From 36b7e8ded96cd4aaab7b0666382dc304d93019f3 Mon Sep 17 00:00:00 2001
From: Chih Cheng Liang <chihchengliang@gmail.com>
Date: Fri, 2 Aug 2019 17:14:43 +0800
Subject: [PATCH] Refactor HeaderTags

---
 libp2p/stream_muxer/mplex/constants.py    | 12 +++++++++++-
 libp2p/stream_muxer/mplex/mplex.py        | 13 +++++++------
 libp2p/stream_muxer/mplex/mplex_stream.py | 19 +++++++++++++------
 libp2p/stream_muxer/mplex/utils.py        | 14 --------------
 4 files changed, 31 insertions(+), 27 deletions(-)

diff --git a/libp2p/stream_muxer/mplex/constants.py b/libp2p/stream_muxer/mplex/constants.py
index a0537b2..8989e76 100644
--- a/libp2p/stream_muxer/mplex/constants.py
+++ b/libp2p/stream_muxer/mplex/constants.py
@@ -1 +1,11 @@
-HEADER_TAGS = {"NEW_STREAM": 0, "MESSAGE": 2, "CLOSE": 4, "RESET": 6}
+from enum import Enum
+
+
+class HeaderTags(Enum):
+    NewStream = 0
+    MessageReceiver = 1
+    MessageInitiator = 2
+    CloseReceiver = 3
+    CloseInitiator = 4
+    ResetReceiver = 5
+    ResetInitiator = 6
diff --git a/libp2p/stream_muxer/mplex/mplex.py b/libp2p/stream_muxer/mplex/mplex.py
index f00588b..08970ff 100644
--- a/libp2p/stream_muxer/mplex/mplex.py
+++ b/libp2p/stream_muxer/mplex/mplex.py
@@ -1,8 +1,9 @@
 import asyncio
 
-from ..muxed_connection_interface import IMuxedConn
+from .constants import HeaderTags
+from .utils import encode_uvarint, decode_uvarint_from_stream
 from .mplex_stream import MplexStream
-from .utils import decode_uvarint_from_stream, encode_uvarint, get_flag
+from ..muxed_connection_interface import IMuxedConn
 
 
 class Mplex(IMuxedConn):
@@ -78,7 +79,7 @@ class Mplex(IMuxedConn):
         stream_id = self.raw_conn.next_stream_id()
         stream = MplexStream(stream_id, multi_addr, self)
         self.buffers[stream_id] = asyncio.Queue()
-        await self.send_message(get_flag(self.initiator, "NEW_STREAM"), None, stream_id)
+        await self.send_message(HeaderTags.NewStream, None, stream_id)
         return stream
 
     async def accept_stream(self):
@@ -90,7 +91,7 @@ class Mplex(IMuxedConn):
         stream = MplexStream(stream_id, False, self)
         asyncio.ensure_future(self.generic_protocol_handler(stream))
 
-    async def send_message(self, flag, data, stream_id):
+    async def send_message(self, flag: HeaderTags, data, stream_id):
         """
         sends a message over the connection
         :param header: header to use
@@ -99,7 +100,7 @@ class Mplex(IMuxedConn):
         :return: True if success
         """
         # << by 3, then or with flag
-        header = (stream_id << 3) | flag
+        header = (stream_id << 3) | flag.value
         header = encode_uvarint(header)
 
         if data is None:
@@ -135,7 +136,7 @@ class Mplex(IMuxedConn):
                     self.buffers[stream_id] = asyncio.Queue()
                     await self.stream_queue.put(stream_id)
 
-                if flag is get_flag(True, "NEW_STREAM"):
+                if flag == HeaderTags.NewStream.value:
                     # new stream detected on connection
                     await self.accept_stream()
 
diff --git a/libp2p/stream_muxer/mplex/mplex_stream.py b/libp2p/stream_muxer/mplex/mplex_stream.py
index a1a25b7..e452fbd 100644
--- a/libp2p/stream_muxer/mplex/mplex_stream.py
+++ b/libp2p/stream_muxer/mplex/mplex_stream.py
@@ -2,7 +2,7 @@ import asyncio
 
 from libp2p.stream_muxer.muxed_stream_interface import IMuxedStream
 
-from .utils import get_flag
+from .constants import HeaderTags
 
 
 class MplexStream(IMuxedStream):
@@ -38,9 +38,12 @@ class MplexStream(IMuxedStream):
         write to stream
         :return: number of bytes written
         """
-        return await self.mplex_conn.send_message(
-            get_flag(self.initiator, "MESSAGE"), data, self.stream_id
+        flag = (
+            HeaderTags.MessageInitiator
+            if self.initiator
+            else HeaderTags.MessageReceiver
         )
+        return await self.mplex_conn.send_message(flag, data, self.stream_id)
 
     async def close(self):
         """
@@ -50,7 +53,8 @@ class MplexStream(IMuxedStream):
         """
         # TODO error handling with timeout
         # TODO understand better how mutexes are used from go repo
-        await self.mplex_conn.send_message(get_flag(self.initiator, "CLOSE"), None, self.stream_id)
+        flag = HeaderTags.CloseInitiator if self.initiator else HeaderTags.CloseReceiver
+        await self.mplex_conn.send_message(flag, None, self.stream_id)
 
         remote_lock = ""
         async with self.stream_lock:
@@ -78,9 +82,12 @@ class MplexStream(IMuxedStream):
                 return True
 
             if not self.remote_closed:
-                await self.mplex_conn.send_message(
-                    get_flag(self.initiator, "RESET"), None, self.stream_id
+                flag = (
+                    HeaderTags.ResetInitiator
+                    if self.initiator
+                    else HeaderTags.ResetInitiator
                 )
+                await self.mplex_conn.send_message(flag, None, self.stream_id)
 
             self.local_closed = True
             self.remote_closed = True
diff --git a/libp2p/stream_muxer/mplex/utils.py b/libp2p/stream_muxer/mplex/utils.py
index 70dcd12..7bd5772 100644
--- a/libp2p/stream_muxer/mplex/utils.py
+++ b/libp2p/stream_muxer/mplex/utils.py
@@ -1,8 +1,6 @@
 import asyncio
 import struct
 
-from .constants import HEADER_TAGS
-
 
 def encode_uvarint(number):
     """Pack `number` into varint bytes"""
@@ -44,15 +42,3 @@ async def decode_uvarint_from_stream(reader, timeout):
             break
 
     return result
-
-
-def get_flag(initiator, action):
-    """
-    get header flag based on action for mplex
-    :param action: action type in str
-    :return: int flag
-    """
-    if initiator or HEADER_TAGS[action] == 0:
-        return HEADER_TAGS[action]
-
-    return HEADER_TAGS[action] - 1