RFC: remote.c incoming packet cleanups

[Michael Snyder]

Eli Zaretskii wrote:
>>Date: Thu, 23 Feb 2006 09:56:21 -0500
>>From: Daniel Jacobowitz <drow@false.org>
>>
>>The basic change is to convert getpkt from (char *buf, int len,
>>int forever) to (char **buf_p, int *len, int forever) and allocate
>>*buf_p with xmalloc, so that we can pass it to xrealloc.  All
>>the rest is cascading changes.
> 
> 
> This is fine with me, but you wrote this code in get_memory_packet_size:
> 
> 
>>@@ -436,6 +455,15 @@ get_memory_packet_size (struct memory_pa
>>     what_they_get = MAX_REMOTE_PACKET_SIZE;
>>   if (what_they_get < MIN_REMOTE_PACKET_SIZE)
>>     what_they_get = MIN_REMOTE_PACKET_SIZE;
>>+
>>+  /* Make sure there is room in the global buffer for this packet
>>+     (including its trailing NUL byte).  */
>>+  if (rs->buf_size < what_they_get + 1)
>>+    {
>>+      rs->buf_size = what_they_get + 1;
>>+      rs->buf = xrealloc (rs->buf, what_they_get + 1);
>>+    }
>>+
>>   return what_they_get;
>> }
> 
> 
> I wonder whether it would be better to expand by multiplying the
> previous size by 2, instead of just making enough room for the current
> packet.  The latter could cause bad memory fragmentation under some
> pathological patterns of packet size sequences.  (And in read_frame you
> indeed multiply by two when you realloc the buffer.)

Second that.  Realloc by one doesn't sit right.   ;-)