Files
react-native/ReactCommon/fabric/core/state/StateData.h
T
Joshua Gross 309de462bd Support setting partial state from Android, and filling in data with previous State constructor
Summary:
iOS and other platforms have direct access to C++ StateT structs, whereas Java only has access to a Java map equivalent - state updates from Java can't update complex types, or must incur significant cost to reconstruct large objects from their folly::dynamic representation (not to mention the complexity of implementing the Java-to-C++ struct converters). Thus it's hard for Java to update StateT's with complex types on the C++ side.

This diff makes a minor change to Android's updateState which uses both the folly::dynamic data from Java as well as the previous State, so each StateT can have fields that are read-only from the Java perspective.

Motivation: For AndroidTextInput we need to set params from Java, without being able to send all of the State params from Java.

In this diff, we introduce a new State constructor that takes the previous State value and a folly::dynamic. It is up to each State implementation how the additional parameter will be used.

We migrate every existing component except for AndroidTextInput in this diff.

Changelog: [Internal]

Reviewed By: mdvacca

Differential Revision: D18672365

fbshipit-source-id: 4469e0a3c7658c204089c6fed39394979883f124
2019-11-27 12:55:47 -08:00

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683 B
C++

/*
* Copyright (c) Facebook, Inc. and its affiliates.
*
* This source code is licensed under the MIT license found in the
* LICENSE file in the root directory of this source tree.
*/
#pragma once
#include <memory>
#ifdef ANDROID
#include <folly/dynamic.h>
#endif
namespace facebook {
namespace react {
/*
* Dummy type that is used as a placeholder for state data for nodes that
* don't have a state.
*/
struct StateData final {
using Shared = std::shared_ptr<void>;
#ifdef ANDROID
StateData() = default;
StateData(StateData const &previousState, folly::dynamic data){};
folly::dynamic getDynamic() const;
#endif
};
} // namespace react
} // namespace facebook