| 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 {ReactContext} from 'shared/ReactTypes'; |
| 11 | |
| 12 | import * as React from 'react'; |
| 13 | import { |
| 14 | createContext, |
| 15 | startTransition, |
| 16 | unstable_useCacheRefresh as useCacheRefresh, |
| 17 | useCallback, |
| 18 | useContext, |
| 19 | useEffect, |
| 20 | useMemo, |
| 21 | useRef, |
| 22 | useState, |
| 23 | } from 'react'; |
| 24 | import {TreeStateContext} from './TreeContext'; |
| 25 | import {BridgeContext, StoreContext} from '../context'; |
| 26 | import { |
| 27 | inspectElement, |
| 28 | startElementUpdatesPolling, |
| 29 | } from 'react-devtools-shared/src/inspectedElementCache'; |
| 30 | import { |
| 31 | clearHookNamesCache, |
| 32 | hasAlreadyLoadedHookNames, |
| 33 | loadHookNames, |
| 34 | } from 'react-devtools-shared/src/hookNamesCache'; |
| 35 | import {loadModule} from 'react-devtools-shared/src/dynamicImportCache'; |
| 36 | import FetchFileWithCachingContext from 'react-devtools-shared/src/devtools/views/Components/FetchFileWithCachingContext'; |
| 37 | import HookNamesModuleLoaderContext from 'react-devtools-shared/src/devtools/views/Components/HookNamesModuleLoaderContext'; |
| 38 | import {SettingsContext} from '../Settings/SettingsContext'; |
| 39 | |
| 40 | import type {HookNames} from 'react-devtools-shared/src/frontend/types'; |
| 41 | import type {ReactNodeList} from 'shared/ReactTypes'; |
| 42 | import type { |
| 43 | Element, |
| 44 | InspectedElement, |
| 45 | } from 'react-devtools-shared/src/frontend/types'; |
| 46 | |
| 47 | type Path = Array<string | number>; |
| 48 | type InspectPathFunction = (path: Path) => void; |
| 49 | export type ToggleParseHookNames = () => void; |
| 50 | |
| 51 | type Context = { |
| 52 | hookNames: HookNames | null, |
| 53 | inspectedElement: InspectedElement | null, |
| 54 | inspectPaths: InspectPathFunction, |
| 55 | parseHookNames: boolean, |
| 56 | toggleParseHookNames: ToggleParseHookNames, |
| 57 | }; |
| 58 | |
| 59 | export const InspectedElementContext: ReactContext<Context> = |
| 60 | createContext<Context>(null as any as Context); |
| 61 | |
| 62 | export type Props = { |
| 63 | children: ReactNodeList, |
| 64 | }; |
| 65 | |
| 66 | export function InspectedElementContextController({ |
| 67 | children, |
| 68 | }: Props): React.Node { |
| 69 | const {inspectedElementID} = useContext(TreeStateContext); |
| 70 | const fetchFileWithCaching = useContext(FetchFileWithCachingContext); |
| 71 | const bridge = useContext(BridgeContext); |
| 72 | const store = useContext(StoreContext); |
| 73 | const {parseHookNames: parseHookNamesByDefault} = useContext(SettingsContext); |
| 74 | |
| 75 | // parseHookNames has a lot of code. |
| 76 | // Embedding it into a build makes the build large. |
| 77 | // This function enables DevTools to make use of Suspense to lazily import() it only if the feature will be used. |
| 78 | // TODO (Webpack 5) Hopefully we can remove this indirection once the Webpack 5 upgrade is completed. |
| 79 | const hookNamesModuleLoader = useContext(HookNamesModuleLoaderContext); |
| 80 | |
| 81 | const refresh = useCacheRefresh(); |
| 82 | |
| 83 | // Temporarily stores most recently-inspected (hydrated) path. |
| 84 | // The transition that updates this causes the component to re-render and ask the cache->backend for the new path. |
| 85 | // When a path is sent along with an "inspectElement" request, |
| 86 | // the backend knows to send its dehydrated data even if the element hasn't updated since the last request. |
| 87 | const [state, setState] = useState<{ |
| 88 | element: Element | null, |
| 89 | path: Array<number | string> | null, |
| 90 | }>({ |
| 91 | element: null, |
| 92 | path: null, |
| 93 | }); |
| 94 | |
| 95 | const element = |
| 96 | inspectedElementID !== null |
| 97 | ? store.getElementByID(inspectedElementID) |
| 98 | : null; |
| 99 | |
| 100 | const alreadyLoadedHookNames = |
| 101 | element != null && hasAlreadyLoadedHookNames(element); |
| 102 | |
| 103 | // Parse the currently inspected element's hook names. |
| 104 | // This may be enabled by default (for all elements) |
| 105 | // or it may be opted into on a per-element basis (if it's too slow to be on by default). |
| 106 | const [parseHookNames, setParseHookNames] = useState<boolean>( |
| 107 | parseHookNamesByDefault || alreadyLoadedHookNames, |
| 108 | ); |
| 109 | |
| 110 | const [bridgeIsAlive, setBridgeIsAliveStatus] = useState<boolean>(true); |
| 111 | |
| 112 | const elementHasChanged = element !== null && element !== state.element; |
| 113 | |
| 114 | // Reset the cached inspected paths when a new element is selected. |
| 115 | if (elementHasChanged) { |
| 116 | setState({ |
| 117 | element, |
| 118 | path: null, |
| 119 | }); |
| 120 | |
| 121 | setParseHookNames(parseHookNamesByDefault || alreadyLoadedHookNames); |
| 122 | } |
| 123 | |
| 124 | const purgeCachedMetadataRef = useRef(null); |
| 125 | |
| 126 | // Don't load a stale element from the backend; it wastes bridge bandwidth. |
| 127 | let hookNames: HookNames | null = null; |
| 128 | let inspectedElement = null; |
| 129 | if (!elementHasChanged && element !== null) { |
| 130 | inspectedElement = inspectElement(element, state.path, store, bridge); |
| 131 | |
| 132 | if (typeof hookNamesModuleLoader === 'function') { |
| 133 | if (parseHookNames || alreadyLoadedHookNames) { |
| 134 | const hookNamesModule = loadModule(hookNamesModuleLoader); |
| 135 | if (hookNamesModule !== null) { |
| 136 | const {parseHookNames: loadHookNamesFunction, purgeCachedMetadata} = |
| 137 | hookNamesModule; |
| 138 | |
| 139 | purgeCachedMetadataRef.current = purgeCachedMetadata; |
| 140 | |
| 141 | if ( |
| 142 | inspectedElement !== null && |
| 143 | inspectedElement.hooks !== null && |
| 144 | loadHookNamesFunction !== null |
| 145 | ) { |
| 146 | hookNames = loadHookNames( |
| 147 | element, |
| 148 | inspectedElement.hooks, |
| 149 | loadHookNamesFunction, |
| 150 | fetchFileWithCaching, |
| 151 | ); |
| 152 | } |
| 153 | } |
| 154 | } |
| 155 | } |
| 156 | } |
| 157 | |
| 158 | const toggleParseHookNames: ToggleParseHookNames = |
| 159 | useCallback<ToggleParseHookNames>(() => { |
| 160 | startTransition(() => { |
| 161 | setParseHookNames(value => !value); |
| 162 | refresh(); |
| 163 | }); |
| 164 | }, [setParseHookNames]); |
| 165 | |
| 166 | const inspectPaths: InspectPathFunction = useCallback<InspectPathFunction>( |
| 167 | (path: Path) => { |
| 168 | startTransition(() => { |
| 169 | setState({ |
| 170 | element: state.element, |
| 171 | path, |
| 172 | }); |
| 173 | refresh(); |
| 174 | }); |
| 175 | }, |
| 176 | [setState, state], |
| 177 | ); |
| 178 | |
| 179 | useEffect(() => { |
| 180 | const purgeCachedMetadata = purgeCachedMetadataRef.current; |
| 181 | if (typeof purgeCachedMetadata === 'function') { |
| 182 | // When Fast Refresh updates a component, any cached AST metadata may be invalid. |
| 183 | const fastRefreshScheduled = () => { |
| 184 | startTransition(() => { |
| 185 | clearHookNamesCache(); |
| 186 | purgeCachedMetadata(); |
| 187 | refresh(); |
| 188 | }); |
| 189 | }; |
| 190 | bridge.addListener('fastRefreshScheduled', fastRefreshScheduled); |
| 191 | return () => |
| 192 | bridge.removeListener('fastRefreshScheduled', fastRefreshScheduled); |
| 193 | } |
| 194 | }, [bridge]); |
| 195 | |
| 196 | // Reset path now that we've asked the backend to hydrate it. |
| 197 | // The backend is stateful, so we don't need to remember this path the next time we inspect. |
| 198 | useEffect(() => { |
| 199 | if (state.path !== null) { |
| 200 | setState({ |
| 201 | element: state.element, |
| 202 | path: null, |
| 203 | }); |
| 204 | } |
| 205 | }, [state]); |
| 206 | |
| 207 | useEffect(() => { |
| 208 | // Assuming that new bridge is always alive at this moment |
| 209 | setBridgeIsAliveStatus(true); |
| 210 | |
| 211 | const listener = () => setBridgeIsAliveStatus(false); |
| 212 | bridge.addListener('shutdown', listener); |
| 213 | |
| 214 | return () => bridge.removeListener('shutdown', listener); |
| 215 | }, [bridge]); |
| 216 | |
| 217 | // Periodically poll the selected element for updates. |
| 218 | useEffect(() => { |
| 219 | if (element !== null && bridgeIsAlive) { |
| 220 | const {abort, pause, resume} = startElementUpdatesPolling({ |
| 221 | bridge, |
| 222 | element, |
| 223 | refresh, |
| 224 | store, |
| 225 | }); |
| 226 | |
| 227 | bridge.addListener('resumeElementPolling', resume); |
| 228 | bridge.addListener('pauseElementPolling', pause); |
| 229 | |
| 230 | return () => { |
| 231 | bridge.removeListener('resumeElementPolling', resume); |
| 232 | bridge.removeListener('pauseElementPolling', pause); |
| 233 | |
| 234 | abort(); |
| 235 | }; |
| 236 | } |
| 237 | }, [ |
| 238 | element, |
| 239 | hookNames, |
| 240 | // Reset this timer any time the element we're inspecting gets a new response. |
| 241 | // No sense to ping right away after e.g. inspecting/hydrating a path. |
| 242 | inspectedElement, |
| 243 | state, |
| 244 | bridgeIsAlive, |
| 245 | ]); |
| 246 | |
| 247 | const value = useMemo<Context>( |
| 248 | () => ({ |
| 249 | hookNames, |
| 250 | inspectedElement, |
| 251 | inspectPaths, |
| 252 | parseHookNames, |
| 253 | toggleParseHookNames, |
| 254 | }), |
| 255 | [ |
| 256 | hookNames, |
| 257 | inspectedElement, |
| 258 | inspectPaths, |
| 259 | parseHookNames, |
| 260 | toggleParseHookNames, |
| 261 | ], |
| 262 | ); |
| 263 | |
| 264 | return ( |
| 265 | <InspectedElementContext.Provider value={value}> |
| 266 | {children} |
| 267 | </InspectedElementContext.Provider> |
| 268 | ); |
| 269 | } |