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ChrisJollyAUChrisJollyAU
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Create a new sequential guid generator based on the UUID version 7 (#254)
* Create a new sequential guid generator based on the UUID version 7
1 parent 2159969 commit f97148f

5 files changed

Lines changed: 130 additions & 2 deletions

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‎src/EFCore.Jet/ValueGeneration/Internal/JetValueGeneratorSelector.cs‎

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -42,7 +42,7 @@ public JetValueGeneratorSelector(
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=> property.ClrType.UnwrapNullableType() == typeof(Guid)
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? property.ValueGenerated == ValueGenerated.Never || property.GetDefaultValueSql() != null
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? new TemporaryGuidValueGenerator()
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: new SequentialGuidValueGenerator()
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: new JetSequentialGuidValueGenerator()
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: base.FindForType(property, typeBase, clrType);
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}
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}

‎src/EFCore.Jet/ValueGeneration/JetSequentialGuidValueGenerator.cs‎

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Original file line numberDiff line numberDiff line change
@@ -0,0 +1,66 @@
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using EntityFrameworkCore.Jet.Utilities;
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using Microsoft.EntityFrameworkCore.ChangeTracking;
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using Microsoft.EntityFrameworkCore.ValueGeneration;
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using System;
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using System.Runtime.InteropServices;
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using System.Threading;
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namespace EntityFrameworkCore.Jet.ValueGeneration;
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/// <summary>
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/// Generates sequential <see cref="Guid" /> values according to the UUID version 7 specification.
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/// Will be updated to use <see cref="Guid.CreateVersion7"/> when available.
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/// </summary>
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public class JetSequentialGuidValueGenerator : ValueGenerator<Guid>
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{
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private long _counter = DateTime.UtcNow.Ticks;
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private const byte Variant10xxValue = 0x80;
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private const ushort Version7Value = 0x7000;
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private const ushort VersionMask = 0xF000;
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private const byte Variant10xxMask = 0xC0;
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/// <summary>
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/// Gets a value to be assigned to a property.
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/// </summary>
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/// <param name="entry">The change tracking entry of the entity for which the value is being generated.</param>
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/// <returns>The value to be assigned to a property.</returns>
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public override Guid Next(EntityEntry entry)
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{
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Span<byte> guidBytes = stackalloc byte[16];
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var succeeded = Guid.NewGuid().TryWriteBytes(guidBytes);
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var incrementedCounter = Interlocked.Increment(ref _counter);
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Span<byte> counterBytes = stackalloc byte[sizeof(long)];
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MemoryMarshal.Write(counterBytes, in incrementedCounter);
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if (!BitConverter.IsLittleEndian)
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{
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counterBytes.Reverse();
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}
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//unix ts ms - 48 bits (6 bytes)
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guidBytes[00] = counterBytes[2];
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guidBytes[01] = counterBytes[3];
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guidBytes[02] = counterBytes[4];
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guidBytes[03] = counterBytes[5];
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guidBytes[04] = counterBytes[0];
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guidBytes[05] = counterBytes[1];
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//UIDv7 version - first 4 bits (1/2 byte) of the next 16 bits (2 bytes)
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var _c = BitConverter.ToInt16(guidBytes.Slice(6, 2));
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_c = (short)((_c & ~VersionMask) | Version7Value);
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BitConverter.TryWriteBytes(guidBytes.Slice(6, 2), _c);
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//2 bit variant
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//first 2 bits of the next 64 bits (8 bytes)
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guidBytes[8] = (byte)((guidBytes[8] & ~Variant10xxMask) | Variant10xxValue);
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return new Guid(guidBytes);
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}
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/// <summary>
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/// Gets a value indicating whether the values generated are temporary or permanent. This implementation
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/// always returns false, meaning the generated values will be saved to the database.
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/// </summary>
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public override bool GeneratesTemporaryValues
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=> false;
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}

‎test/EFCore.Jet.FunctionalTests/GreenTests/ace_2010_odbc_x86.txt‎

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Original file line numberDiff line numberDiff line change
@@ -19114,6 +19114,8 @@ EntityFrameworkCore.Jet.FunctionalTests.SeedingJetTest.Seeding_does_not_leave_co
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EntityFrameworkCore.Jet.FunctionalTests.SeedingJetTest.Seeding_keyless_entity_throws_exception(async: False)
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EntityFrameworkCore.Jet.FunctionalTests.SeedingJetTest.Seeding_keyless_entity_throws_exception(async: True)
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EntityFrameworkCore.Jet.FunctionalTests.SequentialGuidEndToEndTest.Can_use_explicit_values
19117+
EntityFrameworkCore.Jet.FunctionalTests.SequentialGuidEndToEndTest.Can_use_sequential_GUID_end_to_end_async
19118+
EntityFrameworkCore.Jet.FunctionalTests.SequentialGuidEndToEndTest.CustomUuid7Test
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EntityFrameworkCore.Jet.FunctionalTests.SerializationJetTest.Can_round_trip_through_JSON(useNewtonsoft: False, ignoreLoops: False, writeIndented: False)
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EntityFrameworkCore.Jet.FunctionalTests.SerializationJetTest.Can_round_trip_through_JSON(useNewtonsoft: False, ignoreLoops: False, writeIndented: True)
1911919121
EntityFrameworkCore.Jet.FunctionalTests.SerializationJetTest.Can_round_trip_through_JSON(useNewtonsoft: True, ignoreLoops: False, writeIndented: False)

‎test/EFCore.Jet.FunctionalTests/GreenTests/ace_2010_oledb_x86.txt‎

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Original file line numberDiff line numberDiff line change
@@ -22747,6 +22747,8 @@ EntityFrameworkCore.Jet.FunctionalTests.SeedingJetTest.Seeding_does_not_leave_co
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EntityFrameworkCore.Jet.FunctionalTests.SeedingJetTest.Seeding_keyless_entity_throws_exception(async: False)
2274822748
EntityFrameworkCore.Jet.FunctionalTests.SeedingJetTest.Seeding_keyless_entity_throws_exception(async: True)
2274922749
EntityFrameworkCore.Jet.FunctionalTests.SequentialGuidEndToEndTest.Can_use_explicit_values
22750+
EntityFrameworkCore.Jet.FunctionalTests.SequentialGuidEndToEndTest.Can_use_sequential_GUID_end_to_end_async
22751+
EntityFrameworkCore.Jet.FunctionalTests.SequentialGuidEndToEndTest.CustomUuid7Test
2275022752
EntityFrameworkCore.Jet.FunctionalTests.SerializationJetTest.Can_round_trip_through_JSON(useNewtonsoft: False, ignoreLoops: False, writeIndented: False)
2275122753
EntityFrameworkCore.Jet.FunctionalTests.SerializationJetTest.Can_round_trip_through_JSON(useNewtonsoft: False, ignoreLoops: False, writeIndented: True)
2275222754
EntityFrameworkCore.Jet.FunctionalTests.SerializationJetTest.Can_round_trip_through_JSON(useNewtonsoft: True, ignoreLoops: False, writeIndented: False)

‎test/EFCore.Jet.FunctionalTests/SequentialGuidEndToEndTest.cs‎

Lines changed: 59 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -4,12 +4,17 @@
44
using System.Collections.Generic;
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using EntityFrameworkCore.Jet.Data;
66
using System.Linq;
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using System.Threading;
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using System.Threading.Tasks;
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using EntityFrameworkCore.Jet.FunctionalTests.TestUtilities;
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using Microsoft.EntityFrameworkCore;
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using Microsoft.EntityFrameworkCore.TestUtilities;
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using Microsoft.Extensions.DependencyInjection;
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using Xunit;
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using Microsoft.EntityFrameworkCore.ChangeTracking;
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using Microsoft.EntityFrameworkCore.ValueGeneration;
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using System.Diagnostics.Metrics;
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using System.Runtime.InteropServices;
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#nullable disable
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// ReSharper disable InconsistentNaming
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namespace EntityFrameworkCore.Jet.FunctionalTests
@@ -29,7 +34,7 @@ public async Task Can_use_sequential_GUID_end_to_end_async()
2934

3035
for (var i = 0; i < 50; i++)
3136
{
32-
context.Add(
37+
await context.AddAsync(
3338
new Pegasus { Name = "Rainbow Dash " + i });
3439
}
3540

@@ -115,5 +120,58 @@ public Task DisposeAsync()
115120
TestStore.Dispose();
116121
return Task.CompletedTask;
117122
}
123+
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[ConditionalFact]
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public void CustomUuid7Test()
126+
{
127+
DateTimeOffset dtoNow = DateTimeOffset.UtcNow;
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Guid net9internal = Guid.CreateVersion7(dtoNow);
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Guid custom = Next(dtoNow);
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var bytenet9 = net9internal.ToByteArray().AsSpan(0, 6);
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var bytecustom = custom.ToByteArray().AsSpan(0,6);
132+
Assert.Equal(bytenet9,bytecustom);
133+
Assert.Equal(net9internal.Version,custom.Version);
134+
var t1 = net9internal.Variant & Variant10xxMask;
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var t2 = BitConverter.GetBytes(custom.Variant);
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Assert.InRange(net9internal.Variant,8,0xB);
137+
Assert.InRange(custom.Variant, 8, 0xB);
138+
}
139+
140+
private const byte Variant10xxValue = 0x80;
141+
private const ushort Version7Value = 0x7000;
142+
private const ushort VersionMask = 0xF000;
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private const byte Variant10xxMask = 0xC0;
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private Guid Next(DateTimeOffset timeStamp)
146+
{
147+
Span<byte> guidBytes = stackalloc byte[16];
148+
var succeeded = Guid.NewGuid().TryWriteBytes(guidBytes);
149+
var unixms = timeStamp.ToUnixTimeMilliseconds();
150+
Span<byte> counterBytes = stackalloc byte[sizeof(long)];
151+
MemoryMarshal.Write(counterBytes, in unixms);
152+
153+
if (!BitConverter.IsLittleEndian)
154+
{
155+
counterBytes.Reverse();
156+
}
157+
158+
//unix ts ms - 48 bits (6 bytes)
159+
guidBytes[00] = counterBytes[2];
160+
guidBytes[01] = counterBytes[3];
161+
guidBytes[02] = counterBytes[4];
162+
guidBytes[03] = counterBytes[5];
163+
guidBytes[04] = counterBytes[0];
164+
guidBytes[05] = counterBytes[1];
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166+
//UIDv7 version - first 4 bits (1/2 byte) of the next 16 bits (2 bytes)
167+
var _c = BitConverter.ToInt16(guidBytes.Slice(6, 2));
168+
_c = (short)((_c & ~VersionMask) | Version7Value);
169+
BitConverter.TryWriteBytes(guidBytes.Slice(6, 2), _c);
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171+
//2 bit variant
172+
//first 2 bits of the next 64 bits (8 bytes)
173+
guidBytes[8] = (byte)((guidBytes[8] & ~Variant10xxMask) | Variant10xxValue);
174+
return new Guid(guidBytes);
175+
}
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}
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}

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