/Users/eugenesiegel/btc/bitcoin/src/util/tokenpipe.h
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1 | | // Copyright (c) 2021 The Bitcoin Core developers |
2 | | // Distributed under the MIT software license, see the accompanying |
3 | | // file COPYING or http://www.opensource.org/licenses/mit-license.php. |
4 | | |
5 | | #ifndef BITCOIN_UTIL_TOKENPIPE_H |
6 | | #define BITCOIN_UTIL_TOKENPIPE_H |
7 | | |
8 | | #ifndef WIN32 |
9 | | |
10 | | #include <cstdint> |
11 | | #include <optional> |
12 | | |
13 | | /** One end of a token pipe. */ |
14 | | class TokenPipeEnd |
15 | | { |
16 | | private: |
17 | | int m_fd = -1; |
18 | | |
19 | | public: |
20 | | TokenPipeEnd(int fd = -1); |
21 | | ~TokenPipeEnd(); |
22 | | |
23 | | /** Return value constants for TokenWrite and TokenRead. */ |
24 | | enum Status { |
25 | | TS_ERR = -1, //!< I/O error |
26 | | TS_EOS = -2, //!< Unexpected end of stream |
27 | | }; |
28 | | |
29 | | /** Write token to endpoint. |
30 | | * |
31 | | * @returns 0 If successful. |
32 | | * <0 if error: |
33 | | * TS_ERR If an error happened. |
34 | | * TS_EOS If end of stream happened. |
35 | | */ |
36 | | int TokenWrite(uint8_t token); |
37 | | |
38 | | /** Read token from endpoint. |
39 | | * |
40 | | * @returns >=0 Token value, if successful. |
41 | | * <0 if error: |
42 | | * TS_ERR If an error happened. |
43 | | * TS_EOS If end of stream happened. |
44 | | */ |
45 | | int TokenRead(); |
46 | | |
47 | | /** Explicit close function. |
48 | | */ |
49 | | void Close(); |
50 | | |
51 | | /** Return whether endpoint is open. |
52 | | */ |
53 | 0 | bool IsOpen() { return m_fd != -1; } |
54 | | |
55 | | // Move-only class. |
56 | | TokenPipeEnd(TokenPipeEnd&& other) |
57 | 0 | { |
58 | 0 | m_fd = other.m_fd; |
59 | 0 | other.m_fd = -1; |
60 | 0 | } |
61 | | TokenPipeEnd& operator=(TokenPipeEnd&& other) |
62 | 102k | { |
63 | 102k | Close(); |
64 | 102k | m_fd = other.m_fd; |
65 | 102k | other.m_fd = -1; |
66 | 102k | return *this; |
67 | 102k | } |
68 | | TokenPipeEnd(const TokenPipeEnd&) = delete; |
69 | | TokenPipeEnd& operator=(const TokenPipeEnd&) = delete; |
70 | | }; |
71 | | |
72 | | /** An interprocess or interthread pipe for sending tokens (one-byte values) |
73 | | * over. |
74 | | */ |
75 | | class TokenPipe |
76 | | { |
77 | | private: |
78 | | int m_fds[2] = {-1, -1}; |
79 | | |
80 | 51.2k | TokenPipe(int fds[2]) : m_fds{fds[0], fds[1]} {} |
81 | | |
82 | | public: |
83 | | ~TokenPipe(); |
84 | | |
85 | | /** Create a new pipe. |
86 | | * @returns The created TokenPipe, or an empty std::nullopt in case of error. |
87 | | */ |
88 | | static std::optional<TokenPipe> Make(); |
89 | | |
90 | | /** Take the read end of this pipe. This can only be called once, |
91 | | * as the object will be moved out. |
92 | | */ |
93 | | TokenPipeEnd TakeReadEnd(); |
94 | | |
95 | | /** Take the write end of this pipe. This should only be called once, |
96 | | * as the object will be moved out. |
97 | | */ |
98 | | TokenPipeEnd TakeWriteEnd(); |
99 | | |
100 | | /** Close and end of the pipe that hasn't been moved out. |
101 | | */ |
102 | | void Close(); |
103 | | |
104 | | // Move-only class. |
105 | | TokenPipe(TokenPipe&& other) |
106 | 51.2k | { |
107 | 153k | for (int i = 0; i < 2; ++i102k ) { |
108 | 102k | m_fds[i] = other.m_fds[i]; |
109 | 102k | other.m_fds[i] = -1; |
110 | 102k | } |
111 | 51.2k | } |
112 | | TokenPipe& operator=(TokenPipe&& other) |
113 | 0 | { |
114 | 0 | Close(); |
115 | 0 | for (int i = 0; i < 2; ++i) { |
116 | 0 | m_fds[i] = other.m_fds[i]; |
117 | 0 | other.m_fds[i] = -1; |
118 | 0 | } |
119 | 0 | return *this; |
120 | 0 | } |
121 | | TokenPipe(const TokenPipe&) = delete; |
122 | | TokenPipe& operator=(const TokenPipe&) = delete; |
123 | | }; |
124 | | |
125 | | #endif // WIN32 |
126 | | |
127 | | #endif // BITCOIN_UTIL_TOKENPIPE_H |