Add easy way to install the bash completion

cmd.go

@@ -0,0 +1,87 @@
+package complete
+
+import (
+	"errors"
+	"flag"
+	"fmt"
+	"os"
+	"strings"
+
+	"github.com/posener/complete/install"
+)
+
+func runCommandLine(cmd string) {
+	c := parseFlags(cmd)
+	err := c.validate()
+	if err != nil {
+		os.Stderr.WriteString(err.Error() + "\n")
+		os.Exit(1)
+	}
+	if !c.yes && !prompt(c.action(), cmd) {
+		fmt.Println("Cancelling...")
+		os.Exit(2)
+	}
+	fmt.Println(c.action() + "ing...")
+	if c.install {
+		err = install.Install(cmd, c.root)
+	} else {
+		err = install.Uninstall(cmd, c.root)
+	}
+	if err != nil {
+		fmt.Printf("%s failed! %s\n", c.action(), err)
+		os.Exit(3)
+	}
+	fmt.Println("Done!")
+}
+
+func prompt(action, cmd string) bool {
+	fmt.Printf("%s bash completion for %s? ", action, cmd)
+	var answer string
+	fmt.Scanln(&answer)
+
+	switch strings.ToLower(answer) {
+	case "y", "yes":
+		return true
+	default:
+		return false
+	}
+}
+
+type config struct {
+	install   bool
+	uninstall bool
+	root      bool
+	yes       bool
+}
+
+func parseFlags(cmd string) config {
+	var c config
+	flag.BoolVar(&c.install, "install", false,
+		fmt.Sprintf("Install bash completion for %s command", cmd))
+	flag.BoolVar(&c.uninstall, "uninstall", false,
+		fmt.Sprintf("Uninstall bash completion for %s command", cmd))
+	flag.BoolVar(&c.root, "root", false,
+		"(Un)Install as root:\n"+
+			"            (Un)Install at /etc/bash_completion.d/ (user should have write permissions to that directory).\n"+
+			"            If not set, a complete command will be added(removed) to ~/.bashrc")
+	flag.BoolVar(&c.yes, "y", false, "Don't prompt user for typing 'yes'")
+	flag.Parse()
+	return c
+}
+
+func (c config) validate() error {
+	if c.install && c.uninstall {
+		return errors.New("Install and uninstall are exclusive")
+	}
+	if !c.install && !c.uninstall {
+		return errors.New("Must specify -install or -uninstall")
+	}
+	return nil
+}
+
+func (c config) action() string {
+	if c.install {
+		return "Install"
+	}
+	return "Uninstall"
+}

command.go

@@ -5,6 +5,7 @@ type Commands map[string]Command
 type Flags map[string]Predicate
 
 type Command struct {
+	Name  string
 	Sub   Commands
 	Flags Flags
 	Args  Predicate

gocomplete/complete.go

@@ -164,6 +164,7 @@ func main() {
 	}
 
 	gogo := complete.Command{
+		Name: "go",
 		Sub: complete.Commands{
 			"build":    build,
 			"install":  build, // install and build have the same flags

install/home.go

@@ -0,0 +1,153 @@
+package install
+
+import (
+	"bufio"
+	"errors"
+	"fmt"
+	"io"
+	"os"
+	"os/user"
+	"path/filepath"
+	"io/ioutil"
+)
+
+type home struct{}
+
+func (home) Install(cmd, bin string) error {
+	bashRCFileName, err := bashRCFileName()
+	if err != nil {
+		return err
+	}
+	completeCmd := completeCmd(cmd, bin)
+	if isInFile(bashRCFileName, completeCmd) {
+		return errors.New("Already installed in ~/.bashrc")
+	}
+
+	bashRC, err := os.OpenFile(bashRCFileName, os.O_RDWR|os.O_APPEND, 0)
+	if err != nil {
+		return err
+	}
+	defer bashRC.Close()
+	_, err = bashRC.WriteString(fmt.Sprintf("\n%s\n", completeCmd))
+	return err
+}
+
+func (home) Uninstall(cmd, bin string) error {
+	bashRC, err := bashRCFileName()
+	if err != nil {
+		return err
+	}
+	backup := bashRC + ".bck"
+	err = copyFile(bashRC, backup)
+	if err != nil {
+		return err
+	}
+	completeCmd := completeCmd(cmd, bin)
+	if !isInFile(bashRC, completeCmd) {
+		return errors.New("Does not installed in ~/.bashrc")
+	}
+	temp, err := uninstallToTemp(bashRC, completeCmd)
+	if err != nil {
+		return err
+	}
+
+	err = copyFile(temp, bashRC)
+	if err != nil {
+		return err
+	}
+
+	return os.Remove(backup)
+}
+
+func completeCmd(cmd, bin string) string {
+	return fmt.Sprintf("complete -C %s %s", bin, cmd)
+}
+
+func bashRCFileName() (string, error) {
+	u, err := user.Current()
+	if err != nil {
+		return "", err
+	}
+	return filepath.Join(u.HomeDir, ".bashrc"), nil
+}
+
+func isInFile(name string, lookFor string) bool {
+	f, err := os.Open(name)
+	if err != nil {
+		return false
+	}
+	defer f.Close()
+	r := bufio.NewReader(f)
+	prefix := []byte{}
+	for {
+		line, isPrefix, err := r.ReadLine()
+		if err == io.EOF {
+			return false
+		}
+		if err != nil {
+			return false
+		}
+		if isPrefix {
+			prefix = append(prefix, line...)
+			continue
+		}
+		line = append(prefix, line...)
+		if string(line) == lookFor {
+			return true
+		}
+		prefix = prefix[:0]
+	}
+	return false
+}
+
+func uninstallToTemp(bashRCFileName, completeCmd string) (string, error) {
+	rf, err := os.Open(bashRCFileName)
+	if err != nil {
+		return "", err
+	}
+	defer rf.Close()
+	wf, err := ioutil.TempFile("/tmp", "bashrc-")
+	if err != nil {
+		return "", err
+	}
+	defer wf.Close()
+
+	r := bufio.NewReader(rf)
+	prefix := []byte{}
+	for {
+		line, isPrefix, err := r.ReadLine()
+		if err == io.EOF {
+			break
+		}
+		if err != nil {
+			return "", err
+		}
+		if isPrefix {
+			prefix = append(prefix, line...)
+			continue
+		}
+		line = append(prefix, line...)
+		str := string(line)
+		if str == completeCmd {
+			continue
+		}
+		wf.WriteString(str + "\n")
+		prefix = prefix[:0]
+	}
+	return wf.Name(), nil
+}
+
+func copyFile(src string, dst string) error {
+	in, err := os.Open(src)
+	if err != nil {
+		return err
+	}
+	defer in.Close()
+	out, err := os.Create(dst)
+	if err != nil {
+		return err
+	}
+	defer out.Close()
+	_, err = io.Copy(out, in)
+	return err
+}

install/install.go

@@ -0,0 +1,43 @@
+package install
+
+import (
+	"os"
+	"path/filepath"
+)
+
+type installer interface {
+	Install(cmd, bin string) error
+	Uninstall(cmd, bin string) error
+}
+
+func Install(cmd string, asRoot bool) error {
+	bin, err := getBinaryPath()
+	if err != nil {
+		return err
+	}
+	return getInstaller(asRoot).Install(cmd, bin)
+}
+
+func Uninstall(cmd string, asRoot bool) error {
+	bin, err := getBinaryPath()
+	if err != nil {
+		return err
+	}
+	return getInstaller(asRoot).Uninstall(cmd, bin)
+}
+
+func getInstaller(asRoot bool) installer {
+	if asRoot {
+		return root{}
+	} else {
+		return home{}
+	}
+}
+
+func getBinaryPath() (string, error) {
+	bin, err := os.Executable()
+	if err != nil {
+		return "", err
+	}
+	return filepath.Abs(bin)
+}

install/root.go

@@ -0,0 +1,30 @@
+package install
+
+import "os"
+
+type root struct{}
+
+func (r root) Install(cmd string, bin string) error {
+	completeLink := getBashCompletionDLink(cmd)
+	err := r.Uninstall(cmd, bin)
+	if err != nil {
+		return err
+	}
+	return os.Symlink(bin, completeLink)
+}
+
+func (root) Uninstall(cmd string, bin string) error {
+	completeLink := getBashCompletionDLink(cmd)
+	if _, err := os.Stat(completeLink); err == nil {
+		err := os.Remove(completeLink)
+		if err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+func getBashCompletionDLink(cmd string) string {
+	return "/etc/bash_completion.d/"+cmd
+}
+

readme.md

@@ -5,20 +5,25 @@
 
 WIP
 
-a tool for bash writing bash completion in go.
+A tool for bash writing bash completion in go.
 
-## example: `go` command bash completion
+Writing bash completion scripts is a hard work. This package provides an easy way
+to create bash completion scripts for any command, and also an easy way to install/uninstall
+the completion of the command.
 
-Install in you home directory:
+## go command bash completion
+
+In [gocomplete](./gocomplete) there is an example for bash completion for the `go` command line.
+
+### Install
 
 ```
-go build -o ~/.bash_completion/go ./gocomplete
-echo "complete -C ~/.bash_completion/go go" >> ~/.bashrc
+go get github.com/posener/complete/gocomplete
+gocomplete -install
 ```
 
-Or, install in the root directory:
+### Uninstall
 
 ```
-sudo go build -o /etc/bash_completion.d/go ./gocomplete
+gocomplete -uninstall
 ```
-

run.go

@@ -14,7 +14,11 @@ const (
 // Run get a command, get the typed arguments from environment
 // variable, and print out the complete options
 func Run(c Command) {
-	args := getLine()
+	args, ok := getLine()
+	if !ok {
+		runCommandLine(c.Name)
+		return
+	}
 	Log("Completing args: %s", args)
 
 	options := complete(c, args)
@@ -38,12 +42,12 @@ func complete(c Command, args []string) (matching []string) {
 	return
 }
 
-func getLine() []string {
+func getLine() ([]string, bool) {
 	line := os.Getenv(envComplete)
 	if line == "" {
-		panic("should be run as a complete script")
+		return nil, false
 	}
-	return strings.Split(line, " ")
+	return strings.Split(line, " "), true
 }
 
 func last(args []string) (last string) {

run_test.go

@@ -177,7 +177,7 @@ func TestCompleter_Complete(t *testing.T) {
 
 			tt.args = "cmd " + tt.args
 			os.Setenv(envComplete, tt.args)
-			args := getLine()
+			args, _ := getLine()
 
 			got := complete(c, args)