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author | Valentin Rothberg <rothberg@redhat.com> | 2020-10-07 16:58:53 +0200 |
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committer | Valentin Rothberg <rothberg@redhat.com> | 2020-11-13 15:40:06 +0100 |
commit | 8e4a42aa429c6dec0d5face7c69554d8a0677e96 (patch) | |
tree | bbfff77e7b32a8b46af6f57d42965a7751bec18e /vendor/github.com/manifoldco/promptui/screenbuf/screenbuf.go | |
parent | 0b1a60ec27928a40ac827148c1517098612616bd (diff) | |
download | podman-8e4a42aa429c6dec0d5face7c69554d8a0677e96.tar.gz podman-8e4a42aa429c6dec0d5face7c69554d8a0677e96.tar.bz2 podman-8e4a42aa429c6dec0d5face7c69554d8a0677e96.zip |
short-name aliasing
Add support for short-name aliasing.
Signed-off-by: Valentin Rothberg <rothberg@redhat.com>
Diffstat (limited to 'vendor/github.com/manifoldco/promptui/screenbuf/screenbuf.go')
-rw-r--r-- | vendor/github.com/manifoldco/promptui/screenbuf/screenbuf.go | 151 |
1 files changed, 151 insertions, 0 deletions
diff --git a/vendor/github.com/manifoldco/promptui/screenbuf/screenbuf.go b/vendor/github.com/manifoldco/promptui/screenbuf/screenbuf.go new file mode 100644 index 000000000..861390045 --- /dev/null +++ b/vendor/github.com/manifoldco/promptui/screenbuf/screenbuf.go @@ -0,0 +1,151 @@ +package screenbuf + +import ( + "bytes" + "fmt" + "io" +) + +const esc = "\033[" + +var ( + clearLine = []byte(esc + "2K\r") + moveUp = []byte(esc + "1A") + moveDown = []byte(esc + "1B") +) + +// ScreenBuf is a convenient way to write to terminal screens. It creates, +// clears and, moves up or down lines as needed to write the output to the +// terminal using ANSI escape codes. +type ScreenBuf struct { + w io.Writer + buf *bytes.Buffer + reset bool + cursor int + height int +} + +// New creates and initializes a new ScreenBuf. +func New(w io.Writer) *ScreenBuf { + return &ScreenBuf{buf: &bytes.Buffer{}, w: w} +} + +// Reset truncates the underlining buffer and marks all its previous lines to be +// cleared during the next Write. +func (s *ScreenBuf) Reset() { + s.buf.Reset() + s.reset = true +} + +// Clear clears all previous lines and the output starts from the top. +func (s *ScreenBuf) Clear() error { + for i := 0; i < s.height; i++ { + _, err := s.buf.Write(moveUp) + if err != nil { + return err + } + _, err = s.buf.Write(clearLine) + if err != nil { + return err + } + } + s.cursor = 0 + s.height = 0 + s.reset = false + return nil +} + +// Write writes a single line to the underlining buffer. If the ScreenBuf was +// previously reset, all previous lines are cleared and the output starts from +// the top. Lines with \r or \n will cause an error since they can interfere with the +// terminal ability to move between lines. +func (s *ScreenBuf) Write(b []byte) (int, error) { + if bytes.ContainsAny(b, "\r\n") { + return 0, fmt.Errorf("%q should not contain either \\r or \\n", b) + } + + if s.reset { + if err := s.Clear(); err != nil { + return 0, err + } + } + + switch { + case s.cursor == s.height: + n, err := s.buf.Write(clearLine) + if err != nil { + return n, err + } + + n, err = s.buf.Write(b) + if err != nil { + return n, err + } + + _, err = s.buf.Write([]byte("\n")) + if err != nil { + return n, err + } + + s.height++ + s.cursor++ + return n, nil + case s.cursor < s.height: + n, err := s.buf.Write(clearLine) + if err != nil { + return n, err + } + n, err = s.buf.Write(b) + if err != nil { + return n, err + } + n, err = s.buf.Write(moveDown) + if err != nil { + return n, err + } + s.cursor++ + return n, nil + default: + return 0, fmt.Errorf("Invalid write cursor position (%d) exceeded line height: %d", s.cursor, s.height) + } +} + +// Flush writes any buffered data to the underlying io.Writer, ensuring that any pending data is displayed. +func (s *ScreenBuf) Flush() error { + for i := s.cursor; i < s.height; i++ { + if i < s.height { + _, err := s.buf.Write(clearLine) + if err != nil { + return err + } + } + _, err := s.buf.Write(moveDown) + if err != nil { + return err + } + } + + _, err := s.buf.WriteTo(s.w) + if err != nil { + return err + } + + s.buf.Reset() + + for i := 0; i < s.height; i++ { + _, err := s.buf.Write(moveUp) + if err != nil { + return err + } + } + + s.cursor = 0 + + return nil +} + +// WriteString is a convenient function to write a new line passing a string. +// Check ScreenBuf.Write() for a detailed explanation of the function behaviour. +func (s *ScreenBuf) WriteString(str string) (int, error) { + return s.Write([]byte(str)) +} |