[mpd] add binarylimit command (unused still)

Maintain the binary limit, and use the default MPD uses too.  This comes
in handy when we are going to send binary responses such as in PR #1780

Signed-off-by: Fabian Groffen <grobian@gentoo.org>

src/mpd.c

@@ -65,6 +65,8 @@ enum mpd_type {
 
 #define MPD_ALL_IDLE_LISTENER_EVENTS (LISTENER_PLAYER | LISTENER_QUEUE | LISTENER_VOLUME | LISTENER_SPEAKER | LISTENER_OPTIONS | LISTENER_DATABASE | LISTENER_UPDATE | LISTENER_STORED_PLAYLIST | LISTENER_RATING)
 #define MPD_RATING_FACTOR 10.0
+#define MPD_BINARY_SIZE 8192  /* MPD MAX_BINARY_SIZE */
+#define MPD_BINARY_SIZE_MIN 64  /* min size from MPD ClientCommands.cxx */
 
 static pthread_t tid_mpd;
 
@@ -229,6 +231,9 @@ struct mpd_client_ctx
   // The events the client is waiting for (set by the idle command)
   short idle_events;
 
+  // The current binary limit size
+  unsigned int binarylimit;
+
   // The output buffer for the client (used to send data to the client)
   struct evbuffer *evbuffer;
 
@@ -3589,6 +3594,30 @@ mpd_command_password(struct evbuffer *evbuf, int argc, char **argv, char **errms
   return ACK_ERROR_PASSWORD;
 }
 
+static int
+mpd_command_binarylimit(struct evbuffer *evbuf, int argc, char **argv, char **errmsg, struct mpd_client_ctx *ctx)
+{
+  unsigned int size;
+
+  if (safe_atou32(argv[1], &size) < 0)
+    {
+      DPRINTF(E_DBG, L_MPD,
+      	      "Argument %s to binarylimit is not a number\n",
+      	      argv[1]);
+      return ACK_ERROR_ARG;
+    }
+
+  if (size < MPD_BINARY_SIZE_MIN)
+    {
+      *errmsg = safe_asprintf("Value too small");
+      return ACK_ERROR_ARG;
+    }
+
+  ctx->binarylimit = size;
+
+  return 0;
+}
+
 /*
  * Callback function for the 'player_speaker_enumerate' function.
  * Expect a struct output_get_param as argument and allocates a struct output if
@@ -4227,6 +4256,8 @@ static struct mpd_command mpd_handlers[] =
 //    { "kill",                       mpd_command_kill,                       -1 },
     { "password",                   mpd_command_password,                   -1 },
     { "ping",                       mpd_command_ignore,                     -1 },
+    { "binarylimit",                mpd_command_binarylimit,                 2 },
+    /* missing: tagtypes */
 
     // Audio output devices
     { "disableoutput",              mpd_command_disableoutput,               2 },
@@ -4571,6 +4602,8 @@ mpd_accept_conn_cb(struct evconnlistener *listener,
       client_ctx->authenticated = net_peer_address_is_trusted((union net_sockaddr *)address);
     }
 
+  client_ctx->binarylimit = MPD_BINARY_SIZE;
+
   client_ctx->next = mpd_clients;
   mpd_clients = client_ctx;