Merge pull request #557 from RobinD42/fix-issue550

Return None when trying to make a memoryview buffer with a NULL pointer

CHANGES.rst

@@ -22,7 +22,12 @@ Changes in this release include the following:
   tweaks in the AUI_MDI sample in the demo. (#540)
 
 * Added a wx.BUILD_TYPE value to distinguish between development, snapshot,
-  and release builds. The value is also appended to wx.PlatformInfo.
+  and release builds. The value is also appended to wx.PlatformInfo. (Thanks
+  Mesalu!)
+
+* Fix crash when trying to fetch multiple items from a composite data object
+  in wx.DropTarget.OnData. (#550) Also fixed the CustomDragAndDrop sample to
+  not fail on Python 2.7.
 
 
 

demo/CustomDragAndDrop.py

@@ -1,6 +1,6 @@
 #!/usr/bin/env python
 
-from six.moves import cPickle
+import pickle
 import  wx
 
 #----------------------------------------------------------------------
@@ -72,7 +72,7 @@ class DoodlePad(wx.Window):
 
     def StartDragOpperation(self):
         # pickle the lines list
-        linesdata = cPickle.dumps(self.lines, 1)
+        linesdata = pickle.dumps(self.lines)
 
         # create our own data format and use it in a
         # custom data object
@@ -97,10 +97,10 @@ class DoodlePad(wx.Window):
         data.Add(bdata)
 
         # And finally, create the drop source and begin the drag
-        # and drop opperation
+        # and drop operation
         dropSource = wx.DropSource(self)
         dropSource.SetData(data)
-        self.log.WriteText("Begining DragDrop\n")
+        self.log.WriteText("Beginning DragDrop\n")
         result = dropSource.DoDragDrop(wx.Drag_AllowMove)
         self.log.WriteText("DragDrop completed: %d\n" % result)
 
@@ -156,12 +156,14 @@ class DoodleDropTarget(wx.DropTarget):
         if self.GetData():
             # convert it back to a list of lines and give it to the viewer
             linesdata = self.data.GetData()
-            lines = cPickle.loads(linesdata)
-            self.dv.SetLines(lines)
+            if linesdata:
+                lines = pickle.loads(linesdata.tobytes())
+                self.dv.SetLines(lines)
 
         # what is returned signals the source what to do
         # with the original data (move, copy, etc.)  In this
-        # case we just return the suggested value given to us.
+        # case we again just return the suggested value given
+        # to us.
         return d
 
 
@@ -297,7 +299,6 @@ if __name__ == '__main__':
 
     class TestApp(wx.App):
         def OnInit(self):
-            wx.InitAllImageHandlers()
             self.MakeFrame()
             return True
 

src/wxpy_api.sip

@@ -453,12 +453,17 @@ bool i_wxPyCheckForApp(bool raiseException) {
 
 PyObject* i_wxPyMakeBuffer(void* ptr, Py_ssize_t len, bool readOnly=false) {
     // GIL should already be held
-    Py_buffer view;
-    int flags = PyBUF_FORMAT|PyBUF_ND;
-    if (!readOnly)
-        flags |= PyBUF_WRITABLE;
-    PyBuffer_FillInfo(&view, NULL, ptr, len, readOnly ? 1:0, flags);
-    return PyMemoryView_FromBuffer(&view);
+    if (ptr && len) {
+        Py_buffer view;
+        int flags = PyBUF_FORMAT|PyBUF_ND;
+        if (!readOnly)
+            flags |= PyBUF_WRITABLE;
+        PyBuffer_FillInfo(&view, NULL, ptr, len, readOnly ? 1:0, flags);
+        return PyMemoryView_FromBuffer(&view);
+    } else {
+        Py_INCREF(Py_None); return Py_None;
+        // return PyBytes_FromString("");    TODO: None or an empty string?
+    }
 
 //    // TODO: Consider using a sip.array object instead, like this:
 //    // Create a sip.array of bytes, and then convert to a memoryview which is