[Qemu-devel] [PATCH 15/17] monitor: Improve mux'ed console experience

[Jan Kiszka]

Up to now, you never really knew if you already switched the console
after pressing CTRL-A C or if you mistyped it again. This patch
clarifies the situation by providing a prompt in a new line and
injecting a linebreak when switching away again. For this purpose, the
two events CHR_EVENT_MUX_IN and CHR_EVENT_MUX_OUT are introduced and
distributed on focus switches.

Signed-off-by: Jan Kiszka <address@hidden>
---

 monitor.c   |   26 ++++++++++++++++++++------
 qemu-char.c |   11 +++++++++--
 qemu-char.h |    8 +++++---
 3 files changed, 34 insertions(+), 11 deletions(-)

diff --git a/monitor.c b/monitor.c
index 498b223..2306b10 100644
--- a/monitor.c
+++ b/monitor.c
@@ -2868,15 +2868,29 @@ static void term_event(void *opaque, int event)
 {
     MonitorTerm *old_term = cur_term;
 
-    if (event != CHR_EVENT_RESET)
-       return;
-
     cur_term = opaque;
 
-    monitor_printf("QEMU %s monitor - type 'help' for more information\n",
-                   QEMU_VERSION);
-    monitor_resume(cur_term);
+    switch (event) {
+    case CHR_EVENT_MUX_IN:
+        readline_restart(cur_term->rs);
+        monitor_resume(cur_term);
+        monitor_flush();
+        break;
 
+    case CHR_EVENT_MUX_OUT:
+        if (cur_term->suspend_cnt == 0)
+            monitor_printf("\n");
+        monitor_flush();
+        monitor_suspend();
+        break;
+
+    case CHR_EVENT_RESET:
+        monitor_printf("QEMU %s monitor - type 'help' for more information\n",
+                       QEMU_VERSION);
+        if (cur_term->chr->focus == 0)
+            monitor_resume(cur_term);
+        break;
+    }
     cur_term = old_term;
 }
 
diff --git a/qemu-char.c b/qemu-char.c
index db2fb44..d107c53 100644
--- a/qemu-char.c
+++ b/qemu-char.c
@@ -294,6 +294,12 @@ static void mux_print_help(CharDriverState *chr)
     }
 }
 
+static void mux_chr_send_event(MuxDriver *d, int mux_nr, int event)
+{
+    if (d->chr_event[mux_nr])
+        d->chr_event[mux_nr](d->ext_opaque[mux_nr], event);
+}
+
 static int mux_proc_byte(CharDriverState *chr, MuxDriver *d, int ch)
 {
     if (d->term_got_escape) {
@@ -325,9 +331,11 @@ static int mux_proc_byte(CharDriverState *chr, MuxDriver 
*d, int ch)
             break;
         case 'c':
             /* Switch to the next registered device */
+            mux_chr_send_event(d, chr->focus, CHR_EVENT_MUX_OUT);
             chr->focus++;
             if (chr->focus >= d->mux_cnt)
                 chr->focus = 0;
+            mux_chr_send_event(d, chr->focus, CHR_EVENT_MUX_IN);
             break;
        case 't':
            term_timestamps = !term_timestamps;
@@ -397,8 +405,7 @@ static void mux_chr_event(void *opaque, int event)
 
     /* Send the event to all registered listeners */
     for (i = 0; i < d->mux_cnt; i++)
-        if (d->chr_event[i])
-            d->chr_event[i](d->ext_opaque[i], event);
+        mux_chr_send_event(d, i, event);
 }
 
 static void mux_chr_update_read_handler(CharDriverState *chr)
diff --git a/qemu-char.h b/qemu-char.h
index bc0fcf3..b936244 100644
--- a/qemu-char.h
+++ b/qemu-char.h
@@ -4,9 +4,11 @@
 #include "sys-queue.h"
 /* character device */
 
-#define CHR_EVENT_BREAK 0 /* serial break char */
-#define CHR_EVENT_FOCUS 1 /* focus to this terminal (modal input needed) */
-#define CHR_EVENT_RESET 2 /* new connection established */
+#define CHR_EVENT_BREAK   0 /* serial break char */
+#define CHR_EVENT_FOCUS   1 /* focus to this terminal (modal input needed) */
+#define CHR_EVENT_RESET   2 /* new connection established */
+#define CHR_EVENT_MUX_IN  3 /* mux-focus was set to this terminal */
+#define CHR_EVENT_MUX_OUT 4 /* mux-focus will move on */
 
 
 #define CHR_IOCTL_SERIAL_SET_PARAMS   1