/*      $NetBSD: citrus_mapper.c,v 1.10 2012/06/08 07:49:42 martin Exp $        */

/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c)2003 Citrus Project,
 * 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/types.h>
#include <sys/stat.h>
#include <sys/queue.h>

#include <assert.h>
#include <errno.h>
#include <limits.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "citrus_namespace.h"
#include "citrus_types.h"
#include "citrus_region.h"
#include "citrus_lock.h"
#include "citrus_memstream.h"
#include "citrus_bcs.h"
#include "citrus_mmap.h"
#include "citrus_module.h"
#include "citrus_hash.h"
#include "citrus_mapper.h"

#define _CITRUS_MAPPER_DIR      "mapper.dir"

#define CM_HASH_SIZE 101
#define REFCOUNT_PERSISTENT     -1

static pthread_rwlock_t         cm_lock = PTHREAD_RWLOCK_INITIALIZER;

struct _citrus_mapper_area {
        _CITRUS_HASH_HEAD(, _citrus_mapper, CM_HASH_SIZE)        ma_cache;
        char                                                    *ma_dir;
};

/*
 * _citrus_mapper_create_area:
 *      create mapper area
 */

int
_citrus_mapper_create_area(
    struct _citrus_mapper_area *__restrict *__restrict rma,
    const char *__restrict area)
{
        struct _citrus_mapper_area *ma;
        struct stat st;
        char path[PATH_MAX];
        int ret;

        WLOCK(&cm_lock);

        if (*rma != NULL) {
                ret = 0;
                goto quit;
        }

        snprintf(path, (size_t)PATH_MAX, "%s/%s", area, _CITRUS_MAPPER_DIR);

        ret = stat(path, &st);
        if (ret)
                goto quit;

        ma = malloc(sizeof(*ma));
        if (ma == NULL) {
                ret = errno;
                goto quit;
        }
        ma->ma_dir = strdup(area);
        if (ma->ma_dir == NULL) {
                ret = errno;
                free(ma);
                goto quit;
        }
        _CITRUS_HASH_INIT(&ma->ma_cache, CM_HASH_SIZE);

        *rma = ma;
        ret = 0;
quit:
        UNLOCK(&cm_lock);

        return (ret);
}


/*
 * lookup_mapper_entry:
 *      lookup mapper.dir entry in the specified directory.
 *
 * line format of iconv.dir file:
 *      mapper  module  arg
 * mapper : mapper name.
 * module : mapper module name.
 * arg    : argument for the module (generally, description file name)
 */

static int
lookup_mapper_entry(const char *dir, const char *mapname, void *linebuf,
    size_t linebufsize, const char **module, const char **variable)
{
        struct _region r;
        struct _memstream ms;
        const char *cp, *cq;
        char *p;
        char path[PATH_MAX];
        size_t len;
        int ret;

        /* create mapper.dir path */
        snprintf(path, (size_t)PATH_MAX, "%s/%s", dir, _CITRUS_MAPPER_DIR);

        /* open read stream */
        ret = _map_file(&r, path);
        if (ret)
                return (ret);

        _memstream_bind(&ms, &r);

        /* search the line matching to the map name */
        cp = _memstream_matchline(&ms, mapname, &len, 0);
        if (!cp) {
                ret = ENOENT;
                goto quit;
        }
        if (!len || len > linebufsize - 1) {
                ret = EINVAL;
                goto quit;
        }

        p = linebuf;
        /* get module name */
        *module = p;
        cq = _bcs_skip_nonws_len(cp, &len);
        strlcpy(p, cp, (size_t)(cq - cp + 1));
        p += cq - cp + 1;

        /* get variable */
        *variable = p;
        cp = _bcs_skip_ws_len(cq, &len);
        strlcpy(p, cp, len + 1);

        ret = 0;

quit:
        _unmap_file(&r);
        return (ret);
}

/*
 * mapper_close:
 *      simply close a mapper. (without handling hash)
 */
static void
mapper_close(struct _citrus_mapper *cm)
{
        if (cm->cm_module) {
                if (cm->cm_ops) {
                        if (cm->cm_closure)
                                (*cm->cm_ops->mo_uninit)(cm);
                        free(cm->cm_ops);
                }
                _citrus_unload_module(cm->cm_module);
        }
        free(cm->cm_traits);
        free(cm);
}

/*
 * mapper_open:
 *      simply open a mapper. (without handling hash)
 */
static int
mapper_open(struct _citrus_mapper_area *__restrict ma,
    struct _citrus_mapper * __restrict * __restrict rcm,
    const char * __restrict module,
    const char * __restrict variable)
{
        struct _citrus_mapper *cm;
        _citrus_mapper_getops_t getops;
        int ret;

        /* initialize mapper handle */
        cm = malloc(sizeof(*cm));
        if (!cm)
                return (errno);

        cm->cm_module = NULL;
        cm->cm_ops = NULL;
        cm->cm_closure = NULL;
        cm->cm_traits = NULL;
        cm->cm_refcount = 0;
        cm->cm_key = NULL;

        /* load module */
        ret = _citrus_load_module(&cm->cm_module, module);
        if (ret)
                goto err;

        /* get operators */
        getops = (_citrus_mapper_getops_t)
            _citrus_find_getops(cm->cm_module, module, "mapper");
        if (!getops) {
                ret = EOPNOTSUPP;
                goto err;
        }
        cm->cm_ops = malloc(sizeof(*cm->cm_ops));
        if (!cm->cm_ops) {
                ret = errno;
                goto err;
        }
        ret = (*getops)(cm->cm_ops);
        if (ret)
                goto err;

        if (!cm->cm_ops->mo_init ||
            !cm->cm_ops->mo_uninit ||
            !cm->cm_ops->mo_convert ||
            !cm->cm_ops->mo_init_state) {
                ret = EINVAL;
                goto err;
        }

        /* allocate traits structure */
        cm->cm_traits = malloc(sizeof(*cm->cm_traits));
        if (cm->cm_traits == NULL) {
                ret = errno;
                goto err;
        }
        /* initialize the mapper */
        ret = (*cm->cm_ops->mo_init)(ma, cm, ma->ma_dir,
            (const void *)variable, strlen(variable) + 1,
            cm->cm_traits, sizeof(*cm->cm_traits));
        if (ret)
                goto err;

        *rcm = cm;

        return (0);

err:
        mapper_close(cm);
        return (ret);
}

/*
 * _citrus_mapper_open_direct:
 *      open a mapper.
 */
int
_citrus_mapper_open_direct(struct _citrus_mapper_area *__restrict ma,
    struct _citrus_mapper * __restrict * __restrict rcm,
    const char * __restrict module, const char * __restrict variable)
{

        return (mapper_open(ma, rcm, module, variable));
}

/*
 * hash_func
 */
static __inline int
hash_func(const char *key)
{

        return (_string_hash_func(key, CM_HASH_SIZE));
}

/*
 * match_func
 */
static __inline int
match_func(struct _citrus_mapper *cm, const char *key)
{

        return (strcmp(cm->cm_key, key));
}

/*
 * _citrus_mapper_open:
 *      open a mapper with looking up "mapper.dir".
 */
int
_citrus_mapper_open(struct _citrus_mapper_area *__restrict ma,
    struct _citrus_mapper * __restrict * __restrict rcm,
    const char * __restrict mapname)
{
        struct _citrus_mapper *cm;
        char linebuf[PATH_MAX];
        const char *module, *variable;
        int hashval, ret;

        variable = NULL;

        WLOCK(&cm_lock);

        /* search in the cache */
        hashval = hash_func(mapname);
        _CITRUS_HASH_SEARCH(&ma->ma_cache, cm, cm_entry, match_func, mapname,
            hashval);
        if (cm) {
                /* found */
                cm->cm_refcount++;
                *rcm = cm;
                ret = 0;
                goto quit;
        }

        /* search mapper entry */
        ret = lookup_mapper_entry(ma->ma_dir, mapname, linebuf,
            (size_t)PATH_MAX, &module, &variable);
        if (ret)
                goto quit;

        /* open mapper */
        UNLOCK(&cm_lock);
        ret = mapper_open(ma, &cm, module, variable);
        WLOCK(&cm_lock);
        if (ret)
                goto quit;
        cm->cm_key = strdup(mapname);
        if (cm->cm_key == NULL) {
                ret = errno;
                _mapper_close(cm);
                goto quit;      
        }

        /* insert to the cache */
        cm->cm_refcount = 1;
        _CITRUS_HASH_INSERT(&ma->ma_cache, cm, cm_entry, hashval);

        *rcm = cm;
        ret = 0;
quit:
        UNLOCK(&cm_lock);

        return (ret);
}

/*
 * _citrus_mapper_close:
 *      close the specified mapper.
 */
void
_citrus_mapper_close(struct _citrus_mapper *cm)
{

        if (cm) {
                WLOCK(&cm_lock);
                if (cm->cm_refcount == REFCOUNT_PERSISTENT)
                        goto quit;
                if (cm->cm_refcount > 0) {
                        if (--cm->cm_refcount > 0)
                                goto quit;
                        _CITRUS_HASH_REMOVE(cm, cm_entry);
                        free(cm->cm_key);
                }
                UNLOCK(&cm_lock);
                mapper_close(cm);
                return;
quit:
                UNLOCK(&cm_lock);
        }
}

/*
 * _citrus_mapper_set_persistent:
 *      set persistent count.
 */
void
_citrus_mapper_set_persistent(struct _citrus_mapper * __restrict cm)
{

        WLOCK(&cm_lock);
        cm->cm_refcount = REFCOUNT_PERSISTENT;
        UNLOCK(&cm_lock);
}