code-intelligence.com/cifuzz@v0.40.0/pkg/log/ptermwriter.go (about)

     1  package log
     2  
     3  import (
     4  	"fmt"
     5  	"io"
     6  	"sync"
     7  
     8  	"github.com/pkg/errors"
     9  )
    10  
    11  var ActiveUpdatingPrinter updatingPrinter
    12  
    13  type updatingPrinter interface {
    14  	Clear()
    15  }
    16  
    17  var writeLock sync.Mutex
    18  
    19  type ptermWriter struct {
    20  	buf []byte
    21  	out io.Writer
    22  }
    23  
    24  // NewPTermWriter returns a writer which ensures that the output written
    25  // by it doesn't mess with the output of an active pterm.SpinnerPrinter.
    26  func NewPTermWriter(out io.Writer) *ptermWriter {
    27  	return &ptermWriter{out: out}
    28  }
    29  
    30  func (w *ptermWriter) Write(p []byte) (int, error) {
    31  	// To avoid races, only one write is executed at a time
    32  	writeLock.Lock()
    33  	defer writeLock.Unlock()
    34  
    35  	// To ensure that after the write, the spinner printer has a new
    36  	// line for itself, we only write the output if it ends with a
    37  	// newline. Else, we store it in a buffer which we write the next
    38  	// time Write() is called with something that ends with a newline.
    39  	lenOldBuf := len(w.buf)
    40  	w.buf = append(w.buf, p...)
    41  	if len(p) == 0 || p[len(p)-1] != '\n' {
    42  		return len(p), nil
    43  	}
    44  
    45  	// Clear the updating printer output if any. We don't use
    46  	// pterm.Fprint here, which also tries to clear spinner printer
    47  	// output, because that only works when the spinner printer and this
    48  	// function write to the same output stream, which is not always the
    49  	// case.
    50  	if ActiveUpdatingPrinter != nil {
    51  		ActiveUpdatingPrinter.Clear()
    52  	}
    53  
    54  	// Write the buffer
    55  	n, err := fmt.Fprint(w.out, string(w.buf))
    56  
    57  	// Clear the buffer now that it was written
    58  	w.buf = []byte{}
    59  
    60  	// Return the number of bytes from p that were written. If
    61  	// fmt.Fprint printed all bytes from the buffer, this is n minus the
    62  	// length of the buffer before we appended p to it.
    63  	return n - lenOldBuf, errors.WithStack(err)
    64  }