From 2a47d8d6eef22d117ac3475e84c3a52b5ca41a3c Mon Sep 17 00:00:00 2001
From: Jochen Eisinger <jochen@chromium.org>
Date: Wed, 13 May 2015 02:31:02 +0200
Subject: Set pointers in internal fields directly instead of wrapping them

The internal fields are scanned by the garbage collector, so they can't contain arbitrary data. However, aligned pointers are supported by the V8 GC, so the V8
API allows for setting a pointer directly instead of wrapping it in an External
container.

Not only is this faster, but it's also required for the new v8::Global API which
I'm going to update to in a follow-up patch.

R=tsepez@chromium.org
BUG=

Review URL: https://codereview.chromium.org/1139853003
---
 fpdfsdk/src/jsapi/fxjs_v8.cpp | 28 +++++++++-------------------
 1 file changed, 9 insertions(+), 19 deletions(-)

diff --git a/fpdfsdk/src/jsapi/fxjs_v8.cpp b/fpdfsdk/src/jsapi/fxjs_v8.cpp
index c55c092d17..7af8237c2e 100644
--- a/fpdfsdk/src/jsapi/fxjs_v8.cpp
+++ b/fpdfsdk/src/jsapi/fxjs_v8.cpp
@@ -265,9 +265,8 @@ void JS_InitialRuntime(IJS_Runtime* pJSRuntime,IFXJS_Runtime* pFXRuntime, IFXJS_
 
 				CJS_PrivateData* pPrivateData = new CJS_PrivateData;
 				pPrivateData->ObjDefID = i;
-				v8::Handle<v8::External> ptr = v8::External::New(isolate, pPrivateData);
 
-				v8Context->Global()->GetPrototype()->ToObject()->SetInternalField(0, ptr); 
+				v8Context->Global()->GetPrototype()->ToObject()->SetAlignedPointerInInternalField(0, pPrivateData);
 
 				if(pObjDef->m_pConstructor)
 					pObjDef->m_pConstructor(context, v8Context->Global()->GetPrototype()->ToObject(), v8Context->Global()->GetPrototype()->ToObject());
@@ -382,8 +381,7 @@ v8::Handle<v8::Object> JS_NewFxDynamicObj(IJS_Runtime* pJSRuntime, IFXJS_Context
 	CJS_PrivateData* pPrivateData = new CJS_PrivateData;
 	pPrivateData->ObjDefID = nObjDefnID;
 
-	v8::Handle<v8::External> ptr = v8::External::New(isolate, pPrivateData);
-	obj->SetInternalField(0, ptr);
+	obj->SetAlignedPointerInInternalField(0, pPrivateData);
 	if(pObjDef->m_pConstructor)
 		pObjDef->m_pConstructor(pJSContext, obj, context->Global()->GetPrototype()->ToObject());
 
@@ -424,8 +422,7 @@ v8::Handle<v8::Object>	JS_GetThisObj(IJS_Runtime * pJSRuntime)
 int	JS_GetObjDefnID(v8::Handle<v8::Object> pObj)
 {
 	if(pObj.IsEmpty() || !pObj->InternalFieldCount()) return -1;
-	v8::Handle<v8::External> field = v8::Handle<v8::External>::Cast(pObj->GetInternalField(0));
-	CJS_PrivateData* pPrivateData = (CJS_PrivateData*)field->Value();
+	CJS_PrivateData* pPrivateData = (CJS_PrivateData*)pObj->GetAlignedPointerFromInternalField(0);
 	if(pPrivateData)
 		return pPrivateData->ObjDefID;
 	return -1;
@@ -508,8 +505,7 @@ void* JS_GetPrivate(v8::Handle<v8::Object> pObj)
 void JS_SetPrivate(IJS_Runtime* pJSRuntime, v8::Handle<v8::Object> pObj, void* p)
 {
 	if(pObj.IsEmpty() || !pObj->InternalFieldCount()) return;
-	v8::Handle<v8::External> ptr = v8::Handle<v8::External>::Cast(pObj->GetInternalField(0));
-	CJS_PrivateData* pPrivateData  = (CJS_PrivateData*)ptr->Value();
+	CJS_PrivateData* pPrivateData  = (CJS_PrivateData*)pObj->GetAlignedPointerFromInternalField(0);
 	if(!pPrivateData) return;
 	pPrivateData->pPrivate = p;
 }
@@ -517,19 +513,16 @@ void JS_SetPrivate(IJS_Runtime* pJSRuntime, v8::Handle<v8::Object> pObj, void* p
 void* JS_GetPrivate(IJS_Runtime* pJSRuntime, v8::Handle<v8::Object> pObj)
 {
 	if(pObj.IsEmpty()) return NULL;
-	v8::Local<v8::Value> value;
+	CJS_PrivateData* pPrivateData  = NULL;
 	if(pObj->InternalFieldCount())
-		value = pObj->GetInternalField(0); 
+                pPrivateData = (CJS_PrivateData*)pObj->GetAlignedPointerFromInternalField(0);
 	else
 	{
 		//It could be a global proxy object.
 		v8::Local<v8::Value> v = pObj->GetPrototype();
 		if(v->IsObject())
-			value = v->ToObject()->GetInternalField(0);
+                        pPrivateData = (CJS_PrivateData*)v->ToObject()->GetAlignedPointerFromInternalField(0);
 	}
-	if(value.IsEmpty() || value->IsUndefined()) return NULL;
-	v8::Handle<v8::External> ptr = v8::Handle<v8::External>::Cast(value);
-	CJS_PrivateData* pPrivateData  = (CJS_PrivateData*)ptr->Value();
 	if(!pPrivateData) return NULL;
 	return pPrivateData->pPrivate;
 }
@@ -537,11 +530,8 @@ void* JS_GetPrivate(IJS_Runtime* pJSRuntime, v8::Handle<v8::Object> pObj)
 void JS_FreePrivate(v8::Handle<v8::Object> pObj)
 {
 	if(pObj.IsEmpty() || !pObj->InternalFieldCount()) return;
-	v8::Handle<v8::External> ptr = v8::Handle<v8::External>::Cast(pObj->GetInternalField(0));
-	delete (CJS_PrivateData*)ptr->Value();
-	v8::Local<v8::Context> context = pObj->CreationContext();
-
-	pObj->SetInternalField(0, v8::External::New(context->GetIsolate(), NULL));
+	delete (CJS_PrivateData*)pObj->GetAlignedPointerFromInternalField(0);
+	pObj->SetAlignedPointerInInternalField(0, NULL);
 }
 
 
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