[gnome-control-center/wip/gbsneto/new-keyboard-panel: 7/8] keyboard: bring back reverse item management

[Georges Basile Stavracas Neto <gbsneto src gnome org>]

commit 106b70f224ed8dd8b1d90e7d1e7121f90fbb2dd1
Author: Georges Basile Stavracas Neto <georges stavracas gmail com>
Date:   Thu Jul 21 18:32:28 2016 -0300

    keyboard: bring back reverse item management
    
    In order to simplify the porting to the new UI, the
    reverse item functionality was removed. Now that all
    the necessary code landed, it is time to bring it back.
    
    This patch adds back the ability to manage reverse items.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=769063

 panels/keyboard/cc-keyboard-item.c    |   53 +++++++++++++++++++++++-
 panels/keyboard/cc-keyboard-manager.c |   71 ++++++++++++++++++++------------
 2 files changed, 94 insertions(+), 30 deletions(-)
---
diff --git a/panels/keyboard/cc-keyboard-item.c b/panels/keyboard/cc-keyboard-item.c
index 0d2ea99..ddfa35a 100644
--- a/panels/keyboard/cc-keyboard-item.c
+++ b/panels/keyboard/cc-keyboard-item.c
@@ -147,17 +147,54 @@ _set_binding (CcKeyboardItem *item,
               const char     *value,
              gboolean        set_backend)
 {
-  g_free (item->priv->binding);
-  item->priv->binding = g_strdup (value);
+  CcKeyboardItem *reverse;
+  gboolean enabled;
+
+  reverse = item->priv->reverse_item;
+  enabled = value && strlen (value) > 0;
+
+  g_clear_pointer (&item->priv->binding, g_free);
+  if (enabled)
+    item->priv->binding = g_strdup (value);
+
   binding_from_string (item->priv->binding, &item->keyval,
                        &item->keycode, &item->mask);
 
+  /*
+   * Always treat the pair (item, reverse) as a unit: setting one also
+   * disables the other, disabling one up also sets the other.
+   */
+  if (reverse)
+    {
+      GdkModifierType reverse_mask;
+
+      reverse_mask = enabled ? item->mask ^ GDK_SHIFT_MASK : item->mask;
+
+      g_clear_pointer (&reverse->priv->binding, g_free);
+      if (enabled)
+        reverse->priv->binding = gtk_accelerator_name_with_keycode (NULL,
+                                                                    item->keyval,
+                                                                    item->keycode,
+                                                                    reverse_mask);
+
+      binding_from_string (reverse->priv->binding,
+                           &reverse->keyval,
+                           &reverse->keycode,
+                           &reverse->mask);
+    }
+
   if (set_backend == FALSE)
     return;
 
   settings_set_binding (item->settings, item->key, item->priv->binding);
 
   g_object_notify (G_OBJECT (item), "is-value-default");
+
+  if (reverse)
+    {
+      settings_set_binding (reverse->settings, reverse->key, reverse->priv->binding);
+      g_object_notify (G_OBJECT (reverse), "is-value-default");
+    }
 }
 
 static void
@@ -545,11 +582,21 @@ cc_keyboard_item_is_value_default (CcKeyboardItem *self)
 void
 cc_keyboard_item_reset (CcKeyboardItem *self)
 {
+  CcKeyboardItem *reverse;
+
   g_return_if_fail (CC_IS_KEYBOARD_ITEM (self));
 
-  g_settings_reset (self->settings, self->key);
+  reverse = self->priv->reverse_item;
 
+  g_settings_reset (self->settings, self->key);
   g_object_notify (G_OBJECT (self), "is-value-default");
+
+  /* Also reset the reverse item */
+  if (reverse)
+    {
+      g_settings_reset (reverse->settings, reverse->key);
+      g_object_notify (G_OBJECT (reverse), "is-value-default");
+    }
 }
 
 /*
diff --git a/panels/keyboard/cc-keyboard-manager.c b/panels/keyboard/cc-keyboard-manager.c
index 10c340a..fc19d2d 100644
--- a/panels/keyboard/cc-keyboard-manager.c
+++ b/panels/keyboard/cc-keyboard-manager.c
@@ -96,35 +96,53 @@ get_binding_from_variant (GVariant *variant)
 }
 
 static gboolean
+is_shortcut_different (CcUniquenessData *data,
+                       CcKeyboardItem   *item)
+{
+  if (data->orig_item && cc_keyboard_item_equal (data->orig_item, item))
+    return FALSE;
+
+  if (data->new_keyval != 0)
+    {
+      if (data->new_keyval != item->keyval)
+        return TRUE;
+    }
+  else if (item->keyval != 0 || data->new_keycode != item->keycode)
+    {
+      return TRUE;
+    }
+
+  return FALSE;
+}
+
+static gboolean
 compare_keys_for_uniqueness (CcKeyboardItem   *current_item,
                              CcUniquenessData *data)
 {
-  CcKeyboardItem *item;
-
-  item = data->orig_item;
+  CcKeyboardItem *reverse_item;
 
   /* No conflict for: blanks, different modifiers or ourselves */
   if (!current_item ||
-      item == current_item ||
+      data->orig_item == current_item ||
       data->new_mask != current_item->mask)
     {
       return FALSE;
     }
 
-  if (item && cc_keyboard_item_equal (item, current_item))
-    goto out;
+  reverse_item = cc_keyboard_item_get_reverse_item (current_item);
 
-  if (data->new_keyval != 0)
-    {
-      if (data->new_keyval != current_item->keyval)
-          return FALSE;
-    }
-  else if (current_item->keyval != 0 || data->new_keycode != current_item->keycode)
-    {
-      return FALSE;
-    }
+  /* When the current item is the reversed shortcut of a main item, simply ignore it */
+  if (reverse_item && cc_keyboard_item_is_hidden (current_item))
+    return FALSE;
+
+  if (is_shortcut_different (data, current_item))
+    return FALSE;
 
-out:
+  /* Also check for the reverse item if any */
+  if (reverse_item && is_shortcut_different (data, reverse_item))
+    return FALSE;
+
+  /* No tests failed and we found a conflict */
   data->conflict_item = current_item;
 
   return TRUE;
@@ -933,6 +951,7 @@ cc_keyboard_manager_get_collision (CcKeyboardManager *self,
                                    gint               keycode)
 {
   CcUniquenessData data;
+  BindingGroupType i;
 
   g_return_val_if_fail (CC_IS_KEYBOARD_MANAGER (self), NULL);
 
@@ -943,21 +962,19 @@ cc_keyboard_manager_get_collision (CcKeyboardManager *self,
   data.conflict_item = NULL;
 
   /* Any number of shortcuts can be disabled */
-  if (keyval != 0 || keycode != 0)
-    {
-      BindingGroupType i;
+  if (keyval == 0 && keycode == 0)
+    return NULL;
 
-      for (i = BINDING_GROUP_SYSTEM; i <= BINDING_GROUP_USER && !data.conflict_item; i++)
-        {
-          GHashTable *table;
+  for (i = BINDING_GROUP_SYSTEM; i <= BINDING_GROUP_USER && !data.conflict_item; i++)
+    {
+      GHashTable *table;
 
-          table = get_hash_for_group (self, i);
+      table = get_hash_for_group (self, i);
 
-          if (!table)
-            continue;
+      if (!table)
+        continue;
 
-          g_hash_table_find (table, (GHRFunc) check_for_uniqueness, &data);
-        }
+      g_hash_table_find (table, (GHRFunc) check_for_uniqueness, &data);
     }
 
   return data.conflict_item;