[gnome-control-center/wip/gbsneto/new-keyboard-panel: 5/5] keyboard: bring back reverse item management

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

commit 39dca53f2d52c8901c1772b423ae900892f61a98
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 readds the ability to manage reverse items.

 panels/keyboard/cc-keyboard-item.c    |   54 +++++++++++++++++++++++--
 panels/keyboard/cc-keyboard-manager.c |   71 ++++++++++++++++++++------------
 2 files changed, 94 insertions(+), 31 deletions(-)
---
diff --git a/panels/keyboard/cc-keyboard-item.c b/panels/keyboard/cc-keyboard-item.c
index 7194a6a..884856e 100644
--- a/panels/keyboard/cc-keyboard-item.c
+++ b/panels/keyboard/cc-keyboard-item.c
@@ -147,17 +147,53 @@ _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-modified");
+
+  if (reverse)
+    {
+      settings_set_binding (reverse->settings, reverse->key, reverse->priv->binding);
+      g_object_notify (G_OBJECT (reverse), "is-modified");
+    }
 }
 
 static void
@@ -545,11 +581,21 @@ cc_keyboard_item_is_modified (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-modified");
+
+  /* Also reset the reverse item */
+  if (reverse)
+    {
+      g_settings_reset (reverse->settings, reverse->key);
+      g_object_notify (G_OBJECT (reverse), "is-modified");
+    }
 }
 
 /*
diff --git a/panels/keyboard/cc-keyboard-manager.c b/panels/keyboard/cc-keyboard-manager.c
index d418e8a..a71fdaf 100644
--- a/panels/keyboard/cc-keyboard-manager.c
+++ b/panels/keyboard/cc-keyboard-manager.c
@@ -94,35 +94,53 @@ 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;
@@ -931,6 +949,7 @@ cc_keyboard_manager_get_collision (CcKeyboardManager *self,
                                    gint               keycode)
 {
   CcUniquenessData data;
+  BindingGroupType i;
 
   g_return_val_if_fail (CC_IS_KEYBOARD_MANAGER (self), NULL);
 
@@ -941,21 +960,19 @@ 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;