[mutter/wip/carlosg/input-refactors-pt1: 5/28] clutter: Limit number of touch slots available to a virtual touch device

[Carlos Garnacho <carlosg src gnome org>]

commit 70d4944e1590d13dcaadc7c3dd101e2ffcc5b6dd
Author: Carlos Garnacho <carlosg gnome org>
Date:   Thu Oct 22 11:18:34 2020 +0200

    clutter: Limit number of touch slots available to a virtual touch device
    
    It's not worth letting these devices have an "unlimited" range of touch
    slots. Limiting it to 32 is more than enough to map it with real touch
    devices nowadays.
    
    https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1486

 clutter/clutter/clutter-virtual-input-device.c | 12 +++++++++++
 clutter/clutter/clutter-virtual-input-device.h |  2 ++
 src/backends/meta-remote-desktop-session.c     | 28 ++++++++++++++++++++++++--
 3 files changed, 40 insertions(+), 2 deletions(-)
---
diff --git a/clutter/clutter/clutter-virtual-input-device.c b/clutter/clutter/clutter-virtual-input-device.c
index 522a6596fb..ff733a4647 100644
--- a/clutter/clutter/clutter-virtual-input-device.c
+++ b/clutter/clutter/clutter-virtual-input-device.c
@@ -151,6 +151,10 @@ clutter_virtual_input_device_notify_touch_down (ClutterVirtualInputDevice *virtu
   ClutterVirtualInputDeviceClass *klass =
     CLUTTER_VIRTUAL_INPUT_DEVICE_GET_CLASS (virtual_device);
 
+  g_return_if_fail (CLUTTER_IS_VIRTUAL_INPUT_DEVICE (virtual_device));
+  g_return_if_fail (slot >= 0 &&
+                    slot < CLUTTER_VIRTUAL_INPUT_DEVICE_MAX_TOUCH_SLOTS);
+
   klass->notify_touch_down (virtual_device, time_us,
                             slot, x, y);
 }
@@ -165,6 +169,10 @@ clutter_virtual_input_device_notify_touch_motion (ClutterVirtualInputDevice *vir
   ClutterVirtualInputDeviceClass *klass =
     CLUTTER_VIRTUAL_INPUT_DEVICE_GET_CLASS (virtual_device);
 
+  g_return_if_fail (CLUTTER_IS_VIRTUAL_INPUT_DEVICE (virtual_device));
+  g_return_if_fail (slot >= 0 &&
+                    slot < CLUTTER_VIRTUAL_INPUT_DEVICE_MAX_TOUCH_SLOTS);
+
   klass->notify_touch_motion (virtual_device, time_us,
                               slot, x, y);
 }
@@ -177,6 +185,10 @@ clutter_virtual_input_device_notify_touch_up (ClutterVirtualInputDevice *virtual
   ClutterVirtualInputDeviceClass *klass =
     CLUTTER_VIRTUAL_INPUT_DEVICE_GET_CLASS (virtual_device);
 
+  g_return_if_fail (CLUTTER_IS_VIRTUAL_INPUT_DEVICE (virtual_device));
+  g_return_if_fail (slot >= 0 &&
+                    slot < CLUTTER_VIRTUAL_INPUT_DEVICE_MAX_TOUCH_SLOTS);
+
   klass->notify_touch_up (virtual_device, time_us,
                           slot);
 }
diff --git a/clutter/clutter/clutter-virtual-input-device.h b/clutter/clutter/clutter-virtual-input-device.h
index b829c04ad5..fb357af1ee 100644
--- a/clutter/clutter/clutter-virtual-input-device.h
+++ b/clutter/clutter/clutter-virtual-input-device.h
@@ -31,6 +31,8 @@
 
 #define CLUTTER_TYPE_VIRTUAL_INPUT_DEVICE (clutter_virtual_input_device_get_type ())
 
+#define CLUTTER_VIRTUAL_INPUT_DEVICE_MAX_TOUCH_SLOTS 32u
+
 CLUTTER_EXPORT
 G_DECLARE_DERIVABLE_TYPE (ClutterVirtualInputDevice,
                           clutter_virtual_input_device,
diff --git a/src/backends/meta-remote-desktop-session.c b/src/backends/meta-remote-desktop-session.c
index 28191a1e08..27bd58b724 100644
--- a/src/backends/meta-remote-desktop-session.c
+++ b/src/backends/meta-remote-desktop-session.c
@@ -629,6 +629,14 @@ handle_notify_touch_down (MetaDBusRemoteDesktopSession *skeleton,
   if (!meta_remote_desktop_session_check_can_notify (session, invocation))
     return TRUE;
 
+  if (slot > CLUTTER_VIRTUAL_INPUT_DEVICE_MAX_TOUCH_SLOTS)
+    {
+      g_dbus_method_invocation_return_error (invocation, G_DBUS_ERROR,
+                                             G_DBUS_ERROR_FAILED,
+                                             "Touch slot out of range");
+      return TRUE;
+    }
+
   if (!session->screen_cast_session)
     {
       g_dbus_method_invocation_return_error (invocation, G_DBUS_ERROR,
@@ -676,6 +684,14 @@ handle_notify_touch_motion (MetaDBusRemoteDesktopSession *skeleton,
     return TRUE;
 
 
+  if (slot > CLUTTER_VIRTUAL_INPUT_DEVICE_MAX_TOUCH_SLOTS)
+    {
+      g_dbus_method_invocation_return_error (invocation, G_DBUS_ERROR,
+                                             G_DBUS_ERROR_FAILED,
+                                             "Touch slot out of range");
+      return TRUE;
+    }
+
   if (!session->screen_cast_session)
     {
       g_dbus_method_invocation_return_error (invocation, G_DBUS_ERROR,
@@ -709,14 +725,22 @@ handle_notify_touch_motion (MetaDBusRemoteDesktopSession *skeleton,
 
 static gboolean
 handle_notify_touch_up (MetaDBusRemoteDesktopSession *skeleton,
-                          GDBusMethodInvocation        *invocation,
-                          unsigned int                  slot)
+                        GDBusMethodInvocation        *invocation,
+                        unsigned int                  slot)
 {
   MetaRemoteDesktopSession *session = META_REMOTE_DESKTOP_SESSION (skeleton);
 
   if (!meta_remote_desktop_session_check_can_notify (session, invocation))
     return TRUE;
 
+  if (slot > CLUTTER_VIRTUAL_INPUT_DEVICE_MAX_TOUCH_SLOTS)
+    {
+      g_dbus_method_invocation_return_error (invocation, G_DBUS_ERROR,
+                                             G_DBUS_ERROR_FAILED,
+                                             "Touch slot out of range");
+      return TRUE;
+    }
+
   clutter_virtual_input_device_notify_touch_up (session->virtual_touchscreen,
                                                        CLUTTER_CURRENT_TIME,
                                                        slot);