stream: enable usage of webstreams on compose()

Refs: nodejs#39316

lib/internal/streams/compose.js

@@ -7,6 +7,10 @@ const {
   isNodeStream,
   isReadable,
   isWritable,
+  isWebStream,
+  isTransformStream,
+  isWritableStream,
+  isReadableStream,
 } = require('internal/streams/utils');
 const {
   AbortError,
@@ -15,6 +19,7 @@ const {
     ERR_MISSING_ARGS,
   },
 } = require('internal/errors');
+const eos = require('internal/streams/end-of-stream');
 
 module.exports = function compose(...streams) {
   if (streams.length === 0) {
@@ -57,9 +62,8 @@ module.exports = function compose(...streams) {
     }
   }
 
-  let ondrain;
-  let onfinish;
-  let onreadable;
+  let writableEndDestructor;
+  let readableEndDestructor;
   let onclose;
   let d;
 
@@ -79,8 +83,8 @@ module.exports = function compose(...streams) {
   const head = streams[0];
   const tail = pipeline(streams, onfinished);
 
-  const writable = !!isWritable(head);
-  const readable = !!isReadable(tail);
+  const writable = !!(isWritable(head) || isWritableStream(head) || isTransformStream(head));
+  const readable = !!(isReadable(tail) || isReadableStream(tail) || isTransformStream(tail));
 
   // TODO(ronag): Avoid double buffering.
   // Implement Writable/Readable/Duplex traits.
@@ -94,15 +98,51 @@ module.exports = function compose(...streams) {
   });
 
   if (writable) {
-    d._write = function(chunk, encoding, callback) {
+    writableEndDestructor = makeWritableEnd(d, head, tail);
+  }
+
+  if (readable) {
+    readableEndDestructor = makeReadableEnd(d, head, tail);
+  }
+
+  d._destroy = function(err, callback) {
+    if (!err && onclose !== null) {
+      err = new AbortError();
+    }
+
+    if (readableEndDestructor) {
+      readableEndDestructor();
+    }
+
+    if (writableEndDestructor) {
+      writableEndDestructor();
+    }
+
+    if (onclose === null) {
+      callback(err);
+    } else {
+      onclose = callback;
+      destroyer(tail, err);
+    }
+  };
+
+  return d;
+};
+
+function makeWritableEnd(duplex, head, tail) {
+  let ondrain;
+  let onfinish;
+
+  if (isNodeStream(head)) {
+    duplex._write = function(chunk, encoding, callback) {
       if (head.write(chunk, encoding)) {
         callback();
       } else {
         ondrain = callback;
       }
     };
 
-    d._final = function(callback) {
+    duplex._final = function(callback) {
       head.end();
       onfinish = callback;
     };
@@ -114,17 +154,61 @@ module.exports = function compose(...streams) {
         cb();
       }
     });
+  } else if (isWebStream(head)) {
+    const writable = isTransformStream(head) ? head.writable : head;
+    const writer = writable.getWriter();
+
+    duplex._write = async function(chunk, encoding, callback) {
+      try {
+        await writer.ready;
+        writer.write(chunk).catch(() => {});
+        callback();
+      } catch (err) {
+        callback(err);
+      }
+    };
 
+    duplex._final = async function(callback) {
+      try {
+        await writer.ready;
+        writer.close();
+        onfinish = callback;
+      } catch (err) {
+        callback(err);
+      }
+    };
+  }
+
+  if (isNodeStream(tail)) {
     tail.on('finish', function() {
       if (onfinish) {
         const cb = onfinish;
         onfinish = null;
         cb();
       }
     });
+  } else if (isWebStream(tail)) {
+    const readable = isTransformStream(tail) ? tail.readable : tail;
+    eos(readable, () => {
+      if (onfinish) {
+        const cb = onfinish;
+        onfinish = null;
+        cb();
+      }
+    });
   }
 
-  if (readable) {
+  function destructor() {
+    ondrain = null;
+    onfinish = null;
+  }
+
+  return destructor;
+}
+
+function makeReadableEnd(duplex, head, tail) {
+  let onreadable;
+  if (isNodeStream(tail)) {
     tail.on('readable', function() {
       if (onreadable) {
         const cb = onreadable;
@@ -134,41 +218,43 @@ module.exports = function compose(...streams) {
     });
 
     tail.on('end', function() {
-      d.push(null);
+      duplex.push(null);
     });
 
-    d._read = function() {
+    duplex._read = function() {
       while (true) {
         const buf = tail.read();
-
         if (buf === null) {
-          onreadable = d._read;
+          onreadable = duplex._read;
           return;
         }
 
-        if (!d.push(buf)) {
+        if (!duplex.push(buf)) {
           return;
         }
       }
     };
-  }
+  } else if (isWebStream(tail)) {
+    const readable = isTransformStream(tail) ? tail.readable : tail;
+    const reader = readable.getReader();
+    duplex._read = async function() {
+      while (true) {
+        const { value, done } = await reader.read();
+        if (done) {
+          duplex.push(null);
+          return;
+        }
 
-  d._destroy = function(err, callback) {
-    if (!err && onclose !== null) {
-      err = new AbortError();
-    }
+        if (!duplex.push(value)) {
+          return;
+        }
+      }
+    };
+  }
 
+  function destructor() {
     onreadable = null;
-    ondrain = null;
-    onfinish = null;
-
-    if (onclose === null) {
-      callback(err);
-    } else {
-      onclose = callback;
-      destroyer(tail, err);
-    }
-  };
+  }
 
-  return d;
-};
+  return destructor;
+}

lib/internal/streams/pipeline.js

@@ -285,7 +285,7 @@ function pipelineImpl(streams, callback, opts) {
           throw new ERR_INVALID_RETURN_VALUE(
             'Iterable, AsyncIterable or Stream', 'source', ret);
         }
-      } else if (isIterable(stream) || isReadableNodeStream(stream)) {
+      } else if (isIterable(stream) || isReadableNodeStream(stream) || isTransformStream(stream)) {
         ret = stream;
       } else {
         ret = Duplex.from(stream);