CBL-7277 CBL-7281 (#1718)

Enable version vector functionality and tests, and change Timestamp to ulong instead of DateTimeOffset

Also add in an extension to create a DateTimeOffset from the ulong

Author: borrrden

src/Couchbase.Lite.Shared/API/Database/Database.cs

@@ -104,7 +104,7 @@ public sealed unsafe partial class Database : IDisposable
         #region Constants
 
         private static readonly C4DatabaseConfig2 DBConfig = new C4DatabaseConfig2 {
-            flags = C4DatabaseFlags.Create | C4DatabaseFlags.AutoCompact
+            flags = C4DatabaseFlags.Create | C4DatabaseFlags.AutoCompact | C4DatabaseFlags.VersionVectors
         };
 
         private const string DBExtension = "cblite2";

src/Couchbase.Lite.Shared/API/Document/Document.cs

@@ -34,15 +34,36 @@
 
 namespace Couchbase.Lite
 {
+    /// <summary>
+    /// An extension class for helping to turn a nanosecond based timestamp into a
+    /// <see cref="DateTimeOffset"/> object
+    /// </summary>
+    public static class TimestampExtensions
+    {
+        private static readonly DateTime UnixEpoch = new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc);
+        
+        /// <summary>
+        /// Converts the nanosecond timestamp to a DateTimeOffset in UTC time
+        /// </summary>
+        /// <param name="rawVal">The nanosecond timestamp</param>
+        /// <returns>The DateTimeOffset object using the timestamp, or null if it was invalid</returns>
+        public static DateTimeOffset? AsDateTimeOffset(this ulong rawVal)
+        {
+            if(rawVal == 0) {
+                return null;
+            }
+
+            // .NET ticks are in 100 nanosecond intervals
+            return UnixEpoch + TimeSpan.FromTicks((long)(rawVal / 100));
+        }
+    }
     /// <summary>
     /// A class representing a document which cannot be altered
     /// </summary>
     public unsafe class Document : IDictionaryObject, IJSON, IDisposable
     {
         private const string Tag = nameof(Document);
 
-        private static readonly DateTimeOffset UnixEpoch = new DateTimeOffset(1970, 1, 1, 0, 0, 0, TimeSpan.Zero);
-
         #region Variables
 
         private string? _revId;
@@ -65,16 +86,16 @@ public unsafe class Document : IDictionaryObject, IJSON, IDisposable
         internal C4DatabaseWrapper c4Db
         {
             get {
-                Debug.Assert(Database != null && Database.c4db != null);
-                return Database!.c4db!;
+                Debug.Assert(Database is { c4db: not null });
+                return Database.c4db;
             }
         }
 
         internal C4CollectionWrapper c4Coll
         {
             get {
-                Debug.Assert(Collection != null && Collection.c4coll != null);
-                return Collection!.c4coll!;
+                Debug.Assert(Collection != null);
+                return Collection!.c4coll;
             }
         }
 
@@ -164,25 +185,16 @@ public string? RevisionID
         }
 
         /// <summary>
-        /// The hybrid logical timestamp that the revision was created.
+        /// The hybrid logical timestamp that the revision was created, represented in nanoseconds
+        /// from the unix epoch.  If you want this value as a DateTimeOffset you can use the
+        /// convenience function <see cref="TimestampExtensions.AsDateTimeOffset(ulong)">AsDateTimeOffset</see>.
+        /// Just be aware that DateTimeOffset only handles 100 nanosecond resolution.
         /// </summary>
-        public DateTimeOffset? Timestamp
+        public ulong Timestamp
         {
             get {
                 using var scope = ThreadSafety.BeginLockedScope();
-                var rawVal = c4Doc?.HasValue == true ? NativeRaw.c4rev_getTimestamp(c4Doc.RawDoc->selectedRev.revID) : 0;
-                if(rawVal == 0) {
-                    return null;
-                }
-
-                // .NET ticks are in 100 nanosecond intervals
-                rawVal /= 100;
-
-                if(rawVal > Int64.MaxValue) {
-                    throw new OverflowException("The returned value from LiteCore is too large to be represented by DateTimeOffset");
-                }
-
-                return UnixEpoch + TimeSpan.FromTicks((long)rawVal);
+                return c4Doc?.HasValue == true ? NativeRaw.c4rev_getTimestamp(c4Doc.RawDoc->selectedRev.revID) : 0;
             }
         }
 

src/Couchbase.Lite.Tests.Shared/VersionVectorTests.cs

@@ -48,16 +48,16 @@ public VersionVectorTest(ITestOutputHelper output) : base(output)
     ///     5. Get the document id = "doc1" from the database.
     ///     6. Get document's timestamp and check that the timestamp is the same as the timestamp from step 4.
     /// </summary>
-    [Fact(Skip = "Version vectors not turned on yet")]
+    [Fact]
     public void TestDocumentTimestamp()
     {
         using var doc = new MutableDocument("doc1");
-        doc.Timestamp.ShouldBeNull("because the doc has not been saved yet");
+        doc.Timestamp.ShouldBe(0UL, "because the doc has not been saved yet");
         DefaultCollection.Save(doc);
-        doc.Timestamp.ShouldNotBeNull("because the doc is now saved");
+        doc.Timestamp.ShouldNotBe(0UL, "because the doc is now saved");
         using var savedDoc = DefaultCollection.GetDocument("doc1");
         savedDoc.ShouldNotBeNull("because the document was just saved");
-        savedDoc!.Timestamp.ShouldBe(doc.Timestamp, "because the timestamp should not change just from a read");
+        savedDoc.Timestamp.ShouldBe(doc.Timestamp, "because the timestamp should not change just from a read");
     }
 
     /// <summary>
@@ -72,7 +72,7 @@ public void TestDocumentTimestamp()
     ///     5. Get the document id = "doc1" from the database.
     ///     6. Get document's _revisionIDs and check that the value returned is not null
     /// </summary>
-    [Fact(Skip = "Version vectors not turned on yet")]
+    [Fact]
     public void TestDocumentRevisionHistory()
     {
         using var doc = new MutableDocument("doc1");
@@ -82,7 +82,7 @@ public void TestDocumentRevisionHistory()
         using var savedDoc = DefaultCollection.GetDocument("doc1");
         savedDoc.ShouldNotBeNull("because the document was just saved");
 
-        savedDoc!.RevisionIDs().ShouldNotBeNull("because the saved document should contain at least one revision ID");
+        savedDoc.RevisionIDs().ShouldNotBeNull("because the saved document should contain at least one revision ID");
     }
 
     public enum DefaultConflictLWWMode
@@ -110,7 +110,7 @@ public enum DefaultConflictLWWMode
     ///     6.Start a single shot pull replicator to pull documents from "db2" to "db1".
     ///     7. Get the document "doc2" from "db1" and check that the content is {"key": "value2"}.
     /// </summary>
-    [Theory(Skip = "Version vectors not turned on yet")]
+    [Theory]
     [InlineData(DefaultConflictLWWMode.SaveDB2First)]
     [InlineData(DefaultConflictLWWMode.SaveDB1First)]
     public void TestDefaultConflictResolver(DefaultConflictLWWMode lwwMode)
@@ -148,7 +148,7 @@ public void TestDefaultConflictResolver(DefaultConflictLWWMode lwwMode)
 
         using var doc = db1.GetDefaultCollection().GetDocument("doc1");
         doc.ShouldNotBeNull("because it was just saved");
-        doc!["key"].Value.ShouldBe(expectedValue, "because otherwise the conflict resolver behaved unexpectedly");
+        doc["key"].Value.ShouldBe(expectedValue, "because otherwise the conflict resolver behaved unexpectedly");
     }
 
     /// <summary>
@@ -168,7 +168,7 @@ public void TestDefaultConflictResolver(DefaultConflictLWWMode lwwMode)
     ///     4.Start a single shot pull replicator to pull documents from "db2" to "db1".
     ///     5. Get the document "doc1" from "db1" and check that the returned document is null.
     /// </summary>
-    [Fact(Skip = "Version vectors not turned on yet")]
+    [Fact]
     public void TestDefaultConflictResolverDeleteWins()
     {
         Database.Delete("db1", null);