source: mainline/uspace/srv/logger/namespace.c@ 01b8c2e4

/*
 * Copyright (c) 2012 Vojtech Horky
 * 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 logger
 * @{
 */
#include <assert.h>
#include <malloc.h>
#include <str.h>
#include <stdio.h>
#include "logger.h"

/** @file
 * Logging namespaces.
 */

struct logging_namespace {
        fibril_mutex_t guard;
        size_t writers_count;
        fibril_condvar_t reader_appeared_cv;
        bool has_reader;
        const char *name;
        link_t link;
        prodcons_t messages;
};

static FIBRIL_MUTEX_INITIALIZE(namespace_list_guard);
static LIST_INITIALIZE(namespace_list);

log_message_t *message_create(const char *name, log_level_t level)
{
        log_message_t *message = malloc(sizeof(log_message_t));
        if (message == NULL)
                return NULL;

        message->message = str_dup(name);
        if (message->message == NULL) {
                free(message);
                return NULL;
        }

        message->level = level;
        link_initialize(&message->link);

        return message;
}

void message_destroy(log_message_t *message)
{
        assert(message);
        free(message->message);
        free(message);
}

static logging_namespace_t *namespace_find_no_lock(const char *name)
{
        list_foreach(namespace_list, it) {
                logging_namespace_t *namespace = list_get_instance(it, logging_namespace_t, link);
                if (str_cmp(namespace->name, name) == 0) {
                        return namespace;
                }
        }

        return NULL;
}

static logging_namespace_t *namespace_create_no_lock(const char *name)
{
        logging_namespace_t *existing = namespace_find_no_lock(name);
        if (existing != NULL) {
                return NULL;
        }

        logging_namespace_t *namespace = malloc(sizeof(logging_namespace_t));
        if (namespace == NULL) {
                return NULL;
        }

        namespace->name = str_dup(name);
        if (namespace->name == NULL) {
                free(namespace);
                return NULL;
        }

        fibril_mutex_initialize(&namespace->guard);
        prodcons_initialize(&namespace->messages);
        namespace->has_reader = false;
        namespace->writers_count = 0;
        link_initialize(&namespace->link);

        list_append(&namespace->link, &namespace_list);

        return namespace;
}


logging_namespace_t *namespace_create(const char *name)
{
        fibril_mutex_lock(&namespace_list_guard);
        logging_namespace_t *result = namespace_create_no_lock(name);
        fibril_mutex_unlock(&namespace_list_guard);
        return result;
}

const char *namespace_get_name(logging_namespace_t *namespace)
{
        assert(namespace);
        return namespace->name;
}

static void namespace_destroy_careful(logging_namespace_t *namespace)
{
        assert(namespace);
        fibril_mutex_lock(&namespace_list_guard);

        fibril_mutex_lock(&namespace->guard);
        if (namespace->has_reader || (namespace->writers_count > 0)) {
                fibril_mutex_unlock(&namespace->guard);
                fibril_mutex_unlock(&namespace_list_guard);
                return;
        }

        list_remove(&namespace->link);

        fibril_mutex_unlock(&namespace->guard);
        fibril_mutex_unlock(&namespace_list_guard);

        // TODO - destroy pending messages
        free(namespace->name);
        free(namespace);
}

void namespace_destroy(logging_namespace_t *namespace)
{
        namespace_destroy_careful(namespace);
}

logging_namespace_t *namespace_reader_attach(const char *name)
{
        logging_namespace_t *namespace = NULL;

        fibril_mutex_lock(&namespace_list_guard);

        namespace = namespace_find_no_lock(name);

        if (namespace != NULL) {
                fibril_mutex_lock(&namespace->guard);
                namespace->has_reader = true;
                fibril_condvar_broadcast(&namespace->reader_appeared_cv);
                fibril_mutex_unlock(&namespace->guard);
        }

        fibril_mutex_unlock(&namespace_list_guard);

        return namespace;
}

logging_namespace_t *namespace_writer_attach(const char *name)
{
        logging_namespace_t *namespace = NULL;

        fibril_mutex_lock(&namespace_list_guard);

        namespace = namespace_find_no_lock(name);

        if (namespace == NULL) {
                namespace = namespace_create_no_lock(name);
        }

        fibril_mutex_lock(&namespace->guard);
        namespace->writers_count++;
        fibril_mutex_unlock(&namespace->guard);

        fibril_mutex_unlock(&namespace_list_guard);

        return namespace;
}

void namespace_reader_detach(logging_namespace_t *namespace)
{
        fibril_mutex_lock(&namespace->guard);
        namespace->has_reader = false;
        fibril_condvar_broadcast(&namespace->reader_appeared_cv);
        fibril_mutex_unlock(&namespace->guard);

        namespace_destroy_careful(namespace);
}

void namespace_writer_detach(logging_namespace_t *namespace)
{
        fibril_mutex_lock(&namespace->guard);
        assert(namespace->writers_count > 0);
        namespace->writers_count--;
        fibril_mutex_unlock(&namespace->guard);

        namespace_destroy_careful(namespace);
}

bool namespace_has_reader(logging_namespace_t *namespace)
{
        fibril_mutex_lock(&namespace->guard);
        bool has_reader = namespace->has_reader;
        fibril_mutex_unlock(&namespace->guard);
        return has_reader;
}

void namespace_wait_for_reader_change(logging_namespace_t *namespace, bool *has_reader_now)
{
        fibril_mutex_lock(&namespace->guard);
        bool had_reader = namespace->has_reader;
        while (had_reader == namespace->has_reader) {
                fibril_condvar_wait(&namespace->reader_appeared_cv, &namespace->guard);
        }
        *has_reader_now = namespace->has_reader;
        fibril_mutex_unlock(&namespace->guard);
}


void namespace_add_message(logging_namespace_t *namespace, const char *message, log_level_t level)
{
        if (level <= DEFAULT_LOGGING_LEVEL) {
                printf("[%s %d]: %s\n", namespace->name, level, message);
        }

        fibril_mutex_lock(&namespace->guard);
        if (namespace->has_reader) {
                log_message_t *msg = message_create(message, level);
                if (msg != NULL) {
                        prodcons_produce(&namespace->messages, &msg->link);
                }
        }
        fibril_mutex_unlock(&namespace->guard);
}

log_message_t *namespace_get_next_message(logging_namespace_t *namespace)
{
        link_t *message = prodcons_consume(&namespace->messages);

        return list_get_instance(message, log_message_t, link);
}


/**
 * @}
 */