v1.0.0

main/commands/base/command.go

@@ -0,0 +1,122 @@
+// Copyright 2017 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package base defines shared basic pieces of the commands,
+// in particular logging and the Command structure.
+package base
+
+import (
+	"flag"
+	"fmt"
+	"os"
+	"strings"
+	"sync"
+)
+
+// A Command is an implementation of a xray command
+// like xray run or xray version.
+type Command struct {
+	// Run runs the command.
+	// The args are the arguments after the command name.
+	Run func(cmd *Command, args []string)
+
+	// UsageLine is the one-line usage message.
+	// The words between "go" and the first flag or argument in the line are taken to be the command name.
+	UsageLine string
+
+	// Short is the short description shown in the 'go help' output.
+	Short string
+
+	// Long is the long message shown in the 'go help <this-command>' output.
+	Long string
+
+	// Flag is a set of flags specific to this command.
+	Flag flag.FlagSet
+
+	// CustomFlags indicates that the command will do its own
+	// flag parsing.
+	CustomFlags bool
+
+	// Commands lists the available commands and help topics.
+	// The order here is the order in which they are printed by 'go help'.
+	// Note that subcommands are in general best avoided.
+	Commands []*Command
+}
+
+// LongName returns the command's long name: all the words in the usage line between "go" and a flag or argument,
+func (c *Command) LongName() string {
+	name := c.UsageLine
+	if i := strings.Index(name, " ["); i >= 0 {
+		name = name[:i]
+	}
+	if name == CommandEnv.Exec {
+		return ""
+	}
+	return strings.TrimPrefix(name, CommandEnv.Exec+" ")
+}
+
+// Name returns the command's short name: the last word in the usage line before a flag or argument.
+func (c *Command) Name() string {
+	name := c.LongName()
+	if i := strings.LastIndex(name, " "); i >= 0 {
+		name = name[i+1:]
+	}
+	return name
+}
+
+// Usage prints usage of the Command
+func (c *Command) Usage() {
+	fmt.Fprintf(os.Stderr, "usage: %s\n", c.UsageLine)
+	fmt.Fprintf(os.Stderr, "Run 'xray help %s' for details.\n", c.LongName())
+	SetExitStatus(2)
+	Exit()
+}
+
+// Runnable reports whether the command can be run; otherwise
+// it is a documentation pseudo-command such as importpath.
+func (c *Command) Runnable() bool {
+	return c.Run != nil
+}
+
+// Exit exits with code set with SetExitStatus()
+func Exit() {
+	os.Exit(exitStatus)
+}
+
+// Fatalf logs error and exit with code 1
+func Fatalf(format string, args ...interface{}) {
+	Errorf(format, args...)
+	Exit()
+}
+
+// Errorf logs error and set exit status to 1, but not exit
+func Errorf(format string, args ...interface{}) {
+	fmt.Fprintf(os.Stderr, format, args...)
+	fmt.Fprintln(os.Stderr)
+	SetExitStatus(1)
+}
+
+// ExitIfErrors exits if current status is not zero
+func ExitIfErrors() {
+	if exitStatus != 0 {
+		Exit()
+	}
+}
+
+var exitStatus = 0
+var exitMu sync.Mutex
+
+// SetExitStatus set exit status code
+func SetExitStatus(n int) {
+	exitMu.Lock()
+	if exitStatus < n {
+		exitStatus = n
+	}
+	exitMu.Unlock()
+}
+
+// GetExitStatus get exit status code
+func GetExitStatus() int {
+	return exitStatus
+}