lib/input/stdin.cc

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//
// nis-util - NIS Administration Utilities
// Copyright (C) 2012 Peter Miller
//
// 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, see <http://www.gnu.org/licenses/>.
//

#include <lib/ac/stdio.h>
#include <lib/ac/unistd.h>
#include <libexplain/fread.h>

#include <lib/input/stdin.h>


input_stdin::~input_stdin()
{
}


input_stdin::input_stdin() :
    filename("stdin"),
    line_number(1)
{
    // Try reading /proc/self/fd/0 to obtain a more useful file name.
    char lbuf[2000];
    int n = readlink("/proc/self/fd/0", lbuf, sizeof(lbuf));
    if (n > 0 && lbuf[0] == '/')
        filename = rcstring(lbuf, n);
}


bool
input_stdin::candidate(const rcstring &filename)
{
    if (filename.empty())
        return true;
    if (filename == "-")
        return true;
    if (filename == "/dev/stdin")
        return true;
    if (filename == "/dev/fd/0")
        return true;
    if (filename == "/proc/self/fd/0")
        return true;
    return false;
}


input_stdin::pointer
input_stdin::create(void)
{
    return pointer(new input_stdin());
}


size_t
input_stdin::read_inner(source_location &locn, void *data, size_t data_size)
{
    // FIXME: if stdin is line buffered, should we be too?
    locn = source_location(filename, line_number);
    size_t nbytes = explain_fread_or_die(data, 1, data_size, stdin);
    line_number += count_newlines(data, nbytes);
    return nbytes;
}


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