use legacy buffer protocol if necessary

jfolz · jfolz · commit d104105e5841 · 2016-05-15T11:58:19.000+02:00
- try new protocol first
- fall back to old protocol if not PY3 and warn about future changes
- raise otherwise
diff --git a/msgpack/_unpacker.pyx b/msgpack/_unpacker.pyx
@@ -15,6 +15,7 @@ from cpython.buffer cimport (
 )
 from cpython.mem cimport PyMem_Malloc, PyMem_Free
 from cpython.object cimport PyCallable_Check
+from cpython.exc cimport PyErr_WarnEx
 
 cdef extern from "Python.h":
     ctypedef struct PyObject
@@ -142,8 +143,14 @@ def unpackb(object packed, object object_hook=None, object list_hook=None,
         if PyObject_GetBuffer(packed, &view, PyBUF_SIMPLE) == 0:
             buf = <char*> view.buf
             buf_len = view.len
+        else:
+            raise
     else:
         PyObject_AsReadBuffer(packed, <const void**>&buf, &buf_len)
+        PyErr_WarnEx(DeprecationWarning,
+                     "unpacking %s requires old buffer protocol,"
+                     "which will be removed in msgpack 1.0" % type(packed),
+                     1)
 
     if encoding is not None:
         if isinstance(encoding, unicode):
diff --git a/msgpack/fallback.py b/msgpack/fallback.py
@@ -3,6 +3,7 @@
 import sys
 import array
 import struct
+import warnings
 
 if sys.version_info[0] == 3:
     PY3 = True
@@ -247,9 +248,17 @@ def __init__(self, file_like=None, read_size=0, use_list=True,
 
     def feed(self, next_bytes):
         assert self._fb_feeding
-        if isinstance(next_bytes, array.array):
-            next_bytes = next_bytes.tostring()
-        view = memoryview(next_bytes)
+        try:
+            view = memoryview(next_bytes)
+        except TypeError:
+            # try to use legacy buffer protocol if 2.7, otherwise re-raise
+            if not PY3:
+                view = memoryview(buffer(next_bytes))
+                warnings.warn("unpacking %s requires old buffer protocol,"
+                              "which will be removed in msgpack 1.0" % type(next_bytes),
+                              DeprecationWarning)
+            else:
+                raise
         assert view.itemsize == 1
         L = len(view)
         if self._fb_buf_n + L - self._fb_sloppiness > self._max_buffer_size:
