Objective-C layer: Track Lisp backing status by class instead of by instance.

darcs-hash:0094d958feb2fd5e1715f953f6a67249850f095c

2 files changed, 21 insertions, 13 deletions

diff --git a/Objective-C/NSObject-ObjectiveCLWrapperLink.h b/Objective-C/NSObject-ObjectiveCLWrapperLink.h
index 691c6fc..4c4cc4c 100644
--- a/Objective-C/NSObject-ObjectiveCLWrapperLink.h
+++ b/Objective-C/NSObject-ObjectiveCLWrapperLink.h
@@ -9,6 +9,6 @@ void
 objcl_shutdown_instance_wrappers (void);
 
 @interface NSObject (ObjectiveCLWrapperLink)
--(BOOL) __objcl_isBackedByLispInstance;
--(void) __objcl_setBackedByLispInstance: (BOOL)backed_p;
++(BOOL) __objcl_isBackedByLispClass;
++(void) __objcl_setBackedByLispClass: (BOOL)backed_p;
 @end /* NSObject (ObjectiveCL) */
diff --git a/Objective-C/NSObject-ObjectiveCLWrapperLink.m b/Objective-C/NSObject-ObjectiveCLWrapperLink.m
index 665d302..8d34a19 100644
--- a/Objective-C/NSObject-ObjectiveCLWrapperLink.m
+++ b/Objective-C/NSObject-ObjectiveCLWrapperLink.m
@@ -5,36 +5,44 @@
 #import <Foundation/NSObject.h>
 #import <Foundation/NSString.h>
 
-static NSMutableSet *lisp_backed_objects = nil;
+/* A class is considered Lisp-backed if some of its methods are
+   implemented as Lisp callbacks.  This is true if and only if
+   @selector(retain) and @selector(release) are overridden by
+   Objective-CL.  In this case, the corresponding Lisp objects are
+   stored in a regular hash table instead of a weak one, as they may
+   hold data (like CLOS slots) that we can't do without as long as the
+   Objective-C instance is referenced from anywhere (where `anywhere'
+   includes both the Lisp and Objective-C worlds). */
+static NSMutableSet *lisp_backed_classes = nil;
 
 void
 objcl_initialise_instance_wrappers (void)
 {
-  if (lisp_backed_objects == nil)
-    lisp_backed_objects = [[NSMutableSet alloc] init];
+  if (lisp_backed_classes == nil)
+    lisp_backed_classes = [[NSMutableSet alloc] init];
 }
 
 void
 objcl_shutdown_instance_wrappers (void)
 {
-  if (lisp_backed_objects != nil)
+  if (lisp_backed_classes != nil)
     {
-      [lisp_backed_objects release];
-      lisp_backed_objects = nil;
+      [lisp_backed_classes release];
+      lisp_backed_classes = nil;
     }
 }
 
 @implementation NSObject (ObjectiveCLWrapperLink)
--(BOOL) __objcl_isBackedByLispInstance
++(BOOL) __objcl_isBackedByLispClass
 {
-  return [lisp_backed_objects containsObject: self];
+  return [lisp_backed_classes containsObject: self];
 }
 
--(void) __objcl_setBackedByLispInstance: (BOOL)backed_p
++(void) __objcl_setBackedByLispClass: (BOOL)backed_p
 {
   if (backed_p)
-    [lisp_backed_objects addObject: self];
+    [lisp_backed_classes addObject: self];
   else
-    [lisp_backed_objects removeObject: self];
+    [lisp_backed_classes removeObject: self];
 }
 @end /* NSObject (ObjectiveCL) */