public override void Emit(Type sourceType, Type targetType, CompilationContext context)
{
if (sourceType == typeof(string))
{
return;
}
if (sourceType.IsNullable())
{
var target = context.DeclareLocal(targetType);
var local = context.DeclareLocal(sourceType);
context.Emit(OpCodes.Stloc, local);
context.EmitNullableExpression(local, ctx =>
{
ctx.EmitCast(typeof(object));
ctx.EmitCall(_toStringMethod);
ctx.Emit(OpCodes.Stloc, target);
}, ctx =>
{
ctx.EmitDefault(typeof(string));
ctx.Emit(OpCodes.Stloc, target);
});
context.Emit(OpCodes.Ldloc, target);
}
#if NETSTANDARD
else if (sourceType.GetTypeInfo().IsValueType)
#else
else if (sourceType.IsValueType)
#endif
{
context.EmitCast(typeof(object));
context.EmitCall(_toStringMethod);
}
else
{
var target = context.DeclareLocal(targetType);
var local = context.DeclareLocal(sourceType);
context.Emit(OpCodes.Stloc, local);
context.EmitNullableExpression(local, ctx =>
{
ctx.EmitCast(typeof(object));
ctx.EmitCall(_toStringMethod);
ctx.Emit(OpCodes.Stloc, target);
}, ctx =>
{
context.Emit(OpCodes.Ldnull);
ctx.Emit(OpCodes.Stloc, target);
});
context.Emit(OpCodes.Ldloc, target);
}
context.CurrentType = targetType;
}
private bool EmitNullableSource(CompilationContext context, Type sourceType, Type targetType)
{
#if NETSTANDARD
var reflectingSourceType = sourceType.GetTypeInfo();
#else
var reflectingSourceType = sourceType;
#endif
var sourceUnderlingType = reflectingSourceType.GetGenericArguments()[0];
var converter = GetConvertEmitter(sourceUnderlingType, targetType);
if (converter != null)
{
var target = context.DeclareLocal(targetType);
var local = context.DeclareLocal(sourceType);
context.Emit(OpCodes.Stloc, local);
context.EmitNullableExpression(local, ctx =>
{
converter(ctx);
ctx.Emit(OpCodes.Stloc, target);
}, ctx =>
{
context.EmitDefault(targetType);
context.Emit(OpCodes.Stloc, target);
});
context.Emit(OpCodes.Ldloc, target);
return(true);
}
return(false);
}
private bool EmitBothNullable(CompilationContext context, Type sourceType, Type targetType)
{
#if NETSTANDARD
var reflectingTargetType = targetType.GetTypeInfo();
var reflectingSourceType = sourceType.GetTypeInfo();
#else
var reflectingTargetType = targetType;
var reflectingSourceType = sourceType;
#endif
var sourceUnderlingType = reflectingSourceType.GetGenericArguments()[0];
var targetUnderlingyType = reflectingTargetType.GetGenericArguments()[0];
// When the source and target member are the same nullbale type
if (targetUnderlingyType == sourceUnderlingType)
{
return(true);
}
// When the source and target member are not the same nullable type,
// But their underlying type can be implicitly or explicitly converted.
var converter = GetConvertEmitter(sourceUnderlingType, targetUnderlingyType);
if (converter != null)
{
var target = context.DeclareLocal(targetType);
var local = context.DeclareLocal(sourceType);
context.Emit(OpCodes.Stloc, local);
context.EmitNullableExpression(local, ctx =>
{
converter(ctx);
ctx.Emit(OpCodes.Newobj, reflectingTargetType.GetConstructors()[0]);
ctx.Emit(OpCodes.Stloc, target);
}, ctx =>
{
ctx.EmitDefault(targetType);
ctx.Emit(OpCodes.Stloc, target);
});
context.Emit(OpCodes.Ldloc, target);
return(true);
}
return(false);
}
