System.Data.SQLite

/********************************************************
 * 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;
using System.Globalization;

namespace System.Data.SQLite
{
    #region SQLiteVirtualTableCursorEnumerator Class
    /// <summary>
    /// This class represents a virtual table cursor to be used with the
    /// <see cref="SQLiteModuleEnumerable" /> class.  It is not sealed and may
    /// be used as the base class for any user-defined virtual table cursor
    /// class that wraps an <see cref="IEnumerator" /> object instance.
    /// </summary>
    public class SQLiteVirtualTableCursorEnumerator :
            SQLiteVirtualTableCursor /* NOT SEALED */
    {
        #region Private Data
        /// <summary>
        /// The <see cref="IEnumerator" /> instance provided when this cursor
        /// was created.
        /// </summary>

        /// The <see cref="SQLiteVirtualTable" /> object instance associated
        /// with this object instance.
        /// </param>
        /// <param name="enumerator">
        /// The <see cref="IEnumerator" /> instance to expose as a virtual
        /// table cursor.
        /// </param>
        public SQLiteVirtualTableCursorEnumerator(
            SQLiteVirtualTable table,
            IEnumerator enumerator
            )
            : base(table)
        {
            this.enumerator = enumerator;
            this.endOfEnumerator = true;

        /// </summary>
        private void CheckDisposed() /* throw */
        {
#if THROW_ON_DISPOSED
            if (disposed)
            {
                throw new ObjectDisposedException(
                    typeof(SQLiteVirtualTableCursorEnumerator).Name);
            }
#endif
        }

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

        /// <summary>

    #endregion

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

    #region SQLiteModuleEnumerable Class
    /// <summary>
    /// This class implements a virtual table module that exposes an
    /// <see cref="IEnumerable" /> object instance as a read-only virtual
    /// table.  It is not sealed and may be used as the base class for any
    /// user-defined virtual table class that wraps an
    /// <see cref="IEnumerable" /> object instance.
    /// </summary>
    public class SQLiteModuleEnumerable : SQLiteModuleNoop /* NOT SEALED */
    {
        #region Private Constants
        /// <summary>
        /// The CREATE TABLE statement used to declare the schema for the
        /// virtual table.

        /// <returns>
        /// The value of <see cref="SQLiteErrorCode.Error"/>.
        /// </returns>
        protected virtual SQLiteErrorCode CursorTypeMismatchError(
            SQLiteVirtualTableCursor cursor
            )
        {
            SetCursorError(cursor, "not an \"enumerator\" cursor");
            return SQLiteErrorCode.Error;
        }

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

        /// <summary>
        /// Sets the table error message to one that indicates the virtual

        public override SQLiteErrorCode Open(
            SQLiteVirtualTable table,
            ref SQLiteVirtualTableCursor cursor
            )
        {
            CheckDisposed();

            cursor = new SQLiteVirtualTableCursorEnumerator(
                table, enumerable.GetEnumerator());

            return SQLiteErrorCode.Ok;
        }

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

        /// </returns>
        public override SQLiteErrorCode Close(
            SQLiteVirtualTableCursor cursor
            )
        {
            CheckDisposed();

            SQLiteVirtualTableCursorEnumerator enumeratorCursor =
                cursor as SQLiteVirtualTableCursorEnumerator;

            if (enumeratorCursor == null)
                return CursorTypeMismatchError(cursor);

            enumeratorCursor.Close();
            return SQLiteErrorCode.Ok;
        }

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

        /// <summary>
        /// See the <see cref="ISQLiteManagedModule.Filter" /> method.

            int indexNumber,
            string indexString,
            SQLiteValue[] values
            )
        {
            CheckDisposed();

            SQLiteVirtualTableCursorEnumerator enumeratorCursor =
                cursor as SQLiteVirtualTableCursorEnumerator;

            if (enumeratorCursor == null)
                return CursorTypeMismatchError(cursor);

            enumeratorCursor.Filter(indexNumber, indexString, values);
            enumeratorCursor.Reset(); /* NO RESULT */
            enumeratorCursor.MoveNext(); /* IGNORED */

            return SQLiteErrorCode.Ok;
        }

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

        /// <summary>

        /// </returns>
        public override SQLiteErrorCode Next(
            SQLiteVirtualTableCursor cursor
            )
        {
            CheckDisposed();

            SQLiteVirtualTableCursorEnumerator enumeratorCursor =
                cursor as SQLiteVirtualTableCursorEnumerator;

            if (enumeratorCursor == null)
                return CursorTypeMismatchError(cursor);

            if (enumeratorCursor.EndOfEnumerator)
                return CursorEndOfEnumeratorError(cursor);

            enumeratorCursor.MoveNext(); /* IGNORED */
            return SQLiteErrorCode.Ok;
        }

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

        /// <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();

            SQLiteVirtualTableCursorEnumerator enumeratorCursor =
                cursor as SQLiteVirtualTableCursorEnumerator;

            if (enumeratorCursor == null)
                return ResultCodeToEofResult(CursorTypeMismatchError(cursor));

            return enumeratorCursor.EndOfEnumerator;
        }

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

        /// <summary>
        /// See the <see cref="ISQLiteManagedModule.Column" /> method.
        /// </summary>

            SQLiteVirtualTableCursor cursor,
            SQLiteContext context,
            int index
            )
        {
            CheckDisposed();

            SQLiteVirtualTableCursorEnumerator enumeratorCursor =
                cursor as SQLiteVirtualTableCursorEnumerator;

            if (enumeratorCursor == null)
                return CursorTypeMismatchError(cursor);

            if (enumeratorCursor.EndOfEnumerator)
                return CursorEndOfEnumeratorError(cursor);

            object current = enumeratorCursor.Current;

            if (current != null)
                context.SetString(GetStringFromObject(current));
            else
                context.SetNull();

            return SQLiteErrorCode.Ok;

        public override SQLiteErrorCode RowId(
            SQLiteVirtualTableCursor cursor,
            ref long rowId
            )
        {
            CheckDisposed();

            SQLiteVirtualTableCursorEnumerator enumeratorCursor =
                cursor as SQLiteVirtualTableCursorEnumerator;

            if (enumeratorCursor == null)
                return CursorTypeMismatchError(cursor);

            if (enumeratorCursor.EndOfEnumerator)
                return CursorEndOfEnumeratorError(cursor);

            object current = enumeratorCursor.Current;

            rowId = GetRowIdFromObject(current);
            return SQLiteErrorCode.Ok;
        }

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