Initial pass at implementing fully Apple-compatible GC. This requires the code to be built with -fobjc-gc or -fobjc-gc-only, and requires a runtime that implements all of the support functions (GNUstep runtime trunk or 1.5 when it's release).

Currently, there are a few places where we should be calling NSAllocateCollectable() without NSScannedOption, but are actually calling NSZoneMalloc() unless we're in GC mode.  We should not need separate code paths for this anywhere outside NSZone, since NSAllocateCollectable() will work in non-GC mode as well.

A few of the changes should be tweaked slightly so that they do run-time tests.  For example, when compiling with -fobjc-gc, we may be linked against non-GC code, which will use -retain and -release but won't use the memory barriers.  Supporting this nicely is a lot of effort, and I'm not fully convinced it's a good idea.



git-svn-id: svn+ssh://svn.gna.org/svn/gnustep/libs/base/trunk@33104 72102866-910b-0410-8b05-ffd578937521

Source/NSGarbageCollector.m

@@ -27,8 +27,91 @@
 #import	"Foundation/NSGarbageCollector.h"
 
 static NSGarbageCollector	*collector = nil;
-static unsigned			disabled = 0;
 
+#if __OBJC_GC__
+#include <objc/objc-auto.h>
+
+id CFRetain(id obj)
+{
+  return objc_gc_retain(obj);
+}
+
+void CFRelease(id obj)
+{
+  objc_gc_release(obj);
+}
+
+@implementation	NSGarbageCollector
+
++ (id) defaultCollector
+{
+  return collector;
+}
+
++ (void) initialize
+{
+  collector = [self alloc];
+}
+
+- (void) collectIfNeeded
+{
+  objc_collect(OBJC_COLLECT_IF_NEEDED | OBJC_FULL_COLLECTION);
+}
+
+- (void) collectExhaustively
+{
+  objc_collect(OBJC_EXHAUSTIVE_COLLECTION);
+}
+
+- (void) disable
+{
+  objc_gc_disable();
+}
+
+- (void) disableCollectorForPointer: (void *)ptr
+{
+  CFRetain(ptr);
+}
+
+- (void) enable
+{
+  objc_gc_enable();
+}
+
+- (void) enableCollectorForPointer: (void *)ptr
+{
+  CFRelease(ptr);
+}
+
+- (id) init
+{
+  if (self != collector)
+    {
+      [self dealloc];
+      self = nil;
+    }
+  return self;
+}
+
+- (BOOL) isCollecting
+{
+  return NO;
+}
+
+- (BOOL) isEnabled
+{
+	return objc_collectingEnabled();
+}
+
+- (NSZone*) zone
+{
+  return NSDefaultMallocZone();
+}
+@end
+
+#else
+
+static unsigned			disabled = 0;
 #if	GS_WITH_GC
 
 #include <gc/gc.h>
@@ -152,3 +235,4 @@ static NSHashTable	*uncollectable = 0;
 }
 @end
 
+#endif // __OBJC_GC__