btif/src/btif_profile_queue.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_profile_queue.c
 *
 *  Description:   Bluetooth remote device connection queuing implementation.
 *
 ******************************************************************************/

#define LOG_TAG "bt_btif_queue"

#include "btif_profile_queue.h"

#include <assert.h>
#include <string.h>

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

/*******************************************************************************
 *  Local type definitions
 ******************************************************************************/

typedef enum {
  BTIF_QUEUE_CONNECT_EVT,
  BTIF_QUEUE_ADVANCE_EVT,
} btif_queue_event_t;

typedef struct {
  bt_bdaddr_t bda;
  uint16_t uuid;
  bool busy;
  btif_connect_cb_t connect_cb;
} connect_node_t;

/*******************************************************************************
 *  Static variables
 ******************************************************************************/

static list_t* connect_queue;

static const size_t MAX_REASONABLE_REQUESTS = 10;

/*******************************************************************************
 *  Queue helper functions
 ******************************************************************************/

static void queue_int_add(connect_node_t* p_param) {
  if (!connect_queue) {
    connect_queue = list_new(osi_free);
    assert(connect_queue != NULL);
  }

  // Sanity check to make sure we're not leaking connection requests
  assert(list_length(connect_queue) < MAX_REASONABLE_REQUESTS);

  for (const list_node_t* node = list_begin(connect_queue);
       node != list_end(connect_queue); node = list_next(node)) {
    if (((connect_node_t*)list_node(node))->uuid == p_param->uuid) {
      LOG_INFO(LOG_TAG, "%s dropping duplicate connect request for uuid: %04x",
               __func__, p_param->uuid);
      return;
    }
  }

  connect_node_t* p_node = (connect_node_t*)osi_malloc(sizeof(connect_node_t));
  memcpy(p_node, p_param, sizeof(connect_node_t));
  list_append(connect_queue, p_node);
}

static void queue_int_advance() {
  if (connect_queue && !list_is_empty(connect_queue))
    list_remove(connect_queue, list_front(connect_queue));
}

static void queue_int_handle_evt(uint16_t event, char* p_param) {
  switch (event) {
    case BTIF_QUEUE_CONNECT_EVT:
      queue_int_add((connect_node_t*)p_param);
      break;

    case BTIF_QUEUE_ADVANCE_EVT:
      queue_int_advance();
      break;
  }

  if (stack_manager_get_interface()->get_stack_is_running())
    btif_queue_connect_next();
}

/*******************************************************************************
 *
 * Function         btif_queue_connect
 *
 * Description      Add a new connection to the queue and trigger the next
 *                  scheduled connection.
 *
 * Returns          BT_STATUS_SUCCESS if successful
 *
 ******************************************************************************/
bt_status_t btif_queue_connect(uint16_t uuid, const bt_bdaddr_t* bda,
                               btif_connect_cb_t connect_cb) {
  connect_node_t node;
  memset(&node, 0, sizeof(connect_node_t));
  memcpy(&node.bda, bda, sizeof(bt_bdaddr_t));
  node.uuid = uuid;
  node.connect_cb = connect_cb;

  return btif_transfer_context(queue_int_handle_evt, BTIF_QUEUE_CONNECT_EVT,
                               (char*)&node, sizeof(connect_node_t), NULL);
}

/*******************************************************************************
 *
 * Function         btif_queue_advance
 *
 * Description      Clear the queue's busy status and advance to the next
 *                  scheduled connection.
 *
 * Returns          void
 *
 ******************************************************************************/
void btif_queue_advance() {
  btif_transfer_context(queue_int_handle_evt, BTIF_QUEUE_ADVANCE_EVT, NULL, 0,
                        NULL);
}

// This function dispatches the next pending connect request. It is called from
// stack_manager when the stack comes up.
bt_status_t btif_queue_connect_next(void) {
  if (!connect_queue || list_is_empty(connect_queue)) return BT_STATUS_FAIL;

  connect_node_t* p_head = (connect_node_t*)list_front(connect_queue);

  // If the queue is currently busy, we return success anyway,
  // since the connection has been queued...
  if (p_head->busy) return BT_STATUS_SUCCESS;

  p_head->busy = true;
  return p_head->connect_cb(&p_head->bda, p_head->uuid);
}

/*******************************************************************************
 *
 * Function         btif_queue_release
 *
 * Description      Free up all the queue nodes and set the queue head to NULL
 *
 * Returns          void
 *
 ******************************************************************************/
void btif_queue_release() {
  list_free(connect_queue);
  connect_queue = NULL;
}