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1 /*
2  * Copyright 2017 The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 
17 #include <cstdint>
18 #include <list>
19 #include <unordered_map>
20 #include <unordered_set>
21 #include <vector>
22 
23 #include "bta/include/bta_gatt_api.h"
24 
25 /* BTA GATTC implementation does not allow for multiple commands queuing. So one
26  * client making calls to BTA_GATTC_ReadCharacteristic, BTA_GATTC_ReadCharDescr,
27  * BTA_GATTC_WriteCharValue, BTA_GATTC_WriteCharDescr must wait for the callacks
28  * before scheduling next operation.
29  *
30  * Methods below can be used as replacement to BTA_GATTC_* in BTA app. They do
31  * queue the commands if another command is currently being executed.
32  *
33  * If you decide to use those methods in your app, make sure to not mix it with
34  * existing BTA_GATTC_* API.
35  */
36 class BtaGattQueue {
37  public:
38   static void Clean(uint16_t conn_id);
39   static void ReadCharacteristic(uint16_t conn_id, uint16_t handle,
40                                  GATT_READ_OP_CB cb, void* cb_data);
41   static void ReadDescriptor(uint16_t conn_id, uint16_t handle,
42                              GATT_READ_OP_CB cb, void* cb_data);
43   static void WriteCharacteristic(uint16_t conn_id, uint16_t handle,
44                                   std::vector<uint8_t> value,
45                                   tGATT_WRITE_TYPE write_type,
46                                   GATT_WRITE_OP_CB cb, void* cb_data);
47   static void WriteDescriptor(uint16_t conn_id, uint16_t handle,
48                               std::vector<uint8_t> value,
49                               tGATT_WRITE_TYPE write_type, GATT_WRITE_OP_CB cb,
50                               void* cb_data);
51   static void ConfigureMtu(uint16_t conn_id, uint16_t mtu);
52 
53   /* Holds pending GATT operations */
54   struct gatt_operation {
55     uint8_t type;
56     uint16_t handle;
57     GATT_READ_OP_CB read_cb;
58     void* read_cb_data;
59     GATT_WRITE_OP_CB write_cb;
60     void* write_cb_data;
61     GATT_CONFIGURE_MTU_OP_CB mtu_cb;
62     void* mtu_cb_data;
63 
64     /* write-specific fields */
65     tGATT_WRITE_TYPE write_type;
66     std::vector<uint8_t> value;
67   };
68 
69  private:
70   static void mark_as_not_executing(uint16_t conn_id);
71   static void gatt_execute_next_op(uint16_t conn_id);
72   static void gatt_read_op_finished(uint16_t conn_id, tGATT_STATUS status,
73                                     uint16_t handle, uint16_t len,
74                                     uint8_t* value, void* data);
75   static void gatt_write_op_finished(uint16_t conn_id, tGATT_STATUS status,
76                                      uint16_t handle, void* data);
77   static void gatt_configure_mtu_op_finished(uint16_t conn_id,
78                                              tGATT_STATUS status, void* data);
79 
80   // maps connection id to operations waiting for execution
81   static std::unordered_map<uint16_t, std::list<gatt_operation>> gatt_op_queue;
82   // contain connection ids that currently execute operations
83   static std::unordered_set<uint16_t> gatt_op_queue_executing;
84 };
85