/*
   Copyright (c) 2013 Red Hat, Inc. <http://www.redhat.com>
   This file is part of GlusterFS.

   This file is licensed to you under your choice of the GNU Lesser
   General Public License, version 3 or any later version (LGPLv3 or
   later), or the GNU General Public License, version 2 (GPLv2), in all
   cases as published by the Free Software Foundation.
*/

#include "changelog-mem-types.h"
#include "gf-changelog-helpers.h"

ssize_t gf_changelog_read_path (int fd, char *buffer, size_t bufsize)
{
        return read (fd, buffer, bufsize);
}

size_t
gf_changelog_write (int fd, char *buffer, size_t len)
{
        ssize_t size = 0;
        size_t writen = 0;

        while (writen < len) {
                size = write (fd,
                              buffer + writen, len - writen);
                if (size <= 0)
                        break;

                writen += size;
        }

        return writen;
}

void
gf_rfc3986_encode (unsigned char *s, char *enc, char *estr)
{
        for (; *s; s++) {
                if (estr[*s])
                        sprintf(enc, "%c", estr[*s]);
                else
                        sprintf(enc, "%%%02X", *s);
                while (*++enc);
        }
}

/**
 * thread safe version of readline with buffering
 * (taken from Unix Network Programming Volume I, W.R. Stevens)
 *
 * This is favoured over fgets() as we'd need to ftruncate()
 * (see gf_changelog_scan() API) to record new changelog files.
 * stream open functions does have a truncate like api (although
 * that can be done via @fflush(fp), @ftruncate(fd) and @fseek(fp),
 * but this involves mixing POSIX file descriptors and stream FILE *).
 *
 * NOTE: This implmentation still does work with more than one fd's
 *       used to perform gf_readline(). For this very reason it's not
 *       made a part of libglusterfs.
 */

static pthread_key_t rl_key;
static pthread_once_t rl_once = PTHREAD_ONCE_INIT;

static void
readline_destructor (void *ptr)
{
        GF_FREE (ptr);
}

static void
readline_once (void)
{
        pthread_key_create (&rl_key, readline_destructor);
}

static ssize_t
my_read (read_line_t *tsd, int fd, char *ptr)
{
        if (tsd->rl_cnt <= 0) {
                if ( (tsd->rl_cnt = read (fd, tsd->rl_buf, MAXLINE)) < 0 )
                        return -1;
                else if (tsd->rl_cnt == 0)
                        return 0;
                tsd->rl_bufptr = tsd->rl_buf;
        }

        tsd->rl_cnt--;
        *ptr = *tsd->rl_bufptr++;
        return 1;
}

static int
gf_readline_init_once (read_line_t **tsd)
{
        if (pthread_once (&rl_once, readline_once) != 0)
                return -1;

        *tsd = pthread_getspecific (rl_key);
        if (*tsd)
                goto out;

        *tsd = GF_CALLOC (1, sizeof (**tsd),
                          gf_changelog_mt_libgfchangelog_rl_t);
        if (!*tsd)
                return -1;

        if (pthread_setspecific (rl_key, *tsd) != 0)
                return -1;

 out:
        return 0;
}

ssize_t
gf_readline (int fd, void *vptr, size_t maxlen)
{
        size_t       n   = 0;
        size_t       rc  = 0;
        char         c   = ' ';
        char        *ptr = NULL;
        read_line_t *tsd = NULL;

        if (gf_readline_init_once (&tsd))
                return -1;

        ptr = vptr;
        for (n = 1; n < maxlen; n++) {
                if ( (rc = my_read (tsd, fd, &c)) == 1 ) {
                        *ptr++ = c;
                        if (c == '\n')
                                break;
                } else if (rc == 0) {
                        *ptr = '\0';
                        return (n - 1);
                } else
                        return -1;
        }

        *ptr = '\0';
        return n;

}

off_t
gf_lseek (int fd, off_t offset, int whence)
{
        off_t        off = 0;
        read_line_t *tsd = NULL;

        if (gf_readline_init_once (&tsd))
                return -1;

        if ( (off = lseek (fd, offset, whence)) == -1)
                return -1;

        tsd->rl_cnt = 0;
        tsd->rl_bufptr = tsd->rl_buf;

        return off;
}

int
gf_ftruncate (int fd, off_t length)
{
        read_line_t *tsd = NULL;

        if (gf_readline_init_once (&tsd))
                return -1;

        if (ftruncate (fd, 0))
                return -1;

        tsd->rl_cnt = 0;
        tsd->rl_bufptr = tsd->rl_buf;

        return 0;
}