1 /*
2  * Copyright (C) 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 #ifndef ANDROID_EMULATORCOMMCONN_COMMCONN_H
18 #define ANDROID_EMULATORCOMMCONN_COMMCONN_H
19 
20 #include <string>
21 #include <thread>
22 #include <vector>
23 
24 #include "VehicleHalProto.pb.h"
25 
26 namespace android {
27 namespace hardware {
28 namespace automotive {
29 namespace vehicle {
30 namespace V2_0 {
31 
32 namespace impl {
33 
34 /**
35  * MessageProcess is an interface implemented by VehicleEmulator to process messages received
36  * over a CommConn.
37  */
38 class MessageProcessor {
39    public:
40     virtual ~MessageProcessor() = default;
41 
42     /**
43      * Process a single message received over a CommConn. Populate the given respMsg with the reply
44      * message we should send.
45      */
46     virtual void processMessage(const vhal_proto::EmulatorMessage& rxMsg,
47                                 vhal_proto::EmulatorMessage* respMsg) = 0;
48 };
49 
50 /**
51  * This is a pure virtual interface that could start/stop and send message.
52  * This is implemented by CommConn and SocketComm.
53  */
54 class MessageSender {
55   public:
~MessageSender()56     virtual ~MessageSender() {}
57 
58     /**
59      * Starts the read thread reading messages from this connection.
60      */
61     virtual void start() = 0;
62 
63     /**
64      * Closes a connection if it is open.
65      */
66     virtual void stop() = 0;
67 
68     /**
69      * Serializes and sends the given message to the other side.
70      */
71     virtual void sendMessage(const vhal_proto::EmulatorMessage& msg) = 0;
72 };
73 
74 /**
75  * This is the interface that both PipeComm and SocketComm use to represent a connection. The
76  * connection will listen for commands on a separate 'read' thread.
77  */
78 class CommConn : public MessageSender {
79   public:
CommConn(MessageProcessor * messageProcessor)80     CommConn(MessageProcessor* messageProcessor) : mMessageProcessor(messageProcessor) {}
81 
~CommConn()82     virtual ~CommConn() {}
83 
84     /**
85      * Start the read thread reading messages from this connection.
86      */
87     void start() override;
88 
89     /**
90      * Closes a connection if it is open.
91      */
92     void stop() override;
93 
94     /**
95      * Returns true if the connection is open and available to send/receive.
96      */
97     virtual bool isOpen() = 0;
98 
99     /**
100      * Serialized and send the given message to the other side.
101      */
102     void sendMessage(const vhal_proto::EmulatorMessage& msg) final;
103 
104   protected:
105     MessageProcessor* mMessageProcessor;
106 
107   private:
108     std::unique_ptr<std::thread> mReadThread;
109     std::mutex mSendMessageLock;
110 
111     /**
112      * A thread that reads messages in a loop, and responds. You can stop this thread by calling
113      * stop().
114      */
115     void readThread();
116 
117     /**
118      * Blocking call to read data from the connection.
119      *
120      * @return std::vector<uint8_t> Serialized protobuf data received from emulator.  This will be
121      *              an empty vector if the connection was closed or some other error occurred.
122      */
123     virtual std::vector<uint8_t> read() = 0;
124 
125     /**
126      * Transmits a string of data to the emulator.
127      *
128      * @param data Serialized protobuf data to transmit.
129      *
130      * @return int Number of bytes transmitted, or -1 if failed.
131      */
132     virtual int write(const std::vector<uint8_t>& data) = 0;
133 };
134 
135 }  // namespace impl
136 
137 }  // namespace V2_0
138 }  // namespace vehicle
139 }  // namespace automotive
140 }  // namespace hardware
141 }  // namespace android
142 
143 #endif  // ANDROID_EMULATORCOMMCONN_COMMCONN_H
144