UltraGrid/src/module.h

/**
 * @file   module.h
 * @author Martin Pulec     <pulec@cesnet.cz>
 * @ingroup module
 */
/*
 * Copyright (c) 2013-2025 CESNET
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, is 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.
 *
 * 3. Neither the name of CESNET nor the names of its contributors may be
 *    used to endorse or promote products derived from this software without
 *    specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESSED 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 AUTHORS 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.
 */
/**
 * @file module.h
 *
 * @defgroup module Module infrastructure
 * @{
 *
 * ### Module registration
 * Example:
 * ```
 * struct state {
 *      struct module mod;
 *      ...
 * } s;
 * module_init_default(&s->mod);
 * s->mod.cls = MODULE_CLASS_<NAME>; // always needed
 * s->mod.priv_data = s;             // optional
 * module_register(&s->mod, s->parent);
 * ```
 */

#ifndef MODULE_H_
#define MODULE_H_

#include "messaging.h"
#include "utils/macros.h"

#include <pthread.h>

#ifdef __cplusplus
#include <cstdint>
#else
#include <stdint.h>
#endif

#ifdef __cplusplus
extern "C" {
#endif

enum module_class {
        MODULE_CLASS_NONE = 0,
        MODULE_CLASS_ROOT,
        MODULE_CLASS_PORT,
        MODULE_CLASS_COMPRESS,
        MODULE_CLASS_DATA,
        MODULE_CLASS_SENDER,
        MODULE_CLASS_RECEIVER,
        MODULE_CLASS_TX,
        MODULE_CLASS_AUDIO,
        MODULE_CLASS_CONTROL,
        MODULE_CLASS_CAPTURE,
        MODULE_CLASS_FILTER,
        MODULE_CLASS_DISPLAY,
        MODULE_CLASS_DECODER,
        MODULE_CLASS_EXPORTER,
        MODULE_CLASS_KEYCONTROL,
};

struct module;
struct module_priv_state;
struct simple_linked_list;

typedef void (*notify_t)(struct module *);

/**
 * @struct module
 * Only members cls, priv_data and msg_queue may be directly touched
 * by user. The others should be considered private.
 */
struct module {
        enum module_class cls;
        notify_t new_message; ///< if set, notifies module that new message is in queue, receiver lock is hold during the call
        void *priv_data; ///< optional; can be used to store state pointer for
                         ///< new_message() or to retreive the state from the
                         ///< module (control_socket)
        char name[128]; ///< optional name of the module. May be used for indexing.

        struct module_priv_state *module_priv; ///< set by module_register()
};

struct module_priv_state {
        uint32_t magic;
        struct module wrapper;
        pthread_mutex_t lock;
        int ref;  ///< reference count
        struct module_priv_state *parent;
        struct simple_linked_list *children; // module_priv_state

        pthread_mutex_t msg_queue_lock; // protects msg_queue
        struct simple_linked_list *msg_queue;

        struct simple_linked_list *msg_queue_children; ///< messages for children that were not delivered

        //uint32_t id;
};

void module_init_default(struct module *module_data);
/// module_register makes a private copy struct module so subsequent
/// changes in that structure won't affect the registered one
void module_register(struct module *module_data, struct module *parent);
void module_done(struct module *module_data);
const char *module_class_name(enum module_class cls);
void        append_message_path(char *buf, int buflen,
                                const enum module_class *modules);
bool module_get_path_str(struct module *mod, char *buf, size_t buflen);

#ifdef __cplusplus
class module_raii{
public:
        module_raii(enum module_class type, module *parent, void *priv){
                module_init_default(&mod);
                mod.priv_data = priv;
                mod.cls = type;
                module_register(&mod, parent);
        }

        ~module_raii(){
                module_done(&mod);
        }

        module *get(){ return &mod; }
private:
        module mod;
};
#endif

/**
 * @retval NULL if not found
 * @retval non-NULL pointer to the module
 */
struct module *get_module(struct module *root, const char *path);

/**
 * IMPORTANT: module given as parameter should be locked within the calling thread.
 *
 * @retval NULL if not found
 * @retval non-NULL pointer to the module
 */
struct module *get_matching_child(struct module *node, const char *path);

/**
 * Returns pointer to root module.
 *
 * @retval root module
 */
struct module *get_root_module(struct module *mod);

struct module *get_parent_module(struct module *node);

void dump_tree(struct module *root_node, int indent);
void dump_parents(struct module *node);

#ifdef __cplusplus
}
#endif

#endif
/**
 * @} // group module
 */