/opt/canhelp/node_modules/next/dist/esm/server/stream-utils
Edit: /opt/canhelp/node_modules/next/dist/esm/server/stream-utils/node-web-streams-helper.js.map (43514B)
{"version":3,"sources":["../../../src/server/stream-utils/node-web-streams-helper.ts"],"sourcesContent":["import type { ReactDOMServerReadableStream } from 'react-dom/server'\nimport { getTracer } from '../lib/trace/tracer'\nimport { AppRenderSpan } from '../lib/trace/constants'\nimport { DetachedPromise } from '../../lib/detached-promise'\nimport { scheduleImmediate, atLeastOneTask } from '../../lib/scheduler'\nimport { ENCODED_TAGS } from './encoded-tags'\nimport {\n indexOfUint8Array,\n isEquivalentUint8Arrays,\n removeFromUint8Array,\n} from './uint8array-helpers'\nimport { MISSING_ROOT_TAGS_ERROR } from '../../shared/lib/errors/constants'\nimport { insertBuildIdComment } from '../../shared/lib/segment-cache/output-export-prefetch-encoding'\n\nfunction voidCatch() {\n // this catcher is designed to be used with pipeTo where we expect the underlying\n // pipe implementation to forward errors but we don't want the pipeTo promise to reject\n // and be unhandled\n}\n\n// We can share the same encoder instance everywhere\n// Notably we cannot do the same for TextDecoder because it is stateful\n// when handling streaming data\nconst encoder = new TextEncoder()\n\nexport function chainStreams
(\n ...streams: ReadableStream[]\n): ReadableStream {\n // If we have no streams, return an empty stream. This behavior is\n // intentional as we're now providing the `RenderResult.EMPTY` value.\n if (streams.length === 0) {\n return new ReadableStream({\n start(controller) {\n controller.close()\n },\n })\n }\n\n // If we only have 1 stream we fast path it by returning just this stream\n if (streams.length === 1) {\n return streams[0]\n }\n\n const { readable, writable } = new TransformStream()\n\n // We always initiate pipeTo immediately. We know we have at least 2 streams\n // so we need to avoid closing the writable when this one finishes.\n let promise = streams[0].pipeTo(writable, { preventClose: true })\n\n let i = 1\n for (; i < streams.length - 1; i++) {\n const nextStream = streams[i]\n promise = promise.then(() =>\n nextStream.pipeTo(writable, { preventClose: true })\n )\n }\n\n // We can omit the length check because we halted before the last stream and there\n // is at least two streams so the lastStream here will always be defined\n const lastStream = streams[i]\n promise = promise.then(() => lastStream.pipeTo(writable))\n\n // Catch any errors from the streams and ignore them, they will be handled\n // by whatever is consuming the readable stream.\n promise.catch(voidCatch)\n\n return readable\n}\n\nexport function streamFromString(str: string): ReadableStream {\n return new ReadableStream({\n start(controller) {\n controller.enqueue(encoder.encode(str))\n controller.close()\n },\n })\n}\n\nexport function streamFromBuffer(chunk: Buffer): ReadableStream {\n return new ReadableStream({\n start(controller) {\n controller.enqueue(chunk)\n controller.close()\n },\n })\n}\n\nexport async function streamToBuffer(\n stream: ReadableStream\n): Promise {\n const reader = stream.getReader()\n const chunks: Uint8Array[] = []\n\n while (true) {\n const { done, value } = await reader.read()\n if (done) {\n break\n }\n\n chunks.push(value)\n }\n\n return Buffer.concat(chunks)\n}\n\nexport async function streamToString(\n stream: ReadableStream,\n signal?: AbortSignal\n): Promise {\n const decoder = new TextDecoder('utf-8', { fatal: true })\n let string = ''\n\n for await (const chunk of stream) {\n if (signal?.aborted) {\n return string\n }\n\n string += decoder.decode(chunk, { stream: true })\n }\n\n string += decoder.decode()\n\n return string\n}\n\nexport function createBufferedTransformStream(): TransformStream<\n Uint8Array,\n Uint8Array\n> {\n let bufferedChunks: Array = []\n let bufferByteLength: number = 0\n let pending: DetachedPromise | undefined\n\n const flush = (controller: TransformStreamDefaultController) => {\n // If we already have a pending flush, then return early.\n if (pending) return\n\n const detached = new DetachedPromise()\n pending = detached\n\n scheduleImmediate(() => {\n try {\n const chunk = new Uint8Array(bufferByteLength)\n let copiedBytes = 0\n\n for (let i = 0; i < bufferedChunks.length; i++) {\n const bufferedChunk = bufferedChunks[i]\n chunk.set(bufferedChunk, copiedBytes)\n copiedBytes += bufferedChunk.byteLength\n }\n // We just wrote all the buffered chunks so we need to reset the bufferedChunks array\n // and our bufferByteLength to prepare for the next round of buffered chunks\n bufferedChunks.length = 0\n bufferByteLength = 0\n controller.enqueue(chunk)\n } catch {\n // If an error occurs while enqueuing it can't be due to this\n // transformers fault. It's likely due to the controller being\n // errored due to the stream being cancelled.\n } finally {\n pending = undefined\n detached.resolve()\n }\n })\n }\n\n return new TransformStream({\n transform(chunk, controller) {\n // Combine the previous buffer with the new chunk.\n bufferedChunks.push(chunk)\n bufferByteLength += chunk.byteLength\n\n // Flush the buffer to the controller.\n flush(controller)\n },\n flush() {\n if (!pending) return\n\n return pending.promise\n },\n })\n}\n\nfunction createPrefetchCommentStream(\n isBuildTimePrerendering: boolean,\n buildId: string\n): TransformStream {\n // Insert an extra comment at the beginning of the HTML document. This must\n // come after the DOCTYPE, which is inserted by React.\n //\n // The first chunk sent by React will contain the doctype. After that, we can\n // pass through the rest of the chunks as-is.\n let didTransformFirstChunk = false\n return new TransformStream({\n transform(chunk, controller) {\n if (isBuildTimePrerendering && !didTransformFirstChunk) {\n didTransformFirstChunk = true\n const decoder = new TextDecoder('utf-8', { fatal: true })\n const chunkStr = decoder.decode(chunk, {\n stream: true,\n })\n const updatedChunkStr = insertBuildIdComment(chunkStr, buildId)\n controller.enqueue(encoder.encode(updatedChunkStr))\n return\n }\n controller.enqueue(chunk)\n },\n })\n}\n\nexport function renderToInitialFizzStream({\n ReactDOMServer,\n element,\n streamOptions,\n}: {\n ReactDOMServer: {\n renderToReadableStream: typeof import('react-dom/server').renderToReadableStream\n }\n element: React.ReactElement\n streamOptions?: Parameters[1]\n}): Promise {\n return getTracer().trace(AppRenderSpan.renderToReadableStream, async () =>\n ReactDOMServer.renderToReadableStream(element, streamOptions)\n )\n}\n\nfunction createMetadataTransformStream(\n insert: () => Promise | string\n): TransformStream {\n let chunkIndex = -1\n let isMarkRemoved = false\n\n return new TransformStream({\n async transform(chunk, controller) {\n let iconMarkIndex = -1\n let closedHeadIndex = -1\n chunkIndex++\n\n if (isMarkRemoved) {\n controller.enqueue(chunk)\n return\n }\n let iconMarkLength = 0\n // Only search for the closed head tag once\n if (iconMarkIndex === -1) {\n iconMarkIndex = indexOfUint8Array(chunk, ENCODED_TAGS.META.ICON_MARK)\n if (iconMarkIndex === -1) {\n controller.enqueue(chunk)\n return\n } else {\n // When we found the `` or `>`, checking the next char to ensure we cover both cases.\n iconMarkLength = ENCODED_TAGS.META.ICON_MARK.length\n // Check if next char is /, this is for xml mode.\n if (chunk[iconMarkIndex + iconMarkLength] === 47) {\n iconMarkLength += 2\n } else {\n // The last char is `>`\n iconMarkLength++\n }\n }\n }\n\n // Check if icon mark is inside tag in the first chunk.\n if (chunkIndex === 0) {\n closedHeadIndex = indexOfUint8Array(chunk, ENCODED_TAGS.CLOSED.HEAD)\n if (iconMarkIndex !== -1) {\n // The mark icon is located in the 1st chunk before the head tag.\n // We do not need to insert the script tag in this case because it's in the head.\n // Just remove the icon mark from the chunk.\n if (iconMarkIndex < closedHeadIndex) {\n const replaced = new Uint8Array(chunk.length - iconMarkLength)\n\n // Remove the icon mark from the chunk.\n replaced.set(chunk.subarray(0, iconMarkIndex))\n replaced.set(\n chunk.subarray(iconMarkIndex + iconMarkLength),\n iconMarkIndex\n )\n chunk = replaced\n } else {\n // The icon mark is after the head tag, replace and insert the script tag at that position.\n const insertion = await insert()\n const encodedInsertion = encoder.encode(insertion)\n const insertionLength = encodedInsertion.length\n const replaced = new Uint8Array(\n chunk.length - iconMarkLength + insertionLength\n )\n replaced.set(chunk.subarray(0, iconMarkIndex))\n replaced.set(encodedInsertion, iconMarkIndex)\n replaced.set(\n chunk.subarray(iconMarkIndex + iconMarkLength),\n iconMarkIndex + insertionLength\n )\n chunk = replaced\n }\n isMarkRemoved = true\n }\n // If there's no icon mark located, it will be handled later when if present in the following chunks.\n } else {\n // When it's appeared in the following chunks, we'll need to\n // remove the mark and then insert the script tag at that position.\n const insertion = await insert()\n const encodedInsertion = encoder.encode(insertion)\n const insertionLength = encodedInsertion.length\n // Replace the icon mark with the hoist script or empty string.\n const replaced = new Uint8Array(\n chunk.length - iconMarkLength + insertionLength\n )\n // Set the first part of the chunk, before the icon mark.\n replaced.set(chunk.subarray(0, iconMarkIndex))\n // Set the insertion after the icon mark.\n replaced.set(encodedInsertion, iconMarkIndex)\n\n // Set the rest of the chunk after the icon mark.\n replaced.set(\n chunk.subarray(iconMarkIndex + iconMarkLength),\n iconMarkIndex + insertionLength\n )\n chunk = replaced\n isMarkRemoved = true\n }\n controller.enqueue(chunk)\n },\n })\n}\n\nfunction createHeadInsertionTransformStream(\n insert: () => Promise\n): TransformStream {\n let inserted = false\n\n // We need to track if this transform saw any bytes because if it didn't\n // we won't want to insert any server HTML at all\n let hasBytes = false\n\n return new TransformStream({\n async transform(chunk, controller) {\n hasBytes = true\n\n const insertion = await insert()\n if (inserted) {\n if (insertion) {\n const encodedInsertion = encoder.encode(insertion)\n controller.enqueue(encodedInsertion)\n }\n controller.enqueue(chunk)\n } else {\n // TODO (@Ethan-Arrowood): Replace the generic `indexOfUint8Array` method with something finely tuned for the subset of things actually being checked for.\n const index = indexOfUint8Array(chunk, ENCODED_TAGS.CLOSED.HEAD)\n // In fully static rendering or non PPR rendering cases:\n // `/head>` will always be found in the chunk in first chunk rendering.\n if (index !== -1) {\n if (insertion) {\n const encodedInsertion = encoder.encode(insertion)\n // Get the total count of the bytes in the chunk and the insertion\n // e.g.\n // chunk = \n // insertion = \n // output = [ ] \n const insertedHeadContent = new Uint8Array(\n chunk.length + encodedInsertion.length\n )\n // Append the first part of the chunk, before the head tag\n insertedHeadContent.set(chunk.slice(0, index))\n // Append the server inserted content\n insertedHeadContent.set(encodedInsertion, index)\n // Append the rest of the chunk\n insertedHeadContent.set(\n chunk.slice(index),\n index + encodedInsertion.length\n )\n controller.enqueue(insertedHeadContent)\n } else {\n controller.enqueue(chunk)\n }\n inserted = true\n } else {\n // This will happens in PPR rendering during next start, when the page is partially rendered.\n // When the page resumes, the head tag will be found in the middle of the chunk.\n // Where we just need to append the insertion and chunk to the current stream.\n // e.g.\n // PPR-static: ... [ resume content ] \n // PPR-resume: [ insertion ] [ rest content ]\n if (insertion) {\n controller.enqueue(encoder.encode(insertion))\n }\n controller.enqueue(chunk)\n inserted = true\n }\n }\n },\n async flush(controller) {\n // Check before closing if there's anything remaining to insert.\n if (hasBytes) {\n const insertion = await insert()\n if (insertion) {\n controller.enqueue(encoder.encode(insertion))\n }\n }\n },\n })\n}\n\n// Suffix after main body content - scripts before ,\n// but wait for the major chunks to be enqueued.\nfunction createDeferredSuffixStream(\n suffix: string\n): TransformStream {\n let flushed = false\n let pending: DetachedPromise | undefined\n\n const flush = (controller: TransformStreamDefaultController) => {\n const detached = new DetachedPromise()\n pending = detached\n\n scheduleImmediate(() => {\n try {\n controller.enqueue(encoder.encode(suffix))\n } catch {\n // If an error occurs while enqueuing it can't be due to this\n // transformers fault. It's likely due to the controller being\n // errored due to the stream being cancelled.\n } finally {\n pending = undefined\n detached.resolve()\n }\n })\n }\n\n return new TransformStream({\n transform(chunk, controller) {\n controller.enqueue(chunk)\n\n // If we've already flushed, we're done.\n if (flushed) return\n\n // Schedule the flush to happen.\n flushed = true\n flush(controller)\n },\n flush(controller) {\n if (pending) return pending.promise\n if (flushed) return\n\n // Flush now.\n controller.enqueue(encoder.encode(suffix))\n },\n })\n}\n\nfunction createFlightDataInjectionTransformStream(\n stream: ReadableStream,\n delayDataUntilFirstHtmlChunk: boolean\n): TransformStream {\n let htmlStreamFinished = false\n\n let pull: Promise | null = null\n let donePulling = false\n\n function startOrContinuePulling(\n controller: TransformStreamDefaultController\n ) {\n if (!pull) {\n pull = startPulling(controller)\n }\n return pull\n }\n\n async function startPulling(controller: TransformStreamDefaultController) {\n const reader = stream.getReader()\n\n if (delayDataUntilFirstHtmlChunk) {\n // NOTE: streaming flush\n // We are buffering here for the inlined data stream because the\n // \"shell\" stream might be chunkenized again by the underlying stream\n // implementation, e.g. with a specific high-water mark. To ensure it's\n // the safe timing to pipe the data stream, this extra tick is\n // necessary.\n\n // We don't start reading until we've left the current Task to ensure\n // that it's inserted after flushing the shell. Note that this implementation\n // might get stale if impl details of Fizz change in the future.\n await atLeastOneTask()\n }\n\n try {\n while (true) {\n const { done, value } = await reader.read()\n if (done) {\n donePulling = true\n return\n }\n\n // We want to prioritize HTML over RSC data.\n // The SSR render is based on the same RSC stream, so when we get a new RSC chunk,\n // we're likely to produce an HTML chunk as well, so give it a chance to flush first.\n if (!delayDataUntilFirstHtmlChunk && !htmlStreamFinished) {\n await atLeastOneTask()\n }\n controller.enqueue(value)\n }\n } catch (err) {\n controller.error(err)\n }\n }\n\n return new TransformStream({\n start(controller) {\n if (!delayDataUntilFirstHtmlChunk) {\n startOrContinuePulling(controller)\n }\n },\n transform(chunk, controller) {\n controller.enqueue(chunk)\n\n // Start the streaming if it hasn't already been started yet.\n if (delayDataUntilFirstHtmlChunk) {\n startOrContinuePulling(controller)\n }\n },\n flush(controller) {\n htmlStreamFinished = true\n if (donePulling) {\n return\n }\n return startOrContinuePulling(controller)\n },\n })\n}\n\nconst CLOSE_TAG = '