niki/vendor/github.com/go-sql-driver/mysql/rows.go

// Go MySQL Driver - A MySQL-Driver for Go's database/sql package

//

// Copyright 2012 The Go-MySQL-Driver Authors. All rights reserved.

//

// This Source Code Form is subject to the terms of the Mozilla Public

// License, v. 2.0. If a copy of the MPL was not distributed with this file,

// You can obtain one at http://mozilla.org/MPL/2.0/.

package mysql

import (
	"database/sql/driver"
	"io"
	"math"
	"reflect"
)

type resultSet struct {
	columns []mysqlField

	columnNames []string

	done bool
}

type mysqlRows struct {
	mc *mysqlConn

	rs resultSet

	finish func()
}

type binaryRows struct {
	mysqlRows
}

type textRows struct {
	mysqlRows
}

func (rows *mysqlRows) Columns() []string {

	if rows.rs.columnNames != nil {

		return rows.rs.columnNames

	}

	columns := make([]string, len(rows.rs.columns))

	if rows.mc != nil && rows.mc.cfg.ColumnsWithAlias {

		for i := range columns {

			if tableName := rows.rs.columns[i].tableName; len(tableName) > 0 {

				columns[i] = tableName + "." + rows.rs.columns[i].name

			} else {

				columns[i] = rows.rs.columns[i].name

			}

		}

	} else {

		for i := range columns {

			columns[i] = rows.rs.columns[i].name

		}

	}

	rows.rs.columnNames = columns

	return columns

}

func (rows *mysqlRows) ColumnTypeDatabaseTypeName(i int) string {

	return rows.rs.columns[i].typeDatabaseName()

}

// func (rows *mysqlRows) ColumnTypeLength(i int) (length int64, ok bool) {

// 	return int64(rows.rs.columns[i].length), true

// }

func (rows *mysqlRows) ColumnTypeNullable(i int) (nullable, ok bool) {

	return rows.rs.columns[i].flags&flagNotNULL == 0, true

}

func (rows *mysqlRows) ColumnTypePrecisionScale(i int) (int64, int64, bool) {

	column := rows.rs.columns[i]

	decimals := int64(column.decimals)

	switch column.fieldType {

	case fieldTypeDecimal, fieldTypeNewDecimal:

		if decimals > 0 {

			return int64(column.length) - 2, decimals, true

		}

		return int64(column.length) - 1, decimals, true

	case fieldTypeTimestamp, fieldTypeDateTime, fieldTypeTime:

		return decimals, decimals, true

	case fieldTypeFloat, fieldTypeDouble:

		if decimals == 0x1f {

			return math.MaxInt64, math.MaxInt64, true

		}

		return math.MaxInt64, decimals, true

	}

	return 0, 0, false

}

func (rows *mysqlRows) ColumnTypeScanType(i int) reflect.Type {

	return rows.rs.columns[i].scanType()

}

func (rows *mysqlRows) Close() (err error) {

	if f := rows.finish; f != nil {

		f()

		rows.finish = nil

	}

	mc := rows.mc

	if mc == nil {

		return nil

	}

	if err := mc.error(); err != nil {

		return err

	}

	// flip the buffer for this connection if we need to drain it.

	// note that for a successful query (i.e. one where rows.next()

	// has been called until it returns false), `rows.mc` will be nil

	// by the time the user calls `(*Rows).Close`, so we won't reach this

	// see: https://github.com/golang/go/commit/651ddbdb5056ded455f47f9c494c67b389622a47

	mc.buf.flip()

	// Remove unread packets from stream

	if !rows.rs.done {

		err = mc.readUntilEOF()

	}

	if err == nil {

		if err = mc.discardResults(); err != nil {

			return err

		}

	}

	rows.mc = nil

	return err

}

func (rows *mysqlRows) HasNextResultSet() (b bool) {

	if rows.mc == nil {

		return false

	}

	return rows.mc.status&statusMoreResultsExists != 0

}

func (rows *mysqlRows) nextResultSet() (int, error) {

	if rows.mc == nil {

		return 0, io.EOF

	}

	if err := rows.mc.error(); err != nil {

		return 0, err

	}

	// Remove unread packets from stream

	if !rows.rs.done {

		if err := rows.mc.readUntilEOF(); err != nil {

			return 0, err

		}

		rows.rs.done = true

	}

	if !rows.HasNextResultSet() {

		rows.mc = nil

		return 0, io.EOF

	}

	rows.rs = resultSet{}

	return rows.mc.readResultSetHeaderPacket()

}

func (rows *mysqlRows) nextNotEmptyResultSet() (int, error) {

	for {

		resLen, err := rows.nextResultSet()

		if err != nil {

			return 0, err

		}

		if resLen > 0 {

			return resLen, nil

		}

		rows.rs.done = true

	}

}

func (rows *binaryRows) NextResultSet() error {

	resLen, err := rows.nextNotEmptyResultSet()

	if err != nil {

		return err

	}

	rows.rs.columns, err = rows.mc.readColumns(resLen)

	return err

}

func (rows *binaryRows) Next(dest []driver.Value) error {

	if mc := rows.mc; mc != nil {

		if err := mc.error(); err != nil {

			return err

		}

		// Fetch next row from stream

		return rows.readRow(dest)

	}

	return io.EOF

}

func (rows *textRows) NextResultSet() (err error) {

	resLen, err := rows.nextNotEmptyResultSet()

	if err != nil {

		return err

	}

	rows.rs.columns, err = rows.mc.readColumns(resLen)

	return err

}

func (rows *textRows) Next(dest []driver.Value) error {

	if mc := rows.mc; mc != nil {

		if err := mc.error(); err != nil {

			return err

		}

		// Fetch next row from stream

		return rows.readRow(dest)

	}

	return io.EOF

}