sendmsg.c: Added __objc_msg_forward2...

2007-04-09  Andrew Ruder  <andy@aeruder.net>

        * sendmsg.c: Added __objc_msg_forward2, a hook that allows
        external libraries to provide a function that returns the real
        forwarding function based on both the selector and the receiver.
        * objc/objc-api.h: Define __objc_msg_forward2.

From-SVN: r123678

1 files changed, 15 insertions, 10 deletions

diff --git a/libobjc/sendmsg.c b/libobjc/sendmsg.c
index 9453ef3dd46..c1aed1c0f9a 100644
--- a/libobjc/sendmsg.c
+++ b/libobjc/sendmsg.c
@@ -52,10 +52,15 @@ Boston, MA 02110-1301, USA.  */
 /* The uninstalled dispatch table */
 struct sarray *__objc_uninstalled_dtable = 0;   /* !T:MUTEX */
 
-/* Hook for method forwarding. If it is set, is invoked to return a
-   function that performs the real forwarding. Otherwise the libgcc
-   based functions (__builtin_apply and friends) are used. */
+/* Two hooks for method forwarding. If either is set, it is invoked
+ * to return a function that performs the real forwarding.  If both
+ * are set, the result of __objc_msg_forward2 will be preferred over
+ * that of __objc_msg_forward.  If both return NULL or are unset,
+ * the libgcc based functions (__builtin_apply and friends) are
+ * used.
+ */
 IMP (*__objc_msg_forward) (SEL) = NULL;
+IMP (*__objc_msg_forward2) (id, SEL) = NULL;
 
 /* Send +initialize to class */
 static void __objc_send_initialize (Class);
@@ -69,8 +74,7 @@ static void __objc_init_install_dtable (id, SEL);
    return type for the selector.
    __objc_block_forward for structures.
    __objc_double_forward for floats/doubles.
-   __objc_word_forward for pointers or types that fit in registers.
-   */
+   __objc_word_forward for pointers or types that fit in registers. */
 static double __objc_double_forward (id, SEL, ...);
 static id __objc_word_forward (id, SEL, ...);
 typedef struct { id many[8]; } __big;
@@ -87,10 +91,11 @@ id nil_method (id, SEL);
 /* Given a selector, return the proper forwarding implementation. */
 inline
 IMP
-__objc_get_forward_imp (SEL sel)
+__objc_get_forward_imp (id rcv, SEL sel)
 {
   /* If a custom forwarding hook was registered, try getting a forwarding
-   * function from it.  */
+     function from it. There are two forward routine hooks, one that
+     takes the receiver as an argument and one that does not. */
   if (__objc_msg_forward)
     {
       IMP result;
@@ -99,7 +104,7 @@ __objc_get_forward_imp (SEL sel)
     }
 
   /* In all other cases, use the default forwarding functions built using
-   * __builtin_apply and friends.  */
+     __builtin_apply and friends.  */
     {
       const char *t = sel->sel_types;
 
@@ -168,7 +173,7 @@ get_imp (Class class, SEL sel)
 		 is not in the dispatch table.  So the method just
 		 doesn't exist for the class.  Return the forwarding
 		 implementation. */
-	      res = __objc_get_forward_imp (sel);
+             res = __objc_get_forward_imp ((id)class, sel);
 	    }
 	}
     }
@@ -237,7 +242,7 @@ objc_msg_lookup (id receiver, SEL op)
 		{
 		  /* If the method still just doesn't exist for the
 		     class, attempt to forward the method. */
-		  result = __objc_get_forward_imp (op);
+		  result = __objc_get_forward_imp (receiver, op);
 		}
 	    }
 	}