From 53b12f0c7bf0df695c9640adccead3c9142552d5 Mon Sep 17 00:00:00 2001
From: James M Snell <jasnell@gmail.com>
Date: Thu, 9 Jul 2020 16:31:41 -0700
Subject: [PATCH] quic: implement QuicEndpoint Promise API

This is the start of a conversion over to a fully Promise-centric API
for the QUIC implementation.

PR-URL: https://github.com/nodejs/node/pull/34283
Reviewed-By: Anna Henningsen <anna@addaleax.net>
---
 doc/api/quic.md                               |  42 +++++
 lib/internal/quic/core.js                     | 160 ++++++++++++++++--
 .../test-quic-quicendpoint-address.js         |  18 +-
 3 files changed, 200 insertions(+), 20 deletions(-)

diff --git a/doc/api/quic.md b/doc/api/quic.md
index 46f521789ef799..dee7f65f55cd49 100644
--- a/doc/api/quic.md
+++ b/doc/api/quic.md
@@ -338,6 +338,34 @@ The object will contain the properties:
 
 If the `QuicEndpoint` is not bound, `quicendpoint.address` is an empty object.
 
+#### quicendpoint.bind(\[options\])
+<!-- YAML
+  added: REPLACEME
+-->
+
+Binds the `QuicEndpoint` if it has not already been bound. User code will
+not typically be responsible for binding a `QuicEndpoint` as the owning
+`QuicSocket` will do that automatically.
+
+* `options` {object}
+  * `signal` {AbortSignal} Optionally allows the `bind()` to be canceled
+    using an `AbortController`.
+* Returns: {Promise}
+
+The `quicendpoint.bind()` function returns `Promise` that will be resolved
+with the address once the bind operation is successful.
+
+If the `QuicEndpoint` has been destroyed, or is destroyed while the `Promise`
+is pending, the `Promise` will be rejected with an `ERR_INVALID_STATE` error.
+
+If an `AbortSignal` is specified in the `options` and it is triggered while
+the `Promise` is pending, the `Promise` will be rejected with an `AbortError`.
+
+If `quicendpoint.bind()` is called again while a previously returned `Promise`
+is still pending or has already successfully resolved, the previously returned
+pending `Promise` will be returned. If the additional call to
+`quicendpoint.bind()` contains an `AbortSignal`, the `signal` will be ignored.
+
 #### quicendpoint.bound
 <!-- YAML
 added: REPLACEME
@@ -347,6 +375,20 @@ added: REPLACEME
 
 Set to `true` if the `QuicEndpoint` is bound to the local UDP port.
 
+#### quicendpoint.close()
+<!-- YAML
+added: REPLACEME
+-->
+
+Closes and destroys the `QuicEndpoint`. Returns a `Promise` that is resolved
+once the `QuicEndpoint` has been destroyed, or rejects if the `QuicEndpoint`
+is destroyed with an error.
+
+* Returns: {Promise}
+
+The `Promise` cannot be canceled. Once `quicendpoint.close()` is called, the
+`QuicEndpoint` will be destroyed.
+
 #### quicendpoint.closing
 <!-- YAML
 added: REPLACEME
diff --git a/lib/internal/quic/core.js b/lib/internal/quic/core.js
index 65a204decc3e53..ab979ec8b920c9 100644
--- a/lib/internal/quic/core.js
+++ b/lib/internal/quic/core.js
@@ -16,6 +16,7 @@ const {
   Error,
   Map,
   Number,
+  Promise,
   RegExp,
   Set,
   Symbol,
@@ -104,6 +105,7 @@ const {
     ERR_QUICSESSION_VERSION_NEGOTIATION,
     ERR_TLS_DH_PARAM_SIZE,
   },
+  hideStackFrames,
   errnoException,
   exceptionWithHostPort
 } = require('internal/errors');
@@ -200,10 +202,14 @@ const {
 
 const emit = EventEmitter.prototype.emit;
 
+// TODO(@jasnell): Temporary while converting to Promises-based API
+const { lookup } = require('dns').promises;
+
 const kAfterLookup = Symbol('kAfterLookup');
 const kAfterPreferredAddressLookup = Symbol('kAfterPreferredAddressLookup');
 const kAddSession = Symbol('kAddSession');
 const kAddStream = Symbol('kAddStream');
+const kBind = Symbol('kBind');
 const kClose = Symbol('kClose');
 const kCert = Symbol('kCert');
 const kClientHello = Symbol('kClientHello');
@@ -255,6 +261,14 @@ const kSocketDestroyed = 4;
 let diagnosticPacketLossWarned = false;
 let warnedVerifyHostnameIdentity = false;
 
+let DOMException;
+
+const lazyDOMException = hideStackFrames((message) => {
+  if (DOMException === undefined)
+    DOMException = internalBinding('messaging').DOMException;
+  return new DOMException(message);
+});
+
 assert(process.versions.ngtcp2 !== undefined);
 
 // Called by the C++ internals when the QuicSocket is closed with
@@ -589,12 +603,27 @@ function lookupOrDefault(lookup, type) {
   return lookup || (type === AF_INET6 ? lookup6 : lookup4);
 }
 
+function deferredClosePromise(state) {
+  return state.closePromise = new Promise((resolve, reject) => {
+    state.closePromiseResolve = resolve;
+    state.closePromiseReject = reject;
+  }).finally(() => {
+    state.closePromise = undefined;
+    state.closePromiseResolve = undefined;
+    state.closePromiseReject = undefined;
+  });
+}
+
 // QuicEndpoint wraps a UDP socket and is owned
 // by a QuicSocket. It does not exist independently
 // of the QuicSocket.
 class QuicEndpoint {
   [kInternalState] = {
     state: kSocketUnbound,
+    bindPromise: undefined,
+    closePromise: undefined,
+    closePromiseResolve: undefined,
+    closePromiseReject: undefined,
     socket: undefined,
     udpSocket: undefined,
     address: undefined,
@@ -645,15 +674,14 @@ class QuicEndpoint {
     return customInspect(this, {
       address: this.address,
       fd: this.fd,
-      type: this[kInternalState].type === AF_INET6 ? 'udp6' : 'udp4'
+      type: this[kInternalState].type === AF_INET6 ? 'udp6' : 'udp4',
+      destroyed: this.destroyed,
+      bound: this.bound,
+      pending: this.pending,
     }, depth, options);
   }
 
-  // afterLookup is invoked when binding a QuicEndpoint. The first
-  // step to binding is to resolve the given hostname into an ip
-  // address. Once resolution is complete, the ip address needs to
-  // be passed on to the [kContinueBind] function or the QuicEndpoint
-  // needs to be destroyed.
+  // TODO(@jasnell): Remove once migration to Promise API is complete
   static [kAfterLookup](err, ip) {
     if (err) {
       this.destroy(err);
@@ -662,10 +690,7 @@ class QuicEndpoint {
     this[kContinueBind](ip);
   }
 
-  // kMaybeBind binds the endpoint on-demand if it is not already
-  // bound. If it is bound, we return immediately, otherwise put
-  // the endpoint into the pending state and initiate the binding
-  // process by calling the lookup to resolve the IP address.
+  // TODO(@jasnell): Remove once migration to Promise API is complete
   [kMaybeBind]() {
     const state = this[kInternalState];
     if (state.state !== kSocketUnbound)
@@ -674,8 +699,7 @@ class QuicEndpoint {
     state.lookup(state.address, QuicEndpoint[kAfterLookup].bind(this));
   }
 
-  // IP address resolution is completed and we're ready to finish
-  // binding to the local port.
+  // TODO(@jasnell): Remove once migration to Promise API is complete
   [kContinueBind](ip) {
     const state = this[kInternalState];
     const udpHandle = state.udpSocket[internalDgram.kStateSymbol].handle;
@@ -704,6 +728,95 @@ class QuicEndpoint {
     state.socket[kEndpointBound](this);
   }
 
+  bind(options) {
+    const state = this[kInternalState];
+    if (state.bindPromise !== undefined)
+      return state.bindPromise;
+
+    return state.bindPromise = this[kBind]().finally(() => {
+      state.bindPromise = undefined;
+    });
+  }
+
+  // Binds the QuicEndpoint to the local port. Returns a Promise
+  // that is resolved once the QuicEndpoint binds, or rejects if
+  // binding was not successful. Calling bind() multiple times
+  // before the Promise is resolved will return the same Promise.
+  // Calling bind() after the endpoint is already bound will
+  // immediately return a resolved promise. Calling bind() after
+  // the endpoint has been destroyed will cause the Promise to
+  // be rejected.
+  async [kBind](options) {
+    const state = this[kInternalState];
+    if (this.destroyed)
+      throw new ERR_INVALID_STATE('QuicEndpoint is already destroyed');
+
+    if (state.state !== kSocketUnbound)
+      return this.address;
+
+    const { signal } = { ...options };
+    if (signal != null && !('aborted' in signal))
+      throw new ERR_INVALID_ARG_TYPE('options.signal', 'AbortSignal', signal);
+
+    // If an AbotSignal was passed in, check to make sure it is not already
+    // aborted before we continue on to do any work.
+    if (signal && signal.aborted)
+      throw new lazyDOMException('AbortError');
+
+    state.state = kSocketPending;
+
+    // TODO(@jasnell): Use passed in lookup function once everything
+    // has been converted to Promises-based API
+    const {
+      address: ip
+    } = await lookup(state.address, state.type === AF_INET6 ? 6 : 4);
+
+    // It's possible for the QuicEndpoint to have been destroyed while
+    // we were waiting for the DNS lookup to complete. If so, reject
+    // the Promise.
+    if (this.destroyed)
+      throw new ERR_INVALID_STATE('QuicEndpoint was destroyed');
+
+    // If an AbortSignal was passed in, check to see if it was triggered
+    // while we were waiting.
+    if (signal && signal.aborted) {
+      state.state = kSocketUnbound;
+      throw new lazyDOMException('AbortError');
+    }
+
+    // From here on, any errors are fatal for the QuicEndpoint. Keep in
+    // mind that this means that the Bind Promise will be rejected *and*
+    // the QuicEndpoint will be destroyed with an error.
+    try {
+      const udpHandle = state.udpSocket[internalDgram.kStateSymbol].handle;
+      if (udpHandle == null) {
+        // It's not clear what cases trigger this but it is possible.
+        throw new ERR_OPERATION_FAILED('Acquiring UDP socket handle failed');
+      }
+
+      const flags =
+        (state.reuseAddr ? UV_UDP_REUSEADDR : 0) |
+        (state.ipv6Only ? UV_UDP_IPV6ONLY : 0);
+
+      const ret = udpHandle.bind(ip, state.port, flags);
+      if (ret)
+        throw exceptionWithHostPort(ret, 'bind', ip, state.port);
+
+      // On Windows, the fd will be meaningless, but we always record it.
+      state.fd = udpHandle.fd;
+      state.state = kSocketBound;
+
+      // Notify the owning socket that the QuicEndpoint has been successfully
+      // bound to the local UDP port.
+      state.socket[kEndpointBound](this);
+
+      return this.address;
+    } catch (error) {
+      this.destroy(error);
+      throw error;
+    }
+  }
+
   destroy(error) {
     if (this.destroyed)
       return;
@@ -727,12 +840,35 @@ class QuicEndpoint {
     handle.ondone = () => {
       state.udpSocket.close((err) => {
         if (err) error = err;
+        if (error && typeof state.closePromiseReject === 'function')
+          state.closePromiseReject(error);
+        else if (typeof state.closePromiseResolve === 'function')
+          state.closePromiseResolve();
         state.socket[kEndpointClose](this, error);
       });
     };
     handle.waitForPendingCallbacks();
   }
 
+  // Closes the QuicEndpoint. Returns a Promise that is resolved
+  // once the QuicEndpoint closes, or rejects if it closes with
+  // an error. Calling close() multiple times before the Promise
+  // is resolved will return the same Promise. Calling close()
+  // after will return a rejected Promise.
+  close() {
+    return this[kInternalState].closePromise || this[kClose]();
+  }
+
+  [kClose]() {
+    if (this.destroyed) {
+      return Promise.reject(
+        new ERR_INVALID_STATE('QuicEndpoint is already destroyed'));
+    }
+    const promise = deferredClosePromise(this[kInternalState]);
+    this.destroy();
+    return promise;
+  }
+
   // If the QuicEndpoint is bound, returns an object detailing
   // the local IP address, port, and address type to which it
   // is bound. Otherwise, returns an empty object.
diff --git a/test/parallel/test-quic-quicendpoint-address.js b/test/parallel/test-quic-quicendpoint-address.js
index 3a3c2c04831b27..742ecfbb71ed4b 100644
--- a/test/parallel/test-quic-quicendpoint-address.js
+++ b/test/parallel/test-quic-quicendpoint-address.js
@@ -16,20 +16,22 @@ const { createQuicSocket } = require('net');
 
 async function Test1(options, address) {
   const server = createQuicSocket(options);
-  assert.strictEqual(server.endpoints.length, 1);
-  assert.strictEqual(server.endpoints[0].bound, false);
-  assert.deepStrictEqual({}, server.endpoints[0].address);
-
-  server.listen({ key, cert, ca, alpn: 'zzz' });
+  server.on('close', common.mustCall());
 
-  await once(server, 'ready');
-  assert.strictEqual(server.endpoints.length, 1);
   const endpoint = server.endpoints[0];
+
+  assert.strictEqual(endpoint.bound, false);
+  assert.deepStrictEqual({}, endpoint.address);
+
+  await endpoint.bind();
+
   assert.strictEqual(endpoint.bound, true);
   assert.strictEqual(endpoint.destroyed, false);
   assert.strictEqual(typeof endpoint.address.port, 'number');
   assert.strictEqual(endpoint.address.address, address);
-  server.close();
+
+  await endpoint.close();
+
   assert.strictEqual(endpoint.destroyed, true);
 }