mpd/src/input/TextInputStream.cxx

/*
 * Copyright 2003-2017 The Music Player Daemon Project
 * http://www.musicpd.org
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */

#include "config.h"
#include "TextInputStream.hxx"
#include "InputStream.hxx"
#include "util/TextFile.hxx"
#include "Log.hxx"

#include <stdexcept>

#include <assert.h>

TextInputStream::TextInputStream(InputStreamPtr &&_is)
	:is(std::move(_is)) {}

TextInputStream::~TextInputStream() {}

char *
TextInputStream::ReadLine()
{
	char *line = ReadBufferedLine(buffer);
	if (line != nullptr)
		return line;

	buffer.Shift();

	while (true) {
		auto dest = buffer.Write();
		if (dest.size < 2) {
			/* line too long: terminate the current
			   line */

			assert(!dest.empty());
			dest[0] = 0;
			line = buffer.Read().data;
			buffer.Clear();
			return line;
		}

		/* reserve one byte for the null terminator if the
		   last line is not terminated by a newline
		   character */
		--dest.size;

		size_t nbytes;

		try {
			nbytes = is->LockRead(dest.data, dest.size);
		} catch (const std::runtime_error &e) {
			LogError(e);
			return nullptr;
		}

		buffer.Append(nbytes);

		line = ReadBufferedLine(buffer);
		if (line != nullptr)
			return line;

		if (nbytes == 0) {
			/* end of file: see if there's an unterminated
			   line */

			dest = buffer.Write();
			assert(!dest.empty());
			dest[0] = 0;

			auto r = buffer.Read();
			buffer.Clear();
			return r.empty()
				? nullptr
				: r.data;
		}
	}
}