input_posix.go

Documentation: github.com/c-bata/go-prompt

     1  // +build !windows
     2  
     3  package prompt
     4  
     5  import (
     6  	"syscall"
     7  
     8  	"github.com/c-bata/go-prompt/internal/term"
     9  	"golang.org/x/sys/unix"
    10  )
    11  
    12  const maxReadBytes = 1024
    13  
    14  // PosixParser is a ConsoleParser implementation for POSIX environment.
    15  type PosixParser struct {
    16  	fd          int
    17  	origTermios syscall.Termios
    18  }
    19  
    20  // Setup should be called before starting input
    21  func (t *PosixParser) Setup() error {
    22  	// Set NonBlocking mode because if syscall.Read block this goroutine, it cannot receive data from stopCh.
    23  	if err := syscall.SetNonblock(t.fd, true); err != nil {
    24  		return err
    25  	}
    26  	if err := term.SetRaw(t.fd); err != nil {
    27  		return err
    28  	}
    29  	return nil
    30  }
    31  
    32  // TearDown should be called after stopping input
    33  func (t *PosixParser) TearDown() error {
    34  	if err := syscall.SetNonblock(t.fd, false); err != nil {
    35  		return err
    36  	}
    37  	if err := term.Restore(); err != nil {
    38  		return err
    39  	}
    40  	return nil
    41  }
    42  
    43  // Read returns byte array.
    44  func (t *PosixParser) Read() ([]byte, error) {
    45  	buf := make([]byte, maxReadBytes)
    46  	n, err := syscall.Read(t.fd, buf)
    47  	if err != nil {
    48  		return []byte{}, err
    49  	}
    50  	return buf[:n], nil
    51  }
    52  
    53  // GetWinSize returns WinSize object to represent width and height of terminal.
    54  func (t *PosixParser) GetWinSize() *WinSize {
    55  	ws, err := unix.IoctlGetWinsize(t.fd, unix.TIOCGWINSZ)
    56  	if err != nil {
    57  		panic(err)
    58  	}
    59  	return &WinSize{
    60  		Row: ws.Row,
    61  		Col: ws.Col,
    62  	}
    63  }
    64  
    65  var _ ConsoleParser = &PosixParser{}
    66  
    67  // NewStandardInputParser returns ConsoleParser object to read from stdin.
    68  func NewStandardInputParser() *PosixParser {
    69  	in, err := syscall.Open("/dev/tty", syscall.O_RDONLY, 0)
    70  	if err != nil {
    71  		panic(err)
    72  	}
    73  
    74  	return &PosixParser{
    75  		fd: in,
    76  	}
    77  }
    78
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