API to query modifier set required to type a keysym

The new API is useful to implement features like auto-type and
desktop automation. Since the inputs for these features is usually
specified in terms of the symbols that need to be typed, the
implementation needs to be able to invert the keycode->keysym
transformation and produce a sequence of keycodes that can be used
to type the requested character(s).

3 files changed, 44 insertions, 11 deletions

diff --git a/src/keymap.c b/src/keymap.c
index 8e6cb67..54ac7c0 100644
--- a/src/keymap.c
+++ b/src/keymap.c
@@ -409,6 +409,39 @@ xkb_keymap_led_get_index(struct xkb_keymap *keymap, const char *name)
     return XKB_LED_INVALID;
 }
 
+XKB_EXPORT size_t
+xkb_keymap_key_get_mods_for_level(struct xkb_keymap *keymap,
+                                  xkb_keycode_t kc,
+                                  xkb_layout_index_t layout,
+                                  xkb_level_index_t level,
+                                  xkb_mod_mask_t *masks_out,
+                                  size_t masks_size)
+{
+    const struct xkb_key *key = XkbKey(keymap, kc);
+    if (!key)
+        return 0;
+
+    layout = XkbWrapGroupIntoRange(layout, key->num_groups,
+                                   key->out_of_range_group_action,
+                                   key->out_of_range_group_number);
+    if (layout == XKB_LAYOUT_INVALID)
+        return 0;
+
+    if (level >= XkbKeyNumLevels(key, layout))
+        return 0;
+
+    const struct xkb_key_type *type = key->groups[layout].type;
+
+    size_t count = 0;
+    for (unsigned i = 0; i < type->num_entries && count < masks_size; i++)
+        if (entry_is_active(&type->entries[i]) &&
+            type->entries[i].level == level) {
+            masks_out[count] = type->entries[i].mods.mask;
+            ++count;
+        }
+    return count;
+}
+
 /**
  * As below, but takes an explicit layout/level rather than state.
  */
diff --git a/src/keymap.h b/src/keymap.h
index c15052b..7c5341d 100644
--- a/src/keymap.h
+++ b/src/keymap.h
@@ -438,6 +438,17 @@ XkbKeyNumLevels(const struct xkb_key *key, xkb_layout_index_t layout)
     return key->groups[layout].type->num_levels;
 }
 
+/*
+ * If the virtual modifiers are not bound to anything, the entry
+ * is not active and should be skipped. xserver does this with
+ * cached entry->active field.
+ */
+static inline bool
+entry_is_active(const struct xkb_key_type_entry *entry)
+{
+    return entry->mods.mods == 0 || entry->mods.mask != 0;
+}
+
 struct xkb_keymap *
 xkb_keymap_new(struct xkb_context *ctx,
                enum xkb_keymap_format format,
diff --git a/src/state.c b/src/state.c
index 2d07be4..b269e6d 100644
--- a/src/state.c
+++ b/src/state.c
@@ -118,17 +118,6 @@ struct xkb_state {
     struct xkb_keymap *keymap;
 };
 
-/*
- * If the virtual modifiers are not bound to anything, the entry
- * is not active and should be skipped. xserver does this with
- * cached entry->active field.
- */
-static bool
-entry_is_active(const struct xkb_key_type_entry *entry)
-{
-    return entry->mods.mods == 0 || entry->mods.mask != 0;
-}
-
 static const struct xkb_key_type_entry *
 get_entry_for_mods(const struct xkb_key_type *type, xkb_mod_mask_t mods)
 {