NCBC-9383 Add ReplaceBodyWithXattr to MutateInSpec

Motivation
==========
This capability was added in 7.1.   Also, transactions has an
extension that uses it to gain a bit of efficiency.

Modification
============
Added the BucketCapability, then updated the MutateInSpec and
corresponding builder to support adding the new op code.

Results
=======
Added a new integration test, it passes.

Change-Id: Ie130c31bb632f8454774dd73f6fd792872d29cdc
Reviewed-on: https://review.couchbase.org/c/couchbase-net-client/+/225199
Reviewed-by: Jeffry Morris <jeffrymorris@gmail.com>
Tested-by: Build Bot <build@couchbase.com>

Author: davidkelly

src/Couchbase/Core/Configuration/Server/BucketCapabilities.cs

@@ -17,6 +17,7 @@ public static class BucketCapabilities
         public const string RANGE_SCAN = "rangeScan";
         public const string SUBDOC_REPLICA_READ = "subdoc.ReplicaRead";
         public const string NON_DEDUPED_HISTORY = "nonDedupedHistory";
+        public const string SUBDOC_REPLACE_BODY_WITH_XATTR = "subdoc.ReplaceBodyWithXattr";
     }
 }
 

src/Couchbase/Core/IO/Operations/OpCode.cs

@@ -84,6 +84,7 @@ public enum OpCode : byte
         MultiLookup = 0xd0,
         SubMultiMutation = 0xd1,
         SubGetCount = 0xd2,
+        SubReplaceBodyWithXattr = 0xd3,
 
         //the collections manifest
         GetCollectionsManifest = 0xBA,

src/Couchbase/Core/IO/Operations/SubDocument/MultiMutation.cs

@@ -109,7 +109,7 @@ protected override void WriteBody(OperationBuilder builder)
                     var pathLength = ByteConverter.FromString(mutate.Path, bufferSpan);
                     builder.Write(buffer, 0, pathLength);
 
-                    if (mutate.OpCode is not OpCode.SubDelete and not OpCode.Delete)
+                    if (mutate.OpCode is not OpCode.SubDelete and not OpCode.Delete and not OpCode.SubReplaceBodyWithXattr)
                     {
                         builder.AdvanceToSegment(OperationSegment.OperationSpecFragment);
                         mutate.WriteSpecValue(builder, Transcoder);

src/Couchbase/KeyValue/MutateInSpec.cs

@@ -156,6 +156,11 @@ public static MutateInSpec Decrement(string path, ulong delta, bool createPath =
             return CreateSpec(OpCode.SubCounter, path, -(long)delta, createPath, isXattr, removeBrackets);
         }
 
+        public static MutateInSpec ReplaceBodyWithXattr(string path)
+        {
+            return CreateSpec(OpCode.SubReplaceBodyWithXattr, path, false, true, false);
+        }
+
         /// <summary>
         /// Serializes the <see cref="OperationSpec.Value" /> to the <see cref="OperationBuilder"/> using the <see cref="ITypeTranscoder"/>.
         /// </summary>

src/Couchbase/KeyValue/MutateInSpecBuilder.cs

@@ -243,6 +243,12 @@ public MutateInSpecBuilder SetDoc<T>(T value)
             Specs.Add(MutateInSpec.Decrement(path, delta, createPath, isXattr));
             return this;
         }
+
+        public MutateInSpecBuilder ReplaceBodyWithXattr(string path)
+        {
+            Specs.Add(MutateInSpec.ReplaceBodyWithXattr(path));
+            return this;
+        }
     }
 }
 

tests/Couchbase.IntegrationTests/SubdocTests.cs

@@ -542,6 +542,33 @@ public async Task MutateIn_SetDoc_UsesTranscoder()
             //Assert.Equal("foo", result.ContentAs<string>(1));
         }
 
+        [Fact]
+        public async Task MutateIn_ReplaceBodyWithXattr_Succeeds()
+        {
+            var collection = await _fixture.GetDefaultCollectionAsync().ConfigureAwait(false);
+            var documentKey = nameof(MutateIn_ReplaceBodyWithXattr_Succeeds);
+            await collection.UpsertAsync(documentKey, new { foo = "bar", bar = "foo", xxx = 0 }).ConfigureAwait(false);
+            var newDocBody = new { bar = "foo2", foo = "bar2", xxx = 3 };
+
+            // put the newDocBody in test_attr xattr...
+            using (await collection.MutateInAsync(documentKey, builder =>
+            {
+                builder.Upsert("test_attr", newDocBody, isXattr: true, createPath: true);
+            }));
+
+            using (await collection.MutateInAsync(documentKey, builder =>
+            {
+                builder.ReplaceBodyWithXattr("test_attr");
+            }));
+
+            // verify the document body changed.  NOTE: by comparing as strings, we run the risk
+            // of having the order change though the key/value pairs are all equal. If you change
+            // the newDocBody (or the old one), you may need to adjust the order of one or the
+            // other to match.
+            var getResult = await collection.GetAsync(documentKey, options => options.Transcoder(new LegacyTranscoder())).ConfigureAwait(false);
+            Assert.Equal(getResult.ContentAs<string>(), JsonConvert.SerializeObject(newDocBody));
+        }
+
         #region Helpers
 
         private class TestDoc