Merge pull request #62 from benoit-pierre/fix_python3_buffer_abstraction

vasily-v-ryabov · web-flow · commit 3ab64bf65e01 · 2016-10-25T20:53:21.000+03:00
protocol/display: fix Python 3 buffer abstraction
diff --git a/Xlib/protocol/display.py b/Xlib/protocol/display.py
@@ -42,12 +42,36 @@
 from . import event
 
 if PY3:
-    def buffer(object, offset=None, size=None):
-        if offset is None:
-            offset = 0
+
+    class bytesview(object):
+
+        def __init__(self, data, offset=0, size=None):
+            if size is None:
+                size = len(data)-offset
+            if isinstance(data, bytes):
+                view = memoryview(data)
+            elif isinstance(data, bytesview):
+                view = data.view
+            else:
+                raise TypeError('unsupported type: {}'.format(type(data)))
+            self.view = view[offset:offset+size]
+
+        def __len__(self):
+            return len(self.view)
+
+        def __getitem__(self, key):
+            if isinstance(key, slice):
+                return bytes(self.view[key])
+            return self.view[key]
+
+else:
+
+    def bytesview(data, offset=0, size=None):
+        if not isinstance(data, (bytes, buffer)):
+            raise TypeError('unsupported type: {}'.format(type(data)))
         if size is None:
-            size = len(object)-offset
-        return memoryview(object)[offset:offset+size]
+            size = len(data)-offset
+        return buffer(data, offset, size)
 
 
 class Display(object):
@@ -706,7 +730,7 @@ def parse_error_response(self, request):
         estruct = self.error_classes.get(code, error.XError)
 
         e = estruct(self, self.data_recv[:32])
-        self.data_recv = buffer(self.data_recv, 32)
+        self.data_recv = bytesview(self.data_recv, 32)
 
         # print 'recv Error:', e
 
@@ -760,7 +784,7 @@ def parse_request_response(self, request):
         req._parse_response(self.data_recv[:self.recv_packet_len])
         # print 'recv Request:', req
 
-        self.data_recv = buffer(self.data_recv, self.recv_packet_len)
+        self.data_recv = bytesview(self.data_recv, self.recv_packet_len)
         self.recv_packet_len = 0
 
 
@@ -797,7 +821,7 @@ def parse_event_response(self, etype):
         if etype == ge.GenericEventCode:
             self.recv_packet_len = 0
 
-        self.data_recv = buffer(self.data_recv, length)
+        self.data_recv = bytesview(self.data_recv, length)
 
         # Drop all requests having an error handler,
         # but which obviously succeded.
diff --git a/test/test_bytesview.py b/test/test_bytesview.py
@@ -0,0 +1,27 @@
+
+import unittest
+
+# Python 2/3 compatibility.
+from six import indexbytes, text_type
+
+from Xlib.protocol.display import bytesview
+
+
+class BytesViewTest(unittest.TestCase):
+
+    def test(self):
+        with self.assertRaises(TypeError):
+            bytesview(text_type('foobar'))
+        data = b'0123456789ABCDEF'
+        view = bytesview(data)
+        self.assertEqual(len(view), 16)
+        self.assertEqual(view[:], data)
+        self.assertIsInstance(view[:], bytes)
+        self.assertEqual(view[5:-6], b'56789')
+        self.assertEqual(indexbytes(view, 7), ord('7'))
+        view = bytesview(view, 5)
+        self.assertEqual(view[:], b'56789ABCDEF')
+        self.assertEqual(indexbytes(view, 4), ord('9'))
+        view = bytesview(view, 0, 5)
+        self.assertEqual(view[:], b'56789')
+        self.assertEqual(indexbytes(view, 1), ord('6'))
