| 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 | export type Destination = ReadableStreamController; |
| 11 | |
| 12 | export type PrecomputedChunk = Uint8Array; |
| 13 | export opaque type Chunk = Uint8Array; |
| 14 | export type BinaryChunk = Uint8Array; |
| 15 | |
| 16 | const channel = new MessageChannel(); |
| 17 | const taskQueue = []; |
| 18 | channel.port1.onmessage = () => { |
| 19 | const task = taskQueue.shift(); |
| 20 | if (task) { |
| 21 | task(); |
| 22 | } |
| 23 | }; |
| 24 | |
| 25 | export function scheduleWork(callback: () => void) { |
| 26 | taskQueue.push(callback); |
| 27 | channel.port2.postMessage(null); |
| 28 | } |
| 29 | |
| 30 | function handleErrorInNextTick(error: any) { |
| 31 | setTimeout(() => { |
| 32 | throw error; |
| 33 | }); |
| 34 | } |
| 35 | |
| 36 | const LocalPromise = Promise; |
| 37 | |
| 38 | export const scheduleMicrotask: (callback: () => void) => void = |
| 39 | typeof queueMicrotask === 'function' |
| 40 | ? queueMicrotask |
| 41 | : callback => { |
| 42 | LocalPromise.resolve(null).then(callback).catch(handleErrorInNextTick); |
| 43 | }; |
| 44 | |
| 45 | export function flushBuffered(destination: Destination) { |
| 46 | // WHATWG Streams do not yet have a way to flush the underlying |
| 47 | // transform streams. https://github.com/whatwg/streams/issues/960 |
| 48 | } |
| 49 | |
| 50 | const VIEW_SIZE = 2048; |
| 51 | let currentView = null; |
| 52 | let writtenBytes = 0; |
| 53 | |
| 54 | export function beginWriting(destination: Destination) { |
| 55 | currentView = new Uint8Array(VIEW_SIZE); |
| 56 | writtenBytes = 0; |
| 57 | } |
| 58 | |
| 59 | export function writeChunk( |
| 60 | destination: Destination, |
| 61 | chunk: PrecomputedChunk | Chunk | BinaryChunk, |
| 62 | ): void { |
| 63 | if (chunk.byteLength === 0) { |
| 64 | return; |
| 65 | } |
| 66 | |
| 67 | if (chunk.byteLength > VIEW_SIZE) { |
| 68 | // this chunk may overflow a single view which implies it was not |
| 69 | // one that is cached by the streaming renderer. We will enqueu |
| 70 | // it directly and expect it is not re-used |
| 71 | if (writtenBytes > 0) { |
| 72 | destination.enqueue( |
| 73 | new Uint8Array( |
| 74 | (currentView as any as Uint8Array).buffer, |
| 75 | 0, |
| 76 | writtenBytes, |
| 77 | ), |
| 78 | ); |
| 79 | currentView = new Uint8Array(VIEW_SIZE); |
| 80 | writtenBytes = 0; |
| 81 | } |
| 82 | destination.enqueue(chunk); |
| 83 | return; |
| 84 | } |
| 85 | |
| 86 | let bytesToWrite = chunk; |
| 87 | const allowableBytes = |
| 88 | (currentView as any as Uint8Array).length - writtenBytes; |
| 89 | if (allowableBytes < bytesToWrite.byteLength) { |
| 90 | // this chunk would overflow the current view. We enqueue a full view |
| 91 | // and start a new view with the remaining chunk |
| 92 | if (allowableBytes === 0) { |
| 93 | // the current view is already full, send it |
| 94 | destination.enqueue(currentView); |
| 95 | } else { |
| 96 | // fill up the current view and apply the remaining chunk bytes |
| 97 | // to a new view. |
| 98 | (currentView as any as Uint8Array).set( |
| 99 | bytesToWrite.subarray(0, allowableBytes), |
| 100 | writtenBytes, |
| 101 | ); |
| 102 | // writtenBytes += allowableBytes; // this can be skipped because we are going to immediately reset the view |
| 103 | destination.enqueue(currentView); |
| 104 | bytesToWrite = bytesToWrite.subarray(allowableBytes); |
| 105 | } |
| 106 | currentView = new Uint8Array(VIEW_SIZE); |
| 107 | writtenBytes = 0; |
| 108 | } |
| 109 | (currentView as any as Uint8Array).set(bytesToWrite, writtenBytes); |
| 110 | writtenBytes += bytesToWrite.byteLength; |
| 111 | } |
| 112 | |
| 113 | export function writeChunkAndReturn( |
| 114 | destination: Destination, |
| 115 | chunk: PrecomputedChunk | Chunk | BinaryChunk, |
| 116 | ): boolean { |
| 117 | writeChunk(destination, chunk); |
| 118 | // in web streams there is no backpressure so we can alwas write more |
| 119 | return true; |
| 120 | } |
| 121 | |
| 122 | export function completeWriting(destination: Destination) { |
| 123 | if (currentView && writtenBytes > 0) { |
| 124 | destination.enqueue(new Uint8Array(currentView.buffer, 0, writtenBytes)); |
| 125 | currentView = null; |
| 126 | writtenBytes = 0; |
| 127 | } |
| 128 | } |
| 129 | |
| 130 | export function close(destination: Destination) { |
| 131 | destination.close(); |
| 132 | } |
| 133 | |
| 134 | const textEncoder = new TextEncoder(); |
| 135 | |
| 136 | export function stringToChunk(content: string): Chunk { |
| 137 | return textEncoder.encode(content); |
| 138 | } |
| 139 | |
| 140 | export function stringToPrecomputedChunk(content: string): PrecomputedChunk { |
| 141 | const precomputedChunk = textEncoder.encode(content); |
| 142 | |
| 143 | if (__DEV__) { |
| 144 | if (precomputedChunk.byteLength > VIEW_SIZE) { |
| 145 | console.error( |
| 146 | 'precomputed chunks must be smaller than the view size configured for this host. This is a bug in React.', |
| 147 | ); |
| 148 | } |
| 149 | } |
| 150 | |
| 151 | return precomputedChunk; |
| 152 | } |
| 153 | |
| 154 | export function typedArrayToBinaryChunk( |
| 155 | content: $ArrayBufferView, |
| 156 | ): BinaryChunk { |
| 157 | // Convert any non-Uint8Array array to Uint8Array. We could avoid this for Uint8Arrays. |
| 158 | // If we passed through this straight to enqueue we wouldn't have to convert it but since |
| 159 | // we need to copy the buffer in that case, we need to convert it to copy it. |
| 160 | // When we copy it into another array using set() it needs to be a Uint8Array. |
| 161 | const buffer = new Uint8Array( |
| 162 | content.buffer, |
| 163 | content.byteOffset, |
| 164 | content.byteLength, |
| 165 | ); |
| 166 | // We clone large chunks so that we can transfer them when we write them. |
| 167 | // Others get copied into the target buffer. |
| 168 | return content.byteLength > VIEW_SIZE ? buffer.slice() : buffer; |
| 169 | } |
| 170 | |
| 171 | export function byteLengthOfChunk(chunk: Chunk | PrecomputedChunk): number { |
| 172 | return chunk.byteLength; |
| 173 | } |
| 174 | |
| 175 | export function byteLengthOfBinaryChunk(chunk: BinaryChunk): number { |
| 176 | return chunk.byteLength; |
| 177 | } |
| 178 | |
| 179 | export function closeWithError(destination: Destination, error: mixed): void { |
| 180 | // $FlowFixMe[method-unbinding] |
| 181 | if (typeof destination.error === 'function') { |
| 182 | // $FlowFixMe[incompatible-type]: This is an Error object or the destination accepts other types. |
| 183 | destination.error(error); |
| 184 | } else { |
| 185 | // Earlier implementations doesn't support this method. In that environment you're |
| 186 | // supposed to throw from a promise returned but we don't return a promise in our |
| 187 | // approach. We could fork this implementation but this is environment is an edge |
| 188 | // case to begin with. It's even less common to run this in an older environment. |
| 189 | // Even then, this is not where errors are supposed to happen and they get reported |
| 190 | // to a global callback in addition to this anyway. So it's fine just to close this. |
| 191 | destination.close(); |
| 192 | } |
| 193 | } |
| 194 | |
| 195 | export {createFastHashJS as createFastHash} from 'react-server/src/createFastHashJS'; |
| 196 | |
| 197 | export function readAsDataURL(blob: Blob): Promise<string> { |
| 198 | return new Promise((resolve, reject) => { |
| 199 | const reader = new FileReader(); |
| 200 | // $FlowFixMe[incompatible-type]: We always expect a string result with readAsDataURL. |
| 201 | reader.onloadend = () => resolve(reader.result); |
| 202 | reader.onerror = reject; |
| 203 | reader.readAsDataURL(blob); |
| 204 | }); |
| 205 | } |