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Merged
davidkallesen merged 1 commit into from
Mar 14, 2026
Merged

feat(Mapping): support DateTimeOffset/DateTime, Uri/string conversions #13

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14 changes: 13 additions & 1 deletion src/Atc.SourceGenerators/Generators/Internal/MappingTypeAnalyzer.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -71,7 +71,8 @@ internal static bool IsBuiltInTypeConversion(

return IsStringToFromSystemTypeConversion(sourceTypeName, targetTypeName) ||
IsStringToFromUriConversion(sourceTypeName, targetTypeName) ||
IsStringToFromEnumConversion(sourceType, targetType, sourceTypeName, targetTypeName);
IsStringToFromEnumConversion(sourceType, targetType, sourceTypeName, targetTypeName) ||
IsDateTimeOffsetToFromDateTimeConversion(sourceTypeName, targetTypeName);
}

private static bool IsStringToFromSystemTypeConversion(
Expand Down Expand Up @@ -126,6 +127,17 @@ private static bool IsStringToFromUriConversion(
(normalizedSource == "System.Uri" && normalizedTarget == "string");
}

private static bool IsDateTimeOffsetToFromDateTimeConversion(
string sourceTypeName,
string targetTypeName)
{
var normalizedSource = sourceTypeName.TrimEnd('?');
var normalizedTarget = targetTypeName.TrimEnd('?');

return (normalizedSource == "System.DateTimeOffset" && normalizedTarget == "System.DateTime") ||
(normalizedSource == "System.DateTime" && normalizedTarget == "System.DateTimeOffset");
}

private static bool IsStringToFromEnumConversion(
ITypeSymbol sourceType,
ITypeSymbol targetType,
Expand Down
40 changes: 39 additions & 1 deletion src/Atc.SourceGenerators/Generators/MappingConfigurationGenerator.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -2518,12 +2518,50 @@ private static string GenerateBuiltInTypeConversion(
return $"bool.Parse({sourcePropertyAccess})";
}

// DateTimeOffset <-> DateTime conversions
if (normalizedSource == "System.DateTimeOffset" && normalizedTarget == "System.DateTime")
{
var sourceIsNullableValue = MappingTypeAnalyzer.IsNullableValueType(prop.SourceProperty.Type);
var targetIsNullableValue = MappingTypeAnalyzer.IsNullableValueType(prop.TargetProperty.Type);

if (sourceIsNullableValue && targetIsNullableValue)
{
return $"{sourcePropertyAccess}?.DateTime";
}

if (sourceIsNullableValue)
{
return $"{sourcePropertyAccess}!.Value.DateTime";
}

return $"{sourcePropertyAccess}.DateTime";
}

if (normalizedSource == "System.DateTime" && normalizedTarget == "System.DateTimeOffset")
{
var sourceIsNullableValue = MappingTypeAnalyzer.IsNullableValueType(prop.SourceProperty.Type);
var targetIsNullableValue = MappingTypeAnalyzer.IsNullableValueType(prop.TargetProperty.Type);

if (sourceIsNullableValue && targetIsNullableValue)
{
var varName = $"__{char.ToLowerInvariant(prop.SourceProperty.Name[0])}{prop.SourceProperty.Name.Substring(1)}";
return $"{sourcePropertyAccess} is {{ }} {varName} ? new global::System.DateTimeOffset({varName}) : null";
}

if (sourceIsNullableValue)
{
return $"new global::System.DateTimeOffset({sourcePropertyAccess}!.Value)";
}

return $"new global::System.DateTimeOffset({sourcePropertyAccess})";
}

// string <-> Uri conversions
if (normalizedSource == "string" && normalizedTarget == "System.Uri")
{
if (sourceIsNullableRef || targetIsNullableRef)
{
return $"{sourcePropertyAccess} is not null ? new global::System.Uri({sourcePropertyAccess}) : null";
return $"!string.IsNullOrEmpty({sourcePropertyAccess}) ? new global::System.Uri({sourcePropertyAccess}) : null";
}

return $"new global::System.Uri({sourcePropertyAccess})";
Expand Down
21 changes: 21 additions & 0 deletions src/Atc.SourceGenerators/Generators/ObjectMappingGenerator.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -760,6 +760,15 @@ private static bool IsBuiltInTypeConversion(
return true;
}

// DateTimeOffset <-> DateTime
var normalizedSource = sourceTypeName.TrimEnd('?');
var normalizedTarget = targetTypeName.TrimEnd('?');
if ((normalizedSource == "System.DateTimeOffset" && normalizedTarget == "System.DateTime") ||
(normalizedSource == "System.DateTime" && normalizedTarget == "System.DateTimeOffset"))
{
return true;
}

return false;
}

Expand Down Expand Up @@ -1917,6 +1926,18 @@ private static string GenerateBuiltInTypeConversion(
return $"bool.Parse({sourcePropertyAccess})";
}

// DateTimeOffset -> DateTime
if (sourceTypeName == "System.DateTimeOffset" && targetTypeName == "System.DateTime")
{
return $"{sourcePropertyAccess}.DateTime";
}

// DateTime -> DateTimeOffset
if (sourceTypeName == "System.DateTime" && targetTypeName == "System.DateTimeOffset")
{
return $"new global::System.DateTimeOffset({sourcePropertyAccess})";
}

// Fallback (should not reach here if IsBuiltInTypeConversion is correct)
return sourcePropertyAccess;
}
Expand Down
162 changes: 161 additions & 1 deletion ...ts/Generators/MappingConfiguration/MappingConfigurationGeneratorBuiltInConversionTests.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -119,7 +119,7 @@ public static partial class ItemMappings
var (diagnostics, output) = GetGeneratedOutput(source);

Assert.Empty(diagnostics);
Assert.Contains("is not null ? new global::System.Uri(source.Link) : null", output, StringComparison.Ordinal);
Assert.Contains("!string.IsNullOrEmpty(source.Link) ? new global::System.Uri(source.Link) : null", output, StringComparison.Ordinal);
}

[Fact]
Expand Down Expand Up @@ -644,4 +644,164 @@ public static partial class ItemMappings
Assert.Contains("Enum.TryParse<global::TargetNs.StatusType>(source.Status, out var __parsed)", output, StringComparison.Ordinal);
Assert.Contains("(double)source.Value", output, StringComparison.Ordinal);
}

[Fact]
public void Config_Should_Map_DateTimeOffset_To_DateTime()
{
const string source = """
using System;
using Atc.SourceGenerators.Annotations;

namespace SourceNs
{
public class Item
{
public DateTimeOffset Timestamp { get; set; }
}
}

namespace TargetNs
{
public class Item
{
public DateTime Timestamp { get; set; }
}
}

namespace Mappings
{
[MappingConfiguration]
public static partial class ItemMappings
{
public static partial TargetNs.Item MapToItem(this SourceNs.Item source);
}
}
""";

var (diagnostics, output) = GetGeneratedOutput(source);

Assert.Empty(diagnostics);
Assert.Contains("source.Timestamp.DateTime", output, StringComparison.Ordinal);
}

[Fact]
public void Config_Should_Map_DateTime_To_DateTimeOffset()
{
const string source = """
using System;
using Atc.SourceGenerators.Annotations;

namespace SourceNs
{
public class Item
{
public DateTime Timestamp { get; set; }
}
}

namespace TargetNs
{
public class Item
{
public DateTimeOffset Timestamp { get; set; }
}
}

namespace Mappings
{
[MappingConfiguration]
public static partial class ItemMappings
{
public static partial TargetNs.Item MapToItem(this SourceNs.Item source);
}
}
""";

var (diagnostics, output) = GetGeneratedOutput(source);

Assert.Empty(diagnostics);
Assert.Contains("new global::System.DateTimeOffset(source.Timestamp)", output, StringComparison.Ordinal);
}

[Fact]
public void Config_Should_Map_Nullable_DateTimeOffset_To_Nullable_DateTime()
{
const string source = """
using System;
using Atc.SourceGenerators.Annotations;

#nullable enable

namespace SourceNs
{
public class Item
{
public DateTimeOffset? Timestamp { get; set; }
}
}

namespace TargetNs
{
public class Item
{
public DateTime? Timestamp { get; set; }
}
}

namespace Mappings
{
[MappingConfiguration]
public static partial class ItemMappings
{
public static partial TargetNs.Item MapToItem(this SourceNs.Item source);
}
}
""";

var (diagnostics, output) = GetGeneratedOutput(source);

Assert.Empty(diagnostics);
Assert.Contains("source.Timestamp?.DateTime", output, StringComparison.Ordinal);
}

[Fact]
public void Config_Should_Map_Nullable_DateTime_To_Nullable_DateTimeOffset()
{
const string source = """
using System;
using Atc.SourceGenerators.Annotations;

#nullable enable

namespace SourceNs
{
public class Item
{
public DateTime? Timestamp { get; set; }
}
}

namespace TargetNs
{
public class Item
{
public DateTimeOffset? Timestamp { get; set; }
}
}

namespace Mappings
{
[MappingConfiguration]
public static partial class ItemMappings
{
public static partial TargetNs.Item MapToItem(this SourceNs.Item source);
}
}
""";

var (diagnostics, output) = GetGeneratedOutput(source);

Assert.Empty(diagnostics);
Assert.Contains("is { } __timestamp ? new global::System.DateTimeOffset(__timestamp) : null", output, StringComparison.Ordinal);
}
}