Refactor ArchiveRecreater.try_resume

src/borg/archive.py

@@ -1532,6 +1532,51 @@ def try_resume(self, archive, target_name):
         """Try to resume from temporary archive. Return (target archive, resume from path) if successful."""
         logger.info('Found %s, will resume interrupted operation', target_name)
         old_target = self.open_archive(target_name)
+        if not self.can_resume(archive, old_target, target_name):
+            return None, None
+        target = self.create_target_archive(target_name + '.temp')
+        logger.info('Replaying items from interrupted operation...')
+        last_old_item = self.copy_items(old_target, target)
+        if last_old_item:
+            resume_from = last_old_item.path
+        else:
+            resume_from = None
+        self.incref_partial_chunks(old_target, target)
+        old_target.delete(Statistics(), progress=self.progress)
+        logger.info('Done replaying items')
+        return target, resume_from
+
+    def incref_partial_chunks(self, source_archive, target_archive):
+        target_archive.recreate_partial_chunks = source_archive.metadata.get(b'recreate_partial_chunks', [])
+        for chunk_id, size, csize in target_archive.recreate_partial_chunks:
+            if not self.cache.seen_chunk(chunk_id):
+                try:
+                    # Repository has __contains__, RemoteRepository doesn't
+                    self.repository.get(chunk_id)
+                except Repository.ObjectNotFound:
+                    # delete/prune/check between invocations: these chunks are gone.
+                    target_archive.recreate_partial_chunks = None
+                    break
+                # fast-lane insert into chunks cache
+                self.cache.chunks[chunk_id] = (1, size, csize)
+                target_archive.stats.update(size, csize, True)
+                continue
+            # incref now, otherwise a source_archive.delete() might delete these chunks
+            self.cache.chunk_incref(chunk_id, target_archive.stats)
+
+    def copy_items(self, source_archive, target_archive):
+        item = None
+        for item in source_archive.iter_items():
+            if 'chunks' in item:
+                for chunk in item.chunks:
+                    self.cache.chunk_incref(chunk.id, target_archive.stats)
+                    target_archive.stats.nfiles += 1
+            target_archive.add_item(item)
+        if self.progress:
+            source_archive.stats.show_progress(final=True)  # XXX target_archive.stats?
+        return item
+
+    def can_resume(self, archive, old_target, target_name):
         resume_id = old_target.metadata[b'recreate_source_id']
         resume_args = [safe_decode(arg) for arg in old_target.metadata[b'recreate_args']]
         if resume_id != archive.id:
@@ -1539,45 +1584,13 @@ def try_resume(self, archive, target_name):
             logger.warning('Saved fingerprint:   %s', bin_to_hex(resume_id))
             logger.warning('Current fingerprint: %s', archive.fpr)
             old_target.delete(Statistics(), progress=self.progress)
-            return None, None  # can't resume
+            return False
         if resume_args != sys.argv[1:]:
             logger.warning('Command line changed, this might lead to inconsistencies')
             logger.warning('Saved:   %s', repr(resume_args))
             logger.warning('Current: %s', repr(sys.argv[1:]))
-        target = self.create_target_archive(target_name + '.temp')
+            # Just warn in this case, don't start over
-        logger.info('Replaying items from interrupted operation...')
+        return True
-        item = None
-        for item in old_target.iter_items():
-            if 'chunks' in item:
-                for chunk in item.chunks:
-                    self.cache.chunk_incref(chunk.id, target.stats)
-                target.stats.nfiles += 1
-            target.add_item(item)
-        if item:
-            resume_from = item.path
-        else:
-            resume_from = None
-        if self.progress:
-            old_target.stats.show_progress(final=True)
-        target.recreate_partial_chunks = old_target.metadata.get(b'recreate_partial_chunks', [])
-        for chunk_id, size, csize in target.recreate_partial_chunks:
-            if not self.cache.seen_chunk(chunk_id):
-                try:
-                    # Repository has __contains__, RemoteRepository doesn't
-                    self.repository.get(chunk_id)
-                except Repository.ObjectNotFound:
-                    # delete/prune/check between invocations: these chunks are gone.
-                    target.recreate_partial_chunks = None
-                    break
-                # fast-lane insert into chunks cache
-                self.cache.chunks[chunk_id] = (1, size, csize)
-                target.stats.update(size, csize, True)
-                continue
-            # incref now, otherwise old_target.delete() might delete these chunks
-            self.cache.chunk_incref(chunk_id, target.stats)
-        old_target.delete(Statistics(), progress=self.progress)
-        logger.info('Done replaying items')
-        return target, resume_from
 
     def create_target_archive(self, name):
         target = Archive(self.repository, self.key, self.manifest, name, create=True,