From 3773681f00c030b0deff0c503d3d94577b9f32a6 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Antoine=20Beaupr=C3=A9?= <anarcat@koumbit.org>
Date: Sat, 3 Oct 2015 11:07:37 -0400
Subject: [PATCH] rewire cache copy mechanisms

we separate the conversion and the copy in order to be able to copy
arbitrary files from attic without converting them. this allows us to
copy the config file cleanly without attempting to rewrite its magic
number
---
 borg/converter.py | 56 +++++++++++++++++++++++++++++++++--------------
 1 file changed, 40 insertions(+), 16 deletions(-)

diff --git a/borg/converter.py b/borg/converter.py
index 7f4127cd8..39fe3788a 100644
--- a/borg/converter.py
+++ b/borg/converter.py
@@ -144,25 +144,49 @@ class AtticRepositoryConverter(Repository):
         # copy of attic's get_cache_dir()
         attic_cache_dir = os.environ.get('ATTIC_CACHE_DIR',
                           os.path.join(os.path.expanduser('~'), '.cache', 'attic'))
+        attic_cache_dir = os.path.join(attic_cache_dir, hexlify(self.id).decode('ascii'))
+        borg_cache_dir = os.path.join(get_cache_dir(), hexlify(self.id).decode('ascii'))
+
+        def copy_cache_file(file):
+            """copy the given attic cache file into the borg directory
+
+            does nothing if dryrun is True. also expects
+            attic_cache_dir and borg_cache_dir to be set in the parent
+            scope, to the directories path including the repository
+            identifier.
+
+            :params file: the basename of the cache file to copy
+            (example: "files" or "chunks") as a string
+
+            :returns: the borg file that was created or None if non
+            was created.
+
+            """
+            attic_file = os.path.join(attic_cache_dir, file)
+            if os.path.exists(attic_file):
+                borg_file = os.path.join(borg_cache_dir, file)
+                if os.path.exists(borg_file):
+                    print("borg cache file already exists in %s, skipping conversion of %s" % (borg_file, attic_file))
+                else:
+                    print("copying attic cache file from %s to %s" % (attic_file, borg_file))
+                    if not dryrun:
+                        shutil.copyfile(attic_file, borg_file)
+                    return borg_file
+            else:
+                print("no %s cache file found in %s" % (file, attic_file))
+            return None
+
+        if os.path.exists(attic_cache_dir):
+            if not os.path.exists(borg_cache_dir):
+                os.makedirs(borg_cache_dir)
+            copy_cache_file('config')
 
         # XXX: untested, because generating cache files is a PITA, see
         # Archiver.do_create() for proof
-        for cache in [ 'files', 'chunks', 'config' ]:
-            attic_cache = os.path.join(attic_cache_dir, hexlify(self.id).decode('ascii'), cache)
-            if os.path.exists(attic_cache):
-                borg_cache_dir = os.path.join(get_cache_dir(), hexlify(self.id).decode('ascii'))
-                if not os.path.exists(borg_cache_dir):
-                    os.makedirs(borg_cache_dir)
-                borg_cache = os.path.join(borg_cache_dir, cache)
-                if os.path.exists(borg_cache):
-                    print("borg cache already exists in %s, skipping conversion of %s" % (borg_cache, attic_cache))
-                else:
-                    print("copying attic cache from %s to %s" % (attic_cache, borg_cache))
-                    if not dryrun:
-                        shutil.copyfile(attic_cache, borg_cache)
-                    caches += [borg_cache]
-            else:
-                print("no %s cache found in %s" % (cache, attic_cache))
+        for cache in [ 'files', 'chunks' ]:
+            copied = copy_cache_file(cache)
+            if copied:
+                caches += [copied]
 
         for cache in caches:
             print("converting cache %s" % cache)