Checking in shaver's patch for bug 78100, adding JS_GetExternalStringGCType (sr=brendan&jband).

js/src/jsapi.c

@@ -1690,6 +1690,17 @@ JS_NewExternalString(JSContext *cx, jschar *chars, size_t length, intN type)
     return str;
 }
 
+JS_PUBLIC_API(intN)
+JS_GetExternalStringGCType(JSRuntime *rt, JSString *str)
+{
+    uint8 type = *js_GetGCThingFlags(str) & GCF_TYPEMASK;
+
+    JS_ASSERT(type == GCX_STRING || type >= GCX_EXTERNAL_STRING);
+    if (type == GCX_STRING)
+        return -1;
+    return (intN)type;
+}
+
 /************************************************************************/
 
 JS_PUBLIC_API(void)

js/src/jsapi.h

@@ -640,6 +640,13 @@ JS_RemoveExternalStringFinalizer(JSStringFinalizeOp finalizer);
 extern JS_PUBLIC_API(JSString *)
 JS_NewExternalString(JSContext *cx, jschar *chars, size_t length, intN type);
 
+/*
+ * Returns the external-string finalizer index for this string, or -1 if it is
+ * an "internal" (native to JS engine) string.
+ */
+extern JS_PUBLIC_API(intN)
+JS_GetExternalStringGCType(JSRuntime *rt, JSString *str);
+
 /************************************************************************/
 
 /*

js/src/jsgc.c

@@ -201,8 +201,8 @@ gc_new_arena(JSArenaPool *pool)
     return thing;
 }
 
-static uint8 *
-gc_find_flags(void *thing)
+uint8 *
+js_GetGCThingFlags(void *thing)
 {
     JSGCPageInfo *pi;
     uint8 *flagp;
@@ -214,9 +214,11 @@ gc_find_flags(void *thing)
     return flagp;
 }
 
-JSBool js_IsAboutToBeFinalized(JSContext *cx, void *thing)
+JSBool
+js_IsAboutToBeFinalized(JSContext *cx, void *thing)
 {
-    uint8 flags = *gc_find_flags(thing);
+    uint8 flags = *js_GetGCThingFlags(thing);
+
     return !(flags & (GCF_MARK | GCF_LOCKMASK | GCF_FINAL));
 }
 
@@ -518,7 +520,7 @@ retry:
         }
 
         /* Find the flags pointer given thing's address. */
-        flagp = gc_find_flags(thing);
+        flagp = js_GetGCThingFlags(thing);
     }
     *flagp = (uint8)flags;
     rt->gcBytes += sizeof(JSGCThing) + sizeof(uint8);
@@ -544,7 +546,7 @@ js_LockGCThing(JSContext *cx, void *thing)
 
     if (!thing)
 	return JS_TRUE;
-    flagp = gc_find_flags(thing);
+    flagp = js_GetGCThingFlags(thing);
     flags = *flagp;
 
     ok = JS_TRUE;
@@ -616,7 +618,7 @@ js_UnlockGCThing(JSContext *cx, void *thing)
 
     if (!thing)
 	return JS_TRUE;
-    flagp = gc_find_flags(thing);
+    flagp = js_GetGCThingFlags(thing);
     flags = *flagp;
 
     rt = cx->runtime;
@@ -668,7 +670,7 @@ JS_EXPORT_DATA(void *) js_LiveThingToFind;
 static const char *
 gc_object_class_name(void* thing)
 {
-    uint8 *flagp = gc_find_flags(thing);
+    uint8 *flagp = js_GetGCThingFlags(thing);
     const char *className = "";
 
     if (flagp && ((*flagp & GCF_TYPEMASK) == GCX_OBJECT)) {
@@ -788,7 +790,7 @@ js_MarkGCThing(JSContext *cx, void *thing, void *arg)
     if (!thing)
 	return;
 
-    flagp = gc_find_flags(thing);
+    flagp = js_GetGCThingFlags(thing);
     flags = *flagp;
     JS_ASSERT(flags != GCF_FINAL);
 #ifdef GC_MARK_DEBUG

js/src/jsgc.h

@@ -59,6 +59,9 @@ JS_BEGIN_EXTERN_C
 #define GCF_LOCKMASK    (JS_BITMASK(8 - GCF_LOCKSHIFT) << GCF_LOCKSHIFT)
 #define GCF_LOCK        JS_BIT(GCF_LOCKSHIFT)   /* lock request bit in API */
 
+extern uint8 *
+js_GetGCThingFlags(void *thing);
+
 /* These are compatible with JSDHashEntryStub. */
 struct JSGCRootHashEntry {
     JSDHashEntryHdr hdr;

js/src/jspubtd.h

@@ -275,11 +275,16 @@ typedef JSBool
                                     JSBool *bp);
 
 /*
- * Function type for JSClass.mark and JSObjectOps.mark, called from the GC
- * to scan live GC-things reachable from obj's private data.  For each such
- * private thing, an implementation must call js_MarkGCThing(cx, thing, arg).
- * The trailing arg is used for GC_MARK_DEBUG-mode heap dumping and ref-path
- * tracing.
+ * Function type for JSClass.mark and JSObjectOps.mark, called from the GC to
+ * scan live GC-things reachable from obj's private data structure.  For each
+ * such thing, a mark implementation must call
+ *
+ *    JS_MarkGCThing(cx, thing, name, arg);
+ *
+ * The trailing name and arg parameters are used for GC_MARK_DEBUG-mode heap
+ * dumping and ref-path tracing.  The mark function should pass a (typically
+ * literal) string naming the private data member for name, and it must pass
+ * the opaque arg parameter through from its caller.
  *
  * For the JSObjectOps.mark hook, the return value is the number of slots at
  * obj->slots to scan.  For JSClass.mark, the return value is ignored.