[PATCH v3] Fix O(n) runtime in cache lookup, part 2/2

[Stefan Fuhrmann <st...@alice-dsl.de>]

Hi there,

this is a revised version of the patch posted here:
http://svn.haxx.se/dev/archive-2010-04/0107.shtml

Changes:

* use the new svn_cache__set_pinned function
* remove other changes that accidentally got added
  to the patch

-- Stefan^2.

[[[
Allow for cache entries to be access directly, i.e. without
prior copying. Use that to fix FSFS directory traversal
runtime from O(N^2) to O(n).

* subversion/libsvn_fs_fs/dag.c
  (dir_entry_id_from_node): call the new, efficient
  lookup function.
  (svn_fs_fs__dag_dir_entry): implement the new
  lookup function
  (svn_fs_fs__dag_dir_entries, svn_fs_fs__dag_delete):
  adapt to svn_fs_fs__rep_contents_dir signature change

* subversion/libsvn_fs_fs/dag.h
  (svn_fs_fs__dag_dir_entry): declare new function

* subversion/libsvn_fs_fs/fs_fs.c
  (svn_fs_fs__rep_contents_dir): add support for optionally
  returning a pinned cache reference instead of a copy.
  (svn_fs_fs__set_entry, write_final_rev): adapt to
  svn_fs_fs__rep_contents_dir signature change

* subversion/libsvn_fs_fs/fs_fs.h
  (svn_fs_fs__rep_contents_dir): add pin parameter

patch by stefanfuhrmann < at > alice-dsl.de
]]]