1 files changed, 308 insertions, 0 deletions
diff --git a/std/node/_stream/pipeline.ts b/std/node/_stream/pipeline.ts
new file mode 100644
index 000000000..d02a92870
--- /dev/null
+++ b/std/node/_stream/pipeline.ts
@@ -0,0 +1,308 @@
+// Copyright Node.js contributors. All rights reserved. MIT License.
+import { once } from "../_utils.ts";
+import { destroyer as implDestroyer } from "./destroy.ts";
+import eos from "./end_of_stream.ts";
+import createReadableStreamAsyncIterator from "./async_iterator.ts";
+import * as events from "../events.ts";
+import PassThrough from "./passthrough.ts";
+import {
+  ERR_INVALID_ARG_TYPE,
+  ERR_INVALID_CALLBACK,
+  ERR_INVALID_RETURN_VALUE,
+  ERR_MISSING_ARGS,
+  ERR_STREAM_DESTROYED,
+  NodeErrorAbstraction,
+} from "../_errors.ts";
+import type Duplex from "./duplex.ts";
+import type Readable from "./readable.ts";
+import type Stream from "./stream.ts";
+import type Transform from "./transform.ts";
+import type Writable from "./writable.ts";
+
+type Streams = Duplex | Readable | Writable;
+// deno-lint-ignore no-explicit-any
+type EndCallback = (err?: NodeErrorAbstraction | null, val?: any) => void;
+type TransformCallback =
+  // deno-lint-ignore no-explicit-any
+  | ((value?: any) => AsyncGenerator<any>)
+  // deno-lint-ignore no-explicit-any
+  | ((value?: any) => Promise<any>);
+/**
+ * This type represents an array that contains a data source,
+ * many Transform Streams, a writable stream destination
+ * and end in an optional callback
+ * */
+type DataSource =
+  // deno-lint-ignore no-explicit-any
+  | (() => AsyncGenerator<any>)
+  | // deno-lint-ignore no-explicit-any
+  AsyncIterable<any>
+  | Duplex
+  | // deno-lint-ignore no-explicit-any
+  Iterable<any>
+  | // deno-lint-ignore no-explicit-any
+  (() => Generator<any>)
+  | Readable;
+type Transformers = Duplex | Transform | TransformCallback | Writable;
+export type PipelineArguments = [
+  DataSource,
+  ...Array<Transformers | EndCallback>,
+];
+
+function destroyer(
+  stream: Streams,
+  reading: boolean,
+  writing: boolean,
+  callback: EndCallback,
+) {
+  callback = once(callback);
+
+  let finished = false;
+  stream.on("close", () => {
+    finished = true;
+  });
+
+  eos(stream, { readable: reading, writable: writing }, (err) => {
+    finished = !err;
+
+    // deno-lint-ignore no-explicit-any
+    const rState = (stream as any)?._readableState;
+    if (
+      err &&
+      err.code === "ERR_STREAM_PREMATURE_CLOSE" &&
+      reading &&
+      (rState?.ended && !rState?.errored && !rState?.errorEmitted)
+    ) {
+      stream
+        .once("end", callback)
+        .once("error", callback);
+    } else {
+      callback(err);
+    }
+  });
+
+  return (err: NodeErrorAbstraction) => {
+    if (finished) return;
+    finished = true;
+    implDestroyer(stream, err);
+    callback(err || new ERR_STREAM_DESTROYED("pipe"));
+  };
+}
+
+function popCallback(streams: PipelineArguments): EndCallback {
+  if (typeof streams[streams.length - 1] !== "function") {
+    throw new ERR_INVALID_CALLBACK(streams[streams.length - 1]);
+  }
+  return streams.pop() as EndCallback;
+}
+
+// function isPromise(obj) {
+//   return !!(obj && typeof obj.then === "function");
+// }
+
+// deno-lint-ignore no-explicit-any
+function isReadable(obj: any): obj is Stream {
+  return !!(obj && typeof obj.pipe === "function");
+}
+
+// deno-lint-ignore no-explicit-any
+function isWritable(obj: any) {
+  return !!(obj && typeof obj.write === "function");
+}
+
+// deno-lint-ignore no-explicit-any
+function isStream(obj: any) {
+  return isReadable(obj) || isWritable(obj);
+}
+
+// deno-lint-ignore no-explicit-any
+function isIterable(obj: any, isAsync?: boolean) {
+  if (!obj) return false;
+  if (isAsync === true) return typeof obj[Symbol.asyncIterator] === "function";
+  if (isAsync === false) return typeof obj[Symbol.iterator] === "function";
+  return typeof obj[Symbol.asyncIterator] === "function" ||
+    typeof obj[Symbol.iterator] === "function";
+}
+
+// deno-lint-ignore no-explicit-any
+function makeAsyncIterable(val: Readable | Iterable<any> | AsyncIterable<any>) {
+  if (isIterable(val)) {
+    return val;
+  } else if (isReadable(val)) {
+    return fromReadable(val as Readable);
+  }
+  throw new ERR_INVALID_ARG_TYPE(
+    "val",
+    ["Readable", "Iterable", "AsyncIterable"],
+    val,
+  );
+}
+
+async function* fromReadable(val: Readable) {
+  yield* createReadableStreamAsyncIterator(val);
+}
+
+async function pump(
+  // deno-lint-ignore no-explicit-any
+  iterable: Iterable<any>,
+  writable: Duplex | Writable,
+  finish: (err?: NodeErrorAbstraction | null) => void,
+) {
+  let error;
+  try {
+    for await (const chunk of iterable) {
+      if (!writable.write(chunk)) {
+        if (writable.destroyed) return;
+        await events.once(writable, "drain");
+      }
+    }
+    writable.end();
+  } catch (err) {
+    error = err;
+  } finally {
+    finish(error);
+  }
+}
+
+export default function pipeline(...args: PipelineArguments) {
+  const callback: EndCallback = once(popCallback(args));
+
+  let streams: [DataSource, ...Transformers[]];
+  if (args.length > 1) {
+    streams = args as [DataSource, ...Transformers[]];
+  } else {
+    throw new ERR_MISSING_ARGS("streams");
+  }
+
+  let error: NodeErrorAbstraction;
+  // deno-lint-ignore no-explicit-any
+  let value: any;
+  const destroys: Array<(err: NodeErrorAbstraction) => void> = [];
+
+  let finishCount = 0;
+
+  function finish(err?: NodeErrorAbstraction | null) {
+    const final = --finishCount === 0;
+
+    if (err && (!error || error.code === "ERR_STREAM_PREMATURE_CLOSE")) {
+      error = err;
+    }
+
+    if (!error && !final) {
+      return;
+    }
+
+    while (destroys.length) {
+      (destroys.shift() as (err: NodeErrorAbstraction) => void)(error);
+    }
+
+    if (final) {
+      callback(error, value);
+    }
+  }
+
+  // TODO(Soremwar)
+  // Simplify the hell out of this
+  // deno-lint-ignore no-explicit-any
+  let ret: any;
+  for (let i = 0; i < streams.length; i++) {
+    const stream = streams[i];
+    const reading = i < streams.length - 1;
+    const writing = i > 0;
+
+    if (isStream(stream)) {
+      finishCount++;
+      destroys.push(destroyer(stream as Streams, reading, writing, finish));
+    }
+
+    if (i === 0) {
+      if (typeof stream === "function") {
+        ret = stream();
+        if (!isIterable(ret)) {
+          throw new ERR_INVALID_RETURN_VALUE(
+            "Iterable, AsyncIterable or Stream",
+            "source",
+            ret,
+          );
+        }
+      } else if (isIterable(stream) || isReadable(stream)) {
+        ret = stream;
+      } else {
+        throw new ERR_INVALID_ARG_TYPE(
+          "source",
+          ["Stream", "Iterable", "AsyncIterable", "Function"],
+          stream,
+        );
+      }
+    } else if (typeof stream === "function") {
+      ret = makeAsyncIterable(ret);
+      ret = stream(ret);
+
+      if (reading) {
+        if (!isIterable(ret, true)) {
+          throw new ERR_INVALID_RETURN_VALUE(
+            "AsyncIterable",
+            `transform[${i - 1}]`,
+            ret,
+          );
+        }
+      } else {
+        // If the last argument to pipeline is not a stream
+        // we must create a proxy stream so that pipeline(...)
+        // always returns a stream which can be further
+        // composed through `.pipe(stream)`.
+        const pt = new PassThrough({
+          objectMode: true,
+        });
+        if (ret instanceof Promise) {
+          ret
+            .then((val) => {
+              value = val;
+              pt.end(val);
+            }, (err) => {
+              pt.destroy(err);
+            });
+        } else if (isIterable(ret, true)) {
+          finishCount++;
+          pump(ret, pt, finish);
+        } else {
+          throw new ERR_INVALID_RETURN_VALUE(
+            "AsyncIterable or Promise",
+            "destination",
+            ret,
+          );
+        }
+
+        ret = pt;
+
+        finishCount++;
+        destroys.push(destroyer(ret, false, true, finish));
+      }
+    } else if (isStream(stream)) {
+      if (isReadable(ret)) {
+        ret.pipe(stream as Readable);
+
+        // TODO(Soremwar)
+        // Reimplement after stdout and stderr are implemented
+        // if (stream === process.stdout || stream === process.stderr) {
+        //   ret.on("end", () => stream.end());
+        // }
+      } else {
+        ret = makeAsyncIterable(ret);
+
+        finishCount++;
+        pump(ret, stream as Writable, finish);
+      }
+      ret = stream;
+    } else {
+      const name = reading ? `transform[${i - 1}]` : "destination";
+      throw new ERR_INVALID_ARG_TYPE(
+        name,
+        ["Stream", "Function"],
+        ret,
+      );
+    }
+  }
+
+  return ret as unknown as Readable;
+}