add '@' command to switch calls using line numbers

1. for a given UA, each call has a unique line number starting
   from 1

2. the list of calls is sorted in an arbitrary order, but the
   last list element indicates "current call"

3. the '@' command takes a numeric argument which is the
   line-number of the wanted call

3 files changed, 73 insertions, 25 deletions

diff --git a/src/call.c b/src/call.c
index 50910dc..e0fec6b 100644
--- a/src/call.c
+++ b/src/call.c
@@ -439,6 +439,22 @@ static void stream_error_handler(struct stream *strm, int err, void *arg)
 }
 
 
+static int assign_linenum(uint32_t *linenum, const struct list *lst)
+{
+	uint32_t num;
+
+	for (num=CALL_LINENUM_MIN; num<CALL_LINENUM_MAX; num++) {
+
+		if (!call_find_linenum(lst, num)) {
+			*linenum = num;
+			return 0;
+		}
+	}
+
+	return ENOENT;
+}
+
+
 /**
  * Allocate a new Call state object
  *
@@ -466,7 +482,6 @@ int call_alloc(struct call **callp, const struct config *cfg, struct list *lst,
 	struct call *call;
 	struct le *le;
 	enum vidmode vidmode = prm ? prm->vidmode : VIDMODE_OFF;
-	uint32_t wanted_linenum = 1;
 	bool use_video = true, got_offer = false;
 	int label = 0;
 	int err = 0;
@@ -597,27 +612,16 @@ int call_alloc(struct call **callp, const struct config *cfg, struct list *lst,
 		call_enable_rtp_timeout(call, cfg->avt.rtp_timeout*1000);
 	}
 
-	for (le = lst->head; le; le = le->next) {
-
-		const struct call *call0 = le->data;
-
-		if (call0->linenum == wanted_linenum) {
-			/* that linenum was busy, increment */
-			++wanted_linenum;
-			continue;
-		}
-		else if (call0->linenum > wanted_linenum) {
-			/* wanted linenum is free */
-			list_insert_before(lst, le, &call->le, call);
-			call->linenum = wanted_linenum;
-			break;
-		}
+	err = assign_linenum(&call->linenum, lst);
+	if (err) {
+		warning("call: could not assign linenumber\n");
+		goto out;
 	}
 
-	if (!call->le.list) {
-		list_append(lst, &call->le, call);
-		call->linenum = list_count(lst);
-	}
+	/* NOTE: The new call must always be added to the tail of list,
+	 *       which indicates the current call.
+	 */
+	list_append(lst, &call->le, call);
 
  out:
 	if (err)
@@ -1799,3 +1803,28 @@ uint32_t call_linenum(const struct call *call)
 {
 	return call ? call->linenum : 0;
 }
+
+
+struct call *call_find_linenum(const struct list *calls, uint32_t linenum)
+{
+	struct le *le;
+
+	for (le = list_head(calls); le; le = le->next) {
+		struct call *call = le->data;
+
+		if (linenum == call->linenum)
+			return call;
+	}
+
+	return NULL;
+}
+
+
+void call_set_current(struct list *calls, struct call *call)
+{
+	if (!calls || !call)
+		return;
+
+	list_unlink(&call->le);
+	list_append(calls, &call->le, call);
+}
diff --git a/src/core.h b/src/core.h
index dfedf57..27b3b76 100644
--- a/src/core.h
+++ b/src/core.h
@@ -136,6 +136,11 @@ int bfcp_start(struct bfcp *bfcp);
  * Call Control
  */
 
+enum {
+	CALL_LINENUM_MIN  =   1,
+	CALL_LINENUM_MAX  = 256
+};
+
 struct call;
 
 /** Call parameters */
diff --git a/src/ua.c b/src/ua.c
index 35626f7..41a80e7 100644
--- a/src/ua.c
+++ b/src/ua.c
@@ -1545,21 +1545,35 @@ int ua_print_sip_status(struct re_printf *pf, void *unused)
  */
 int ua_print_calls(struct re_printf *pf, const struct ua *ua)
 {
-	struct le *le;
+	uint32_t n, count=0;
+	uint32_t linenum;
 	int err = 0;
+
 	if (!ua) {
 		err |= re_hprintf(pf, "\n--- No active calls ---\n");
 		return err;
 	}
 
+	n = list_count(&ua->calls);
+
 	err |= re_hprintf(pf, "\n--- List of active calls (%u): ---\n",
-			  list_count(&ua->calls));
+			  n);
+
+	for (linenum=CALL_LINENUM_MIN; linenum<CALL_LINENUM_MAX; linenum++) {
 
-	for (le = ua->calls.head; le; le = le->next) {
+		const struct call *call;
 
-		const struct call *call = le->data;
+		call = call_find_linenum(&ua->calls, linenum);
+		if (call) {
+			++count;
 
-		err |= re_hprintf(pf, "  %H\n", call_info, call);
+			err |= re_hprintf(pf, "  %c %H\n",
+					  call == ua_call(ua) ? '>' : ' ',
+					  call_info, call);
+		}
+
+		if (count >= n)
+			break;
 	}
 
 	err |= re_hprintf(pf, "\n");