next.js/turbopack/crates/turbopack-node/js/src/transforms/webpack-loaders.ts

declare const __turbopack_external_require__: {
  resolve: (name: string, opt: { paths: string[] }) => string
} & ((id: string, thunk: () => any, esm?: boolean) => any)

import type { Ipc } from '../ipc/evaluate'
import { dirname, resolve as pathResolve } from 'path'
import {
  StackFrame,
  parse as parseStackTrace,
} from '../compiled/stacktrace-parser'
import { structuredError, type StructuredError } from '../ipc'
import {
  fromPath,
  getReadEnvVariables,
  toPath,
  type TransformIpc,
} from './transforms'

export type IpcInfoMessage =
  | {
      type: 'dependencies'
      envVariables?: string[]
      directories?: Array<[string, string]>
      filePaths?: string[]
      buildFilePaths?: string[]
    }
  | {
      type: 'emittedError'
      severity: 'warning' | 'error'
      error: StructuredError
    }
  | {
      type: 'log'
      logs: Array<{
        time: number
        logType: string
        args: any[]
        trace?: StackFrame[]
      }>
    }

export type IpcRequestMessage = {
  type: 'resolve'
  options: any
  lookupPath: string
  request: string
}

type LoaderConfig =
  | string
  | {
      loader: string
      options: { [k: string]: unknown }
    }

const {
  runLoaders,
}: typeof import('loader-runner') = require('@vercel/turbopack/loader-runner')

const contextDir = process.cwd()

const LogType = Object.freeze({
  error: 'error',
  warn: 'warn',
  info: 'info',
  log: 'log',
  debug: 'debug',

  trace: 'trace',

  group: 'group',
  groupCollapsed: 'groupCollapsed',
  groupEnd: 'groupEnd',

  profile: 'profile',
  profileEnd: 'profileEnd',

  time: 'time',

  clear: 'clear',
  status: 'status',
})

const loaderFlag = 'LOADER_EXECUTION'

const cutOffByFlag = (stack: string, flag: string): string => {
  const errorStack = stack.split('\n')
  for (let i = 0; i < errorStack.length; i++) {
    if (errorStack[i].includes(flag)) {
      errorStack.length = i
    }
  }
  return errorStack.join('\n')
}

/**
 * @param stack stack trace
 * @returns stack trace without the loader execution flag included
 */
const cutOffLoaderExecution = (stack: string): string =>
  cutOffByFlag(stack, loaderFlag)

class DummySpan {
  traceChild() {
    return new DummySpan()
  }

  traceFn<T>(fn: (span: DummySpan) => T): T {
    return fn(this)
  }

  async traceAsyncFn<T>(fn: (span: DummySpan) => T | Promise<T>): Promise<T> {
    return await fn(this)
  }

  stop() {
    return
  }
}

type ResolveOptions = {
  dependencyType?: string
  alias?: Record<string, string[]> | unknown[]
  aliasFields?: string[]
  cacheWithContext?: boolean
  conditionNames?: string[]
  descriptionFiles?: string[]
  enforceExtension?: boolean
  extensionAlias: Record<string, string[]>
  extensions?: string[]
  fallback?: Record<string, string[]>
  mainFields?: string[]
  mainFiles?: string[]
  exportsFields?: string[]
  modules?: string[]
  plugins?: unknown[]
  symlinks?: boolean
  unsafeCache?: boolean
  useSyncFileSystemCalls?: boolean
  preferRelative?: boolean
  preferAbsolute?: boolean
  restrictions?: unknown[]
  roots?: string[]
  importFields?: string[]
}

const transform = (
  ipc: TransformIpc,
  content: string | { binary: string },
  name: string,
  query: string,
  loaders: LoaderConfig[],
  sourceMap: boolean
) => {
  return new Promise((resolve, reject) => {
    const resource = pathResolve(contextDir, name)
    const resourceDir = dirname(resource)

    const loadersWithOptions = loaders.map((loader) =>
      typeof loader === 'string' ? { loader, options: {} } : loader
    )

    const logs: Array<{
      time: number
      logType: string
      args: unknown[]
      trace: StackFrame[] | undefined
    }> = []

    runLoaders(
      {
        resource: resource + query,
        context: {
          _module: {
            // For debugging purpose, if someone find context is not full compatible to
            // webpack they can guess this comes from turbopack
            __reserved: 'TurbopackContext',
          },
          currentTraceSpan: new DummySpan(),
          rootContext: contextDir,
          sourceMap,
          getOptions() {
            const entry = this.loaders[this.loaderIndex]
            return entry.options && typeof entry.options === 'object'
              ? entry.options
              : {}
          },
          getResolve: (options: ResolveOptions) => {
            const rustOptions = {
              aliasFields: undefined as undefined | string[],
              conditionNames: undefined as undefined | string[],
              noPackageJson: false,
              extensions: undefined as undefined | string[],
              mainFields: undefined as undefined | string[],
              noExportsField: false,
              mainFiles: undefined as undefined | string[],
              noModules: false,
              preferRelative: false,
            }
            if (options.alias) {
              if (!Array.isArray(options.alias) || options.alias.length > 0) {
                throw new Error('alias resolve option is not supported')
              }
            }
            if (options.aliasFields) {
              if (!Array.isArray(options.aliasFields)) {
                throw new Error('aliasFields resolve option must be an array')
              }
              rustOptions.aliasFields = options.aliasFields
            }
            if (options.conditionNames) {
              if (!Array.isArray(options.conditionNames)) {
                throw new Error(
                  'conditionNames resolve option must be an array'
                )
              }
              rustOptions.conditionNames = options.conditionNames
            }
            if (options.descriptionFiles) {
              if (
                !Array.isArray(options.descriptionFiles) ||
                options.descriptionFiles.length > 0
              ) {
                throw new Error(
                  'descriptionFiles resolve option is not supported'
                )
              }
              rustOptions.noPackageJson = true
            }
            if (options.extensions) {
              if (!Array.isArray(options.extensions)) {
                throw new Error('extensions resolve option must be an array')
              }
              rustOptions.extensions = options.extensions
            }
            if (options.mainFields) {
              if (!Array.isArray(options.mainFields)) {
                throw new Error('mainFields resolve option must be an array')
              }
              rustOptions.mainFields = options.mainFields
            }
            if (options.exportsFields) {
              if (
                !Array.isArray(options.exportsFields) ||
                options.exportsFields.length > 0
              ) {
                throw new Error('exportsFields resolve option is not supported')
              }
              rustOptions.noExportsField = true
            }
            if (options.mainFiles) {
              if (!Array.isArray(options.mainFiles)) {
                throw new Error('mainFiles resolve option must be an array')
              }
              rustOptions.mainFiles = options.mainFiles
            }
            if (options.modules) {
              if (
                !Array.isArray(options.modules) ||
                options.modules.length > 0
              ) {
                throw new Error('modules resolve option is not supported')
              }
              rustOptions.noModules = true
            }
            if (options.restrictions) {
              // TODO This is ignored for now
            }
            if (options.dependencyType) {
              // TODO This is ignored for now
            }
            if (options.preferRelative) {
              if (typeof options.preferRelative !== 'boolean') {
                throw new Error(
                  'preferRelative resolve option must be a boolean'
                )
              }
              rustOptions.preferRelative = options.preferRelative
            }
            return (
              lookupPath: string,
              request: string,
              callback?: (err?: Error, result?: string) => void
            ) => {
              const promise = ipc
                .sendRequest({
                  type: 'resolve',
                  options: rustOptions,
                  lookupPath: toPath(lookupPath),
                  request,
                })
                .then((unknownResult) => {
                  let result = unknownResult as { path: string }
                  if (result && typeof result.path === 'string') {
                    return fromPath(result.path)
                  } else {
                    throw Error(
                      'Expected { path: string } from resolve request'
                    )
                  }
                })
              if (callback) {
                promise
                  .then(
                    (result) => callback(undefined, result),
                    (err) => callback(err)
                  )
                  .catch((err) => {
                    ipc.sendError(err)
                  })
              } else {
                return promise
              }
            }
          },
          emitWarning: makeErrorEmitter('warning', ipc),
          emitError: makeErrorEmitter('error', ipc),
          getLogger(name: unknown) {
            const logFn = (logType: string, ...args: unknown[]) => {
              let trace: StackFrame[] | undefined
              switch (logType) {
                case LogType.warn:
                case LogType.error:
                case LogType.trace:
                case LogType.debug:
                  trace = parseStackTrace(
                    cutOffLoaderExecution(new Error('Trace').stack!)
                      .split('\n')
                      .slice(3)
                      .join('\n')
                  )
                  break
                default:
                  // TODO: do we need to handle this?
                  break
              }
              // Batch logs messages to be sent at the end
              logs.push({
                time: Date.now(),
                logType,
                args,
                trace,
              })
            }
            let timers: Map<string, [number, number]> | undefined
            let timersAggregates: Map<string, [number, number]> | undefined

            // See https://github.com/webpack/webpack/blob/a48c34b34d2d6c44f9b2b221d7baf278d34ac0be/lib/logging/Logger.js#L8
            return {
              error: logFn.bind(this, LogType.error),
              warn: logFn.bind(this, LogType.warn),
              info: logFn.bind(this, LogType.info),
              log: logFn.bind(this, LogType.log),
              debug: logFn.bind(this, LogType.debug),
              assert: (assertion: boolean, ...args: any[]) => {
                if (!assertion) {
                  logFn(LogType.error, ...args)
                }
              },
              trace: logFn.bind(this, LogType.trace),
              clear: logFn.bind(this, LogType.clear),
              status: logFn.bind(this, LogType.status),
              group: logFn.bind(this, LogType.group),
              groupCollapsed: logFn.bind(this, LogType.groupCollapsed),
              groupEnd: logFn.bind(this, LogType.groupEnd),
              profile: logFn.bind(this, LogType.profile),
              profileEnd: logFn.bind(this, LogType.profileEnd),
              time: (label: string) => {
                timers = timers || new Map()
                timers.set(label, process.hrtime())
              },
              timeLog: (label: string) => {
                const prev = timers && timers.get(label)
                if (!prev) {
                  throw new Error(
                    `No such label '${label}' for WebpackLogger.timeLog()`
                  )
                }
                const time = process.hrtime(prev)
                logFn(LogType.time, [label, ...time])
              },
              timeEnd: (label: string) => {
                const prev = timers && timers.get(label)
                if (!prev) {
                  throw new Error(
                    `No such label '${label}' for WebpackLogger.timeEnd()`
                  )
                }
                const time = process.hrtime(prev)
                /** @type {Map<string | undefined, [number, number]>} */
                timers!.delete(label)
                logFn(LogType.time, [label, ...time])
              },
              timeAggregate: (label: string) => {
                const prev = timers && timers.get(label)
                if (!prev) {
                  throw new Error(
                    `No such label '${label}' for WebpackLogger.timeAggregate()`
                  )
                }
                const time = process.hrtime(prev)
                /** @type {Map<string | undefined, [number, number]>} */
                timers!.delete(label)
                /** @type {Map<string | undefined, [number, number]>} */
                timersAggregates = timersAggregates || new Map()
                const current = timersAggregates.get(label)
                if (current !== undefined) {
                  if (time[1] + current[1] > 1e9) {
                    time[0] += current[0] + 1
                    time[1] = time[1] - 1e9 + current[1]
                  } else {
                    time[0] += current[0]
                    time[1] += current[1]
                  }
                }
                timersAggregates.set(label, time)
              },
              timeAggregateEnd: (label: string) => {
                if (timersAggregates === undefined) return
                const time = timersAggregates.get(label)
                if (time === undefined) return
                timersAggregates.delete(label)
                logFn(LogType.time, [label, ...time])
              },
            }
          },
        },

        loaders: loadersWithOptions.map((loader) => ({
          loader: __turbopack_external_require__.resolve(loader.loader, {
            paths: [resourceDir],
          }),
          options: loader.options,
        })),
        readResource: (_filename, callback) => {
          // TODO assuming that filename === resource, but loaders might change that
          let data =
            typeof content === 'string'
              ? Buffer.from(content, 'utf-8')
              : Buffer.from(content.binary, 'base64')
          callback(null, data)
        },
      },
      (err, result) => {
        if (logs.length) {
          ipc.sendInfo({ type: 'log', logs: logs })
          logs.length = 0
        }
        ipc.sendInfo({
          type: 'dependencies',
          envVariables: getReadEnvVariables(),
          filePaths: result.fileDependencies.map(toPath),
          directories: result.contextDependencies.map((dep) => [
            toPath(dep),
            '**',
          ]),
        })
        if (err) return reject(err)
        if (!result.result) return reject(new Error('No result from loaders'))
        const [source, map] = result.result
        resolve({
          source: Buffer.isBuffer(source)
            ? { binary: source.toString('base64') }
            : source,
          map:
            typeof map === 'string'
              ? map
              : typeof map === 'object'
                ? JSON.stringify(map)
                : undefined,
        })
      }
    )
  })
}

export { transform as default }

function makeErrorEmitter(
  severity: 'warning' | 'error',
  ipc: Ipc<IpcInfoMessage, IpcRequestMessage>
) {
  return function (error: Error | string) {
    ipc.sendInfo({
      type: 'emittedError',
      severity: severity,
      error: structuredError(error),
    })
  }
}