Kit.Core/LibExternal/Npgsql/NpgsqlParameter`.cs

116 lines
3.7 KiB
C#

using System;
using System.Data;
using System.Threading;
using System.Threading.Tasks;
using Npgsql.Internal;
using Npgsql.TypeMapping;
using NpgsqlTypes;
using static Npgsql.Util.Statics;
namespace Npgsql;
/// <summary>
/// A generic version of <see cref="NpgsqlParameter"/> which provides more type safety and
/// avoids boxing of value types. Use <see cref="TypedValue"/> instead of <see cref="NpgsqlParameter.Value"/>.
/// </summary>
/// <typeparam name="T">The type of the value that will be stored in the parameter.</typeparam>
public sealed class NpgsqlParameter<T> : NpgsqlParameter
{
/// <summary>
/// Gets or sets the strongly-typed value of the parameter.
/// </summary>
public T? TypedValue { get; set; }
/// <summary>
/// Gets or sets the value of the parameter. This delegates to <see cref="TypedValue"/>.
/// </summary>
public override object? Value
{
get => TypedValue;
set => TypedValue = (T)value!;
}
#region Constructors
/// <summary>
/// Initializes a new instance of <see cref="NpgsqlParameter{T}" />.
/// </summary>
public NpgsqlParameter() {}
/// <summary>
/// Initializes a new instance of <see cref="NpgsqlParameter{T}" /> with a parameter name and value.
/// </summary>
public NpgsqlParameter(string parameterName, T value)
{
ParameterName = parameterName;
TypedValue = value;
}
/// <summary>
/// Initializes a new instance of <see cref="NpgsqlParameter{T}" /> with a parameter name and type.
/// </summary>
public NpgsqlParameter(string parameterName, NpgsqlDbType npgsqlDbType)
{
ParameterName = parameterName;
NpgsqlDbType = npgsqlDbType;
}
/// <summary>
/// Initializes a new instance of <see cref="NpgsqlParameter{T}" /> with a parameter name and type.
/// </summary>
public NpgsqlParameter(string parameterName, DbType dbType)
{
ParameterName = parameterName;
DbType = dbType;
}
#endregion Constructors
internal override void ResolveHandler(ConnectorTypeMapper typeMapper)
{
if (Handler is not null)
return;
// TODO: Better exceptions in case of cast failure etc.
if (_npgsqlDbType.HasValue)
Handler = typeMapper.ResolveByNpgsqlDbType(_npgsqlDbType.Value);
else if (_dataTypeName is not null)
Handler = typeMapper.ResolveByDataTypeName(_dataTypeName);
else
Handler = typeMapper.ResolveByValue(TypedValue);
}
internal override int ValidateAndGetLength()
{
if (TypedValue is null or DBNull)
return 0;
var lengthCache = LengthCache;
var len = Handler!.ValidateAndGetLength(TypedValue, ref lengthCache, this);
LengthCache = lengthCache;
return len;
}
internal override Task WriteWithLength(NpgsqlWriteBuffer buf, bool async, CancellationToken cancellationToken = default)
=> Handler!.WriteWithLength(TypedValue, buf, LengthCache, this, async, cancellationToken);
private protected override NpgsqlParameter CloneCore() =>
// use fields instead of properties
// to avoid auto-initializing something like type_info
new NpgsqlParameter<T>
{
_precision = _precision,
_scale = _scale,
_size = _size,
_npgsqlDbType = _npgsqlDbType,
_dataTypeName = _dataTypeName,
Direction = Direction,
IsNullable = IsNullable,
_name = _name,
TrimmedName = TrimmedName,
SourceColumn = SourceColumn,
SourceVersion = SourceVersion,
TypedValue = TypedValue,
SourceColumnNullMapping = SourceColumnNullMapping,
};
}