# 
# 
# patch "file_io.cc"
#  from [3214c2cad3ec630d8466926bd4bae693de9184a0]
#    to [6c9c825346a1256c0e83b52302512ea39e1687b8]
# 
# patch "file_io.hh"
#  from [2082dc3c8480400f32fcbe1c4d881d7512de2204]
#    to [0ad781436181e45effc327ca11ab7647ca8b2e9e]
# 
# patch "work.cc"
#  from [39e5c9ecd7f5209dbcbb7e631d6fc044296a4a67]
#    to [d0ac482a5c29fe016912f98c89ae141f3c04a322]
# 
# patch "work.hh"
#  from [2e87d93b08c16ef877483f69594636c480d0f97f]
#    to [394cfb37fa7d52006048ccf4f88059f18ec74d1c]
# 
============================================================
--- file_io.cc	3214c2cad3ec630d8466926bd4bae693de9184a0
+++ file_io.cc	6c9c825346a1256c0e83b52302512ea39e1687b8
@@ -484,8 +484,6 @@
 {
   write_data_impl(path, data, tmpdir / (boost::format("data.tmp.%d") %
                                              get_process_id()).str());
-
-
 }
 
 tree_walker::~tree_walker() {}
@@ -533,8 +531,8 @@
             }
           if (fs::is_directory(entry))
             {
-              walker.visit_dir(p);
-              walk_tree_recursive(entry, rel_entry, walker);
+              if (walker.visit_dir(p))
+                walk_tree_recursive(entry, rel_entry, walker);
             }
           else
             {
@@ -545,9 +543,10 @@
     }
 }
 
-void
+bool
 tree_walker::visit_dir(file_path const & path)
 {
+  return true;
 }
 
 
@@ -573,10 +572,10 @@
       walker.visit_file(path);
       break;
     case path::directory:
-      walker.visit_dir(path);
-      walk_tree_recursive(system_path(path).as_external(),
-                          path.as_external(),
-                          walker);
+      if (walker.visit_dir(path))
+        walk_tree_recursive(system_path(path).as_external(),
+                            path.as_external(),
+                            walker);
       break;
     }
 }
============================================================
--- file_io.hh	2082dc3c8480400f32fcbe1c4d881d7512de2204
+++ file_io.hh	0ad781436181e45effc327ca11ab7647ca8b2e9e
@@ -101,7 +101,8 @@
 class tree_walker
 {
 public:
-  virtual void visit_dir(file_path const & path);
+  // returns true if the directory should be descended into
+  virtual bool visit_dir(file_path const & path);
   virtual void visit_file(file_path const & path) = 0;
   virtual ~tree_walker();
 };
============================================================
--- work.cc	39e5c9ecd7f5209dbcbb7e631d6fc044296a4a67
+++ work.cc	d0ac482a5c29fe016912f98c89ae141f3c04a322
@@ -28,10 +28,11 @@
 
 string const attr_file_name(".mt-attrs");
 
-void 
+bool
 file_itemizer::visit_dir(file_path const & path)
 {
   this->visit_file(path);
+  return true;
 }
 
 void 
@@ -347,7 +348,35 @@
   update_any_attrs(app);
 }
 
+void
+perform_pivot_root(file_path const & new_root, file_path const & put_old,
+                   app_state & app)
+{
+split_path new_root_sp, put_old_sp, root_sp;
+  new_root.split(new_root_sp);
+  put_old.split(put_old_sp);
+  file_path().split(root_sp);
 
+  temp_node_id_source nis;
+  roster_t base_roster, new_roster;
+  get_base_and_current_roster_shape(base_roster, new_roster, nis, app);
+
+  I(new_roster.has_root());
+  N(new_roster.has_node(new_root_sp),
+    F("proposed new root directory '%s' is not versioned or does not exist") % new_root);
+  {
+    split_path new_root_MT;
+    (new_root / bookkeeping_root).split(new_root_MT);
+    N(!new_roster.has_node(new_root_MT),
+      F("proposed new root directory '%s' contains illegal path %s") % new_root % bookkeeping_root);
+  }
+
+  node_id old_root_nid = new_roster.detach_node(root_sp);
+  node_id new_root_nid = new_roster.detach_node(new_root_sp);
+  new_roster.attach_node(new_root_nid, root_sp);
+}
+
+
 // work file containing rearrangement from uncommitted adds/drops/renames
 
 std::string const work_file_name("work");
============================================================
--- work.hh	2e87d93b08c16ef877483f69594636c480d0f97f
+++ work.hh	394cfb37fa7d52006048ccf4f88059f18ec74d1c
@@ -55,7 +55,7 @@
   path_set & ignored;
   file_itemizer(app_state & a, path_set & k, path_set & u, path_set & i) 
     : app(a), known(k), unknown(u), ignored(i) {}
-  virtual void visit_dir(file_path const & path);
+  virtual bool visit_dir(file_path const & path);
   virtual void visit_file(file_path const & path);
 };
 
@@ -70,6 +70,10 @@
                file_path const & dst_dir,
                app_state & app);
 
+void
+perform_pivot_root(file_path const & new_root, file_path const & put_old,
+                   app_state & app);
+
 // the "work" file contains the current cset representing uncommitted
 // add/drop/rename operations (not deltas)