Make NewNull return an actual Null

This CL updates the CFXJS_Engine::NewNull method to return a real v8::Null
instead of an empty v8::Local. This also adds a NewUndefined and returns
undefined in most of the places null was returned previously.

Change-Id: If1a96bf253057892a3b709cbc72f8825c52503c3
Reviewed-on: https://pdfium-review.googlesource.com/16730
Reviewed-by: Tom Sepez <tsepez@chromium.org>
Commit-Queue: dsinclair <dsinclair@chromium.org>

8 files changed, 32 insertions, 16 deletions

diff --git a/fpdfsdk/javascript/Document.cpp b/fpdfsdk/javascript/Document.cpp
index 9404ded0c8..2217f448f2 100644
--- a/fpdfsdk/javascript/Document.cpp
+++ b/fpdfsdk/javascript/Document.cpp
@@ -213,7 +213,7 @@ bool Document::set_dirty(CJS_Runtime* pRuntime,
 bool Document::get_ADBE(CJS_Runtime* pRuntime,
                         CJS_Value* vp,
                         WideString* sError) {
-  vp->Set(pRuntime->NewNull());
+  vp->Set(pRuntime->NewUndefined());
   return true;
 }
 
@@ -312,7 +312,7 @@ bool Document::getField(CJS_Runtime* pRuntime,
   CPDFSDK_InterForm* pInterForm = m_pFormFillEnv->GetInterForm();
   CPDF_InterForm* pPDFForm = pInterForm->GetInterForm();
   if (pPDFForm->CountFields(wideName) <= 0) {
-    vRet.Set(pRuntime->NewNull());
+    vRet.Set(pRuntime->NewUndefined());
     return true;
   }
 
@@ -1321,7 +1321,7 @@ bool Document::getAnnot3D(CJS_Runtime* pRuntime,
                           const std::vector<v8::Local<v8::Value>>& params,
                           CJS_Value& vRet,
                           WideString& sError) {
-  vRet.Set(pRuntime->NewNull());
+  vRet.Set(pRuntime->NewUndefined());
   return true;
 }
 
@@ -1387,7 +1387,7 @@ bool Document::get_icons(CJS_Runtime* pRuntime,
                          CJS_Value* vp,
                          WideString* sError) {
   if (m_IconNames.empty()) {
-    vp->Set(pRuntime->NewNull());
+    vp->Set(pRuntime->NewUndefined());
     return true;
   }
 
diff --git a/fpdfsdk/javascript/PublicMethods.cpp b/fpdfsdk/javascript/PublicMethods.cpp
index c0441a82a3..667127fe88 100644
--- a/fpdfsdk/javascript/PublicMethods.cpp
+++ b/fpdfsdk/javascript/PublicMethods.cpp
@@ -1840,7 +1840,7 @@ bool CJS_PublicMethods::AFExtractNums(
     else
       vRet = CJS_Value(nums.ToV8Value());
   } else {
-    vRet.Set(pRuntime->NewNull());
+    vRet.Set(pRuntime->NewUndefined());
   }
 
   return true;
diff --git a/fpdfsdk/javascript/app.cpp b/fpdfsdk/javascript/app.cpp
index ca440f64b3..cbc3145b0f 100644
--- a/fpdfsdk/javascript/app.cpp
+++ b/fpdfsdk/javascript/app.cpp
@@ -237,7 +237,7 @@ bool app::get_active_docs(CJS_Runtime* pRuntime,
     else
       vp->Set(aDocs.ToV8Value());
   } else {
-    vp->Set(pRuntime->NewNull());
+    vp->Set(pRuntime->NewUndefined());
   }
 
   return true;
diff --git a/fpdfsdk/javascript/global.cpp b/fpdfsdk/javascript/global.cpp
index 040c6e6067..5dc6ac9d78 100644
--- a/fpdfsdk/javascript/global.cpp
+++ b/fpdfsdk/javascript/global.cpp
@@ -109,7 +109,8 @@ void JSSpecialPropGet(const char* class_name,
     pRuntime->Error(JSFormatErrorString(class_name, "GetProperty", L""));
     return;
   }
-  info.GetReturnValue().Set(value.ToV8Value());
+  if (!value.ToV8Value().IsEmpty())
+    info.GetReturnValue().Set(value.ToV8Value());
 }
 
 template <class Alt>
@@ -284,16 +285,12 @@ bool JSGlobalAlternate::GetProperty(CJS_Runtime* pRuntime,
                                     const wchar_t* propname,
                                     CJS_Value* vp) {
   auto it = m_MapGlobal.find(ByteString::FromUnicode(propname));
-  if (it == m_MapGlobal.end()) {
-    vp->Set(pRuntime->NewNull());
+  if (it == m_MapGlobal.end())
     return true;
-  }
 
   JSGlobalData* pData = it->second.get();
-  if (pData->bDeleted) {
-    vp->Set(pRuntime->NewNull());
+  if (pData->bDeleted)
     return true;
-  }
 
   switch (pData->nType) {
     case JS_GlobalDataType::NUMBER:
diff --git a/fpdfsdk/javascript/util.cpp b/fpdfsdk/javascript/util.cpp
index ecec8d173d..202a1ead7f 100644
--- a/fpdfsdk/javascript/util.cpp
+++ b/fpdfsdk/javascript/util.cpp
@@ -398,7 +398,7 @@ bool util::scand(CJS_Runtime* pRuntime,
   if (!std::isnan(dDate)) {
     vRet = CJS_Value(CJS_Date(pRuntime, dDate).ToV8Value());
   } else {
-    vRet.Set(pRuntime->NewNull());
+    vRet.Set(pRuntime->NewUndefined());
   }
 
   return true;
diff --git a/fxjs/fxjs_v8.cpp b/fxjs/fxjs_v8.cpp
index 4c6398870d..441848205f 100644
--- a/fxjs/fxjs_v8.cpp
+++ b/fxjs/fxjs_v8.cpp
@@ -664,7 +664,11 @@ v8::Local<v8::String> CFXJS_Engine::NewString(const WideStringView& str) {
 }
 
 v8::Local<v8::Value> CFXJS_Engine::NewNull() {
-  return v8::Local<v8::Value>();
+  return v8::Null(m_isolate);
+}
+
+v8::Local<v8::Value> CFXJS_Engine::NewUndefined() {
+  return v8::Undefined(m_isolate);
 }
 
 v8::Local<v8::Date> CFXJS_Engine::NewDate(double d) {
diff --git a/fxjs/fxjs_v8.h b/fxjs/fxjs_v8.h
index f5e52411f3..eee85e031d 100644
--- a/fxjs/fxjs_v8.h
+++ b/fxjs/fxjs_v8.h
@@ -179,6 +179,7 @@ class CFXJS_Engine {
   v8::Local<v8::Object> GetThisObj();
 
   v8::Local<v8::Value> NewNull();
+  v8::Local<v8::Value> NewUndefined();
   v8::Local<v8::Array> NewArray();
   v8::Local<v8::Number> NewNumber(int number);
   v8::Local<v8::Number> NewNumber(double number);
diff --git a/fxjs/fxjs_v8_embeddertest.cpp b/fxjs/fxjs_v8_embeddertest.cpp
index 53fe8f268b..d975264d1d 100644
--- a/fxjs/fxjs_v8_embeddertest.cpp
+++ b/fxjs/fxjs_v8_embeddertest.cpp
@@ -98,11 +98,25 @@ TEST_F(FXJSV8EmbedderTest, NewNull) {
   EXPECT_FALSE(engine()->ToBoolean(nullz));
   EXPECT_EQ(0, engine()->ToInt32(nullz));
   EXPECT_EQ(0.0, engine()->ToDouble(nullz));
-  EXPECT_EQ(L"", engine()->ToWideString(nullz));
+  EXPECT_EQ(L"null", engine()->ToWideString(nullz));
   EXPECT_TRUE(engine()->ToObject(nullz).IsEmpty());
   EXPECT_TRUE(engine()->ToArray(nullz).IsEmpty());
 }
 
+TEST_F(FXJSV8EmbedderTest, NewUndefined) {
+  v8::Isolate::Scope isolate_scope(isolate());
+  v8::HandleScope handle_scope(isolate());
+  v8::Context::Scope context_scope(GetV8Context());
+
+  auto undef = engine()->NewUndefined();
+  EXPECT_FALSE(engine()->ToBoolean(undef));
+  EXPECT_EQ(0, engine()->ToInt32(undef));
+  EXPECT_TRUE(std::isnan(engine()->ToDouble(undef)));
+  EXPECT_EQ(L"undefined", engine()->ToWideString(undef));
+  EXPECT_TRUE(engine()->ToObject(undef).IsEmpty());
+  EXPECT_TRUE(engine()->ToArray(undef).IsEmpty());
+}
+
 TEST_F(FXJSV8EmbedderTest, NewBoolean) {
   v8::Isolate::Scope isolate_scope(isolate());
   v8::HandleScope handle_scope(isolate());