[meld] dirdiff: Refactor sibling revalidating logic

[Kai Willadsen <kaiw src gnome org>]

commit ae1e5497c6016e0da6bf8e67c1a70a60e057c0a2
Author: Kai Willadsen <kai willadsen gmail com>
Date:   Sun Jan 12 08:31:07 2014 +1000

    dirdiff: Refactor sibling revalidating logic

 meld/dirdiff.py |   23 ++++++++++-------------
 meld/tree.py    |    5 +++++
 2 files changed, 15 insertions(+), 13 deletions(-)
---
diff --git a/meld/dirdiff.py b/meld/dirdiff.py
index a83249f..7a7c84a 100644
--- a/meld/dirdiff.py
+++ b/meld/dirdiff.py
@@ -827,19 +827,16 @@ class DirDiff(melddoc.MeldDoc, gnomeglade.Component):
                             # if parent has more children: state of these children is in state_filters;
                             # parent may not be removed in this case : stop while loop
                         else:
-                            self.model.remove(it)   # all paths of sibling dirs still on the stack are now 
invalid!
-                            index = 0
-                            # siblings that are on the stack, all occupy the top positions (in reverse order)
-                            while it is not None:
-                                one_dir = any(os.path.isdir(f) for f in self.model.value_paths(it))
-                                if one_dir:
-                                    index += 1
-                                    todo[-index] = self.model.get_path(it)   # correct the path for this 
sibling
-                                else:
-                                    # stop while loop: it == sibling files and sibling dirs come first in 
tree
-                                    break
-                                it = self.model.iter_next(it)
-                            break   # parent of current level in tree has children : stop while loop
+                            # Remove the current row, and then revalidate all
+                            # sibling paths on the stack by removing and
+                            # readding them
+                            deleted_path = self.model.get_path(it)
+                            self.model.remove(it)
+                            for path in todo:
+                                if tree.path_is_sibling(path, deleted_path):
+                                    path.prev()
+                            # parent of current level in tree has children : stop while loop
+                            break
 
             if differences:
                 expanded.add(path)
diff --git a/meld/tree.py b/meld/tree.py
index 98a1048..3d5287d 100644
--- a/meld/tree.py
+++ b/meld/tree.py
@@ -35,6 +35,11 @@ from meld.vc._vc import \
     CONFLICT_MERGED, CONFLICT_OTHER, CONFLICT_THIS
 
 
+def path_is_sibling(path1, path2):
+    return (len(path1) == len(path2) and
+            path1.get_indices()[:-1] == path2.get_indices()[:-1])
+
+
 class DiffTreeStore(Gtk.TreeStore):
 
     def __init__(self, ntree, types):