[gnome-settings-daemon] common: Add X property setting helper

[Bastien Nocera <hadess src gnome org>]

commit f1e81e32ecfd9108629c13a2e8d24e64a1869ed8
Author: Bastien Nocera <hadess hadess net>
Date:   Tue May 31 12:03:50 2011 +0100

    common: Add X property setting helper
    
    From the wacom plugin, thanks Peter.

 plugins/common/gsd-input-helper.c |   51 +++++++++++++++++++++++++++++++++++++
 plugins/common/gsd-input-helper.h |   27 ++++++++++++++++---
 2 files changed, 74 insertions(+), 4 deletions(-)
---
diff --git a/plugins/common/gsd-input-helper.c b/plugins/common/gsd-input-helper.c
index 7215b48..07c2b92 100644
--- a/plugins/common/gsd-input-helper.c
+++ b/plugins/common/gsd-input-helper.c
@@ -35,6 +35,57 @@ typedef gboolean (* InfoIdentifyFunc) (XDeviceInfo *device_info);
 typedef gboolean (* DeviceIdentifyFunc) (XDevice *xdevice);
 
 gboolean
+device_set_property (XDevice        *xdevice,
+                     const char     *device_name,
+                     PropertyHelper *property)
+{
+        int rc;
+        Atom prop;
+        Atom realtype;
+        int realformat;
+        unsigned long nitems, bytes_after;
+        unsigned char *data;
+
+        prop = XInternAtom (GDK_DISPLAY_XDISPLAY (gdk_display_get_default ()),
+                            property->name, False);
+        if (!prop)
+                return FALSE;
+
+        gdk_error_trap_push ();
+
+        rc = XGetDeviceProperty (GDK_DISPLAY_XDISPLAY (gdk_display_get_default ()),
+                                 xdevice, prop, 0, property->nitems, False,
+                                 XA_INTEGER, &realtype, &realformat, &nitems,
+                                 &bytes_after, &data);
+
+        if (rc == Success && realtype == XA_INTEGER &&
+            realformat == property->format && nitems >= property->nitems) {
+                int i;
+                for (i = 0; i < nitems; i++) {
+                        switch (property->format) {
+                                case 8:
+                                        data[i] = property->data.c[i];
+                                        break;
+                                case 32:
+                                        ((long*)data)[i] = property->data.i[i];
+                                        break;
+                        }
+                }
+
+                XChangeDeviceProperty (GDK_DISPLAY_XDISPLAY (gdk_display_get_default ()),
+                                       xdevice, prop, XA_INTEGER, realformat,
+                                       PropModeReplace, data, nitems);
+        }
+
+        if (gdk_error_trap_pop ()) {
+                g_warning ("Error in setting \"%s\" for \"%s\"", property->name, device_name);
+                return FALSE;
+        }
+
+        return TRUE;
+}
+
+gboolean
 supports_xinput_devices (void)
 {
         gint op_code, event, error;
diff --git a/plugins/common/gsd-input-helper.h b/plugins/common/gsd-input-helper.h
index 6f405d0..727ed90 100644
--- a/plugins/common/gsd-input-helper.h
+++ b/plugins/common/gsd-input-helper.h
@@ -28,11 +28,26 @@ G_BEGIN_DECLS
 #include <X11/extensions/XIproto.h>
 
 typedef enum {
-	COMMAND_DEVICE_ADDED,
-	COMMAND_DEVICE_REMOVED,
-	COMMAND_DEVICE_PRESENT
+        COMMAND_DEVICE_ADDED,
+        COMMAND_DEVICE_REMOVED,
+        COMMAND_DEVICE_PRESENT
 } CustomCommand;
 
+/* Generic property setting code. Fill up the struct property with the property
+ * data and pass it into device_set_property together with the device to be
+ * changed.  Note: doesn't cater for non-zero offsets yet, but we don't have
+ * any settings that require that.
+ */
+typedef struct {
+        const char *name;       /* property name */
+        gint nitems;            /* number of items in data */
+        gint format;            /* CARD8 or CARD32 sized-items */
+        union {
+                const gchar *c; /* 8 bit data */
+                const gint *i;  /* 32 bit data */
+        } data;
+} PropertyHelper;
+
 gboolean  supports_xinput_devices (void);
 gboolean  device_is_touchpad      (XDevice                *xdevice);
 
@@ -42,8 +57,12 @@ gboolean  device_info_is_touchscreen (XDeviceInfo         *device_info);
 gboolean  touchpad_is_present     (void);
 gboolean  touchscreen_is_present  (void);
 
+gboolean  device_set_property     (XDevice                *xdevice,
+                                   const char             *device_name,
+                                   PropertyHelper         *property);
+
 gboolean  run_custom_command      (GdkDevice              *device,
-			           CustomCommand           command);
+                                   CustomCommand           command);
 
 G_END_DECLS