moving to go style commands

git-svn-id: https://weed-fs.googlecode.com/svn/trunk@62 282b0af5-e82d-9cf1-ede4-77906d7719d0

weed-fs/src/cmd/weed/command.go

@@ -0,0 +1,53 @@
+package main
+
+import (
+  "flag"
+  "fmt"
+  "os"
+  "strings"
+)
+
+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 first word in the line is 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
+}
+
+// Name returns the command's name: the first word in the usage line.
+func (c *Command) Name() string {
+  name := c.UsageLine
+  i := strings.Index(name, " ")
+  if i >= 0 {
+    name = name[:i]
+  }
+  return name
+}
+
+func (c *Command) Usage() {
+  fmt.Fprintf(os.Stderr, "usage: %s\n\n", c.UsageLine)
+  fmt.Fprintf(os.Stderr, "%s\n", strings.TrimSpace(c.Long))
+  os.Exit(2)
+}
+
+// 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
+}

weed-fs/src/cmd/weed/version.go

@@ -0,0 +1,25 @@
+// Copyright 2011 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 main
+
+import (
+	"fmt"
+	"runtime"
+)
+
+var cmdVersion = &Command{
+	Run:       runVersion,
+	UsageLine: "version",
+	Short:     "print Weed File System version",
+	Long:      `Version prints the Weed File System version`,
+}
+
+func runVersion(cmd *Command, args []string) {
+	if len(args) != 0 {
+		cmd.Usage()
+	}
+
+	fmt.Printf("version 0.15 %s %s\n",runtime.GOOS, runtime.GOARCH)
+}

weed-fs/src/cmd/weed/weed.go

@@ -0,0 +1,190 @@
+package main
+
+import (
+	"flag"
+	"fmt"
+	"io"
+	"log"
+	"os"
+	"strings"
+	"sync"
+	"text/template"
+	"unicode"
+	"unicode/utf8"
+)
+
+var commands = []*Command{
+	cmdVersion,
+}
+
+var exitStatus = 0
+var exitMu sync.Mutex
+
+func setExitStatus(n int) {
+	exitMu.Lock()
+	if exitStatus < n {
+		exitStatus = n
+	}
+	exitMu.Unlock()
+}
+
+func main() {
+	flag.Usage = usage
+	flag.Parse()
+	log.SetFlags(0)
+
+	args := flag.Args()
+	if len(args) < 1 {
+		usage()
+	}
+
+	if args[0] == "help" {
+		help(args[1:])
+		return
+	}
+
+	for _, cmd := range commands {
+		if cmd.Name() == args[0] && cmd.Run != nil {
+			cmd.Flag.Usage = func() { cmd.Usage() }
+			if cmd.CustomFlags {
+				args = args[1:]
+			} else {
+				cmd.Flag.Parse(args[1:])
+				args = cmd.Flag.Args()
+			}
+			cmd.Run(cmd, args)
+			exit()
+			return
+		}
+	}
+
+	fmt.Fprintf(os.Stderr, "weed: unknown subcommand %q\nRun 'weed help' for usage.\n", args[0])
+	setExitStatus(2)
+	exit()
+}
+
+var usageTemplate = `Go is a tool for managing Go source code.
+
+Usage:
+
+	weed command [arguments]
+
+The commands are:
+{{range .}}{{if .Runnable}}
+    {{.Name | printf "%-11s"}} {{.Short}}{{end}}{{end}}
+
+Use "weed help [command]" for more information about a command.
+
+Additional help topics:
+{{range .}}{{if not .Runnable}}
+    {{.Name | printf "%-11s"}} {{.Short}}{{end}}{{end}}
+
+Use "weed help [topic]" for more information about that topic.
+
+`
+
+var helpTemplate = `{{if .Runnable}}usage: weed {{.UsageLine}}
+
+{{end}}{{.Long | trim}}
+`
+
+// tmpl executes the given template text on data, writing the result to w.
+func tmpl(w io.Writer, text string, data interface{}) {
+	t := template.New("top")
+	t.Funcs(template.FuncMap{"trim": strings.TrimSpace, "capitalize": capitalize})
+	template.Must(t.Parse(text))
+	if err := t.Execute(w, data); err != nil {
+		panic(err)
+	}
+}
+
+func capitalize(s string) string {
+	if s == "" {
+		return s
+	}
+	r, n := utf8.DecodeRuneInString(s)
+	return string(unicode.ToTitle(r)) + s[n:]
+}
+
+func printUsage(w io.Writer) {
+	tmpl(w, usageTemplate, commands)
+}
+
+func usage() {
+	printUsage(os.Stderr)
+	os.Exit(2)
+}
+
+// help implements the 'help' command.
+func help(args []string) {
+	if len(args) == 0 {
+		printUsage(os.Stdout)
+		// not exit 2: succeeded at 'weed help'.
+		return
+	}
+	if len(args) != 1 {
+		fmt.Fprintf(os.Stderr, "usage: weed help command\n\nToo many arguments given.\n")
+		os.Exit(2) // failed at 'weed help'
+	}
+
+	arg := args[0]
+
+	for _, cmd := range commands {
+		if cmd.Name() == arg {
+			tmpl(os.Stdout, helpTemplate, cmd)
+			// not exit 2: succeeded at 'weed help cmd'.
+			return
+		}
+	}
+
+	fmt.Fprintf(os.Stderr, "Unknown help topic %#q.  Run 'weed help'.\n", arg)
+	os.Exit(2) // failed at 'weed help cmd'
+}
+
+var atexitFuncs []func()
+
+func atexit(f func()) {
+	atexitFuncs = append(atexitFuncs, f)
+}
+
+func exit() {
+	for _, f := range atexitFuncs {
+		f()
+	}
+	os.Exit(exitStatus)
+}
+
+func fatalf(format string, args ...interface{}) {
+	errorf(format, args...)
+	exit()
+}
+
+func errorf(format string, args ...interface{}) {
+	log.Printf(format, args...)
+	setExitStatus(1)
+}
+
+var logf = log.Printf
+
+func exitIfErrors() {
+	if exitStatus != 0 {
+		exit()
+	}
+}
+
+// stringList's arguments should be a sequence of string or []string values.
+// stringList flattens them into a single []string.
+func stringList(args ...interface{}) []string {
+	var x []string
+	for _, arg := range args {
+		switch arg := arg.(type) {
+		case []string:
+			x = append(x, arg...)
+		case string:
+			x = append(x, arg)
+		default:
+			panic("stringList: invalid argument")
+		}
+	}
+	return x
+}