[json] support replacer function in BasicJsonStringifier.

src/json-stringifier.cc

Index: src/json-stringifier.cc
diff --git a/src/json-stringifier.cc b/src/json-stringifier.cc
index 955b7e3c222eedd210ba6ac9f294797382e66663..b7059d6f110482ec9a8d06466a2a7114840e984b 100644
--- a/src/json-stringifier.cc
+++ b/src/json-stringifier.cc
@@ -15,7 +15,7 @@ namespace internal {
 
 // Translation table to escape Latin1 characters.
 // Table entries start at a multiple of 8 and are null-terminated.
-const char* const BasicJsonStringifier::JsonEscapeTable =
+const char* const JsonStringifier::JsonEscapeTable =
     "\\u0000\0 \\u0001\0 \\u0002\0 \\u0003\0 "
     "\\u0004\0 \\u0005\0 \\u0006\0 \\u0007\0 "
     "\\b\0     \\t\0     \\n\0     \\u000b\0 "
@@ -81,15 +81,15 @@ const char* const BasicJsonStringifier::JsonEscapeTable =
     "\370\0      \371\0      \372\0      \373\0      "
     "\374\0      \375\0      \376\0      \377\0      ";
 
-BasicJsonStringifier::BasicJsonStringifier(Isolate* isolate)
+JsonStringifier::JsonStringifier(Isolate* isolate)
     : isolate_(isolate), builder_(isolate), gap_(nullptr), indent_(0) {
   tojson_string_ = factory()->toJSON_string();
   stack_ = factory()->NewJSArray(8);
 }
 
-MaybeHandle<Object> BasicJsonStringifier::Stringify(Handle<Object> object,
-                                                    Handle<Object> replacer,
-                                                    Handle<Object> gap) {
+MaybeHandle<Object> JsonStringifier::Stringify(Handle<Object> object,
+                                               Handle<Object> replacer,
+                                               Handle<Object> gap) {
   if (!InitializeReplacer(replacer)) return MaybeHandle<Object>();
   if (!gap->IsUndefined() && !InitializeGap(gap)) return MaybeHandle<Object>();
   Result result = SerializeObject(object);
@@ -108,8 +108,9 @@ bool IsInList(Handle<String> key, List<Handle<String> >* list) {
   return false;
 }
 
-bool BasicJsonStringifier::InitializeReplacer(Handle<Object> replacer) {
+bool JsonStringifier::InitializeReplacer(Handle<Object> replacer) {
   DCHECK(property_list_.is_null());
+  DCHECK(replacer_function_.is_null());
   Maybe<bool> is_array = Object::IsArray(replacer);
   if (is_array.IsNothing()) return false;
   if (is_array.FromJust()) {
@@ -144,11 +145,13 @@ bool BasicJsonStringifier::InitializeReplacer(Handle<Object> replacer) {
       property_list_->set(i, *list[i]);
     }
     property_list_ = handle_scope.CloseAndEscape(property_list_);
+  } else if (replacer->IsCallable()) {
+    replacer_function_ = Handle<JSReceiver>::cast(replacer);
   }
   return true;
 }
 
-bool BasicJsonStringifier::InitializeGap(Handle<Object> gap) {
+bool JsonStringifier::InitializeGap(Handle<Object> gap) {
   DCHECK_NULL(gap_);
   HandleScope scope(isolate_);
   if (gap->IsJSValue()) {
@@ -188,49 +191,9 @@ bool BasicJsonStringifier::InitializeGap(Handle<Object> gap) {
   return true;
 }
 
-MaybeHandle<Object> BasicJsonStringifier::StringifyString(
-    Isolate* isolate, Handle<String> object) {
-  static const int kJsonQuoteWorstCaseBlowup = 6;
-  static const int kSpaceForQuotes = 2;
-  int worst_case_length =
-      object->length() * kJsonQuoteWorstCaseBlowup + kSpaceForQuotes;
-
-  if (worst_case_length > 32 * KB) {  // Slow path if too large.
-    BasicJsonStringifier stringifier(isolate);
-    Handle<Object> undefined = isolate->factory()->undefined_value();
-    return stringifier.Stringify(object, undefined, undefined);
-  }
-
-  object = String::Flatten(object);
-  DCHECK(object->IsFlat());
-  Handle<SeqString> result;
-  if (object->IsOneByteRepresentationUnderneath()) {
-    result = isolate->factory()
-                 ->NewRawOneByteString(worst_case_length)
-                 .ToHandleChecked();
-    IncrementalStringBuilder::NoExtendString<uint8_t> no_extend(
-        result, worst_case_length);
-    no_extend.Append('\"');
-    SerializeStringUnchecked_(object->GetFlatContent().ToOneByteVector(),
-                              &no_extend);
-    no_extend.Append('\"');
-    return no_extend.Finalize();
-  } else {
-    result = isolate->factory()
-                 ->NewRawTwoByteString(worst_case_length)
-                 .ToHandleChecked();
-    IncrementalStringBuilder::NoExtendString<uc16> no_extend(result,
-                                                             worst_case_length);
-    no_extend.Append('\"');
-    SerializeStringUnchecked_(object->GetFlatContent().ToUC16Vector(),
-                              &no_extend);
-    no_extend.Append('\"');
-    return no_extend.Finalize();
-  }
-}
-
-MaybeHandle<Object> BasicJsonStringifier::ApplyToJsonFunction(
-    Handle<Object> object, Handle<Object> key) {
+MaybeHandle<Object> JsonStringifier::ApplyToJsonFunction(Handle<Object> object,
+                                                         Handle<Object> key) {
+  HandleScope scope(isolate_);
   LookupIterator it(object, tojson_string_,
                     LookupIterator::PROTOTYPE_CHAIN_SKIP_INTERCEPTOR);
   Handle<Object> fun;
@@ -240,15 +203,39 @@ MaybeHandle<Object> BasicJsonStringifier::ApplyToJsonFunction(
   // Call toJSON function.
   if (key->IsSmi()) key = factory()->NumberToString(key);
   Handle<Object> argv[] = {key};
-  HandleScope scope(isolate_);
   ASSIGN_RETURN_ON_EXCEPTION(isolate_, object,
                              Execution::Call(isolate_, fun, object, 1, argv),
                              Object);
   return scope.CloseAndEscape(object);
 }
 
-BasicJsonStringifier::Result BasicJsonStringifier::StackPush(
-    Handle<Object> object) {
+MaybeHandle<Object> JsonStringifier::ApplyReplacerFunction(
+    Handle<Object> object, Handle<Object> key) {
+  HandleScope scope(isolate_);
+  if (key->IsSmi()) key = factory()->NumberToString(key);
+  Handle<Object> argv[] = {key, object};
+  Handle<JSReceiver> holder = CurrentHolder(object);
+  ASSIGN_RETURN_ON_EXCEPTION(
+      isolate_, object,
+      Execution::Call(isolate_, replacer_function_, holder, 2, argv), Object);
+  return scope.CloseAndEscape(object);
+}
+
+Handle<JSReceiver> JsonStringifier::CurrentHolder(Handle<Object> value) {
+  int length = Smi::cast(stack_->length())->value();
+  if (length == 0) {
+    Handle<JSObject> holder =
+        factory()->NewJSObject(isolate_->object_function());
+    JSObject::AddProperty(holder, factory()->empty_string(), value, NONE);
+    return holder;
+  } else {
+    FixedArray* elements = FixedArray::cast(stack_->elements());
+    return Handle<JSReceiver>(JSReceiver::cast(elements->get(length - 1)),
+                              isolate_);
+  }
+}
+
+JsonStringifier::Result JsonStringifier::StackPush(Handle<Object> object) {
   StackLimitCheck check(isolate_);
   if (check.HasOverflowed()) {
     isolate_->StackOverflow();
@@ -274,18 +261,23 @@ BasicJsonStringifier::Result BasicJsonStringifier::StackPush(
   return SUCCESS;
 }
 
-void BasicJsonStringifier::StackPop() {
+void JsonStringifier::StackPop() {
   int length = Smi::cast(stack_->length())->value();
   stack_->set_length(Smi::FromInt(length - 1));
 }
 
 template <bool deferred_string_key>
-BasicJsonStringifier::Result BasicJsonStringifier::Serialize_(
-    Handle<Object> object, bool comma, Handle<Object> key) {
+JsonStringifier::Result JsonStringifier::Serialize_(Handle<Object> object,
+                                                    bool comma,
+                                                    Handle<Object> key) {
   if (object->IsJSReceiver()) {
     ASSIGN_RETURN_ON_EXCEPTION_VALUE(
         isolate_, object, ApplyToJsonFunction(object, key), EXCEPTION);
   }
+  if (!replacer_function_.is_null()) {
+    ASSIGN_RETURN_ON_EXCEPTION_VALUE(
+        isolate_, object, ApplyReplacerFunction(object, key), EXCEPTION);
+  }
 
   if (object->IsSmi()) {
     if (deferred_string_key) SerializeDeferredKey(comma, key);
@@ -344,7 +336,7 @@ BasicJsonStringifier::Result BasicJsonStringifier::Serialize_(
   return UNCHANGED;
 }
 
-BasicJsonStringifier::Result BasicJsonStringifier::SerializeJSValue(
+JsonStringifier::Result JsonStringifier::SerializeJSValue(
     Handle<JSValue> object) {
   String* class_name = object->class_name();
   if (class_name == isolate_->heap()->String_string()) {
@@ -369,7 +361,7 @@ BasicJsonStringifier::Result BasicJsonStringifier::SerializeJSValue(
   return SUCCESS;
 }
 
-BasicJsonStringifier::Result BasicJsonStringifier::SerializeSmi(Smi* object) {
+JsonStringifier::Result JsonStringifier::SerializeSmi(Smi* object) {
   static const int kBufferSize = 100;
   char chars[kBufferSize];
   Vector<char> buffer(chars, kBufferSize);
@@ -377,8 +369,7 @@ BasicJsonStringifier::Result BasicJsonStringifier::SerializeSmi(Smi* object) {
   return SUCCESS;
 }
 
-BasicJsonStringifier::Result BasicJsonStringifier::SerializeDouble(
-    double number) {
+JsonStringifier::Result JsonStringifier::SerializeDouble(double number) {
   if (std::isinf(number) || std::isnan(number)) {
     builder_.AppendCString("null");
     return SUCCESS;
@@ -390,7 +381,7 @@ BasicJsonStringifier::Result BasicJsonStringifier::SerializeDouble(
   return SUCCESS;
 }
 
-BasicJsonStringifier::Result BasicJsonStringifier::SerializeJSArray(
+JsonStringifier::Result JsonStringifier::SerializeJSArray(
     Handle<JSArray> object) {
   HandleScope handle_scope(isolate_);
   Result stack_push = StackPush(object);
@@ -400,59 +391,65 @@ BasicJsonStringifier::Result BasicJsonStringifier::SerializeJSArray(
   DCHECK(!object->IsAccessCheckNeeded());
   builder_.AppendCharacter('[');
   Indent();
-  switch (object->GetElementsKind()) {
-    case FAST_SMI_ELEMENTS: {
-      Handle<FixedArray> elements(FixedArray::cast(object->elements()),
-                                  isolate_);
-      for (uint32_t i = 0; i < length; i++) {
-        Separator(i == 0);
-        SerializeSmi(Smi::cast(elements->get(i)));
-      }
-      break;
-    }
-    case FAST_DOUBLE_ELEMENTS: {
-      // Empty array is FixedArray but not FixedDoubleArray.
-      if (length == 0) break;
-      Handle<FixedDoubleArray> elements(
-          FixedDoubleArray::cast(object->elements()), isolate_);
-      for (uint32_t i = 0; i < length; i++) {
-        Separator(i == 0);
-        SerializeDouble(elements->get_scalar(i));
+  uint32_t i = 0;
+  if (replacer_function_.is_null()) {
+    switch (object->GetElementsKind()) {
+      case FAST_SMI_ELEMENTS: {
+        Handle<FixedArray> elements(FixedArray::cast(object->elements()),
+                                    isolate_);
+        while (i < length) {
+          Separator(i == 0);
+          SerializeSmi(Smi::cast(elements->get(i)));
+          i++;
+        }
+        break;
       }
-      break;
-    }
-    case FAST_ELEMENTS: {
-      Handle<Object> old_length(object->length(), isolate_);
-      for (uint32_t i = 0; i < length; i++) {
-        if (object->length() != *old_length ||
-            object->GetElementsKind() != FAST_ELEMENTS) {
-          Result result = SerializeArrayLikeSlow(object, i, length);
-          if (result != SUCCESS) return result;
-          break;
+      case FAST_DOUBLE_ELEMENTS: {
+        // Empty array is FixedArray but not FixedDoubleArray.
+        if (length == 0) break;
+        Handle<FixedDoubleArray> elements(
+            FixedDoubleArray::cast(object->elements()), isolate_);
+        while (i < length) {
+          Separator(i == 0);
+          SerializeDouble(elements->get_scalar(i));
+          i++;
         }
-        Separator(i == 0);
-        Result result = SerializeElement(
-            isolate_,
-            Handle<Object>(FixedArray::cast(object->elements())->get(i),
-                           isolate_),
-            i);
-        if (result == SUCCESS) continue;
-        if (result == UNCHANGED) {
-          builder_.AppendCString("null");
-        } else {
-          return result;
+        break;
+      }
+      case FAST_ELEMENTS: {
+        Handle<Object> old_length(object->length(), isolate_);
+        while (i < length) {
+          if (object->length() != *old_length ||
+              object->GetElementsKind() != FAST_ELEMENTS) {
+            // Fall back to slow path.
+            break;
+          }
+          Separator(i == 0);
+          Result result = SerializeElement(
+              isolate_,
+              Handle<Object>(FixedArray::cast(object->elements())->get(i),
+                             isolate_),
+              i);
+          if (result == UNCHANGED) {
+            builder_.AppendCString("null");
+          } else if (result != SUCCESS) {
+            return result;
+          }
+          i++;
         }
+        break;
       }
-      break;
-    }
-    // The FAST_HOLEY_* cases could be handled in a faster way. They resemble
-    // the non-holey cases except that a lookup is necessary for holes.
-    default: {
-      Result result = SerializeArrayLikeSlow(object, 0, length);
-      if (result != SUCCESS) return result;
-      break;
+      // The FAST_HOLEY_* cases could be handled in a faster way. They resemble
+      // the non-holey cases except that a lookup is necessary for holes.
+      default:
+        break;
     }
   }
+  if (i < length) {
+    // Slow path for non-fast elements and fall-back in edge case.
+    Result result = SerializeArrayLikeSlow(object, i, length);
+    if (result != SUCCESS) return result;
+  }
   Unindent();
   if (length > 0) NewLine();
   builder_.AppendCharacter(']');
@@ -460,7 +457,7 @@ BasicJsonStringifier::Result BasicJsonStringifier::SerializeJSArray(
   return SUCCESS;
 }
 
-BasicJsonStringifier::Result BasicJsonStringifier::SerializeArrayLikeSlow(
+JsonStringifier::Result JsonStringifier::SerializeArrayLikeSlow(
     Handle<JSReceiver> object, uint32_t start, uint32_t length) {
   for (uint32_t i = start; i < length; i++) {
     Separator(i == 0);
@@ -468,22 +465,18 @@ BasicJsonStringifier::Result BasicJsonStringifier::SerializeArrayLikeSlow(
     ASSIGN_RETURN_ON_EXCEPTION_VALUE(
         isolate_, element, JSReceiver::GetElement(isolate_, object, i),
         EXCEPTION);
-    if (element->IsUndefined()) {
+    Result result = SerializeElement(isolate_, element, i);
+    if (result == SUCCESS) continue;
+    if (result == UNCHANGED) {
       builder_.AppendCString("null");
     } else {
-      Result result = SerializeElement(isolate_, element, i);
-      if (result == SUCCESS) continue;
-      if (result == UNCHANGED) {
-        builder_.AppendCString("null");
-      } else {
-        return result;
-      }
+      return result;
     }
   }
   return SUCCESS;
 }
 
-BasicJsonStringifier::Result BasicJsonStringifier::SerializeJSObject(
+JsonStringifier::Result JsonStringifier::SerializeJSObject(
     Handle<JSObject> object) {
   HandleScope handle_scope(isolate_);
   Result stack_push = StackPush(object);
@@ -512,12 +505,8 @@ BasicJsonStringifier::Result BasicJsonStringifier::SerializeJSObject(
       Handle<Object> property;
       if (details.type() == DATA && *map == js_obj->map()) {
         FieldIndex field_index = FieldIndex::ForDescriptor(*map, i);
-        if (js_obj->IsUnboxedDoubleField(field_index)) {
-          double value = js_obj->RawFastDoublePropertyAt(field_index);
-          property = isolate_->factory()->NewHeapNumber(value);
-        } else {
-          property = handle(js_obj->RawFastPropertyAt(field_index), isolate_);
-        }
+        property = JSObject::FastPropertyAt(js_obj, details.representation(),
+                                            field_index);
       } else {
         ASSIGN_RETURN_ON_EXCEPTION_VALUE(
             isolate_, property, Object::GetPropertyOrElement(js_obj, key),
@@ -538,7 +527,7 @@ BasicJsonStringifier::Result BasicJsonStringifier::SerializeJSObject(
   return SUCCESS;
 }
 
-BasicJsonStringifier::Result BasicJsonStringifier::SerializeJSReceiverSlow(
+JsonStringifier::Result JsonStringifier::SerializeJSReceiverSlow(
     Handle<JSReceiver> object) {
   Handle<FixedArray> contents = property_list_;
   if (contents.is_null()) {
@@ -580,7 +569,7 @@ BasicJsonStringifier::Result BasicJsonStringifier::SerializeJSReceiverSlow(
   return SUCCESS;
 }
 
-BasicJsonStringifier::Result BasicJsonStringifier::SerializeJSProxy(
+JsonStringifier::Result JsonStringifier::SerializeJSProxy(
     Handle<JSProxy> object) {
   Result stack_push = StackPush(object);
   if (stack_push != SUCCESS) return stack_push;
@@ -615,7 +604,7 @@ BasicJsonStringifier::Result BasicJsonStringifier::SerializeJSProxy(
 }
 
 template <typename SrcChar, typename DestChar>
-void BasicJsonStringifier::SerializeStringUnchecked_(
+void JsonStringifier::SerializeStringUnchecked_(
     Vector<const SrcChar> src,
     IncrementalStringBuilder::NoExtend<DestChar>* dest) {
   // Assert that uc16 character is not truncated down to 8 bit.
@@ -633,7 +622,7 @@ void BasicJsonStringifier::SerializeStringUnchecked_(
 }
 
 template <typename SrcChar, typename DestChar>
-void BasicJsonStringifier::SerializeString_(Handle<String> string) {
+void JsonStringifier::SerializeString_(Handle<String> string) {
   int length = string->length();
   builder_.Append<uint8_t, DestChar>('"');
   // We make a rough estimate to find out if the current string can be
@@ -663,35 +652,35 @@ void BasicJsonStringifier::SerializeString_(Handle<String> string) {
 }
 
 template <>
-bool BasicJsonStringifier::DoNotEscape(uint8_t c) {
+bool JsonStringifier::DoNotEscape(uint8_t c) {
   return c >= '#' && c <= '~' && c != '\\';
 }
 
 template <>
-bool BasicJsonStringifier::DoNotEscape(uint16_t c) {
+bool JsonStringifier::DoNotEscape(uint16_t c) {
   return c >= '#' && c != '\\' && c != 0x7f;
 }
 
-void BasicJsonStringifier::NewLine() {
+void JsonStringifier::NewLine() {
   if (gap_ == nullptr) return;
   builder_.AppendCharacter('\n');
   for (int i = 0; i < indent_; i++) builder_.AppendCString(gap_);
 }
 
-void BasicJsonStringifier::Separator(bool first) {
+void JsonStringifier::Separator(bool first) {
   if (!first) builder_.AppendCharacter(',');
   NewLine();
 }
 
-void BasicJsonStringifier::SerializeDeferredKey(bool deferred_comma,
-                                                Handle<Object> deferred_key) {
+void JsonStringifier::SerializeDeferredKey(bool deferred_comma,
+                                           Handle<Object> deferred_key) {
   Separator(!deferred_comma);
   SerializeString(Handle<String>::cast(deferred_key));
   builder_.AppendCharacter(':');
   if (gap_ != nullptr) builder_.AppendCharacter(' ');
 }
 
-void BasicJsonStringifier::SerializeString(Handle<String> object) {
+void JsonStringifier::SerializeString(Handle<String> object) {
   object = String::Flatten(object);
   if (builder_.CurrentEncoding() == String::ONE_BYTE_ENCODING) {
     if (object->IsOneByteRepresentationUnderneath()) {