commands/cli: Added a helptext generator

cli/helptext.go

+package cli
+
+import (
+	"fmt"
+	"strings"
+
+	cmds "github.com/jbenet/go-ipfs/commands"
+)
+
+const (
+	requiredArg = "<%v>"
+	optionalArg = "[<%v>]"
+	variadicArg = "%v..."
+	optionFlag  = "-%v"
+	optionType  = "(%v)"
+
+	whitespace = "\r\n\t "
+)
+
+// HelpText returns a formatted CLI helptext string, generated for the given command
+func HelpText(rootName string, root *cmds.Command, path []string) (string, error) {
+	cmd, err := root.Get(path)
+	if err != nil {
+		return "", err
+	}
+
+	s := ""
+	usage := usageText(cmd)
+	if len(usage) > 0 {
+		usage += " "
+	}
+	s += fmt.Sprintf("%v %v %v- %v\n\n", rootName, strings.Join(path, " "), usage, cmd.Description)
+
+	if len(cmd.Help) > 0 {
+		s += fmt.Sprintf("%v\n\n", strings.Trim(cmd.Help, whitespace))
+	}
+
+	if cmd.Arguments != nil {
+		lines := indent(argumentText(cmd), "  ")
+		s += fmt.Sprintf("Arguments:\n%v\n\n", strings.Join(lines, "\n"))
+	}
+
+	if cmd.Subcommands != nil {
+		lines := indent(subcommandText(cmd, rootName, path), "  ")
+		s += fmt.Sprintf("Subcommands:\n%v\n\n", strings.Join(lines, "\n"))
+	}
+
+	if cmd.Options != nil {
+		lines := indent(optionText(cmd), "  ")
+		s += fmt.Sprintf("Options:\n%v\n\n", strings.Join(lines, "\n"))
+	}
+
+	return s, nil
+}
+
+func argumentText(cmd *cmds.Command) []string {
+	lines := make([]string, len(cmd.Arguments))
+
+	for i, arg := range cmd.Arguments {
+		lines[i] = argUsageText(arg)
+		lines[i] += "\n" + arg.Description
+		lines[i] = indentString(lines[i], "    ") + "\n"
+	}
+
+	return lines
+}
+
+func optionText(cmd ...*cmds.Command) []string {
+	// get a slice of the options we want to list out
+	options := make([]cmds.Option, 0)
+	for _, c := range cmd {
+		for _, opt := range c.Options {
+			options = append(options, opt)
+		}
+	}
+
+	// add option names to output (with each name aligned)
+	lines := make([]string, 0)
+	j := 0
+	for {
+		done := true
+		i := 0
+		for _, opt := range options {
+			if len(lines) < i+1 {
+				lines = append(lines, "")
+			}
+			if len(opt.Names) >= j+1 {
+				lines[i] += fmt.Sprintf(optionFlag, opt.Names[j])
+			}
+			if len(opt.Names) > j+1 {
+				lines[i] += ", "
+				done = false
+			}
+
+			i++
+		}
+
+		if done {
+			break
+		}
+
+		lines = align(lines)
+		j++
+	}
+
+	// add option types to output
+	for i, opt := range options {
+		lines[i] += " " + fmt.Sprintf(optionType, opt.Type)
+	}
+	lines = align(lines)
+
+	// add option descriptions to output
+	for i, opt := range options {
+		lines[i] += "\n" + opt.Description
+		lines[i] = indentString(lines[i], "    ") + "\n"
+	}
+
+	return lines
+}
+
+func subcommandText(cmd *cmds.Command, rootName string, path []string) []string {
+	prefix := fmt.Sprintf("%v %v", rootName, strings.Join(path, " "))
+	lines := make([]string, len(cmd.Subcommands))
+
+	i := 0
+	for name, sub := range cmd.Subcommands {
+		usage := usageText(sub)
+		lines[i] = fmt.Sprintf("%v %v %v", prefix, name, usage)
+		lines[i] += fmt.Sprintf("\n%v", sub.Description)
+		lines[i] = indentString(lines[i], "    ") + "\n"
+		i++
+	}
+
+	return lines
+}
+
+func usageText(cmd *cmds.Command) string {
+	s := ""
+	for i, arg := range cmd.Arguments {
+		if i != 0 {
+			s += " "
+		}
+		s += argUsageText(arg)
+	}
+
+	return s
+}
+
+func argUsageText(arg cmds.Argument) string {
+	s := arg.Name
+
+	if arg.Required {
+		s = fmt.Sprintf(requiredArg, s)
+	} else {
+		s = fmt.Sprintf(optionalArg, s)
+	}
+
+	if arg.Variadic {
+		s = fmt.Sprintf(variadicArg, s)
+	}
+
+	return s
+}
+
+func align(lines []string) []string {
+	longest := 0
+	for _, line := range lines {
+		length := len(line)
+		if length > longest {
+			longest = length
+		}
+	}
+
+	for i, line := range lines {
+		length := len(line)
+		if length > 0 {
+			lines[i] += strings.Repeat(" ", longest-length)
+		}
+	}
+
+	return lines
+}
+
+func indent(lines []string, prefix string) []string {
+	for i, line := range lines {
+		lines[i] = prefix + indentString(line, prefix)
+	}
+	return lines
+}
+
+func indentString(line string, prefix string) string {
+	return strings.Replace(line, "\n", "\n"+prefix, -1)
+}