}
}
-// This function wasn't written to be reentrant but there is a possiblity of
-// reentrance if something it does causes a shared lib to load and register
-// classes. On Solaris this happens when the wxHashTable is newed, so the first
-// part of the function has been modified to handle it, and a wxASSERT checks
-// against reentrance in the remainder of the function.
+// Reentrance can occur on some platforms (Solaris for one), as the use of hash
+// and string objects can cause other modules to load and register classes
+// before the original call returns. This is handled by keeping the hash table
+// local when it is first created and only assigning it to the global variable
+// when the function is ready to return.
+//
+// That does make the assumption that after the function has completed the
+// first time the problem will no longer happen; all the modules it depends on
+// will have been loaded. The assumption is checked using the 'entry' variable
+// as a reentrance guard, it checks that once the hash table is global it is
+// not accessed multiple times simulateously.
void wxClassInfo::Register()
{
- if ( !sm_classTable )
- {
- wxHashTable *classTable = new wxHashTable(wxKEY_STRING);
-
- // check for reentrance
- if ( sm_classTable )
- delete classTable;
- else
- sm_classTable = classTable;
- }
-
#if wxDEBUG_LEVEL
// reentrance guard - see note above
static int entry = 0;
- wxASSERT_MSG(++entry == 1, _T("wxClassInfo::Register() reentrance"));
#endif // wxDEBUG_LEVEL
+ wxHashTable *classTable;
+
+ if ( !sm_classTable )
+ {
+ // keep the hash local initially, reentrance is possible
+ classTable = new wxHashTable(wxKEY_STRING);
+ }
+ else
+ {
+ // guard againt reentrance once the global has been created
+ wxASSERT_MSG(++entry == 1, _T("wxClassInfo::Register() reentrance"));
+ classTable = sm_classTable;
+ }
+
// Using IMPLEMENT_DYNAMIC_CLASS() macro twice (which may happen if you
// link any object module twice mistakenly, or link twice against wx shared
// library) will break this function because it will enter an infinite loop
// and eventually die with "out of memory" - as this is quite hard to
// detect if you're unaware of this, try to do some checks here.
- wxASSERT_MSG( sm_classTable->Get(m_className) == NULL,
+ wxASSERT_MSG( classTable->Get(m_className) == NULL,
wxString::Format
(
_T("Class \"%s\" already in RTTI table - have you used IMPLEMENT_DYNAMIC_CLASS() multiple times or linked some object file twice)?"),
)
);
- sm_classTable->Put(m_className, (wxObject *)this);
+ classTable->Put(m_className, (wxObject *)this);
+
+ // if we're using a local hash we need to try to make it global
+ if ( sm_classTable != classTable )
+ {
+ if ( !sm_classTable )
+ {
+ // make the hash global
+ sm_classTable = classTable;
+ }
+ else
+ {
+ // the gobal hash has already been created by a reentrant call,
+ // so delete the local hash and try again
+ delete classTable;
+ Register();
+ }
+ }
#if wxDEBUG_LEVEL
- --entry;
+ entry = 0;
#endif // wxDEBUG_LEVEL
}
// wxObjectRefData
// ----------------------------------------------------------------------------
-void wxObjectRefData::DecRef()
+void wxRefCounter::DecRef()
{
+ wxASSERT_MSG( m_count > 0, "invalid ref data count" );
+
if ( --m_count == 0 )
delete this;
}
{
if ( m_refData )
{
- wxASSERT_MSG( m_refData->m_count > 0, _T("invalid ref data count") );
-
m_refData->DecRef();
m_refData = NULL;
}