msg_bus.h

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/*
 * Copyright (C) 2020 ML!PA Consulting GmbH
 *
 * This file is subject to the terms and conditions of the GNU Lesser
 * General Public License v2.1. See the file LICENSE in the top level
 * directory for more details.
 */
 
#ifndef MSG_BUS_H
#define MSG_BUS_H
 
#include <assert.h>
#include <stdint.h>
 
#include "list.h"
#include "msg.h"
 
#ifdef __cplusplus
extern "C" {
#endif
 
typedef struct {
    list_node_t subs;       
    uint16_t id;            
} msg_bus_t;
 
typedef struct {
    list_node_t next;       
    uint32_t event_mask;    
    kernel_pid_t pid;       
} msg_bus_entry_t;
 
#define MSB_BUS_PID_FLAG    (1U << ((8 * sizeof(kernel_pid_t)) - 1))
 
void msg_bus_init(msg_bus_t *bus);
 
static inline uint16_t msg_bus_get_type(const msg_t *msg)
{
    if (msg->sender_pid & MSB_BUS_PID_FLAG) {
        return msg->type & 0x1F;
    } else {
        return msg->type;
    }
}
 
static inline kernel_pid_t msg_bus_get_sender_pid(const msg_t *msg)
{
    return msg->sender_pid & ~MSB_BUS_PID_FLAG;
}
 
static inline bool msg_is_from_bus(const msg_bus_t *bus, const msg_t *msg)
{
    if (bus != NULL && (bus->id != (msg->type >> 5))) {
        return false;
    }
 
    return msg->sender_pid & MSB_BUS_PID_FLAG;
}
 
void msg_bus_attach(msg_bus_t *bus, msg_bus_entry_t *entry);
 
void msg_bus_detach(msg_bus_t *bus, msg_bus_entry_t *entry);
 
msg_bus_entry_t *msg_bus_get_entry(msg_bus_t *bus);
 
static inline void msg_bus_subscribe(msg_bus_entry_t *entry, uint8_t type)
{
    assert(type < 32);
    entry->event_mask |= (1UL << type);
}
 
static inline void msg_bus_unsubscribe(msg_bus_entry_t *entry, uint8_t type)
{
    assert(type < 32);
    entry->event_mask &= ~(1UL << type);
}
 
int msg_send_bus(msg_t *m, msg_bus_t *bus);
 
static inline int msg_bus_post(msg_bus_t *bus, uint8_t type, const void *arg)
{
    assert(type < 32);
 
    msg_t m = {
        .type = type | ((bus->id) << 5),
        .content.ptr = (void *)arg,
    };
 
    return msg_send_bus(&m, bus);
}
 
#ifdef __cplusplus
}
#endif
 
#endif /* MSG_BUS_H */