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// Copyright 2012 Jesse van den Kieboom. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package flags
import (
"bufio"
"bytes"
"fmt"
"io"
"runtime"
"strings"
"unicode/utf8"
)
type alignmentInfo struct {
maxLongLen int
hasShort bool
hasValueName bool
terminalColumns int
indent bool
}
const (
paddingBeforeOption = 2
distanceBetweenOptionAndDescription = 2
)
func (a *alignmentInfo) descriptionStart() int {
ret := a.maxLongLen + distanceBetweenOptionAndDescription
if a.hasShort {
ret += 2
}
if a.maxLongLen > 0 {
ret += 4
}
if a.hasValueName {
ret += 3
}
return ret
}
func (a *alignmentInfo) updateLen(name string, indent bool) {
l := utf8.RuneCountInString(name)
if indent {
l = l + 4
}
if l > a.maxLongLen {
a.maxLongLen = l
}
}
func (p *Parser) getAlignmentInfo() alignmentInfo {
ret := alignmentInfo{
maxLongLen: 0,
hasShort: false,
hasValueName: false,
terminalColumns: getTerminalColumns(),
}
if ret.terminalColumns <= 0 {
ret.terminalColumns = 80
}
var prevcmd *Command
p.eachActiveGroup(func(c *Command, grp *Group) {
if c != prevcmd {
for _, arg := range c.args {
ret.updateLen(arg.Name, c != p.Command)
}
}
for _, info := range grp.options {
if !info.canCli() {
continue
}
if info.ShortName != 0 {
ret.hasShort = true
}
if len(info.ValueName) > 0 {
ret.hasValueName = true
}
l := info.LongNameWithNamespace() + info.ValueName
if len(info.Choices) != 0 {
l += "[" + strings.Join(info.Choices, "|") + "]"
}
ret.updateLen(l, c != p.Command)
}
})
return ret
}
func wrapText(s string, l int, prefix string) string {
var ret string
if l < 10 {
l = 10
}
// Basic text wrapping of s at spaces to fit in l
lines := strings.Split(s, "\n")
for _, line := range lines {
var retline string
line = strings.TrimSpace(line)
for len(line) > l {
// Try to split on space
suffix := ""
pos := strings.LastIndex(line[:l], " ")
if pos < 0 {
pos = l - 1
suffix = "-\n"
}
if len(retline) != 0 {
retline += "\n" + prefix
}
retline += strings.TrimSpace(line[:pos]) + suffix
line = strings.TrimSpace(line[pos:])
}
if len(line) > 0 {
if len(retline) != 0 {
retline += "\n" + prefix
}
retline += line
}
if len(ret) > 0 {
ret += "\n"
if len(retline) > 0 {
ret += prefix
}
}
ret += retline
}
return ret
}
func (p *Parser) writeHelpOption(writer *bufio.Writer, option *Option, info alignmentInfo) {
line := &bytes.Buffer{}
prefix := paddingBeforeOption
if info.indent {
prefix += 4
}
if option.Hidden {
return
}
line.WriteString(strings.Repeat(" ", prefix))
if option.ShortName != 0 {
line.WriteRune(defaultShortOptDelimiter)
line.WriteRune(option.ShortName)
} else if info.hasShort {
line.WriteString(" ")
}
descstart := info.descriptionStart() + paddingBeforeOption
if len(option.LongName) > 0 {
if option.ShortName != 0 {
line.WriteString(", ")
} else if info.hasShort {
line.WriteString(" ")
}
line.WriteString(defaultLongOptDelimiter)
line.WriteString(option.LongNameWithNamespace())
}
if option.canArgument() {
line.WriteRune(defaultNameArgDelimiter)
if len(option.ValueName) > 0 {
line.WriteString(option.ValueName)
}
if len(option.Choices) > 0 {
line.WriteString("[" + strings.Join(option.Choices, "|") + "]")
}
}
written := line.Len()
line.WriteTo(writer)
if option.Description != "" {
dw := descstart - written
writer.WriteString(strings.Repeat(" ", dw))
var def string
if len(option.DefaultMask) != 0 {
if option.DefaultMask != "-" {
def = option.DefaultMask
}
} else {
def = option.defaultLiteral
}
var envDef string
if option.EnvDefaultKey != "" {
var envPrintable string
if runtime.GOOS == "windows" {
envPrintable = "%" + option.EnvDefaultKey + "%"
} else {
envPrintable = "$" + option.EnvDefaultKey
}
envDef = fmt.Sprintf(" [%s]", envPrintable)
}
var desc string
if def != "" {
desc = fmt.Sprintf("%s (default: %v)%s", option.Description, def, envDef)
} else {
desc = option.Description + envDef
}
writer.WriteString(wrapText(desc,
info.terminalColumns-descstart,
strings.Repeat(" ", descstart)))
}
writer.WriteString("\n")
}
func maxCommandLength(s []*Command) int {
if len(s) == 0 {
return 0
}
ret := len(s[0].Name)
for _, v := range s[1:] {
l := len(v.Name)
if l > ret {
ret = l
}
}
return ret
}
// WriteHelp writes a help message containing all the possible options and
// their descriptions to the provided writer. Note that the HelpFlag parser
// option provides a convenient way to add a -h/--help option group to the
// command line parser which will automatically show the help messages using
// this method.
func (p *Parser) WriteHelp(writer io.Writer) {
if writer == nil {
return
}
wr := bufio.NewWriter(writer)
aligninfo := p.getAlignmentInfo()
cmd := p.Command
for cmd.Active != nil {
cmd = cmd.Active
}
if p.Name != "" {
wr.WriteString("Usage:\n")
wr.WriteString(" ")
allcmd := p.Command
for allcmd != nil {
var usage string
if allcmd == p.Command {
if len(p.Usage) != 0 {
usage = p.Usage
} else if p.Options&HelpFlag != 0 {
usage = "[OPTIONS]"
}
} else if us, ok := allcmd.data.(Usage); ok {
usage = us.Usage()
} else if allcmd.hasCliOptions() {
usage = fmt.Sprintf("[%s-OPTIONS]", allcmd.Name)
}
if len(usage) != 0 {
fmt.Fprintf(wr, " %s %s", allcmd.Name, usage)
} else {
fmt.Fprintf(wr, " %s", allcmd.Name)
}
if len(allcmd.args) > 0 {
fmt.Fprintf(wr, " ")
}
for i, arg := range allcmd.args {
if i != 0 {
fmt.Fprintf(wr, " ")
}
name := arg.Name
if arg.isRemaining() {
name = name + "..."
}
if !allcmd.ArgsRequired {
fmt.Fprintf(wr, "[%s]", name)
} else {
fmt.Fprintf(wr, "%s", name)
}
}
if allcmd.Active == nil && len(allcmd.commands) > 0 {
var co, cc string
if allcmd.SubcommandsOptional {
co, cc = "[", "]"
} else {
co, cc = "<", ">"
}
visibleCommands := allcmd.visibleCommands()
if len(visibleCommands) > 3 {
fmt.Fprintf(wr, " %scommand%s", co, cc)
} else {
subcommands := allcmd.sortedVisibleCommands()
names := make([]string, len(subcommands))
for i, subc := range subcommands {
names[i] = subc.Name
}
fmt.Fprintf(wr, " %s%s%s", co, strings.Join(names, " | "), cc)
}
}
allcmd = allcmd.Active
}
fmt.Fprintln(wr)
if len(cmd.LongDescription) != 0 {
fmt.Fprintln(wr)
t := wrapText(cmd.LongDescription,
aligninfo.terminalColumns,
"")
fmt.Fprintln(wr, t)
}
}
c := p.Command
for c != nil {
printcmd := c != p.Command
c.eachGroup(func(grp *Group) {
first := true
// Skip built-in help group for all commands except the top-level
// parser
if grp.Hidden || (grp.isBuiltinHelp && c != p.Command) {
return
}
for _, info := range grp.options {
if !info.canCli() || info.Hidden {
continue
}
if printcmd {
fmt.Fprintf(wr, "\n[%s command options]\n", c.Name)
aligninfo.indent = true
printcmd = false
}
if first && cmd.Group != grp {
fmt.Fprintln(wr)
if aligninfo.indent {
wr.WriteString(" ")
}
fmt.Fprintf(wr, "%s:\n", grp.ShortDescription)
first = false
}
p.writeHelpOption(wr, info, aligninfo)
}
})
var args []*Arg
for _, arg := range c.args {
if arg.Description != "" {
args = append(args, arg)
}
}
if len(args) > 0 {
if c == p.Command {
fmt.Fprintf(wr, "\nArguments:\n")
} else {
fmt.Fprintf(wr, "\n[%s command arguments]\n", c.Name)
}
descStart := aligninfo.descriptionStart() + paddingBeforeOption
for _, arg := range args {
argPrefix := strings.Repeat(" ", paddingBeforeOption)
argPrefix += arg.Name
if len(arg.Description) > 0 {
argPrefix += ":"
wr.WriteString(argPrefix)
// Space between "arg:" and the description start
descPadding := strings.Repeat(" ", descStart-len(argPrefix))
// How much space the description gets before wrapping
descWidth := aligninfo.terminalColumns - 1 - descStart
// Whitespace to which we can indent new description lines
descPrefix := strings.Repeat(" ", descStart)
wr.WriteString(descPadding)
wr.WriteString(wrapText(arg.Description, descWidth, descPrefix))
} else {
wr.WriteString(argPrefix)
}
fmt.Fprintln(wr)
}
}
c = c.Active
}
scommands := cmd.sortedVisibleCommands()
if len(scommands) > 0 {
maxnamelen := maxCommandLength(scommands)
fmt.Fprintln(wr)
fmt.Fprintln(wr, "Available commands:")
for _, c := range scommands {
fmt.Fprintf(wr, " %s", c.Name)
if len(c.ShortDescription) > 0 {
pad := strings.Repeat(" ", maxnamelen-len(c.Name))
fmt.Fprintf(wr, "%s %s", pad, c.ShortDescription)
if len(c.Aliases) > 0 {
fmt.Fprintf(wr, " (aliases: %s)", strings.Join(c.Aliases, ", "))
}
}
fmt.Fprintln(wr)
}
}
wr.Flush()
}