btif/src/btif_sm.cc

/******************************************************************************
 *
 *  Copyright (C) 2009-2012 Broadcom Corporation
 *
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at:
 *
 *  http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 *
 ******************************************************************************/

/*****************************************************************************
 *
 *  Filename:      btif_sm.c
 *
 *  Description:   Generic BTIF state machine API
 *
 *****************************************************************************/

#define LOG_TAG "bt_btif"

#include "btif_sm.h"

#include "bt_common.h"
#include "btif_common.h"
#include "osi/include/allocator.h"

/*****************************************************************************
 *  Local type definitions
 *****************************************************************************/
typedef struct {
  btif_sm_state_t state;
  btif_sm_handler_t* p_handlers;
} btif_sm_cb_t;

/*****************************************************************************
 *  Functions
 *****************************************************************************/

/*****************************************************************************
 *
 * Function     btif_sm_init
 *
 * Description  Initializes the state machine with the state handlers
 *              The caller should ensure that the table and the corresponding
 *              states match. The location that 'p_handlers' points to shall
 *              be available until the btif_sm_shutdown API is invoked.
 *
 * Returns      Returns a pointer to the initialized state machine handle.
 *
 *****************************************************************************/

btif_sm_handle_t btif_sm_init(const btif_sm_handler_t* p_handlers,
                              btif_sm_state_t initial_state) {
  if (p_handlers == NULL) {
    BTIF_TRACE_ERROR("%s : p_handlers is NULL", __func__);
    return NULL;
  }

  btif_sm_cb_t* p_cb = (btif_sm_cb_t*)osi_malloc(sizeof(btif_sm_cb_t));
  p_cb->state = initial_state;
  p_cb->p_handlers = (btif_sm_handler_t*)p_handlers;

  /* Send BTIF_SM_ENTER_EVT to the initial state */
  p_cb->p_handlers[initial_state](BTIF_SM_ENTER_EVT, NULL);

  return (btif_sm_handle_t)p_cb;
}

/*****************************************************************************
 *
 * Function     btif_sm_shutdown
 *
 * Description  Tears down the state machine
 *
 * Returns      None
 *
 *****************************************************************************/
void btif_sm_shutdown(btif_sm_handle_t handle) {
  btif_sm_cb_t* p_cb = (btif_sm_cb_t*)handle;

  if (p_cb == NULL) {
    BTIF_TRACE_ERROR("%s : Invalid handle", __func__);
    return;
  }
  osi_free(p_cb);
}

/*****************************************************************************
 *
 * Function     btif_sm_get_state
 *
 * Description  Fetches the current state of the state machine
 *
 * Returns      Current state
 *
 *****************************************************************************/
btif_sm_state_t btif_sm_get_state(btif_sm_handle_t handle) {
  btif_sm_cb_t* p_cb = (btif_sm_cb_t*)handle;

  if (p_cb == NULL) {
    BTIF_TRACE_ERROR("%s : Invalid handle", __func__);
    return 0;
  }

  return p_cb->state;
}

/*****************************************************************************
 *
 * Function     btif_sm_dispatch
 *
 * Description  Dispatches the 'event' along with 'data' to the current state
 *              handler
 *
 * Returns      BT_STATUS_SUCCESS on success
 *              BT_STATUS_UNHANDLED if event was not processed
 *              BT_STATUS_FAIL otherwise
 *
 *****************************************************************************/
bt_status_t btif_sm_dispatch(btif_sm_handle_t handle, btif_sm_event_t event,
                             void* data) {
  bt_status_t status = BT_STATUS_SUCCESS;

  btif_sm_cb_t* p_cb = (btif_sm_cb_t*)handle;

  if (p_cb == NULL) {
    BTIF_TRACE_ERROR("%s : Invalid handle", __func__);
    return BT_STATUS_FAIL;
  }

  if (p_cb->p_handlers[p_cb->state](event, data) == false)
    return BT_STATUS_UNHANDLED;

  return status;
}

/*****************************************************************************
 *
 * Function     btif_sm_change_state
 *
 * Description  Make a transition to the new 'state'. The 'BTIF_SM_EXIT_EVT'
 *              shall be invoked before exiting the current state. The
 *              'BTIF_SM_ENTER_EVT' shall be invoked before entering the new
 *              state
 *
 * Returns      BT_STATUS_SUCCESS on success
 *              BT_STATUS_UNHANDLED if event was not processed
 *              BT_STATUS_FAIL otherwise
 *
 *****************************************************************************/
bt_status_t btif_sm_change_state(btif_sm_handle_t handle,
                                 btif_sm_state_t state) {
  bt_status_t status = BT_STATUS_SUCCESS;
  btif_sm_cb_t* p_cb = (btif_sm_cb_t*)handle;

  if (p_cb == NULL) {
    BTIF_TRACE_ERROR("%s : Invalid handle", __func__);
    return BT_STATUS_FAIL;
  }

  /* Send exit event to the current state */
  if (p_cb->p_handlers[p_cb->state](BTIF_SM_EXIT_EVT, NULL) == false)
    status = BT_STATUS_UNHANDLED;

  /* Change to the new state */
  p_cb->state = state;

  /* Send enter event to the new state */
  if (p_cb->p_handlers[p_cb->state](BTIF_SM_ENTER_EVT, NULL) == false)
    status = BT_STATUS_UNHANDLED;

  return status;
}