1 files changed, 249 insertions, 0 deletions
diff --git a/lib/api/api-pipeline.js b/lib/api/api-pipeline.js
new file mode 100644
index 0000000..af4a180
--- /dev/null
+++ b/lib/api/api-pipeline.js
@@ -0,0 +1,249 @@
+'use strict'
+
+const {
+  Readable,
+  Duplex,
+  PassThrough
+} = require('stream')
+const {
+  InvalidArgumentError,
+  InvalidReturnValueError,
+  RequestAbortedError
+} = require('../core/errors')
+const util = require('../core/util')
+const { AsyncResource } = require('async_hooks')
+const { addSignal, removeSignal } = require('./abort-signal')
+const assert = require('assert')
+
+const kResume = Symbol('resume')
+
+class PipelineRequest extends Readable {
+  constructor () {
+    super({ autoDestroy: true })
+
+    this[kResume] = null
+  }
+
+  _read () {
+    const { [kResume]: resume } = this
+
+    if (resume) {
+      this[kResume] = null
+      resume()
+    }
+  }
+
+  _destroy (err, callback) {
+    this._read()
+
+    callback(err)
+  }
+}
+
+class PipelineResponse extends Readable {
+  constructor (resume) {
+    super({ autoDestroy: true })
+    this[kResume] = resume
+  }
+
+  _read () {
+    this[kResume]()
+  }
+
+  _destroy (err, callback) {
+    if (!err && !this._readableState.endEmitted) {
+      err = new RequestAbortedError()
+    }
+
+    callback(err)
+  }
+}
+
+class PipelineHandler extends AsyncResource {
+  constructor (opts, handler) {
+    if (!opts || typeof opts !== 'object') {
+      throw new InvalidArgumentError('invalid opts')
+    }
+
+    if (typeof handler !== 'function') {
+      throw new InvalidArgumentError('invalid handler')
+    }
+
+    const { signal, method, opaque, onInfo, responseHeaders } = opts
+
+    if (signal && typeof signal.on !== 'function' && typeof signal.addEventListener !== 'function') {
+      throw new InvalidArgumentError('signal must be an EventEmitter or EventTarget')
+    }
+
+    if (method === 'CONNECT') {
+      throw new InvalidArgumentError('invalid method')
+    }
+
+    if (onInfo && typeof onInfo !== 'function') {
+      throw new InvalidArgumentError('invalid onInfo callback')
+    }
+
+    super('UNDICI_PIPELINE')
+
+    this.opaque = opaque || null
+    this.responseHeaders = responseHeaders || null
+    this.handler = handler
+    this.abort = null
+    this.context = null
+    this.onInfo = onInfo || null
+
+    this.req = new PipelineRequest().on('error', util.nop)
+
+    this.ret = new Duplex({
+      readableObjectMode: opts.objectMode,
+      autoDestroy: true,
+      read: () => {
+        const { body } = this
+
+        if (body && body.resume) {
+          body.resume()
+        }
+      },
+      write: (chunk, encoding, callback) => {
+        const { req } = this
+
+        if (req.push(chunk, encoding) || req._readableState.destroyed) {
+          callback()
+        } else {
+          req[kResume] = callback
+        }
+      },
+      destroy: (err, callback) => {
+        const { body, req, res, ret, abort } = this
+
+        if (!err && !ret._readableState.endEmitted) {
+          err = new RequestAbortedError()
+        }
+
+        if (abort && err) {
+          abort()
+        }
+
+        util.destroy(body, err)
+        util.destroy(req, err)
+        util.destroy(res, err)
+
+        removeSignal(this)
+
+        callback(err)
+      }
+    }).on('prefinish', () => {
+      const { req } = this
+
+      // Node < 15 does not call _final in same tick.
+      req.push(null)
+    })
+
+    this.res = null
+
+    addSignal(this, signal)
+  }
+
+  onConnect (abort, context) {
+    const { ret, res } = this
+
+    assert(!res, 'pipeline cannot be retried')
+
+    if (ret.destroyed) {
+      throw new RequestAbortedError()
+    }
+
+    this.abort = abort
+    this.context = context
+  }
+
+  onHeaders (statusCode, rawHeaders, resume) {
+    const { opaque, handler, context } = this
+
+    if (statusCode < 200) {
+      if (this.onInfo) {
+        const headers = this.responseHeaders === 'raw' ? util.parseRawHeaders(rawHeaders) : util.parseHeaders(rawHeaders)
+        this.onInfo({ statusCode, headers })
+      }
+      return
+    }
+
+    this.res = new PipelineResponse(resume)
+
+    let body
+    try {
+      this.handler = null
+      const headers = this.responseHeaders === 'raw' ? util.parseRawHeaders(rawHeaders) : util.parseHeaders(rawHeaders)
+      body = this.runInAsyncScope(handler, null, {
+        statusCode,
+        headers,
+        opaque,
+        body: this.res,
+        context
+      })
+    } catch (err) {
+      this.res.on('error', util.nop)
+      throw err
+    }
+
+    if (!body || typeof body.on !== 'function') {
+      throw new InvalidReturnValueError('expected Readable')
+    }
+
+    body
+      .on('data', (chunk) => {
+        const { ret, body } = this
+
+        if (!ret.push(chunk) && body.pause) {
+          body.pause()
+        }
+      })
+      .on('error', (err) => {
+        const { ret } = this
+
+        util.destroy(ret, err)
+      })
+      .on('end', () => {
+        const { ret } = this
+
+        ret.push(null)
+      })
+      .on('close', () => {
+        const { ret } = this
+
+        if (!ret._readableState.ended) {
+          util.destroy(ret, new RequestAbortedError())
+        }
+      })
+
+    this.body = body
+  }
+
+  onData (chunk) {
+    const { res } = this
+    return res.push(chunk)
+  }
+
+  onComplete (trailers) {
+    const { res } = this
+    res.push(null)
+  }
+
+  onError (err) {
+    const { ret } = this
+    this.handler = null
+    util.destroy(ret, err)
+  }
+}
+
+function pipeline (opts, handler) {
+  try {
+    const pipelineHandler = new PipelineHandler(opts, handler)
+    this.dispatch({ ...opts, body: pipelineHandler.req }, pipelineHandler)
+    return pipelineHandler.ret
+  } catch (err) {
+    return new PassThrough().destroy(err)
+  }
+}
+
+module.exports = pipeline