Bug 585786. Do fast-unwrapping even for non-slim wrappers as long as they're cached. r=peterv

content/base/src/nsContentUtils.cpp

@@ -5504,7 +5504,7 @@ nsContentUtils::WrapNative(JSContext *cx, JSObject *scope, nsISupports *native,
     return NS_OK;
   }
 
-  JSObject *wrapper = xpc_GetCachedSlimWrapper(cache, scope, vp);
+  JSObject *wrapper = xpc_FastGetCachedWrapper(cache, scope, vp);
   if (wrapper) {
     return NS_OK;
   }

dom/base/nsDOMClassInfo.cpp

@@ -4265,7 +4265,7 @@ nsDOMClassInfo::WrapNative(JSContext *cx, JSObject *scope,
     return NS_OK;
   }
 
-  JSObject *wrapper = xpc_GetCachedSlimWrapper(cache, scope, vp);
+  JSObject *wrapper = xpc_FastGetCachedWrapper(cache, scope, vp);
   if (wrapper) {
     return NS_OK;
   }

js/src/xpconnect/src/qsgen.py

@@ -722,7 +722,7 @@ def writeResultConv(f, type, jsvalPtr, jsvalRef):
             return
         else:
             f.write("    nsWrapperCache* cache = xpc_qsGetWrapperCache(result);\n"
-                    "    if (xpc_GetCachedSlimWrapper(cache, obj, %s)) {\n"
+                    "    if (xpc_FastGetCachedWrapper(cache, obj, %s)) {\n"
                     "      return JS_TRUE;\n"
                     "    }\n"
                     "    // After this point do not use 'result'!\n"
@@ -1285,7 +1285,7 @@ def writeTraceableResultConv(f, type):
         else:
             f.write("    nsWrapperCache* cache = xpc_qsGetWrapperCache(result);\n"
                     "    JSObject* wrapper =\n"
-                    "      xpc_GetCachedSlimWrapper(cache, obj);\n"
+                    "      xpc_FastGetCachedWrapper(cache, obj);\n"
                     "    if (wrapper) {\n"
                     "      return wrapper;\n"
                     "    }\n"

js/src/xpconnect/src/xpcpublic.h

@@ -113,18 +113,23 @@ xpc_GetGlobalForObject(JSObject *obj)
     return obj;
 }
 
+extern bool
+xpc_OkToHandOutWrapper(nsWrapperCache *cache);
+
 inline JSObject*
-xpc_GetCachedSlimWrapper(nsWrapperCache *cache, JSObject *scope, jsval *vp)
+xpc_FastGetCachedWrapper(nsWrapperCache *cache, JSObject *scope, jsval *vp)
 {
     if (cache) {
         JSObject* wrapper = cache->GetWrapper();
-        // FIXME: Bug 585786, the check for IS_SLIM_WRAPPER_OBJECT should go
-        //        away
+        NS_ASSERTION(!wrapper ||
+                     !cache->IsProxy() ||
+                     !IS_SLIM_WRAPPER_OBJECT(wrapper),
+                     "Should never have a slim wrapper when IsProxy()");
         if (wrapper &&
-            IS_SLIM_WRAPPER_OBJECT(wrapper) &&
-            wrapper->compartment() == scope->getCompartment()) {
+            wrapper->compartment() == scope->getCompartment() &&
+            (IS_SLIM_WRAPPER_OBJECT(wrapper) ||
+             xpc_OkToHandOutWrapper(cache))) {
             *vp = OBJECT_TO_JSVAL(wrapper);
-
             return wrapper;
         }
     }
@@ -133,10 +138,10 @@ xpc_GetCachedSlimWrapper(nsWrapperCache *cache, JSObject *scope, jsval *vp)
 }
 
 inline JSObject*
-xpc_GetCachedSlimWrapper(nsWrapperCache *cache, JSObject *scope)
+xpc_FastGetCachedWrapper(nsWrapperCache *cache, JSObject *scope)
 {
     jsval dummy;
-    return xpc_GetCachedSlimWrapper(cache, scope, &dummy);
+    return xpc_FastGetCachedWrapper(cache, scope, &dummy);
 }
 
 // The JS GC marks objects gray that are held alive directly or indirectly

js/src/xpconnect/src/xpcwrappednative.cpp

@@ -53,6 +53,18 @@
 #include "AccessCheck.h"
 #include "WrapperFactory.h"
 
+bool
+xpc_OkToHandOutWrapper(nsWrapperCache *cache)
+{
+    NS_ABORT_IF_FALSE(cache->GetWrapper(), "Must have wrapper");
+    NS_ABORT_IF_FALSE(cache->IsProxy() || IS_WN_WRAPPER(cache->GetWrapper()),
+                      "Must have proxy or XPCWrappedNative wrapper");
+    return
+        !cache->IsProxy() &&
+        !static_cast<XPCWrappedNative*>(xpc_GetJSPrivate(cache->GetWrapper()))->
+                    NeedsSOW();
+}
+
 /***************************************************************************/
 
 NS_IMPL_CYCLE_COLLECTION_CLASS(XPCWrappedNative)