format

Documentation

Index

• Variables
• func IsFormatErr(e error) bool
• func NewDimErr(ctx string, expected, got int) error
• func Wrap(ctx string, err error) error
• type Decoder
• type Encoder

Variables

var (
	//ErrNoHeader means that the names of columns need
	//to be specified by the input but were not.
	ErrNoHeader = errors.New("column names cannot be derived")

	//ErrFrameRequired means the format requires a table
	//name to choose the appropriate data table to decode.
	ErrFrameRequired = errors.New("frame name is required")
)

Functions

func IsFormatErr

func IsFormatErr(e error) bool

IsFormatErr returns whether e is an error in the format.

func NewDimErr

func NewDimErr(ctx string, expected, got int) error

NewDimErr creates a new dimension error when the input, described by ctx, expected n column but got m.

func Wrap

func Wrap(ctx string, err error) error

Wrap an error as a format error.

Types

type Decoder

type Decoder interface {
	//Name reports the name of the format being decoded.
	//It may be called at any time.
	Name() string

	//Init decoder to read from r.
	Init(r device.Reader) error

	//ReadHeader prepares the Decoder to read records from the current device.
	//
	//If ReadHeader is called on a format that contains multiple data frames
	//and no frame is provided, ReadHeader must return ErrFrameRequired.
	//
	//If ReadHeader is called on a format, or instance, that does not contain a header,
	//and no header is provided, ReadHeader must return ErrNoHeader.
	//
	//If a nonempty header is passed to ReadHeader, it must be returned.
	//
	//ReadHeader must never return data and an error.
	//
	//Clients must not assume it is safe to modify the returned slice.
	ReadHeader(frame string, header []string) ([]string, error)

	//Skip rows. Used by OFFSET.
	Skip(rows int) error

	//ReadRow will be called until it returns io.EOF
	//
	//ReadRow must never return data and an error.
	//
	//Clients must not assume it is safe to modify the returned slice.
	ReadRow() ([]*string, error)

	//Reset is called after an import.
	//
	//The next call will either be to Init or Close.
	Reset() error

	//Close is called when the Decoder will never be used again.
	Close() error
}

Decoder specifies the protocol for a format to be imported into a database.

A Decoder will be called with Init to set the input device.

For each table,

ReadHeader will be called once.
Skip will be called 0 or more times.
ReadRow will be called 0 or more times.
Reset will be called once.

When a Decoder is retired Close will be called once.

It may be re-initialized later with a different input device.

type Encoder

type Encoder interface {
	//Name reports the name of the format being encoded.
	//It may be called at any time.
	Name() string

	//Init encoder to write to w.
	Init(w device.Writer) error

	//WriteHeader may choose to not write the header, depending on format.
	//
	//If the format requires the name of a data frame to write and none is provided,
	//WriteHeader must return ErrFrameRequired.
	WriteHeader(frame string, header []string) error
	WriteRow([]*string) error
	Reset() error
	Close() error
}

Encoder encodes an SQLite table as text. For each table,

WriteHeader will be called once.
WriteRow will be called 0 or more times.
Reset will be called once.

When an Encoder is to be retired Close will be called once.