Merge pull request #1201 from RobinD42/fix-issue1198

Fix access to members of transient wx.VisualAttributes

(cherry picked from commit d6324a0578)

CHANGES.rst

@@ -61,7 +61,10 @@ Changes in this release include the following:
 
 * Fix the use of the output parameter in HtmlWindow.OnOpeningURL the same way 
   it was fixed in HtmlWindowInterface.OnHTMLOpeningURL. (#1068)
-  
+
+* Fixed a crashing bug when using a member of a transient wx.VisualAttributes
+  object. Also set the attributes to be read-only to simplify the fix. (#1198).
+
   
 
 

etg/progdlg.py

@@ -46,7 +46,6 @@ def run():
 
 
     c = module.find('wxProgressDialog')
-    tools.fixWindowClass(c)
 
     # Copy methods from the generic to the native class. This is needed
     # because none of the methods are declared in the interface files, and
@@ -59,6 +58,7 @@ def run():
                 not item.isDtor):
             c.addItem(copy.deepcopy(item))
 
+    tools.fixWindowClass(c)
 
     #-----------------------------------------------------------------
     tools.doCommonTweaks(module)

etg/window.py

@@ -35,6 +35,29 @@ def run():
     # Tweak the parsed meta objects in the module object as needed for
     # customizing the generated code and docstrings.
 
+    c = module.find('wxVisualAttributes')
+    assert isinstance(c, etgtools.ClassDef)
+    # Mark the stucture memebers as read-only, and make copies of the values
+    # when fetching them. This is to protect against cases where the
+    # VisualAttributes object is transient and may be GC'd while we still are
+    # using a reference to a C++ member value.
+    c.find('colBg').noSetter = True
+    c.find('colBg').getCode = """\
+        wxColour* clr = new wxColour(sipCpp->colBg);
+        sipPy = wxPyConstructObject((void*)clr, "wxColour", true);
+    """
+    c.find('colFg').noSetter = True
+    c.find('colFg').getCode = """\
+        wxColour* clr = new wxColour(sipCpp->colFg);
+        sipPy = wxPyConstructObject((void*)clr, "wxColour", true);
+    """
+    c.find('font').noSetter = True
+    c.find('font').getCode = """\
+        wxFont* font = new wxFont(sipCpp->font);
+        sipPy = wxPyConstructObject((void*)font, "wxFont", true);
+    """
+
+
     c = module.find('wxWindow')
     assert isinstance(c, etgtools.ClassDef)
     module.addGlobalStr('wxPanelNameStr', c)

etgtools/extractors.py

@@ -206,6 +206,7 @@ class VariableDef(BaseDef):
         self.definition = ''
         self.argsString = ''
         self.pyInt = False
+        self.noSetter = False
         self.__dict__.update(**kw)
         if element is not None:
             self.extract(element)
@@ -247,6 +248,8 @@ class MemberVarDef(VariableDef):
         super(MemberVarDef, self).__init__()
         self.isStatic = False
         self.protection = 'public'
+        self.getCode = ''
+        self.setCode = ''
         self.__dict__.update(kw)
         if element is not None:
             self.extract(element)

etgtools/sip_generator.py

@@ -569,7 +569,19 @@ from .%s import *
         if memberVar.ignored:
             return
         stream.write('%s%s %s' % (indent, memberVar.type, memberVar.name))
-        stream.write('%s;\n\n' % self.annotate(memberVar))
+        stream.write(self.annotate(memberVar))
+        if memberVar.getCode or memberVar.setCode:
+            stream.write('\n%s{\n' % (indent,))
+            if memberVar.getCode:
+                stream.write('%s%%GetCode\n' % (indent))
+                stream.write(nci(memberVar.getCode, len(indent)+4))
+                stream.write('%s%%End\n' % (indent))
+            if memberVar.setCode:
+                stream.write('%s%%SetCode\n' % (indent))
+                stream.write(nci(memberVar.setCode, len(indent)+4))
+                stream.write('%s%%End\n' % (indent))
+            stream.write('%s}' % (indent,))
+        stream.write(';\n\n')
 
 
     def generateProperty(self, prop, stream, indent):
@@ -979,6 +991,8 @@ from .%s import *
         if isinstance(item, extractors.VariableDef):
             if item.pyInt:
                 annotations.append('PyInt')
+            if item.noSetter:
+                annotations.append('NoSetter')
 
         if isinstance(item, extractors.TypedefDef):
             if item.noTypeName:

etgtools/tweaker_tools.py

@@ -261,17 +261,27 @@ def fixWindowClass(klass, hideVirtuals=True, ignoreProtected=True):
         removeVirtuals(klass)
         addWindowVirtuals(klass)
 
-    if not klass.findItem('GetClassDefaultAttributes'):
-        klass.addItem(extractors.WigCode("""\
-            static wxVisualAttributes
-            GetClassDefaultAttributes(wxWindowVariant variant = wxWINDOW_VARIANT_NORMAL);
-            """))
-
     if not ignoreProtected:
         for item in klass.allItems():
             if isinstance(item, extractors.MethodDef) and item.protection == 'protected':
                 item.ignore(False)
 
+    fixDefaultAttributesMethods(klass)
+
+
+def fixDefaultAttributesMethods(klass):
+    if not klass.findItem('GetClassDefaultAttributes'):
+        m = extractors.MethodDef(
+            type='wxVisualAttributes', name='GetClassDefaultAttributes',
+            isStatic=True, protection='public',
+            items=[extractors.ParamDef(
+                type='wxWindowVariant', name='variant', default='wxWINDOW_VARIANT_NORMAL')]
+        )
+        klass.addItem(m)
+
+    if klass.findItem('GetDefaultAttributes'):
+        klass.find('GetDefaultAttributes').mustHaveApp()
+    klass.find('GetClassDefaultAttributes').mustHaveApp()
 
 
 def fixTopLevelWindowClass(klass, hideVirtuals=True, ignoreProtected=True):
@@ -308,6 +318,8 @@ def fixTopLevelWindowClass(klass, hideVirtuals=True, ignoreProtected=True):
             if isinstance(item, extractors.MethodDef) and item.protection == 'protected':
                 item.ignore(False)
 
+    fixDefaultAttributesMethods(klass)
+
 
 
 def fixSizerClass(klass):

unittests/test_window.py

@@ -137,6 +137,31 @@ class WindowTests(wtc.WidgetTestCase):
         wx.DLG_PNT
 
 
+    def test_vizattrs1(self):
+        w = wx.Window(self.frame, -1, (10,10), (50,50))
+        a = w.GetClassDefaultAttributes()
+        assert isinstance(a.colBg, wx.Colour)
+        assert isinstance(a.colFg, wx.Colour)
+        assert isinstance(a.font, wx.Font)
+
+
+    def test_vizattrs2(self):
+        w = wx.Window(self.frame, -1, (10,10), (50,50))
+        assert isinstance(w.GetClassDefaultAttributes().colBg, wx.Colour)
+        assert isinstance(w.GetClassDefaultAttributes().colFg, wx.Colour)
+        assert isinstance(w.GetClassDefaultAttributes().font, wx.Font)
+
+
+    def test_vizattrs3(self):
+        w = wx.Window(self.frame, -1, (10,10), (50,50))
+        a = w.GetClassDefaultAttributes()
+        with self.assertRaises(AttributeError):
+            a.colBg = wx.Colour('blue')
+        with self.assertRaises(AttributeError):
+            a.colFg = wx.Colour('blue')
+        with self.assertRaises(AttributeError):
+            a.font = wx.NORMAL_FONT
+
 #---------------------------------------------------------------------------