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 #pragma once
18 
19 #include <thread>
20 
21 #include <android-base/macros.h>
22 #include <android-base/result.h>
23 #include <android-base/unique_fd.h>
24 #include <utils/Errors.h>
25 #include <utils/RefBase.h>
26 #include <ostream>
27 
28 #include "NullableOStream.h"
29 
30 namespace android {
31 namespace lshal {
32 
33 /**
34  * Creates a pipe and spawns a thread that relays any data
35  * written to the "write"-end of the pair to the specified output stream "os".
36  */
37 struct PipeRelay {
38     static android::base::Result<std::unique_ptr<PipeRelay>> create(
39             std::ostream& os, const NullableOStream<std::ostream>& err, const std::string& fqName);
40     ~PipeRelay();
41 
42     // Returns the file descriptor corresponding to the "write"-end of the
43     // connection.
fdPipeRelay44     android::base::borrowed_fd fd() const { return mWrite; }
45 
46 private:
47     PipeRelay() = default;
48     DISALLOW_COPY_AND_ASSIGN(PipeRelay);
49     static void thread(android::base::unique_fd rfd, android::base::unique_fd rfdTrigger,
50                        std::ostream* out, const NullableOStream<std::ostream>* err,
51                        std::string fqName);
52 
53     android::base::unique_fd mWrite;
54     android::base::unique_fd mWriteTrigger;
55     std::unique_ptr<std::thread> mThread;
56 };
57 
58 }  // namespace lshal
59 }  // namespace android
60