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145 lines
3.4 KiB
C++
145 lines
3.4 KiB
C++
//
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// Pipe.h
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//
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// $Id: //poco/1.4/Foundation/include/Poco/Pipe.h#1 $
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//
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// Library: Foundation
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// Package: Processes
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// Module: Pipe
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//
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// Definition of the Pipe class.
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//
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// Copyright (c) 2004-2006, Applied Informatics Software Engineering GmbH.
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// and Contributors.
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//
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// SPDX-License-Identifier: BSL-1.0
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//
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#ifndef Foundation_Pipe_INCLUDED
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#define Foundation_Pipe_INCLUDED
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#include "Poco/Foundation.h"
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#include "Poco/PipeImpl.h"
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namespace Poco {
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class Foundation_API Pipe
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/// This class implements an anonymous pipe.
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///
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/// Pipes are a common method of inter-process communication -
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/// on Unix, pipes are the oldest form of IPC.
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///
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/// A pipe is a half-duplex communication channel, which means
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/// that data only flows in one direction.
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/// Pipes have a read-end and a write-end. One process writes to
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/// the pipe and another process reads the data written by
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/// its peer.
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/// Read and write operations are always synchronous. A read will
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/// block until data is available and a write will block until
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/// the reader reads the data.
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///
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/// The sendBytes() and readBytes() methods of Pipe are usually
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/// used through a PipeOutputStream or PipeInputStream and are
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/// not called directly.
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///
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/// Pipe objects have value semantics; the actual work is delegated
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/// to a reference-counted PipeImpl object.
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{
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public:
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typedef PipeImpl::Handle Handle; /// The read/write handle or file descriptor.
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enum CloseMode /// used by close()
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{
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CLOSE_READ = 0x01, /// Close reading end of pipe.
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CLOSE_WRITE = 0x02, /// Close writing end of pipe.
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CLOSE_BOTH = 0x03 /// Close both ends of pipe.
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};
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Pipe();
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/// Creates the Pipe.
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///
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/// Throws a CreateFileException if the pipe cannot be
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/// created.
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Pipe(const Pipe& pipe);
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/// Creates the Pipe using the PipeImpl from another one.
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~Pipe();
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/// Closes and destroys the Pipe.
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Pipe& operator = (const Pipe& pipe);
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/// Releases the Pipe's PipeImpl and assigns another one.
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int writeBytes(const void* buffer, int length);
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/// Sends the contents of the given buffer through
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/// the pipe. Blocks until the receiver is ready
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/// to read the data.
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///
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/// Returns the number of bytes sent.
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///
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/// Throws a WriteFileException if the data cannot be written.
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int readBytes(void* buffer, int length);
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/// Receives data from the pipe and stores it
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/// in buffer. Up to length bytes are received.
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/// Blocks until data becomes available.
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///
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/// Returns the number of bytes received, or 0
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/// if the pipe has been closed.
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///
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/// Throws a ReadFileException if nothing can be read.
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Handle readHandle() const;
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/// Returns the read handle or file descriptor
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/// for the Pipe. For internal use only.
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Handle writeHandle() const;
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/// Returns the write handle or file descriptor
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/// for the Pipe. For internal use only.
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void close(CloseMode mode = CLOSE_BOTH);
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/// Depending on the argument, closes either the
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/// reading end, the writing end, or both ends
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/// of the Pipe.
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private:
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PipeImpl* _pImpl;
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};
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//
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// inlines
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//
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inline int Pipe::writeBytes(const void* buffer, int length)
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{
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return _pImpl->writeBytes(buffer, length);
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}
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inline int Pipe::readBytes(void* buffer, int length)
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{
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return _pImpl->readBytes(buffer, length);
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}
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inline Pipe::Handle Pipe::readHandle() const
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{
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return _pImpl->readHandle();
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}
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inline Pipe::Handle Pipe::writeHandle() const
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{
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return _pImpl->writeHandle();
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}
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} // namespace Poco
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#endif // Foundation_Pipe_INCLUDED
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