stasis_message.c

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/*
 * Asterisk -- An open source telephony toolkit.
 *
 * Copyright (C) 2013, Digium, Inc.
 *
 * David M. Lee, II <dlee@digium.com>
 *
 * See http://www.asterisk.org for more information about
 * the Asterisk project. Please do not directly contact
 * any of the maintainers of this project for assistance;
 * the project provides a web site, mailing lists and IRC
 * channels for your use.
 *
 * This program is free software, distributed under the terms of
 * the GNU General Public License Version 2. See the LICENSE file
 * at the top of the source tree.
 */
 
/*! \file
 *
 * \brief Stasis Message API.
 *
 * \author David M. Lee, II <dlee@digium.com>
 */
 
/*** MODULEINFO
    <support_level>core</support_level>
 ***/
 
#include "asterisk.h"
 
#include "asterisk/astobj2.h"
#include "asterisk/stasis.h"
#include "asterisk/utils.h"
#include "asterisk/hashtab.h"
 
/*! \internal */
struct stasis_message_type {
    struct stasis_message_vtable *vtable;
    char *name;
    unsigned int hash;
    int id;
    enum stasis_subscription_message_formatters available_formatters;
};
 
static struct stasis_message_vtable null_vtable = {};
static int message_type_id;
 
static void message_type_dtor(void *obj)
{
    struct stasis_message_type *type = obj;
    ast_free(type->name);
    type->name = NULL;
}
 
enum stasis_message_type_result stasis_message_type_create(const char *name,
    struct stasis_message_vtable *vtable,
    struct stasis_message_type **result)
{
    struct stasis_message_type *type;
 
    /* Check for declination */
    if (name && stasis_message_type_declined(name)) {
        return STASIS_MESSAGE_TYPE_DECLINED;
    }
 
    type = ao2_t_alloc_options(sizeof(*type), message_type_dtor,
        AO2_ALLOC_OPT_LOCK_NOLOCK, name ?: "");
    if (!type) {
        return STASIS_MESSAGE_TYPE_ERROR;
    }
    if (!vtable) {
        /* Null object pattern, FTW! */
        vtable = &null_vtable;
    }
 
    type->name = ast_strdup(name);
    if (!type->name) {
        ao2_cleanup(type);
        return STASIS_MESSAGE_TYPE_ERROR;
    }
    type->hash = ast_hashtab_hash_string(name);
    type->vtable = vtable;
    if (vtable->to_json) {
        type->available_formatters |= STASIS_SUBSCRIPTION_FORMATTER_JSON;
    }
    if (vtable->to_ami) {
        type->available_formatters |= STASIS_SUBSCRIPTION_FORMATTER_AMI;
    }
    if (vtable->to_event) {
        type->available_formatters |= STASIS_SUBSCRIPTION_FORMATTER_EVENT;
    }
    type->id = ast_atomic_fetchadd_int(&message_type_id, +1);
    *result = type;
 
    return STASIS_MESSAGE_TYPE_SUCCESS;
}
 
const char *stasis_message_type_name(const struct stasis_message_type *type)
{
    return type->name;
}
 
unsigned int stasis_message_type_hash(const struct stasis_message_type *type)
{
    return type->hash;
}
 
int stasis_message_type_id(const struct stasis_message_type *type)
{
    return type->id;
}
 
enum stasis_subscription_message_formatters stasis_message_type_available_formatters(
    const struct stasis_message_type *type)
{
    return type->available_formatters;
}
 
/*! \internal */
struct stasis_message {
    /*! Time the message was created */
    struct timeval timestamp;
    /*! Type of the message */
    struct stasis_message_type *type;
    /*! Where this message originated.  NULL if aggregate message. */
    const struct ast_eid *eid_ptr;
    /*! Message content */
    void *data;
    /*! Where this message originated. */
    struct ast_eid eid;
};
 
static void stasis_message_dtor(void *obj)
{
    struct stasis_message *message = obj;
    ao2_cleanup(message->data);
}
 
struct stasis_message *stasis_message_create_full(struct stasis_message_type *type, void *data, const struct ast_eid *eid)
{
    struct stasis_message *message;
 
    if (type == NULL || data == NULL) {
        return NULL;
    }
 
    message = ao2_t_alloc_options(sizeof(*message), stasis_message_dtor,
        AO2_ALLOC_OPT_LOCK_NOLOCK, type->name);
    if (message == NULL) {
        return NULL;
    }
 
    message->timestamp = ast_tvnow();
    /*
     * XXX Normal ao2 ref counting rules says we should increment the message
     * type ref here and decrement it in stasis_message_dtor().  However, the
     * stasis message could be cached and legitimately cause the type ref count
     * to hit the excessive ref count assertion.  Since the message type
     * practically has to be a global object anyway, we can get away with not
     * holding a ref in the stasis message.
     */
    message->type = type;
    ao2_ref(data, +1);
    message->data = data;
    if (eid) {
        message->eid_ptr = &message->eid;
        message->eid = *eid;
    }
 
    return message;
}
 
struct stasis_message *stasis_message_create(struct stasis_message_type *type, void *data)
{
    return stasis_message_create_full(type, data, &ast_eid_default);
}
 
const struct ast_eid *stasis_message_eid(const struct stasis_message *msg)
{
    if (msg == NULL) {
        return NULL;
    }
    return msg->eid_ptr;
}
 
struct stasis_message_type *stasis_message_type(const struct stasis_message *msg)
{
    if (msg == NULL) {
        return NULL;
    }
    return msg->type;
}
 
void *stasis_message_data(const struct stasis_message *msg)
{
    if (msg == NULL) {
        return NULL;
    }
    return msg->data;
}
 
const struct timeval *stasis_message_timestamp(const struct stasis_message *msg)
{
    if (msg == NULL) {
        return NULL;
    }
    return &msg->timestamp;
}
 
#define INVOKE_VIRTUAL(fn, ...)                 \
    ({                                          \
        if (!msg) {                             \
            return NULL;                        \
        }                                       \
        ast_assert(msg->type != NULL);          \
        ast_assert(msg->type->vtable != NULL);  \
        if (!msg->type->vtable->fn) {           \
            return NULL;                        \
        }                                       \
        msg->type->vtable->fn(__VA_ARGS__);     \
    })
 
struct ast_manager_event_blob *stasis_message_to_ami(struct stasis_message *msg)
{
    return INVOKE_VIRTUAL(to_ami, msg);
}
 
struct ast_json *stasis_message_to_json(
    struct stasis_message *msg,
    struct stasis_message_sanitizer *sanitize)
{
    return INVOKE_VIRTUAL(to_json, msg, sanitize);
}
 
struct ast_event *stasis_message_to_event(struct stasis_message *msg)
{
    return INVOKE_VIRTUAL(to_event, msg);
}
 
#define HAS_VIRTUAL(fn, msg)                    \
    ({                                          \
        if (!msg) {                             \
            return 0;                           \
        }                                       \
        ast_assert(msg->type != NULL);          \
        ast_assert(msg->type->vtable != NULL);  \
        !!msg->type->vtable->fn;                \
    })
 
int stasis_message_can_be_ami(struct stasis_message *msg)
{
    return HAS_VIRTUAL(to_ami, msg);
}