shithub: choc

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Add reference counts on callback tables so that if a callback destroys
the widget that owns the callback the program doesnt crash.

Subversion-branch: /trunk/chocolate-doom
Subversion-revision: 599

--- a/textscreen/txt_widget.c

+++ b/textscreen/txt_widget.c

@@ -33,6 +33,7 @@

 struct txt_callback_table_s

 {

+    int refcount;

     txt_callback_t *callbacks;

     int num_callbacks;

 };

@@ -44,21 +45,34 @@

     table = malloc(sizeof(txt_callback_table_t));

     table->callbacks = NULL;

     table->num_callbacks = 0;

+    table->refcount = 1;

     return table;

 }

-void TXT_DestroyCallbackTable(txt_callback_table_t *table)

+void TXT_RefCallbackTable(txt_callback_table_t *table)

 {

+    ++table->refcount;

+}

+

+void TXT_UnrefCallbackTable(txt_callback_table_t *table)

+{

     int i;

-    for (i=0; i<table->num_callbacks; ++i)

+    --table->refcount;

+

+    if (table->refcount == 0)

     {

-        free(table->callbacks[i].signal_name);

-    }

+        // No more references to this table

+

+        for (i=0; i<table->num_callbacks; ++i)

+        {

+            free(table->callbacks[i].signal_name);

+        }

-    free(table->callbacks);

-    free(table);

+        free(table->callbacks);

+        free(table);

+    }

 }

 void TXT_InitWidget(TXT_UNCAST_ARG(widget), txt_widget_class_t *widget_class)

@@ -111,6 +125,11 @@

     table = widget->callback_table;

+    // Don't destroy the table while we're searching through it

+    // (one of the callbacks may destroy this window)

+

+    TXT_RefCallbackTable(table);

+

     // Search the table for all callbacks with this name and invoke

     // the functions.

@@ -121,6 +140,10 @@

             table->callbacks[i].func(widget, table->callbacks[i].user_data);

         }

     }

+

+    // Finished using the table

+

+    TXT_UnrefCallbackTable(table);

 }

 void TXT_CalcWidgetSize(TXT_UNCAST_ARG(widget))

@@ -148,7 +171,7 @@

     TXT_CAST_ARG(txt_widget_t, widget);

     widget->widget_class->destructor(widget);

-    TXT_DestroyCallbackTable(widget->callback_table);

+    TXT_UnrefCallbackTable(widget->callback_table);

     free(widget);

 }