Make IChangeContext interface (#26)

* Create IChangeContext interface in core

Commit property in interface is CommitBase rather than Commit.

* Include harmony core in global usings
* Remove now-unneeded `using SIL.Harmony.Core` lines
* Create IObjectSnapshot interface in core

ObjectSnapshot relies on too many things from the DB to be moved to core
easily, so we leave it in SIL.Harmony.Db and create an interface in core
instead. Then the only difference is that the type of Commit will be
different depending on whether you access it via the interface (in which
case you'll get a CommitBase from core) or via the implementation
class (in which case you'll get a Commit object from SIL.Harmony).

* Tweak IChangeContext to use IObjectSnapshot
* Use interface in NewEntity and ApplyChange

The Change.NewEntity and Change.ApplyChange methods, as well as the
overriding/implementing methods in all Change subclasses, should now
take an IChangeContext so that it can be mocked for testing.

* Update RemoveReference methods to use CommitBase

Now that IObjectBase uses CommitBase in RemoveReference, its
implementing classes need to use the base type too.

* Pull GetObjectsReferencing into IChangeContext 
* Remove un-needed GetCurrent method from ChangeContext

---------

Co-authored-by: Kevin Hahn <kevin_hahn@sil.org>

Author: rmunn

README.md

@@ -69,7 +69,7 @@ public class SetWordTextChange(Guid entityId, string text) : Change<Word>(entity
 {
     public string Text { get; } = text;
 
-    public override ValueTask<IObjectBase> NewEntity(Commit commit, ChangeContext context)
+    public override ValueTask<IObjectBase> NewEntity(Commit commit, IChangeContext context)
     {
         return new(new Word()
         {
@@ -79,7 +79,7 @@ public class SetWordTextChange(Guid entityId, string text) : Change<Word>(entity
     }
 
 
-    public override ValueTask ApplyChange(Word entity, ChangeContext context)
+    public override ValueTask ApplyChange(Word entity, IChangeContext context)
     {
         entity.Text = Text;
         return ValueTask.CompletedTask;

src/SIL.Harmony.Core/IChangeContext.cs

@@ -0,0 +1,17 @@
+namespace SIL.Harmony.Core;
+
+public interface IChangeContext
+{
+    public CommitBase Commit { get; }
+    ValueTask<IObjectSnapshot?> GetSnapshot(Guid entityId);
+    public async ValueTask<T?> GetCurrent<T>(Guid entityId) where T : class
+    {
+        var snapshot = await GetSnapshot(entityId);
+        if (snapshot is null) return null;
+        return (T) snapshot.Entity.DbObject;
+    }
+
+    public async ValueTask<bool> IsObjectDeleted(Guid entityId) => (await GetSnapshot(entityId))?.EntityIsDeleted ?? true;
+    internal IObjectBase Adapt(object obj);
+    IAsyncEnumerable<object> GetObjectsReferencing(Guid entityId, bool includeDeleted = false);
+}

src/SIL.Harmony.Core/IObjectBase.cs

@@ -0,0 +1,35 @@
+using System.Text.Json.Serialization;
+
+namespace SIL.Harmony.Core;
+
+[JsonPolymorphic]
+public interface IObjectBase
+{
+    Guid Id { get; }
+    DateTimeOffset? DeletedAt { get; set; }
+
+    /// <summary>
+    /// provides the references this object has to other objects, when those objects are deleted
+    /// <see cref="RemoveReference"/> will be called to remove the reference
+    /// </summary>
+    /// <returns></returns>
+    public Guid[] GetReferences();
+    /// <summary>
+    /// remove a reference to another object, in some cases this may cause this object to be deleted
+    /// </summary>
+    /// <param name="id">id of the deleted object</param>
+    /// <param name="commit">
+    /// commit where the reference was removed
+    /// should be used to set the deleted date for this object
+    /// </param>
+    public void RemoveReference(Guid id, CommitBase commit);
+
+    public IObjectBase Copy();
+    /// <summary>
+    /// the name of the object type, this is used to discriminate between different types of objects in the snapshots table
+    /// </summary>
+    /// <returns>a stable type name of this object, should not change over time</returns>
+    public string GetObjectTypeName();
+    [JsonIgnore]
+    public object DbObject { get; }
+}

src/SIL.Harmony.Core/IObjectSnapshot.cs

@@ -0,0 +1,14 @@
+namespace SIL.Harmony.Core;
+
+public interface IObjectSnapshot
+{
+    Guid Id { get; }
+    string TypeName { get; }
+    IObjectBase Entity { get; }
+    Guid[] References { get; }
+    Guid EntityId { get; }
+    bool EntityIsDeleted { get; }
+    Guid CommitId { get; }
+    CommitBase Commit { get; }
+    bool IsRoot { get; }
+}

src/SIL.Harmony.Core/QueryHelpers.cs

@@ -1,4 +1,4 @@
-using Microsoft.EntityFrameworkCore;
+using Microsoft.EntityFrameworkCore;
 
 namespace SIL.Harmony.Core;
 

src/SIL.Harmony.Sample/Changes/AddAntonymReferenceChange.cs

@@ -9,7 +9,7 @@ public class AddAntonymReferenceChange(Guid entityId, Guid antonymId)
 {
     public Guid AntonymId { get; set; } = antonymId;
 
-    public override async ValueTask ApplyChange(Word entity, ChangeContext context)
+    public override async ValueTask ApplyChange(Word entity, IChangeContext context)
     {
         //if the word being referenced was deleted before this change was applied (could happen after a sync)
         //then we don't want to apply the change

src/SIL.Harmony.Sample/Changes/AddWordImageChange.cs

@@ -8,7 +8,7 @@ public class AddWordImageChange(Guid entityId, Guid imageId) : EditChange<Word>(
 {
     public Guid ImageId { get; } = imageId;
 
-    public override async ValueTask ApplyChange(Word entity, ChangeContext context)
+    public override async ValueTask ApplyChange(Word entity, IChangeContext context)
     {
         if (!await context.IsObjectDeleted(ImageId)) entity.ImageResourceId = ImageId;
     }

src/SIL.Harmony.Sample/Changes/EditExampleChange.cs

@@ -26,7 +26,7 @@ public EditExampleChange(Guid entityId, string updateBlob) : base(entityId)
 
     public string UpdateBlob { get; set; }
 
-    public override ValueTask ApplyChange(Example entity, ChangeContext context)
+    public override ValueTask ApplyChange(Example entity, IChangeContext context)
     {
         entity.YText.Doc.ApplyUpdateV2(Convert.FromBase64String(UpdateBlob));
         return ValueTask.CompletedTask;

src/SIL.Harmony.Sample/Changes/NewDefinitionChange.cs

@@ -12,7 +12,7 @@ public class NewDefinitionChange(Guid entityId) : CreateChange<Definition>(entit
     public required double Order { get; set; }
     public required Guid WordId { get; init; }
 
-    public override async ValueTask<Definition> NewEntity(Commit commit, ChangeContext context)
+    public override async ValueTask<Definition> NewEntity(Commit commit, IChangeContext context)
     {
         return new Definition
         {

src/SIL.Harmony.Sample/Changes/NewExampleChange.cs

@@ -34,7 +34,7 @@ private NewExampleChange(Guid entityId) : base(entityId)
     {
     }
 
-    public override async ValueTask<Example> NewEntity(Commit commit, ChangeContext context)
+    public override async ValueTask<Example> NewEntity(Commit commit, IChangeContext context)
     {
         return new Example
         {

src/SIL.Harmony.Sample/Changes/NewWordChange.cs

@@ -10,7 +10,7 @@ public class NewWordChange(Guid entityId, string text, string? note = null, Guid
     public string? Note { get; } = note;
     public Guid? AntonymId { get; } = antonymId;
 
-    public override async ValueTask<Word> NewEntity(Commit commit, ChangeContext context)
+    public override async ValueTask<Word> NewEntity(Commit commit, IChangeContext context)
     {
         var antonymShouldBeNull = AntonymId is null || (await context.IsObjectDeleted(AntonymId.Value));
         return (new Word { Text = Text, Note = Note, Id = EntityId, AntonymId = antonymShouldBeNull ? null : AntonymId });

src/SIL.Harmony.Sample/Changes/SetDefinitionPartOfSpeechChange.cs

@@ -8,7 +8,7 @@ public class SetDefinitionPartOfSpeechChange(Guid entityId, string partOfSpeech)
 {
     public string PartOfSpeech { get; } = partOfSpeech;
 
-    public override ValueTask ApplyChange(Definition entity, ChangeContext context)
+    public override ValueTask ApplyChange(Definition entity, IChangeContext context)
     {
         entity.PartOfSpeech = PartOfSpeech;
         return ValueTask.CompletedTask;

src/SIL.Harmony.Sample/Changes/SetTagChange.cs

@@ -8,7 +8,7 @@ public class SetTagChange(Guid entityId, string text) : Change<Tag>(entityId), I
 {
     public string Text { get; } = text;
 
-    public override ValueTask<Tag> NewEntity(Commit commit, ChangeContext context)
+    public override ValueTask<Tag> NewEntity(Commit commit, IChangeContext context)
     {
         return new(new Tag()
         {
@@ -18,7 +18,7 @@ public override ValueTask<Tag> NewEntity(Commit commit, ChangeContext context)
     }
 
 
-    public override ValueTask ApplyChange(Tag entity, ChangeContext context)
+    public override ValueTask ApplyChange(Tag entity, IChangeContext context)
     {
         entity.Text = Text;
         return ValueTask.CompletedTask;

src/SIL.Harmony.Sample/Changes/SetWordNoteChange.cs

@@ -8,7 +8,7 @@ public class SetWordNoteChange(Guid entityId, string note) : EditChange<Word>(en
 {
     public string Note { get; } = note;
 
-    public override ValueTask ApplyChange(Word entity, ChangeContext context)
+    public override ValueTask ApplyChange(Word entity, IChangeContext context)
     {
         entity.Note = Note;
         return ValueTask.CompletedTask;

src/SIL.Harmony.Sample/Changes/SetWordTextChange.cs

@@ -12,7 +12,7 @@ public class SetWordTextChange(Guid entityId, string text) : Change<Word>(entity
 {
     public string Text { get; } = text;
 
-    public override ValueTask<Word> NewEntity(Commit commit, ChangeContext context)
+    public override ValueTask<Word> NewEntity(Commit commit, IChangeContext context)
     {
         return new(new Word()
         {
@@ -22,7 +22,7 @@ public override ValueTask<Word> NewEntity(Commit commit, ChangeContext context)
     }
 
 
-    public override ValueTask ApplyChange(Word entity, ChangeContext context)
+    public override ValueTask ApplyChange(Word entity, IChangeContext context)
     {
         entity.Text = Text;
         return ValueTask.CompletedTask;

src/SIL.Harmony.Sample/CrdtSampleKernel.cs

@@ -1,4 +1,3 @@
-using System.Data.Common;
 using System.Diagnostics;
 using SIL.Harmony.Changes;
 using SIL.Harmony.Linq2db;

src/SIL.Harmony.Sample/Models/Definition.cs

@@ -18,7 +18,7 @@ public Guid[] GetReferences()
         return [WordId];
     }
 
-    public void RemoveReference(Guid id, Commit commit)
+    public void RemoveReference(Guid id, CommitBase commit)
     {
         if (WordId == id)
         {

src/SIL.Harmony.Sample/Models/Example.cs

@@ -31,7 +31,7 @@ public Guid[] GetReferences()
         return [DefinitionId];
     }
 
-    public void RemoveReference(Guid id, Commit commit)
+    public void RemoveReference(Guid id, CommitBase commit)
     {
         if (DefinitionId == id)
         {

src/SIL.Harmony.Sample/Models/Tag.cs

@@ -14,7 +14,7 @@ public Guid[] GetReferences()
         return [];
     }
 
-    public void RemoveReference(Guid id, Commit commit)
+    public void RemoveReference(Guid id, CommitBase commit)
     {
     }
 

src/SIL.Harmony.Sample/Models/Word.cs

@@ -23,7 +23,7 @@ IEnumerable<Guid> Refs()
         }
     }
 
-    public void RemoveReference(Guid id, Commit commit)
+    public void RemoveReference(Guid id, CommitBase commit)
     {
         if (AntonymId == id) AntonymId = null;
     }

src/SIL.Harmony.Sample/SIL.Harmony.Sample.csproj

@@ -10,4 +10,7 @@
       <ProjectReference Include="..\Ycs\Ycs.csproj" />
     </ItemGroup>
 
+    <ItemGroup>
+        <Using Include="SIL.Harmony.Core"/>
+    </ItemGroup>
 </Project>

src/SIL.Harmony.Sample/SampleDbContext.cs

@@ -1,5 +1,4 @@
 using SIL.Harmony.Changes;
-using SIL.Harmony.Core;
 using SIL.Harmony.Db;
 using Microsoft.EntityFrameworkCore;
 using Microsoft.Extensions.Options;

src/SIL.Harmony.Tests/Adapter/CustomObjectAdapterTests.cs

@@ -6,7 +6,6 @@
 using SIL.Harmony.Changes;
 using SIL.Harmony.Db;
 using SIL.Harmony.Entities;
-using SIL.Harmony.Linq2db;
 
 namespace SIL.Harmony.Tests.Adapter;
 
@@ -108,7 +107,7 @@ public DateTimeOffset? DeletedAt
 
         public Guid[] GetReferences() => [];
 
-        public void RemoveReference(Guid id, Commit commit)
+        public void RemoveReference(Guid id, CommitBase commit)
         {
         }
 
@@ -124,7 +123,7 @@ public CreateMyClassChange(MyClass entity) : base(entity.Identifier)
             _entity = entity;
         }
 
-        public override ValueTask<MyClass> NewEntity(Commit commit, ChangeContext context)
+        public override ValueTask<MyClass> NewEntity(Commit commit, IChangeContext context)
         {
             return ValueTask.FromResult(_entity);
         }
@@ -139,7 +138,7 @@ public CreateMyClass2Change(MyClass2 entity) : base(entity.Identifier)
             _entity = entity;
         }
 
-        public override ValueTask<MyClass2> NewEntity(Commit commit, ChangeContext context)
+        public override ValueTask<MyClass2> NewEntity(Commit commit, IChangeContext context)
         {
             return ValueTask.FromResult(_entity);
         }

src/SIL.Harmony.Tests/CommitTests.cs

@@ -1,7 +1,6 @@
 using System.IO.Hashing;
 using System.Text.Json;
 using SIL.Harmony.Changes;
-using SIL.Harmony.Core;
 using SIL.Harmony.Sample;
 using SIL.Harmony.Sample.Changes;
 using Microsoft.Extensions.DependencyInjection;

src/SIL.Harmony.Tests/Core/HybridDateTimeTests.cs

@@ -1,5 +1,3 @@
-using SIL.Harmony.Core;
-
 namespace SIL.Harmony.Tests.Core;
 
 public class HybridDateTimeTests

src/SIL.Harmony.Tests/DataModelPerformanceTests.cs

@@ -8,12 +8,9 @@
 using BenchmarkDotNet.Loggers;
 using BenchmarkDotNet.Running;
 using JetBrains.Profiler.SelfApi;
-using Microsoft.Data.Sqlite;
 using SIL.Harmony.Changes;
-using SIL.Harmony.Core;
 using SIL.Harmony.Db;
 using SIL.Harmony.Sample.Changes;
-using SIL.Harmony.Sample.Models;
 using Xunit.Abstractions;
 
 namespace SIL.Harmony.Tests;

src/SIL.Harmony.Tests/DataModelTestBase.cs

@@ -1,15 +1,12 @@
-using System.Data.Common;
 using Microsoft.Data.Sqlite;
 using SIL.Harmony.Changes;
-using SIL.Harmony.Core;
 using SIL.Harmony.Sample;
 using SIL.Harmony.Sample.Changes;
 using SIL.Harmony.Sample.Models;
 using SIL.Harmony.Tests.Mocks;
 using Microsoft.EntityFrameworkCore;
 using Microsoft.Extensions.DependencyInjection;
 using Microsoft.Extensions.DependencyInjection.Extensions;
-using Microsoft.Extensions.Options;
 using SIL.Harmony.Db;
 
 namespace SIL.Harmony.Tests;

src/SIL.Harmony.Tests/Db/QueryHelperTests.cs

@@ -1,4 +1,3 @@
-using SIL.Harmony.Core;
 using SIL.Harmony.Db;
 using SIL.Harmony.Tests.Mocks;
 

src/SIL.Harmony.Tests/DbContextTests.cs

@@ -1,4 +1,3 @@
-using SIL.Harmony.Core;
 using LinqToDB;
 using LinqToDB.EntityFrameworkCore;
 using Microsoft.EntityFrameworkCore;

src/SIL.Harmony.Tests/Mocks/MockTimeProvider.cs

@@ -1,5 +1,3 @@
-using SIL.Harmony.Core;
-
 namespace SIL.Harmony.Tests.Mocks;
 
 public class MockTimeProvider: IHybridDateTimeProvider

src/SIL.Harmony.Tests/ModuleInit.cs

@@ -1,7 +1,6 @@
-using System.Linq.Expressions;
+using System.Linq.Expressions;
 using System.Runtime.CompilerServices;
 using Argon;
-using SIL.Harmony.Core;
 using SIL.Harmony.Sample;
 using Microsoft.Extensions.DependencyInjection;
 

src/SIL.Harmony.Tests/ObjectBaseTestingHelpers.cs

@@ -1,5 +1,3 @@
-using SIL.Harmony.Entities;
-
 namespace SIL.Harmony.Tests;
 
 public static class ObjectBaseTestingHelpers

src/SIL.Harmony.Tests/PersistExtraDataTests.cs

@@ -1,9 +1,6 @@
 using Microsoft.Extensions.DependencyInjection;
-using Microsoft.Extensions.DependencyInjection.Extensions;
 using SIL.Harmony.Changes;
-using SIL.Harmony.Core;
 using SIL.Harmony.Entities;
-using SIL.Harmony.Sample;
 
 namespace SIL.Harmony.Tests;
 
@@ -13,7 +10,7 @@ public class PersistExtraDataTests
 
     public class CreateExtraDataModelChange(Guid entityId) : CreateChange<ExtraDataModel>(entityId), ISelfNamedType<CreateExtraDataModelChange>
     {
-        public override ValueTask<ExtraDataModel> NewEntity(Commit commit, ChangeContext context)
+        public override ValueTask<ExtraDataModel> NewEntity(Commit commit, IChangeContext context)
         {
             return ValueTask.FromResult(new ExtraDataModel()
             {
@@ -35,7 +32,7 @@ public Guid[] GetReferences()
             return [];
         }
 
-        public void RemoveReference(Guid id, Commit commit)
+        public void RemoveReference(Guid id, CommitBase commit)
         {
         }
 

src/SIL.Harmony.Tests/RepositoryTests.cs

@@ -1,4 +1,3 @@
-using SIL.Harmony.Core;
 using SIL.Harmony.Db;
 using SIL.Harmony.Sample;
 using SIL.Harmony.Sample.Models;