New macros for CLANG compatibility

git-svn-id: svn+ssh://svn.gna.org/svn/gnustep/libs/base/trunk@28402 72102866-910b-0410-8b05-ffd578937521

ChangeLog

@@ -1,3 +1,8 @@
+2009-07-21 Richard Frith-Macdonald <rfm@gnu.org>
+
+	* Source/GSInternal.h: New macros for CLANG/non-fragile ivar compat.
+	* Source/NSOperation.m: Use new macros.
+
 2009-07-17 Richard Frith-Macdonald <rfm@gnu.org>
 
 	* Source/NSOperation.m: Fix includes and text of comments at start

Source/GSInternal.h

@@ -0,0 +1,121 @@
+/* GSInternal
+   Copyright (C) 2009 Free Software Foundation, Inc.
+
+   Written by:  Richard Frith-Macdonald <rfm@gnu.org>
+   
+   This file is part of the GNUstep Base Library.
+
+   This library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2 of the License, or (at your option) any later version.
+   
+   This library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Library General Public License for more details.
+   
+   You should have received a copy of the GNU Lesser General Public
+   License along with this library; if not, write to the Free
+   Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
+   MA 02111 USA.
+*/ 
+
+
+/* This file defines macros for managing internal (hidden) instance variables
+ * of a public class so that users of the public class don't need to recompile
+ * their code when the class implementation is changed in new versions of the
+ * library.
+ *
+ * The public class MUST contain an instance variable 'id _internal;' to be
+ * used as a pointer to a private class containing the ivars.
+ *
+ * Before including this file, you must define 'GSInternal' to be the name
+ * of your public class with * 'Internal' appended.
+ * eg. if your class is called 'MyClass' then use the following define:
+ * #define GSInternal MyClassInternal
+ *
+ * After including this file you can use the GS_BEGIN_INTERNAL() and
+ * GS_END_INTERNAL() macros to bracket the declaration of the instance
+ * variables.
+ *
+ * You use GS_CREATE_INTERNAL() in your intialiser to create the object
+ * holding the internal instance variables, and GS_DESTROY_INTERNAL() to
+ * get rid of that object (only do this if '_internal' is not nil) in
+ * your -dealloc method.
+ *
+ * Instance variables are referenced using the 'internal->ivar' suntax or
+ * the GSIV(classname,object,ivar) macro.
+ *
+ * If built with CLANG (assumed to support non-fragile instance variables)
+ * rather than GCC, the compiler/runtime can simply declare instance variables
+ * within the implementation file so that they are not part of the public ABI,
+ * in which case the macros here mostly reduce to nothing and the generated
+ * code can be much more efficient.
+ */
+#if	defined(__GNUC__)
+
+/* Code for GCC.
+ */
+
+/* Start declaration of internal ivars.
+ */
+#define	GS_BEGIN_INTERNAL(name) \
+@interface	name ## Internal : NSObject \
+{ \
+  @public
+
+/* Finish declaration of internal ivars.
+ */
+#define	GS_END_INTERNAL(name) \
+} \
+@end \
+@implementation	name ## Internal \
+@end
+
+/* Create holder for internal ivars.
+ */
+#define	GS_CREATE_INTERNAL(name) \
+_internal = [name ## Internal new];
+
+/* Create holder for internal ivars.
+ */
+#define	GS_DESTROY_INTERNAL(name) \
+DESTROY(_internal);
+
+#undef	internal
+#define	internal	((GSInternal*)_internal)
+#undef	GSIVr
+#define	GSIVar(X,Y)	(((X ## Internal*)_internal)->Y)
+
+#else	/* defined(__GNUC__) */
+
+/* Not GCC, so we assume this is CLANG with support for non-fragile ivars
+ */
+
+#define	GS_BEGIN_INTERNAL(name) \
+@interface	name \
+{
+
+/* Finish declaration of internal ivars.
+ */
+#define	GS_END_INTERNAL(name) \
+} \
+@end
+
+/* Create holder for internal ivars (nothing to do).
+ */
+#define	GS_CREATE_INTERNAL(name)
+
+#define	GS_DESTROY_INTERNAL(name)
+
+/* Define constant to reference internal ivars.
+ */
+#undef	internal
+#define	internal	self
+#undef	GSIVar
+#define	GSIVar(X,Y)	(self->Y)
+
+#endif	/* defined(__GNUC__) */
+
+

Source/NSOperation.m

@@ -31,9 +31,9 @@
 #import "Foundation/NSEnumerator.h"
 #import "Foundation/NSException.h"
 
-@interface	NSOperationInternal : NSObject
-{
-@public
+#define	GSInternal	NSOperationInternal
+#include	"GSInternal.h"
+GS_BEGIN_INTERNAL(NSOperation)
   NSOperationQueuePriority priority;
   BOOL cancelled;
   BOOL concurrent;
@@ -41,27 +41,17 @@
   BOOL finished;
   BOOL ready;
   NSMutableArray *dependencies;
-}
-@end
-
-@implementation	NSOperationInternal
-/* As long as this class does nothing but act as a container for ivars,
- * we can easily remove it at a later date using a global substitution
- * to replace all the code of the form 'internal->ivar' with 'ivar'.
- */
-@end
+GS_END_INTERNAL(NSOperation)
 
 
 @implementation NSOperation : NSObject
 
-#define	internal	((NSOperationInternal*)_internal)
-
 - (void) dealloc
 {
-  if (_internal != nil)
+  if (internal != nil)
     {
       RELEASE(internal->dependencies);
-      [_internal release];
+      GS_DESTROY_INTERNAL(NSOperation);
     }
   [super dealloc];
 }
@@ -70,7 +60,7 @@
 {
   if ((self = [super init]) != nil)
     {
-      _internal = [NSOperationInternal new];
+      GS_CREATE_INTERNAL(NSOperation);
       internal->priority = NSOperationQueuePriorityNormal;
       internal->dependencies = [[NSMutableArray alloc] initWithCapacity: 5];
     }
@@ -172,33 +162,24 @@
 @end
 
 
-@interface NSOperationQueueInternal : NSObject
-{
-  @public
+#undef	GSInternal
+#define	GSInternal	NSOperationQueueInternal
+#include	"GSInternal.h"
+GS_BEGIN_INTERNAL(NSOperationQueue)
   NSMutableArray	*operations;
   BOOL			suspended;
   NSInteger		count;
-}
-@end
+GS_END_INTERNAL(NSOperationQueue)
 
-@implementation NSOperationQueueInternal : NSObject
-/* As long as this class does nothing but act as a container for ivars,
- * we can easily remove it at a later date using a global substitution
- * to replace all the code of the form 'internal->ivar' with 'ivar'.
- */
-@end
 
 @implementation NSOperationQueue
 
-#undef	internal
-#define	internal	((NSOperationQueueInternal*)_internal)
-
 - (void) dealloc
 {
   if (_internal != nil)
     {
       [internal->operations release];
-      [_internal release];
+      GS_DESTROY_INTERNAL(NSOperationQueue);
     }
   [super dealloc];
 }
@@ -207,7 +188,7 @@
 {
   if ((self = [super init]) != nil)
     {
-      _internal = [NSOperationQueueInternal new];
+      GS_CREATE_INTERNAL(NSOperationQueue);
       internal->suspended = NO;
       internal->count = NSOperationQueueDefaultMaxConcurrentOperationCount;
       internal->operations = [NSMutableArray new];