/********************************************************
* ADO.NET 2.0 Data Provider for SQLite Version 3.X
* Written by Joe Mistachkin (joe@mistachkin.com)
*
* Released to the public domain, use at your own risk!
********************************************************/
using System.Globalization;
#region Non-Generic Classes
namespace System.Data.SQLite
{
#region SQLiteModuleCommon Class
/// <summary>
/// This class contains some virtual methods that may be useful for other
/// virtual table classes. It specifically does NOT implement any of the
/// <see cref="ISQLiteManagedModule" /> interface methods.
/// </summary>
public class SQLiteModuleCommon : SQLiteModuleNoop /* NOT SEALED */
{
#region Private Constants
/// <summary>
/// The CREATE TABLE statement used to declare the schema for the
/// virtual table.
/// </summary>
private static readonly string declareSql =
HelperMethods.StringFormat(
CultureInfo.InvariantCulture, "CREATE TABLE {0}(x);",
typeof(SQLiteModuleCommon).Name);
#endregion
///////////////////////////////////////////////////////////////////////
#region Private Data
/// <summary>
/// Non-zero if different object instances with the same value should
/// generate different row identifiers, where applicable. This has no
/// effect on the .NET Compact Framework.
/// </summary>
private bool objectIdentity;
#endregion
///////////////////////////////////////////////////////////////////////
#region Public Constructors
/// <summary>
/// Constructs an instance of this class.
/// </summary>
/// <param name="name">
/// The name of the module. This parameter cannot be null.
/// </param>
public SQLiteModuleCommon(
string name
)
: this(name, false)
{
// do nothing.
}
///////////////////////////////////////////////////////////////////////
/// <summary>
/// Constructs an instance of this class.
/// </summary>
/// <param name="name">
/// The name of the module. This parameter cannot be null.
/// </param>
/// <param name="objectIdentity">
/// Non-zero if different object instances with the same value should
/// generate different row identifiers, where applicable. This
/// parameter has no effect on the .NET Compact Framework.
/// </param>
public SQLiteModuleCommon(
string name,
bool objectIdentity
)
: base(name)
{
this.objectIdentity = objectIdentity;
}
#endregion
///////////////////////////////////////////////////////////////////////
#region Protected Methods
/// <summary>
/// Determines the SQL statement used to declare the virtual table.
/// This method should be overridden in derived classes if they require
/// a custom virtual table schema.
/// </summary>
/// <returns>
/// The SQL statement used to declare the virtual table -OR- null if it
/// cannot be determined.
/// </returns>
protected virtual string GetSqlForDeclareTable()
{
return declareSql;
}
///////////////////////////////////////////////////////////////////////
/// <summary>
/// Sets the table error message to one that indicates the virtual
/// table cursor is of the wrong type.
/// </summary>
/// <param name="cursor">
/// The <see cref="SQLiteVirtualTableCursor" /> object instance.
/// </param>
/// <param name="type">
/// The <see cref="Type" /> that the virtual table cursor should be.
/// </param>
/// <returns>
/// The value of <see cref="SQLiteErrorCode.Error" />.
/// </returns>
protected virtual SQLiteErrorCode CursorTypeMismatchError(
SQLiteVirtualTableCursor cursor,
Type type
)
{
if (type != null)
{
SetCursorError(cursor, HelperMethods.StringFormat(
CultureInfo.CurrentCulture, "not a \"{0}\" cursor",
type));
}
else
{
SetCursorError(cursor, "cursor type mismatch");
}
return SQLiteErrorCode.Error;
}
///////////////////////////////////////////////////////////////////////
/// <summary>
/// Determines the string to return as the column value for the object
/// instance value.
/// </summary>
/// <param name="cursor">
/// The <see cref="SQLiteVirtualTableCursor" /> object instance
/// associated with the previously opened virtual table cursor to be
/// used.
/// </param>
/// <param name="value">
/// The object instance to return a string representation for.
/// </param>
/// <returns>
/// The string representation of the specified object instance or null
/// upon failure.
/// </returns>
protected virtual string GetStringFromObject(
SQLiteVirtualTableCursor cursor,
object value
)
{
if (value == null)
return null;
if (value is string)
return (string)value;
return value.ToString();
}
///////////////////////////////////////////////////////////////////////
/// <summary>
/// Constructs an <see cref="Int64" /> unique row identifier from two
/// <see cref="Int32" /> values. The first <see cref="Int32" /> value
/// must contain the row sequence number for the current row and the
/// second value must contain the hash code of the key column value
/// for the current row.
/// </summary>
/// <param name="rowIndex">
/// The integer row sequence number for the current row.
/// </param>
/// <param name="hashCode">
/// The hash code of the key column value for the current row.
/// </param>
/// <returns>
/// The unique row identifier or zero upon failure.
/// </returns>
protected virtual long MakeRowId(
int rowIndex,
int hashCode
)
{
long result = rowIndex;
result <<= 32; /* typeof(int) bits */
result |= (long)(uint)hashCode;
return result;
}
///////////////////////////////////////////////////////////////////////
/// <summary>
/// Determines the unique row identifier for the current row.
/// </summary>
/// <param name="cursor">
/// The <see cref="SQLiteVirtualTableCursor" /> object instance
/// associated with the previously opened virtual table cursor to be
/// used.
/// </param>
/// <param name="value">
/// The object instance to return a unique row identifier for.
/// </param>
/// <returns>
/// The unique row identifier or zero upon failure.
/// </returns>
protected virtual long GetRowIdFromObject(
SQLiteVirtualTableCursor cursor,
object value
)
{
int rowIndex = (cursor != null) ? cursor.GetRowIndex() : 0;
int hashCode = SQLiteMarshal.GetHashCode(value, objectIdentity);
return MakeRowId(rowIndex, hashCode);
}
#endregion
///////////////////////////////////////////////////////////////////////
#region IDisposable "Pattern" Members
private bool disposed;
/// <summary>
/// Throws an <see cref="ObjectDisposedException" /> if this object
/// instance has been disposed.
/// </summary>
private void CheckDisposed() /* throw */
{
#if THROW_ON_DISPOSED
if (disposed)
{
throw new ObjectDisposedException(
typeof(SQLiteModuleCommon).Name);
}
#endif
}
///////////////////////////////////////////////////////////////////////
/// <summary>
/// Disposes of this object instance.
/// </summary>
/// <param name="disposing">
/// Non-zero if this method is being called from the
/// <see cref="IDisposable.Dispose" /> method. Zero if this method is
/// being called from the finalizer.
/// </param>
protected override void Dispose(bool disposing)
{
try
{
if (!disposed)
{
//if (disposing)
//{
// ////////////////////////////////////
// // dispose managed resources here...
// ////////////////////////////////////
//}
//////////////////////////////////////
// release unmanaged resources here...
//////////////////////////////////////
}
}
finally
{
base.Dispose(disposing);
//
// NOTE: Everything should be fully disposed at this point.
//
disposed = true;
}
}
#endregion
}
#endregion
}
#endregion
