stream

Documentation

Overview

Package stream provides NullStream

Packate stream defines input and output streams.

Index

• Variables
• func IsNullWriter(writer io.Writer) bool
• type IOStream
  • func FromEnv() IOStream
  • func FromNil() IOStream
  • func NewIOStream(Stdout, Stderr io.Writer, Stdin io.Reader, wrap int) IOStream
  • func NonInteractive(Writer io.Writer) IOStream
  • func (str IOStream) Die(err error) error
  • func (str IOStream) EPrint(args ...interface{}) (n int, err error)
  • func (str IOStream) EPrintf(format string, args ...interface{}) (n int, err error)
  • func (str IOStream) EPrintln(args ...interface{}) (n int, err error)
  • func (str IOStream) NonInteractive() IOStream
  • func (str IOStream) Print(args ...interface{}) (n int, err error)
  • func (str IOStream) Printf(format string, args ...interface{}) (n int, err error)
  • func (str IOStream) Println(args ...interface{}) (n int, err error)
  • func (str IOStream) ReadLine() (string, error)
  • func (str IOStream) ReadPassword() (string, error)
  • func (str IOStream) ReadPasswordStrict() (string, error)
  • func (str IOStream) StderrIsATerminal() bool
  • func (str IOStream) StderrWriteWrap(s string) (int, error)
  • func (str IOStream) StdinIsATerminal() bool
  • func (str IOStream) StdoutIsATerminal() bool
  • func (str IOStream) StdoutWriteWrap(s string) (int, error)
  • func (str IOStream) Streams(Stdout, Stderr io.Writer, Stdin io.Reader, wrap int) IOStream

Variables

var Null io.ReadWriteCloser = nullStream{}

Null is an io.ReadWriteCloser.

Reads from it return 0 bytes and io.EOF. Writes and Closes succeed without doing anything.

See also io.Discard.

Functions

func IsNullWriter

func IsNullWriter(writer io.Writer) bool

IsNullWriter checks if a writer is known to be a writer that discards any input

Types

type IOStream

type IOStream struct {
	Stdin          io.Reader
	Stdout, Stderr io.Writer
	// contains filtered or unexported fields
}

IOStream represents a set of input and output streams commonly associated to a process.

func FromEnv

func FromEnv() IOStream

FromEnv creates a new IOStream using the environment.

The Stdin, Stdout and Stderr streams are used from the os package.

func FromNil

func FromNil() IOStream

FromNil creates a new IOStream that silences all output and provides no input.

func NewIOStream

func NewIOStream(Stdout, Stderr io.Writer, Stdin io.Reader, wrap int) IOStream

NewIOStream creates a new IOStream with the provided readers and writers. If any of them are set to nil, they are set to Null. When wrap is set to 0, it is set to a reasonable default.

It furthermore wraps output as set by wrap.

func NonInteractive

func NonInteractive(Writer io.Writer) IOStream

NonInteractive creates a new non-interactive writer from a single output stream.

It is roughly equivalent to NewIOStream(Writer, Writer, nil, 0)

func (IOStream) Die

func (str IOStream) Die(err error) error

Die prints a non-nil err to io.Stderr and returns an error of type Error or nil.

When error is non-nil, this function first turns err into type Error. Then if err.Message is not the empty string, it prints it to io.Stderr with wrapping.

If err is nil, it does nothing and returns nil.

func (IOStream) EPrint

func (str IOStream) EPrint(args ...interface{}) (n int, err error)

EPrint is like fmt.Print but prints to str.Stderr.

func (IOStream) EPrintf

func (str IOStream) EPrintf(format string, args ...interface{}) (n int, err error)

EPrintf is like fmt.Printf but prints to io.Stderr.

func (IOStream) EPrintln

func (str IOStream) EPrintln(args ...interface{}) (n int, err error)

EPrintln is like fmt.Println but prints to io.Stderr.

func (IOStream) NonInteractive

func (str IOStream) NonInteractive() IOStream

NonInteractive creates a new IOStream with Null as standard input.

func (IOStream) Print

func (str IOStream) Print(args ...interface{}) (n int, err error)

Print is like fmt.Print but prints to str.Stdout.

func (IOStream) Printf

func (str IOStream) Printf(format string, args ...interface{}) (n int, err error)

Printf is like fmt.Printf but prints to str.Stdout.

func (IOStream) Println

func (str IOStream) Println(args ...interface{}) (n int, err error)

Println is like fmt.Println but prints to str.Stdout.

func (IOStream) ReadLine

func (str IOStream) ReadLine() (string, error)

ReadLine is like nobufio.ReadLine on the standard input

func (IOStream) ReadPassword

func (str IOStream) ReadPassword() (string, error)

ReadPassword is like nobufio.ReadPassword on the standard input

func (IOStream) ReadPasswordStrict

func (str IOStream) ReadPasswordStrict() (string, error)

ReadPasswordStrict is like nobufio.ReadPasswordStrict on the standard input

func (IOStream) StderrIsATerminal

func (str IOStream) StderrIsATerminal() bool

StderrIsATerminal checks if standard error is a terminal

func (IOStream) StderrWriteWrap

func (str IOStream) StderrWriteWrap(s string) (int, error)

StderrWriteWrap is like

io.Stdout.Write([]byte(s + "\n"))

but wrapped at length Wrap.

func (IOStream) StdinIsATerminal

func (str IOStream) StdinIsATerminal() bool

StdinIsATerminal checks if standard input is a terminal

func (IOStream) StdoutIsATerminal

func (str IOStream) StdoutIsATerminal() bool

StdoutIsATerminal checks if standard output is a terminal

func (IOStream) StdoutWriteWrap

func (str IOStream) StdoutWriteWrap(s string) (int, error)

StdoutWriteWrap is like

io.Stdout.Write([]byte(s + "\n"))

but wrapped at a reasonable length

func (IOStream) Streams

func (str IOStream) Streams(Stdout, Stderr io.Writer, Stdin io.Reader, wrap int) IOStream

Streams creates a new IOStream with the provided streams and wrap. If any parameter is the zero value, copies the values from str.