1 files changed, 95 insertions, 0 deletions

diff --git a/bitbake/lib/bb/asyncrpc/connection.py b/bitbake/lib/bb/asyncrpc/connection.py
new file mode 100644
index 0000000000..c4fd24754c
--- /dev/null
+++ b/bitbake/lib/bb/asyncrpc/connection.py
@@ -0,0 +1,95 @@
+#
+# Copyright BitBake Contributors
+#
+# SPDX-License-Identifier: GPL-2.0-only
+#
+
+import asyncio
+import itertools
+import json
+from .exceptions import ClientError, ConnectionClosedError
+
+
+# The Python async server defaults to a 64K receive buffer, so we hardcode our
+# maximum chunk size. It would be better if the client and server reported to
+# each other what the maximum chunk sizes were, but that will slow down the
+# connection setup with a round trip delay so I'd rather not do that unless it
+# is necessary
+DEFAULT_MAX_CHUNK = 32 * 1024
+
+
+def chunkify(msg, max_chunk):
+    if len(msg) < max_chunk - 1:
+        yield "".join((msg, "\n"))
+    else:
+        yield "".join((json.dumps({"chunk-stream": None}), "\n"))
+
+        args = [iter(msg)] * (max_chunk - 1)
+        for m in map("".join, itertools.zip_longest(*args, fillvalue="")):
+            yield "".join(itertools.chain(m, "\n"))
+        yield "\n"
+
+
+class StreamConnection(object):
+    def __init__(self, reader, writer, timeout, max_chunk=DEFAULT_MAX_CHUNK):
+        self.reader = reader
+        self.writer = writer
+        self.timeout = timeout
+        self.max_chunk = max_chunk
+
+    @property
+    def address(self):
+        return self.writer.get_extra_info("peername")
+
+    async def send_message(self, msg):
+        for c in chunkify(json.dumps(msg), self.max_chunk):
+            self.writer.write(c.encode("utf-8"))
+        await self.writer.drain()
+
+    async def recv_message(self):
+        l = await self.recv()
+
+        m = json.loads(l)
+        if not m:
+            return m
+
+        if "chunk-stream" in m:
+            lines = []
+            while True:
+                l = await self.recv()
+                if not l:
+                    break
+                lines.append(l)
+
+            m = json.loads("".join(lines))
+
+        return m
+
+    async def send(self, msg):
+        self.writer.write(("%s\n" % msg).encode("utf-8"))
+        await self.writer.drain()
+
+    async def recv(self):
+        if self.timeout < 0:
+            line = await self.reader.readline()
+        else:
+            try:
+                line = await asyncio.wait_for(self.reader.readline(), self.timeout)
+            except asyncio.TimeoutError:
+                raise ConnectionError("Timed out waiting for data")
+
+        if not line:
+            raise ConnectionClosedError("Connection closed")
+
+        line = line.decode("utf-8")
+
+        if not line.endswith("\n"):
+            raise ConnectionError("Bad message %r" % (line))
+
+        return line.rstrip()
+
+    async def close(self):
+        self.reader = None
+        if self.writer is not None:
+            self.writer.close()
+            self.writer = None