| 1 | /** |
| 2 | * Copyright (c) Meta Platforms, Inc. and affiliates. |
| 3 | * |
| 4 | * This source code is licensed under the MIT license found in the |
| 5 | * LICENSE file in the root directory of this source tree. |
| 6 | * |
| 7 | * @flow |
| 8 | */ |
| 9 | |
| 10 | import type {Fiber} from './ReactInternalTypes'; |
| 11 | import type {StackCursor} from './ReactFiberStack'; |
| 12 | import type { |
| 13 | Container, |
| 14 | HostContext, |
| 15 | TransitionStatus, |
| 16 | } from './ReactFiberConfig'; |
| 17 | import type {Hook} from './ReactFiberHooks'; |
| 18 | |
| 19 | import { |
| 20 | getChildHostContext, |
| 21 | getRootHostContext, |
| 22 | HostTransitionContext, |
| 23 | NotPendingTransition, |
| 24 | isPrimaryRenderer, |
| 25 | } from './ReactFiberConfig'; |
| 26 | import {createCursor, push, pop} from './ReactFiberStack'; |
| 27 | |
| 28 | const contextStackCursor: StackCursor<HostContext | null> = createCursor(null); |
| 29 | const contextFiberStackCursor: StackCursor<Fiber | null> = createCursor(null); |
| 30 | const rootInstanceStackCursor: StackCursor<Container | null> = |
| 31 | createCursor(null); |
| 32 | |
| 33 | // Represents the nearest host transition provider (in React DOM, a <form />) |
| 34 | // NOTE: Since forms cannot be nested, and this feature is only implemented by |
| 35 | // React DOM, we don't technically need this to be a stack. It could be a single |
| 36 | // module variable instead. |
| 37 | const hostTransitionProviderCursor: StackCursor<Fiber | null> = |
| 38 | createCursor(null); |
| 39 | |
| 40 | function requiredContext<Value>(c: Value | null): Value { |
| 41 | if (__DEV__) { |
| 42 | if (c === null) { |
| 43 | console.error( |
| 44 | 'Expected host context to exist. This error is likely caused by a bug ' + |
| 45 | 'in React. Please file an issue.', |
| 46 | ); |
| 47 | } |
| 48 | } |
| 49 | return c as any; |
| 50 | } |
| 51 | |
| 52 | function getCurrentRootHostContainer(): null | Container { |
| 53 | return rootInstanceStackCursor.current; |
| 54 | } |
| 55 | |
| 56 | function getRootHostContainer(): Container { |
| 57 | const rootInstance = requiredContext(rootInstanceStackCursor.current); |
| 58 | return rootInstance; |
| 59 | } |
| 60 | |
| 61 | export function getHostTransitionProvider(): Fiber | null { |
| 62 | return hostTransitionProviderCursor.current; |
| 63 | } |
| 64 | |
| 65 | function pushHostContainer(fiber: Fiber, nextRootInstance: Container): void { |
| 66 | // Push current root instance onto the stack; |
| 67 | // This allows us to reset root when portals are popped. |
| 68 | push(rootInstanceStackCursor, nextRootInstance, fiber); |
| 69 | // Track the context and the Fiber that provided it. |
| 70 | // This enables us to pop only Fibers that provide unique contexts. |
| 71 | push(contextFiberStackCursor, fiber, fiber); |
| 72 | |
| 73 | // Finally, we need to push the host context to the stack. |
| 74 | // However, we can't just call getRootHostContext() and push it because |
| 75 | // we'd have a different number of entries on the stack depending on |
| 76 | // whether getRootHostContext() throws somewhere in renderer code or not. |
| 77 | // So we push an empty value first. This lets us safely unwind on errors. |
| 78 | push(contextStackCursor, null, fiber); |
| 79 | const nextRootContext = getRootHostContext(nextRootInstance); |
| 80 | // Now that we know this function doesn't throw, replace it. |
| 81 | pop(contextStackCursor, fiber); |
| 82 | push(contextStackCursor, nextRootContext, fiber); |
| 83 | } |
| 84 | |
| 85 | function popHostContainer(fiber: Fiber) { |
| 86 | pop(contextStackCursor, fiber); |
| 87 | pop(contextFiberStackCursor, fiber); |
| 88 | pop(rootInstanceStackCursor, fiber); |
| 89 | } |
| 90 | |
| 91 | function getHostContext(): HostContext { |
| 92 | const context = requiredContext(contextStackCursor.current); |
| 93 | return context; |
| 94 | } |
| 95 | |
| 96 | function pushHostContext(fiber: Fiber): void { |
| 97 | const stateHook: Hook | null = fiber.memoizedState; |
| 98 | if (stateHook !== null) { |
| 99 | // Propagate the current state to all the descendents. |
| 100 | // We use Context as an implementation detail for this. |
| 101 | // |
| 102 | // NOTE: This assumes that there cannot be nested transition providers, |
| 103 | // because the only renderer that implements this feature is React DOM, |
| 104 | // and forms cannot be nested. If we did support nested providers, then |
| 105 | // we would need to push a context value even for host fibers that |
| 106 | // haven't been upgraded yet. |
| 107 | const transitionStatus: TransitionStatus = stateHook.memoizedState; |
| 108 | // $FlowFixMe[constant-condition] |
| 109 | if (isPrimaryRenderer) { |
| 110 | HostTransitionContext._currentValue = transitionStatus; |
| 111 | } else { |
| 112 | HostTransitionContext._currentValue2 = transitionStatus; |
| 113 | } |
| 114 | |
| 115 | // Only provide context if this fiber has been upgraded by a host |
| 116 | // transition. We use the same optimization for regular host context below. |
| 117 | push(hostTransitionProviderCursor, fiber, fiber); |
| 118 | } |
| 119 | |
| 120 | const context: HostContext = requiredContext(contextStackCursor.current); |
| 121 | const nextContext = getChildHostContext(context, fiber.type); |
| 122 | |
| 123 | // Don't push this Fiber's context unless it's unique. |
| 124 | if (context !== nextContext) { |
| 125 | // Track the context and the Fiber that provided it. |
| 126 | // This enables us to pop only Fibers that provide unique contexts. |
| 127 | push(contextFiberStackCursor, fiber, fiber); |
| 128 | push(contextStackCursor, nextContext, fiber); |
| 129 | } |
| 130 | } |
| 131 | |
| 132 | function popHostContext(fiber: Fiber): void { |
| 133 | if (contextFiberStackCursor.current === fiber) { |
| 134 | // Do not pop unless this Fiber provided the current context. |
| 135 | // pushHostContext() only pushes Fibers that provide unique contexts. |
| 136 | pop(contextStackCursor, fiber); |
| 137 | pop(contextFiberStackCursor, fiber); |
| 138 | } |
| 139 | |
| 140 | if (hostTransitionProviderCursor.current === fiber) { |
| 141 | // Do not pop unless this Fiber provided the current context. This is mostly |
| 142 | // a performance optimization, but conveniently it also prevents a potential |
| 143 | // data race where a host provider is upgraded (i.e. memoizedState becomes |
| 144 | // non-null) during a concurrent event. This is a bit of a flaw in the way |
| 145 | // we upgrade host components, but because we're accounting for it here, it |
| 146 | // should be fine. |
| 147 | pop(hostTransitionProviderCursor, fiber); |
| 148 | |
| 149 | // When popping the transition provider, we reset the context value back |
| 150 | // to `NotPendingTransition`. We can do this because you're not allowed to nest forms. If |
| 151 | // we allowed for multiple nested host transition providers, then we'd |
| 152 | // need to reset this to the parent provider's status. |
| 153 | // $FlowFixMe[constant-condition] |
| 154 | if (isPrimaryRenderer) { |
| 155 | HostTransitionContext._currentValue = NotPendingTransition; |
| 156 | } else { |
| 157 | HostTransitionContext._currentValue2 = NotPendingTransition; |
| 158 | } |
| 159 | } |
| 160 | } |
| 161 | |
| 162 | export { |
| 163 | getHostContext, |
| 164 | getCurrentRootHostContainer, |
| 165 | getRootHostContainer, |
| 166 | popHostContainer, |
| 167 | popHostContext, |
| 168 | pushHostContainer, |
| 169 | pushHostContext, |
| 170 | }; |