Artifact
75c68d740112cc557032a3534ece4ddad58d455a:
/********************************************************
* ADO.NET 2.0 Data Provider for SQLite Version 3.X
* Written by Robert Simpson (robert@blackcastlesoft.com)
*
* Released to the public domain, use at your own risk!
********************************************************/
namespace System.Data.SQLite
{
using System;
/// <summary>
/// A simple custom attribute to enable us to easily find user-defined functions in
/// the loaded assemblies and initialize them in SQLite as connections are made.
/// </summary>
[AttributeUsage(AttributeTargets.Class, Inherited = false, AllowMultiple = true)]
public sealed class SQLiteFunctionAttribute : Attribute
{
private string _name;
private int _argumentCount;
private FunctionType _functionType;
private Type _instanceType;
private Delegate _callback1;
private Delegate _callback2;
/// <summary>
/// Default constructor, initializes the internal variables for the function.
/// </summary>
public SQLiteFunctionAttribute()
: this(null, -1, FunctionType.Scalar)
{
// do nothing.
}
/// <summary>
/// Constructs an instance of this class. This sets the initial
/// <see cref="InstanceType" />, <see cref="Callback1" />, and
/// <see cref="Callback2" /> properties to null.
/// </summary>
/// <param name="name">
/// The name of the function, as seen by the SQLite core library.
/// </param>
/// <param name="argumentCount">
/// The number of arguments that the function will accept.
/// </param>
/// <param name="functionType">
/// The type of function being declared. This will either be Scalar,
/// Aggregate, or Collation.
/// </param>
public SQLiteFunctionAttribute(
string name,
int argumentCount,
FunctionType functionType
)
{
_name = name;
_argumentCount = argumentCount;
_functionType = functionType;
_instanceType = null;
_callback1 = null;
_callback2 = null;
}
/// <summary>
/// The function's name as it will be used in SQLite command text.
/// </summary>
public string Name
{
get { return _name; }
set { _name = value; }
}
/// <summary>
/// The number of arguments this function expects. -1 if the number of arguments is variable.
/// </summary>
public int Arguments
{
get { return _argumentCount; }
set { _argumentCount = value; }
}
/// <summary>
/// The type of function this implementation will be.
/// </summary>
public FunctionType FuncType
{
get { return _functionType; }
set { _functionType = value; }
}
/// <summary>
/// The <see cref="System.Type" /> object instance that describes the class
/// containing the implementation for the associated function. The value of
/// this property will not be used if either the <see cref="Callback1" /> or
/// <see cref="Callback2" /> property values are set to non-null.
/// </summary>
internal Type InstanceType
{
get { return _instanceType; }
set { _instanceType = value; }
}
/// <summary>
/// The <see cref="Delegate" /> that refers to the implementation for the
/// associated function. If this property value is set to non-null, it will
/// be used instead of the <see cref="InstanceType" /> property value.
/// </summary>
internal Delegate Callback1
{
get { return _callback1; }
set { _callback1 = value; }
}
/// <summary>
/// The <see cref="Delegate" /> that refers to the implementation for the
/// associated function. If this property value is set to non-null, it will
/// be used instead of the <see cref="InstanceType" /> property value.
/// </summary>
internal Delegate Callback2
{
get { return _callback2; }
set { _callback2 = value; }
}
}
}