1 files changed, 335 insertions, 0 deletions
diff --git a/vendor/github.com/alexflint/go-arg/usage.go b/vendor/github.com/alexflint/go-arg/usage.go
new file mode 100644
index 0000000..e936811
--- /dev/null
+++ b/vendor/github.com/alexflint/go-arg/usage.go
@@ -0,0 +1,335 @@
+package arg
+
+import (
+	"fmt"
+	"io"
+	"os"
+	"strings"
+)
+
+// the width of the left column
+const colWidth = 25
+
+// to allow monkey patching in tests
+var (
+	stdout io.Writer = os.Stdout
+	stderr io.Writer = os.Stderr
+	osExit           = os.Exit
+)
+
+// Fail prints usage information to stderr and exits with non-zero status
+func (p *Parser) Fail(msg string) {
+	p.failWithSubcommand(msg, p.cmd)
+}
+
+// FailSubcommand prints usage information for a specified subcommand to stderr,
+// then exits with non-zero status. To write usage information for a top-level
+// subcommand, provide just the name of that subcommand. To write usage
+// information for a subcommand that is nested under another subcommand, provide
+// a sequence of subcommand names starting with the top-level subcommand and so
+// on down the tree.
+func (p *Parser) FailSubcommand(msg string, subcommand ...string) error {
+	cmd, err := p.lookupCommand(subcommand...)
+	if err != nil {
+		return err
+	}
+	p.failWithSubcommand(msg, cmd)
+	return nil
+}
+
+// failWithSubcommand prints usage information for the given subcommand to stderr and exits with non-zero status
+func (p *Parser) failWithSubcommand(msg string, cmd *command) {
+	p.writeUsageForSubcommand(stderr, cmd)
+	fmt.Fprintln(stderr, "error:", msg)
+	osExit(-1)
+}
+
+// WriteUsage writes usage information to the given writer
+func (p *Parser) WriteUsage(w io.Writer) {
+	cmd := p.cmd
+	if p.lastCmd != nil {
+		cmd = p.lastCmd
+	}
+	p.writeUsageForSubcommand(w, cmd)
+}
+
+// WriteUsageForSubcommand writes the usage information for a specified
+// subcommand. To write usage information for a top-level subcommand, provide
+// just the name of that subcommand. To write usage information for a subcommand
+// that is nested under another subcommand, provide a sequence of subcommand
+// names starting with the top-level subcommand and so on down the tree.
+func (p *Parser) WriteUsageForSubcommand(w io.Writer, subcommand ...string) error {
+	cmd, err := p.lookupCommand(subcommand...)
+	if err != nil {
+		return err
+	}
+	p.writeUsageForSubcommand(w, cmd)
+	return nil
+}
+
+// writeUsageForSubcommand writes usage information for the given subcommand
+func (p *Parser) writeUsageForSubcommand(w io.Writer, cmd *command) {
+	var positionals, longOptions, shortOptions []*spec
+	for _, spec := range cmd.specs {
+		switch {
+		case spec.positional:
+			positionals = append(positionals, spec)
+		case spec.long != "":
+			longOptions = append(longOptions, spec)
+		case spec.short != "":
+			shortOptions = append(shortOptions, spec)
+		}
+	}
+
+	if p.version != "" {
+		fmt.Fprintln(w, p.version)
+	}
+
+	// make a list of ancestor commands so that we print with full context
+	var ancestors []string
+	ancestor := cmd
+	for ancestor != nil {
+		ancestors = append(ancestors, ancestor.name)
+		ancestor = ancestor.parent
+	}
+
+	// print the beginning of the usage string
+	fmt.Fprint(w, "Usage:")
+	for i := len(ancestors) - 1; i >= 0; i-- {
+		fmt.Fprint(w, " "+ancestors[i])
+	}
+
+	// write the option component of the usage message
+	for _, spec := range shortOptions {
+		// prefix with a space
+		fmt.Fprint(w, " ")
+		if !spec.required {
+			fmt.Fprint(w, "[")
+		}
+		fmt.Fprint(w, synopsis(spec, "-"+spec.short))
+		if !spec.required {
+			fmt.Fprint(w, "]")
+		}
+	}
+
+	for _, spec := range longOptions {
+		// prefix with a space
+		fmt.Fprint(w, " ")
+		if !spec.required {
+			fmt.Fprint(w, "[")
+		}
+		fmt.Fprint(w, synopsis(spec, "--"+spec.long))
+		if !spec.required {
+			fmt.Fprint(w, "]")
+		}
+	}
+
+	// When we parse positionals, we check that:
+	//  1. required positionals come before non-required positionals
+	//  2. there is at most one multiple-value positional
+	//  3. if there is a multiple-value positional then it comes after all other positionals
+	// Here we merely print the usage string, so we do not explicitly re-enforce those rules
+
+	// write the positionals in following form:
+	//    REQUIRED1 REQUIRED2
+	//    REQUIRED1 REQUIRED2 [OPTIONAL1 [OPTIONAL2]]
+	//    REQUIRED1 REQUIRED2 REPEATED [REPEATED ...]
+	//    REQUIRED1 REQUIRED2 [REPEATEDOPTIONAL [REPEATEDOPTIONAL ...]]
+	//    REQUIRED1 REQUIRED2 [OPTIONAL1 [REPEATEDOPTIONAL [REPEATEDOPTIONAL ...]]]
+	var closeBrackets int
+	for _, spec := range positionals {
+		fmt.Fprint(w, " ")
+		if !spec.required {
+			fmt.Fprint(w, "[")
+			closeBrackets += 1
+		}
+		if spec.cardinality == multiple {
+			fmt.Fprintf(w, "%s [%s ...]", spec.placeholder, spec.placeholder)
+		} else {
+			fmt.Fprint(w, spec.placeholder)
+		}
+	}
+	fmt.Fprint(w, strings.Repeat("]", closeBrackets))
+
+	// if the program supports subcommands, give a hint to the user about their existence
+	if len(cmd.subcommands) > 0 {
+		fmt.Fprint(w, " <command> [<args>]")
+	}
+
+	fmt.Fprint(w, "\n")
+}
+
+func printTwoCols(w io.Writer, left, help string, defaultVal string, envVal string) {
+	lhs := "  " + left
+	fmt.Fprint(w, lhs)
+	if help != "" {
+		if len(lhs)+2 < colWidth {
+			fmt.Fprint(w, strings.Repeat(" ", colWidth-len(lhs)))
+		} else {
+			fmt.Fprint(w, "\n"+strings.Repeat(" ", colWidth))
+		}
+		fmt.Fprint(w, help)
+	}
+
+	bracketsContent := []string{}
+
+	if defaultVal != "" {
+		bracketsContent = append(bracketsContent,
+			fmt.Sprintf("default: %s", defaultVal),
+		)
+	}
+
+	if envVal != "" {
+		bracketsContent = append(bracketsContent,
+			fmt.Sprintf("env: %s", envVal),
+		)
+	}
+
+	if len(bracketsContent) > 0 {
+		fmt.Fprintf(w, " [%s]", strings.Join(bracketsContent, ", "))
+	}
+	fmt.Fprint(w, "\n")
+}
+
+// WriteHelp writes the usage string followed by the full help string for each option
+func (p *Parser) WriteHelp(w io.Writer) {
+	cmd := p.cmd
+	if p.lastCmd != nil {
+		cmd = p.lastCmd
+	}
+	p.writeHelpForSubcommand(w, cmd)
+}
+
+// WriteHelpForSubcommand writes the usage string followed by the full help
+// string for a specified subcommand. To write help for a top-level subcommand,
+// provide just the name of that subcommand. To write help for a subcommand that
+// is nested under another subcommand, provide a sequence of subcommand names
+// starting with the top-level subcommand and so on down the tree.
+func (p *Parser) WriteHelpForSubcommand(w io.Writer, subcommand ...string) error {
+	cmd, err := p.lookupCommand(subcommand...)
+	if err != nil {
+		return err
+	}
+	p.writeHelpForSubcommand(w, cmd)
+	return nil
+}
+
+// writeHelp writes the usage string for the given subcommand
+func (p *Parser) writeHelpForSubcommand(w io.Writer, cmd *command) {
+	var positionals, longOptions, shortOptions []*spec
+	for _, spec := range cmd.specs {
+		switch {
+		case spec.positional:
+			positionals = append(positionals, spec)
+		case spec.long != "":
+			longOptions = append(longOptions, spec)
+		case spec.short != "":
+			shortOptions = append(shortOptions, spec)
+		}
+	}
+
+	if p.description != "" {
+		fmt.Fprintln(w, p.description)
+	}
+	p.writeUsageForSubcommand(w, cmd)
+
+	// write the list of positionals
+	if len(positionals) > 0 {
+		fmt.Fprint(w, "\nPositional arguments:\n")
+		for _, spec := range positionals {
+			printTwoCols(w, spec.placeholder, spec.help, "", "")
+		}
+	}
+
+	// write the list of options with the short-only ones first to match the usage string
+	if len(shortOptions)+len(longOptions) > 0 || cmd.parent == nil {
+		fmt.Fprint(w, "\nOptions:\n")
+		for _, spec := range shortOptions {
+			p.printOption(w, spec)
+		}
+		for _, spec := range longOptions {
+			p.printOption(w, spec)
+		}
+	}
+
+	// obtain a flattened list of options from all ancestors
+	var globals []*spec
+	ancestor := cmd.parent
+	for ancestor != nil {
+		globals = append(globals, ancestor.specs...)
+		ancestor = ancestor.parent
+	}
+
+	// write the list of global options
+	if len(globals) > 0 {
+		fmt.Fprint(w, "\nGlobal options:\n")
+		for _, spec := range globals {
+			p.printOption(w, spec)
+		}
+	}
+
+	// write the list of built in options
+	p.printOption(w, &spec{
+		cardinality: zero,
+		long:        "help",
+		short:       "h",
+		help:        "display this help and exit",
+	})
+	if p.version != "" {
+		p.printOption(w, &spec{
+			cardinality: zero,
+			long:        "version",
+			help:        "display version and exit",
+		})
+	}
+
+	// write the list of subcommands
+	if len(cmd.subcommands) > 0 {
+		fmt.Fprint(w, "\nCommands:\n")
+		for _, subcmd := range cmd.subcommands {
+			printTwoCols(w, subcmd.name, subcmd.help, "", "")
+		}
+	}
+}
+
+func (p *Parser) printOption(w io.Writer, spec *spec) {
+	ways := make([]string, 0, 2)
+	if spec.long != "" {
+		ways = append(ways, synopsis(spec, "--"+spec.long))
+	}
+	if spec.short != "" {
+		ways = append(ways, synopsis(spec, "-"+spec.short))
+	}
+	if len(ways) > 0 {
+		printTwoCols(w, strings.Join(ways, ", "), spec.help, spec.defaultVal, spec.env)
+	}
+}
+
+// lookupCommand finds a subcommand based on a sequence of subcommand names. The
+// first string should be a top-level subcommand, the next should be a child
+// subcommand of that subcommand, and so on. If no strings are given then the
+// root command is returned. If no such subcommand exists then an error is
+// returned.
+func (p *Parser) lookupCommand(path ...string) (*command, error) {
+	cmd := p.cmd
+	for _, name := range path {
+		var found *command
+		for _, child := range cmd.subcommands {
+			if child.name == name {
+				found = child
+			}
+		}
+		if found == nil {
+			return nil, fmt.Errorf("%q is not a subcommand of %s", name, cmd.name)
+		}
+		cmd = found
+	}
+	return cmd, nil
+}
+
+func synopsis(spec *spec, form string) string {
+	if spec.cardinality == zero {
+		return form
+	}
+	return form + " " + spec.placeholder
+}