[merge] LockDir: use put_file_non_atomic instead of append_file

[Martin Pool]

On  8 Sep 2006, John Arbash Meinel <john at arbash-meinel.com> wrote:
> The attached bundle just changes LockDir to use the new
> 'put_file_non_atomic()' since it saves an extra round trip with sftp.
> 
> When locking a remote directory, this saves a round trip for each lock.
> So in the common case, this saves 2 round trips. (For me, this is 200+ms
> when committing or pushing to Launchpad).

Because we don't need to stat the file to tell how long it will be?

+1
> === modified file bzrlib/lockdir.py
> --- bzrlib/lockdir.py
> +++ bzrlib/lockdir.py
> @@ -203,11 +203,11 @@
>              sio = StringIO()
>              self._prepare_info(sio)
>              sio.seek(0)
> -            # append will create a new file; we use append rather than put
> -            # because we don't want to write to a temporary file and rename
> -            # into place, because that's going to happen to the whole
> -            # directory
> -            self.transport.append_file(tmpname + self.__INFO_NAME, sio)
> +            # We use put_file_non_atomic because we just created a new unique
> +            # directory so we don't have to worry about files existing there.
> +            # We'll rename the whole directory into place to get atomic
> +            # properties
> +            self.transport.put_file_non_atomic(tmpname + self.__INFO_NAME, sio)
>  
>              self.transport.rename(tmpname, self._held_dir)
>              self._lock_held = True

Presumably this could use put_bytes_non_atomic to be a bit simpler?

-- 
Martin