New class.

git-svn-id: svn+ssh://svn.gna.org/svn/gnustep/libs/base/trunk@2811 72102866-910b-0410-8b05-ffd578937521
2025-05-20 12:16:40 +00:00 · 1998-06-16 13:52:57 +00:00 · 1998-06-16 13:52:57 +00:00 · 2c5ffb0448
commit 2c5ffb0448
parent f1827b6f35
6 changed files with 212 additions and 5 deletions
--- a/Source/NSProtocolChecker.m
+++ b/Source/NSProtocolChecker.m
@ -0,0 +1,145 @@
+/* Interface for NSMethodSignature for GNUStep
+   Copyright (C) 1995 Free Software Foundation, Inc.
+
+   Written by:  Mike Kienenberger
+   Date: Jun 1998
+   
+   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 Library 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 Library General Public
+   License along with this library; if not, write to the Free
+   Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+   */ 
+
+#import <Foundation/NSProtocolChecker.h>
+#import <Foundation/NSException.h>
+#import <Foundation/NSInvocation.h>
+#import <Foundation/NSMethodSignature.h>
+
+@implementation NSProtocolChecker
+
+// Allocates and initializes an NSProtocolChecker instance that will
+// forward any messages in the aProtocol protocol to anObject, its
+// target. Thus, the checker can be vended in lieu of anObject to
+// restrict the messages that can be sent to anObject. Returns the
+// new instance.
+
+ (id)protocolCheckerWithTarget:(NSObject *)anObject
+			protocol:(Protocol *)aProtocol
+{
+  return [[[NSProtocolChecker alloc] initWithTarget:anObject
+				    protocol:aProtocol] autorelease];
+}
+
+// Forwards any message to the delegate if the method is declared in
+// the checker's protocol; otherwise raises an NSInvalidArgumentException.
+
+- (void)forwardInvocation:(NSInvocation *)anInvocation
+{
+  unsigned int length;
+  void *buffer;
+  
+  if ((struct objc_method_description *)NULL
+      != [self methodDescriptionForSelector:[anInvocation selector]])
+    [[NSException exceptionWithName:NSInvalidArgumentException
+		  reason:@"Method not declared in current protocol"
+		  userInfo:nil]
+      raise];
+      
+  [anInvocation invokeWithTarget:myTarget];
+  
+  length = [[anInvocation methodSignature] methodReturnLength];
+  buffer = (void *)malloc(length);
+  [anInvocation getReturnValue:buffer];
+  
+  if (0 == strcmp([[anInvocation methodSignature] methodReturnType],
+		  [[anInvocation methodSignatureForSelector: 
+				  @selector(init:)] methodReturnType]) )
+    {
+      if (((id)buffer) == myTarget)
+   	{
+	  ((id)buffer) = self;
+	  [anInvocation setReturnValue: buffer];
+   	}
+    }
+  
+  return;
+}
+
+
+- (id)init
+{
+  myProtocol = nil;
+  myTarget = nil;
+  
+  return self;
+}
+
+// Initializes a newly allocated NSProtocolChecker instance that will
+// forward any messages in the aProtocol protocol to anObject, its
+// delegate. Thus, the checker can be vended in lieu of anObject to
+// restrict the messages that can be sent to anObject. If anObject is
+// allowed to be freed or dereferenced by clients, the free method
+// should be included in aProtocol. Returns the new instance.
+
+- (id)initWithTarget:(NSObject *)anObject protocol:(Protocol *)aProtocol
+{
+  [super init];
+  
+  //if (nil != myProtocol)  
+  //  [myProtocol autorelease];
+  myProtocol = aProtocol;
+  //if (nil != myProtocol)  
+  //  [myProtocol retain];
+  
+  if (nil != myTarget)  
+    [myTarget autorelease];
+  myTarget = anObject;
+  if (nil != myTarget)  
+    [myTarget retain];
+  
+  return self;
+}
+
+// Returns an Objective C description for a method in the checker's
+// protocol, or NULL if aSelector isn't declared as an instance method
+// in the protocol.
+
+- (struct objc_method_description *)methodDescriptionForSelector:(SEL)aSelector
+{
+  return [myProtocol descriptionForInstanceMethod:aSelector];
+}
+
+// Returns the protocol object the checker uses to verify whether a
+// given message should be forwarded to its delegate, or the protocol
+// checker should raise an NSInvalidArgumentException.
+
+- (Protocol *)protocol
+{
+  if (nil == myProtocol)
+    [[NSException exceptionWithName:NSInvalidArgumentException
+		  reason:@"No protocol specified"
+		  userInfo:nil]
+      raise];
+  
+  return myProtocol;
+}
+
+// Returns the target of the NSProtocolChecker.
+
+- (NSObject *)target
+{
+  return myTarget;
+}
+
+@end