bfile.go

package go_ora

import (
	"bytes"
	"encoding/binary"
	"errors"
)

type BFile struct {
	isOpened bool
	lob      Lob
}

func NewBFile(connection *Connection, dirName, fileName string) (*BFile, error) {
	totalLen := 16 + len(dirName) + len(fileName) + 4
	locatorBuffer := new(bytes.Buffer)
	err := binary.Write(locatorBuffer, binary.BigEndian, uint16(totalLen-2))
	if err != nil {
		return nil, err
	}
	locatorBuffer.Write([]byte{0, 1, 8, 8, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0})
	err = binary.Write(locatorBuffer, binary.BigEndian, uint16(len(dirName)))
	if err != nil {
		return nil, err
	}
	if len(dirName) > 0 {
		locatorBuffer.Write(connection.sStrConv.Encode(dirName))
	}
	err = binary.Write(locatorBuffer, binary.BigEndian, uint16(len(fileName)))
	if err != nil {
		return nil, err
	}
	if len(fileName) > 0 {
		locatorBuffer.Write(connection.sStrConv.Encode(fileName))
	}
	return &BFile{lob: Lob{
		connection:    connection,
		sourceLocator: locatorBuffer.Bytes(),
		sourceLen:     locatorBuffer.Len(),
	},
	}, nil
}
func (file *BFile) IsOpen() bool {
	return file.isOpened
}
func (file *BFile) isInit() bool {
	return len(file.lob.sourceLocator) > 0
}
func (file *BFile) Open() error {
	if file.isOpened {
		return nil
	}
	if !file.isInit() {
		return errors.New("BFile is not initialized")
	}
	err := file.lob.open(0xB, 0x100)
	if err != nil {
		return err
	}
	file.isOpened = true
	return nil
}
func (file *BFile) Close() error {
	if !file.isOpened {
		return nil
	}
	if !file.isInit() {
		return errors.New("BFile is not initialized")
	}
	err := file.lob.close(0x200)
	if err != nil {
		return err
	}
	file.isOpened = false
	return nil
}
func (file *BFile) Exists() (bool, error) {
	if !file.isOpened {
		return false, errors.New("invalid operation on closed object")
	}
	if !file.isInit() {
		return false, errors.New("BFile is not initialized")
	}
	file.lob.initialize()
	file.lob.bNullO2U = true
	session := file.lob.connection.session
	session.ResetBuffer()
	file.lob.writeOp(0x800)
	err := session.Write()
	if err != nil {
		return false, err
	}
	err = file.lob.read()
	if err != nil {
		return false, err
	}
	return file.lob.isNull, nil
}

func (file *BFile) GetLength() (int64, error) {
	if !file.isOpened {
		return 0, errors.New("invalid operation on closed object")
	}
	return file.lob.getSize()
}

func (file *BFile) Read() ([]byte, error) {
	return file.lob.getDataWithOffsetSize(0, 0)
}
func (file *BFile) ReadFromPos(pos int64) ([]byte, error) {
	return file.lob.getDataWithOffsetSize(pos, 0)
}
func (file *BFile) ReadBytesFromPos(pos, count int64) ([]byte, error) {
	return file.lob.getDataWithOffsetSize(pos, count)
}

func (file *BFile) Scan(value interface{}) error {
	switch temp := value.(type) {
	case *BFile:
		file = temp
	case BFile:
		*file = temp
	default:
		return errors.New("BFILE column type require BFile value")
	}
	return nil
}