1 | // |
2 | // Pipe.h |
3 | // |
4 | // Library: Foundation |
5 | // Package: Processes |
6 | // Module: Pipe |
7 | // |
8 | // Definition of the Pipe class. |
9 | // |
10 | // Copyright (c) 2004-2006, Applied Informatics Software Engineering GmbH. |
11 | // and Contributors. |
12 | // |
13 | // SPDX-License-Identifier: BSL-1.0 |
14 | // |
15 | |
16 | |
17 | #ifndef Foundation_Pipe_INCLUDED |
18 | #define Foundation_Pipe_INCLUDED |
19 | |
20 | |
21 | #include "Poco/Foundation.h" |
22 | #include "Poco/PipeImpl.h" |
23 | |
24 | |
25 | namespace Poco { |
26 | |
27 | |
28 | class Foundation_API Pipe |
29 | /// This class implements an anonymous pipe. |
30 | /// |
31 | /// Pipes are a common method of inter-process communication - |
32 | /// on Unix, pipes are the oldest form of IPC. |
33 | /// |
34 | /// A pipe is a half-duplex communication channel, which means |
35 | /// that data only flows in one direction. |
36 | /// Pipes have a read-end and a write-end. One process writes to |
37 | /// the pipe and another process reads the data written by |
38 | /// its peer. |
39 | /// Read and write operations are always synchronous. A read will |
40 | /// block until data is available and a write will block until |
41 | /// the reader reads the data. |
42 | /// |
43 | /// The sendBytes() and readBytes() methods of Pipe are usually |
44 | /// used through a PipeOutputStream or PipeInputStream and are |
45 | /// not called directly. |
46 | /// |
47 | /// Pipe objects have value semantics; the actual work is delegated |
48 | /// to a reference-counted PipeImpl object. |
49 | { |
50 | public: |
51 | typedef PipeImpl::Handle Handle; /// The read/write handle or file descriptor. |
52 | |
53 | enum CloseMode /// used by close() |
54 | { |
55 | CLOSE_READ = 0x01, /// Close reading end of pipe. |
56 | CLOSE_WRITE = 0x02, /// Close writing end of pipe. |
57 | CLOSE_BOTH = 0x03 /// Close both ends of pipe. |
58 | }; |
59 | |
60 | Pipe(); |
61 | /// Creates the Pipe. |
62 | /// |
63 | /// Throws a CreateFileException if the pipe cannot be |
64 | /// created. |
65 | |
66 | Pipe(const Pipe& pipe); |
67 | /// Creates the Pipe using the PipeImpl from another one. |
68 | |
69 | ~Pipe(); |
70 | /// Closes and destroys the Pipe. |
71 | |
72 | Pipe& operator = (const Pipe& pipe); |
73 | /// Releases the Pipe's PipeImpl and assigns another one. |
74 | |
75 | int writeBytes(const void* buffer, int length); |
76 | /// Sends the contents of the given buffer through |
77 | /// the pipe. Blocks until the receiver is ready |
78 | /// to read the data. |
79 | /// |
80 | /// Returns the number of bytes sent. |
81 | /// |
82 | /// Throws a WriteFileException if the data cannot be written. |
83 | |
84 | int readBytes(void* buffer, int length); |
85 | /// Receives data from the pipe and stores it |
86 | /// in buffer. Up to length bytes are received. |
87 | /// Blocks until data becomes available. |
88 | /// |
89 | /// Returns the number of bytes received, or 0 |
90 | /// if the pipe has been closed. |
91 | /// |
92 | /// Throws a ReadFileException if nothing can be read. |
93 | |
94 | Handle readHandle() const; |
95 | /// Returns the read handle or file descriptor |
96 | /// for the Pipe. For internal use only. |
97 | |
98 | Handle writeHandle() const; |
99 | /// Returns the write handle or file descriptor |
100 | /// for the Pipe. For internal use only. |
101 | |
102 | void close(CloseMode mode = CLOSE_BOTH); |
103 | /// Depending on the argument, closes either the |
104 | /// reading end, the writing end, or both ends |
105 | /// of the Pipe. |
106 | |
107 | private: |
108 | PipeImpl* _pImpl; |
109 | }; |
110 | |
111 | |
112 | // |
113 | // inlines |
114 | // |
115 | inline int Pipe::writeBytes(const void* buffer, int length) |
116 | { |
117 | return _pImpl->writeBytes(buffer, length); |
118 | } |
119 | |
120 | |
121 | inline int Pipe::readBytes(void* buffer, int length) |
122 | { |
123 | return _pImpl->readBytes(buffer, length); |
124 | } |
125 | |
126 | |
127 | inline Pipe::Handle Pipe::readHandle() const |
128 | { |
129 | return _pImpl->readHandle(); |
130 | } |
131 | |
132 | |
133 | inline Pipe::Handle Pipe::writeHandle() const |
134 | { |
135 | return _pImpl->writeHandle(); |
136 | } |
137 | |
138 | |
139 | } // namespace Poco |
140 | |
141 | |
142 | #endif // Foundation_Pipe_INCLUDED |
143 | |