/*      $OpenBSD: file.c,v 1.17 2021/12/15 19:22:44 tb Exp $    */

/*-
 * Copyright (c) 1999 James Howard and Dag-Erling Coïdan Smørgrav
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <sys/stat.h>
#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <limits.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <zlib.h>

#include "grep.h"

static char      fname[PATH_MAX];
static char     *lnbuf;
static size_t    lnbufsize;

#define FILE_STDIO      0
#define FILE_MMAP       1
#define FILE_GZIP       2

struct file {
        int      type;
        int      noseek;
        FILE    *f;
        mmf_t   *mmf;
        gzFile   gzf;
};

#ifndef NOZ
static char *
gzfgetln(gzFile f, size_t *len)
{
        size_t          n;
        int             c;

        for (n = 0; ; ++n) {
                c = gzgetc(f);
                if (c == -1) {
                        const char *gzerrstr;
                        int gzerr;

                        if (gzeof(f))
                                break;

                        gzerrstr = gzerror(f, &gzerr);
                        if (gzerr == Z_ERRNO)
                                err(2, "%s", fname);
                        else
                                errx(2, "%s: %s", fname, gzerrstr);
                }
                if (n >= lnbufsize) {
                        lnbufsize *= 2;
                        lnbuf = grep_realloc(lnbuf, ++lnbufsize);
                }
                if (c == '\n')
                        break;
                lnbuf[n] = c;
        }

        if (gzeof(f) && n == 0)
                return NULL;
        *len = n;
        return lnbuf;
}
#endif

file_t *
grep_fdopen(int fd)
{
        file_t *f;
        struct stat sb;

        if (fd == STDIN_FILENO)
                snprintf(fname, sizeof fname, "(standard input)");
        else if (fname[0] == '\0')
                snprintf(fname, sizeof fname, "(fd %d)", fd);

        if (fstat(fd, &sb) == -1)
                return NULL;
        if (S_ISDIR(sb.st_mode)) {
                errno = EISDIR;
                return NULL;
        }

        f = grep_malloc(sizeof *f);

#ifndef NOZ
        if (Zflag) {
                f->type = FILE_GZIP;
                f->noseek = lseek(fd, 0L, SEEK_SET) == -1;
                if ((f->gzf = gzdopen(fd, "r")) != NULL)
                        return f;
        }
#endif
        f->noseek = isatty(fd);
#ifndef SMALL
        /* try mmap first; if it fails, try stdio */
        if (!f->noseek && (f->mmf = mmopen(fd, &sb)) != NULL) {
                f->type = FILE_MMAP;
                return f;
        }
#endif
        f->type = FILE_STDIO;
        if ((f->f = fdopen(fd, "r")) != NULL)
                return f;

        free(f);
        return NULL;
}

file_t *
grep_open(char *path)
{
        file_t *f;
        int fd;

        snprintf(fname, sizeof fname, "%s", path);

        if ((fd = open(fname, O_RDONLY)) == -1)
                return NULL;

        f = grep_fdopen(fd);
        if (f == NULL)
                close(fd);
        return f;
}

int
grep_bin_file(file_t *f)
{
        if (f->noseek)
                return 0;

        switch (f->type) {
        case FILE_STDIO:
                return bin_file(f->f);
#ifndef SMALL
        case FILE_MMAP:
                return mmbin_file(f->mmf);
#endif
#ifndef NOZ
        case FILE_GZIP:
                return gzbin_file(f->gzf);
#endif
        default:
                /* can't happen */
                errx(2, "invalid file type");
        }
}

char *
grep_fgetln(file_t *f, size_t *l)
{
        switch (f->type) {
        case FILE_STDIO:
                if ((*l = getline(&lnbuf, &lnbufsize, f->f)) == -1) {
                        if (ferror(f->f))
                                err(2, "%s: getline", fname);
                        else
                                return NULL;
                }
                return lnbuf;
#ifndef SMALL
        case FILE_MMAP:
                return mmfgetln(f->mmf, l);
#endif
#ifndef NOZ
        case FILE_GZIP:
                return gzfgetln(f->gzf, l);
#endif
        default:
                /* can't happen */
                errx(2, "invalid file type");
        }
}

void
grep_close(file_t *f)
{
        switch (f->type) {
        case FILE_STDIO:
                fclose(f->f);
                break;
#ifndef SMALL
        case FILE_MMAP:
                mmclose(f->mmf);
                break;
#endif
#ifndef NOZ
        case FILE_GZIP:
                gzclose(f->gzf);
                break;
#endif
        default:
                /* can't happen */
                errx(2, "invalid file type");
        }
        free(f);
}