From c91258e8b634955e5b9f50c52229e44b715c6e03 Mon Sep 17 00:00:00 2001
From: "Jeremy W. Sherman" <jeremyw.sherman@gmail.com>
Date: Sun, 1 Aug 2021 21:10:11 -0400
Subject: [PATCH] feat: parse UTF-8 support FeatureExtAck

[#1143]
---
 src/token/feature-ext-ack-parser.ts        | 14 +++++++---
 src/token/token.ts                         |  8 +++++-
 test/unit/token/feature-ext-parser-test.js | 30 +++++++++++++++++++---
 3 files changed, 43 insertions(+), 9 deletions(-)

diff --git a/src/token/feature-ext-ack-parser.ts b/src/token/feature-ext-ack-parser.ts
index 62c727925..20971bb72 100644
--- a/src/token/feature-ext-ack-parser.ts
+++ b/src/token/feature-ext-ack-parser.ts
@@ -9,24 +9,30 @@ const FEATURE_ID = {
   COLUMNENCRYPTION: 0x04,
   GLOBALTRANSACTIONS: 0x05,
   AZURESQLSUPPORT: 0x08,
+  UTF8_SUPPORT: 0x0A,
   TERMINATOR: 0xFF
 };
 
 function featureExtAckParser(parser: Parser, _options: InternalConnectionOptions, callback: (token: FeatureExtAckToken) => void) {
   let fedAuth: Buffer | undefined;
+  let utf8Support: boolean | undefined;
 
   function next() {
     parser.readUInt8((featureId) => {
       if (featureId === FEATURE_ID.TERMINATOR) {
-        return callback(new FeatureExtAckToken(fedAuth));
+        return callback(new FeatureExtAckToken(fedAuth, utf8Support));
       }
 
       parser.readUInt32LE((featureAckDataLen) => {
         parser.readBuffer(featureAckDataLen, (featureData) => {
-          if (featureId === FEATURE_ID.FEDAUTH) {
-            fedAuth = featureData;
+          switch (featureId) {
+            case FEATURE_ID.FEDAUTH:
+              fedAuth = featureData;
+              break;
+            case FEATURE_ID.UTF8_SUPPORT:
+              utf8Support = !!featureData[0];
+              break;
           }
-
           next();
         });
       });
diff --git a/src/token/token.ts b/src/token/token.ts
index c785305d8..c5945adf5 100644
--- a/src/token/token.ts
+++ b/src/token/token.ts
@@ -316,10 +316,16 @@ export class FeatureExtAckToken extends Token {
 
   fedAuth: Buffer | undefined;
 
-  constructor(fedAuth: Buffer | undefined) {
+  /** Value of UTF8_SUPPORT acknowledgement.
+   *
+   * undefined when UTF8_SUPPORT not included in token. */
+  utf8Support: boolean | undefined;
+
+  constructor(fedAuth: Buffer | undefined, utf8Support: boolean | undefined) {
     super('FEATUREEXTACK', 'featureExtAck');
 
     this.fedAuth = fedAuth;
+    this.utf8Support = utf8Support;
   }
 }
 
diff --git a/test/unit/token/feature-ext-parser-test.js b/test/unit/token/feature-ext-parser-test.js
index 8ceff171f..d76b1d637 100644
--- a/test/unit/token/feature-ext-parser-test.js
+++ b/test/unit/token/feature-ext-parser-test.js
@@ -2,21 +2,21 @@ const StreamParser = require('../../../src/token/stream-parser');
 const WritableTrackingBuffer = require('../../../src/tracking-buffer/writable-tracking-buffer');
 const assert = require('chai').assert;
 
-describe('Feature Ext Praser', () => {
+describe('Feature Ext Parser', () => {
   it('should be fed authentication', async () => {
     const buffer = new WritableTrackingBuffer(50, 'ucs2');
 
     buffer.writeUInt8(0xAE); // FEATUREEXTACK token header
 
-    buffer.writeUInt8(0x01);
+    buffer.writeUInt8(0x01); // SESSIONRECOVERY
     buffer.writeUInt32LE(1);
     buffer.writeBuffer(Buffer.from('a'));
 
-    buffer.writeUInt8(0x02);
+    buffer.writeUInt8(0x02); // FEDAUTH
     buffer.writeUInt32LE(2);
     buffer.writeBuffer(Buffer.from('bc'));
 
-    buffer.writeUInt8(0x03);
+    buffer.writeUInt8(0x03); // made-up feature ext
     buffer.writeUInt32LE(0);
     buffer.writeBuffer(Buffer.from(''));
 
@@ -27,6 +27,28 @@ describe('Feature Ext Praser', () => {
     assert.isFalse(result.done);
     const token = result.value;
     assert.isOk(token.fedAuth.equals(Buffer.from('bc')));
+    assert.isUndefined(token.utf8Support); // feature ext ack for UTF8_SUPPORT was not received
+    assert.isTrue((await parser.next()).done);
+  });
+
+  it('should parse UTF-8 support token', async () => {
+    const buffer = new WritableTrackingBuffer(8);
+
+    buffer.writeUInt8(0xAE); // FEATUREEXTACK token header
+    buffer.writeUInt8(0x0A); // UTF8_SUPPORT feature id
+    buffer.writeUInt32LE(0x00_00_00_01); // datalen
+    buffer.writeUInt8(0x01); // supported
+
+    buffer.writeUInt8(0xFF); // TERMINATOR
+
+    const parser = StreamParser.parseTokens([buffer.data], {}, {});
+    const result = await parser.next();
+    assert.isFalse(result.done);
+
+    const token = result.value;
+    assert.strictEqual(token.utf8Support, true); // feature ext ack for UTF8_SUPPORT was positive
+    assert.isUndefined(token.fedAuth); // fed auth not ack'd
+
     assert.isTrue((await parser.next()).done);
   });
 });