Xi: add "deletable" flag to properties, add DeleteProperty handler.

A property can only be deleted if any of the following is true:
- if a property is deletable and all handlers return Success.
- if a property is non-deleteable and the all handlers return Success AND the
  delete request does not come from a client (i.e. driver or the server).

A client can never delete a non-deletable property.

2 files changed, 12 insertions, 1 deletions

diff --git a/include/exevents.h b/include/exevents.h
index c3a2ad610..4df0aee48 100644
--- a/include/exevents.h
+++ b/include/exevents.h
@@ -222,13 +222,21 @@ extern int XIGetDeviceProperty(
         XIPropertyValuePtr*     /* value */
 );
 
+extern int XISetDevicePropertyDeletable(
+        DeviceIntPtr            /* dev */,
+        Atom                    /* property */,
+        Bool                    /* deletable */
+);
+
 extern long XIRegisterPropertyHandler(
         DeviceIntPtr         dev,
         int (*SetProperty) (DeviceIntPtr dev,
                             Atom property,
                             XIPropertyValuePtr prop),
         int (*GetProperty) (DeviceIntPtr dev,
-                            Atom property)
+                            Atom property),
+        int (*DeleteProperty) (DeviceIntPtr dev,
+                               Atom property)
 );
 
 extern void XIUnRegisterPropertyHandler(
diff --git a/include/inputstr.h b/include/inputstr.h
index 93b32934d..65cb1b97f 100644
--- a/include/inputstr.h
+++ b/include/inputstr.h
@@ -353,6 +353,7 @@ typedef struct _XIProperty
 {
     struct _XIProperty   *next;
     Atom                  propertyName;
+    BOOL                  deletable;    /* clients can delete this prop? */
     XIPropertyValueRec    value;
 } XIPropertyRec;
 
@@ -369,6 +370,8 @@ typedef struct _XIPropertyHandler
                         XIPropertyValuePtr prop);
     int (*GetProperty) (DeviceIntPtr dev,
                         Atom property);
+    int (*DeleteProperty) (DeviceIntPtr dev,
+                           Atom property);
 } XIPropertyHandler, *XIPropertyHandlerPtr;
 
 /* states for devices */