Valentin Shergin 67a79010ca Fabric: Simplified way to specialize ComponentName in ConcreteShadowNode class template
Summary:
@public
Previously, all ConcreteShadowNode subclasses had to override `getComponentName()` function to specialize a name of the component. And often it was all that those subclasses do. Now, it's a template argument; and many ShadowNode classes can be created as oneliners via *just* specializing  ConcreteShadowNode template.

Unfortunately, C++ does not allow to use `std::string`s or string literals as template arguments, but it allows to use pointers. Moreover, those pointers must point to some linked data, hence, those values must be declared in .cpp (not .h) files. For simplicity, we put those constants in Props classes, (but this is not a strong requirement).

Reviewed By: mdvacca

Differential Revision: D8942826

fbshipit-source-id: 4fd517e2485eb8f8c20a51df9b3496941856d8a5
2018-08-04 09:47:30 -07:00

48 lines
1.2 KiB
C++

/**
* Copyright (c) 2015-present, Facebook, Inc.
*
* 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>
#include <string>
#include <unordered_map>
#include <folly/dynamic.h>
namespace facebook {
namespace react {
/*
* `Tag` and `InstanceHandle` are used to address React Native components.
*/
using Tag = int32_t;
using InstanceHandle = struct InstanceHandleDummyStruct {} *;
/*
* `RawProps` represents untyped map with props comes from JavaScript side.
*/
// TODO(T26954420): Use iterator as underlying type for RawProps.
using RawProps = std::unordered_map<std::string, folly::dynamic>;
using SharedRawProps = std::shared_ptr<const RawProps>;
/*
* Universal component handle which allows to refer to `ComponentDescriptor`s
* in maps efficiently.
* Practically, it's something that concrete ShadowNode and concrete
* ComponentDescriptor have in common.
*/
using ComponentHandle = int64_t;
/*
* String identifier for components used for addressing them from
* JavaScript side.
*/
using ComponentName = std::string;
} // namespace react
} // namespace facebook