Re: [Help-smalltalk] [bug] Gtk bug

[Paolo Bonzini]

Gwenael Casaccio wrote:
> On Wednesday 29 April 2009 10:15:48 you wrote:
>> Hi Paolo,
>>
>> It seems that the crashes came when you free a GtkTreeIter or GtkTextIter,
>> you use the free_oop_for_g_object function (in gst-gtk.c) but these are
>> classical structures not GObject.

Almost there: I use gtk_tree_iter_free, but I allocate it with malloc
instead of gtk_tree_iter_copy.

This patch fixes half of it:

diff --git a/packages/gtk/GtkImpl.st b/packages/gtk/GtkImpl.st
index 4b32273..a383fb2 100644
--- a/packages/gtk/GtkImpl.st
+++ b/packages/gtk/GtkImpl.st
@@ -172,9 +172,16 @@ GdkRectangle extend [


 GtkTreeIter class extend [

+    Prototype := nil.
+
+    gcNew [
+       ^self type gcNew
+    ]
+
     new [
        <category: 'instance creation'>
-       ^(self type new)
+        Prototype isNil ifTrue: [ Prototype := self type gcNew ].
+       ^Prototype copy
            addToBeFinalized;
            yourself
     ]
@@ -185,9 +192,16 @@ GtkTreeIter class extend [


 GtkTextIter class extend [

+    Prototype := nil.
+
+    gcNew [
+       ^self type gcNew
+    ]
+
     new [
        <category: 'instance creation'>
-       ^(self type new)
+        Prototype isNil ifTrue: [ Prototype := self type gcNew ].
+       ^Prototype copy
            addToBeFinalized;
            yourself
     ]

Even then, GtkTreeIter>>#free do not set the object to point to NULL,
which may cause double frees.  So we need this too:

diff --git a/packages/gtk/funcs.awk b/packages/gtk/funcs.awk
index 340cfbf..0ca78f6 100644
--- a/packages/gtk/funcs.awk
+++ b/packages/gtk/funcs.awk
@@ -308,3 +308,10 @@ match_function_first_line($0) {
+  if (decl == "free") {
+      print "free"
+      print "    (self isAbsolute and: [ self address > 0 ])"
+      print "\tifTrue: [ self primFree. self address: 0 ]!"
+      decl = "primFree"
+  }
+
   print decl
   print "    <cCall: '" cFuncName "' returning: " retType
   print "\targs: #(" argdecl " )>! !\n"


Still, it's terribly inefficient to use finalization when GC could work
instead.  Many of the helper methods in packages/gtk/GtkImpl.st could
use #gcNew instead of #new.

I'm committing the above patches.  Thanks!

Paolo