Ejemplo n.º 1
0
        ///////////////////////////////////////////////////////////////////////////////////////////////

        /// <summary>
        /// Creates a <see cref="SQLiteBlob" /> object.  This will not work
        /// for tables that were created WITHOUT ROWID.
        /// </summary>
        /// <param name="connection">
        /// The connection to use when opening the blob object.
        /// </param>
        /// <param name="databaseName">
        /// The name of the database containing the blob object.
        /// </param>
        /// <param name="tableName">
        /// The name of the table containing the blob object.
        /// </param>
        /// <param name="columnName">
        /// The name of the column containing the blob object.
        /// </param>
        /// <param name="rowId">
        /// The integer identifier for the row associated with the desired
        /// blob object.
        /// </param>
        /// <param name="readOnly">
        /// Non-zero to open the blob object for read-only access.
        /// </param>
        /// <returns>
        /// The newly created <see cref="SQLiteBlob" /> instance -OR- null
        /// if an error occurs.
        /// </returns>
        public static SQLiteBlob Create(
            SQLiteConnection connection,
            string databaseName,
            string tableName,
            string columnName,
            long rowId,
            bool readOnly
            )
        {
            if (connection == null)
            {
                throw new ArgumentNullException("connection");
            }

            SQLite3 sqlite3 = connection._sql as SQLite3;

            if (sqlite3 == null)
            {
                throw new InvalidOperationException("Connection has no wrapper");
            }

            SQLiteConnectionHandle handle = sqlite3._sql;

            if (handle == null)
            {
                throw new InvalidOperationException("Connection has an invalid handle.");
            }

            SQLiteBlobHandle blob = null;

            try
            {
                // do nothing.
            }
            finally /* NOTE: Thread.Abort() protection. */
            {
                IntPtr ptrBlob = IntPtr.Zero;

                SQLiteErrorCode rc = UnsafeNativeMethods.sqlite3_blob_open(
                    handle, SQLiteConvert.ToUTF8(databaseName),
                    SQLiteConvert.ToUTF8(tableName), SQLiteConvert.ToUTF8(
                        columnName), rowId, readOnly ? 0 : 1, ref ptrBlob);

                if (rc != SQLiteErrorCode.Ok)
                {
                    throw new SQLiteException(rc, null);
                }

                blob = new SQLiteBlobHandle(handle, ptrBlob);
            }

            SQLiteConnection.OnChanged(connection, new ConnectionEventArgs(
                                           SQLiteConnectionEventType.NewCriticalHandle, null, null,
                                           null, null, blob, null, new object[] { typeof(SQLiteBlob),
                                                                                  databaseName, tableName, columnName, rowId, readOnly }));

            return(new SQLiteBlob(sqlite3, blob));
        }
        ///////////////////////////////////////////////////////////////////////////////////////////////

        #region Static "Factory" Methods
        /// <summary>
        /// Creates a <see cref="SQLiteBlob" /> object.  This will not work
        /// for tables that were created WITHOUT ROWID -OR- if the query
        /// does not include the "rowid" column or one of its aliases -OR-
        /// if the <see cref="SQLiteDataReader" /> was not created with the
        /// <see cref="CommandBehavior.KeyInfo" /> flag.
        /// </summary>
        /// <param name="dataReader">
        /// The <see cref="SQLiteDataReader" /> instance with a result set
        /// containing the desired blob column.
        /// </param>
        /// <param name="i">
        /// The index of the blob column.
        /// </param>
        /// <param name="readOnly">
        /// Non-zero to open the blob object for read-only access.
        /// </param>
        /// <returns>
        /// The newly created <see cref="SQLiteBlob" /> instance -OR- null
        /// if an error occurs.
        /// </returns>
        public static SQLiteBlob Create(
            SQLiteDataReader dataReader,
            int i,
            bool readOnly
            )
        {
            SQLiteConnection connection = SQLiteDataReader.GetConnection(
                dataReader);

            if (connection == null)
            {
                throw new InvalidOperationException("Connection not available");
            }

            SQLite3 sqlite3 = connection._sql as SQLite3;

            if (sqlite3 == null)
            {
                throw new InvalidOperationException("Connection has no wrapper");
            }

            SQLiteConnectionHandle handle = sqlite3._sql;

            if (handle == null)
            {
                throw new InvalidOperationException("Connection has an invalid handle.");
            }

            long?rowId = dataReader.GetRowId(i);

            if (rowId == null)
            {
                throw new InvalidOperationException("No RowId is available");
            }

            SQLiteBlobHandle blob = null;

            try
            {
                // do nothing.
            }
            finally /* NOTE: Thread.Abort() protection. */
            {
                IntPtr ptrBlob = IntPtr.Zero;

                SQLiteErrorCode rc = UnsafeNativeMethods.sqlite3_blob_open(
                    sqlite3._sql, SQLiteConvert.ToUTF8(
                        dataReader.GetDatabaseName(i)), SQLiteConvert.ToUTF8(
                        dataReader.GetTableName(i)), SQLiteConvert.ToUTF8(
                        dataReader.GetName(i)), (long)rowId, readOnly ? 0 : 1,
                    ref ptrBlob);

                if (rc != SQLiteErrorCode.Ok)
                {
                    throw new SQLiteException(rc, null);
                }

                blob = new SQLiteBlobHandle(handle, ptrBlob);
            }

            SQLiteConnection.OnChanged(null, new ConnectionEventArgs(
                                           SQLiteConnectionEventType.NewCriticalHandle, null,
                                           null, null, dataReader, blob, null, new object[] {
                typeof(SQLiteBlob), dataReader, i, readOnly
            }));

            return(new SQLiteBlob(sqlite3, blob));
        }