100 lines
2.0 KiB
Go
100 lines
2.0 KiB
Go
package progress
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import (
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"bytes"
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"fmt"
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"io"
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"os"
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"regexp"
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"strings"
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"github.com/containerd/console"
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)
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var (
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regexCleanLine = regexp.MustCompile("\x1b\\[[0-9]+m[\x1b]?")
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)
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// Writer buffers writes until flush, at which time the last screen is cleared
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// and the current buffer contents are written. This is useful for
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// implementing progress displays, such as those implemented in docker and
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// git.
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type Writer struct {
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buf bytes.Buffer
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w io.Writer
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lines int
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}
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// NewWriter returns a writer
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func NewWriter(w io.Writer) *Writer {
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return &Writer{
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w: w,
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}
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}
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// Write the provided bytes
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func (w *Writer) Write(p []byte) (n int, err error) {
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return w.buf.Write(p)
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}
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// Flush should be called when refreshing the current display.
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func (w *Writer) Flush() error {
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if w.buf.Len() == 0 {
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return nil
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}
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if err := w.clearLines(); err != nil {
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return err
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}
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w.lines = countLines(w.buf.String())
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if _, err := w.w.Write(w.buf.Bytes()); err != nil {
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return err
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}
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w.buf.Reset()
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return nil
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}
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// TODO(stevvooe): The following are system specific. Break these out if we
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// decide to build this package further.
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func (w *Writer) clearLines() error {
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for i := 0; i < w.lines; i++ {
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if _, err := fmt.Fprintf(w.w, "\x1b[1A\x1b[2K\r"); err != nil {
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return err
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}
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}
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return nil
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}
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// countLines in the output. If a line is longer than the console width then
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// an extra line is added to the count for each wrapped line. If the console
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// width is undefined then 0 is returned so that no lines are cleared on the next
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// flush.
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func countLines(output string) int {
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con, err := console.ConsoleFromFile(os.Stdin)
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if err != nil {
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return 0
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}
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ws, err := con.Size()
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if err != nil {
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return 0
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}
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width := int(ws.Width)
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if width <= 0 {
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return 0
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}
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strlines := strings.Split(output, "\n")
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lines := -1
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for _, line := range strlines {
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lines += (len(stripLine(line))-1)/width + 1
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}
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return lines
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}
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func stripLine(line string) string {
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return string(regexCleanLine.ReplaceAll([]byte(line), []byte{}))
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}
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