Properly reset state when enabling text input

When starting text input, not all state was reset properly. The text
input protocol requires to be re-enabled every time text input changes,
which SDL did not do. Also, XKB compose state was not reset at all,
causing composite and dead keys to carry over from when text input was
disabled.

Author: Hanicef

src/video/wayland/SDL_waylandevents.c

@@ -1173,6 +1173,9 @@ static void keyboard_handle_enter(void *data, struct wl_keyboard *keyboard,
         SDL_IME_SetFocus(SDL_TRUE);
     }
 #endif
+    if (input->text_input && input->text_input->is_enabled) {
+        Wayland_EnableTextInput(input->text_input);
+    }
 
     wl_array_for_each (key, keys) {
         const SDL_Scancode scancode = Wayland_get_scancode_from_key(input, *key + 8);
@@ -1234,7 +1237,7 @@ static SDL_bool keyboard_input_get_text(char text[8], const struct SDL_WaylandIn
     const xkb_keysym_t *syms;
     xkb_keysym_t sym;
 
-    if (!window || window->keyboard_device != input || !input->xkb.state || !input->text_input->is_enabled) {
+    if (!window || window->keyboard_device != input || !input->xkb.state) {
         return SDL_FALSE;
     }
 

src/video/wayland/SDL_waylandkeyboard.c

@@ -51,42 +51,51 @@ void Wayland_QuitKeyboard(_THIS)
 #endif
 }
 
+void Wayland_EnableTextInput(SDL_WaylandTextInput *text_input)
+{
+    const SDL_Rect *rect = &text_input->cursor_rect;
+
+    /* For some reason this has to be done twice, it appears to be a
+     * bug in mutter? Maybe?
+     * -flibit
+     */
+    zwp_text_input_v3_enable(text_input->text_input);
+    zwp_text_input_v3_commit(text_input->text_input);
+    zwp_text_input_v3_enable(text_input->text_input);
+    zwp_text_input_v3_commit(text_input->text_input);
+
+    /* Now that it's enabled, set the input properties */
+    zwp_text_input_v3_set_content_type(text_input->text_input,
+                                       ZWP_TEXT_INPUT_V3_CONTENT_HINT_NONE,
+                                       ZWP_TEXT_INPUT_V3_CONTENT_PURPOSE_NORMAL);
+    if (!SDL_RectEmpty(rect)) {
+        /* This gets reset on enable so we have to cache it */
+        zwp_text_input_v3_set_cursor_rectangle(text_input->text_input,
+                                               rect->x,
+                                               rect->y,
+                                               rect->w,
+                                               rect->h);
+    }
+    zwp_text_input_v3_commit(text_input->text_input);
+}
+
 void Wayland_StartTextInput(_THIS)
 {
     SDL_VideoData *driverdata = _this->driverdata;
 
     if (driverdata->text_input_manager) {
         struct SDL_WaylandInput *input = driverdata->input;
         if (input && input->text_input) {
-            const SDL_Rect *rect = &input->text_input->cursor_rect;
-
             /* Don't re-enable if we're already enabled. */
             if (input->text_input->is_enabled) {
                 return;
             }
 
-            /* For some reason this has to be done twice, it appears to be a
-             * bug in mutter? Maybe?
-             * -flibit
-             */
-            zwp_text_input_v3_enable(input->text_input->text_input);
-            zwp_text_input_v3_commit(input->text_input->text_input);
-            zwp_text_input_v3_enable(input->text_input->text_input);
-            zwp_text_input_v3_commit(input->text_input->text_input);
-
-            /* Now that it's enabled, set the input properties */
-            zwp_text_input_v3_set_content_type(input->text_input->text_input,
-                                               ZWP_TEXT_INPUT_V3_CONTENT_HINT_NONE,
-                                               ZWP_TEXT_INPUT_V3_CONTENT_PURPOSE_NORMAL);
-            if (!SDL_RectEmpty(rect)) {
-                /* This gets reset on enable so we have to cache it */
-                zwp_text_input_v3_set_cursor_rectangle(input->text_input->text_input,
-                                                       rect->x,
-                                                       rect->y,
-                                                       rect->w,
-                                                       rect->h);
+            Wayland_EnableTextInput(input->text_input);
+            if (input->xkb.compose_state) {
+                /* Reset compose state so composite and dead keys don't carry over */
+                WAYLAND_xkb_compose_state_reset(input->xkb.compose_state);
             }
-            zwp_text_input_v3_commit(input->text_input->text_input);
             input->text_input->is_enabled = SDL_TRUE;
         }
     }

src/video/wayland/SDL_waylandkeyboard.h

@@ -33,6 +33,7 @@ typedef struct SDL_WaylandTextInput
 
 extern int Wayland_InitKeyboard(_THIS);
 extern void Wayland_QuitKeyboard(_THIS);
+extern void Wayland_EnableTextInput(SDL_WaylandTextInput *input);
 extern void Wayland_StartTextInput(_THIS);
 extern void Wayland_StopTextInput(_THIS);
 extern void Wayland_SetTextInputRect(_THIS, const SDL_Rect *rect);

src/video/wayland/SDL_waylandsym.h

@@ -146,6 +146,7 @@ SDL_WAYLAND_SYM(struct xkb_compose_table *, xkb_compose_table_new_from_locale, (
                       const char *locale, enum xkb_compose_compile_flags) )
 SDL_WAYLAND_SYM(void, xkb_compose_table_unref, (struct xkb_compose_table *) )
 SDL_WAYLAND_SYM(struct xkb_compose_state *, xkb_compose_state_new, (struct xkb_compose_table *, enum xkb_compose_state_flags) )
+SDL_WAYLAND_SYM(void, xkb_compose_state_reset, (struct xkb_compose_state *) )
 SDL_WAYLAND_SYM(void, xkb_compose_state_unref, (struct xkb_compose_state *) )
 SDL_WAYLAND_SYM(enum xkb_compose_feed_result, xkb_compose_state_feed, (struct xkb_compose_state *, xkb_keysym_t) )
 SDL_WAYLAND_SYM(enum xkb_compose_status, xkb_compose_state_get_status, (struct xkb_compose_state *) )