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/**
* Copyright 2013-present, Facebook, Inc.
* All rights reserved.
*
* This source code is licensed under the BSD-style license found in the
* LICENSE file in the root directory of this source tree. An additional grant
* of patent rights can be found in the PATENTS file in the same directory.
*
*
*/
'use strict';
var ReactTypeOfWork = require('./ReactTypeOfWork');
var IndeterminateComponent = ReactTypeOfWork.IndeterminateComponent,
ClassComponent = ReactTypeOfWork.ClassComponent,
HostContainer = ReactTypeOfWork.HostContainer,
HostComponent = ReactTypeOfWork.HostComponent,
CoroutineComponent = ReactTypeOfWork.CoroutineComponent,
YieldComponent = ReactTypeOfWork.YieldComponent;
var _require = require('./ReactPriorityLevel'),
NoWork = _require.NoWork;
// An Instance is shared between all versions of a component. We can easily
// break this out into a separate object to avoid copying so much to the
// alternate versions of the tree. We put this on a single object for now to
// minimize the number of objects created during the initial render.
// A Fiber is work on a Component that needs to be done or was done. There can
// be more than one per component.
// This is a constructor of a POJO instead of a constructor function for a few
// reasons:
// 1) Nobody should add any instance methods on this. Instance methods can be
// more difficult to predict when they get optimized and they are almost
// never inlined properly in static compilers.
// 2) Nobody should rely on `instanceof Fiber` for type testing. We should
// always know when it is a fiber.
// 3) We can easily go from a createFiber call to calling a constructor if that
// is faster. The opposite is not true.
// 4) We might want to experiment with using numeric keys since they are easier
// to optimize in a non-JIT environment.
// 5) It should be easy to port this to a C struct and keep a C implementation
// compatible.
var createFiber = function (tag, key) {
return {
// Instance
tag: tag,
key: key,
type: null,
stateNode: null,
// Fiber
'return': null,
child: null,
sibling: null,
ref: null,
pendingProps: null,
memoizedProps: null,
updateQueue: null,
memoizedState: null,
callbackList: null,
output: null,
nextEffect: null,
firstEffect: null,
lastEffect: null,
pendingWorkPriority: NoWork,
progressedPriority: NoWork,
progressedChild: null,
alternate: null
};
};
function shouldConstruct(Component) {
return !!(Component.prototype && Component.prototype.isReactComponent);
}
// This is used to create an alternate fiber to do work on.
// TODO: Rename to createWorkInProgressFiber or something like that.
exports.cloneFiber = function (fiber, priorityLevel) {
// We clone to get a work in progress. That means that this fiber is the
// current. To make it safe to reuse that fiber later on as work in progress
// we need to reset its work in progress flag now. We don't have an
// opportunity to do this earlier since we don't traverse the tree when
// the work in progress tree becomes the current tree.
// fiber.progressedPriority = NoWork;
// fiber.progressedChild = null;
// We use a double buffering pooling technique because we know that we'll only
// ever need at most two versions of a tree. We pool the "other" unused node
// that we're free to reuse. This is lazily created to avoid allocating extra
// objects for things that are never updated. It also allow us to reclaim the
// extra memory if needed.
var alt = fiber.alternate;
if (alt) {
// Whenever we clone, we do so to get a new work in progress.
// This ensures that we've reset these in the new tree.
alt.nextEffect = null;
alt.firstEffect = null;
alt.lastEffect = null;
} else {
// This should not have an alternate already
alt = createFiber(fiber.tag, fiber.key);
alt.type = fiber.type;
alt.progressedChild = fiber.progressedChild;
alt.progressedPriority = fiber.progressedPriority;
alt.alternate = fiber;
fiber.alternate = alt;
}
alt.stateNode = fiber.stateNode;
alt.child = fiber.child;
alt.sibling = fiber.sibling; // This should always be overridden. TODO: null
alt.ref = fiber.ref;
// pendingProps is here for symmetry but is unnecessary in practice for now.
// TODO: Pass in the new pendingProps as an argument maybe?
alt.pendingProps = fiber.pendingProps;
alt.updateQueue = fiber.updateQueue;
alt.callbackList = fiber.callbackList;
alt.pendingWorkPriority = priorityLevel;
alt.memoizedProps = fiber.memoizedProps;
alt.output = fiber.output;
return alt;
};
exports.createHostContainerFiber = function () {
var fiber = createFiber(HostContainer, null);
return fiber;
};
exports.createFiberFromElement = function (element, priorityLevel) {
// $FlowFixMe: ReactElement.key is currently defined as ?string but should be defined as null | string in Flow.
var fiber = createFiberFromElementType(element.type, element.key);
fiber.pendingProps = element.props;
fiber.pendingWorkPriority = priorityLevel;
return fiber;
};
function createFiberFromElementType(type, key) {
var fiber = void 0;
if (typeof type === 'function') {
fiber = shouldConstruct(type) ? createFiber(ClassComponent, key) : createFiber(IndeterminateComponent, key);
fiber.type = type;
} else if (typeof type === 'string') {
fiber = createFiber(HostComponent, key);
fiber.type = type;
} else if (typeof type === 'object' && type !== null) {
// Currently assumed to be a continuation and therefore is a fiber already.
fiber = type;
} else {
throw new Error('Unknown component type: ' + typeof type);
}
return fiber;
}
exports.createFiberFromElementType = createFiberFromElementType;
exports.createFiberFromCoroutine = function (coroutine, priorityLevel) {
var fiber = createFiber(CoroutineComponent, coroutine.key);
fiber.type = coroutine.handler;
fiber.pendingProps = coroutine;
fiber.pendingWorkPriority = priorityLevel;
return fiber;
};
exports.createFiberFromYield = function (yieldNode, priorityLevel) {
var fiber = createFiber(YieldComponent, yieldNode.key);
fiber.pendingProps = {};
return fiber;
};
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