unicode-mode: move state from seat to term

This fixes an issue where entering unicode-mode in one foot client,
also enabled unicode-mode on other foot clients. Both
visually (although glitchy), and in effect.

The reason the state was originally in the seat objects, was to fully
support multi-seat. That is, one seat/keyboard entering unicode-mode
should not affect other seats/keyboards.

The issue with this is that seat objects are Wayland global. Thus, in
server mode, all seat objects are shared between the foot clients.

There is a similarity with IME, which also keeps state in the
seat. There's one big difference, however, and that is IME has Wayland
native enter/leave events, that the compositor emits when windows are
focused/unfocused. These events allow us to reset IME state. For our
own Unicode mode, there is nothing similar.

This patch moves the Unicode state from seats, to the terminal
struct. This does mean that if one seat/keyboard enters Unicode mode,
then *all* seats/keyboards will affect the unicode state. This
potential downside is outweighed by the fact that different foot
clients no longer affect each other.

Closes #1717

CHANGELOG.md

@@ -85,8 +85,11 @@
   monitor's DPI is 0 (this is true for, for example, nested Wayland
   sessions, or in virtualized environments).
 * No error response for empty `XTGETTCAP` request ([#1694][1694]).
+* Unicode-mode in one foot client affecting other clients, in foot
+  server mode ([#1717][1717]).
 
 [1694]: https://codeberg.org/dnkl/foot/issues/1694
+[1717]: https://codeberg.org/dnkl/foot/issues/1717
 
 
 ### Security

input.c

@@ -441,7 +441,7 @@ execute_binding(struct seat *seat, struct terminal *term,
     }
 
     case BIND_ACTION_UNICODE_INPUT:
-        unicode_mode_activate(seat);
+        unicode_mode_activate(term);
         return true;
 
     case BIND_ACTION_QUIT:
@@ -1550,7 +1550,7 @@ key_press_release(struct seat *seat, struct terminal *term, uint32_t serial,
     xassert(bindings != NULL);
 
     if (pressed) {
-        if (seat->unicode_mode.active) {
+        if (term->unicode_mode.active) {
             unicode_mode_input(seat, term, sym);
             return;
         }

render.c

@@ -1563,16 +1563,7 @@ static void
 render_overlay(struct terminal *term)
 {
     struct wayl_sub_surface *overlay = &term->window->overlay;
-    bool unicode_mode_active = false;
+    const bool unicode_mode_active = term->unicode_mode.active;
-
-    /* Check if unicode mode is active on at least one seat focusing
-     * this terminal instance */
-    tll_foreach(term->wl->seats, it) {
-        if (it->item.unicode_mode.active) {
-            unicode_mode_active = true;
-            break;
-        }
-    }
 
     const enum overlay_style style =
         term->is_searching ? OVERLAY_SEARCH :

search.c

@@ -1358,7 +1358,7 @@ execute_binding(struct seat *seat, struct terminal *term,
         return true;
 
     case BIND_ACTION_SEARCH_UNICODE_INPUT:
-        unicode_mode_activate(seat);
+        unicode_mode_activate(term);
         return true;
 
     case BIND_ACTION_SEARCH_COUNT:

terminal.h

@@ -719,6 +719,12 @@ struct terminal {
     bool ime_enabled;
 #endif
 
+    struct {
+        bool active;
+        int count;
+        char32_t character;
+    } unicode_mode;
+
     struct {
         bool in_progress;
         bool client_has_terminated;

unicode-mode.c

@@ -1,37 +1,36 @@
 #include "unicode-mode.h"
 
 #define LOG_MODULE "unicode-input"
-#define LOG_ENABLE_DBG 0
+#define LOG_ENABLE_DBG 1
 #include "log.h"
 #include "render.h"
 #include "search.h"
 
 void
-unicode_mode_activate(struct seat *seat)
+unicode_mode_activate(struct terminal *term)
 {
-    if (seat->unicode_mode.active)
+    if (term->unicode_mode.active)
         return;
 
-    seat->unicode_mode.active = true;
+    term->unicode_mode.active = true;
-    seat->unicode_mode.character = u'\0';
+    term->unicode_mode.character = u'\0';
-    seat->unicode_mode.count = 0;
+    term->unicode_mode.count = 0;
-    unicode_mode_updated(seat);
+    unicode_mode_updated(term);
 }
 
 void
-unicode_mode_deactivate(struct seat *seat)
+unicode_mode_deactivate(struct terminal *term)
 {
-    if (!seat->unicode_mode.active)
+    if (!term->unicode_mode.active)
         return;
 
-    seat->unicode_mode.active = false;
+    term->unicode_mode.active = false;
-    unicode_mode_updated(seat);
+    unicode_mode_updated(term);
 }
 
 void
-unicode_mode_updated(struct seat *seat)
+unicode_mode_updated(struct terminal *term)
 {
-    struct terminal *term = seat->kbd_focus;
     if (term == NULL)
         return;
 
@@ -52,10 +51,10 @@ unicode_mode_input(struct seat *seat, struct terminal *term,
     {
         char utf8[MB_CUR_MAX];
         size_t chars = c32rtomb(
-            utf8, seat->unicode_mode.character, &(mbstate_t){0});
+            utf8, term->unicode_mode.character, &(mbstate_t){0});
 
         LOG_DBG("Unicode input: 0x%06x -> %.*s",
-                seat->unicode_mode.character, (int)chars, utf8);
+                term->unicode_mode.character, (int)chars, utf8);
 
         if (chars != (size_t)-1) {
             if (term->is_searching)
@@ -64,7 +63,7 @@ unicode_mode_input(struct seat *seat, struct terminal *term,
                 term_to_slave(term, utf8, chars);
         }
 
-        unicode_mode_deactivate(seat);
+        unicode_mode_deactivate(term);
     }
 
     else if (sym == XKB_KEY_Escape ||
@@ -73,18 +72,18 @@ unicode_mode_input(struct seat *seat, struct terminal *term,
                                  sym == XKB_KEY_d ||
                                  sym == XKB_KEY_g)))
     {
-        unicode_mode_deactivate(seat);
+        unicode_mode_deactivate(term);
     }
 
     else if (sym == XKB_KEY_BackSpace) {
-        if (seat->unicode_mode.count > 0) {
+        if (term->unicode_mode.count > 0) {
-            seat->unicode_mode.character >>= 4;
+            term->unicode_mode.character >>= 4;
-            seat->unicode_mode.count--;
+            term->unicode_mode.count--;
-            unicode_mode_updated(seat);
+            unicode_mode_updated(term);
         }
     }
 
-    else if (seat->unicode_mode.count < 6) {
+    else if (term->unicode_mode.count < 6) {
         int digit = -1;
 
         /* 0-9, a-f, A-F */
@@ -99,10 +98,10 @@ unicode_mode_input(struct seat *seat, struct terminal *term,
 
         if (digit >= 0) {
             xassert(digit >= 0 && digit <= 0xf);
-            seat->unicode_mode.character <<= 4;
+            term->unicode_mode.character <<= 4;
-            seat->unicode_mode.character |= digit;
+            term->unicode_mode.character |= digit;
-            seat->unicode_mode.count++;
+            term->unicode_mode.count++;
-            unicode_mode_updated(seat);
+            unicode_mode_updated(term);
         }
     }
 }

unicode-mode.h

@@ -2,10 +2,10 @@
 
 #include <xkbcommon/xkbcommon-keysyms.h>
 
-#include "wayland.h"
+#include "terminal.h"
 
-void unicode_mode_activate(struct seat *seat);
+void unicode_mode_activate(struct terminal *term);
-void unicode_mode_deactivate(struct seat *seat);
+void unicode_mode_deactivate(struct terminal *term);
-void unicode_mode_updated(struct seat *seat);
+void unicode_mode_updated(struct terminal *term);
 void unicode_mode_input(struct seat *seat, struct terminal *term,
                         xkb_keysym_t sym);

wayland.h

@@ -243,12 +243,6 @@ struct seat {
         uint32_t serial;
     } ime;
 #endif
-
-    struct {
-        bool active;
-        int count;
-        char32_t character;
-    } unicode_mode;
 };
 
 enum csd_surface {