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ReactFiberTreeReflection.js
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ReactFiberTreeReflection.js
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/**
* 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.
*
* @flow
*/
import type {Fiber} from './ReactFiber';
import invariant from 'shared/invariant';
import warningWithoutStack from 'shared/warningWithoutStack';
import {get as getInstance} from 'shared/ReactInstanceMap';
import ReactSharedInternals from 'shared/ReactSharedInternals';
import getComponentName from 'shared/getComponentName';
import {
ClassComponent,
HostComponent,
HostRoot,
HostPortal,
HostText,
} from 'shared/ReactWorkTags';
import {NoEffect, Placement} from 'shared/ReactSideEffectTags';
const ReactCurrentOwner = ReactSharedInternals.ReactCurrentOwner;
const MOUNTING = 1;
const MOUNTED = 2;
const UNMOUNTED = 3;
function isFiberMountedImpl(fiber: Fiber): number {
let node = fiber;
if (!fiber.alternate) {
// If there is no alternate, this might be a new tree that isn't inserted
// yet. If it is, then it will have a pending insertion effect on it.
if ((node.effectTag & Placement) !== NoEffect) {
return MOUNTING;
}
while (node.return) {
node = node.return;
if ((node.effectTag & Placement) !== NoEffect) {
return MOUNTING;
}
}
} else {
while (node.return) {
node = node.return;
}
}
if (node.tag === HostRoot) {
// TODO: Check if this was a nested HostRoot when used with
// renderContainerIntoSubtree.
return MOUNTED;
}
// If we didn't hit the root, that means that we're in an disconnected tree
// that has been unmounted.
return UNMOUNTED;
}
export function isFiberMounted(fiber: Fiber): boolean {
return isFiberMountedImpl(fiber) === MOUNTED;
}
export function isMounted(component: React$Component<any, any>): boolean {
if (__DEV__) {
const owner = (ReactCurrentOwner.current: any);
if (owner !== null && owner.tag === ClassComponent) {
const ownerFiber: Fiber = owner;
const instance = ownerFiber.stateNode;
warningWithoutStack(
instance._warnedAboutRefsInRender,
'%s is accessing isMounted inside its render() function. ' +
'render() should be a pure function of props and state. It should ' +
'never access something that requires stale data from the previous ' +
'render, such as refs. Move this logic to componentDidMount and ' +
'componentDidUpdate instead.',
getComponentName(ownerFiber.type) || 'A component',
);
instance._warnedAboutRefsInRender = true;
}
}
const fiber: ?Fiber = getInstance(component);
if (!fiber) {
return false;
}
return isFiberMountedImpl(fiber) === MOUNTED;
}
function assertIsMounted(fiber) {
invariant(
isFiberMountedImpl(fiber) === MOUNTED,
'Unable to find node on an unmounted component.',
);
}
export function findCurrentFiberUsingSlowPath(fiber: Fiber): Fiber | null {
let alternate = fiber.alternate;
if (!alternate) {
// If there is no alternate, then we only need to check if it is mounted.
const state = isFiberMountedImpl(fiber);
invariant(
state !== UNMOUNTED,
'Unable to find node on an unmounted component.',
);
if (state === MOUNTING) {
return null;
}
return fiber;
}
// If we have two possible branches, we'll walk backwards up to the root
// to see what path the root points to. On the way we may hit one of the
// special cases and we'll deal with them.
let a = fiber;
let b = alternate;
while (true) {
let parentA = a.return;
if (!parentA) {
// We're at the root.
break;
}
// If both copies of the parent fiber point to the same child (or if there
// is only a single parent fiber), we can assume that the child is current.
// This happens when we bailout on low priority: the bailed out fiber's
// child reuses the current child.
let parentB = parentA.alternate;
if (parentB === null || parentA.child === parentB.child) {
let child = parentA.child;
while (child) {
if (child === a) {
// We've determined that A is the current branch.
assertIsMounted(parentA);
return fiber;
}
if (child === b) {
// We've determined that B is the current branch.
assertIsMounted(parentA);
return alternate;
}
child = child.sibling;
}
// We should never have an alternate for any mounting node. So the only
// way this could possibly happen is if this was unmounted, if at all.
invariant(false, 'Unable to find node on an unmounted component.');
}
if (a.return !== b.return) {
// The return pointer of A and the return pointer of B point to different
// fibers. We assume that return pointers never criss-cross, so A must
// belong to the child set of A.return, and B must belong to the child
// set of B.return.
a = parentA;
b = parentB;
} else {
// The return pointers point to the same fiber. We'll have to use the
// default, slow path: scan the child sets of each parent alternate to see
// which child belongs to which set.
//
// Search parent A's child set
let didFindChild = false;
let child = parentA.child;
while (child) {
if (child === a) {
didFindChild = true;
a = parentA;
b = parentB;
break;
}
if (child === b) {
didFindChild = true;
b = parentA;
a = parentB;
break;
}
child = child.sibling;
}
if (!didFindChild) {
// Search parent B's child set
child = parentB.child;
while (child) {
if (child === a) {
didFindChild = true;
a = parentB;
b = parentA;
break;
}
if (child === b) {
didFindChild = true;
b = parentB;
a = parentA;
break;
}
child = child.sibling;
}
invariant(
didFindChild,
'Child was not found in either parent set. This indicates a bug ' +
'in React related to the return pointer. Please file an issue.',
);
}
}
invariant(
a.alternate === b,
"Return fibers should always be each others' alternates. " +
'This error is likely caused by a bug in React. Please file an issue.',
);
}
// If the root is not a host container, we're in a disconnected tree. I.e.
// unmounted.
invariant(
a.tag === HostRoot,
'Unable to find node on an unmounted component.',
);
if (a.stateNode.current === a) {
// We've determined that A is the current branch.
return fiber;
}
// Otherwise B has to be current branch.
return alternate;
}
export function findCurrentHostFiber(parent: Fiber): Fiber | null {
const currentParent = findCurrentFiberUsingSlowPath(parent);
if (!currentParent) {
return null;
}
// Next we'll drill down this component to find the first HostComponent/Text.
let node: Fiber = currentParent;
while (true) {
if (node.tag === HostComponent || node.tag === HostText) {
return node;
} else if (node.child) {
node.child.return = node;
node = node.child;
continue;
}
if (node === currentParent) {
return null;
}
while (!node.sibling) {
if (!node.return || node.return === currentParent) {
return null;
}
node = node.return;
}
node.sibling.return = node.return;
node = node.sibling;
}
// Flow needs the return null here, but ESLint complains about it.
// eslint-disable-next-line no-unreachable
return null;
}
export function findCurrentHostFiberWithNoPortals(parent: Fiber): Fiber | null {
const currentParent = findCurrentFiberUsingSlowPath(parent);
if (!currentParent) {
return null;
}
// Next we'll drill down this component to find the first HostComponent/Text.
let node: Fiber = currentParent;
while (true) {
if (node.tag === HostComponent || node.tag === HostText) {
return node;
} else if (node.child && node.tag !== HostPortal) {
node.child.return = node;
node = node.child;
continue;
}
if (node === currentParent) {
return null;
}
while (!node.sibling) {
if (!node.return || node.return === currentParent) {
return null;
}
node = node.return;
}
node.sibling.return = node.return;
node = node.sibling;
}
// Flow needs the return null here, but ESLint complains about it.
// eslint-disable-next-line no-unreachable
return null;
}