1 /*
2  * Copyright 2019 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 #pragma once
17 
18 #include "common/bidi_queue.h"
19 #include "common/callback.h"
20 #include "hci/acl_manager.h"
21 #include "l2cap/cid.h"
22 #include "os/handler.h"
23 #include "packet/base_packet_builder.h"
24 #include "packet/packet_view.h"
25 
26 namespace bluetooth {
27 namespace l2cap {
28 namespace classic {
29 
30 namespace internal {
31 class FixedChannelImpl;
32 }  // namespace internal
33 
34 /**
35  * L2CAP fixed channel object. When a new object is created, it must be
36  * acquired through calling {@link FixedChannel#Acquire()} within X seconds.
37  * Otherwise, {@link FixedChannel#Release()} will be called automatically.
38  *
39  */
40 class FixedChannel {
41  public:
42   // Should only be constructed by modules that have access to LinkManager
FixedChannel(std::shared_ptr<internal::FixedChannelImpl> impl,os::Handler * l2cap_handler)43   FixedChannel(std::shared_ptr<internal::FixedChannelImpl> impl, os::Handler* l2cap_handler)
44       : impl_(std::move(impl)), l2cap_handler_(l2cap_handler) {
45     ASSERT(impl_ != nullptr);
46     ASSERT(l2cap_handler_ != nullptr);
47   }
48 
49   hci::Address GetDevice() const;
50 
51   /**
52    * Register close callback. If close callback is registered, when a channel is closed, the channel's resource will
53    * only be freed after on_close callback is invoked. Otherwise, if no on_close callback is registered, the channel's
54    * resource will be freed immediately after closing.
55    *
56    * @param user_handler The handler used to invoke the callback on
57    * @param on_close_callback The callback invoked upon channel closing.
58    */
59   using OnCloseCallback = common::OnceCallback<void(hci::ErrorCode)>;
60   void RegisterOnCloseCallback(os::Handler* user_handler, OnCloseCallback on_close_callback);
61 
62   /**
63    * Indicate that this Fixed Channel is being used. This will prevent ACL connection from being disconnected.
64    */
65   void Acquire();
66 
67   /**
68    * Indicate that this Fixed Channel is no longer being used. ACL connection will be disconnected after
69    * kLinkIdleDisconnectTimeout if no other DynamicChannel is connected or no other Fixed Channel is  using this
70    * ACL connection. However a module can still receive data on this channel as long as it remains open.
71    */
72   void Release();
73 
74   /**
75    * This method will retrieve the data channel queue to send and receive packets.
76    *
77    * {@see BidiQueueEnd}
78    *
79    * @return The upper end of a bi-directional queue.
80    */
81   common::BidiQueueEnd<packet::BasePacketBuilder, packet::PacketView<packet::kLittleEndian>>* GetQueueUpEnd() const;
82 
83  private:
84   std::shared_ptr<internal::FixedChannelImpl> impl_;
85   os::Handler* l2cap_handler_;
86 };
87 
88 }  // namespace classic
89 }  // namespace l2cap
90 }  // namespace bluetooth
91