[Spice-devel] [PATCH spice-gtk 5/5] widget: differentiate key press & release from press only events

[Marc-André Lureau]

Until now, Spice clients only sent seperate key events for press and
release. But this may result in unwanted key repeatition from guest VM
side. It seems OSes have various implementation. While MS Windows rely
on hardware key repeats (which are several sequential press events),
otoh, X11 uses software key repeat (although not Linux keyboard/VT by
default).

We can't easily disable guest side repeaters, as it may be enforced by
other components (a X11 client can adjust each key individually, or
the desktop settings may change it etc.). Neither can we rely only on
guest software repeater as Windows doesn't seem to have one by
default, so we need to keep sending multiple press events as of today.

It seems a nice way to improve the situation is to send a single
"press&release" key event when the user released the key within a
short delay. If the key is pressed for longer, we keep the exisiting
behaviour which has been working pretty well so far, sending seperate
"press", then repeatedly "press", and an ending "release" event.
---
 gtk/spice-widget-priv.h |    2 ++
 gtk/spice-widget.c      |   76 +++++++++++++++++++++++++++++++++++++++++++----
 spice-common            |    2 +-
 3 files changed, 73 insertions(+), 7 deletions(-)

diff --git a/gtk/spice-widget-priv.h b/gtk/spice-widget-priv.h
index 97c6489..87d1de9 100644
--- a/gtk/spice-widget-priv.h
+++ b/gtk/spice-widget-priv.h
@@ -106,6 +106,8 @@ struct _SpiceDisplayPrivate {
     const guint16 const     *keycode_map;
     size_t                  keycode_maplen;
     uint32_t                key_state[512 / 32];
+    int                     key_delayed_scancode;
+    guint                   key_delayed_id;
     SpiceGrabSequence         *grabseq; /* the configured key sequence */
     gboolean                *activeseq; /* the currently pressed keys */
     gint                    mark;
diff --git a/gtk/spice-widget.c b/gtk/spice-widget.c
index 8cb7abb..d2b00f7 100644
--- a/gtk/spice-widget.c
+++ b/gtk/spice-widget.c
@@ -393,6 +393,11 @@ static void spice_display_dispose(GObject *obj)
     g_clear_object(&d->session);
     d->gtk_session = NULL;
 
+    if (d->key_delayed_id) {
+        g_source_remove(d->key_delayed_id);
+        d->key_delayed_id = 0;
+    }
+
     G_OBJECT_CLASS(spice_display_parent_class)->dispose(obj);
 }
 
@@ -994,6 +999,40 @@ typedef enum {
     SEND_KEY_RELEASE,
 } SendKeyType;
 
+static void key_press_and_release(SpiceDisplay *display)
+{
+    SpiceDisplayPrivate *d = SPICE_DISPLAY_GET_PRIVATE(display);
+
+    if (d->key_delayed_scancode == 0)
+        return;
+
+    spice_inputs_key_press_and_release(d->inputs, d->key_delayed_scancode);
+    d->key_delayed_scancode = 0;
+
+    if (d->key_delayed_id) {
+        g_source_remove(d->key_delayed_id);
+        d->key_delayed_id = 0;
+    }
+}
+
+static gboolean key_press_delayed(gpointer data)
+{
+    SpiceDisplayPrivate *d = SPICE_DISPLAY_GET_PRIVATE(data);
+
+    if (d->key_delayed_scancode == 0)
+        goto end;
+
+    spice_inputs_key_press(d->inputs, d->key_delayed_scancode);
+    d->key_delayed_scancode = 0;
+
+    if (d->key_delayed_id)
+        g_source_remove(d->key_delayed_id);
+
+end:
+    d->key_delayed_id = 0;
+    return FALSE;
+}
+
 static void send_key(SpiceDisplay *display, int scancode, SendKeyType type, gboolean press_delayed)
 {
     SpiceDisplayPrivate *d = SPICE_DISPLAY_GET_PRIVATE(display);
@@ -1010,15 +1049,40 @@ static void send_key(SpiceDisplay *display, int scancode, SendKeyType type, gboo
     m = (1 << b);
     g_return_if_fail(i < SPICE_N_ELEMENTS(d->key_state));
 
-    if (down) {
-        spice_inputs_key_press(d->inputs, scancode);
+    switch (type) {
+    case SEND_KEY_PRESS:
+        /* ensure delayed key is pressed before any new input event */
+        key_press_delayed(display);
+
+        if (press_delayed &&
+            d->keypress_delay != 0 &&
+            !(d->key_state[i] & m)) {
+            g_warn_if_fail(d->key_delayed_id == 0);
+            d->key_delayed_id = g_timeout_add(d->keypress_delay, key_press_delayed, display);
+            d->key_delayed_scancode = scancode;
+        } else
+            spice_inputs_key_press(d->inputs, scancode);
+
         d->key_state[i] |= m;
-    } else {
-        if (!(d->key_state[i] & m)) {
-            return;
+        break;
+
+    case SEND_KEY_RELEASE:
+        if (!(d->key_state[i] & m))
+            break;
+
+        if (d->key_delayed_scancode == scancode)
+            key_press_and_release(display);
+        else {
+            /* ensure delayed key is pressed before other key are released */
+            key_press_delayed(display);
+            spice_inputs_key_release(d->inputs, scancode);
         }
-        spice_inputs_key_release(d->inputs, scancode);
+
         d->key_state[i] &= ~m;
+        break;
+
+    default:
+        g_warn_if_reached();
     }
 }
 
diff --git a/spice-common b/spice-common
index c2adbb0..31f1bff 160000
--- a/spice-common
+++ b/spice-common
@@ -1 +1 @@
-Subproject commit c2adbb00dc0b29de0fe297f241fb0efeb4a81510
+Subproject commit 31f1bff472da61ba07121ed31536c4af864c4a8f
-- 
1.7.10.4