react-native/ReactCommon/bridge/Value.cpp

// Copyright 2004-present Facebook. All Rights Reserved.

#include "Value.h"

#include "JSCHelpers.h"

namespace facebook {
namespace react {

Value::Value(JSContextRef context, JSValueRef value) :
  m_context(context),
  m_value(value)
{
}

Value::Value(Value&& other) :
  m_context(other.m_context),
  m_value(other.m_value)
{
  other.m_value = nullptr;
}

JSContextRef Value::context() const {
  return m_context;
}

std::string Value::toJSONString(unsigned indent) const {
  JSValueRef exn;
  auto stringToAdopt = JSValueCreateJSONString(m_context, m_value, indent, &exn);
  if (stringToAdopt == nullptr) {
    std::string exceptionText = Value(m_context, exn).toString().str();
    throwJSExecutionException("Exception creating JSON string: %s", exceptionText.c_str());
  }
  return String::adopt(stringToAdopt).str();
}

/* static */
Value Value::fromJSON(JSContextRef ctx, const String& json) {
  auto result = JSValueMakeFromJSONString(ctx, json);
  if (!result) {
    throwJSExecutionException("Failed to create String from JSON");
  }
  return Value(ctx, result);
}

Object Value::asObject() {
  JSValueRef exn;
  JSObjectRef jsObj = JSValueToObject(context(), m_value, &exn);
  if (!jsObj) {
    std::string exceptionText = Value(m_context, exn).toString().str();
    throwJSExecutionException("Failed to convert to object: %s", exceptionText.c_str());
  }
  Object ret = Object(context(), jsObj);
  m_value = nullptr;
  return ret;
}

Object::operator Value() const {
  return Value(m_context, m_obj);
}

Value Object::callAsFunction(int nArgs, JSValueRef args[]) {
  JSValueRef exn;
  JSValueRef result = JSObjectCallAsFunction(m_context, m_obj, NULL, nArgs, args, &exn);
  if (!result) {
    std::string exceptionText = Value(m_context, exn).toString().str();
    throwJSExecutionException("Exception calling JS function: %s", exceptionText.c_str());
  }
  return Value(m_context, result);
}

Value Object::getProperty(const String& propName) const {
  JSValueRef exn;
  JSValueRef property = JSObjectGetProperty(m_context, m_obj, propName, &exn);
  if (!property) {
    std::string exceptionText = Value(m_context, exn).toString().str();
    throwJSExecutionException("Failed to get property: %s", exceptionText.c_str());
  }
  return Value(m_context, property);
}

Value Object::getPropertyAtIndex(unsigned index) const {
  JSValueRef exn;
  JSValueRef property = JSObjectGetPropertyAtIndex(m_context, m_obj, index, &exn);
  if (!property) {
    std::string exceptionText = Value(m_context, exn).toString().str();
    throwJSExecutionException("Failed to get property at index %u: %s", index, exceptionText.c_str());
  }
  return Value(m_context, property);
}

Value Object::getProperty(const char *propName) const {
  return getProperty(String(propName));
}

void Object::setProperty(const String& propName, const Value& value) const {
  JSValueRef exn = NULL;
  JSObjectSetProperty(m_context, m_obj, propName, value, kJSPropertyAttributeNone, &exn);
  if (exn) {
    std::string exceptionText = Value(m_context, exn).toString().str();
    throwJSExecutionException("Failed to set property: %s", exceptionText.c_str());
  }
}

void Object::setProperty(const char *propName, const Value& value) const {
  setProperty(String(propName), value);
}

std::vector<std::string> Object::getPropertyNames() const {
  std::vector<std::string> names;
  auto namesRef = JSObjectCopyPropertyNames(m_context, m_obj);
  size_t count = JSPropertyNameArrayGetCount(namesRef);
  for (size_t i = 0; i < count; i++) {
    auto string = String::ref(JSPropertyNameArrayGetNameAtIndex(namesRef, i));
    names.emplace_back(string.str());
  }
  JSPropertyNameArrayRelease(namesRef);
  return names;
}

std::unordered_map<std::string, std::string> Object::toJSONMap() const {
  std::unordered_map<std::string, std::string> map;
  auto namesRef = JSObjectCopyPropertyNames(m_context, m_obj);
  size_t count = JSPropertyNameArrayGetCount(namesRef);
  for (size_t i = 0; i < count; i++) {
    auto key = String::ref(JSPropertyNameArrayGetNameAtIndex(namesRef, i));
    map.emplace(key.str(), getProperty(key).toJSONString());
  }
  JSPropertyNameArrayRelease(namesRef);
  return map;
}

/* static */
Object Object::create(JSContextRef ctx) {
  JSObjectRef newObj = JSObjectMake(
      ctx,
      NULL, // create instance of default object class
      NULL); // no private data
  return Object(ctx, newObj);
}

} }