out.go

Documentation: github.com/docker/cli/cli/streams

     1  package streams
     2  
     3  import (
     4  	"io"
     5  	"os"
     6  
     7  	"github.com/moby/term"
     8  	"github.com/sirupsen/logrus"
     9  )
    10  
    11  // Out is an output stream to write normal program output. It implements
    12  // an [io.Writer], with additional utilities for detecting whether a terminal
    13  // is connected, getting the TTY size, and putting the terminal in raw mode.
    14  type Out struct {
    15  	commonStream
    16  	out io.Writer
    17  }
    18  
    19  func (o *Out) Write(p []byte) (int, error) {
    20  	return o.out.Write(p)
    21  }
    22  
    23  // SetRawTerminal puts the output of the terminal connected to the stream
    24  // into raw mode.
    25  //
    26  // On UNIX, this does nothing. On Windows, it disables LF -> CRLF/ translation.
    27  // It is a no-op if Out is not a TTY, or if the "NORAW" environment variable is
    28  // set to a non-empty value.
    29  func (o *Out) SetRawTerminal() (err error) {
    30  	if !o.isTerminal || os.Getenv("NORAW") != "" {
    31  		return nil
    32  	}
    33  	o.state, err = term.SetRawTerminalOutput(o.fd)
    34  	return err
    35  }
    36  
    37  // GetTtySize returns the height and width in characters of the TTY, or
    38  // zero for both if no TTY is connected.
    39  func (o *Out) GetTtySize() (height uint, width uint) {
    40  	if !o.isTerminal {
    41  		return 0, 0
    42  	}
    43  	ws, err := term.GetWinsize(o.fd)
    44  	if err != nil {
    45  		logrus.WithError(err).Debug("Error getting TTY size")
    46  		if ws == nil {
    47  			return 0, 0
    48  		}
    49  	}
    50  	return uint(ws.Height), uint(ws.Width)
    51  }
    52  
    53  // NewOut returns a new [Out] from an [io.Writer].
    54  func NewOut(out io.Writer) *Out {
    55  	o := &Out{out: out}
    56  	o.fd, o.isTerminal = term.GetFdInfo(out)
    57  	return o
    58  }
    59
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