[gimp] pdb: add proper error messages for gimp_image_reorder_item()

[Michael Natterer <mitch src gnome org>]

commit ab852d74095acd4e2ae7f53f204762b59e28531c
Author: Michael Natterer <mitch gimp org>
Date:   Tue Aug 31 17:07:27 2010 +0200

    pdb: add proper error messages for gimp_image_reorder_item()

 app/pdb/gimppdb-utils.c    |   83 +++++++++++++++++++++++++++++++++++++++++--
 app/pdb/gimppdb-utils.h    |    9 +++++
 app/pdb/image-cmds.c       |   11 ++----
 tools/pdbgen/pdb/image.pdb |   11 ++----
 4 files changed, 94 insertions(+), 20 deletions(-)
---
diff --git a/app/pdb/gimppdb-utils.c b/app/pdb/gimppdb-utils.c
index 76b298d..cb45070 100644
--- a/app/pdb/gimppdb-utils.c
+++ b/app/pdb/gimppdb-utils.c
@@ -315,7 +315,7 @@ gimp_pdb_item_is_attached (GimpItem  *item,
   if (! gimp_item_is_attached (item))
     {
       g_set_error (error, GIMP_PDB_ERROR, GIMP_PDB_INVALID_ARGUMENT,
-                   _("Item '%s' (%d) can not be used because it has not "
+                   _("Item '%s' (%d) cannot be used because it has not "
                      "been added to an image"),
                    gimp_object_get_name (item),
                    gimp_item_get_ID (item));
@@ -325,7 +325,7 @@ gimp_pdb_item_is_attached (GimpItem  *item,
   if (image && image != gimp_item_get_image (item))
     {
       g_set_error (error, GIMP_PDB_ERROR, GIMP_PDB_INVALID_ARGUMENT,
-                   _("Item '%s' (%d) can not be used because it is "
+                   _("Item '%s' (%d) cannot be used because it is "
                      "attached to another image"),
                    gimp_object_get_name (item),
                    gimp_item_get_ID (item));
@@ -354,7 +354,7 @@ gimp_pdb_item_is_in_tree (GimpItem   *item,
   if (! gimp_item_get_tree (item))
     {
       g_set_error (error, GIMP_PDB_ERROR, GIMP_PDB_INVALID_ARGUMENT,
-                   _("Item '%s' (%d) can not be used because it is not "
+                   _("Item '%s' (%d) cannot be used because it is not "
                      "a direct child of an item tree"),
                    gimp_object_get_name (item),
                    gimp_item_get_ID (item));
@@ -365,6 +365,61 @@ gimp_pdb_item_is_in_tree (GimpItem   *item,
 }
 
 gboolean
+gimp_pdb_item_is_in_same_tree (GimpItem   *item,
+                               GimpItem   *item2,
+                               GimpImage  *image,
+                               GError    **error)
+{
+  g_return_val_if_fail (GIMP_IS_ITEM (item), FALSE);
+  g_return_val_if_fail (GIMP_IS_ITEM (item2), FALSE);
+  g_return_val_if_fail (image == NULL || GIMP_IS_IMAGE (image), FALSE);
+  g_return_val_if_fail (error == NULL || *error == NULL, FALSE);
+
+  if (! gimp_pdb_item_is_in_tree (item, image, FALSE, error) ||
+      ! gimp_pdb_item_is_in_tree (item2, image, FALSE, error))
+    return FALSE;
+
+  if (gimp_item_get_tree (item) != gimp_item_get_tree (item2))
+    {
+      g_set_error (error, GIMP_PDB_ERROR, GIMP_PDB_INVALID_ARGUMENT,
+                   _("Items '%s' (%d) and '%s' (%d) cannot be used "
+                     "because they are not part of the same item tree"),
+                   gimp_object_get_name (item),
+                   gimp_item_get_ID (item),
+                   gimp_object_get_name (item2),
+                   gimp_item_get_ID (item2));
+      return FALSE;
+    }
+
+  return TRUE;
+}
+
+gboolean
+gimp_pdb_item_is_not_ancestor (GimpItem  *item,
+                               GimpItem  *not_descendant,
+                               GError   **error)
+{
+  g_return_val_if_fail (GIMP_IS_ITEM (item), FALSE);
+  g_return_val_if_fail (GIMP_IS_ITEM (not_descendant), FALSE);
+  g_return_val_if_fail (error == NULL || *error == NULL, FALSE);
+
+  if (gimp_viewable_is_ancestor (GIMP_VIEWABLE (item),
+                                 GIMP_VIEWABLE (not_descendant)))
+    {
+      g_set_error (error, GIMP_PDB_ERROR, GIMP_PDB_INVALID_ARGUMENT,
+                   _("Item '%s' (%d) must not be an ancestor of "
+                     "'%s' (%d)"),
+                   gimp_object_get_name (item),
+                   gimp_item_get_ID (item),
+                   gimp_object_get_name (not_descendant),
+                   gimp_item_get_ID (not_descendant));
+      return FALSE;
+    }
+
+  return TRUE;
+}
+
+gboolean
 gimp_pdb_item_is_floating (GimpItem  *item,
                            GimpImage *dest_image,
                            GError   **error)
@@ -414,6 +469,26 @@ gimp_pdb_item_is_writable (GimpItem  *item,
 }
 
 gboolean
+gimp_pdb_item_is_group (GimpItem  *item,
+                        GError   **error)
+{
+  g_return_val_if_fail (GIMP_IS_ITEM (item), FALSE);
+  g_return_val_if_fail (error == NULL || *error == NULL, FALSE);
+
+  if (! gimp_viewable_get_children (GIMP_VIEWABLE (item)))
+    {
+      g_set_error (error, GIMP_PDB_ERROR, GIMP_PDB_INVALID_ARGUMENT,
+                   _("Item '%s' (%d) cannot be used because it is "
+                     "not a group item"),
+                   gimp_object_get_name (item),
+                   gimp_item_get_ID (item));
+      return FALSE;
+    }
+
+  return TRUE;
+}
+
+gboolean
 gimp_pdb_item_is_not_group (GimpItem  *item,
                             GError   **error)
 {
@@ -444,7 +519,7 @@ gimp_pdb_layer_is_text_layer (GimpLayer  *layer,
   if (! gimp_drawable_is_text_layer (GIMP_DRAWABLE (layer)))
     {
       g_set_error (error, GIMP_PDB_ERROR, GIMP_PDB_INVALID_ARGUMENT,
-                   _("Layer '%s' (%d) can not be used because it is not "
+                   _("Layer '%s' (%d) cannot be used because it is not "
                      "a text layer"),
                    gimp_object_get_name (layer),
                    gimp_item_get_ID (GIMP_ITEM (layer)));
diff --git a/app/pdb/gimppdb-utils.h b/app/pdb/gimppdb-utils.h
index f5a8a59..d25a23a 100644
--- a/app/pdb/gimppdb-utils.h
+++ b/app/pdb/gimppdb-utils.h
@@ -56,11 +56,20 @@ gboolean        gimp_pdb_item_is_in_tree        (GimpItem           *item,
                                                  GimpImage          *image,
                                                  gboolean            writable,
                                                  GError            **error);
+gboolean        gimp_pdb_item_is_in_same_tree   (GimpItem           *item,
+                                                 GimpItem           *item2,
+                                                 GimpImage          *image,
+                                                 GError            **error);
+gboolean        gimp_pdb_item_is_not_ancestor   (GimpItem           *item,
+                                                 GimpItem           *not_descendant,
+                                                 GError            **error);
 gboolean        gimp_pdb_item_is_floating       (GimpItem           *item,
                                                  GimpImage          *dest_image,
                                                  GError            **error);
 gboolean        gimp_pdb_item_is_writable       (GimpItem           *item,
                                                  GError            **error);
+gboolean        gimp_pdb_item_is_group          (GimpItem           *item,
+                                                 GError            **error);
 gboolean        gimp_pdb_item_is_not_group      (GimpItem           *item,
                                                  GError            **error);
 
diff --git a/app/pdb/image-cmds.c b/app/pdb/image-cmds.c
index 145b73d..df4c6cb 100644
--- a/app/pdb/image-cmds.c
+++ b/app/pdb/image-cmds.c
@@ -1246,14 +1246,9 @@ image_reorder_item_invoker (GimpProcedure      *procedure,
     {
       if (gimp_pdb_item_is_in_tree (item, image, FALSE, error) &&
           (parent == NULL ||
-           gimp_pdb_item_is_in_tree (parent, image, FALSE, error)) &&
-          (parent == NULL ||
-           gimp_item_get_tree (item) == gimp_item_get_tree (parent)) &&
-          (parent == NULL ||
-           gimp_viewable_get_children (GIMP_VIEWABLE (parent))) &&
-          (parent == NULL ||
-           ! gimp_viewable_is_ancestor (GIMP_VIEWABLE (item),
-                                        GIMP_VIEWABLE (parent))))
+           (gimp_pdb_item_is_in_same_tree (item, parent, image, error) &&
+            gimp_pdb_item_is_group (parent, error) &&
+            gimp_pdb_item_is_not_ancestor (item, parent, error))))
         {
           success = gimp_image_reorder_item (image, item, parent, position,
                                              TRUE, NULL);
diff --git a/tools/pdbgen/pdb/image.pdb b/tools/pdbgen/pdb/image.pdb
index 8dbb515..730e0f7 100644
--- a/tools/pdbgen/pdb/image.pdb
+++ b/tools/pdbgen/pdb/image.pdb
@@ -903,14 +903,9 @@ HELP
 {
   if (gimp_pdb_item_is_in_tree (item, image, FALSE, error) &&
       (parent == NULL ||
-       gimp_pdb_item_is_in_tree (parent, image, FALSE, error)) &&
-      (parent == NULL ||
-       gimp_item_get_tree (item) == gimp_item_get_tree (parent)) &&
-      (parent == NULL ||
-       gimp_viewable_get_children (GIMP_VIEWABLE (parent))) &&
-      (parent == NULL ||
-       ! gimp_viewable_is_ancestor (GIMP_VIEWABLE (item),
-                                    GIMP_VIEWABLE (parent))))
+       (gimp_pdb_item_is_in_same_tree (item, parent, image, error) &&
+        gimp_pdb_item_is_group (parent, error) &&
+        gimp_pdb_item_is_not_ancestor (item, parent, error))))
     {
       success = gimp_image_reorder_item (image, item, parent, position,
                                          TRUE, NULL);