SQLiteModuleNoop.cs

/********************************************************
 * 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.Collections.Generic;

namespace System.Data.SQLite
{
    /// <summary>
    /// This class implements a virtual table module that does nothing by
    /// providing "empty" implementations for all of the
    /// <see cref="ISQLiteManagedModule" /> interface methods.  The result
    /// codes returned by these "empty" method implementations may be
    /// controlled on a per-method basis by using and/or overriding the
    /// <see cref="GetDefaultResultCode" />,
    /// <see cref="ResultCodeToEofResult" />,
    /// <see cref="ResultCodeToFindFunctionResult" />,
    /// <see cref="GetMethodResultCode" />, and
    /// <see cref="SetMethodResultCode" /> methods from within derived classes.
    /// </summary>
    public class SQLiteModuleNoop : SQLiteModule /* NOT SEALED */
    {
        #region Private Data
        /// <summary>
        /// This field is used to store the <see cref="SQLiteErrorCode" />
        /// values to return, on a per-method basis, for all methods that are
        /// part of the <see cref="ISQLiteManagedModule" /> interface.
        /// </summary>
        private Dictionary<string, SQLiteErrorCode> resultCodes;
        #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 SQLiteModuleNoop(
            string name
            )
            : base(name)
        {
            resultCodes = new Dictionary<string, SQLiteErrorCode>();
        }
        #endregion

        ///////////////////////////////////////////////////////////////////////

        #region Protected Methods
        /// <summary>
        /// Determines the default <see cref="SQLiteErrorCode" /> value to be
        /// returned by methods of the <see cref="ISQLiteManagedModule" />
        /// interface that lack an overridden implementation in all classes
        /// derived from the <see cref="SQLiteModuleNoop" /> class.
        /// </summary>
        /// <returns>
        /// The <see cref="SQLiteErrorCode" /> value that should be returned
        /// by all <see cref="ISQLiteManagedModule" /> interface methods unless
        /// a more specific result code has been set for that interface method.
        /// </returns>
        protected virtual SQLiteErrorCode GetDefaultResultCode()
        {
            return SQLiteErrorCode.Ok;
        }

        ///////////////////////////////////////////////////////////////////////

        /// <summary>
        /// Converts a <see cref="SQLiteErrorCode" /> value into a boolean
        /// return value for use with the
        /// <see cref="ISQLiteManagedModule.Eof" /> method.
        /// </summary>
        /// <param name="resultCode">
        /// The <see cref="SQLiteErrorCode" /> value to convert.
        /// </param>
        /// <returns>
        /// The <see cref="Boolean" /> value.
        /// </returns>
        protected virtual bool ResultCodeToEofResult(
            SQLiteErrorCode resultCode
            )
        {
            return (resultCode == SQLiteErrorCode.Ok) ? false : true;
        }

        ///////////////////////////////////////////////////////////////////////

        /// <summary>
        /// Converts a <see cref="SQLiteErrorCode" /> value into a boolean
        /// return value for use with the
        /// <see cref="ISQLiteManagedModule.FindFunction" /> method.
        /// </summary>
        /// <param name="resultCode">
        /// The <see cref="SQLiteErrorCode" /> value to convert.
        /// </param>
        /// <returns>
        /// The <see cref="Boolean" /> value.
        /// </returns>
        protected virtual bool ResultCodeToFindFunctionResult(
            SQLiteErrorCode resultCode
            )
        {
            return (resultCode == SQLiteErrorCode.Ok) ? true : false;
        }

        ///////////////////////////////////////////////////////////////////////

        /// <summary>
        /// Determines the <see cref="SQLiteErrorCode" /> value that should be
        /// returned by the specified <see cref="ISQLiteManagedModule" />
        /// interface method if it lack an overridden implementation.  If no
        /// specific <see cref="SQLiteErrorCode" /> value is available (or set)
        /// for the specified method, the <see cref="SQLiteErrorCode" /> value
        /// returned by the <see cref="GetDefaultResultCode" /> method will be
        /// returned instead.
        /// </summary>
        /// <param name="methodName">
        /// The name of the method.  Currently, this method must be part of
        /// the <see cref="ISQLiteManagedModule" /> interface.
        /// </param>
        /// <returns>
        /// The <see cref="SQLiteErrorCode" /> value that should be returned
        /// by the <see cref="ISQLiteManagedModule" /> interface method.
        /// </returns>
        protected virtual SQLiteErrorCode GetMethodResultCode(
            string methodName
            )
        {
            if ((methodName == null) || (resultCodes == null))
                return GetDefaultResultCode();

            SQLiteErrorCode resultCode;

            if ((resultCodes != null) &&
                resultCodes.TryGetValue(methodName, out resultCode))
            {
                return resultCode;
            }

            return GetDefaultResultCode();
        }

        ///////////////////////////////////////////////////////////////////////

        /// <summary>
        /// Sets the <see cref="SQLiteErrorCode" /> value that should be
        /// returned by the specified <see cref="ISQLiteManagedModule" />
        /// interface method if it lack an overridden implementation.
        /// </summary>
        /// <param name="methodName">
        /// The name of the method.  Currently, this method must be part of
        /// the <see cref="ISQLiteManagedModule" /> interface.
        /// </param>
        /// <param name="resultCode">
        /// The <see cref="SQLiteErrorCode" /> value that should be returned
        /// by the <see cref="ISQLiteManagedModule" /> interface method.
        /// </param>
        /// <returns>
        /// Non-zero upon success.
        /// </returns>
        protected virtual bool SetMethodResultCode(
            string methodName,
            SQLiteErrorCode resultCode
            )
        {
            if ((methodName == null) || (resultCodes == null))
                return false;

            resultCodes[methodName] = resultCode;
            return true;
        }
        #endregion

        ///////////////////////////////////////////////////////////////////////

        #region ISQLiteManagedModule Members
        /// <summary>
        /// See the <see cref="ISQLiteManagedModule.Create" /> method.
        /// </summary>
        /// <param name="connection">
        /// See the <see cref="ISQLiteManagedModule.Create" /> method.
        /// </param>
        /// <param name="pClientData">
        /// See the <see cref="ISQLiteManagedModule.Create" /> method.
        /// </param>
        /// <param name="arguments">
        /// See the <see cref="ISQLiteManagedModule.Create" /> method.
        /// </param>
        /// <param name="table">
        /// See the <see cref="ISQLiteManagedModule.Create" /> method.
        /// </param>
        /// <param name="error">
        /// See the <see cref="ISQLiteManagedModule.Create" /> method.
        /// </param>
        /// <returns>
        /// See the <see cref="ISQLiteManagedModule.Create" /> method.
        /// </returns>
        public override SQLiteErrorCode Create(
            SQLiteConnection connection,
            IntPtr pClientData,
            string[] arguments,
            ref SQLiteVirtualTable table,
            ref string error
            )
        {
            CheckDisposed();

            return GetMethodResultCode("Create");
        }

        ///////////////////////////////////////////////////////////////////////

        /// <summary>
        /// See the <see cref="ISQLiteManagedModule.Connect" /> method.
        /// </summary>
        /// <param name="connection">
        /// See the <see cref="ISQLiteManagedModule.Connect" /> method.
        /// </param>
        /// <param name="pClientData">
        /// See the <see cref="ISQLiteManagedModule.Connect" /> method.
        /// </param>
        /// <param name="arguments">
        /// See the <see cref="ISQLiteManagedModule.Connect" /> method.
        /// </param>
        /// <param name="table">
        /// See the <see cref="ISQLiteManagedModule.Connect" /> method.
        /// </param>
        /// <param name="error">
        /// See the <see cref="ISQLiteManagedModule.Connect" /> method.
        /// </param>
        /// <returns>
        /// See the <see cref="ISQLiteManagedModule.Connect" /> method.
        /// </returns>
        public override SQLiteErrorCode Connect(
            SQLiteConnection connection,
            IntPtr pClientData,
            string[] arguments,
            ref SQLiteVirtualTable table,
            ref string error
            )
        {
            CheckDisposed();

            return GetMethodResultCode("Connect");
        }

        ///////////////////////////////////////////////////////////////////////

        /// <summary>
        /// See the <see cref="ISQLiteManagedModule.BestIndex" /> method.
        /// </summary>
        /// <param name="table">
        /// See the <see cref="ISQLiteManagedModule.BestIndex" /> method.
        /// </param>
        /// <param name="index">
        /// See the <see cref="ISQLiteManagedModule.BestIndex" /> method.
        /// </param>
        /// <returns>
        /// See the <see cref="ISQLiteManagedModule.BestIndex" /> method.
        /// </returns>
        public override SQLiteErrorCode BestIndex(
            SQLiteVirtualTable table,
            SQLiteIndex index
            )
        {
            CheckDisposed();

            return GetMethodResultCode("BestIndex");
        }

        ///////////////////////////////////////////////////////////////////////

        /// <summary>
        /// See the <see cref="ISQLiteManagedModule.Disconnect" /> method.
        /// </summary>
        /// <param name="table">
        /// See the <see cref="ISQLiteManagedModule.Disconnect" /> method.
        /// </param>
        /// <returns>
        /// See the <see cref="ISQLiteManagedModule.Disconnect" /> method.
        /// </returns>
        public override SQLiteErrorCode Disconnect(
            SQLiteVirtualTable table
            )
        {
            CheckDisposed();

            return GetMethodResultCode("Disconnect");
        }

        ///////////////////////////////////////////////////////////////////////

        /// <summary>
        /// See the <see cref="ISQLiteManagedModule.Destroy" /> method.
        /// </summary>
        /// <param name="table">
        /// See the <see cref="ISQLiteManagedModule.Destroy" /> method.
        /// </param>
        /// <returns>
        /// See the <see cref="ISQLiteManagedModule.Destroy" /> method.
        /// </returns>
        public override SQLiteErrorCode Destroy(
            SQLiteVirtualTable table
            )
        {
            CheckDisposed();

            return GetMethodResultCode("Destroy");
        }

        ///////////////////////////////////////////////////////////////////////

        /// <summary>
        /// See the <see cref="ISQLiteManagedModule.Open" /> method.
        /// </summary>
        /// <param name="table">
        /// See the <see cref="ISQLiteManagedModule.Open" /> method.
        /// </param>
        /// <param name="cursor">
        /// See the <see cref="ISQLiteManagedModule.Open" /> method.
        /// </param>
        /// <returns>
        /// See the <see cref="ISQLiteManagedModule.Open" /> method.
        /// </returns>
        public override SQLiteErrorCode Open(
            SQLiteVirtualTable table,
            ref SQLiteVirtualTableCursor cursor
            )
        {
            CheckDisposed();

            return GetMethodResultCode("Open");
        }

        ///////////////////////////////////////////////////////////////////////

        /// <summary>
        /// See the <see cref="ISQLiteManagedModule.Close" /> method.
        /// </summary>
        /// <param name="cursor">
        /// See the <see cref="ISQLiteManagedModule.Close" /> method.
        /// </param>
        /// <returns>
        /// See the <see cref="ISQLiteManagedModule.Close" /> method.
        /// </returns>
        public override SQLiteErrorCode Close(
            SQLiteVirtualTableCursor cursor
            )
        {
            CheckDisposed();

            return GetMethodResultCode("Close");
        }

        ///////////////////////////////////////////////////////////////////////

        /// <summary>
        /// See the <see cref="ISQLiteManagedModule.Filter" /> method.
        /// </summary>
        /// <param name="cursor">
        /// See the <see cref="ISQLiteManagedModule.Filter" /> method.
        /// </param>
        /// <param name="indexNumber">
        /// See the <see cref="ISQLiteManagedModule.Filter" /> method.
        /// </param>
        /// <param name="indexString">
        /// See the <see cref="ISQLiteManagedModule.Filter" /> method.
        /// </param>
        /// <param name="values">
        /// See the <see cref="ISQLiteManagedModule.Filter" /> method.
        /// </param>
        /// <returns>
        /// See the <see cref="ISQLiteManagedModule.Filter" /> method.
        /// </returns>
        public override SQLiteErrorCode Filter(
            SQLiteVirtualTableCursor cursor,
            int indexNumber,
            string indexString,
            SQLiteValue[] values
            )
        {
            CheckDisposed();

            return GetMethodResultCode("Filter");
        }

        ///////////////////////////////////////////////////////////////////////

        /// <summary>
        /// See the <see cref="ISQLiteManagedModule.Next" /> method.
        /// </summary>
        /// <param name="cursor">
        /// See the <see cref="ISQLiteManagedModule.Next" /> method.
        /// </param>
        /// <returns>
        /// See the <see cref="ISQLiteManagedModule.Next" /> method.
        /// </returns>
        public override SQLiteErrorCode Next(
            SQLiteVirtualTableCursor cursor
            )
        {
            CheckDisposed();

            return GetMethodResultCode("Next");
        }

        ///////////////////////////////////////////////////////////////////////

        /// <summary>
        /// See the <see cref="ISQLiteManagedModule.Eof" /> method.
        /// </summary>
        /// <param name="cursor">
        /// See the <see cref="ISQLiteManagedModule.Eof" /> method.
        /// </param>
        /// <returns>
        /// See the <see cref="ISQLiteManagedModule.Eof" /> method.
        /// </returns>
        public override bool Eof(
            SQLiteVirtualTableCursor cursor
            )
        {
            CheckDisposed();

            return ResultCodeToEofResult(GetMethodResultCode("Eof"));
        }

        ///////////////////////////////////////////////////////////////////////

        /// <summary>
        /// See the <see cref="ISQLiteManagedModule.Column" /> method.
        /// </summary>
        /// <param name="cursor">
        /// See the <see cref="ISQLiteManagedModule.Column" /> method.
        /// </param>
        /// <param name="context">
        /// See the <see cref="ISQLiteManagedModule.Column" /> method.
        /// </param>
        /// <param name="index">
        /// See the <see cref="ISQLiteManagedModule.Column" /> method.
        /// </param>
        /// <returns>
        /// See the <see cref="ISQLiteManagedModule.Column" /> method.
        /// </returns>
        public override SQLiteErrorCode Column(
            SQLiteVirtualTableCursor cursor,
            SQLiteContext context,
            int index
            )
        {
            CheckDisposed();

            return GetMethodResultCode("Column");
        }

        ///////////////////////////////////////////////////////////////////////

        /// <summary>
        /// See the <see cref="ISQLiteManagedModule.RowId" /> method.
        /// </summary>
        /// <param name="cursor">
        /// See the <see cref="ISQLiteManagedModule.RowId" /> method.
        /// </param>
        /// <param name="rowId">
        /// See the <see cref="ISQLiteManagedModule.RowId" /> method.
        /// </param>
        /// <returns>
        /// See the <see cref="ISQLiteManagedModule.RowId" /> method.
        /// </returns>
        public override SQLiteErrorCode RowId(
            SQLiteVirtualTableCursor cursor,
            ref long rowId
            )
        {
            CheckDisposed();

            return GetMethodResultCode("RowId");
        }

        ///////////////////////////////////////////////////////////////////////

        /// <summary>
        /// See the <see cref="ISQLiteManagedModule.Update" /> method.
        /// </summary>
        /// <param name="table">
        /// See the <see cref="ISQLiteManagedModule.Update" /> method.
        /// </param>
        /// <param name="values">
        /// See the <see cref="ISQLiteManagedModule.Update" /> method.
        /// </param>
        /// <param name="rowId">
        /// See the <see cref="ISQLiteManagedModule.Update" /> method.
        /// </param>
        /// <returns>
        /// See the <see cref="ISQLiteManagedModule.Update" /> method.
        /// </returns>
        public override SQLiteErrorCode Update(
            SQLiteVirtualTable table,
            SQLiteValue[] values,
            ref long rowId
            )
        {
            CheckDisposed();

            return GetMethodResultCode("Update");
        }

        ///////////////////////////////////////////////////////////////////////

        /// <summary>
        /// See the <see cref="ISQLiteManagedModule.Begin" /> method.
        /// </summary>
        /// <param name="table">
        /// See the <see cref="ISQLiteManagedModule.Begin" /> method.
        /// </param>
        /// <returns>
        /// See the <see cref="ISQLiteManagedModule.Begin" /> method.
        /// </returns>
        public override SQLiteErrorCode Begin(
            SQLiteVirtualTable table
            )
        {
            CheckDisposed();

            return GetMethodResultCode("Begin");
        }

        ///////////////////////////////////////////////////////////////////////

        /// <summary>
        /// See the <see cref="ISQLiteManagedModule.Sync" /> method.
        /// </summary>
        /// <param name="table">
        /// See the <see cref="ISQLiteManagedModule.Sync" /> method.
        /// </param>
        /// <returns>
        /// See the <see cref="ISQLiteManagedModule.Sync" /> method.
        /// </returns>
        public override SQLiteErrorCode Sync(
            SQLiteVirtualTable table
            )
        {
            CheckDisposed();

            return GetMethodResultCode("Sync");
        }

        ///////////////////////////////////////////////////////////////////////

        /// <summary>
        /// See the <see cref="ISQLiteManagedModule.Commit" /> method.
        /// </summary>
        /// <param name="table">
        /// See the <see cref="ISQLiteManagedModule.Commit" /> method.
        /// </param>
        /// <returns>
        /// See the <see cref="ISQLiteManagedModule.Commit" /> method.
        /// </returns>
        public override SQLiteErrorCode Commit(
            SQLiteVirtualTable table
            )
        {
            CheckDisposed();

            return GetMethodResultCode("Commit");
        }

        ///////////////////////////////////////////////////////////////////////

        /// <summary>
        /// See the <see cref="ISQLiteManagedModule.Rollback" /> method.
        /// </summary>
        /// <param name="table">
        /// See the <see cref="ISQLiteManagedModule.Rollback" /> method.
        /// </param>
        /// <returns>
        /// See the <see cref="ISQLiteManagedModule.Rollback" /> method.
        /// </returns>
        public override SQLiteErrorCode Rollback(
            SQLiteVirtualTable table
            )
        {
            CheckDisposed();

            return GetMethodResultCode("Rollback");
        }

        ///////////////////////////////////////////////////////////////////////

        /// <summary>
        /// See the <see cref="ISQLiteManagedModule.FindFunction" /> method.
        /// </summary>
        /// <param name="table">
        /// See the <see cref="ISQLiteManagedModule.FindFunction" /> method.
        /// </param>
        /// <param name="argumentCount">
        /// See the <see cref="ISQLiteManagedModule.FindFunction" /> method.
        /// </param>
        /// <param name="name">
        /// See the <see cref="ISQLiteManagedModule.FindFunction" /> method.
        /// </param>
        /// <param name="function">
        /// See the <see cref="ISQLiteManagedModule.FindFunction" /> method.
        /// </param>
        /// <param name="pClientData">
        /// See the <see cref="ISQLiteManagedModule.FindFunction" /> method.
        /// </param>
        /// <returns>
        /// See the <see cref="ISQLiteManagedModule.FindFunction" /> method.
        /// </returns>
        public override bool FindFunction(
            SQLiteVirtualTable table,
            int argumentCount,
            string name,
            ref SQLiteFunction function,
            ref IntPtr pClientData
            )
        {
            CheckDisposed();

            return ResultCodeToFindFunctionResult(GetMethodResultCode(
                "FindFunction"));
        }

        ///////////////////////////////////////////////////////////////////////

        /// <summary>
        /// See the <see cref="ISQLiteManagedModule.Rename" /> method.
        /// </summary>
        /// <param name="table">
        /// See the <see cref="ISQLiteManagedModule.Rename" /> method.
        /// </param>
        /// <param name="newName">
        /// See the <see cref="ISQLiteManagedModule.Rename" /> method.
        /// </param>
        /// <returns>
        /// See the <see cref="ISQLiteManagedModule.Rename" /> method.
        /// </returns>
        public override SQLiteErrorCode Rename(
            SQLiteVirtualTable table,
            string newName
            )
        {
            CheckDisposed();

            return GetMethodResultCode("Rename");
        }

        ///////////////////////////////////////////////////////////////////////

        /// <summary>
        /// See the <see cref="ISQLiteManagedModule.Savepoint" /> method.
        /// </summary>
        /// <param name="table">
        /// See the <see cref="ISQLiteManagedModule.Savepoint" /> method.
        /// </param>
        /// <param name="savepoint">
        /// See the <see cref="ISQLiteManagedModule.Savepoint" /> method.
        /// </param>
        /// <returns>
        /// See the <see cref="ISQLiteManagedModule.Savepoint" /> method.
        /// </returns>
        public override SQLiteErrorCode Savepoint(
            SQLiteVirtualTable table,
            int savepoint
            )
        {
            CheckDisposed();

            return GetMethodResultCode("Savepoint");
        }

        ///////////////////////////////////////////////////////////////////////

        /// <summary>
        /// See the <see cref="ISQLiteManagedModule.Release" /> method.
        /// </summary>
        /// <param name="table">
        /// See the <see cref="ISQLiteManagedModule.Release" /> method.
        /// </param>
        /// <param name="savepoint">
        /// See the <see cref="ISQLiteManagedModule.Release" /> method.
        /// </param>
        /// <returns>
        /// See the <see cref="ISQLiteManagedModule.Release" /> method.
        /// </returns>
        public override SQLiteErrorCode Release(
            SQLiteVirtualTable table,
            int savepoint
            )
        {
            CheckDisposed();

            return GetMethodResultCode("Release");
        }

        ///////////////////////////////////////////////////////////////////////

        /// <summary>
        /// See the <see cref="ISQLiteManagedModule.RollbackTo" /> method.
        /// </summary>
        /// <param name="table">
        /// See the <see cref="ISQLiteManagedModule.RollbackTo" /> method.
        /// </param>
        /// <param name="savepoint">
        /// See the <see cref="ISQLiteManagedModule.RollbackTo" /> method.
        /// </param>
        /// <returns>
        /// See the <see cref="ISQLiteManagedModule.RollbackTo" /> method.
        /// </returns>
        public override SQLiteErrorCode RollbackTo(
            SQLiteVirtualTable table,
            int savepoint
            )
        {
            CheckDisposed();

            return GetMethodResultCode("RollbackTo");
        }
        #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(SQLiteModuleNoop).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
    }
}