[Lint] Use Black to auto-format code

The move to using auto-formatter makes it easier to read, submit and
speeds up development time. https://github.com/ambv/black/

Although I would prefer 79 chars, the default line length of 88 chars
used by black suffices. The flake8 line length remains at 120 chars
since black does not touch comments or docstrings and this will require
another round of fixes.

The only black setting that is not standard is the use of double-quotes
for strings so disabled any formatting of these. Note however that
flake8 will still flag usage of double-quotes. I may change my mind on
double vs single quotes but for now leave them.

A new pyproject.toml file has been created for black configuration.

1 files changed, 17 insertions, 6 deletions

diff --git a/deluge/transfer.py b/deluge/transfer.py
index c1859eb67..85274d46c 100644
--- a/deluge/transfer.py
+++ b/deluge/transfer.py
@@ -32,6 +32,7 @@ class DelugeTransferProtocol(Protocol, object):
     the length of the data to be transfered (payload).
 
     """
+
     def __init__(self):
         self._buffer = b''  # TODO: Look into using bytearray instead of byte string.
         self._message_length = 0
@@ -78,9 +79,9 @@ class DelugeTransferProtocol(Protocol, object):
                 self._handle_new_message()
             # We have a complete packet
             if len(self._buffer) >= self._message_length:
-                self._handle_complete_message(self._buffer[:self._message_length])
+                self._handle_complete_message(self._buffer[: self._message_length])
                 # Remove message data from buffer
-                self._buffer = self._buffer[self._message_length:]
+                self._buffer = self._buffer[self._message_length :]
                 self._message_length = 0
             else:
                 break
@@ -96,7 +97,9 @@ class DelugeTransferProtocol(Protocol, object):
             header = self._buffer[:MESSAGE_HEADER_SIZE]
             payload_len = header[1:MESSAGE_HEADER_SIZE]
             if header[0:1] != b'D':
-                raise Exception('Invalid header format. First byte is %d' % ord(header[0:1]))
+                raise Exception(
+                    'Invalid header format. First byte is %d' % ord(header[0:1])
+                )
             # Extract the length stored as a signed integer (using 4 bytes)
             self._message_length = struct.unpack('!i', payload_len)[0]
             if self._message_length < 0:
@@ -105,7 +108,9 @@ class DelugeTransferProtocol(Protocol, object):
             self._buffer = self._buffer[MESSAGE_HEADER_SIZE:]
         except Exception as ex:
             log.warning('Error occurred when parsing message header: %s.', ex)
-            log.warning('This version of Deluge cannot communicate with the sender of this data.')
+            log.warning(
+                'This version of Deluge cannot communicate with the sender of this data.'
+            )
             self._message_length = 0
             self._buffer = b''
 
@@ -117,9 +122,15 @@ class DelugeTransferProtocol(Protocol, object):
 
         """
         try:
-            self.message_received(rencode.loads(zlib.decompress(data), decode_utf8=True))
+            self.message_received(
+                rencode.loads(zlib.decompress(data), decode_utf8=True)
+            )
         except Exception as ex:
-            log.warning('Failed to decompress (%d bytes) and load serialized data with rencode: %s', len(data), ex)
+            log.warning(
+                'Failed to decompress (%d bytes) and load serialized data with rencode: %s',
+                len(data),
+                ex,
+            )
 
     def get_bytes_recv(self):
         """