# 
# patch "commands.cc"
#  from [af9078ec98297982cd41e7a8b0cea758e9a9df6c]
#    to [7a5a8d34d167ffb077abf385ff687b3018327543]
# 
# patch "cset.hh"
#  from [37e25c0a3768be89b4a6208db27ebdfc5cf1968f]
#    to [1d39340bb52aef571e199835e698586da071aa66]
# 
# patch "roster.hh"
#  from [fbb120910384d9f860cb39b2f576e470c9187c46]
#    to [36aa7d8540e15710ea9fb44023c7e0419fdf4c1b]
# 
# patch "work.cc"
#  from [0dcca2bd49850d419b5904775a74313235fcba2a]
#    to [5157509316effe608f2939ffda66714edb6b2a71]
# 
# patch "work.hh"
#  from [3fe7ca77fa62c1c922143e00f3a708b62627d891]
#    to [5690b5fbbff1b09efb707af80ba8b4f84c0288cf]
# 
========================================================================
--- commands.cc	af9078ec98297982cd41e7a8b0cea758e9a9df6c
+++ commands.cc	7a5a8d34d167ffb077abf385ff687b3018327543
@@ -2611,7 +2611,7 @@
     }
 }
 
-  /*
+  /* FIXME_ROSTERS
 
 CMD(diff, N_("informative"), N_("[PATH]..."), 
     N_("show current diffs on stdout.\n"
========================================================================
--- cset.hh	37e25c0a3768be89b4a6208db27ebdfc5cf1968f
+++ cset.hh	1d39340bb52aef571e199835e698586da071aa66
@@ -31,12 +31,12 @@
 {
   // Detaching existing nodes (for renaming or deleting)
   virtual node_id detach_node(split_path const & src) = 0;
-  virtual void drop_detached_node(node_id n) = 0;
+  virtual void drop_detached_node(node_id nid) = 0;
 
   // Attaching new nodes (via creation or as the tail end of renaming)
   virtual node_id create_dir_node() = 0;
   virtual node_id create_file_node(file_id const & content) = 0;
-  virtual void attach_node(node_id n, split_path const & dst) = 0;
+  virtual void attach_node(node_id nid, split_path const & dst) = 0;
 
   // Modifying elements in-place
   virtual void apply_delta(split_path const & pth, 
========================================================================
--- roster.hh	fbb120910384d9f860cb39b2f576e470c9187c46
+++ roster.hh	36aa7d8540e15710ea9fb44023c7e0419fdf4c1b
@@ -166,15 +166,15 @@
   roster_t & operator=(roster_t const & other);
   bool has_root() const;
   bool has_node(split_path const & sp) const;
-  bool has_node(node_id n) const;
+  bool has_node(node_id nid) const;
   node_t get_node(split_path const & sp) const;
-  node_t get_node(node_id n) const;
-  void get_name(node_id n, split_path & sp) const;
+  node_t get_node(node_id nid) const;
+  void get_name(node_id nid, split_path & sp) const;
   void replace_node_id(node_id from, node_id to);
 
   // editable_tree operations
   node_id detach_node(split_path const & src);
-  void drop_detached_node(node_id n);
+  void drop_detached_node(node_id nid);
   node_id create_dir_node(node_id_source & nis);
   void create_dir_node(node_id nid);
   node_id create_file_node(file_id const & content,
@@ -182,8 +182,8 @@
   void create_file_node(file_id const & content,
                         node_id nid);
   void insert_node(node_t n);
-  void attach_node(node_id n, split_path const & dst);
-  void attach_node(node_id n, node_id parent, path_component name);
+  void attach_node(node_id nid, split_path const & dst);
+  void attach_node(node_id nid, node_id parent, path_component name);
   void apply_delta(split_path const & pth, 
                    file_id const & old_id, 
                    file_id const & new_new);
@@ -278,10 +278,10 @@
 
 void
 select_nodes_modified_by_cset(cset const & cs,
-			      roster_t const & old_roster,
-			      roster_t const & new_roster,
-			      std::set<node_id> & nodes_changed,
-			      std::set<node_id> & nodes_born);
+                              roster_t const & old_roster,
+                              roster_t const & new_roster,
+                              std::set<node_id> & nodes_changed,
+                              std::set<node_id> & nodes_born);
 
 void 
 update_restricted_roster_from_filesystem(roster_t & ros, 
========================================================================
--- work.cc	0dcca2bd49850d419b5904775a74313235fcba2a
+++ work.cc	5157509316effe608f2939ffda66714edb6b2a71
@@ -781,3 +781,108 @@
   apply_attributes(app, attr);
 */
 }
+
+editable_working_tree::editable_working_tree(app_state & app,
+                                             file_content_source const & source)
+  : app(app), source(source), next_nid(1)
+{
+}
+
+static inline bookkeeping_path
+path_for_nid(node_id nid)
+{
+  return bookkeeping_root / "tmp" / boost::lexical_cast<std::string>(nid);
+}
+
+node_id
+editable_working_tree::detach_node(split_path const & src)
+{
+  node_id nid = next_nid++;
+  file_path src_pth(src);
+  bookkeeping_path dst_pth = path_for_nid(nid);
+  make_dir_for(dst_pth);
+  move_path(src_pth, dst_pth);
+  return nid;
+}
+
+void
+editable_working_tree::drop_detached_node(node_id nid)
+{
+  bookkeeping_path pth = path_for_nid(nid);
+  delete_file_or_dir_shallow(pth);
+}
+
+node_id
+editable_working_tree::create_dir_node()
+{
+  node_id nid = next_nid++;
+  bookkeeping_path pth = path_for_nid(nid);
+  require_path_is_nonexistent(pth,
+                              F("path %s already exists"));
+  mkdir_p(pth);
+  return nid;
+}
+
+node_id
+editable_working_tree::create_file_node(file_id const & content)
+{
+  node_id nid = next_nid++;
+  bookkeeping_path pth = path_for_nid(nid);
+  require_path_is_nonexistent(pth,
+                              F("path %s already exists"));
+  file_data dat;
+  source.get_file_content(content, dat);
+  // FIXME_ROSTERS: what about charset conversion etc.?
+  write_data(pth, dat.inner());
+  return nid;
+}
+
+void
+editable_working_tree::attach_node(node_id nid, split_path const & dst)
+{
+  bookkeeping_path src_pth = path_for_nid(nid);
+  file_path dst_pth(dst);
+  move_path(src_pth, dst_pth);
+}
+
+void
+editable_working_tree::apply_delta(split_path const & pth, 
+                                   file_id const & old_id, 
+                                   file_id const & new_id)
+{
+  file_path pth_unsplit(pth);
+  require_path_is_file(pth_unsplit,
+                       F("file '%s' does not exist") % pth_unsplit,
+                       F("file '%s' is a directory") % pth_unsplit);
+  hexenc<id> curr_id_raw;
+  calculate_ident(pth_unsplit, curr_id_raw, app.lua);
+  file_id curr_id(curr_id_raw);
+  E(curr_id == old_id,
+    F("content of file '%s' has changed, not overwriting"));
+  P(F("updating %s to %s") % pth_unsplit % new_id);
+
+  file_data dat;
+  source.get_file_content(new_id, dat);
+  // FIXME_ROSTERS: inconsistent with file addition code above, and
+  // write_localized_data is poorly designed anyway...
+  write_localized_data(pth_unsplit, dat.inner(), app.lua);
+}
+
+void
+editable_working_tree::clear_attr(split_path const & pth,
+                                  attr_key const & name)
+{
+  // FIXME_ROSTERS: call a lua hook
+}
+
+void
+editable_working_tree::set_attr(split_path const & pth,
+                                attr_key const & name,
+                                attr_value const & val)
+{
+  // FIXME_ROSTERS: call a lua hook
+}
+
+editable_working_tree::~editable_working_tree()
+{
+}
========================================================================
--- work.hh	3fe7ca77fa62c1c922143e00f3a708b62627d891
+++ work.hh	5690b5fbbff1b09efb707af80ba8b4f84c0288cf
@@ -207,4 +207,38 @@
 extern std::string const binary_encoding;
 extern std::string const default_encoding;
 
+struct file_content_source
+{
+  virtual void get_file_content(file_id const & fid,
+                                file_data const & dat) const = 0;
+  virtual ~file_content_source() {};
+};
+
+struct editable_working_tree : public editable_tree
+{
+  editable_working_tree(app_state & app, file_content_source const & source);
+
+  virtual node_id detach_node(split_path const & src);
+  virtual void drop_detached_node(node_id nid);
+
+  virtual node_id create_dir_node();
+  virtual node_id create_file_node(file_id const & content);
+  virtual void attach_node(node_id nid, split_path const & dst);
+
+  virtual void apply_delta(split_path const & pth, 
+                           file_id const & old_id, 
+                           file_id const & new_id);
+  virtual void clear_attr(split_path const & pth,
+                          attr_key const & name);
+  virtual void set_attr(split_path const & pth,
+                        attr_key const & name,
+                        attr_value const & val);
+
+  virtual ~editable_working_tree();
+private:
+  app_state & app;
+  file_content_source const & source;
+  node_id next_nid;
+};
+
 #endif // __WORK_HH__