Improved [Protocol -isEqual:], now more correct and faster

From-SVN: r82619

diff --git a/libobjc/ChangeLog b/libobjc/ChangeLog
index b64433ad1875db69500a86bfd39d39a9a2963ca0..d6ba1f2711437c9e7f1dca1ec7a7bbb140c60082 100644 (file)
--- a/libobjc/ChangeLog
+++ b/libobjc/ChangeLog
@@ -1,3 +1,13 @@
+2004-06-03  Nicola Pero  <n.pero@mi.flashnet.it>
+
+       * Protocol.m ([-isEqual:]): Small optimizations returning
+       immediately if the argument is equal to self, and accessing
+       the argument's name directly if it's a protocol.
+
+2004-06-03  David Ayers  <d.ayers@inode.at>
+
+       * Protocol.m ([-isEqual:]): Test the class of the argument.
+
 2004-05-25  Andrew Pinski  <pinskia@physics.uc.edu>
 
        * configure.ac (includedir): Rename to ...

diff --git a/libobjc/Protocol.m b/libobjc/Protocol.m
index a18d544db404ad6755d96c86915eb7e4b6867072..689d97e73de71d7f0ae505dae627de1c95b727d9 100644 (file)
--- a/libobjc/Protocol.m
+++ b/libobjc/Protocol.m
@@ -150,11 +150,33 @@ struct objc_method_description_list {
   return hash;
 }
 
+/*
+ * Equality between formal protocols is only formal (nothing to do
+ * with actually checking the list of methods they have!).  Two formal
+ * Protocols are equal if and only if they have the same name.
+ *
+ * Please note (for comparisons with other implementations) that
+ * checking the names is equivalent to checking that Protocol A
+ * conforms to Protocol B and Protocol B conforms to Protocol A,
+ * because this happens iff they have the same name.  If they have
+ * different names, A conforms to B if and only if A includes B, but
+ * the situation where A includes B and B includes A is a circular
+ * dependency between Protocols which is forbidden by the compiler, so
+ * A conforms to B and B conforms to A with A and B having different
+ * names is an impossible case.
+ */
 - (BOOL) isEqual: (id)obj
 {
-  if (strcmp (protocol_name, [obj name]) == 0)
+  if (obj == self)
     return YES;
 
+  if ([obj isKindOf: [Protocol class]])
+    {
+      if (strcmp (protocol_name, ((Protocol *)obj)->protocol_name) == 0)
+       return YES;
+    }
+
   return NO;
 }
 @end
+