Don't compute whole-file MD5 unless allowed

2 files changed, 15 insertions, 6 deletions

diff --git a/obnamlib/plugins/backup_plugin.py b/obnamlib/plugins/backup_plugin.py
index 88134a2d..7e0f771e 100644
--- a/obnamlib/plugins/backup_plugin.py
+++ b/obnamlib/plugins/backup_plugin.py
@@ -727,7 +727,10 @@ class BackupPlugin(obnamlib.ObnamPlugin):
         tracing.trace('opening file for reading')
         f = self.fs.open(filename, 'r')
 
-        summer = hashlib.md5()
+        if obnamlib.REPO_FILE_MD5 in self.repo.get_allowed_file_keys():
+            summer = hashlib.md5()
+        else:
+            summer = None
 
         chunk_size = int(self.app.settings['chunk-size'])
         while True:
@@ -739,7 +742,8 @@ class BackupPlugin(obnamlib.ObnamPlugin):
                 break
             tracing.trace('got %d bytes of data' % len(data))
             self.progress.update_progress_with_scanned(len(data))
-            summer.update(data)
+            if summer:
+                summer.update(data)
             if not self.pretend:
                 chunk_id = self.backup_file_chunk(data)
                 self.repo.append_file_chunk_id(
@@ -758,7 +762,8 @@ class BackupPlugin(obnamlib.ObnamPlugin):
         self.app.dump_memory_profile('at end of file content backup for %s' %
                                      filename)
         tracing.trace('done backing up file contents')
-        metadata.md5 = summer.digest()
+        if summer:
+            metadata.md5 = summer.digest()
 
     def backup_file_chunk(self, data):
         '''Back up a chunk of data by putting it into the repository.'''
diff --git a/obnamlib/plugins/restore_plugin.py b/obnamlib/plugins/restore_plugin.py
index 239eef45..f24ac491 100644
--- a/obnamlib/plugins/restore_plugin.py
+++ b/obnamlib/plugins/restore_plugin.py
@@ -274,7 +274,10 @@ class RestorePlugin(obnamlib.ObnamPlugin):
         logging.debug('restoring regular %s', filename)
         if self.write_ok:
             f = self.fs.open('./' + filename, 'wb')
-            summer = hashlib.md5()
+            if obnamlib.REPO_FILE_MD5 in self.repo.get_allowed_file_keys():
+                summer = hashlib.md5()
+            else:
+                summer = None
 
             try:
                 chunkids = self.repo.get_file_chunk_ids(gen, filename)
@@ -287,7 +290,7 @@ class RestorePlugin(obnamlib.ObnamPlugin):
             f.close()
 
             correct_checksum = metadata.md5
-            if summer.digest() != correct_checksum:
+            if summer and summer.digest() != correct_checksum:
                 msg = 'File checksum restore error: %s' % filename
                 msg += ' (%s vs %s)' % (
                     summer.hexdigest(), correct_checksum.encode('hex'))
@@ -301,7 +304,8 @@ class RestorePlugin(obnamlib.ObnamPlugin):
         for chunkid in chunkids:
             data = self.repo.get_chunk_content(chunkid)
             self.verify_chunk_checksum(data, chunkid)
-            checksummer.update(data)
+            if checksummer:
+                checksummer.update(data)
             self.downloaded_bytes += len(data)
             if len(data) != len(zeroes):
                 zeroes = '\0' * len(data)