implement :cd, :chdir, :pwd commands to change the working directory

README.md

@@ -48,6 +48,8 @@ So if you have experience with Vim, you will notice most of basic operations of
 
 - File operations
   - `:edit`, `:enew`, `:new`, `:vnew`, `:only`
+- Current working directory
+  - `:cd`, `:chdir`, `:pwd`
 - Quit and save
   - `:quit`, `:qall`, `:write`, `:wq`, `:xit`, `:xall`, `:cquit`
 - Window operations

cmdline/command.go

@@ -21,6 +21,9 @@ var commands = []command{
 	{"u[ndo]", event.Undo},
 	{"red[o]", event.Redo},
 
+	{"pw[d]", event.PrintDirectory},
+	{"cd", event.ChangeDirectory},
+	{"chd[ir]", event.ChangeDirectory},
 	{"exi[t]", event.Quit},
 	{"q[uit]", event.Quit},
 	{"qa[ll]", event.QuitAll},

cmdline/completor.go

@@ -31,7 +31,9 @@ func (c *completor) clear() {
 func (c *completor) complete(cmdline string, cmd command, prefix string, arg string, forward bool) string {
 	switch cmd.eventType {
 	case event.Edit, event.New, event.Vnew, event.Write:
-		return c.completeFilepaths(cmdline, prefix, arg, forward)
+		return c.completeFilepaths(cmdline, prefix, arg, forward, false)
+	case event.ChangeDirectory:
+		return c.completeFilepaths(cmdline, prefix, arg, forward, true)
 	case event.Wincmd:
 		return c.completeWincmd(cmdline, prefix, arg, forward)
 	default:
@@ -53,7 +55,9 @@ func (c *completor) completeNext(prefix string, forward bool) string {
 	return prefix + c.arg + c.results[c.index]
 }
 
-func (c *completor) completeFilepaths(cmdline string, prefix string, arg string, forward bool) string {
+func (c *completor) completeFilepaths(
+	cmdline string, prefix string, arg string, forward bool, dirOnly bool,
+) string {
 	if !strings.HasSuffix(prefix, " ") {
 		prefix += " "
 	}
@@ -62,7 +66,7 @@ func (c *completor) completeFilepaths(cmdline string, prefix string, arg string,
 	}
 	c.target = cmdline
 	c.index = 0
-	c.arg, c.results = c.listFileNames(arg)
+	c.arg, c.results = c.listFileNames(arg, dirOnly)
 	if len(c.results) == 1 {
 		cmdline := prefix + c.arg + c.results[0]
 		c.results = nil
@@ -81,7 +85,7 @@ func (c *completor) completeFilepaths(cmdline string, prefix string, arg string,
 
 const separator = string(filepath.Separator)
 
-func (c *completor) listFileNames(arg string) (string, []string) {
+func (c *completor) listFileNames(arg string, dirOnly bool) (string, []string) {
 	var targets []string
 	path, homedir, hasHomedirPrefix, err := expandHomedir(arg)
 	if err != nil {
@@ -132,6 +136,8 @@ func (c *completor) listFileNames(arg string) (string, []string) {
 		}
 		if isDir {
 			name += separator
+		} else if dirOnly {
+			continue
 		}
 		targets = append(targets, name)
 	}

cmdline/completor_test.go

@@ -255,6 +255,40 @@ func TestCompletorCompleteFilepathRoot(t *testing.T) {
 	}
 }
 
+func TestCompletorCompleteFilepathChangeDirectory(t *testing.T) {
+	c := newCompletor(&mockFilesystem{})
+	cmdline := "cd "
+	cmd, _, prefix, _, arg, _ := parse([]rune(cmdline))
+	cmdline = c.complete(cmdline, cmd, prefix, arg, false)
+	if expected := "cd editor/"; cmdline != expected {
+		t.Errorf("cmdline should be %q but got %q", expected, cmdline)
+	}
+	if expected := "cd "; c.target != expected {
+		t.Errorf("completion target should be %q but got %q", expected, c.target)
+	}
+	if c.index != 3 {
+		t.Errorf("completion index should be %d but got %d", 3, c.index)
+	}
+
+	c.clear()
+	cmdline = c.complete(cmdline, cmd, prefix, "~/", false)
+	if expected := "cd ~/Pictures/"; cmdline != expected {
+		t.Errorf("cmdline should be %q but got %q", expected, cmdline)
+	}
+	if c.index != 2 {
+		t.Errorf("completion index should be %d but got %d", 0, c.index)
+	}
+
+	c.clear()
+	cmdline = c.complete(cmdline, cmd, prefix, "/", true)
+	if expected := "cd /bin/"; cmdline != expected {
+		t.Errorf("cmdline should be %q but got %q", expected, cmdline)
+	}
+	if c.index != 0 {
+		t.Errorf("completion index should be %d but got %d", 0, c.index)
+	}
+}
+
 func TestCompletorCompleteWincmd(t *testing.T) {
 	c := newCompletor(&mockFilesystem{})
 	cmdline := "winc"

editor/editor.go

@@ -4,6 +4,8 @@ import (
 	"errors"
 	"fmt"
 	"io"
+	"os"
+	"path/filepath"
 	"strconv"
 	"strings"
 	"sync"
@@ -24,6 +26,7 @@ type Editor struct {
 	searchTarget  string
 	searchMode    rune
 	prevEventType event.Type
+	prevDir       string
 	buffer        *buffer.Buffer
 	err           error
 	errtyp        int
@@ -147,7 +150,7 @@ func (e *Editor) emit(ev event.Event) (redraw bool, finish bool, err error) {
 	}
 	switch ev.Type {
 	case event.QuitAll:
-		if len(ev.Arg) > 0 {
+		if ev.Arg != "" {
 			e.err, e.errtyp = errors.New("too many arguments for "+ev.CmdName), state.MessageError
 			redraw = true
 		} else {
@@ -171,8 +174,35 @@ func (e *Editor) emit(ev event.Event) (redraw bool, finish bool, err error) {
 			err = &quitErr{1}
 			finish = true
 		}
+	case event.PrintDirectory:
+		if ev.Arg != "" {
+			e.err, e.errtyp = errors.New("too many arguments for "+ev.CmdName), state.MessageError
+			redraw = true
+			break
+		}
+		fallthrough
+	case event.ChangeDirectory:
+		if ev.Arg == "-" && e.prevDir == "" {
+			e.err, e.errtyp = errors.New("no previous working directory"), state.MessageError
+		} else if dir, err := os.Getwd(); err != nil {
+			e.err, e.errtyp = err, state.MessageError
+		} else if ev.Arg == "" {
+			e.err, e.errtyp = errors.New(dir), state.MessageInfo
+		} else {
+			if ev.Arg != "-" {
+				dir, e.prevDir = ev.Arg, dir
+			} else {
+				dir, e.prevDir = e.prevDir, dir
+			}
+			if dir, err = e.chdir(dir); err != nil {
+				e.err, e.errtyp = err, state.MessageError
+			} else {
+				e.err, e.errtyp = errors.New(dir), state.MessageInfo
+			}
+		}
+		redraw = true
 	case event.Suspend:
-		if len(ev.Arg) > 0 {
+		if ev.Arg != "" {
 			e.err, e.errtyp = errors.New("too many arguments for "+ev.CmdName), state.MessageError
 		} else {
 			e.mu.Unlock()
@@ -340,6 +370,18 @@ func (e *Editor) redraw() (err error) {
 	return e.ui.Redraw(s)
 }
 
+func (e *Editor) chdir(dir string) (string, error) {
+	if dir, err := expandHomedir(dir); err != nil {
+		return "", err
+	} else if err = os.Chdir(dir); err != nil {
+		return "", err
+	} else if dir, err = os.Getwd(); err != nil {
+		return "", err
+	} else {
+		return dir, nil
+	}
+}
+
 func (e *Editor) suspend() error {
 	return suspend(e)
 }
@@ -354,3 +396,14 @@ func (e *Editor) Close() error {
 	e.wm.Close()
 	return e.ui.Close()
 }
+
+func expandHomedir(path string) (string, error) {
+	if !strings.HasPrefix(path, "~") {
+		return path, nil
+	}
+	homeDir, err := os.UserHomeDir()
+	if err != nil {
+		return "", err
+	}
+	return filepath.Join(homeDir, path[1:]), nil
+}

editor/editor_test.go

@@ -778,3 +778,33 @@ func TestEditorCmdlineQuitErr(t *testing.T) {
 		t.Errorf("err should be nil but got: %v", err)
 	}
 }
+
+func TestEditorChangeDirectory(t *testing.T) {
+	dir, err := os.Getwd()
+	if err != nil {
+		t.Errorf("err should be nil but got: %v", err)
+	}
+	ui := newTestUI()
+	editor := NewEditor(ui, window.NewManager(), cmdline.NewCmdline())
+	if err := editor.Init(); err != nil {
+		t.Errorf("err should be nil but got: %v", err)
+	}
+	if err := editor.OpenEmpty(); err != nil {
+		t.Errorf("err should be nil but got: %v", err)
+	}
+	go func() {
+		ui.Emit(event.Event{Type: event.PrintDirectory})
+		ui.Emit(event.Event{Type: event.ChangeDirectory, Arg: "../"})
+		ui.Emit(event.Event{Type: event.ChangeDirectory, Arg: "-"})
+		ui.Emit(event.Event{Type: event.Quit})
+	}()
+	if err := editor.Run(); err != nil {
+		t.Errorf("err should be nil but got: %v", err)
+	}
+	if err := editor.err; err == nil || err.Error() != dir {
+		t.Errorf("err should end with %q but got: %v", dir, err)
+	}
+	if err := editor.Close(); err != nil {
+		t.Errorf("err should be nil but got: %v", err)
+	}
+}

event/event.go

@@ -127,6 +127,9 @@ const (
 	MoveWindowBottom
 	MoveWindowLeft
 	MoveWindowRight
+
+	PrintDirectory
+	ChangeDirectory
 	Suspend
 	Quit
 	QuitAll