Fix JS_[GS]etContextThread return type; add JSCLASS_NEW_RESOLVE_GETS_START (196966, r=shaver).

js/src/jsapi.c

@@ -3982,13 +3982,13 @@ JS_ErrorFromException(JSContext *cx, jsval v)
 }
 
 #ifdef JS_THREADSAFE
-JS_PUBLIC_API(intN)
+JS_PUBLIC_API(jsword)
 JS_GetContextThread(JSContext *cx)
 {
     return cx->thread;
 }
 
-JS_PUBLIC_API(intN)
+JS_PUBLIC_API(jsword)
 JS_SetContextThread(JSContext *cx)
 {
     intN old = cx->thread;

js/src/jsapi.h

@@ -721,6 +721,10 @@ struct JSClass {
 #define JSCLASS_NEW_RESOLVE             (1<<2)  /* has JSNewResolveOp hook */
 #define JSCLASS_PRIVATE_IS_NSISUPPORTS  (1<<3)  /* private is (nsISupports *) */
 #define JSCLASS_SHARE_ALL_PROPERTIES    (1<<4)  /* all properties are SHARED */
+#define JSCLASS_NEW_RESOLVE_GETS_START  (1<<5)  /* JSNewResolveOp gets starting
+                                                   object in prototype chain
+                                                   passed in via *objp in/out
+                                                   parameter */
 
 /*
  * To reserve slots fetched and stored via JS_Get/SetReservedSlot, bitwise-or
@@ -1692,11 +1696,10 @@ JS_ErrorFromException(JSContext *cx, jsval v);
  * indicates that ClearContextThread has been called on this context
  * since the last SetContextThread, or non-0, which indicates the opposite.
  */
-
-extern JS_PUBLIC_API(intN)
+extern JS_PUBLIC_API(jsword)
 JS_GetContextThread(JSContext *cx);
 
-extern JS_PUBLIC_API(intN)
+extern JS_PUBLIC_API(jsword)
 JS_SetContextThread(JSContext *cx);
 
 extern JS_PUBLIC_API(intN)

js/src/jsobj.c

@@ -2178,6 +2178,7 @@ js_LookupProperty(JSContext *cx, JSObject *obj, jsid id, JSObject **objp,
                   JSProperty **propp)
 #endif
 {
+    JSObject *start, *obj2, *proto;
     JSScope *scope;
     JSScopeProperty *sprop;
     JSClass *clasp;
@@ -2189,7 +2190,6 @@ js_LookupProperty(JSContext *cx, JSObject *obj, jsid id, JSObject **objp,
     JSNewResolveOp newresolve;
     uintN flags;
     uint32 format;
-    JSObject *obj2, *proto;
     JSBool ok;
 
     /*
@@ -2199,6 +2199,7 @@ js_LookupProperty(JSContext *cx, JSObject *obj, jsid id, JSObject **objp,
     CHECK_FOR_FUNNY_INDEX(id);
 
     /* Search scopes starting with obj and following the prototype link. */
+    start = obj;
     for (;;) {
         JS_LOCK_OBJ(cx, obj);
         SET_OBJ_INFO(obj, file, line);
@@ -2269,7 +2270,9 @@ js_LookupProperty(JSContext *cx, JSObject *obj, jsid id, JSObject **objp,
                             flags |= JSRESOLVE_ASSIGNING;
                         }
                     }
-                    obj2 = NULL;
+                    obj2 = (clasp->flags & JSCLASS_NEW_RESOLVE_GETS_START)
+                           ? start
+                           : NULL;
                     JS_UNLOCK_OBJ(cx, obj);
                     ok = newresolve(cx, obj, ID_TO_VALUE(id), flags, &obj2);
                     if (!ok)

js/src/jspubtd.h

@@ -196,6 +196,22 @@ typedef JSBool
  * The *objp out parameter, on success, should be null to indicate that id
  * was not resolved; and non-null, referring to obj or one of its prototypes,
  * if id was resolved.
+ *
+ * This hook instead of JSResolveOp is called via the JSClass.resolve member
+ * if JSCLASS_NEW_RESOLVE is set in JSClass.flags.
+ *
+ * Setting JSCLASS_NEW_RESOLVE and JSCLASS_NEW_RESOLVE_GETS_START further
+ * extends this hook by passing in the starting object on the prototype chain
+ * via *objp.  Thus a resolve hook implementation may define the property id
+ * being resolved in the object in which the id was first sought, rather than
+ * in a prototype object whose class led to the resolve hook being called.
+ *
+ * When using JSCLASS_NEW_RESOLVE_GETS_START, the resolve hook must therefore
+ * null *objp to signify "not resolved".  With only JSCLASS_NEW_RESOLVE and no
+ * JSCLASS_NEW_RESOLVE_GETS_START, the hook can assume *objp is null on entry.
+ * This is not good practice, but enough existing hook implementations count
+ * on it that we can't break compatibility by passing the starting object in
+ * *objp without a new JSClass flag.
  */
 typedef JSBool
 (* JS_DLL_CALLBACK JSNewResolveOp)(JSContext *cx, JSObject *obj, jsval id,