Copied read/write from secio

libp2p/security/noise/connection.py

@@ -1,3 +1,5 @@
+import io
+
 from noise.connection import NoiseConnection as NoiseState
 
 from libp2p.crypto.keys import PrivateKey
@@ -8,6 +10,10 @@ from libp2p.security.noise.io import MsgReadWriter, NoiseTransportReadWriter
 
 
 class NoiseConnection(BaseSession):
+    buf: io.BytesIO
+    low_watermark: int
+    high_watermark: int
+
     read_writer: IRawConnection
     noise_state: NoiseState
 
@@ -19,20 +25,64 @@ class NoiseConnection(BaseSession):
         conn: IRawConnection,
         is_initiator: bool,
         noise_state: NoiseState,
+        # remote_permanent_pubkey
     ) -> None:
         super().__init__(local_peer, local_private_key, is_initiator, remote_peer)
         self.conn = conn
         self.noise_state = noise_state
+        self._reset_internal_buffer()
 
     def get_msg_read_writer(self) -> MsgReadWriter:
         return NoiseTransportReadWriter(self.conn, self.noise_state)
 
+    async def close(self) -> None:
+        await self.conn.close()
+
+    def _reset_internal_buffer(self) -> None:
+        self.buf = io.BytesIO()
+        self.low_watermark = 0
+        self.high_watermark = 0
+
+    def _drain(self, n: int) -> bytes:
+        if self.low_watermark == self.high_watermark:
+            return bytes()
+
+        data = self.buf.getbuffer()[self.low_watermark : self.high_watermark]
+
+        if n is None:
+            n = len(data)
+        result = data[:n].tobytes()
+        self.low_watermark += len(result)
+
+        if self.low_watermark == self.high_watermark:
+            del data  # free the memoryview so we can free the underlying BytesIO
+            self.buf.close()
+            self._reset_internal_buffer()
+        return result
+
     async def read(self, n: int = None) -> bytes:
-        # TODO: Use a buffer to handle buffered messages.
+        if n == 0:
+            return bytes()
+
+        data_from_buffer = self._drain(n)
+        if len(data_from_buffer) > 0:
+            return data_from_buffer
+
+        msg = await self.read_msg()
+
+        if n < len(msg):
+            self.buf.write(msg)
+            self.low_watermark = 0
+            self.high_watermark = len(msg)
+            return self._drain(n)
+        else:
+            return msg
+
+    async def read_msg(self) -> bytes:
         return await self.get_msg_read_writer().read_msg()
 
     async def write(self, data: bytes) -> None:
-        await self.get_msg_read_writer().write_msg(data)
+        await self.write_msg(data)
 
-    async def close(self) -> None:
-        await self.conn.close()
+    async def write_msg(self, msg: bytes) -> None:
+        await self.get_msg_read_writer().write_msg(msg)

tests/security/noise/test_noise.py

@@ -3,7 +3,9 @@ import pytest
 from libp2p.security.noise.messages import NoiseHandshakePayload
 from libp2p.tools.factories import noise_conn_factory, noise_handshake_payload_factory
 
-DATA = b"testing_123"
+DATA_0 = b"data_0"
+DATA_1 = b"1" * 1000
+DATA_2 = b"data_2"
 
 
 @pytest.mark.trio
@@ -16,9 +18,12 @@ async def test_noise_transport(nursery):
 async def test_noise_connection(nursery):
     async with noise_conn_factory(nursery) as conns:
         local_conn, remote_conn = conns
-        await local_conn.write(DATA)
-        read_data = await remote_conn.read(len(DATA))
-        assert read_data == DATA
+        await local_conn.write(DATA_0)
+        await local_conn.write(DATA_1)
+        assert DATA_0 == (await remote_conn.read(len(DATA_0)))
+        assert DATA_1 == (await remote_conn.read(len(DATA_1)))
+        await local_conn.write(DATA_2)
+        assert DATA_2 == (await remote_conn.read(len(DATA_2)))
 
 
 def test_noise_handshake_payload():