bindings: Make the sequence conversion code more complaint with WebIDL.

third_party/WebKit/Source/bindings/core/v8/V8Binding.h

 /*
 * Copyright (C) 2009 Google Inc. All rights reserved.
 * Copyright (C) 2012 Ericsson AB. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 *
 *     * Redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer.
@@ skipping 641 matching lines @@
 NodeFilter* ToNodeFilter(v8::Local<v8::Value>,
                          v8::Local<v8::Object>,
                          ScriptState*);
 XPathNSResolver* ToXPathNSResolver(ScriptState*, v8::Local<v8::Value>);
 
 bool ToV8Sequence(v8::Local<v8::Value>,
                   uint32_t& length,
                   v8::Isolate*,
                   ExceptionState&);
 
-template <typename T>
-HeapVector<Member<T>> ToMemberNativeArray(v8::Local<v8::Value> value,
-                                          int argument_index,
-                                          v8::Isolate* isolate,
-                                          ExceptionState& exception_state) {
-  v8::Local<v8::Value> v8_value(v8::Local<v8::Value>::New(isolate, value));
-  uint32_t length = 0;
-  if (value->IsArray()) {
-    length = v8::Local<v8::Array>::Cast(v8_value)->Length();
-  } else if (!ToV8Sequence(value, length, isolate, exception_state)) {
-    if (!exception_state.HadException())
-      exception_state.ThrowTypeError(
-          ExceptionMessages::NotAnArrayTypeArgumentOrValue(argument_index));
-    return HeapVector<Member<T>>();
-  }
-
-  using VectorType = HeapVector<Member<T>>;
-  if (length > VectorType::MaxCapacity()) {
-    exception_state.ThrowRangeError("Array length exceeds supported limit.");
-    return VectorType();
-  }
-
-  VectorType result;
-  result.ReserveInitialCapacity(length);
-  v8::Local<v8::Object> object = v8::Local<v8::Object>::Cast(v8_value);
-  v8::TryCatch block(isolate);
-  for (uint32_t i = 0; i < length; ++i) {
-    v8::Local<v8::Value> element;
-    if (!V8Call(object->Get(isolate->GetCurrentContext(), i), element, block)) {
-      exception_state.RethrowV8Exception(block.Exception());
-      return VectorType();
-    }
-    if (V8TypeOf<T>::Type::hasInstance(element, isolate)) {
-      v8::Local<v8::Object> element_object =
-          v8::Local<v8::Object>::Cast(element);
-      result.UncheckedAppend(V8TypeOf<T>::Type::toImpl(element_object));
-    } else {
-      exception_state.ThrowTypeError("Invalid Array element type");
-      return VectorType();
-    }
-  }
-  return result;
-}
-
-template <typename T>
-HeapVector<Member<T>> ToMemberNativeArray(v8::Local<v8::Value> value,
-                                          const String& property_name,
-                                          v8::Isolate* isolate,
-                                          ExceptionState& exception_state) {
-  v8::Local<v8::Value> v8_value(v8::Local<v8::Value>::New(isolate, value));
-  uint32_t length = 0;
-  if (value->IsArray()) {
-    length = v8::Local<v8::Array>::Cast(v8_value)->Length();
-  } else if (!ToV8Sequence(value, length, isolate, exception_state)) {
-    if (!exception_state.HadException())
-      exception_state.ThrowTypeError(
-          ExceptionMessages::NotASequenceTypeProperty(property_name));
-    return HeapVector<Member<T>>();
-  }
-
-  using VectorType = HeapVector<Member<T>>;
-  if (length > VectorType::MaxCapacity()) {
-    exception_state.ThrowRangeError("Array length exceeds supported limit.");
-    return VectorType();
-  }
-
-  VectorType result;
-  result.ReserveInitialCapacity(length);
-  v8::Local<v8::Object> object = v8::Local<v8::Object>::Cast(v8_value);
-  v8::TryCatch block(isolate);
-  for (uint32_t i = 0; i < length; ++i) {
-    v8::Local<v8::Value> element;
-    if (!V8Call(object->Get(isolate->GetCurrentContext(), i), element, block)) {
-      exception_state.RethrowV8Exception(block.Exception());
-      return VectorType();
-    }
-    if (V8TypeOf<T>::Type::hasInstance(element, isolate)) {
-      v8::Local<v8::Object> element_object =
-          v8::Local<v8::Object>::Cast(element);
-      result.UncheckedAppend(V8TypeOf<T>::Type::toImpl(element_object));
-    } else {
-      exception_state.ThrowTypeError("Invalid Array element type");
-      return VectorType();
-    }
-  }
-  return result;
-}
-
-// Converts a JavaScript value to an array as per the Web IDL specification:
-// http://www.w3.org/TR/2012/CR-WebIDL-20120419/#es-array
-template <typename VectorType,
-          typename ValueType = typename VectorType::ValueType>
-VectorType ToImplArray(v8::Local<v8::Value> value,
-                       int argument_index,
-                       v8::Isolate* isolate,
-                       ExceptionState& exception_state) {
-  typedef NativeValueTraits<ValueType> TraitsType;
-
-  uint32_t length = 0;
-  if (value->IsArray()) {
-    length = v8::Local<v8::Array>::Cast(value)->Length();
-  } else if (!ToV8Sequence(value, length, isolate, exception_state)) {
-    if (!exception_state.HadException())
-      exception_state.ThrowTypeError(
-          ExceptionMessages::NotAnArrayTypeArgumentOrValue(argument_index));
-    return VectorType();
-  }
-
-  if (length > VectorType::MaxCapacity()) {
-    exception_state.ThrowRangeError("Array length exceeds supported limit.");
-    return VectorType();
-  }
-
-  VectorType result;
-  result.ReserveInitialCapacity(length);
-  v8::Local<v8::Object> object = v8::Local<v8::Object>::Cast(value);
-  v8::TryCatch block(isolate);
-  for (uint32_t i = 0; i < length; ++i) {
-    v8::Local<v8::Value> element;
-    if (!V8Call(object->Get(isolate->GetCurrentContext(), i), element, block)) {
-      exception_state.RethrowV8Exception(block.Exception());
-      return VectorType();
-    }
-    result.UncheckedAppend(
-        TraitsType::NativeValue(isolate, element, exception_state));
-    if (exception_state.HadException())
-      return VectorType();
-  }
-  return result;
-}
-
-template <typename VectorType>
-VectorType ToImplArray(const Vector<ScriptValue>& value,
-                       v8::Isolate* isolate,
-                       ExceptionState& exception_state) {
-  using ValueType = typename VectorType::ValueType;
-  using TraitsType = NativeValueTraits<ValueType>;
-
-  if (value.size() > VectorType::MaxCapacity()) {
-    exception_state.ThrowRangeError("Array length exceeds supported limit.");
-    return VectorType();
-  }
-
-  VectorType result;
-  result.ReserveInitialCapacity(value.size());
-  for (unsigned i = 0; i < value.size(); ++i) {
-    result.UncheckedAppend(
-        TraitsType::NativeValue(isolate, value[i].V8Value(), exception_state));
-    if (exception_state.HadException())
-      return VectorType();
-  }
-  return result;
-}
-
 template <typename VectorType>
 VectorType ToImplArguments(const v8::FunctionCallbackInfo<v8::Value>& info,
                            int start_index,
                            ExceptionState& exception_state) {
   using ValueType = typename VectorType::ValueType;
   using TraitsType = NativeValueTraits<ValueType>;
 
   int length = info.Length();
   VectorType result;
   if (start_index < length) {
@@ skipping 10 matching lines @@
     }
   }
   return result;
 }
 
 // Gets an iterator from an Object.
 CORE_EXPORT v8::Local<v8::Object> GetEsIterator(v8::Isolate*,
                                                 v8::Local<v8::Object>,
                                                 ExceptionState&);
 
-// Validates that the passed object is a sequence type per WebIDL spec
-// http://www.w3.org/TR/2012/CR-WebIDL-20120419/#es-sequence
-inline bool ToV8Sequence(v8::Local<v8::Value> value,
-                         uint32_t& length,
-                         v8::Isolate* isolate,
-                         ExceptionState& exception_state) {
-  // Attempt converting to a sequence if the value is not already an array but
-  // is any kind of object except for a native Date object or a native RegExp
-  // object.
-  ASSERT(!value->IsArray());
-  // FIXME: Do we really need to special case Date and RegExp object?
-  // https://www.w3.org/Bugs/Public/show_bug.cgi?id=22806
-  if (!value->IsObject() || value->IsDate() || value->IsRegExp()) {
-    // The caller is responsible for reporting a TypeError.
-    return false;
-  }
-
-  v8::Local<v8::Object> object = v8::Local<v8::Object>::Cast(value);
-  v8::Local<v8::String> length_symbol = V8AtomicString(isolate, "length");
-
-  // FIXME: The specification states that the length property should be used as
-  // fallback, if value is not a platform object that supports indexed
-  // properties. If it supports indexed properties, length should actually be
-  // one greater than value's maximum indexed property index.
-  v8::TryCatch block(isolate);
-  v8::Local<v8::Value> length_value;
-  if (!V8Call(object->Get(isolate->GetCurrentContext(), length_symbol),
-              length_value, block)) {
-    exception_state.RethrowV8Exception(block.Exception());
-    return false;
-  }
-
-  if (length_value->IsUndefined() || length_value->IsNull()) {
-    // The caller is responsible for reporting a TypeError.
-    return false;
-  }
-
-  uint32_t sequence_length;
-  if (!V8Call(length_value->Uint32Value(isolate->GetCurrentContext()),
-              sequence_length, block)) {
-    exception_state.RethrowV8Exception(block.Exception());
-    return false;
-  }
-
-  length = sequence_length;
-  return true;
-}
+// Validates that the passed object is a sequence type per the WebIDL spec: it
+// has a callable @iterator.
+// https://heycam.github.io/webidl/#es-sequence
+CORE_EXPORT bool IsV8Sequence(v8::Local<v8::Value>,

[Yuki, 2017/04/11 07:17:11]

nit: If possible, could you make v8::Isolate* the first argument?

We'd like to follow V8's style as much as possible.  V8's style is to put
v8::Isolate* or v8::Context first.

+                              v8::Isolate*,
+                              ExceptionState&);
 
 // TODO(rakuco): remove the specializations below (and consequently the
 // non-IDLBase version of NativeValueTraitsBase) once we manage to convert all
 // uses of NativeValueTraits to types that derive from IDLBase or for generated
 // IDL interfaces/dictionaries/unions.
 template <>
 struct NativeValueTraits<String> {
   static inline String NativeValue(v8::Isolate* isolate,
                                    v8::Local<v8::Value> value,
                                    ExceptionState& exception_state) {
     V8StringResource<> string_value(value);
     if (!string_value.Prepare(exception_state))
       return String();
     return string_value;
   }
 };
 
 template <>
-struct NativeValueTraits<AtomicString> {
-  static inline AtomicString NativeValue(v8::Isolate* isolate,
-                                         v8::Local<v8::Value> value,
-                                         ExceptionState& exception_state) {
-    V8StringResource<> string_value(value);
-    if (!string_value.Prepare(exception_state))
-      return AtomicString();
-    return string_value;
-  }
-};
-
-template <>
-struct NativeValueTraits<int> {
-  static inline int NativeValue(v8::Isolate* isolate,
-                                v8::Local<v8::Value> value,
-                                ExceptionState& exception_state) {
-    return ToInt32(isolate, value, kNormalConversion, exception_state);
-  }
-};
-
-template <>
-struct NativeValueTraits<unsigned> {
-  static inline unsigned NativeValue(v8::Isolate* isolate,
-                                     v8::Local<v8::Value> value,
-                                     ExceptionState& exception_state) {
-    return ToUInt32(isolate, value, kNormalConversion, exception_state);
-  }
-};
-
-template <>
-struct NativeValueTraits<float> {
-  static inline float NativeValue(v8::Isolate* isolate,
-                                  v8::Local<v8::Value> value,
-                                  ExceptionState& exception_state) {
-    return ToFloat(isolate, value, exception_state);
-  }
-};
-
-template <>
-struct NativeValueTraits<double> {
-  static inline double NativeValue(v8::Isolate* isolate,
-                                   v8::Local<v8::Value> value,
-                                   ExceptionState& exception_state) {
-    return ToDouble(isolate, value, exception_state);
-  }
-};
-
-template <>
-struct NativeValueTraits<v8::Local<v8::Value>> {
+struct NativeValueTraits<v8::Local<v8::Value>>
+    : public NativeValueTraitsBase<v8::Local<v8::Value>> {
   static inline v8::Local<v8::Value> NativeValue(
       v8::Isolate* isolate,
       v8::Local<v8::Value> value,
       ExceptionState& exception_state) {
     return value;
   }
 };
 
-template <>
-struct NativeValueTraits<ScriptValue> {
-  static inline ScriptValue NativeValue(v8::Isolate* isolate,
-                                        v8::Local<v8::Value> value,
-                                        ExceptionState& exception_state) {
-    return ScriptValue(ScriptState::Current(isolate), value);
-  }
-};
-
-template <typename T>
-struct NativeValueTraits<Vector<T>> {
-  static inline Vector<T> NativeValue(v8::Isolate* isolate,
-                                      v8::Local<v8::Value> value,
-                                      ExceptionState& exception_state) {
-    return ToImplArray<Vector<T>>(value, 0, isolate, exception_state);
-  }
-};
-
 CORE_EXPORT v8::Isolate* ToIsolate(ExecutionContext*);
 CORE_EXPORT v8::Isolate* ToIsolate(LocalFrame*);
 
 CORE_EXPORT DOMWindow* ToDOMWindow(v8::Isolate*, v8::Local<v8::Value>);
 LocalDOMWindow* ToLocalDOMWindow(v8::Local<v8::Context>);
 LocalDOMWindow* EnteredDOMWindow(v8::Isolate*);
 CORE_EXPORT LocalDOMWindow* CurrentDOMWindow(v8::Isolate*);
 CORE_EXPORT ExecutionContext* ToExecutionContext(v8::Local<v8::Context>);
 CORE_EXPORT void RegisterToExecutionContextForModules(ExecutionContext* (
     *to_execution_context_for_modules)(v8::Local<v8::Context>));
@@ skipping 24 matching lines @@
 CORE_EXPORT LocalFrame* ToLocalFrameIfNotDetached(v8::Local<v8::Context>);
 
 // If 'storage' is non-null, it must be large enough to copy all bytes in the
 // array buffer view into it.  Use allocateFlexibleArrayBufferStorage(v8Value)
 // to allocate it using alloca() in the callers stack frame.
 CORE_EXPORT void ToFlexibleArrayBufferView(v8::Isolate*,
                                            v8::Local<v8::Value>,
                                            FlexibleArrayBufferView&,
                                            void* storage = nullptr);
 
-// Converts a V8 value to an array (an IDL sequence) as per the WebIDL
-// specification: http://heycam.github.io/webidl/#es-sequence
-template <typename VectorType>
-VectorType ToImplSequence(v8::Isolate* isolate,
-                          v8::Local<v8::Value> value,
-                          ExceptionState& exception_state) {
-  using ValueType = typename VectorType::ValueType;
-
-  if (!value->IsObject() || value->IsRegExp()) {
-    exception_state.ThrowTypeError(
-        "The provided value cannot be converted to a sequence.");
-    return VectorType();
-  }
-
-  v8::TryCatch block(isolate);
-  v8::Local<v8::Object> iterator =
-      GetEsIterator(isolate, value.As<v8::Object>(), exception_state);
-  if (exception_state.HadException())
-    return VectorType();
-
-  v8::Local<v8::String> next_key = V8String(isolate, "next");
-  v8::Local<v8::String> value_key = V8String(isolate, "value");
-  v8::Local<v8::String> done_key = V8String(isolate, "done");
-  v8::Local<v8::Context> context = isolate->GetCurrentContext();
-  VectorType result;
-  while (true) {
-    v8::Local<v8::Value> next;
-    if (!iterator->Get(context, next_key).ToLocal(&next)) {
-      exception_state.RethrowV8Exception(block.Exception());
-      return VectorType();
-    }
-    // TODO(bashi): Support callable objects.
-    if (!next->IsObject() || !next.As<v8::Object>()->IsFunction()) {
-      exception_state.ThrowTypeError("Iterator.next should be callable.");
-      return VectorType();
-    }
-    v8::Local<v8::Value> next_result;
-    if (!V8ScriptRunner::CallFunction(next.As<v8::Function>(),
-                                      ToExecutionContext(context), iterator, 0,
-                                      nullptr, isolate)
-             .ToLocal(&next_result)) {
-      exception_state.RethrowV8Exception(block.Exception());
-      return VectorType();
-    }
-    if (!next_result->IsObject()) {
-      exception_state.ThrowTypeError(
-          "Iterator.next() did not return an object.");
-      return VectorType();
-    }
-    v8::Local<v8::Object> result_object = next_result.As<v8::Object>();
-    v8::Local<v8::Value> element;
-    v8::Local<v8::Value> done;
-    if (!result_object->Get(context, value_key).ToLocal(&element) ||
-        !result_object->Get(context, done_key).ToLocal(&done)) {
-      exception_state.RethrowV8Exception(block.Exception());
-      return VectorType();
-    }
-    v8::Local<v8::Boolean> done_boolean;
-    if (!done->ToBoolean(context).ToLocal(&done_boolean)) {
-      exception_state.RethrowV8Exception(block.Exception());
-      return VectorType();
-    }
-    if (done_boolean->Value())
-      break;
-    result.push_back(NativeValueTraits<ValueType>::NativeValue(
-        isolate, element, exception_state));
-  }
-  return result;
-}
-
 // If the current context causes out of memory, JavaScript setting
 // is disabled and it returns true.
 bool HandleOutOfMemory();
 
 inline bool IsUndefinedOrNull(v8::Local<v8::Value> value) {
   return value.IsEmpty() || value->IsNull() || value->IsUndefined();
 }
 v8::Local<v8::Function> GetBoundFunction(v8::Local<v8::Function>);
 
 // FIXME: This will be soon embedded in the generated code.
@@ skipping 49 matching lines @@
 // If the argument isn't an object, this will crash.
 CORE_EXPORT v8::Local<v8::Value> FreezeV8Object(v8::Local<v8::Value>,
                                                 v8::Isolate*);
 
 CORE_EXPORT v8::Local<v8::Value> FromJSONString(v8::Isolate*,
                                                 const String& stringified_json,
                                                 ExceptionState&);
 }  // namespace blink
 
 #endif  // V8Binding_h