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x11: Support using xcb-keysyms as fallback for XKB
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Massage the parts from #303 which deal with input using xcb-keysyms to
be included in the x11 platform plug-in. This provides a fallback that
can be used when XKB initialization fails, typically in cases where the
X server does not support XKB or has the support disabled. XKB is a X11
protocol extension after all, and it is wrong to assume that it will be
always available.
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@aperezdc
aperezdc committed Nov 30, 2023
1 parent d1fbcb7 commit 27c30fb
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Showing 2 changed files with 150 additions and 55 deletions.
174 changes: 129 additions & 45 deletions platform/x11/cog-platform-x11.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -18,6 +18,11 @@
#include <X11/Xlib.h>
#include <xcb/xcb.h>
#include <xcb/xcb_cursor.h>

#ifdef COG_X11_USE_XCB_KEYSYMS
# include <xcb/xcb_keysyms.h>
#endif /* COG_X11_USE_XCB_KEYSYMS */

#include <xkbcommon/xkbcommon-x11.h>

#if COG_HAVE_LIBPORTAL
Expand Down Expand Up @@ -94,6 +99,10 @@ struct CogX11Display {
xkb_mod_mask_t caps_lock;
} xkb;

#ifdef COG_X11_USE_XCB_KEYSYMS
xcb_key_symbols_t *xcb_keysyms;
#endif /* COG_X11_USE_XCB_KEYSYMS */

struct {
PFNEGLGETPLATFORMDISPLAYEXTPROC get_platform_display;

Expand Down Expand Up @@ -212,35 +221,84 @@ xcb_update_xkb_modifiers(uint32_t event_state)
return wpe_modifiers;
}

#if COG_X11_USE_XCB_KEYSYMS
/*
* Convert XCB modifiers to WPE modifiers
*
* - wpe constants from <wpe/input.h>,
* - XCB constants from <xcb/xproto.h>
*
* Far from ideal implementation, but it avoids the need to link
* with xcb-keysyms (which is not often packaged by linux distributions)
* or requiring the X11/XKB extension (which is not always available, e.g.
* in VNC).
*/
static uint32_t
xcb_state_to_wpe_modifiers(uint16_t xcb_state)
{
uint32_t out = 0;

/* SHIFT, CONTROL, ALT/META keys */
if (xcb_state & XCB_MOD_MASK_SHIFT)
out |= wpe_input_keyboard_modifier_shift;

if (xcb_state & XCB_MOD_MASK_CONTROL)
out |= wpe_input_keyboard_modifier_control;

if (xcb_state & XCB_MOD_MASK_1)
out |= wpe_input_keyboard_modifier_alt;

/* Mouse buttons */
if (xcb_state & XCB_BUTTON_MASK_1)
out |= wpe_input_pointer_modifier_button1;

if (xcb_state & XCB_BUTTON_MASK_2)
out |= wpe_input_pointer_modifier_button2;

if (xcb_state & XCB_BUTTON_MASK_3)
out |= wpe_input_pointer_modifier_button3;

if (xcb_state & XCB_BUTTON_MASK_4)
out |= wpe_input_pointer_modifier_button4;

return out;
}
#endif /* COG_X11_USE_XCB_KEYSYMS */

static void
xcb_handle_key_press(CogView *view, xcb_key_press_event_t *event)
key_event_fill(struct wpe_input_keyboard_event *wpe_event, xcb_key_press_event_t *event)
{
uint32_t modifiers = xcb_update_xkb_modifiers(event->state);
uint32_t keysym = xkb_state_key_get_one_sym(s_display->xkb.state, event->detail);
wpe_event->time = event->time;
wpe_event->hardware_key_code = event->detail;

struct wpe_input_keyboard_event input_event = {
.time = event->time,
.key_code = keysym,
.hardware_key_code = event->detail,
.pressed = true,
.modifiers = modifiers,
};
if (s_display->xkb.device_id >= 0 && s_display->xkb.state) {
wpe_event->modifiers = xcb_update_xkb_modifiers(event->state);
wpe_event->key_code = xkb_state_key_get_one_sym(s_display->xkb.state, event->detail);
return;
}

#if COG_X11_USE_XCB_KEYSYMS
if (s_display->xcb_keysyms) {
wpe_event->modifiers = xcb_state_to_wpe_modifiers(event->state);
wpe_event->key_code = xcb_key_symbols_get_keysym(s_display->xcb_keysyms, event->detail, 0);
return;
}
#endif /* COG_X11_USE_XCB_KEYSYMS */
}

static void
xcb_handle_key_press(CogView *view, xcb_key_press_event_t *event)
{
struct wpe_input_keyboard_event input_event = {.pressed = true};
key_event_fill(&input_event, event);
cog_view_handle_key_event(view, &input_event);
}

static void
xcb_handle_key_release(CogView *view, xcb_key_press_event_t *event)
{
uint32_t modifiers = xcb_update_xkb_modifiers(event->state);
uint32_t keysym = xkb_state_key_get_one_sym(s_display->xkb.state, event->detail);

struct wpe_input_keyboard_event input_event = {
.time = event->time,
.key_code = keysym,
.hardware_key_code = event->detail,
.pressed = false,
.modifiers = modifiers,
};
struct wpe_input_keyboard_event input_event = {.pressed = false};
key_event_fill(&input_event, event);
cog_view_handle_key_event(view, &input_event);
}

Expand Down Expand Up @@ -607,41 +665,72 @@ clear_xcb (void)
static gboolean
init_xkb (void)
{
s_display->xkb.device_id = xkb_x11_get_core_keyboard_device_id (s_display->xcb.connection);
if (s_display->xkb.device_id == -1)
return FALSE;

s_display->xkb.context = xkb_context_new (0);
if (!s_display->xkb.context)
return FALSE;

s_display->xkb.keymap = xkb_x11_keymap_new_from_device (s_display->xkb.context, s_display->xcb.connection, s_display->xkb.device_id, XKB_KEYMAP_COMPILE_NO_FLAGS);
if (!s_display->xkb.keymap)
return FALSE;
if (((s_display->xkb.device_id = xkb_x11_get_core_keyboard_device_id(s_display->xcb.connection)) == -1) ||
!(s_display->xkb.context = xkb_context_new(0)) ||
!(s_display->xkb.keymap =
xkb_x11_keymap_new_from_device(s_display->xkb.context, s_display->xcb.connection,
s_display->xkb.device_id, XKB_KEYMAP_COMPILE_NO_FLAGS)))
goto no_xkb_cleanup;

s_display->xkb.shift = 1 << xkb_keymap_mod_get_index(s_display->xkb.keymap, "Shift");
s_display->xkb.control = 1 << xkb_keymap_mod_get_index(s_display->xkb.keymap, "Control");
s_display->xkb.alt = 1 << xkb_keymap_mod_get_index(s_display->xkb.keymap, "Mod1");
s_display->xkb.caps_lock = 1 << xkb_keymap_mod_get_index(s_display->xkb.keymap, "Lock");
s_display->xkb.num_lock = 1 << xkb_keymap_mod_get_index(s_display->xkb.keymap, "NumLock");

s_display->xkb.state =
xkb_x11_state_new_from_device(s_display->xkb.keymap, s_display->xcb.connection, s_display->xkb.device_id);
if (!s_display->xkb.state)
return FALSE;
if (!(s_display->xkb.state = xkb_x11_state_new_from_device(s_display->xkb.keymap, s_display->xcb.connection,
s_display->xkb.device_id)))
goto no_xkb_cleanup;

return TRUE;

no_xkb_cleanup:
g_clear_pointer(&s_display->xkb.keymap, xkb_keymap_unref);
g_clear_pointer(&s_display->xkb.context, xkb_context_unref);
s_display->xkb.device_id = -1;
return FALSE;
}

static gboolean
init_keyboard(GError **error)
{
g_autoptr(GString) tried_impl = NULL;

if (init_xkb()) {
g_debug("%s: Using XKB", G_STRFUNC);
return TRUE;
}

#ifdef COG_X11_USE_XCB_KEYSYMS
tried_impl = tried_impl ? g_string_append(tried_impl, ", XCB-Keysyms") : g_string_new("XCB-Keysyms");

if ((s_display->xcb_keysyms = xcb_key_symbols_alloc(s_display->xcb.connection))) {
g_debug("%s: Using XCB-Keysyms", G_STRFUNC);
return TRUE;
}
#endif /* COG_X11_USE_XCB_KEYSYMS */

g_set_error(error,
COG_PLATFORM_WPE_ERROR,
COG_PLATFORM_WPE_ERROR_INIT,
"Could not initialize keyboard, tried %s",
tried_impl ? tried_impl->str : "no implementations");
return FALSE;
}

static void
clear_xkb (void)
clear_keyboard(void)
{
if (s_display->xkb.state)
xkb_state_unref (s_display->xkb.state);
if (s_display->xkb.keymap)
xkb_keymap_unref (s_display->xkb.keymap);
if (s_display->xkb.context)
xkb_context_unref (s_display->xkb.context);

#ifdef COG_X11_USE_XCB_KEYSYMS
g_clear_pointer(&s_display->xcb_keysyms, xcb_key_symbols_free);
#endif /* COG_X11_USE_XCB_KEYSYMS */
}

static gboolean
Expand Down Expand Up @@ -798,13 +887,8 @@ cog_x11_platform_setup(CogPlatform *platform, CogShell *shell G_GNUC_UNUSED, con
return FALSE;
}

if (!init_xkb ()) {
g_set_error_literal (error,
COG_PLATFORM_WPE_ERROR,
COG_PLATFORM_WPE_ERROR_INIT,
"Failed to initialize XKB");
if (!init_keyboard(error))
return FALSE;
}

if (!init_egl ()) {
g_set_error_literal (error,
Expand Down Expand Up @@ -842,9 +926,9 @@ cog_x11_platform_finalize(GObject *object)
{
clear_glib ();
cog_gl_renderer_finalize(&s_display->gl_render);
clear_egl ();
clear_xkb ();
clear_xcb ();
clear_egl();
clear_keyboard();
clear_xcb();

g_clear_pointer (&s_window, free);
g_clear_pointer (&s_display, free);
Expand Down
31 changes: 21 additions & 10 deletions platform/x11/meson.build
View file
Original file line number Diff line number Diff line change
Expand Up @@ -3,19 +3,30 @@ if libportal_dep.found()
x11_platform_sources += ['cog-xdp-parent-x11.c']
endif

x11_platform_c_args = platform_c_args + [
'-DG_LOG_DOMAIN="Cog-X11"',
]
x11_platform_dependencies = [
wpebackend_fdo_dep,
cogplatformcommon_dep,
dependency('egl'),
dependency('xcb'),
dependency('xkbcommon-x11'),
dependency('x11-xcb'),
dependency('xcb-cursor'),
]

xcb_keysyms_dep = dependency('xcb-keysyms', required: false)
if xcb_keysyms_dep.found()
x11_platform_dependencies += [xcb_keysyms_dep]
x11_platform_c_args += ['-DCOG_X11_USE_XCB_KEYSYMS']
endif

x11_platform_plugin = shared_module('cogplatform-x11',
'cog-platform-x11.c',
x11_platform_sources,
c_args: platform_c_args + ['-DG_LOG_DOMAIN="Cog-X11"'],
dependencies: [
wpebackend_fdo_dep,
cogplatformcommon_dep,
dependency('egl'),
dependency('xcb'),
dependency('xkbcommon-x11'),
dependency('x11-xcb'),
dependency('xcb-cursor'),
],
c_args: x11_platform_c_args,
dependencies: x11_platform_dependencies,
gnu_symbol_visibility: 'hidden',
install_dir: plugin_path,
install: true,
Expand Down

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