1 files changed, 322 insertions, 0 deletions
diff --git a/lib/api/readable.js b/lib/api/readable.js
new file mode 100644
index 0000000..5269dfa
--- /dev/null
+++ b/lib/api/readable.js
@@ -0,0 +1,322 @@
+// Ported from https://github.com/nodejs/undici/pull/907
+
+'use strict'
+
+const assert = require('assert')
+const { Readable } = require('stream')
+const { RequestAbortedError, NotSupportedError, InvalidArgumentError } = require('../core/errors')
+const util = require('../core/util')
+const { ReadableStreamFrom, toUSVString } = require('../core/util')
+
+let Blob
+
+const kConsume = Symbol('kConsume')
+const kReading = Symbol('kReading')
+const kBody = Symbol('kBody')
+const kAbort = Symbol('abort')
+const kContentType = Symbol('kContentType')
+
+const noop = () => {}
+
+module.exports = class BodyReadable extends Readable {
+  constructor ({
+    resume,
+    abort,
+    contentType = '',
+    highWaterMark = 64 * 1024 // Same as nodejs fs streams.
+  }) {
+    super({
+      autoDestroy: true,
+      read: resume,
+      highWaterMark
+    })
+
+    this._readableState.dataEmitted = false
+
+    this[kAbort] = abort
+    this[kConsume] = null
+    this[kBody] = null
+    this[kContentType] = contentType
+
+    // Is stream being consumed through Readable API?
+    // This is an optimization so that we avoid checking
+    // for 'data' and 'readable' listeners in the hot path
+    // inside push().
+    this[kReading] = false
+  }
+
+  destroy (err) {
+    if (this.destroyed) {
+      // Node < 16
+      return this
+    }
+
+    if (!err && !this._readableState.endEmitted) {
+      err = new RequestAbortedError()
+    }
+
+    if (err) {
+      this[kAbort]()
+    }
+
+    return super.destroy(err)
+  }
+
+  emit (ev, ...args) {
+    if (ev === 'data') {
+      // Node < 16.7
+      this._readableState.dataEmitted = true
+    } else if (ev === 'error') {
+      // Node < 16
+      this._readableState.errorEmitted = true
+    }
+    return super.emit(ev, ...args)
+  }
+
+  on (ev, ...args) {
+    if (ev === 'data' || ev === 'readable') {
+      this[kReading] = true
+    }
+    return super.on(ev, ...args)
+  }
+
+  addListener (ev, ...args) {
+    return this.on(ev, ...args)
+  }
+
+  off (ev, ...args) {
+    const ret = super.off(ev, ...args)
+    if (ev === 'data' || ev === 'readable') {
+      this[kReading] = (
+        this.listenerCount('data') > 0 ||
+        this.listenerCount('readable') > 0
+      )
+    }
+    return ret
+  }
+
+  removeListener (ev, ...args) {
+    return this.off(ev, ...args)
+  }
+
+  push (chunk) {
+    if (this[kConsume] && chunk !== null && this.readableLength === 0) {
+      consumePush(this[kConsume], chunk)
+      return this[kReading] ? super.push(chunk) : true
+    }
+    return super.push(chunk)
+  }
+
+  // https://fetch.spec.whatwg.org/#dom-body-text
+  async text () {
+    return consume(this, 'text')
+  }
+
+  // https://fetch.spec.whatwg.org/#dom-body-json
+  async json () {
+    return consume(this, 'json')
+  }
+
+  // https://fetch.spec.whatwg.org/#dom-body-blob
+  async blob () {
+    return consume(this, 'blob')
+  }
+
+  // https://fetch.spec.whatwg.org/#dom-body-arraybuffer
+  async arrayBuffer () {
+    return consume(this, 'arrayBuffer')
+  }
+
+  // https://fetch.spec.whatwg.org/#dom-body-formdata
+  async formData () {
+    // TODO: Implement.
+    throw new NotSupportedError()
+  }
+
+  // https://fetch.spec.whatwg.org/#dom-body-bodyused
+  get bodyUsed () {
+    return util.isDisturbed(this)
+  }
+
+  // https://fetch.spec.whatwg.org/#dom-body-body
+  get body () {
+    if (!this[kBody]) {
+      this[kBody] = ReadableStreamFrom(this)
+      if (this[kConsume]) {
+        // TODO: Is this the best way to force a lock?
+        this[kBody].getReader() // Ensure stream is locked.
+        assert(this[kBody].locked)
+      }
+    }
+    return this[kBody]
+  }
+
+  dump (opts) {
+    let limit = opts && Number.isFinite(opts.limit) ? opts.limit : 262144
+    const signal = opts && opts.signal
+
+    if (signal) {
+      try {
+        if (typeof signal !== 'object' || !('aborted' in signal)) {
+          throw new InvalidArgumentError('signal must be an AbortSignal')
+        }
+        util.throwIfAborted(signal)
+      } catch (err) {
+        return Promise.reject(err)
+      }
+    }
+
+    if (this.closed) {
+      return Promise.resolve(null)
+    }
+
+    return new Promise((resolve, reject) => {
+      const signalListenerCleanup = signal
+        ? util.addAbortListener(signal, () => {
+          this.destroy()
+        })
+        : noop
+
+      this
+        .on('close', function () {
+          signalListenerCleanup()
+          if (signal && signal.aborted) {
+            reject(signal.reason || Object.assign(new Error('The operation was aborted'), { name: 'AbortError' }))
+          } else {
+            resolve(null)
+          }
+        })
+        .on('error', noop)
+        .on('data', function (chunk) {
+          limit -= chunk.length
+          if (limit <= 0) {
+            this.destroy()
+          }
+        })
+        .resume()
+    })
+  }
+}
+
+// https://streams.spec.whatwg.org/#readablestream-locked
+function isLocked (self) {
+  // Consume is an implicit lock.
+  return (self[kBody] && self[kBody].locked === true) || self[kConsume]
+}
+
+// https://fetch.spec.whatwg.org/#body-unusable
+function isUnusable (self) {
+  return util.isDisturbed(self) || isLocked(self)
+}
+
+async function consume (stream, type) {
+  if (isUnusable(stream)) {
+    throw new TypeError('unusable')
+  }
+
+  assert(!stream[kConsume])
+
+  return new Promise((resolve, reject) => {
+    stream[kConsume] = {
+      type,
+      stream,
+      resolve,
+      reject,
+      length: 0,
+      body: []
+    }
+
+    stream
+      .on('error', function (err) {
+        consumeFinish(this[kConsume], err)
+      })
+      .on('close', function () {
+        if (this[kConsume].body !== null) {
+          consumeFinish(this[kConsume], new RequestAbortedError())
+        }
+      })
+
+    process.nextTick(consumeStart, stream[kConsume])
+  })
+}
+
+function consumeStart (consume) {
+  if (consume.body === null) {
+    return
+  }
+
+  const { _readableState: state } = consume.stream
+
+  for (const chunk of state.buffer) {
+    consumePush(consume, chunk)
+  }
+
+  if (state.endEmitted) {
+    consumeEnd(this[kConsume])
+  } else {
+    consume.stream.on('end', function () {
+      consumeEnd(this[kConsume])
+    })
+  }
+
+  consume.stream.resume()
+
+  while (consume.stream.read() != null) {
+    // Loop
+  }
+}
+
+function consumeEnd (consume) {
+  const { type, body, resolve, stream, length } = consume
+
+  try {
+    if (type === 'text') {
+      resolve(toUSVString(Buffer.concat(body)))
+    } else if (type === 'json') {
+      resolve(JSON.parse(Buffer.concat(body)))
+    } else if (type === 'arrayBuffer') {
+      const dst = new Uint8Array(length)
+
+      let pos = 0
+      for (const buf of body) {
+        dst.set(buf, pos)
+        pos += buf.byteLength
+      }
+
+      resolve(dst.buffer)
+    } else if (type === 'blob') {
+      if (!Blob) {
+        Blob = require('buffer').Blob
+      }
+      resolve(new Blob(body, { type: stream[kContentType] }))
+    }
+
+    consumeFinish(consume)
+  } catch (err) {
+    stream.destroy(err)
+  }
+}
+
+function consumePush (consume, chunk) {
+  consume.length += chunk.length
+  consume.body.push(chunk)
+}
+
+function consumeFinish (consume, err) {
+  if (consume.body === null) {
+    return
+  }
+
+  if (err) {
+    consume.reject(err)
+  } else {
+    consume.resolve()
+  }
+
+  consume.type = null
+  consume.stream = null
+  consume.resolve = null
+  consume.reject = null
+  consume.length = 0
+  consume.body = null
+}