source: mainline/uspace/srv/fs/udf/udf_idx.c

/*
 * Copyright (c) 2012 Julia Medvedeva
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * - 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.
 * - The name of the author may not be used to endorse or promote products
 *   derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 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.
 */

/** @addtogroup udf
 * @{
 */
/**
 * @file udf_idx.c
 * @brief Very simple UDF hashtable for nodes
 */

#include <errno.h>
#include <str.h>
#include <assert.h>
#include <fibril_synch.h>
#include <stdlib.h>
#include <adt/hash_table.h>
#include <adt/hash.h>
#include <adt/list.h>
#include <stdbool.h>
#include "udf_idx.h"
#include "udf.h"

static FIBRIL_MUTEX_INITIALIZE(udf_idx_lock);

static hash_table_t udf_idx;

typedef struct {
        service_id_t service_id;
        fs_index_t index;
} udf_ht_key_t;

static size_t udf_idx_hash(const ht_link_t *item)
{
        udf_node_t *node = hash_table_get_inst(item, udf_node_t, link);
        return hash_combine(node->instance->service_id, node->index);
}

static size_t udf_idx_key_hash(const void *k)
{
        const udf_ht_key_t *key = k;
        return hash_combine(key->service_id, key->index);
}

static bool udf_idx_key_equal(const void *k, size_t hash, const ht_link_t *item)
{
        const udf_ht_key_t *key = k;
        udf_node_t *node = hash_table_get_inst(item, udf_node_t, link);

        return (key->service_id == node->instance->service_id) &&
            (key->index == node->index);
}

static const hash_table_ops_t udf_idx_ops = {
        .hash = udf_idx_hash,
        .key_hash = udf_idx_key_hash,
        .key_equal = udf_idx_key_equal,
        .equal = NULL,
        .remove_callback = NULL
};

/** Initialization of hash table
 *
 * @return EOK on success or an error code.
 *
 */
errno_t udf_idx_init(void)
{
        if (!hash_table_create(&udf_idx, 0, 0, &udf_idx_ops))
                return ENOMEM;

        return EOK;
}

/** Delete hash table
 *
 * @return EOK on success or an error code.
 *
 */
errno_t udf_idx_fini(void)
{
        hash_table_destroy(&udf_idx);
        return EOK;
}

/** Get node from hash table
 *
 * @param udfn     Returned value - UDF node
 * @param instance UDF instance
 * @param index    Absolute position of ICB (sector)
 *
 * @return EOK on success or an error code.
 *
 */
errno_t udf_idx_get(udf_node_t **udfn, udf_instance_t *instance, fs_index_t index)
{
        fibril_mutex_lock(&udf_idx_lock);

        udf_ht_key_t key = {
                .service_id = instance->service_id,
                .index = index
        };

        ht_link_t *already_open = hash_table_find(&udf_idx, &key);
        if (already_open) {
                udf_node_t *node = hash_table_get_inst(already_open,
                    udf_node_t, link);
                node->ref_cnt++;

                *udfn = node;

                fibril_mutex_unlock(&udf_idx_lock);
                return EOK;
        }

        fibril_mutex_unlock(&udf_idx_lock);
        return ENOENT;
}

/** Create new node in hash table
 *
 * @param udfn     Returned value - new UDF node
 * @param instance UDF instance
 * @param index    Absolute position of ICB (sector)
 *
 * @return EOK on success or an error code.
 *
 */
errno_t udf_idx_add(udf_node_t **udfn, udf_instance_t *instance, fs_index_t index)
{
        fibril_mutex_lock(&udf_idx_lock);

        udf_node_t *udf_node = malloc(sizeof(udf_node_t));
        if (udf_node == NULL) {
                fibril_mutex_unlock(&udf_idx_lock);
                return ENOMEM;
        }

        fs_node_t *fs_node = malloc(sizeof(fs_node_t));
        if (fs_node == NULL) {
                free(udf_node);
                fibril_mutex_unlock(&udf_idx_lock);
                return ENOMEM;
        }

        fs_node_initialize(fs_node);

        udf_node->index = index;
        udf_node->instance = instance;
        udf_node->ref_cnt = 1;
        udf_node->link_cnt = 0;
        udf_node->fs_node = fs_node;
        udf_node->data = NULL;
        udf_node->allocators = NULL;

        fibril_mutex_initialize(&udf_node->lock);
        fs_node->data = udf_node;

        hash_table_insert(&udf_idx, &udf_node->link);
        instance->open_nodes_count++;

        *udfn = udf_node;

        fibril_mutex_unlock(&udf_idx_lock);
        return EOK;
}

/** Delete node from hash table
 *
 * @param node UDF node
 *
 * @return EOK on success or an error code.
 *
 */
errno_t udf_idx_del(udf_node_t *node)
{
        assert(node->ref_cnt == 0);

        fibril_mutex_lock(&udf_idx_lock);

        hash_table_remove_item(&udf_idx, &node->link);

        assert(node->instance->open_nodes_count > 0);
        node->instance->open_nodes_count--;

        free(node->fs_node);
        free(node);

        fibril_mutex_unlock(&udf_idx_lock);
        return EOK;
}

/**
 * @}
 */