feat: improve performance of reading from the socket during unmarshall (#200)

.github/workflows/ci.yml

@@ -65,7 +65,7 @@ jobs:
           if [ "${{ matrix.extension }}" = "skip_cython" ]; then
             SKIP_CYTHON=1 poetry install --only=main,dev
           else
-            poetry install --only=main,dev
+            REQUIRE_CYTHON=1 poetry install --only=main,dev
           fi
       - name: Test with Pytest
         run: export $(dbus-launch); poetry run pytest --cov-report=xml --timeout=5

src/dbus_fast/_private/unmarshaller.pxd

@@ -123,6 +123,7 @@ cdef class Unmarshaller:
 
     @cython.locals(
         msg=cython.bytes,
+        recv=cython.tuple
     )
     cdef bytes _read_sock(self, object length)
 

src/dbus_fast/_private/unmarshaller.py

@@ -250,13 +250,16 @@ class Unmarshaller:
         from the read itself"""
         # This will raise BlockingIOError if there is no data to read
         # which we store in the MARSHALL_STREAM_END_ERROR object
-        msg, ancdata, _flags, _addr = self._sock.recvmsg(length, UNIX_FDS_CMSG_LENGTH)  # type: ignore[union-attr]
-        for level, type_, data in ancdata:
-            if not (level == SOL_SOCKET and type_ == SCM_RIGHTS):
-                continue
-            self._unix_fds.extend(
-                ARRAY("i", data[: len(data) - (len(data) % MAX_UNIX_FDS_SIZE)])
-            )
+        recv = self._sock.recvmsg(length, UNIX_FDS_CMSG_LENGTH)  # type: ignore[union-attr]
+        msg = recv[0]
+        ancdata = recv[1]
+        if ancdata:
+            for level, type_, data in ancdata:
+                if not (level == SOL_SOCKET and type_ == SCM_RIGHTS):
+                    continue
+                self._unix_fds.extend(
+                    ARRAY("i", data[: len(data) - (len(data) % MAX_UNIX_FDS_SIZE)])
+                )
 
         return msg