http,stream: add writableEnded

This is work towards resolving the response.finished confusion and
future deprecation.

Note that implementation-wise, streams have both an ending and ended
state. However, in this case (in order to avoid confusion in user space)
writableEnded is equal to writable.ending. The ending vs ended situation
is internal state required for internal stream logic.

PR-URL: https://github.com/nodejs/node/pull/28934
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: Trivikram Kamat <trivikr.dev@gmail.com>
Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com>
Reviewed-By: Rich Trott <rtrott@gmail.com>

doc/api/http.md

@@ -764,6 +764,27 @@ req.once('response', (res) => {
 });
 ```
 
+### request.writableEnded
+<!-- YAML
+added: REPLACEME
+-->
+
+* {boolean}
+
+Is `true` after [`request.end()`][] has been called. This property
+does not indicate whether the data has been flushed, for this use
+[`request.writableFinished`][] instead.
+
+### request.writableFinished
+<!-- YAML
+added: v12.7.0
+-->
+
+* {boolean}
+
+Is `true` if all data has been flushed to the underlying system, immediately
+before the [`'finish'`][] event is emitted.
+
 ### request.write(chunk[, encoding][, callback])
 <!-- YAML
 added: v0.1.29
@@ -1436,6 +1457,17 @@ response.statusMessage = 'Not found';
 After response header was sent to the client, this property indicates the
 status message which was sent out.
 
+### response.writableEnded
+<!-- YAML
+added: REPLACEME
+-->
+
+* {boolean}
+
+Is `true` after [`response.end()`][] has been called. This property
+does not indicate whether the data has been flushed, for this use
+[`response.writableFinished`][] instead.
+
 ### response.writableFinished
 <!-- YAML
 added: v12.7.0
@@ -2222,11 +2254,13 @@ not abort the request or do anything besides add a `'timeout'` event.
 [`request.setTimeout()`]: #http_request_settimeout_timeout_callback
 [`request.socket.getPeerCertificate()`]: tls.html#tls_tlssocket_getpeercertificate_detailed
 [`request.socket`]: #http_request_socket
+[`request.writableFinished`]: #http_request_writablefinished
 [`request.write(data, encoding)`]: #http_request_write_chunk_encoding_callback
 [`response.end()`]: #http_response_end_data_encoding_callback
 [`response.getHeader()`]: #http_response_getheader_name
 [`response.setHeader()`]: #http_response_setheader_name_value
 [`response.socket`]: #http_response_socket
+[`response.writableFinished`]: #http_response_writablefinished
 [`response.write()`]: #http_response_write_chunk_encoding_callback
 [`response.write(data, encoding)`]: #http_response_write_chunk_encoding_callback
 [`response.writeContinue()`]: #http_response_writecontinue

doc/api/http2.md

@@ -3271,6 +3271,17 @@ added: v8.4.0
 
 The [`Http2Stream`][] object backing the response.
 
+#### response.writableEnded
+<!-- YAML
+added: REPLACEME
+-->
+
+* {boolean}
+
+Is `true` after [`response.end()`][] has been called. This property
+does not indicate whether the data has been flushed, for this use
+[`writable.writableFinished`][] instead.
+
 #### response.write(chunk[, encoding][, callback])
 <!-- YAML
 added: v8.4.0
@@ -3510,3 +3521,4 @@ following additional properties:
 [`tls.connect()`]: tls.html#tls_tls_connect_options_callback
 [`tls.createServer()`]: tls.html#tls_tls_createserver_options_secureconnectionlistener
 [error code]: #error_codes
+[`writable.writableFinished`]: stream.html#stream_writable_writablefinished

doc/api/stream.md

@@ -494,6 +494,17 @@ added: v11.4.0
 
 Is `true` if it is safe to call [`writable.write()`][stream-write].
 
+##### writable.writableEnded
+<!-- YAML
+added: REPLACEME
+-->
+
+* {boolean}
+
+Is `true` after [`writable.end()`][] has been called. This property
+does not indicate whether the data has been flushed, for this use
+[`writable.writableFinished`][] instead.
+
 ##### writable.writableFinished
 <!-- YAML
 added: v12.6.0
@@ -2707,7 +2718,9 @@ contain multi-byte characters.
 [`stream.unpipe()`]: #stream_readable_unpipe_destination
 [`stream.wrap()`]: #stream_readable_wrap_stream
 [`writable.cork()`]: #stream_writable_cork
+[`writable.end()`]: #stream_writable_end_chunk_encoding_callback
 [`writable.uncork()`]: #stream_writable_uncork
+[`writable.writableFinished`]: #stream_writable_writablefinished
 [`zlib.createDeflate()`]: zlib.html#zlib_zlib_createdeflate_options
 [API for Stream Consumers]: #stream_api_for_stream_consumers
 [API for Stream Implementers]: #stream_api_for_stream_implementers

lib/_http_outgoing.js

@@ -575,6 +575,10 @@ Object.defineProperty(OutgoingMessage.prototype, 'headersSent', {
   get: function() { return !!this._header; }
 });
 
+Object.defineProperty(OutgoingMessage.prototype, 'writableEnded', {
+  get: function() { return this.finished; }
+});
+
 
 const crlf_buf = Buffer.from('\r\n');
 OutgoingMessage.prototype.write = function write(chunk, encoding, callback) {

lib/_stream_duplex.js

@@ -74,7 +74,7 @@ Object.defineProperty(Duplex.prototype, 'writableHighWaterMark', {
   // userland will fail
   enumerable: false,
   get() {
-    return this._writableState.highWaterMark;
+    return this._writableState && this._writableState.highWaterMark;
   }
 });
 
@@ -94,7 +94,7 @@ Object.defineProperty(Duplex.prototype, 'writableLength', {
   // userland will fail
   enumerable: false,
   get() {
-    return this._writableState.length;
+    return this._writableState && this._writableState.length;
   }
 });
 
@@ -104,7 +104,17 @@ Object.defineProperty(Duplex.prototype, 'writableFinished', {
   // userland will fail
   enumerable: false,
   get() {
-    return this._writableState.finished;
+    return this._writableState ? this._writableState.finished : false;
+  }
+});
+
+Object.defineProperty(Duplex.prototype, 'writableEnded', {
+  // Making it explicit this property is not enumerable
+  // because otherwise some prototype manipulation in
+  // userland will fail
+  enumerable: false,
+  get() {
+    return this._writableState ? this._writableState.ending : false;
   }
 });
 

lib/_stream_writable.js

@@ -352,13 +352,23 @@ function decodeChunk(state, chunk, encoding) {
   return chunk;
 }
 
+Object.defineProperty(Writable.prototype, 'writableEnded', {
+  // Making it explicit this property is not enumerable
+  // because otherwise some prototype manipulation in
+  // userland will fail
+  enumerable: false,
+  get: function() {
+    return this._writableState ? this._writableState.ending : false;
+  }
+});
+
 Object.defineProperty(Writable.prototype, 'writableHighWaterMark', {
   // Making it explicit this property is not enumerable
   // because otherwise some prototype manipulation in
   // userland will fail
   enumerable: false,
   get: function() {
-    return this._writableState.highWaterMark;
+    return this._writableState && this._writableState.highWaterMark;
   }
 });
 
@@ -711,7 +721,7 @@ Object.defineProperty(Writable.prototype, 'writableFinished', {
   // userland will fail
   enumerable: false,
   get() {
-    return this._writableState.finished;
+    return this._writableState ? this._writableState.finished : false;
   }
 });
 

lib/internal/http2/compat.js

@@ -454,6 +454,11 @@ class Http2ServerResponse extends Stream {
     return this.headersSent;
   }
 
+  get writableEnded() {
+    const state = this[kState];
+    return state.ending;
+  }
+
   get finished() {
     const stream = this[kStream];
     return stream.destroyed ||

test/parallel/test-http-outgoing-finish-writable.js

@@ -9,12 +9,14 @@ const http = require('http');
 const server = http.createServer(common.mustCall(function(req, res) {
   assert.strictEqual(res.writable, true);
   assert.strictEqual(res.finished, false);
+  assert.strictEqual(res.writableEnded, false);
   res.end();
 
   // res.writable is set to false after it has finished sending
   // Ref: https://github.com/nodejs/node/issues/15029
   assert.strictEqual(res.writable, true);
   assert.strictEqual(res.finished, true);
+  assert.strictEqual(res.writableEnded, true);
 
   server.close();
 }));

test/parallel/test-http2-compat-serverresponse-end.js

@@ -150,8 +150,10 @@ const {
   // for http1 compatibility
   const server = createServer(mustCall((request, response) => {
     strictEqual(response.finished, true);
+    strictEqual(response.writableEnded, false);
     response.writeHead(HTTP_STATUS_OK, { foo: 'bar' });
     response.end('data', mustCall());
+    strictEqual(response.writableEnded, true);
   }));
   server.listen(0, mustCall(() => {
     const { port } = server.address();

test/parallel/test-http2-compat-serverresponse-finished.js

@@ -25,8 +25,10 @@ server.listen(0, common.mustCall(() => {
       }));
     }));
     assert.strictEqual(response.finished, false);
+    assert.strictEqual(response.writableEnded, false);
     response.end();
     assert.strictEqual(response.finished, true);
+    assert.strictEqual(response.writableEnded, true);
   }));
 
   const url = `http://localhost:${port}`;

test/parallel/test-stream-writable-ended-state.js

@@ -9,13 +9,17 @@ const writable = new stream.Writable();
 
 writable._write = (chunk, encoding, cb) => {
   assert.strictEqual(writable._writableState.ended, false);
+  assert.strictEqual(writable.writableEnded, false);
   cb();
 };
 
 assert.strictEqual(writable._writableState.ended, false);
+assert.strictEqual(writable.writableEnded, false);
 
 writable.end('testing ended state', common.mustCall(() => {
   assert.strictEqual(writable._writableState.ended, true);
+  assert.strictEqual(writable.writableEnded, true);
 }));
 
 assert.strictEqual(writable._writableState.ended, true);
+assert.strictEqual(writable.writableEnded, true);