msg_bus.h
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1 /*
2  * Copyright (C) 2020 ML!PA Consulting GmbH
3  *
4  * This file is subject to the terms and conditions of the GNU Lesser
5  * General Public License v2.1. See the file LICENSE in the top level
6  * directory for more details.
7  */
8 
38 #ifndef MSG_BUS_H
39 #define MSG_BUS_H
40 
41 #include <assert.h>
42 #include <stdint.h>
43 
44 #include "list.h"
45 #include "msg.h"
46 
47 #ifdef __cplusplus
48 extern "C" {
49 #endif
50 
54 typedef struct {
56  uint16_t id;
57 } msg_bus_t;
58 
63 typedef struct {
65  uint32_t event_mask;
68 
73 #define MSB_BUS_PID_FLAG (1U << ((8 * sizeof(kernel_pid_t)) - 1))
74 
86 
100 static inline uint16_t msg_bus_get_type(const msg_t *msg)
101 {
102  if (msg->sender_pid & MSB_BUS_PID_FLAG) {
103  return msg->type & 0x1F;
104  }
105  else {
106  return msg->type;
107  }
108 }
109 
121 static inline kernel_pid_t msg_bus_get_sender_pid(const msg_t *msg)
122 {
123  return msg->sender_pid & ~MSB_BUS_PID_FLAG;
124 }
125 
141 static inline bool msg_is_from_bus(const msg_bus_t *bus, const msg_t *msg)
142 {
143  if (bus != NULL && (bus->id != (msg->type >> 5))) {
144  return false;
145  }
146 
147  return msg->sender_pid & MSB_BUS_PID_FLAG;
148 }
149 
165 
177 
190 
199 static inline void msg_bus_subscribe(msg_bus_entry_t *entry, uint8_t type)
200 {
201  assert(type < 32);
202  entry->event_mask |= (1UL << type);
203 }
204 
213 static inline void msg_bus_unsubscribe(msg_bus_entry_t *entry, uint8_t type)
214 {
215  assert(type < 32);
216  entry->event_mask &= ~(1UL << type);
217 }
218 
236 
251 static inline int msg_bus_post(msg_bus_t *bus, uint8_t type, const void *arg)
252 {
253  assert(type < 32);
254 
255  msg_t m = {
256  .type = type | ((bus->id) << 5),
257  .content.ptr = (void *)arg,
258  };
259 
260  return msg_send_bus(&m, bus);
261 }
262 
263 #ifdef __cplusplus
264 }
265 #endif
266 
267 #endif /* MSG_BUS_H */
POSIX.1-2008 compliant version of the assert macro.
#define assert(cond)
abort the program if assertion is false
Definition: assert.h:113
int16_t kernel_pid_t
Unique process identifier.
Definition: sched.h:139
Intrusive linked list.
msg_bus_entry_t * msg_bus_get_entry(msg_bus_t *bus)
Get the message bus entry for the current thread.
void msg_bus_init(msg_bus_t *bus)
Initialize a message bus.
static uint16_t msg_bus_get_type(const msg_t *msg)
Get the message type of a message bus message.
Definition: msg_bus.h:100
static int msg_bus_post(msg_bus_t *bus, uint8_t type, const void *arg)
Post a message to a bus.
Definition: msg_bus.h:251
static void msg_bus_unsubscribe(msg_bus_entry_t *entry, uint8_t type)
Unsubscribe from an event on the message bus.
Definition: msg_bus.h:213
void msg_bus_attach(msg_bus_t *bus, msg_bus_entry_t *entry)
Attach a thread to a message bus.
static void msg_bus_subscribe(msg_bus_entry_t *entry, uint8_t type)
Subscribe to an event on the message bus.
Definition: msg_bus.h:199
static bool msg_is_from_bus(const msg_bus_t *bus, const msg_t *msg)
Check if a message originates from a bus.
Definition: msg_bus.h:141
static kernel_pid_t msg_bus_get_sender_pid(const msg_t *msg)
Get the sender PID of a message bus message.
Definition: msg_bus.h:121
#define MSB_BUS_PID_FLAG
Flag set on sender_pid of msg_t that indicates that the message was sent over a bus.
Definition: msg_bus.h:73
int msg_send_bus(msg_t *m, msg_bus_t *bus)
Post a pre-assembled message to a bus.
void msg_bus_detach(msg_bus_t *bus, msg_bus_entry_t *entry)
Remove a thread from a message bus.
List node structure.
Definition: list.h:40
Message bus subscriber entry.
Definition: msg_bus.h:63
kernel_pid_t pid
Subscriber PID.
Definition: msg_bus.h:66
uint32_t event_mask
Bitmask of event classes.
Definition: msg_bus.h:65
list_node_t next
next subscriber
Definition: msg_bus.h:64
A message bus is just a list of subscribers.
Definition: msg_bus.h:54
list_node_t subs
List of subscribers to the bus.
Definition: msg_bus.h:55
uint16_t id
Message Bus ID.
Definition: msg_bus.h:56
Describes a message object which can be sent between threads.
Definition: msg.h:196
uint16_t type
Type field.
Definition: msg.h:199
kernel_pid_t sender_pid
PID of sending thread.
Definition: msg.h:197
Definitions for parsing and composition of DNS messages.