mirror of https://github.com/kubernetes/kops.git
119 lines
2.6 KiB
Go
119 lines
2.6 KiB
Go
// Copyright (c) 2014-2019 TSUYUSATO Kitsune
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// This software is released under the MIT License.
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// http://opensource.org/licenses/mit-license.php
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// Package heredoc provides creation of here-documents from raw strings.
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//
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// Golang supports raw-string syntax.
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//
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// doc := `
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// Foo
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// Bar
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// `
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//
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// But raw-string cannot recognize indentation. Thus such content is an indented string, equivalent to
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//
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// "\n\tFoo\n\tBar\n"
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//
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// I dont't want this!
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//
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// However this problem is solved by package heredoc.
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//
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// doc := heredoc.Doc(`
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// Foo
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// Bar
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// `)
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//
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// Is equivalent to
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//
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// "Foo\nBar\n"
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package heredoc
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import (
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"fmt"
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"strings"
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)
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const maxInt = int(^uint(0) >> 1)
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// Doc returns un-indented string as here-document.
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func Doc(raw string) string {
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skipFirstLine := false
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if len(raw) > 0 && raw[0] == '\n' {
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raw = raw[1:]
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} else {
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skipFirstLine = true
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}
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lines := strings.Split(raw, "\n")
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minIndentSize := getMinIndent(lines, skipFirstLine)
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lines = removeIndentation(lines, minIndentSize, skipFirstLine)
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return strings.Join(lines, "\n")
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}
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// isSpace checks whether the rune represents space or not.
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// Only white spcaes (U+0020) and horizontal tabs are treated as space character.
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// It is the same as Go.
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//
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// See https://github.com/MakeNowJust/heredoc/issues/6#issuecomment-524231625.
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func isSpace(r rune) bool {
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switch r {
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case ' ', '\t':
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return true
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default:
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return false
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}
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}
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// getMinIndent calculates the minimum indentation in lines, excluding empty lines.
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func getMinIndent(lines []string, skipFirstLine bool) int {
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minIndentSize := maxInt
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for i, line := range lines {
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if i == 0 && skipFirstLine {
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continue
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}
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indentSize := 0
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for _, r := range line {
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if isSpace(r) {
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indentSize++
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} else {
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break
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}
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}
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if len(line) == indentSize {
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if i == len(lines)-1 && indentSize < minIndentSize {
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lines[i] = ""
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}
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} else if indentSize < minIndentSize {
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minIndentSize = indentSize
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}
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}
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return minIndentSize
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}
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// removeIndentation removes n characters from the front of each line in lines.
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// Skips first line if skipFirstLine is true, skips empty lines.
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func removeIndentation(lines []string, n int, skipFirstLine bool) []string {
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for i, line := range lines {
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if i == 0 && skipFirstLine {
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continue
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}
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if len(lines[i]) >= n {
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lines[i] = line[n:]
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}
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}
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return lines
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}
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// Docf returns unindented and formatted string as here-document.
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// Formatting is done as for fmt.Printf().
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func Docf(raw string, args ...interface{}) string {
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return fmt.Sprintf(Doc(raw), args...)
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}
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