[gnome-flashback] input-settings: re-add support for edge scrolling with some touchpads

[Alberts Muktupāvels <muktupavels src gnome org>]

commit a50e70e07546b1f978178cc82a8b6548c9cf0381
Author: Bastien Nocera <hadess hadess net>
Date:   Thu Jun 30 14:27:23 2016 +0200

    input-settings: re-add support for edge scrolling with some touchpads
    
    Add support for setting edge-scrolling separately from two-finger
    scrolling. We now have 2 separate boolean settings for those, with the
    Mouse panel in gnome-control-center allowing to set only one of those at
    a time, but nothing precludes both being set in the configuration.
    
    We need to handle:
    - two-finger-scrolling-enabled and edge-scrolling-enabled settings both
      being set.
    - those 2 settings being change out-of-order
    - two-finger-scrolling being set on a device that doesn't support it
    - edge-scrolling-enabled on a device that doesn't support it
    
    And the combinations of one touchpad supporting just one of edge
    scrolling and two-finger scrolling and another vice-versa.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=768245
    
    Original commit:
    https://git.gnome.org/browse/mutter/commit/?id=36cd7177fd40432cb4ae7db10e2571dbbd9604b9

 configure.ac                                       |    2 +-
 .../libinput-settings/gf-input-settings.c          |  117 ++++++++++++++++++--
 2 files changed, 108 insertions(+), 11 deletions(-)
---
diff --git a/configure.ac b/configure.ac
index 54b7c03..89741e2 100644
--- a/configure.ac
+++ b/configure.ac
@@ -110,7 +110,7 @@ GTK_REQUIRED=3.19.5
 LIBGNOME_DESKTOP_REQUIRED=3.12.0
 CANBERRA_REQUIRED=0.13
 GLIB_REQUIRED=2.44.0
-GSETTINGS_DESKTOP_SCHEMAS_REQUIRED=3.21.3
+GSETTINGS_DESKTOP_SCHEMAS_REQUIRED=3.21.4
 POLKIT_AGENT_REQUIRED=0.97
 POLKIT_GOBJECT_REQUIRED=0.97
 IBUS_REQUIRED=1.5.2
diff --git a/gnome-flashback/libinput-settings/gf-input-settings.c 
b/gnome-flashback/libinput-settings/gf-input-settings.c
index 52bfe69..5eff59d 100644
--- a/gnome-flashback/libinput-settings/gf-input-settings.c
+++ b/gnome-flashback/libinput-settings/gf-input-settings.c
@@ -349,32 +349,102 @@ set_edge_scroll (GfInputSettings *settings,
                  gboolean         edge_scroll_enabled)
 {
   guchar *available;
+  guchar *defaults;
   guchar values[3] = { 0 }; /* 2fg, edge, button. The last value is unused */
 
   available = get_property (settings, device,
                             "libinput Scroll Methods Available",
                             XA_INTEGER, 8, 3);
 
-  if (!available)
-    return;
+  defaults = get_property (settings, device,
+                           "libinput Scroll Method Enabled",
+                           XA_INTEGER, 8, 3);
+
+  if (!available || !defaults)
+    {
+      if (available)
+        XFree (available);
+
+      if (defaults)
+        XFree (defaults);
+
+      return;
+    }
+
+  memcpy (values, defaults, 3);
+
+  /* Don't set edge scrolling if two-finger scrolling is enabled and available */
+  if (available[1] && !(available[0] && values[0]))
+    {
+      values[1] = !!edge_scroll_enabled;
+
+      change_property (settings, device, "libinput Scroll Method Enabled",
+                       XA_INTEGER, 8, &values, 3);
+    }
+
+  if (available)
+    XFree (available);
+
+  if (defaults)
+    XFree (defaults);
+}
+
+static void
+set_two_finger_scroll (GfInputSettings *settings,
+                       GdkDevice       *device,
+                       gboolean         two_finger_scroll_enabled)
+{
+  guchar *available;
+  gboolean changed;
+  guchar *defaults;
+  guchar values[3] = { 0 }; /* 2fg, edge, button. The last value is unused */
+
+  available = get_property (settings, device,
+                            "libinput Scroll Methods Available",
+                            XA_INTEGER, 8, 3);
+
+  defaults = get_property (settings, device,
+                           "libinput Scroll Method Enabled",
+                           XA_INTEGER, 8, 3);
+
+  if (!available || !defaults)
+    {
+      if (available)
+        XFree (available);
+
+      if (defaults)
+        XFree (defaults);
+
+      return;
+    }
+
+  memcpy (values, defaults, 3);
+  changed = FALSE;
 
   if (available[0])
     {
-      values[0] = 1;
+      values[0] = !!two_finger_scroll_enabled;
+      changed = TRUE;
     }
-  else if (available[1] && edge_scroll_enabled)
+
+  /* Disable edge scrolling when two-finger scrolling is enabled */
+  if (values[0] && values[1])
     {
-      values[1] = 1;
+      values[1] = 0;
+      changed = TRUE;
     }
-  else
+
+  if (changed)
     {
-      /* Disabled */
+      change_property (settings, device, "libinput Scroll Method Enabled",
+                       XA_INTEGER, 8, &values, 3);
     }
 
-  change_property (settings, device, "libinput Scroll Method Enabled",
-                   XA_INTEGER, 8, &values, 3);
+  if (available)
+    XFree (available);
 
-  XFree (available);
+  if (defaults)
+    XFree (defaults);
 }
 
 static void
@@ -656,6 +726,30 @@ update_touchpad_edge_scroll (GfInputSettings *settings,
 }
 
 static void
+update_touchpad_two_finger_scroll (GfInputSettings *settings,
+                                   GdkDevice       *device)
+{
+  gboolean two_finger_scroll_enabled;
+
+  if (device && gdk_device_get_source (device) != GDK_SOURCE_TOUCHPAD)
+    return;
+
+  two_finger_scroll_enabled = g_settings_get_boolean (settings->touchpad,
+                                                      "two-finger-scrolling-enabled");
+
+  if (device)
+    {
+      device_set_bool_setting (settings, device,
+                               set_two_finger_scroll, two_finger_scroll_enabled);
+    }
+  else
+    {
+      set_bool_setting (settings, GDK_SOURCE_TOUCHPAD,
+                        set_two_finger_scroll, two_finger_scroll_enabled);
+    }
+}
+
+static void
 update_touchpad_click_method (GfInputSettings *settings,
                               GdkDevice       *device)
 {
@@ -768,6 +862,8 @@ settings_changed_cb (GSettings       *gsettings,
         update_touchpad_send_events (settings, NULL);
       else if (strcmp (key, "edge-scrolling-enabled") == 0)
         update_touchpad_edge_scroll (settings, NULL);
+      else if (strcmp (key, "two-finger-scrolling-enabled") == 0)
+        update_touchpad_two_finger_scroll (settings, NULL);
       else if (strcmp (key, "click-method") == 0)
         update_touchpad_click_method (settings, NULL);
     }
@@ -972,6 +1068,7 @@ apply_device_settings (GfInputSettings *settings,
   update_touchpad_tap_enabled (settings, device);
   update_touchpad_send_events (settings, device);
   update_touchpad_edge_scroll (settings, device);
+  update_touchpad_two_finger_scroll (settings, device);
   update_touchpad_click_method (settings, device);
 
   update_trackball_scroll_button (settings, device);