Fix problems with memoryview object. There is still more to do to finish PEP 3118. The memory-view object needs to be fleshed out and the struct module needs to be modified.

Include/memoryobject.h

@@ -21,7 +21,8 @@ PyAPI_DATA(PyTypeObject) PyMemoryView_Type;
 
 #define Py_END_OF_MEMORY	(-1)
 
-PyAPI_FUNC(PyObject *) PyMemoryView_GetContiguous(PyObject *base, int buffertype, 
+PyAPI_FUNC(PyObject *) PyMemoryView_GetContiguous(PyObject *base, 
+						  int buffertype, 
 						  char fort);
 
 	/* Return a contiguous chunk of memory representing the buffer
@@ -32,17 +33,17 @@ PyAPI_FUNC(PyObject *) PyMemoryView_GetContiguous(PyObject *base, int buffertype
 	   data-copying will be done. 
 
 	   The buffertype argument can be PyBUF_READ, PyBUF_WRITE,
-           PyBUF_UPDATEIFCOPY to determine whether the returned buffer
+	   PyBUF_SHADOW to determine whether the returned buffer
 	   should be READONLY, WRITABLE, or set to update the
 	   original buffer if a copy must be made.  If buffertype is
 	   PyBUF_WRITE and the buffer is not contiguous an error will
 	   be raised.  In this circumstance, the user can use
-           PyBUF_UPDATEIFCOPY to ensure that a a writable temporary
+	   PyBUF_SHADOW to ensure that a a writable temporary
 	   contiguous buffer is returned.  The contents of this
 	   contiguous buffer will be copied back into the original
 	   object after the memoryview object is deleted as long as
-           the original object is writable and allows setting its
-           memory to "readonly".  If this is not allowed by the
+	   the original object is writable and allows setting an
+	   exclusive write lock. If this is not allowed by the
 	   original object, then a BufferError is raised.
 	   
 	   If the object is multi-dimensional and if fortran is 'F',

Include/object.h

@@ -164,7 +164,7 @@ typedef void (*releasebufferproc)(PyObject *, Py_buffer *);
 #define PyBUF_WRITABLE 0x0002
 /*  we used to include an E, backwards compatible alias  */
 #define PyBUF_WRITEABLE PyBUF_WRITABLE
-#define PyBUF_LOCKDATA 0x0004
+#define PyBUF_LOCK 0x0004
 #define PyBUF_FORMAT 0x0008
 #define PyBUF_ND 0x0010
 #define PyBUF_STRIDES (0x0020 | PyBUF_ND)
@@ -175,19 +175,25 @@ typedef void (*releasebufferproc)(PyObject *, Py_buffer *);
 
 #define PyBUF_CONTIG (PyBUF_ND | PyBUF_WRITABLE)
 #define PyBUF_CONTIG_RO (PyBUF_ND)
-#define PyBUF_CONTIG_LCK (PyBUF_ND | PyBUF_LOCKDATA)
+#define PyBUF_CONTIG_LCK (PyBUF_ND | PyBUF_LOCK)
+#define PyBUF_CONTIG_XLCK (PyBUF_ND | PyBUF_LOCK | PyBUF_WRITABLE)
 
 #define PyBUF_STRIDED (PyBUF_STRIDES | PyBUF_WRITABLE)
 #define PyBUF_STRIDED_RO (PyBUF_STRIDES)
-#define PyBUF_STRIDED_LCK (PyBUF_STRIDES | PyBUF_LOCKDATA)
+#define PyBUF_STRIDED_LCK (PyBUF_STRIDES | PyBUF_LOCK)
+#define PyBUF_STRIDED_XLCK (PyBUF_STRIDES | PyBUF_LOCK | PyBUF_WRITABLE)
 
 #define PyBUF_RECORDS (PyBUF_STRIDES | PyBUF_WRITABLE | PyBUF_FORMAT)
 #define PyBUF_RECORDS_RO (PyBUF_STRIDES | PyBUF_FORMAT)
-#define PyBUF_RECORDS_LCK (PyBUF_STRIDES | PyBUF_LOCKDATA | PyBUF_FORMAT)
+#define PyBUF_RECORDS_LCK (PyBUF_STRIDES | PyBUF_LOCK | PyBUF_FORMAT)
+#define PyBUF_RECORDS_XLCK (PyBUF_STRIDES | PyBUF_LOCK | PyBUF_WRITABLE \
+			    | PyBUF_FORMAT)
 
 #define PyBUF_FULL (PyBUF_INDIRECT | PyBUF_WRITABLE | PyBUF_FORMAT)
 #define PyBUF_FULL_RO (PyBUF_INDIRECT | PyBUF_FORMAT)
-#define PyBUF_FULL_LCK (PyBUF_INDIRECT | PyBUF_LOCKDATA | PyBUF_FORMAT)
+#define PyBUF_FULL_LCK (PyBUF_INDIRECT | PyBUF_LOCK | PyBUF_FORMAT)
+#define PyBUF_FULL_XLCK (PyBUF_INDIRECT | PyBUF_LOCK | PyBUF_WRITABLE \
+			 | PyBUF_FORMAT)
 
 
 #define PyBUF_READ  0x100

Objects/abstract.c

@@ -653,14 +653,14 @@ PyBuffer_FillInfo(Py_buffer *view, void *buf, Py_ssize_t len,
 	      int readonly, int flags)
 {	 
 	if (view == NULL) return 0;
-        if (((flags & PyBUF_LOCKDATA) == PyBUF_LOCKDATA) && 
-            readonly != -1) {
+	if (((flags & PyBUF_LOCK) == PyBUF_LOCK) && 
+	    readonly >= 0) {
 		PyErr_SetString(PyExc_BufferError, 
-                                "Cannot make this object read-only.");
+				"Cannot lock this object.");
 		return -1;
 	}
 	if (((flags & PyBUF_WRITABLE) == PyBUF_WRITABLE) &&
-            readonly == 1) {
+	    (readonly == 1)) {
 		PyErr_SetString(PyExc_BufferError,
 				"Object is not writable.");
 		return -1;

Objects/memoryobject.c

@@ -196,7 +196,9 @@ _indirect_copy_nd(char *dest, Py_buffer *view, char fort)
                 a contiguous buffer if it is not. The view will point to
                 the shadow buffer which can be written to and then
                 will be copied back into the other buffer when the memory
-                view is de-allocated.
+                view is de-allocated.  While the shadow buffer is 
+		being used, it will have an exclusive write lock on 
+		the original buffer. 
  */
 
 PyObject *
@@ -224,7 +226,7 @@ PyMemoryView_GetContiguous(PyObject *obj, int buffertype, char fort)
                 flags = PyBUF_FULL;
                 break;
         case PyBUF_SHADOW:
-                flags = PyBUF_FULL_LCK;
+                flags = PyBUF_FULL_XLCK;
                 break;
         }
 
@@ -431,10 +433,6 @@ memory_dealloc(PyMemoryViewObject *self)
 static PyObject *
 memory_repr(PyMemoryViewObject *self)
 {
-	/* XXX(nnorwitz): the code should be different or remove condition. */
-	if (self->base == NULL)
-		return PyUnicode_FromFormat("<memory at %p>", self);
-	else
 	return PyUnicode_FromFormat("<memory at %p>", self);
 }
 
@@ -502,6 +500,14 @@ memory_subscript(PyMemoryViewObject *self, PyObject *key)
 			/* Return a bytes object */
 			char *ptr;
 			ptr = (char *)view->buf;
+			if (result < 0) {
+				result += view->shape[0];
+			}
+			if ((result < 0) || (result > view->shape[0])) {
+				PyErr_SetString(PyExc_IndexError,
+						"index out of bounds");
+				return NULL;
+			}
 			if (view->strides == NULL)
 				ptr += view->itemsize * result;
 			else
@@ -517,14 +523,20 @@ memory_subscript(PyMemoryViewObject *self, PyObject *key)
 			/* Return a new memory-view object */
 			Py_buffer newview;
 			memset(&newview, 0, sizeof(newview));
+			/* XXX:  This needs to be fixed so it 
+			         actually returns a sub-view
+			*/
 			return PyMemoryView_FromMemory(&newview);
 		}
 	}
 
+	/* Need to support getting a sliced view */
         Py_INCREF(Py_NotImplemented);
         return Py_NotImplemented;
 }
 
+
+/* Need to support assigning memory if we can */
 static int
 memory_ass_sub(PyMemoryViewObject *self, PyObject *key, PyObject *value)
 {