142 lines
4.2 KiB
C++
142 lines
4.2 KiB
C++
/*
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* Copyright (c) 2003-2013, John Wiegley. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are
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* met:
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*
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* - Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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*
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* - Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* - Neither the name of New Artisans LLC nor the names of its
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* contributors may be used to endorse or promote products derived from
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* this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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/**
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* @addtogroup util
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*/
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/**
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* @file stream.h
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* @author John Wiegley, Omari Norman
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*
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* @ingroup util
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*
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* @brief A utility class for abstracting an output stream.
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*
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* Because Ledger might send output to a file, the console, or a pager
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* child process, different cleanup is needed for each scenario. This
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* file abstracts those various needs.
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*/
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#ifndef _STREAM_H
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#define _STREAM_H
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#include "utils.h"
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namespace ledger {
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/**
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* @brief An output stream
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*
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* A stream to output in Ledger may be going to one of three places:
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* to stdout, to a file, or to a pager. Construct an output_stream_t and
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* the stream will automatically be cleaned up upon destruction.
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*
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* This class suffers from "else-if-heimer's disease," see Marshall
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* Cline's "C++ FAQ Lite". Arguably this should be three different
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* classes, but that introduces additional unneeded complications.
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*/
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class output_stream_t
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{
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output_stream_t& operator=(const output_stream_t&);
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private:
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int pipe_to_pager_fd;
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public:
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/**
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* A pointer to the ostream. Don't delete this; the output_stream_t
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* class takes care of this.
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*/
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std::ostream * os;
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/**
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* Construct a new output_stream_t.
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*/
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output_stream_t() : pipe_to_pager_fd(-1), os(&std::cout) {
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TRACE_CTOR(output_stream_t, "");
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}
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/**
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* When copy-constructed, make the copy just be a new output stream. This
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* allows large classes to rely on their default copy-constructor without
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* worrying about pointer copying within output_stream_t.
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*/
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output_stream_t(const output_stream_t&)
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: pipe_to_pager_fd(-1), os(&std::cout) {
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TRACE_CTOR(output_stream_t, "copy");
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}
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/**
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* Destroys an output_stream_t. This deletes the dynamically
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* allocated ostream, if necessary. It also closes output file
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* descriptor, if necessary.
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*/
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~output_stream_t() {
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TRACE_DTOR(output_stream_t);
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close();
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}
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/**
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* Initialize the output stream object.
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*
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* @param output_file File to which to send output. If both this
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* and pager are set, output_file takes priority.
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*
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* @param pager_path Path to a pager. To not use a pager, leave this
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* empty.
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*/
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void initialize(const optional<path>& output_file = none,
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const optional<path>& pager_path = none);
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/**
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* Convertor to a standard ostream. This is used so that we can
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* stream directly to an object of type output_stream_t.
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*/
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operator std::ostream&() {
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return *os;
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}
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/**
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* Flushing function. A simple proxy for ostream's flush.
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*/
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void flush() {
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os->flush();
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}
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/**
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* Close the output stream, waiting on the pager process if necessary.
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*/
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void close();
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};
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} // namespace ledger
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#endif // _STREAM_H
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