小前端读源码 - React16.7.0(五)

function completeUnitOfWork(workInProgress) {
  // Attempt to complete the current unit of work, then move to the
  // next sibling. If there are no more siblings, return to the
  // parent fiber.
  while (true) {
    // The current, flushed, state of this fiber is the alternate.
    // Ideally nothing should rely on this, but relying on it here
    // means that we don't need an additional field on the work in
    // progress.
    var current$$1 = workInProgress.alternate;
    {
      setCurrentFiber(workInProgress);
    }

    var returnFiber = workInProgress.return;
    var siblingFiber = workInProgress.sibling;

    if ((workInProgress.effectTag & Incomplete) === NoEffect) {
      if (true && replayFailedUnitOfWorkWithInvokeGuardedCallback) {
        // Don't replay if it fails during completion phase.
        mayReplayFailedUnitOfWork = false;
      }
      // This fiber completed.
      // Remember we're completing this unit so we can find a boundary if it fails.
      nextUnitOfWork = workInProgress;
      if (enableProfilerTimer) {
        if (workInProgress.mode & ProfileMode) {
          startProfilerTimer(workInProgress);
        }
        nextUnitOfWork = completeWork(current$$1, workInProgress, nextRenderExpirationTime);
        if (workInProgress.mode & ProfileMode) {
          // Update render duration assuming we didn't error.
          stopProfilerTimerIfRunningAndRecordDelta(workInProgress, false);
        }
      } else {
        nextUnitOfWork = completeWork(current$$1, workInProgress, nextRenderExpirationTime);
      }
      if (true && replayFailedUnitOfWorkWithInvokeGuardedCallback) {
        // We're out of completion phase so replaying is fine now.
        mayReplayFailedUnitOfWork = true;
      }
      stopWorkTimer(workInProgress);
      resetChildExpirationTime(workInProgress, nextRenderExpirationTime);
      {
        resetCurrentFiber();
      }

      if (nextUnitOfWork !== null) {
        // Completing this fiber spawned new work. Work on that next.
        return nextUnitOfWork;
      }

      if (returnFiber !== null &&
      // Do not append effects to parents if a sibling failed to complete
      (returnFiber.effectTag & Incomplete) === NoEffect) {
        // Append all the effects of the subtree and this fiber onto the effect
        // list of the parent. The completion order of the children affects the
        // side-effect order.
        if (returnFiber.firstEffect === null) {
          returnFiber.firstEffect = workInProgress.firstEffect;
        }
        if (workInProgress.lastEffect !== null) {
          if (returnFiber.lastEffect !== null) {
            returnFiber.lastEffect.nextEffect = workInProgress.firstEffect;
          }
          returnFiber.lastEffect = workInProgress.lastEffect;
        }

        // If this fiber had side-effects, we append it AFTER the children's
        // side-effects. We can perform certain side-effects earlier if
        // needed, by doing multiple passes over the effect list. We don't want
        // to schedule our own side-effect on our own list because if end up
        // reusing children we'll schedule this effect onto itself since we're
        // at the end.
        var effectTag = workInProgress.effectTag;
        // Skip both NoWork and PerformedWork tags when creating the effect list.
        // PerformedWork effect is read by React DevTools but shouldn't be committed.
        if (effectTag > PerformedWork) {
          if (returnFiber.lastEffect !== null) {
            returnFiber.lastEffect.nextEffect = workInProgress;
          } else {
            returnFiber.firstEffect = workInProgress;
          }
          returnFiber.lastEffect = workInProgress;
        }
      }

      if (true && ReactFiberInstrumentation_1.debugTool) {
        ReactFiberInstrumentation_1.debugTool.onCompleteWork(workInProgress);
      }

      if (siblingFiber !== null) {
        // If there is more work to do in this returnFiber, do that next.
        return siblingFiber;
      } else if (returnFiber !== null) {
        // If there's no more work in this returnFiber. Complete the returnFiber.
        workInProgress = returnFiber;
        continue;
      } else {
        // We've reached the root.
        return null;
      }
    } else {
      if (enableProfilerTimer && workInProgress.mode & ProfileMode) {
        // Record the render duration for the fiber that errored.
        stopProfilerTimerIfRunningAndRecordDelta(workInProgress, false);

        // Include the time spent working on failed children before continuing.
        var actualDuration = workInProgress.actualDuration;
        var child = workInProgress.child;
        while (child !== null) {
          actualDuration += child.actualDuration;
          child = child.sibling;
        }
        workInProgress.actualDuration = actualDuration;
      }

      // This fiber did not complete because something threw. Pop values off
      // the stack without entering the complete phase. If this is a boundary,
      // capture values if possible.
      var next = unwindWork(workInProgress, nextRenderExpirationTime);
      // Because this fiber did not complete, don't reset its expiration time.
      if (workInProgress.effectTag & DidCapture) {
        // Restarting an error boundary
        stopFailedWorkTimer(workInProgress);
      } else {
        stopWorkTimer(workInProgress);
      }

      {
        resetCurrentFiber();
      }

      if (next !== null) {
        stopWorkTimer(workInProgress);
        if (true && ReactFiberInstrumentation_1.debugTool) {
          ReactFiberInstrumentation_1.debugTool.onCompleteWork(workInProgress);
        }

        // If completing this work spawned new work, do that next. We'll come
        // back here again.
        // Since we're restarting, remove anything that is not a host effect
        // from the effect tag.
        next.effectTag &= HostEffectMask;
        return next;
      }

      if (returnFiber !== null) {
        // Mark the parent fiber as incomplete and clear its effect list.
        returnFiber.firstEffect = returnFiber.lastEffect = null;
        returnFiber.effectTag |= Incomplete;
      }

      if (true && ReactFiberInstrumentation_1.debugTool) {
        ReactFiberInstrumentation_1.debugTool.onCompleteWork(workInProgress);
      }

      if (siblingFiber !== null) {
        // If there is more work to do in this returnFiber, do that next.
        return siblingFiber;
      } else if (returnFiber !== null) {
        // If there's no more work in this returnFiber. Complete the returnFiber.
        workInProgress = returnFiber;
        continue;
      } else {
        return null;
      }
    }
  }

  // Without this explicit null return Flow complains of invalid return type
  // TODO Remove the above while(true) loop
  // eslint-disable-next-line no-unreachable
  return null;
}

function completeWork(current, workInProgress, renderExpirationTime) {
  var newProps = workInProgress.pendingProps;

  switch (workInProgress.tag) {
    case IndeterminateComponent:
      break;
    case LazyComponent:
      break;
    case SimpleMemoComponent:
    case FunctionComponent:
      break;
    case ClassComponent:
      {
        var Component = workInProgress.type;
        if (isContextProvider(Component)) {
          popContext(workInProgress);
        }
        break;
      }
    case HostRoot:
      {
        popHostContainer(workInProgress);
        popTopLevelContextObject(workInProgress);
        var fiberRoot = workInProgress.stateNode;
        if (fiberRoot.pendingContext) {
          fiberRoot.context = fiberRoot.pendingContext;
          fiberRoot.pendingContext = null;
        }
        if (current === null || current.child === null) {
          // If we hydrated, pop so that we can delete any remaining children
          // that weren't hydrated.
          popHydrationState(workInProgress);
          // This resets the hacky state to fix isMounted before committing.
          // TODO: Delete this when we delete isMounted and findDOMNode.
          workInProgress.effectTag &= ~Placement;
        }
        updateHostContainer(workInProgress);
        break;
      }
    case HostComponent:
      {
        popHostContext(workInProgress);
        var rootContainerInstance = getRootHostContainer();
        var type = workInProgress.type;
        if (current !== null && workInProgress.stateNode != null) {
          updateHostComponent$1(current, workInProgress, type, newProps, rootContainerInstance);

          if (current.ref !== workInProgress.ref) {
            markRef$1(workInProgress);
          }
        } else {
          if (!newProps) {
            !(workInProgress.stateNode !== null) ? invariant(false, 'We must have new props for new mounts. This error is likely caused by a bug in React. Please file an issue.') : void 0;
            // This can happen when we abort work.
            break;
          }

          var 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.
          var wasHydrated = popHydrationState(workInProgress);
          if (wasHydrated) {
            // TODO: Move this and createInstance step into the beginPhase
            // to consolidate.
            if (prepareToHydrateHostInstance(workInProgress, rootContainerInstance, currentHostContext)) {
              // If changes to the hydrated node needs to be applied at the
              // commit-phase we mark this as such.
              markUpdate(workInProgress);
            }
          } else {
            var instance = createInstance(type, newProps, rootContainerInstance, currentHostContext, workInProgress);

            appendAllChildren(instance, workInProgress, false, false);

            // 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, currentHostContext)) {
              markUpdate(workInProgress);
            }
            workInProgress.stateNode = instance;
          }

          if (workInProgress.ref !== null) {
            // If there is a ref on a host node we need to schedule a callback
            markRef$1(workInProgress);
          }
        }
        break;
      }
    case HostText:
      {
        var newText = newProps;
        if (current && workInProgress.stateNode != null) {
          var 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.
          updateHostText$1(current, workInProgress, oldText, newText);
        } else {
          if (typeof newText !== 'string') {
            !(workInProgress.stateNode !== null) ? invariant(false, 'We must have new props for new mounts. This error is likely caused by a bug in React. Please file an issue.') : void 0;
            // This can happen when we abort work.
          }
          var _rootContainerInstance = getRootHostContainer();
          var _currentHostContext = getHostContext();
          var _wasHydrated = popHydrationState(workInProgress);
          if (_wasHydrated) {
            if (prepareToHydrateHostTextInstance(workInProgress)) {
              markUpdate(workInProgress);
            }
          } else {
            workInProgress.stateNode = createTextInstance(newText, _rootContainerInstance, _currentHostContext, workInProgress);
          }
        }
        break;
      }
    case ForwardRef:
      break;
    case SuspenseComponent:
      {
        var nextState = workInProgress.memoizedState;
        if ((workInProgress.effectTag & DidCapture) !== NoEffect) {
          // Something suspended. Re-render with the fallback children.
          workInProgress.expirationTime = renderExpirationTime;
          // Do not reset the effect list.
          return workInProgress;
        }

        var nextDidTimeout = nextState !== null;
        var prevDidTimeout = current !== null && current.memoizedState !== null;

        if (current !== null && !nextDidTimeout && prevDidTimeout) {
          // We just switched from the fallback to the normal children. Delete
          // the fallback.
          // TODO: Would it be better to store the fallback fragment on
          var currentFallbackChild = current.child.sibling;
          if (currentFallbackChild !== null) {
            // Deletions go at the beginning of the return fiber's effect list
            var first = workInProgress.firstEffect;
            if (first !== null) {
              workInProgress.firstEffect = currentFallbackChild;
              currentFallbackChild.nextEffect = first;
            } else {
              workInProgress.firstEffect = workInProgress.lastEffect = currentFallbackChild;
              currentFallbackChild.nextEffect = null;
            }
            currentFallbackChild.effectTag = Deletion;
          }
        }

        // The children either timed out after previously being visible, or
        // were restored after previously being hidden. Schedule an effect
        // to update their visiblity.
        if (
        //
        nextDidTimeout !== prevDidTimeout ||
        // Outside concurrent mode, the primary children commit in an
        // inconsistent state, even if they are hidden. So if they are hidden,
        // we need to schedule an effect to re-hide them, just in case.
        (workInProgress.effectTag & ConcurrentMode) === NoContext && nextDidTimeout) {
          workInProgress.effectTag |= Update;
        }
        break;
      }
    case Fragment:
      break;
    case Mode:
      break;
    case Profiler:
      break;
    case HostPortal:
      popHostContainer(workInProgress);
      updateHostContainer(workInProgress);
      break;
    case ContextProvider:
      // Pop provider fiber
      popProvider(workInProgress);
      break;
    case ContextConsumer:
      break;
    case MemoComponent:
      break;
    case IncompleteClassComponent:
      {
        // Same as class component case. I put it down here so that the tags are
        // sequential to ensure this switch is compiled to a jump table.
        var _Component = workInProgress.type;
        if (isContextProvider(_Component)) {
          popContext(workInProgress);
        }
        break;
      }
    default:
      invariant(false, 'Unknown unit of work tag. This error is likely caused by a bug in React. Please file an issue.');
  }

  return null;
}

function onComplete(root, finishedWork, expirationTime) {
  root.pendingCommitExpirationTime = expirationTime;
  root.finishedWork = finishedWork;
}

function completeRoot(root, finishedWork, expirationTime) {
  // Check if there's a batch that matches this expiration time.
  var firstBatch = root.firstBatch;
  if (firstBatch !== null && firstBatch._expirationTime >= expirationTime) {
    if (completedBatches === null) {
      completedBatches = [firstBatch];
    } else {
      completedBatches.push(firstBatch);
    }
    if (firstBatch._defer) {
      // This root is blocked from committing by a batch. Unschedule it until
      // we receive another update.
      root.finishedWork = finishedWork;
      root.expirationTime = NoWork;
      return;
    }
  }

  // Commit the root.
  root.finishedWork = null;

  // Check if this is a nested update (a sync update scheduled during the
  // commit phase).
  if (root === lastCommittedRootDuringThisBatch) {
    // If the next root is the same as the previous root, this is a nested
    // update. To prevent an infinite loop, increment the nested update count.
    nestedUpdateCount++;
  } else {
    // Reset whenever we switch roots.
    lastCommittedRootDuringThisBatch = root;
    nestedUpdateCount = 0;
  }
  commitRoot(root, finishedWork);
}