# HG changeset patch
# User Patrick Mezard <pmezard@gmail.com>
# Date 1306525810 -7200
# Node ID e763012a55e5680a91d7e3e7bd9a3c2a19cc4cfa
# Parent  9cb57d78b54f742336dd576a119ad9488aa8239d
patch: use temporary files to handle intermediate copies

git patches may require copies to be handled out-of-order. For instance, take
the following sequence:

  * modify a
  * copy a into b

Here, we have to generate b from a before its modification. To do so,
applydiff() was scanning for copy metadata and performing the copies before
processing the other changes in-order. While smart and efficient, this approach
complicates things by handling file copies and file creations at different
places and times. While a new file must not exist before being patched a copied
file already exists before applying the first hunk.

Instead of copying the files at their final destination before patching, we
store them in a temporary file location and retrieve them when patching. The
filestore always stores file content in real files but nothing prevents adding
a cache layer. The filestore class was kept separate from fsbackend for at
least two reasons:

- This class is likely to be reused as a temporary result store for a future
  repository patching call (entries just have to be extended to contain copy
  sources).

- Delegating this role to backends might be more efficient in a repository
  backend case: the source files are already available in the repository itself
  and do not need to be copied again. It also means that third-parties backend
  would have to implement two other methods. If we ever decide to merge the
  filestore feature into backend, a minimalistic approach would be to compose
  with filestore directly. Keep in mind this copy overhead only applies for
  copy/rename sources, and may even be reduced to copy sources which have to
  handled ahead of time.

[ original upstream message ]

diff -r 9cb57d78b54f -r e763012a55e5 hgkw/keyword.py
--- a/hgkw/keyword.py	Fri May 27 21:50:09 2011 +0200
+++ b/hgkw/keyword.py	Fri May 27 21:50:10 2011 +0200
@@ -595,11 +595,12 @@
                 wlock.release()
 
     # monkeypatches
-    def kwpatchfile_init(orig, self, ui, fname, backend, mode, create, remove,
-                         missing=False, eolmode=None):
+    def kwpatchfile_init(orig, self, ui, fname, backend, store, mode, create,
+                         remove, eolmode=None, copysource=None):
         '''Monkeypatch/wrap patch.patchfile.__init__ to avoid
         rejects or conflicts due to expanded keywords in working dir.'''
-        orig(self, ui, fname, backend, mode, create, remove, missing, eolmode)
+        orig(self, ui, fname, backend, store, mode, create, remove,
+             eolmode, copysource)
         # shrink keywords read from working dir
         self.lines = kwt.shrinklines(self.fname, self.lines)