react-native/Libraries/Renderer/src/renderers/shared/fiber/ReactFiberCompleteWork.js

A framework for building native apps using React

/**
 * 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.
 *
 * @providesModule ReactFiberCompleteWork
 * @flow
 */

'use strict';

import type { ReactCoroutine } from 'ReactCoroutine';
import type { Fiber } from 'ReactFiber';
import type { HostContext } from 'ReactFiberHostContext';
import type { FiberRoot } from 'ReactFiberRoot';
import type { HostConfig } from 'ReactFiberReconciler';

var { reconcileChildFibers } = require('ReactChildFiber');
var {
  popContextProvider,
} = require('ReactFiberContext');
var ReactTypeOfWork = require('ReactTypeOfWork');
var ReactTypeOfSideEffect = require('ReactTypeOfSideEffect');
var {
  IndeterminateComponent,
  FunctionalComponent,
  ClassComponent,
  HostRoot,
  HostComponent,
  HostText,
  HostPortal,
  CoroutineComponent,
  CoroutineHandlerPhase,
  YieldComponent,
  Fragment,
} = ReactTypeOfWork;
var {
  Ref,
  Update,
} = ReactTypeOfSideEffect;

if (__DEV__) {
  var ReactDebugCurrentFiber = require('ReactDebugCurrentFiber');
}

var invariant = require('fbjs/lib/invariant');

module.exports = function<T, P, I, TI, PI, C, CX, PL>(
  config : HostConfig<T, P, I, TI, PI, C, CX, PL>,
  hostContext : HostContext<C, CX>,
) {
  const {
    createInstance,
    createTextInstance,
    appendInitialChild,
    finalizeInitialChildren,
    prepareUpdate,
  } = config;

  const {
    getRootHostContainer,
    popHostContext,
    getHostContext,
    popHostContainer,
  } = hostContext;

  function markChildAsProgressed(current, workInProgress, priorityLevel) {
    // We now have clones. Let's store them as the currently progressed work.
    workInProgress.progressedChild = workInProgress.child;
    workInProgress.progressedPriority = priorityLevel;
    if (current !== null) {
      // We also store it on the current. When the alternate swaps in we can
      // continue from this point.
      current.progressedChild = workInProgress.progressedChild;
      current.progressedPriority = workInProgress.progressedPriority;
    }
  }

  function markUpdate(workInProgress : Fiber) {
    // Tag the fiber with an update effect. This turns a Placement into
    // an UpdateAndPlacement.
    workInProgress.effectTag |= Update;
  }

  function appendAllYields(yields : Array<mixed>, workInProgress : Fiber) {
    let node = workInProgress.stateNode;
    if (node) {
      node.return = workInProgress;
    }
    while (node !== null) {
      if (node.tag === HostComponent || node.tag === HostText ||
          node.tag === HostPortal) {
        invariant(
          false,
          'A coroutine cannot have host component children.'
        );
      } else if (node.tag === YieldComponent) {
        yields.push(node.type);
      } else if (node.child !== null) {
        node.child.return = node;
        node = node.child;
        continue;
      }
      while (node.sibling === null) {
        if (node.return === null || node.return === workInProgress) {
          return;
        }
        node = node.return;
      }
      node.sibling.return = node.return;
      node = node.sibling;
    }
  }

  function moveCoroutineToHandlerPhase(current : Fiber | null, workInProgress : Fiber) {
    var coroutine = (workInProgress.memoizedProps : ?ReactCoroutine);
    invariant(
      coroutine,
      'Should be resolved by now. This error is likely caused by a bug in ' +
      'React. Please file an issue.',
    );

    // First step of the coroutine has completed. Now we need to do the second.
    // TODO: It would be nice to have a multi stage coroutine represented by a
    // single component, or at least tail call optimize nested ones. Currently
    // that requires additional fields that we don't want to add to the fiber.
    // So this requires nested handlers.
    // Note: This doesn't mutate the alternate node. I don't think it needs to
    // since this stage is reset for every pass.
    workInProgress.tag = CoroutineHandlerPhase;

    // Build up the yields.
    // TODO: Compare this to a generator or opaque helpers like Children.
    var yields : Array<mixed> = [];
    appendAllYields(yields, workInProgress);
    var fn = coroutine.handler;
    var props = coroutine.props;
    var nextChildren = fn(props, yields);

    var currentFirstChild = current !== null ? current.child : null;
    // Inherit the priority of the returnFiber.
    const priority = workInProgress.pendingWorkPriority;
    workInProgress.child = reconcileChildFibers(
      workInProgress,
      currentFirstChild,
      nextChildren,
      priority
    );
    markChildAsProgressed(current, workInProgress, priority);
    return workInProgress.child;
  }

  function appendAllChildren(parent : I, workInProgress : Fiber) {
    // We only have the top Fiber that was created but we need recurse down its
    // children to find all the terminal nodes.
    let node = workInProgress.child;
    while (node !== null) {
      if (node.tag === HostComponent || node.tag === HostText) {
        appendInitialChild(parent, node.stateNode);
      } else if (node.tag === HostPortal) {
        // If we have a portal child, then we don't want to traverse
        // down its children. Instead, we'll get insertions from each child in
        // the portal directly.
      } else if (node.child !== null) {
        node = node.child;
        continue;
      }
      if (node === workInProgress) {
        return;
      }
      while (node.sibling === null) {
        if (node.return === null || node.return === workInProgress) {
          return;
        }
        node = node.return;
      }
      node = node.sibling;
    }
  }

  function completeWork(current : Fiber | null, workInProgress : Fiber) : Fiber | null {
    if (__DEV__) {
      ReactDebugCurrentFiber.current = workInProgress;
    }

    switch (workInProgress.tag) {
      case FunctionalComponent:
        return null;
      case ClassComponent: {
        // We are leaving this subtree, so pop context if any.
        popContextProvider(workInProgress);
        return null;
      }
      case HostRoot: {
        // TODO: Pop the host container after #8607 lands.
        const fiberRoot = (workInProgress.stateNode : FiberRoot);
        if (fiberRoot.pendingContext) {
          fiberRoot.context = fiberRoot.pendingContext;
          fiberRoot.pendingContext = null;
        }
        return null;
      }
      case HostComponent: {
        popHostContext(workInProgress);
        const rootContainerInstance = getRootHostContainer();
        const type = workInProgress.type;
        const newProps = workInProgress.memoizedProps;
        if (current !== null && workInProgress.stateNode != null) {
          // If we have an alternate, that means this is an update and we need to
          // schedule a side-effect to do the updates.
          const oldProps = current.memoizedProps;
          // If we get updated because one of our children updated, we don't
          // have newProps so we'll have to reuse them.
          // TODO: Split the update API as separate for the props vs. children.
          // Even better would be if children weren't special cased at all tho.
          const instance : I = workInProgress.stateNode;
          const currentHostContext = getHostContext();
          const updatePayload = prepareUpdate(
            instance,
            type,
            oldProps,
            newProps,
            rootContainerInstance,
            currentHostContext
          );

          // TODO: Type this specific to this type of component.
          workInProgress.updateQueue = (updatePayload : any);
          // If the update payload indicates that there is a change or if there
          // is a new ref we mark this as an update.
          if (updatePayload || current.ref !== workInProgress.ref) {
            markUpdate(workInProgress);
          }
        } else {
          if (!newProps) {
            invariant(
              workInProgress.stateNode !== null,
              'We must have new props for new mounts. This error is likely ' +
              'caused by a bug in React. Please file an issue.'
            );
            // This can happen when we abort work.
            return null;
          }

          const currentHostContext = getHostContext();
          // TODO: Move createInstance to beginWork and keep it on a context
          // "stack" as the parent. Then append children as we go in beginWork
          // or completeWork depending on we want to add then top->down or
          // bottom->up. Top->down is faster in IE11.
          const instance = createInstance(
            type,
            newProps,
            rootContainerInstance,
            currentHostContext,
            workInProgress
          );

          appendAllChildren(instance, workInProgress);

          // Certain renderers require commit-time effects for initial mount.
          // (eg DOM renderer supports auto-focus for certain elements).
          // Make sure such renderers get scheduled for later work.
          if (finalizeInitialChildren(instance, type, newProps, rootContainerInstance)) {
            markUpdate(workInProgress);
          }

          workInProgress.stateNode = instance;
          if (workInProgress.ref !== null) {
            // If there is a ref on a host node we need to schedule a callback
            workInProgress.effectTag |= Ref;
          }
        }
        return null;
      }
      case HostText: {
        let newText = workInProgress.memoizedProps;
        if (current && workInProgress.stateNode != null) {
          const oldText = current.memoizedProps;
          // If we have an alternate, that means this is an update and we need
          // to schedule a side-effect to do the updates.
          if (oldText !== newText) {
            markUpdate(workInProgress);
          }
        } else {
          if (typeof newText !== 'string') {
            invariant(
              workInProgress.stateNode !== null,
              'We must have new props for new mounts. This error is likely ' +
              'caused by a bug in React. Please file an issue.'
            );
            // This can happen when we abort work.
            return null;
          }
          const rootContainerInstance = getRootHostContainer();
          const currentHostContext = getHostContext();
          const textInstance = createTextInstance(newText, rootContainerInstance, currentHostContext, workInProgress);
          workInProgress.stateNode = textInstance;
        }
        return null;
      }
      case CoroutineComponent:
        return moveCoroutineToHandlerPhase(current, workInProgress);
      case CoroutineHandlerPhase:
        // Reset the tag to now be a first phase coroutine.
        workInProgress.tag = CoroutineComponent;
        return null;
      case YieldComponent:
        // Does nothing.
        return null;
      case Fragment:
        return null;
      case HostPortal:
        // TODO: Only mark this as an update if we have any pending callbacks.
        markUpdate(workInProgress);
        popHostContainer(workInProgress);
        return null;

      // Error cases
      case IndeterminateComponent:
        invariant(
          false,
          'An indeterminate component should have become determinate before ' +
          'completing. This error is likely caused by a bug in React. Please ' +
          'file an issue.'
        );
        // eslint-disable-next-line no-fallthrough
      default:
        invariant(
          false,
          'Unknown unit of work tag. This error is likely caused by a bug in ' +
          'React. Please file an issue.'
        );
    }
  }

  return {
    completeWork,
  };

};