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.Generic;
using System.Globalization;
using System.Runtime.CompilerServices;
using System.Runtime.InteropServices;
using System.Text;

namespace System.Data.SQLite
{
    #region SQLiteContext Helper Class
    /// <summary>

#if !PLATFORM_COMPACTFRAMEWORK
            Marshal.WriteIntPtr(pointer, offset, value);
#else
            Marshal.WriteIntPtr(IntPtrForOffset(pointer, offset), value);
#endif
        }
        #endregion

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

        #region Object Helper Methods
        /// <summary>
        /// Generates a hash code value for the object.
        /// </summary>
        /// <param name="value">
        /// The object instance used to calculate the hash code.
        /// </param>
        /// <param name="identity">
        /// Non-zero if different object instances with the same value should
        /// generate different hash codes, where applicable.  This parameter
        /// has no effect on the .NET Compact Framework.
        /// </param>
        /// <returns>
        /// The hash code value -OR- zero if the object is null.
        /// </returns>
        public static int GetHashCode(
            object value,
            bool identity
            )
        {
#if !PLATFORM_COMPACTFRAMEWORK
            if (identity)
                return RuntimeHelpers.GetHashCode(value);
#endif

            if (value == null) return 0;
            return value.GetHashCode();
        }
        #endregion
    }
    #endregion

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

    #region SQLiteModule Base Class
    /// <summary>

                IntPtr pAux,
                int argc,
                IntPtr argv,
                ref IntPtr pVtab,
                ref IntPtr pError
                )
            {
                //
                // NOTE: Called by native code.
                //
                // CheckDisposed(); /* EXEMPT */

                if (module == null)
                {
                    pError = SQLiteString.Utf8IntPtrFromString(
                        ModuleNotAvailableErrorMessage);

                    return SQLiteErrorCode.Error;

                IntPtr pAux,
                int argc,
                IntPtr argv,
                ref IntPtr pVtab,
                ref IntPtr pError
                )
            {
                //
                // NOTE: Called by native code.
                //
                // CheckDisposed(); /* EXEMPT */

                if (module == null)
                {
                    pError = SQLiteString.Utf8IntPtrFromString(
                        ModuleNotAvailableErrorMessage);

                    return SQLiteErrorCode.Error;

            /// See the <see cref="ISQLiteNativeModule.xBestIndex" /> method.
            /// </returns>
            public SQLiteErrorCode xBestIndex(
                IntPtr pVtab,
                IntPtr pIndex
                )
            {
                //
                // NOTE: Called by native code.
                //
                // CheckDisposed(); /* EXEMPT */

                if (module == null)
                    return ModuleNotAvailableTableError(pVtab);

                return module.xBestIndex(pVtab, pIndex);
            }

            /// <returns>
            /// See the <see cref="ISQLiteNativeModule.xDisconnect" /> method.
            /// </returns>
            public SQLiteErrorCode xDisconnect(
                IntPtr pVtab
                )
            {
                //
                // NOTE: Called by native code.
                //
                // CheckDisposed(); /* EXEMPT */

                if (module == null)
                    return ModuleNotAvailableTableError(pVtab);

                return module.xDisconnect(pVtab);
            }

            /// <returns>
            /// See the <see cref="ISQLiteNativeModule.xDestroy" /> method.
            /// </returns>
            public SQLiteErrorCode xDestroy(
                IntPtr pVtab
                )
            {
                //
                // NOTE: Called by native code.
                //
                // CheckDisposed(); /* EXEMPT */

                if (module == null)
                    return ModuleNotAvailableTableError(pVtab);

                return module.xDestroy(pVtab);
            }

            /// See the <see cref="ISQLiteNativeModule.xOpen" /> method.
            /// </returns>
            public SQLiteErrorCode xOpen(
                IntPtr pVtab,
                ref IntPtr pCursor
                )
            {
                //
                // NOTE: Called by native code.
                //
                // CheckDisposed(); /* EXEMPT */

                if (module == null)
                    return ModuleNotAvailableTableError(pVtab);

                return module.xOpen(pVtab, ref pCursor);
            }

            /// <returns>
            /// See the <see cref="ISQLiteNativeModule.xClose" /> method.
            /// </returns>
            public SQLiteErrorCode xClose(
                IntPtr pCursor
                )
            {
                //
                // NOTE: Called by native code.
                //
                // CheckDisposed(); /* EXEMPT */

                if (module == null)
                    return ModuleNotAvailableCursorError(pCursor);

                return module.xClose(pCursor);
            }

                IntPtr pCursor,
                int idxNum,
                IntPtr idxStr,
                int argc,
                IntPtr argv
                )
            {
                //
                // NOTE: Called by native code.
                //
                // CheckDisposed(); /* EXEMPT */

                if (module == null)
                    return ModuleNotAvailableCursorError(pCursor);

                return module.xFilter(pCursor, idxNum, idxStr, argc, argv);
            }

            /// <returns>
            /// See the <see cref="ISQLiteNativeModule.xNext" /> method.
            /// </returns>
            public SQLiteErrorCode xNext(
                IntPtr pCursor
                )
            {
                //
                // NOTE: Called by native code.
                //
                // CheckDisposed(); /* EXEMPT */

                if (module == null)
                    return ModuleNotAvailableCursorError(pCursor);

                return module.xNext(pCursor);
            }

            /// <returns>
            /// See the <see cref="ISQLiteNativeModule.xEof" /> method.
            /// </returns>
            public int xEof(
                IntPtr pCursor
                )
            {
                //
                // NOTE: Called by native code.
                //
                // CheckDisposed(); /* EXEMPT */

                if (module == null)
                {
                    ModuleNotAvailableCursorError(pCursor);
                    return 1;
                }

            /// </returns>
            public SQLiteErrorCode xColumn(
                IntPtr pCursor,
                IntPtr pContext,
                int index
                )
            {
                //
                // NOTE: Called by native code.
                //
                // CheckDisposed(); /* EXEMPT */

                if (module == null)
                    return ModuleNotAvailableCursorError(pCursor);

                return module.xColumn(pCursor, pContext, index);
            }

            /// See the <see cref="ISQLiteNativeModule.xRowId" /> method.
            /// </returns>
            public SQLiteErrorCode xRowId(
                IntPtr pCursor,
                ref long rowId
                )
            {
                //
                // NOTE: Called by native code.
                //
                // CheckDisposed(); /* EXEMPT */

                if (module == null)
                    return ModuleNotAvailableCursorError(pCursor);

                return module.xRowId(pCursor, ref rowId);
            }

            public SQLiteErrorCode xUpdate(
                IntPtr pVtab,
                int argc,
                IntPtr argv,
                ref long rowId
                )
            {
                //
                // NOTE: Called by native code.
                //
                // CheckDisposed(); /* EXEMPT */

                if (module == null)
                    return ModuleNotAvailableTableError(pVtab);

                return module.xUpdate(pVtab, argc, argv, ref rowId);
            }

            /// <returns>
            /// See the <see cref="ISQLiteNativeModule.xBegin" /> method.
            /// </returns>
            public SQLiteErrorCode xBegin(
                IntPtr pVtab
                )
            {
                //
                // NOTE: Called by native code.
                //
                // CheckDisposed(); /* EXEMPT */

                if (module == null)
                    return ModuleNotAvailableTableError(pVtab);

                return module.xBegin(pVtab);
            }

            /// <returns>
            /// See the <see cref="ISQLiteNativeModule.xSync" /> method.
            /// </returns>
            public SQLiteErrorCode xSync(
                IntPtr pVtab
                )
            {
                //
                // NOTE: Called by native code.
                //
                // CheckDisposed(); /* EXEMPT */

                if (module == null)
                    return ModuleNotAvailableTableError(pVtab);

                return module.xSync(pVtab);
            }

            /// <returns>
            /// See the <see cref="ISQLiteNativeModule.xCommit" /> method.
            /// </returns>
            public SQLiteErrorCode xCommit(
                IntPtr pVtab
                )
            {
                //
                // NOTE: Called by native code.
                //
                // CheckDisposed(); /* EXEMPT */

                if (module == null)
                    return ModuleNotAvailableTableError(pVtab);

                return module.xCommit(pVtab);
            }

            /// <returns>
            /// See the <see cref="ISQLiteNativeModule.xRollback" /> method.
            /// </returns>
            public SQLiteErrorCode xRollback(
                IntPtr pVtab
                )
            {
                //
                // NOTE: Called by native code.
                //
                // CheckDisposed(); /* EXEMPT */

                if (module == null)
                    return ModuleNotAvailableTableError(pVtab);

                return module.xRollback(pVtab);
            }

                IntPtr pVtab,
                int nArg,
                IntPtr zName,
                ref SQLiteCallback callback,
                ref IntPtr pClientData
                )
            {
                //
                // NOTE: Called by native code.
                //
                // CheckDisposed(); /* EXEMPT */

                if (module == null)
                {
                    ModuleNotAvailableTableError(pVtab);
                    return 0;
                }

            /// See the <see cref="ISQLiteNativeModule.xRename" /> method.
            /// </returns>
            public SQLiteErrorCode xRename(
                IntPtr pVtab,
                IntPtr zNew
                )
            {
                //
                // NOTE: Called by native code.
                //
                // CheckDisposed(); /* EXEMPT */

                if (module == null)
                    return ModuleNotAvailableTableError(pVtab);

                return module.xRename(pVtab, zNew);
            }

            /// See the <see cref="ISQLiteNativeModule.xSavepoint" /> method.
            /// </returns>
            public SQLiteErrorCode xSavepoint(
                IntPtr pVtab,
                int iSavepoint
                )
            {
                //
                // NOTE: Called by native code.
                //
                // CheckDisposed(); /* EXEMPT */

                if (module == null)
                    return ModuleNotAvailableTableError(pVtab);

                return module.xSavepoint(pVtab, iSavepoint);
            }

            /// See the <see cref="ISQLiteNativeModule.xRelease" /> method.
            /// </returns>
            public SQLiteErrorCode xRelease(
                IntPtr pVtab,
                int iSavepoint
                )
            {
                //
                // NOTE: Called by native code.
                //
                // CheckDisposed(); /* EXEMPT */

                if (module == null)
                    return ModuleNotAvailableTableError(pVtab);

                return module.xRelease(pVtab, iSavepoint);
            }

            /// See the <see cref="ISQLiteNativeModule.xRollbackTo" /> method.
            /// </returns>
            public SQLiteErrorCode xRollbackTo(
                IntPtr pVtab,
                int iSavepoint
                )
            {
                //
                // NOTE: Called by native code.
                //
                // CheckDisposed(); /* EXEMPT */

                if (module == null)
                    return ModuleNotAvailableTableError(pVtab);

                return module.xRollbackTo(pVtab, iSavepoint);
            }
            #endregion

        #region Private Data
        /// <summary>
        /// The <see cref="IEnumerable" /> instance containing the backing data
        /// for the virtual table.
        /// </summary>
        private IEnumerable enumerable;

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

        /// <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>
        /// <param name="enumerable">
        /// The <see cref="IEnumerable" /> instance to expose as a virtual
        /// table.  This parameter cannot be null.
        /// </param>
        public SQLiteModuleEnumerable(
            string name,
            IEnumerable enumerable
            )
            : this(name, enumerable, 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="enumerable">
        /// The <see cref="IEnumerable" /> instance to expose as a virtual
        /// table.  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 SQLiteModuleEnumerable(
            string name,
            IEnumerable enumerable,
            bool objectIdentity
            )
            : base(name)
        {
            if (enumerable == null)
                throw new ArgumentNullException("enumerable");

            this.enumerable = enumerable;
            this.objectIdentity = objectIdentity;
        }
        #endregion

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

        #region Protected Methods
        /// <summary>

        /// 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 ISQLiteManagedModule Members
        /// <summary>