From 7858930d38c85765405de4831117cda24134bde6 Mon Sep 17 00:00:00 2001
Message-Id: <7858930d38c85765405de4831117cda24134bde6.1715505091.git.mdw@distorted.org.uk>
From: Mark Wooding <mdw@chiark.greenend.org.uk>
Date: Sun, 30 Sep 2007 14:56:11 +0100
Subject: [PATCH] disobedience now detects disconnection within ~1s
Organization: Straylight/Edgeware

From: rjk@greenend.org.uk <>

---
 disobedience/disobedience.c | 27 +++++++++++++++++++++++++++
 doc/disorder_protocol.5.in  |  5 +++++
 lib/eclient.c               |  7 +++++++
 lib/eclient.h               |  4 ++++
 server/server.c             |  8 ++++++++
 5 files changed, 51 insertions(+)

diff --git a/disobedience/disobedience.c b/disobedience/disobedience.c
index b45b007..3c3fae6 100644
--- a/disobedience/disobedience.c
+++ b/disobedience/disobedience.c
@@ -59,6 +59,9 @@ int volume_l, volume_r;                 /* volume */
 double goesupto = 10;                   /* volume upper bound */
 int choosealpha;                        /* break up choose by letter */
 
+/** @brief True if a NOP is in flight */
+static int nop_in_flight;
+
 static const disorder_eclient_log_callbacks gdisorder_log_callbacks = {
   log_connected,
   log_completed,
@@ -375,6 +378,24 @@ static gboolean heartbeat(gpointer attribute((unused)) data) {
   return TRUE;
 }
 
+/** @brief Called when a NOP completes */
+static void nop_completed(void attribute((unused)) *v) {
+  nop_in_flight = 0;
+}
+
+/** @brief Called from time to time to arrange for a NOP to be sent
+ *
+ * At most one NOP remains in flight at any moment.  If the client is not
+ * currently connected then no NOP is sent.
+ */
+static gboolean maybe_send_nop(gpointer attribute((unused)) data) {
+  if(!nop_in_flight && disorder_eclient_connected(client)) {
+    nop_in_flight = 1;
+    disorder_eclient_nop(client, nop_completed, 0);
+  }
+  return TRUE;                          /* keep call me please */
+}
+
 /* main -------------------------------------------------------------------- */
 
 static const struct option options[] = {
@@ -463,6 +484,12 @@ int main(int argc, char **argv) {
   gtk_widget_show_all(toplevel);
   /* set initial control button visibility/usability */
   control_update();
+  /* issue a NOP every so often */
+  g_timeout_add_full(G_PRIORITY_LOW,
+                     1000/*interval, ms*/,
+                     maybe_send_nop,
+                     0/*data*/,
+                     0/*notify*/);
   D(("enter main loop"));
   MTAG("misc");
   g_main_loop_run(mainloop);
diff --git a/doc/disorder_protocol.5.in b/doc/disorder_protocol.5.in
index f3af468..d3ad537 100644
--- a/doc/disorder_protocol.5.in
+++ b/doc/disorder_protocol.5.in
@@ -109,6 +109,11 @@ the queue.  If \fITARGET\fR is listed in the ID list then the tracks are moved
 to just after the first non-listed track before it, or to the head if there is
 no such track.
 .TP
+.B nop
+Do nothing.  Used by
+.BR disobedience (1)
+as a keepalive measure.
+.TP
 .B part \fITRACK\fR \fICONTEXT\fI \fIPART\fR
 Get a track name part.  Returns an empty string if a name part cannot be
 constructed.
diff --git a/lib/eclient.c b/lib/eclient.c
index 201da38..e98d152 100644
--- a/lib/eclient.c
+++ b/lib/eclient.c
@@ -1136,6 +1136,13 @@ int disorder_eclient_search(disorder_eclient *c,
                 "search", terms, (char *)0);
 }
 
+int disorder_eclient_nop(disorder_eclient *c,
+                         disorder_eclient_no_response *completed,
+                         void *v) {
+  return simple(c, no_response_opcallback, (void (*)())completed, v, 
+                "nop", (char *)0);
+}
+
 /* Log clients ***************************************************************/
 
 /** @brief Monitor the server log
diff --git a/lib/eclient.h b/lib/eclient.h
index d1e4e97..d898ca8 100644
--- a/lib/eclient.h
+++ b/lib/eclient.h
@@ -292,6 +292,10 @@ int disorder_eclient_search(disorder_eclient *c,
                             const char *terms,
                             void *v);
 
+int disorder_eclient_nop(disorder_eclient *c,
+                         disorder_eclient_no_response *completed,
+                         void *v);
+
 #endif
 
 /*
diff --git a/server/server.c b/server/server.c
index 5837e38..cb7714e 100644
--- a/server/server.c
+++ b/server/server.c
@@ -900,6 +900,13 @@ static int c_get_global(struct conn *c,
   return 1;
 }
 
+static int c_nop(struct conn *c,
+		 char attribute((unused)) **vec,
+		 int attribute((unused)) nvec) {
+  sink_printf(ev_writer_sink(c->w), "250 Quack\n");
+  return 1;
+}
+
 #define C_AUTH		0001		/* must be authenticated */
 #define C_TRUSTED	0002		/* must be trusted user */
 
@@ -923,6 +930,7 @@ static const struct command {
   { "log",            0, 0,       c_log,            C_AUTH },
   { "move",           2, 2,       c_move,           C_AUTH },
   { "moveafter",      1, INT_MAX, c_moveafter,      C_AUTH },
+  { "nop",            0, 0,       c_nop,            C_AUTH },
   { "part",           3, 3,       c_part,           C_AUTH },
   { "pause",          0, 0,       c_pause,          C_AUTH },
   { "play",           1, 1,       c_play,           C_AUTH },
-- 
[mdw]