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Goalchemy

std/io/hostio

import "github.com/eugenioenko/goalchemy/std/io/hostio"

Package hostio adapts host streams passed to library exports as std/io interfaces. The compiler includes it in libraries whose exports take std/io parameters; programs do not import it directly. Each operation is a host callback named “goalchemy.stream.<id>” carrying a one-byte opcode: ‘r’ with an 8-byte count, ‘w’ with data, ‘s’ with an 8-byte offset and 1-byte whence, or ‘c’. Every reply starts with a status byte: 0 for success, 1 for a read that reached end of stream, or 2 for a host error followed by its message. Read data, or the 8-byte big-endian write count or seek position, follows a success status.

const MaxChunk = 128<<10 - 16

MaxChunk bounds the bytes moved by one host operation, within every target’s callback reply limit.

const MaxView = 1 << 20

MaxView bounds the bytes one host read of a source stream returns.

CloseView

Section titled “CloseView”
func CloseView(c io.Closer) error

CloseView closes c for a host stream view.

ReadCloser

Section titled “ReadCloser”
func ReadCloser(id int64) io.ReadCloser

ReadCloser returns the host stream id as an io.ReadCloser.

ReadSeekCloser

Section titled “ReadSeekCloser”
func ReadSeekCloser(id int64) io.ReadSeekCloser

ReadSeekCloser returns the host stream id as an io.ReadSeekCloser.

ReadSeeker

Section titled “ReadSeeker”
func ReadSeeker(id int64) io.ReadSeeker

ReadSeeker returns the host stream id as an io.ReadSeeker.

ReadView

Section titled “ReadView”
func ReadView(r io.Reader, n int) ([]byte, bool, error)

ReadView reads at most n bytes from r for a host stream view. It retries empty reads, so it returns data, end of stream, or an error. eof reports that r returned io.EOF; data read before it is returned with it.

ReadWriter

Section titled “ReadWriter”
func ReadWriter(id int64) io.ReadWriter

ReadWriter returns the host stream id as an io.ReadWriter.

Reader

Section titled “Reader”
func Reader(id int64) io.Reader

Reader returns the host stream id as an io.Reader.

SeekView

Section titled “SeekView”
func SeekView(s io.Seeker, offset int64, whence int) (int64, error)

SeekView seeks s for a host stream view.

WriteCloser

Section titled “WriteCloser”
func WriteCloser(id int64) io.WriteCloser

WriteCloser returns the host stream id as an io.WriteCloser.

WriteSeeker

Section titled “WriteSeeker”
func WriteSeeker(id int64) io.WriteSeeker

WriteSeeker returns the host stream id as an io.WriteSeeker.

WriteView

Section titled “WriteView”
func WriteView(w io.Writer, p []byte) (int, error)

WriteView writes all of p to w for a host stream view.

Writer

Section titled “Writer”
func Writer(id int64) io.Writer

Writer returns the host stream id as an io.Writer.

type Stream

Section titled “type Stream”
type Stream struct {
}

Stream is a host stream identified by a per-call registry number.

Stream.Close

Section titled “Stream.Close”
func (s *Stream) Close() error

Stream.Read

Section titled “Stream.Read”
func (s *Stream) Read(p []byte) (int, error)

Stream.Seek

Section titled “Stream.Seek”
func (s *Stream) Seek(offset int64, whence int) (int64, error)

Stream.Write

Section titled “Stream.Write”
func (s *Stream) Write(p []byte) (int, error)