte_order (void)
+{
+  CARD32 myint = 0x01020304;
+  return (*(char *)&myint == 1) ? MSBFirst : LSBFirst;
+}
+
+#endif /* SDL_VIDEO_DRIVER_X11 */

+ 153 - 0
src/video/x11/xsettings-client.h

@@ -0,0 +1,153 @@
+/*
+ * Copyright © 2001, 2007 Red Hat, Inc.
+ * Copyright 2024 Igalia S.L.
+ *
+ * Permission to use, copy, modify, distribute, and sell this software and its
+ * documentation for any purpose is hereby granted without fee, provided that
+ * the above copyright notice appear in all copies and that both that
+ * copyright notice and this permission notice appear in supporting
+ * documentation, and that the name of Red Hat not be used in advertising or
+ * publicity pertaining to distribution of the software without specific,
+ * written prior permission.  Red Hat makes no representations about the
+ * suitability of this software for any purpose.  It is provided "as is"
+ * without express or implied warranty.
+ *
+ * RED HAT DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO EVENT SHALL RED HAT
+ * BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
+ * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
+ * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ * Author:  Owen Taylor, Red Hat, Inc.
+ */
+#ifndef XSETTINGS_CLIENT_H
+#define XSETTINGS_CLIENT_H
+
+#ifdef __cplusplus
+extern "C" {
+#endif /* __cplusplus */
+
+typedef struct _XSettingsBuffer  XSettingsBuffer;
+typedef struct _XSettingsColor   XSettingsColor;
+typedef struct _XSettingsList    XSettingsList;
+typedef struct _XSettingsSetting XSettingsSetting;
+
+/* Types of settings possible. Enum values correspond to
+ * protocol values.
+ */
+typedef enum
+{
+  XSETTINGS_TYPE_INT     = 0,
+  XSETTINGS_TYPE_STRING  = 1,
+  XSETTINGS_TYPE_COLOR   = 2
+} XSettingsType;
+
+typedef enum
+{
+  XSETTINGS_SUCCESS,
+  XSETTINGS_NO_MEM,
+  XSETTINGS_ACCESS,
+  XSETTINGS_FAILED,
+  XSETTINGS_NO_ENTRY,
+  XSETTINGS_DUPLICATE_ENTRY
+} XSettingsResult;
+
+struct _XSettingsBuffer
+{
+  char byte_order;
+  size_t len;
+  unsigned char *data;
+  unsigned char *pos;
+};
+
+struct _XSettingsColor
+{
+  unsigned short red, green, blue, alpha;
+};
+
+struct _XSettingsList
+{
+  XSettingsSetting *setting;
+  XSettingsList *next;
+};
+
+struct _XSettingsSetting
+{
+  char *name;
+  XSettingsType type;
+
+  union {
+    int v_int;
+    char *v_string;
+    XSettingsColor v_color;
+  } data;
+
+  unsigned long last_change_serial;
+};
+
+XSettingsSetting *xsettings_setting_copy  (XSettingsSetting *setting);
+void              xsettings_setting_free  (XSettingsSetting *setting);
+int               xsettings_setting_equal (XSettingsSetting *setting_a,
+                                           XSettingsSetting *setting_b);
+
+void              xsettings_list_free   (XSettingsList     *list);
+XSettingsList    *xsettings_list_copy   (XSettingsList     *list);
+XSettingsResult   xsettings_list_insert (XSettingsList    **list,
+                                         XSettingsSetting  *setting);
+XSettingsSetting *xsettings_list_lookup (XSettingsList     *list,
+                                         const char        *name);
+XSettingsResult   xsettings_list_delete (XSettingsList    **list,
+                                         const char        *name);
+
+char xsettings_byte_order (void);
+
+#define XSETTINGS_PAD(n,m) ((n + m - 1) & (~(m-1)))
+
+typedef struct _XSettingsClient XSettingsClient;
+
+typedef enum
+{
+  XSETTINGS_ACTION_NEW,
+  XSETTINGS_ACTION_CHANGED,
+  XSETTINGS_ACTION_DELETED
+} XSettingsAction;
+
+typedef void (*XSettingsNotifyFunc) (const char       *name,
+                                     XSettingsAction   action,
+                                     XSettingsSetting *setting,
+                                     void             *cb_data);
+typedef Bool (*XSettingsWatchFunc)  (Window            window,
+                                     Bool              is_start,
+                                     long              mask,
+                                     void             *cb_data);
+typedef void (*XSettingsGrabFunc)   (Display          *display);
+
+XSettingsClient *xsettings_client_new             (Display             *display,
+                                                   int                  screen,
+                                                   XSettingsNotifyFunc  notify,
+                                                   XSettingsWatchFunc   watch,
+                                                   void                *cb_data);
+XSettingsClient *xsettings_client_new_with_grab_funcs (Display             *display,
+                                                       int                  screen,
+                                                       XSettingsNotifyFunc  notify,
+                                                       XSettingsWatchFunc   watch,
+                                                       void                *cb_data,
+                                                       XSettingsGrabFunc    grab,
+                                                       XSettingsGrabFunc    ungrab);
+void             xsettings_client_set_grab_func   (XSettingsClient     *client,
+                                                   XSettingsGrabFunc    grab);
+void             xsettings_client_set_ungrab_func (XSettingsClient     *client,
+                                                   XSettingsGrabFunc    ungrab);
+void             xsettings_client_destroy         (XSettingsClient     *client);
+Bool             xsettings_client_process_event   (XSettingsClient     *client,
+                                                   const XEvent        *xev);
+XSettingsResult  xsettings_client_get_setting     (XSettingsClient     *client,
+                                                   const char          *name,
+                                                   XSettingsSetting   **setting);
+
+#ifdef __cplusplus
+}
+#endif /* __cplusplus */
+
+#endif /* XSETTINGS_CLIENT_H */