| 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 {Writable} from 'stream'; |
| 11 | |
| 12 | import {TextEncoder} from 'util'; |
| 13 | import {createHash} from 'crypto'; |
| 14 | |
| 15 | interface MightBeFlushable { |
| 16 | flush?: () => void; |
| 17 | } |
| 18 | |
| 19 | export type Destination = Writable & MightBeFlushable; |
| 20 | |
| 21 | export type PrecomputedChunk = Uint8Array; |
| 22 | export opaque type Chunk = string; |
| 23 | export type BinaryChunk = Uint8Array; |
| 24 | |
| 25 | export function scheduleWork(callback: () => void) { |
| 26 | setImmediate(callback); |
| 27 | } |
| 28 | |
| 29 | export const scheduleMicrotask = queueMicrotask; |
| 30 | |
| 31 | export function flushBuffered(destination: Destination) { |
| 32 | // If we don't have any more data to send right now. |
| 33 | // Flush whatever is in the buffer to the wire. |
| 34 | if (typeof destination.flush === 'function') { |
| 35 | // By convention the Zlib streams provide a flush function for this purpose. |
| 36 | // For Express, compression middleware adds this method. |
| 37 | destination.flush(); |
| 38 | } |
| 39 | } |
| 40 | |
| 41 | // Chunks larger than VIEW_SIZE are written directly, without copying into the |
| 42 | // internal view buffer. This must be at least half of Node's internal Buffer |
| 43 | // pool size (8192) to avoid corrupting the pool when using |
| 44 | // renderToReadableStream, which uses a byte stream that detaches ArrayBuffers. |
| 45 | const VIEW_SIZE = 4096; |
| 46 | let currentView = null; |
| 47 | let writtenBytes = 0; |
| 48 | let destinationHasCapacity = true; |
| 49 | |
| 50 | export function beginWriting(destination: Destination) { |
| 51 | currentView = new Uint8Array(VIEW_SIZE); |
| 52 | writtenBytes = 0; |
| 53 | destinationHasCapacity = true; |
| 54 | } |
| 55 | |
| 56 | function writeStringChunk(destination: Destination, stringChunk: string) { |
| 57 | if (stringChunk.length === 0) { |
| 58 | return; |
| 59 | } |
| 60 | // maximum possible view needed to encode entire string |
| 61 | if (stringChunk.length * 3 > VIEW_SIZE) { |
| 62 | if (writtenBytes > 0) { |
| 63 | writeToDestination( |
| 64 | destination, |
| 65 | (currentView as any as Uint8Array).subarray(0, writtenBytes), |
| 66 | ); |
| 67 | currentView = new Uint8Array(VIEW_SIZE); |
| 68 | writtenBytes = 0; |
| 69 | } |
| 70 | // Write the raw string chunk and let the consumer handle the encoding. |
| 71 | writeToDestination(destination, stringChunk); |
| 72 | return; |
| 73 | } |
| 74 | |
| 75 | let target: Uint8Array = currentView as any; |
| 76 | if (writtenBytes > 0) { |
| 77 | target = (currentView as any as Uint8Array).subarray(writtenBytes); |
| 78 | } |
| 79 | const {read, written} = textEncoder.encodeInto(stringChunk, target); |
| 80 | writtenBytes += written; |
| 81 | |
| 82 | if (read < stringChunk.length) { |
| 83 | writeToDestination( |
| 84 | destination, |
| 85 | (currentView as any).subarray(0, writtenBytes), |
| 86 | ); |
| 87 | currentView = new Uint8Array(VIEW_SIZE); |
| 88 | writtenBytes = textEncoder.encodeInto( |
| 89 | stringChunk.slice(read), |
| 90 | currentView as any, |
| 91 | ).written; |
| 92 | } |
| 93 | |
| 94 | if (writtenBytes === VIEW_SIZE) { |
| 95 | writeToDestination(destination, currentView as any); |
| 96 | currentView = new Uint8Array(VIEW_SIZE); |
| 97 | writtenBytes = 0; |
| 98 | } |
| 99 | } |
| 100 | |
| 101 | function writeViewChunk( |
| 102 | destination: Destination, |
| 103 | chunk: PrecomputedChunk | BinaryChunk, |
| 104 | ) { |
| 105 | if (chunk.byteLength === 0) { |
| 106 | return; |
| 107 | } |
| 108 | if (chunk.byteLength > VIEW_SIZE) { |
| 109 | // this chunk may overflow a single view which implies it was not |
| 110 | // one that is cached by the streaming renderer. We will enqueu |
| 111 | // it directly and expect it is not re-used |
| 112 | if (writtenBytes > 0) { |
| 113 | writeToDestination( |
| 114 | destination, |
| 115 | (currentView as any as Uint8Array).subarray(0, writtenBytes), |
| 116 | ); |
| 117 | currentView = new Uint8Array(VIEW_SIZE); |
| 118 | writtenBytes = 0; |
| 119 | } |
| 120 | writeToDestination(destination, chunk); |
| 121 | return; |
| 122 | } |
| 123 | |
| 124 | let bytesToWrite = chunk; |
| 125 | const allowableBytes = |
| 126 | (currentView as any as Uint8Array).length - writtenBytes; |
| 127 | if (allowableBytes < bytesToWrite.byteLength) { |
| 128 | // this chunk would overflow the current view. We enqueue a full view |
| 129 | // and start a new view with the remaining chunk |
| 130 | if (allowableBytes === 0) { |
| 131 | // the current view is already full, send it |
| 132 | writeToDestination(destination, currentView as any); |
| 133 | } else { |
| 134 | // fill up the current view and apply the remaining chunk bytes |
| 135 | // to a new view. |
| 136 | (currentView as any as Uint8Array).set( |
| 137 | bytesToWrite.subarray(0, allowableBytes), |
| 138 | writtenBytes, |
| 139 | ); |
| 140 | writtenBytes += allowableBytes; |
| 141 | writeToDestination(destination, currentView as any); |
| 142 | bytesToWrite = bytesToWrite.subarray(allowableBytes); |
| 143 | } |
| 144 | currentView = new Uint8Array(VIEW_SIZE); |
| 145 | writtenBytes = 0; |
| 146 | } |
| 147 | (currentView as any as Uint8Array).set(bytesToWrite, writtenBytes); |
| 148 | writtenBytes += bytesToWrite.byteLength; |
| 149 | |
| 150 | if (writtenBytes === VIEW_SIZE) { |
| 151 | writeToDestination(destination, currentView as any); |
| 152 | currentView = new Uint8Array(VIEW_SIZE); |
| 153 | writtenBytes = 0; |
| 154 | } |
| 155 | } |
| 156 | |
| 157 | export function writeChunk( |
| 158 | destination: Destination, |
| 159 | chunk: PrecomputedChunk | Chunk | BinaryChunk, |
| 160 | ): void { |
| 161 | if (typeof chunk === 'string') { |
| 162 | writeStringChunk(destination, chunk); |
| 163 | } else { |
| 164 | writeViewChunk(destination, chunk as any as PrecomputedChunk | BinaryChunk); |
| 165 | } |
| 166 | } |
| 167 | |
| 168 | function writeToDestination( |
| 169 | destination: Destination, |
| 170 | view: string | Uint8Array, |
| 171 | ) { |
| 172 | const currentHasCapacity = destination.write(view); |
| 173 | destinationHasCapacity = destinationHasCapacity && currentHasCapacity; |
| 174 | } |
| 175 | |
| 176 | export function writeChunkAndReturn( |
| 177 | destination: Destination, |
| 178 | chunk: PrecomputedChunk | Chunk, |
| 179 | ): boolean { |
| 180 | writeChunk(destination, chunk); |
| 181 | return destinationHasCapacity; |
| 182 | } |
| 183 | |
| 184 | export function completeWriting(destination: Destination) { |
| 185 | if (currentView && writtenBytes > 0) { |
| 186 | destination.write(currentView.subarray(0, writtenBytes)); |
| 187 | } |
| 188 | currentView = null; |
| 189 | writtenBytes = 0; |
| 190 | destinationHasCapacity = true; |
| 191 | } |
| 192 | |
| 193 | export function close(destination: Destination) { |
| 194 | destination.end(); |
| 195 | } |
| 196 | |
| 197 | export const textEncoder: TextEncoder = new TextEncoder(); |
| 198 | |
| 199 | export function stringToChunk(content: string): Chunk { |
| 200 | return content; |
| 201 | } |
| 202 | |
| 203 | export function stringToPrecomputedChunk(content: string): PrecomputedChunk { |
| 204 | const precomputedChunk = textEncoder.encode(content); |
| 205 | |
| 206 | if (__DEV__) { |
| 207 | if (precomputedChunk.byteLength > VIEW_SIZE) { |
| 208 | console.error( |
| 209 | 'precomputed chunks must be smaller than the view size configured for this host. This is a bug in React.', |
| 210 | ); |
| 211 | } |
| 212 | } |
| 213 | |
| 214 | return precomputedChunk; |
| 215 | } |
| 216 | |
| 217 | export function typedArrayToBinaryChunk( |
| 218 | content: $ArrayBufferView, |
| 219 | ): BinaryChunk { |
| 220 | // Convert any non-Uint8Array array to Uint8Array. We could avoid this for Uint8Arrays. |
| 221 | return new Uint8Array(content.buffer, content.byteOffset, content.byteLength); |
| 222 | } |
| 223 | |
| 224 | export function byteLengthOfChunk(chunk: Chunk | PrecomputedChunk): number { |
| 225 | return typeof chunk === 'string' |
| 226 | ? Buffer.byteLength(chunk, 'utf8') |
| 227 | : chunk.byteLength; |
| 228 | } |
| 229 | |
| 230 | export function byteLengthOfBinaryChunk(chunk: BinaryChunk): number { |
| 231 | return chunk.byteLength; |
| 232 | } |
| 233 | |
| 234 | export function closeWithError(destination: Destination, error: mixed): void { |
| 235 | // $FlowFixMe[incompatible-type]: This is an Error object or the destination accepts other types. |
| 236 | destination.destroy(error); |
| 237 | } |
| 238 | |
| 239 | export function createFastHash(input: string): string | number { |
| 240 | const hash = createHash('md5'); |
| 241 | hash.update(input); |
| 242 | return hash.digest('hex'); |
| 243 | } |
| 244 | |
| 245 | export function readAsDataURL(blob: Blob): Promise<string> { |
| 246 | return blob.arrayBuffer().then(arrayBuffer => { |
| 247 | const encoded = Buffer.from(arrayBuffer).toString('base64'); |
| 248 | const mimeType = blob.type || 'application/octet-stream'; |
| 249 | return 'data:' + mimeType + ';base64,' + encoded; |
| 250 | }); |
| 251 | } |