kc3-lang/libxkbcommon/src/state.c

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• Hash : c8a25645
  Author :
  Date : 2016-02-28T00:02:05
  

  state: factor out get_entry_for_mods() Will be useful later. Signed-off-by: Ran Benita <ran234@gmail.com>

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• src/state.c

• /************************************************************
   * Copyright (c) 1993 by Silicon Graphics Computer Systems, Inc.
   *
   * Permission to use, copy, modify, and distribute this
   * software and its documentation for any purpose and without
   * fee is hereby granted, 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 Silicon Graphics not be
   * used in advertising or publicity pertaining to distribution
   * of the software without specific prior written permission.
   * Silicon Graphics makes no representation about the suitability
   * of this software for any purpose. It is provided "as is"
   * without any express or implied warranty.
   *
   * SILICON GRAPHICS DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS
   * SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
   * AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL SILICON
   * GRAPHICS 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.
   *
   ********************************************************/
  
  /*
   * Copyright © 2012 Intel Corporation
   * Copyright © 2012 Ran Benita <ran234@gmail.com>
   *
   * Permission is hereby granted, free of charge, to any person obtaining a
   * copy of this software and associated documentation files (the "Software"),
   * to deal in the Software without restriction, including without limitation
   * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   * and/or sell copies of the Software, and to permit persons to whom the
   * Software is furnished to do so, subject to the following conditions:
   *
   * The above copyright notice and this permission notice (including the next
   * paragraph) shall be included in all copies or substantial portions of the
   * Software.
   *
   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
   * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
   * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
   * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
   * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
   * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
   * DEALINGS IN THE SOFTWARE.
   *
   * Author: Daniel Stone <daniel@fooishbar.org>
   */
  
  /*
   * This is a bastardised version of xkbActions.c from the X server which
   * does not support, for the moment:
   *   - AccessX sticky/debounce/etc (will come later)
   *   - pointer keys (may come later)
   *   - key redirects (unlikely)
   *   - messages (very unlikely)
   */
  
  #include "keymap.h"
  #include "keysym.h"
  #include "utf8.h"
  
  struct xkb_filter {
      union xkb_action action;
      const struct xkb_key *key;
      uint32_t priv;
      bool (*func)(struct xkb_state *state,
                   struct xkb_filter *filter,
                   const struct xkb_key *key,
                   enum xkb_key_direction direction);
      int refcnt;
  };
  
  struct state_components {
      /* These may be negative, because of -1 group actions. */
      int32_t base_group; /**< depressed */
      int32_t latched_group;
      int32_t locked_group;
      xkb_layout_index_t group; /**< effective */
  
      xkb_mod_mask_t base_mods; /**< depressed */
      xkb_mod_mask_t latched_mods;
      xkb_mod_mask_t locked_mods;
      xkb_mod_mask_t mods; /**< effective */
  
      xkb_led_mask_t leds;
  };
  
  struct xkb_state {
      /*
       * Before updating the state, we keep a copy of just this struct. This
       * allows us to report which components of the state have changed.
       */
      struct state_components components;
  
      /*
       * At each event, we accumulate all the needed modifications to the base
       * modifiers, and apply them at the end. These keep track of this state.
       */
      xkb_mod_mask_t set_mods;
      xkb_mod_mask_t clear_mods;
  
      /*
       * We mustn't clear a base modifier if there's another depressed key
       * which affects it, e.g. given this sequence
       * < Left Shift down, Right Shift down, Left Shift Up >
       * the modifier should still be set. This keeps the count.
       */
      int16_t mod_key_count[XKB_MAX_MODS];
  
      int refcnt;
      darray(struct xkb_filter) filters;
      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)
  {
      for (unsigned i = 0; i < type->num_entries; i++)
          if (entry_is_active(&type->entries[i]) &&
              type->entries[i].mods.mask == mods)
              return &type->entries[i];
      return NULL;
  }
  
  static const struct xkb_key_type_entry *
  get_entry_for_key_state(struct xkb_state *state, const struct xkb_key *key,
                          xkb_layout_index_t group)
  {
      const struct xkb_key_type *type = key->groups[group].type;
      xkb_mod_mask_t active_mods = state->components.mods & type->mods.mask;
      return get_entry_for_mods(type, active_mods);
  }
  
  /**
   * Returns the level to use for the given key and state, or
   * XKB_LEVEL_INVALID.
   */
  XKB_EXPORT xkb_level_index_t
  xkb_state_key_get_level(struct xkb_state *state, xkb_keycode_t kc,
                          xkb_layout_index_t layout)
  {
      const struct xkb_key *key = XkbKey(state->keymap, kc);
      const struct xkb_key_type_entry *entry;
  
      if (!key || layout >= key->num_groups)
          return XKB_LEVEL_INVALID;
  
      /* If we don't find an explicit match the default is 0. */
      entry = get_entry_for_key_state(state, key, layout);
      if (!entry)
          return 0;
  
      return entry->level;
  }
  
  xkb_layout_index_t
  XkbWrapGroupIntoRange(int32_t group,
                        xkb_layout_index_t num_groups,
                        enum xkb_range_exceed_type out_of_range_group_action,
                        xkb_layout_index_t out_of_range_group_number)
  {
      if (num_groups == 0)
          return XKB_LAYOUT_INVALID;
  
      if (group >= 0 && (xkb_layout_index_t) group < num_groups)
          return group;
  
      switch (out_of_range_group_action) {
      case RANGE_REDIRECT:
          if (out_of_range_group_number >= num_groups)
              return 0;
          return out_of_range_group_number;
  
      case RANGE_SATURATE:
          if (group < 0)
              return 0;
          else
              return num_groups - 1;
  
      case RANGE_WRAP:
      default:
          /*
           * C99 says a negative dividend in a modulo operation always
           * gives a negative result.
           */
          if (group < 0)
              return ((int) num_groups + (group % (int) num_groups));
          else
              return group % num_groups;
      }
  }
  
  /**
   * Returns the layout to use for the given key and state, taking
   * wrapping/clamping/etc into account, or XKB_LAYOUT_INVALID.
   */
  XKB_EXPORT xkb_layout_index_t
  xkb_state_key_get_layout(struct xkb_state *state, xkb_keycode_t kc)
  {
      const struct xkb_key *key = XkbKey(state->keymap, kc);
  
      if (!key)
          return XKB_LAYOUT_INVALID;
  
      return XkbWrapGroupIntoRange(state->components.group, key->num_groups,
                                   key->out_of_range_group_action,
                                   key->out_of_range_group_number);
  }
  
  static const union xkb_action *
  xkb_key_get_action(struct xkb_state *state, const struct xkb_key *key)
  {
      static const union xkb_action dummy = { .type = ACTION_TYPE_NONE };
  
      xkb_layout_index_t layout;
      xkb_level_index_t level;
  
      layout = xkb_state_key_get_layout(state, key->keycode);
      if (layout == XKB_LAYOUT_INVALID)
          return &dummy;
  
      level = xkb_state_key_get_level(state, key->keycode, layout);
      if (level == XKB_LEVEL_INVALID)
          return &dummy;
  
      return &key->groups[layout].levels[level].action;
  }
  
  static struct xkb_filter *
  xkb_filter_new(struct xkb_state *state)
  {
      struct xkb_filter *filter = NULL, *iter;
  
      darray_foreach(iter, state->filters) {
          if (iter->func)
              continue;
          filter = iter;
          break;
      }
  
      if (!filter) {
          darray_resize0(state->filters, darray_size(state->filters) + 1);
          filter = &darray_item(state->filters, darray_size(state->filters) -1);
      }
  
      filter->refcnt = 1;
      return filter;
  }
  
  /***====================================================================***/
  
  static bool
  xkb_filter_group_set_func(struct xkb_state *state,
                            struct xkb_filter *filter,
                            const struct xkb_key *key,
                            enum xkb_key_direction direction)
  {
      if (key != filter->key) {
          filter->action.group.flags &= ~ACTION_LOCK_CLEAR;
          return true;
      }
  
      if (direction == XKB_KEY_DOWN) {
          filter->refcnt++;
          return false;
      }
      else if (--filter->refcnt > 0) {
          return false;
      }
  
      state->components.base_group = filter->priv;
  
      if (filter->action.group.flags & ACTION_LOCK_CLEAR)
          state->components.locked_group = 0;
  
      filter->func = NULL;
      return true;
  }
  
  static void
  xkb_filter_group_set_new(struct xkb_state *state, struct xkb_filter *filter)
  {
      filter->priv = state->components.base_group;
      if (filter->action.group.flags & ACTION_ABSOLUTE_SWITCH)
          state->components.base_group = filter->action.group.group;
      else
          state->components.base_group += filter->action.group.group;
  }
  
  static bool
  xkb_filter_group_lock_func(struct xkb_state *state,
                             struct xkb_filter *filter,
                             const struct xkb_key *key,
                             enum xkb_key_direction direction)
  {
      if (key != filter->key)
          return true;
  
      if (direction == XKB_KEY_DOWN) {
          filter->refcnt++;
          return false;
      }
      if (--filter->refcnt > 0)
          return false;
  
      filter->func = NULL;
      return true;
  }
  
  static void
  xkb_filter_group_lock_new(struct xkb_state *state, struct xkb_filter *filter)
  {
      if (filter->action.group.flags & ACTION_ABSOLUTE_SWITCH)
          state->components.locked_group = filter->action.group.group;
      else
          state->components.locked_group += filter->action.group.group;
  }
  
  static bool
  xkb_filter_mod_set_func(struct xkb_state *state,
                          struct xkb_filter *filter,
                          const struct xkb_key *key,
                          enum xkb_key_direction direction)
  {
      if (key != filter->key) {
          filter->action.mods.flags &= ~ACTION_LOCK_CLEAR;
          return true;
      }
  
      if (direction == XKB_KEY_DOWN) {
          filter->refcnt++;
          return false;
      }
      else if (--filter->refcnt > 0) {
          return false;
      }
  
      state->clear_mods = filter->action.mods.mods.mask;
      if (filter->action.mods.flags & ACTION_LOCK_CLEAR)
          state->components.locked_mods &= ~filter->action.mods.mods.mask;
  
      filter->func = NULL;
      return true;
  }
  
  static void
  xkb_filter_mod_set_new(struct xkb_state *state, struct xkb_filter *filter)
  {
      state->set_mods = filter->action.mods.mods.mask;
  }
  
  static bool
  xkb_filter_mod_lock_func(struct xkb_state *state,
                           struct xkb_filter *filter,
                           const struct xkb_key *key,
                           enum xkb_key_direction direction)
  {
      if (key != filter->key)
          return true;
  
      if (direction == XKB_KEY_DOWN) {
          filter->refcnt++;
          return false;
      }
      if (--filter->refcnt > 0)
          return false;
  
      state->clear_mods |= filter->action.mods.mods.mask;
      if (!(filter->action.mods.flags & ACTION_LOCK_NO_UNLOCK))
          state->components.locked_mods &= ~filter->priv;
  
      filter->func = NULL;
      return true;
  }
  
  static void
  xkb_filter_mod_lock_new(struct xkb_state *state, struct xkb_filter *filter)
  {
      filter->priv = (state->components.locked_mods &
                      filter->action.mods.mods.mask);
      state->set_mods |= filter->action.mods.mods.mask;
      if (!(filter->action.mods.flags & ACTION_LOCK_NO_LOCK))
          state->components.locked_mods |= filter->action.mods.mods.mask;
  }
  
  enum xkb_key_latch_state {
      NO_LATCH,
      LATCH_KEY_DOWN,
      LATCH_PENDING,
  };
  
  static bool
  xkb_action_breaks_latch(const union xkb_action *action)
  {
      switch (action->type) {
      case ACTION_TYPE_NONE:
      case ACTION_TYPE_PTR_BUTTON:
      case ACTION_TYPE_PTR_LOCK:
      case ACTION_TYPE_CTRL_SET:
      case ACTION_TYPE_CTRL_LOCK:
      case ACTION_TYPE_SWITCH_VT:
      case ACTION_TYPE_TERMINATE:
          return true;
      default:
          return false;
      }
  }
  
  static bool
  xkb_filter_mod_latch_func(struct xkb_state *state,
                            struct xkb_filter *filter,
                            const struct xkb_key *key,
                            enum xkb_key_direction direction)
  {
      enum xkb_key_latch_state latch = filter->priv;
  
      if (direction == XKB_KEY_DOWN && latch == LATCH_PENDING) {
          /* If this is a new keypress and we're awaiting our single latched
           * keypress, then either break the latch if any random key is pressed,
           * or promote it to a lock or plain base set if it's the same
           * modifier. */
          const union xkb_action *action = xkb_key_get_action(state, key);
          if (action->type == ACTION_TYPE_MOD_LATCH &&
              action->mods.flags == filter->action.mods.flags &&
              action->mods.mods.mask == filter->action.mods.mods.mask) {
              filter->action = *action;
              if (filter->action.mods.flags & ACTION_LATCH_TO_LOCK) {
                  filter->action.type = ACTION_TYPE_MOD_LOCK;
                  filter->func = xkb_filter_mod_lock_func;
                  state->components.locked_mods |= filter->action.mods.mods.mask;
              }
              else {
                  filter->action.type = ACTION_TYPE_MOD_SET;
                  filter->func = xkb_filter_mod_set_func;
                  state->set_mods = filter->action.mods.mods.mask;
              }
              filter->key = key;
              state->components.latched_mods &= ~filter->action.mods.mods.mask;
              /* XXX beep beep! */
              return false;
          }
          else if (xkb_action_breaks_latch(action)) {
              /* XXX: This may be totally broken, we might need to break the
               *      latch in the next run after this press? */
              state->components.latched_mods &= ~filter->action.mods.mods.mask;
              filter->func = NULL;
              return true;
          }
      }
      else if (direction == XKB_KEY_UP && key == filter->key) {
          /* Our key got released.  If we've set it to clear locks, and we
           * currently have the same modifiers locked, then release them and
           * don't actually latch.  Else we've actually hit the latching
           * stage, so set PENDING and move our modifier from base to
           * latched. */
          if (latch == NO_LATCH ||
              ((filter->action.mods.flags & ACTION_LOCK_CLEAR) &&
               (state->components.locked_mods & filter->action.mods.mods.mask) ==
               filter->action.mods.mods.mask)) {
              /* XXX: We might be a bit overenthusiastic about clearing
               *      mods other filters have set here? */
              if (latch == LATCH_PENDING)
                  state->components.latched_mods &=
                      ~filter->action.mods.mods.mask;
              else
                  state->clear_mods = filter->action.mods.mods.mask;
              state->components.locked_mods &= ~filter->action.mods.mods.mask;
              filter->func = NULL;
          }
          else {
              latch = LATCH_PENDING;
              state->clear_mods = filter->action.mods.mods.mask;
              state->components.latched_mods |= filter->action.mods.mods.mask;
              /* XXX beep beep! */
          }
      }
      else if (direction == XKB_KEY_DOWN && latch == LATCH_KEY_DOWN) {
          /* Someone's pressed another key while we've still got the latching
           * key held down, so keep the base modifier state active (from
           * xkb_filter_mod_latch_new), but don't trip the latch, just clear
           * it as soon as the modifier gets released. */
          latch = NO_LATCH;
      }
  
      filter->priv = latch;
  
      return true;
  }
  
  static void
  xkb_filter_mod_latch_new(struct xkb_state *state, struct xkb_filter *filter)
  {
      filter->priv = LATCH_KEY_DOWN;
      state->set_mods = filter->action.mods.mods.mask;
  }
  
  static const struct {
      void (*new)(struct xkb_state *state, struct xkb_filter *filter);
      bool (*func)(struct xkb_state *state, struct xkb_filter *filter,
                   const struct xkb_key *key, enum xkb_key_direction direction);
  } filter_action_funcs[_ACTION_TYPE_NUM_ENTRIES] = {
      [ACTION_TYPE_MOD_SET]    = { xkb_filter_mod_set_new,
                                   xkb_filter_mod_set_func },
      [ACTION_TYPE_MOD_LATCH]  = { xkb_filter_mod_latch_new,
                                   xkb_filter_mod_latch_func },
      [ACTION_TYPE_MOD_LOCK]   = { xkb_filter_mod_lock_new,
                                   xkb_filter_mod_lock_func },
      [ACTION_TYPE_GROUP_SET]  = { xkb_filter_group_set_new,
                                   xkb_filter_group_set_func },
      [ACTION_TYPE_GROUP_LOCK] = { xkb_filter_group_lock_new,
                                   xkb_filter_group_lock_func },
  };
  
  /**
   * Applies any relevant filters to the key, first from the list of filters
   * that are currently active, then if no filter has claimed the key, possibly
   * apply a new filter from the key action.
   */
  static void
  xkb_filter_apply_all(struct xkb_state *state,
                       const struct xkb_key *key,
                       enum xkb_key_direction direction)
  {
      struct xkb_filter *filter;
      const union xkb_action *action;
      bool send = true;
  
      /* First run through all the currently active filters and see if any of
       * them have claimed this event. */
      darray_foreach(filter, state->filters) {
          if (!filter->func)
              continue;
          send = filter->func(state, filter, key, direction) && send;
      }
  
      if (!send || direction == XKB_KEY_UP)
          return;
  
      action = xkb_key_get_action(state, key);
  
      /*
       * It's possible for the keymap to set action->type explicitly, like so:
       *     interpret XF86_Next_VMode {
       *         action = Private(type=0x86, data="+VMode");
       *     };
       * We don't handle those.
       */
      if (action->type >= _ACTION_TYPE_NUM_ENTRIES)
          return;
  
      if (!filter_action_funcs[action->type].new)
          return;
  
      filter = xkb_filter_new(state);
      if (!filter)
          return; /* WSGO */
  
      filter->key = key;
      filter->func = filter_action_funcs[action->type].func;
      filter->action = *action;
      filter_action_funcs[action->type].new(state, filter);
  }
  
  XKB_EXPORT struct xkb_state *
  xkb_state_new(struct xkb_keymap *keymap)
  {
      struct xkb_state *ret;
  
      ret = calloc(sizeof(*ret), 1);
      if (!ret)
          return NULL;
  
      ret->refcnt = 1;
      ret->keymap = xkb_keymap_ref(keymap);
  
      return ret;
  }
  
  XKB_EXPORT struct xkb_state *
  xkb_state_ref(struct xkb_state *state)
  {
      state->refcnt++;
      return state;
  }
  
  XKB_EXPORT void
  xkb_state_unref(struct xkb_state *state)
  {
      if (!state || --state->refcnt > 0)
          return;
  
      xkb_keymap_unref(state->keymap);
      darray_free(state->filters);
      free(state);
  }
  
  XKB_EXPORT struct xkb_keymap *
  xkb_state_get_keymap(struct xkb_state *state)
  {
      return state->keymap;
  }
  
  /**
   * Update the LED state to match the rest of the xkb_state.
   */
  static void
  xkb_state_led_update_all(struct xkb_state *state)
  {
      xkb_led_index_t idx;
      const struct xkb_led *led;
  
      state->components.leds = 0;
  
      xkb_leds_enumerate(idx, led, state->keymap) {
          xkb_mod_mask_t mod_mask = 0;
          xkb_layout_mask_t group_mask = 0;
  
          if (led->which_mods != 0 && led->mods.mask != 0) {
              if (led->which_mods & XKB_STATE_MODS_EFFECTIVE)
                  mod_mask |= state->components.mods;
              if (led->which_mods & XKB_STATE_MODS_DEPRESSED)
                  mod_mask |= state->components.base_mods;
              if (led->which_mods & XKB_STATE_MODS_LATCHED)
                  mod_mask |= state->components.latched_mods;
              if (led->which_mods & XKB_STATE_MODS_LOCKED)
                  mod_mask |= state->components.locked_mods;
  
              if (led->mods.mask & mod_mask) {
                  state->components.leds |= (1u << idx);
                  continue;
              }
          }
  
          if (led->which_groups != 0 && led->groups != 0) {
              if (led->which_groups & XKB_STATE_LAYOUT_EFFECTIVE)
                  group_mask |= (1u << state->components.group);
              if (led->which_groups & XKB_STATE_LAYOUT_DEPRESSED)
                  group_mask |= (1u << state->components.base_group);
              if (led->which_groups & XKB_STATE_LAYOUT_LATCHED)
                  group_mask |= (1u << state->components.latched_group);
              if (led->which_groups & XKB_STATE_LAYOUT_LOCKED)
                  group_mask |= (1u << state->components.locked_group);
  
              if (led->groups & group_mask) {
                  state->components.leds |= (1u << idx);
                  continue;
              }
          }
  
          if (led->ctrls & state->keymap->enabled_ctrls) {
              state->components.leds |= (1u << idx);
              continue;
          }
      }
  }
  
  /**
   * Calculates the derived state (effective mods/group and LEDs) from an
   * up-to-date xkb_state.
   */
  static void
  xkb_state_update_derived(struct xkb_state *state)
  {
      xkb_layout_index_t wrapped;
  
      state->components.mods = (state->components.base_mods |
                                state->components.latched_mods |
                                state->components.locked_mods);
  
      /* TODO: Use groups_wrap control instead of always RANGE_WRAP. */
  
      wrapped = XkbWrapGroupIntoRange(state->components.locked_group,
                                      state->keymap->num_groups,
                                      RANGE_WRAP, 0);
      state->components.locked_group =
          (wrapped == XKB_LAYOUT_INVALID ? 0 : wrapped);
  
      wrapped = XkbWrapGroupIntoRange(state->components.base_group +
                                      state->components.latched_group +
                                      state->components.locked_group,
                                      state->keymap->num_groups,
                                      RANGE_WRAP, 0);
      state->components.group =
          (wrapped == XKB_LAYOUT_INVALID ? 0 : wrapped);
  
      xkb_state_led_update_all(state);
  }
  
  static enum xkb_state_component
  get_state_component_changes(const struct state_components *a,
                              const struct state_components *b)
  {
      xkb_mod_mask_t mask = 0;
  
      if (a->group != b->group)
          mask |= XKB_STATE_LAYOUT_EFFECTIVE;
      if (a->base_group != b->base_group)
          mask |= XKB_STATE_LAYOUT_DEPRESSED;
      if (a->latched_group != b->latched_group)
          mask |= XKB_STATE_LAYOUT_LATCHED;
      if (a->locked_group != b->locked_group)
          mask |= XKB_STATE_LAYOUT_LOCKED;
      if (a->mods != b->mods)
          mask |= XKB_STATE_MODS_EFFECTIVE;
      if (a->base_mods != b->base_mods)
          mask |= XKB_STATE_MODS_DEPRESSED;
      if (a->latched_mods != b->latched_mods)
          mask |= XKB_STATE_MODS_LATCHED;
      if (a->locked_mods != b->locked_mods)
          mask |= XKB_STATE_MODS_LOCKED;
      if (a->leds != b->leds)
          mask |= XKB_STATE_LEDS;
  
      return mask;
  }
  
  /**
   * Given a particular key event, updates the state structure to reflect the
   * new modifiers.
   */
  XKB_EXPORT enum xkb_state_component
  xkb_state_update_key(struct xkb_state *state, xkb_keycode_t kc,
                       enum xkb_key_direction direction)
  {
      xkb_mod_index_t i;
      xkb_mod_mask_t bit;
      struct state_components prev_components;
      const struct xkb_key *key = XkbKey(state->keymap, kc);
  
      if (!key)
          return 0;
  
      prev_components = state->components;
  
      state->set_mods = 0;
      state->clear_mods = 0;
  
      xkb_filter_apply_all(state, key, direction);
  
      for (i = 0, bit = 1; state->set_mods; i++, bit <<= 1) {
          if (state->set_mods & bit) {
              state->mod_key_count[i]++;
              state->components.base_mods |= bit;
              state->set_mods &= ~bit;
          }
      }
  
      for (i = 0, bit = 1; state->clear_mods; i++, bit <<= 1) {
          if (state->clear_mods & bit) {
              state->mod_key_count[i]--;
              if (state->mod_key_count[i] <= 0) {
                  state->components.base_mods &= ~bit;
                  state->mod_key_count[i] = 0;
              }
              state->clear_mods &= ~bit;
          }
      }
  
      xkb_state_update_derived(state);
  
      return get_state_component_changes(&prev_components, &state->components);
  }
  
  /**
   * Updates the state from a set of explicit masks as gained from
   * xkb_state_serialize_mods and xkb_state_serialize_groups.  As noted in the
   * documentation for these functions in xkbcommon.h, this round-trip is
   * lossy, and should only be used to update a slave state mirroring the
   * master, e.g. in a client/server window system.
   */
  XKB_EXPORT enum xkb_state_component
  xkb_state_update_mask(struct xkb_state *state,
                        xkb_mod_mask_t base_mods,
                        xkb_mod_mask_t latched_mods,
                        xkb_mod_mask_t locked_mods,
                        xkb_layout_index_t base_group,
                        xkb_layout_index_t latched_group,
                        xkb_layout_index_t locked_group)
  {
      struct state_components prev_components;
      xkb_mod_mask_t mask;
  
      prev_components = state->components;
  
      /* Only include modifiers which exist in the keymap. */
      mask = (xkb_mod_mask_t) ((1ull << xkb_keymap_num_mods(state->keymap)) - 1u);
  
      state->components.base_mods = base_mods & mask;
      state->components.latched_mods = latched_mods & mask;
      state->components.locked_mods = locked_mods & mask;
  
      /* Make sure the mods are fully resolved - since we get arbitrary
       * input, they might not be.
       *
       * It might seem more reasonable to do this only for components.mods
       * in xkb_state_update_derived(), rather than for each component
       * seperately.  That would allow to distinguish between "really"
       * depressed mods (would be in MODS_DEPRESSED) and indirectly
       * depressed to to a mapping (would only be in MODS_EFFECTIVE).
       * However, the traditional behavior of xkb_state_update_key() is that
       * if a vmod is depressed, its mappings are depressed with it; so we're
       * expected to do the same here.  Also, LEDs (usually) look if a real
       * mod is locked, not just effective; otherwise it won't be lit.
       *
       * We OR here because mod_mask_get_effective() drops vmods. */
      state->components.base_mods |=
          mod_mask_get_effective(state->keymap, state->components.base_mods);
      state->components.latched_mods |=
          mod_mask_get_effective(state->keymap, state->components.latched_mods);
      state->components.locked_mods |=
          mod_mask_get_effective(state->keymap, state->components.locked_mods);
  
      state->components.base_group = base_group;
      state->components.latched_group = latched_group;
      state->components.locked_group = locked_group;
  
      xkb_state_update_derived(state);
  
      return get_state_component_changes(&prev_components, &state->components);
  }
  
  /**
   * Provides the symbols to use for the given key and state.  Returns the
   * number of symbols pointed to in syms_out.
   */
  XKB_EXPORT int
  xkb_state_key_get_syms(struct xkb_state *state, xkb_keycode_t kc,
                         const xkb_keysym_t **syms_out)
  {
      xkb_layout_index_t layout;
      xkb_level_index_t level;
  
      layout = xkb_state_key_get_layout(state, kc);
      if (layout == XKB_LAYOUT_INVALID)
          goto err;
  
      level = xkb_state_key_get_level(state, kc, layout);
      if (level == XKB_LEVEL_INVALID)
          goto err;
  
      return xkb_keymap_key_get_syms_by_level(state->keymap, kc, layout, level,
                                              syms_out);
  
  err:
      *syms_out = NULL;
      return 0;
  }
  
  /*
   * http://www.x.org/releases/current/doc/kbproto/xkbproto.html#Interpreting_the_Lock_Modifier
   */
  static bool
  should_do_caps_transformation(struct xkb_state *state, xkb_keycode_t kc)
  {
      xkb_mod_index_t caps =
          xkb_keymap_mod_get_index(state->keymap, XKB_MOD_NAME_CAPS);
  
      return
          xkb_state_mod_index_is_active(state, caps, XKB_STATE_MODS_EFFECTIVE) > 0 &&
          xkb_state_mod_index_is_consumed(state, kc, caps) == 0;
  }
  
  /*
   * http://www.x.org/releases/current/doc/kbproto/xkbproto.html#Interpreting_the_Control_Modifier
   */
  static bool
  should_do_ctrl_transformation(struct xkb_state *state, xkb_keycode_t kc)
  {
      xkb_mod_index_t ctrl =
          xkb_keymap_mod_get_index(state->keymap, XKB_MOD_NAME_CTRL);
  
      return
          xkb_state_mod_index_is_active(state, ctrl, XKB_STATE_MODS_EFFECTIVE) > 0 &&
          xkb_state_mod_index_is_consumed(state, kc, ctrl) == 0;
  }
  
  /* Verbatim from libX11:src/xkb/XKBBind.c */
  static char
  XkbToControl(char ch)
  {
      char c = ch;
  
      if ((c >= '@' && c < '\177') || c == ' ')
          c &= 0x1F;
      else if (c == '2')
          c = '\000';
      else if (c >= '3' && c <= '7')
          c -= ('3' - '\033');
      else if (c == '8')
          c = '\177';
      else if (c == '/')
          c = '_' & 0x1F;
      return c;
  }
  
  /**
   * Provides either exactly one symbol, or XKB_KEY_NoSymbol.
   */
  XKB_EXPORT xkb_keysym_t
  xkb_state_key_get_one_sym(struct xkb_state *state, xkb_keycode_t kc)
  {
      const xkb_keysym_t *syms;
      xkb_keysym_t sym;
      int num_syms;
  
      num_syms = xkb_state_key_get_syms(state, kc, &syms);
      if (num_syms != 1)
          return XKB_KEY_NoSymbol;
  
      sym = syms[0];
  
      if (should_do_caps_transformation(state, kc))
          sym = xkb_keysym_to_upper(sym);
  
      return sym;
  }
  
  /*
   * The caps and ctrl transformations require some special handling,
   * so we cannot simply use xkb_state_get_one_sym() for them.
   * In particular, if Control is set, we must try very hard to find
   * some layout in which the keysym is ASCII and thus can be (maybe)
   * converted to a control character. libX11 allows to disable this
   * behavior with the XkbLC_ControlFallback (see XkbSetXlibControls(3)),
   * but it is enabled by default, yippee.
   */
  static xkb_keysym_t
  get_one_sym_for_string(struct xkb_state *state, xkb_keycode_t kc)
  {
      xkb_level_index_t level;
      xkb_layout_index_t layout, num_layouts;
      const xkb_keysym_t *syms;
      int nsyms;
      xkb_keysym_t sym;
  
      layout = xkb_state_key_get_layout(state, kc);
      num_layouts = xkb_keymap_num_layouts_for_key(state->keymap, kc);
      level = xkb_state_key_get_level(state, kc, layout);
      if (layout == XKB_LAYOUT_INVALID || num_layouts == 0 ||
          level == XKB_LEVEL_INVALID)
          return XKB_KEY_NoSymbol;
  
      nsyms = xkb_keymap_key_get_syms_by_level(state->keymap, kc,
                                               layout, level, &syms);
      if (nsyms != 1)
          return XKB_KEY_NoSymbol;
      sym = syms[0];
  
      if (should_do_ctrl_transformation(state, kc) && sym > 127u) {
          for (xkb_layout_index_t i = 0; i < num_layouts; i++) {
              level = xkb_state_key_get_level(state, kc, i);
              if (level == XKB_LEVEL_INVALID)
                  continue;
  
              nsyms = xkb_keymap_key_get_syms_by_level(state->keymap, kc,
                                                       i, level, &syms);
              if (nsyms == 1 && syms[0] <= 127u) {
                  sym = syms[0];
                  break;
              }
          }
      }
  
      if (should_do_caps_transformation(state, kc)) {
          sym = xkb_keysym_to_upper(sym);
      }
  
      return sym;
  }
  
  XKB_EXPORT int
  xkb_state_key_get_utf8(struct xkb_state *state, xkb_keycode_t kc,
                         char *buffer, size_t size)
  {
      xkb_keysym_t sym;
      const xkb_keysym_t *syms;
      int nsyms;
      int offset;
      char tmp[7];
  
      sym = get_one_sym_for_string(state, kc);
      if (sym != XKB_KEY_NoSymbol) {
          nsyms = 1; syms = &sym;
      }
      else {
          nsyms = xkb_state_key_get_syms(state, kc, &syms);
      }
  
      /* Make sure not to truncate in the middle of a UTF-8 sequence. */
      offset = 0;
      for (int i = 0; i < nsyms; i++) {
          int ret = xkb_keysym_to_utf8(syms[i], tmp, sizeof(tmp));
          if (ret <= 0)
              goto err_bad;
  
          ret--;
          if ((size_t) (offset + ret) <= size)
              memcpy(buffer + offset, tmp, ret);
          offset += ret;
      }
  
      if ((size_t) offset >= size)
          goto err_trunc;
      buffer[offset] = '\0';
  
      if (!is_valid_utf8(buffer, offset))
          goto err_bad;
  
      if (offset == 1 && (unsigned int) buffer[0] <= 127u &&
          should_do_ctrl_transformation(state, kc))
          buffer[0] = XkbToControl(buffer[0]);
  
      return offset;
  
  err_trunc:
      if (size > 0)
          buffer[size - 1] = '\0';
      return offset;
  
  err_bad:
      if (size > 0)
          buffer[0] = '\0';
      return 0;
  }
  
  XKB_EXPORT uint32_t
  xkb_state_key_get_utf32(struct xkb_state *state, xkb_keycode_t kc)
  {
      xkb_keysym_t sym;
      uint32_t cp;
  
      sym = get_one_sym_for_string(state, kc);
      cp = xkb_keysym_to_utf32(sym);
  
      if (cp <= 127u && should_do_ctrl_transformation(state, kc))
          cp = (uint32_t) XkbToControl((char) cp);
  
      return cp;
  }
  
  /**
   * Serialises the requested modifier state into an xkb_mod_mask_t, with all
   * the same disclaimers as in xkb_state_update_mask.
   */
  XKB_EXPORT xkb_mod_mask_t
  xkb_state_serialize_mods(struct xkb_state *state,
                           enum xkb_state_component type)
  {
      xkb_mod_mask_t ret = 0;
  
      if (type & XKB_STATE_MODS_EFFECTIVE)
          return state->components.mods;
  
      if (type & XKB_STATE_MODS_DEPRESSED)
          ret |= state->components.base_mods;
      if (type & XKB_STATE_MODS_LATCHED)
          ret |= state->components.latched_mods;
      if (type & XKB_STATE_MODS_LOCKED)
          ret |= state->components.locked_mods;
  
      return ret;
  }
  
  /**
   * Serialises the requested group state, with all the same disclaimers as
   * in xkb_state_update_mask.
   */
  XKB_EXPORT xkb_layout_index_t
  xkb_state_serialize_layout(struct xkb_state *state,
                             enum xkb_state_component type)
  {
      xkb_layout_index_t ret = 0;
  
      if (type & XKB_STATE_LAYOUT_EFFECTIVE)
          return state->components.group;
  
      if (type & XKB_STATE_LAYOUT_DEPRESSED)
          ret += state->components.base_group;
      if (type & XKB_STATE_LAYOUT_LATCHED)
          ret += state->components.latched_group;
      if (type & XKB_STATE_LAYOUT_LOCKED)
          ret += state->components.locked_group;
  
      return ret;
  }
  
  /**
   * Gets a modifier mask and returns the resolved effective mask; this
   * is needed because some modifiers can also map to other modifiers, e.g.
   * the "NumLock" modifier usually also sets the "Mod2" modifier.
   */
  xkb_mod_mask_t
  mod_mask_get_effective(struct xkb_keymap *keymap, xkb_mod_mask_t mods)
  {
      const struct xkb_mod *mod;
      xkb_mod_index_t i;
      xkb_mod_mask_t mask;
  
      /* The effective mask is only real mods for now. */
      mask = mods & MOD_REAL_MASK_ALL;
  
      xkb_mods_enumerate(i, mod, &keymap->mods)
          if (mods & (1u << i))
              mask |= mod->mapping;
  
      return mask;
  }
  
  /**
   * Returns 1 if the given modifier is active with the specified type(s), 0 if
   * not, or -1 if the modifier is invalid.
   */
  XKB_EXPORT int
  xkb_state_mod_index_is_active(struct xkb_state *state,
                                xkb_mod_index_t idx,
                                enum xkb_state_component type)
  {
      if (idx >= xkb_keymap_num_mods(state->keymap))
          return -1;
  
      return !!(xkb_state_serialize_mods(state, type) & (1u << idx));
  }
  
  /**
   * Helper function for xkb_state_mod_indices_are_active and
   * xkb_state_mod_names_are_active.
   */
  static int
  match_mod_masks(struct xkb_state *state,
                  enum xkb_state_component type,
                  enum xkb_state_match match,
                  xkb_mod_mask_t wanted)
  {
      xkb_mod_mask_t active = xkb_state_serialize_mods(state, type);
  
      if (!(match & XKB_STATE_MATCH_NON_EXCLUSIVE) && (active & ~wanted))
          return 0;
  
      if (match & XKB_STATE_MATCH_ANY)
          return !!(active & wanted);
      else
          return (active & wanted) == wanted;
  
      return 0;
  }
  
  /**
   * Returns 1 if the modifiers are active with the specified type(s), 0 if
   * not, or -1 if any of the modifiers are invalid.
   */
  XKB_EXPORT int
  xkb_state_mod_indices_are_active(struct xkb_state *state,
                                   enum xkb_state_component type,
                                   enum xkb_state_match match,
                                   ...)
  {
      va_list ap;
      xkb_mod_mask_t wanted = 0;
      int ret = 0;
      xkb_mod_index_t num_mods = xkb_keymap_num_mods(state->keymap);
  
      va_start(ap, match);
      while (1) {
          xkb_mod_index_t idx = va_arg(ap, xkb_mod_index_t);
          if (idx == XKB_MOD_INVALID)
              break;
          if (idx >= num_mods) {
              ret = -1;
              break;
          }
          wanted |= (1u << idx);
      }
      va_end(ap);
  
      if (ret == -1)
          return ret;
  
      return match_mod_masks(state, type, match, wanted);
  }
  
  /**
   * Returns 1 if the given modifier is active with the specified type(s), 0 if
   * not, or -1 if the modifier is invalid.
   */
  XKB_EXPORT int
  xkb_state_mod_name_is_active(struct xkb_state *state, const char *name,
                               enum xkb_state_component type)
  {
      xkb_mod_index_t idx = xkb_keymap_mod_get_index(state->keymap, name);
  
      if (idx == XKB_MOD_INVALID)
          return -1;
  
      return xkb_state_mod_index_is_active(state, idx, type);
  }
  
  /**
   * Returns 1 if the modifiers are active with the specified type(s), 0 if
   * not, or -1 if any of the modifiers are invalid.
   */
  XKB_EXPORT ATTR_NULL_SENTINEL int
  xkb_state_mod_names_are_active(struct xkb_state *state,
                                 enum xkb_state_component type,
                                 enum xkb_state_match match,
                                 ...)
  {
      va_list ap;
      xkb_mod_mask_t wanted = 0;
      int ret = 0;
  
      va_start(ap, match);
      while (1) {
          xkb_mod_index_t idx;
          const char *str = va_arg(ap, const char *);
          if (str == NULL)
              break;
          idx = xkb_keymap_mod_get_index(state->keymap, str);
          if (idx == XKB_MOD_INVALID) {
              ret = -1;
              break;
          }
          wanted |= (1u << idx);
      }
      va_end(ap);
  
      if (ret == -1)
          return ret;
  
      return match_mod_masks(state, type, match, wanted);
  }
  
  /**
   * Returns 1 if the given group is active with the specified type(s), 0 if
   * not, or -1 if the group is invalid.
   */
  XKB_EXPORT int
  xkb_state_layout_index_is_active(struct xkb_state *state,
                                  xkb_layout_index_t idx,
                                  enum xkb_state_component type)
  {
      int ret = 0;
  
      if (idx >= state->keymap->num_groups)
          return -1;
  
      if (type & XKB_STATE_LAYOUT_EFFECTIVE)
          ret |= (state->components.group == idx);
      if (type & XKB_STATE_LAYOUT_DEPRESSED)
          ret |= (state->components.base_group == (int32_t) idx);
      if (type & XKB_STATE_LAYOUT_LATCHED)
          ret |= (state->components.latched_group == (int32_t) idx);
      if (type & XKB_STATE_LAYOUT_LOCKED)
          ret |= (state->components.locked_group == (int32_t) idx);
  
      return ret;
  }
  
  /**
   * Returns 1 if the given modifier is active with the specified type(s), 0 if
   * not, or -1 if the modifier is invalid.
   */
  XKB_EXPORT int
  xkb_state_layout_name_is_active(struct xkb_state *state, const char *name,
                                  enum xkb_state_component type)
  {
      xkb_layout_index_t idx = xkb_keymap_layout_get_index(state->keymap, name);
  
      if (idx == XKB_LAYOUT_INVALID)
          return -1;
  
      return xkb_state_layout_index_is_active(state, idx, type);
  }
  
  /**
   * Returns 1 if the given LED is active, 0 if not, or -1 if the LED is invalid.
   */
  XKB_EXPORT int
  xkb_state_led_index_is_active(struct xkb_state *state, xkb_led_index_t idx)
  {
      if (idx >= state->keymap->num_leds ||
          state->keymap->leds[idx].name == XKB_ATOM_NONE)
          return -1;
  
      return !!(state->components.leds & (1u << idx));
  }
  
  /**
   * Returns 1 if the given LED is active, 0 if not, or -1 if the LED is invalid.
   */
  XKB_EXPORT int
  xkb_state_led_name_is_active(struct xkb_state *state, const char *name)
  {
      xkb_led_index_t idx = xkb_keymap_led_get_index(state->keymap, name);
  
      if (idx == XKB_LED_INVALID)
          return -1;
  
      return xkb_state_led_index_is_active(state, idx);
  }
  
  static xkb_mod_mask_t
  key_get_consumed(struct xkb_state *state, const struct xkb_key *key)
  {
      const struct xkb_key_type *type;
      const struct xkb_key_type_entry *entry;
      xkb_mod_mask_t preserve;
      xkb_layout_index_t group;
  
      group = xkb_state_key_get_layout(state, key->keycode);
      if (group == XKB_LAYOUT_INVALID)
          return 0;
  
      type = key->groups[group].type;
  
      entry = get_entry_for_key_state(state, key, group);
      if (entry)
          preserve = entry->preserve.mask;
      else
          preserve = 0;
  
      return type->mods.mask & ~preserve;
  }
  
  /**
   * Tests to see if a modifier is used up by our translation of a
   * keycode to keysyms, taking note of the current modifier state and
   * the appropriate key type's preserve information, if any. This allows
   * the user to mask out the modifier in later processing of the
   * modifiers, e.g. when implementing hot keys or accelerators.
   *
   * See also, for example:
   * - XkbTranslateKeyCode(3), mod_rtrn return value, from libX11.
   * - gdk_keymap_translate_keyboard_state, consumed_modifiers return value,
   *   from gtk+.
   */
  XKB_EXPORT int
  xkb_state_mod_index_is_consumed(struct xkb_state *state, xkb_keycode_t kc,
                                  xkb_mod_index_t idx)
  {
      const struct xkb_key *key = XkbKey(state->keymap, kc);
  
      if (!key || idx >= xkb_keymap_num_mods(state->keymap))
          return -1;
  
      return !!((1u << idx) & key_get_consumed(state, key));
  }
  
  /**
   * Calculates which modifiers should be consumed during key processing,
   * and returns the mask with all these modifiers removed.  e.g. if
   * given a state of Alt and Shift active for a two-level alphabetic
   * key containing plus and equal on the first and second level
   * respectively, will return a mask of only Alt, as Shift has been
   * consumed by the type handling.
   */
  XKB_EXPORT xkb_mod_mask_t
  xkb_state_mod_mask_remove_consumed(struct xkb_state *state, xkb_keycode_t kc,
                                     xkb_mod_mask_t mask)
  {
      const struct xkb_key *key = XkbKey(state->keymap, kc);
  
      if (!key)
          return 0;
  
      return mask & ~key_get_consumed(state, key);
  }
  
  XKB_EXPORT xkb_mod_mask_t
  xkb_state_key_get_consumed_mods(struct xkb_state *state, xkb_keycode_t kc)
  {
      const struct xkb_key *key = XkbKey(state->keymap, kc);
  
      if (!key)
          return 0;
  
      return key_get_consumed(state, key);
  }
  

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