125 lines
3 KiB
Go
125 lines
3 KiB
Go
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/*
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Copyright 2016 The Kubernetes Authors.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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package term
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import (
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"io"
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"os"
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"github.com/docker/docker/pkg/term"
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wordwrap "github.com/mitchellh/go-wordwrap"
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)
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type wordWrapWriter struct {
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limit uint
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writer io.Writer
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}
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// NewResponsiveWriter creates a Writer that detects the column width of the
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// terminal we are in, and adjusts every line width to fit and use recommended
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// terminal sizes for better readability. Does proper word wrapping automatically.
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// if terminal width >= 120 columns use 120 columns
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// if terminal width >= 100 columns use 100 columns
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// if terminal width >= 80 columns use 80 columns
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// In case we're not in a terminal or if it's smaller than 80 columns width,
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// doesn't do any wrapping.
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func NewResponsiveWriter(w io.Writer) io.Writer {
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file, ok := w.(*os.File)
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if !ok {
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return w
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}
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fd := file.Fd()
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if !term.IsTerminal(fd) {
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return w
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}
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terminalSize := GetSize(fd)
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if terminalSize == nil {
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return w
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}
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var limit uint
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switch {
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case terminalSize.Width >= 120:
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limit = 120
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case terminalSize.Width >= 100:
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limit = 100
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case terminalSize.Width >= 80:
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limit = 80
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}
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return NewWordWrapWriter(w, limit)
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}
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// NewWordWrapWriter is a Writer that supports a limit of characters on every line
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// and does auto word wrapping that respects that limit.
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func NewWordWrapWriter(w io.Writer, limit uint) io.Writer {
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return &wordWrapWriter{
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limit: limit,
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writer: w,
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}
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}
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func (w wordWrapWriter) Write(p []byte) (nn int, err error) {
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if w.limit == 0 {
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return w.writer.Write(p)
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}
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original := string(p)
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wrapped := wordwrap.WrapString(original, w.limit)
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return w.writer.Write([]byte(wrapped))
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}
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// NewPunchCardWriter is a NewWordWrapWriter that limits the line width to 80 columns.
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func NewPunchCardWriter(w io.Writer) io.Writer {
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return NewWordWrapWriter(w, 80)
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}
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type maxWidthWriter struct {
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maxWidth uint
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currentWidth uint
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written uint
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writer io.Writer
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}
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// NewMaxWidthWriter is a Writer that supports a limit of characters on every
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// line, but doesn't do any word wrapping automatically.
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func NewMaxWidthWriter(w io.Writer, maxWidth uint) io.Writer {
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return &maxWidthWriter{
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maxWidth: maxWidth,
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writer: w,
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}
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}
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func (m maxWidthWriter) Write(p []byte) (nn int, err error) {
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for _, b := range p {
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if m.currentWidth == m.maxWidth {
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m.writer.Write([]byte{'\n'})
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m.currentWidth = 0
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}
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if b == '\n' {
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m.currentWidth = 0
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}
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_, err := m.writer.Write([]byte{b})
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if err != nil {
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return int(m.written), err
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}
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m.written++
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m.currentWidth++
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}
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return len(p), nil
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}
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