Don't assume that all callbacks are set.

If one of callbacks is not set, the application crashes.
This is the case when you update the library and the update adds more
callbacks, or when you simply don't want to receive some of the updates
(callbacks).
In any case, defining all callbacks shouldn't be mandatory.

1 files changed, 24 insertions, 4 deletions

diff --git a/core/Messenger.c b/core/Messenger.c
index 5a10c1da..bb581a45 100644
--- a/core/Messenger.c
+++ b/core/Messenger.c
@@ -355,33 +355,41 @@ static int set_friend_userstatus(int friendnumber, uint8_t * status, uint16_t le
 }
 
 static void (*friend_request)(uint8_t *, uint8_t *, uint16_t);
+static uint8_t friend_request_isset = 0;
 
 //set the function that will be executed when a friend request is received.
 void m_callback_friendrequest(void (*function)(uint8_t *, uint8_t *, uint16_t))
 {
     friend_request = function;
+    friend_request_isset = 1;
 }
 
 
 static void (*friend_message)(int, uint8_t *, uint16_t);
+static uint8_t friend_message_isset = 0;
 
 //set the function that will be executed when a message from a friend is received.
 void m_callback_friendmessage(void (*function)(int, uint8_t *, uint16_t))
 {
     friend_message = function;
+    friend_message_isset = 1;
 }
 
 
 static void (*friend_namechange)(int, uint8_t *, uint16_t);
+static uint8_t friend_namechange_isset = 0;
 void m_callback_namechange(void (*function)(int, uint8_t *, uint16_t))
 {
     friend_namechange = function;
+    friend_namechange_isset = 1;
 }
 
 static void (*friend_statuschange)(int, uint8_t *, uint16_t);
+static uint8_t friend_statuschange_isset = 0;
 void m_callback_userstatus(void (*function)(int, uint8_t *, uint16_t))
 {
     friend_statuschange = function;
+    friend_statuschange_isset = 1;
 }
 
 #define PORT 33445
@@ -458,7 +466,10 @@ static void doFriends()
                 switch(temp[0]) {
                     case PACKET_ID_NICKNAME: {
                         if (len != MAX_NAME_LENGTH + 1) break;
-                        friend_namechange(i, temp + 1, MAX_NAME_LENGTH); // todo: use the actual length
+                        if(friend_namechange_isset)
+                        {
+                            friend_namechange(i, temp + 1, MAX_NAME_LENGTH); // todo: use the actual length
+                        }
                         memcpy(friendlist[i].name, temp + 1, MAX_NAME_LENGTH);
                         friendlist[i].name[MAX_NAME_LENGTH - 1] = 0;//make sure the NULL terminator is present.
                         break;
@@ -466,13 +477,19 @@ static void doFriends()
                     case PACKET_ID_USERSTATUS: {
                         uint8_t *status = calloc(MIN(len - 1, MAX_USERSTATUS_LENGTH), 1);
                         memcpy(status, temp + 1, MIN(len - 1, MAX_USERSTATUS_LENGTH));
-                        friend_statuschange(i, status, MIN(len - 1, MAX_USERSTATUS_LENGTH));
+                        if(friend_statuschange_isset)
+                        {
+                            friend_statuschange(i, status, MIN(len - 1, MAX_USERSTATUS_LENGTH));
+                        }
                         set_friend_userstatus(i, status, MIN(len - 1, MAX_USERSTATUS_LENGTH));
                         free(status);
                         break;
                     }
                     case PACKET_ID_MESSAGE: {
-                        (*friend_message)(i, temp + 1, len - 1);
+                        if(friend_message_isset)
+                        {
+                            (*friend_message)(i, temp + 1, len - 1);
+                        }
                         break;
                     }
                 }
@@ -499,7 +516,10 @@ static void doFriendRequest()
     int len = handle_friendrequest(public_key, temp);
     if(len >= 0)
     {
-        (*friend_request)(public_key, temp, len);
+        if(friend_request_isset)
+        {
+            (*friend_request)(public_key, temp, len);
+        }
     }
 }