Refactor Nav API around symlinks handling (mostly) (#33)

* gofmt ui.go

* Refactor Nav API around symlinks handling (mostly)

1. Get both `Lstat` and `Stat` while reading the files. Stat info is
   used by default, but we still can tell it's a link if needed.
2. Remove all other `Stat` calls from different places.
3. Handle hidden files while reading.
4. `currFile` now returns error if there are no files.
5. `currEmpty` and `currPath` not longer necessary, removed.
6. `open` now returns a named error ErrNotDir, where expected.

7. Side effect: Links that point at directories are now sorted among
   "actual" directories.

app.go

@@ -76,11 +76,9 @@ func (app *App) handleInp() {
 }
 
 func (app *App) exportVars() {
-	dir := app.nav.currDir()
-
 	var envFile string
-	if len(dir.fi) != 0 {
+	if f, err := app.nav.currFile(); err == nil {
-		envFile = app.nav.currPath()
+		envFile = f.Path
 	}
 
 	marks := app.nav.currMarks()

eval.go

@@ -178,31 +178,16 @@ func (e *CallExpr) eval(app *App, args []string) {
 		}
 		app.ui.loadFile(app.nav)
 	case "open":
-		dir := app.nav.currDir()
+		err := app.nav.open()
-
+		if err == nil {
-		if len(dir.fi) == 0 {
+			app.ui.loadFile(app.nav)
 			return
 		}
-
+		if err != ErrNotDir {
-		path := app.nav.currPath()
-
-		f, err := os.Stat(path)
-		if err != nil {
-			msg := fmt.Sprintf("open: %s", err)
-			app.ui.message = msg
-			log.Print(msg)
-			return
-		}
-
-		if f.IsDir() {
-			if err := app.nav.open(); err != nil {
 			app.ui.message = err.Error()
 			log.Print(err)
 			return
 		}
-			app.ui.loadFile(app.nav)
-			return
-		}
 
 		if gSelectionPath != "" {
 			out, err := os.Create(gSelectionPath)
@@ -211,9 +196,14 @@ func (e *CallExpr) eval(app *App, args []string) {
 			}
 			defer out.Close()
 
+			var path string
 			if len(app.nav.marks) != 0 {
 				marks := app.nav.currMarks()
 				path = strings.Join(marks, "\n")
+			} else if curr, err := app.nav.currFile(); err == nil {
+				path = curr.Path
+			} else {
+				return
 			}
 
 			_, err = out.WriteString(path)

nav.go

@@ -3,7 +3,6 @@ package main
 import (
 	"errors"
 	"fmt"
-	"io/ioutil"
 	"log"
 	"os"
 	"os/exec"
@@ -12,14 +11,21 @@ import (
 	"strings"
 )
 
-type Dir struct {
+type LinkState int8
-	ind  int // which entry is highlighted
+
-	pos  int // which line in the ui highlighted entry is
+const (
-	path string
+	NotLink LinkState = iota
-	fi   []os.FileInfo
+	Working
+	Broken
+)
+
+type File struct {
+	os.FileInfo
+	LinkState LinkState
+	Path      string
 }
 
-type ByName []os.FileInfo
+type ByName []*File
 
 func (a ByName) Len() int      { return len(a) }
 func (a ByName) Swap(i, j int) { a[i], a[j] = a[j], a[i] }
@@ -28,19 +34,19 @@ func (a ByName) Less(i, j int) bool {
 	return strings.ToLower(a[i].Name()) < strings.ToLower(a[j].Name())
 }
 
-type BySize []os.FileInfo
+type BySize []*File
 
 func (a BySize) Len() int           { return len(a) }
 func (a BySize) Swap(i, j int)      { a[i], a[j] = a[j], a[i] }
 func (a BySize) Less(i, j int) bool { return a[i].Size() < a[j].Size() }
 
-type ByTime []os.FileInfo
+type ByTime []*File
 
 func (a ByTime) Len() int           { return len(a) }
 func (a ByTime) Swap(i, j int)      { a[i], a[j] = a[j], a[i] }
 func (a ByTime) Less(i, j int) bool { return a[i].ModTime().Before(a[j].ModTime()) }
 
-type ByDir []os.FileInfo
+type ByDir []*File
 
 func (a ByDir) Len() int      { return len(a) }
 func (a ByDir) Swap(i, j int) { a[i], a[j] = a[j], a[i] }
@@ -52,7 +58,7 @@ func (a ByDir) Less(i, j int) bool {
 	return a[i].IsDir()
 }
 
-type ByNum []os.FileInfo
+type ByNum []*File
 
 func (a ByNum) Len() int      { return len(a) }
 func (a ByNum) Swap(i, j int) { a[i], a[j] = a[j], a[i] }
@@ -85,15 +91,10 @@ func (a ByNum) Less(i, j int) bool {
 	return i < j
 }
 
-func organizeFiles(fi []os.FileInfo) []os.FileInfo {
+func getFilesSorted(path string) []*File {
-	if !gOpts.hidden {
+	fi, err := readdir(path)
-		var tmp []os.FileInfo
+	if err != nil {
-		for _, f := range fi {
+		log.Printf("reading directory: %s", err)
-			if f.Name()[0] != '.' {
-				tmp = append(tmp, f)
-			}
-		}
-		fi = tmp
 	}
 
 	switch gOpts.sortby {
@@ -116,34 +117,72 @@ func organizeFiles(fi []os.FileInfo) []os.FileInfo {
 	return fi
 }
 
-func newDir(path string) *Dir {
+func readdir(path string) ([]*File, error) {
-	fi, err := ioutil.ReadDir(path)
+	f, err := os.Open(path)
 	if err != nil {
-		log.Printf("reading directory: %s", err)
+		return nil, err
 	}
 
-	fi = organizeFiles(fi)
+	names, err := f.Readdirnames(-1)
+	fi := make([]*File, 0, len(names))
+	for _, filename := range names {
+		if !gOpts.hidden && filename[0] == '.' {
+			continue
+		}
 
+		fpath := filepath.Join(path, filename)
+
+		lstat, lerr := os.Lstat(fpath)
+		if os.IsNotExist(lerr) {
+			continue
+		}
+		if lerr != nil {
+			return fi, lerr
+		}
+
+		var linkState LinkState
+
+		if lstat.Mode()&os.ModeSymlink != 0 {
+			stat, serr := os.Stat(fpath)
+			if serr == nil {
+				linkState = Working
+				lstat = stat
+			} else {
+				linkState = Broken
+				log.Printf("getting link destination info: %s", serr)
+			}
+		}
+
+		fi = append(fi, &File{
+			FileInfo:  lstat,
+			LinkState: linkState,
+			Path:      fpath,
+		})
+	}
+	return fi, err
+}
+
+type Dir struct {
+	ind  int // which entry is highlighted
+	pos  int // which line in the ui highlighted entry is
+	path string
+	fi   []*File
+}
+
+func newDir(path string) *Dir {
 	return &Dir{
 		path: path,
-		fi:   fi,
+		fi:   getFilesSorted(path),
 	}
 }
 
 func (dir *Dir) renew(height int) {
-	fi, err := ioutil.ReadDir(dir.path)
-	if err != nil {
-		log.Printf("reading directory: %s", err)
-	}
-
-	fi = organizeFiles(fi)
-
 	var name string
 	if len(dir.fi) != 0 {
 		name = dir.fi[dir.ind].Name()
 	}
 
-	dir.fi = fi
+	dir.fi = getFilesSorted(dir.path)
 
 	dir.load(dir.ind, dir.pos, height, name)
 }
@@ -296,8 +335,17 @@ func (nav *Nav) updir() error {
 	return nil
 }
 
+var ErrNotDir = fmt.Errorf("not a directory")
+
 func (nav *Nav) open() error {
-	path := nav.currPath()
+	curr, err := nav.currFile()
+	if err != nil {
+		return err
+	}
+	if !curr.IsDir() {
+		return ErrNotDir
+	}
+	path := curr.Path
 
 	dir := newDir(path)
 
@@ -354,11 +402,12 @@ func (nav *Nav) toggleMark(path string) {
 }
 
 func (nav *Nav) toggle() {
-	if nav.currEmpty() {
+	curr, err := nav.currFile()
+	if err != nil {
 		return
 	}
 
-	nav.toggleMark(nav.currPath())
+	nav.toggleMark(curr.Path)
 
 	nav.down(1)
 }
@@ -373,13 +422,12 @@ func (nav *Nav) invert() {
 
 func (nav *Nav) save(keep bool) error {
 	if len(nav.marks) == 0 {
-		if nav.currEmpty() {
+		curr, err := nav.currFile()
+		if err != nil {
 			return errors.New("no file selected")
 		}
 
-		path := nav.currPath()
+		if err := saveFiles([]string{curr.Path}, keep); err != nil {
-
-		if err := saveFiles([]string{path}, keep); err != nil {
 			return err
 		}
 	} else {
@@ -433,23 +481,17 @@ func (nav *Nav) paste() error {
 	return nil
 }
 
-func (nav *Nav) currEmpty() bool {
-	return len(nav.dirs[len(nav.dirs)-1].fi) == 0
-}
-
 func (nav *Nav) currDir() *Dir {
 	return nav.dirs[len(nav.dirs)-1]
 }
 
-func (nav *Nav) currFile() os.FileInfo {
+func (nav *Nav) currFile() (*File, error) {
 	last := nav.dirs[len(nav.dirs)-1]
-	return last.fi[last.ind]
-}
 
-func (nav *Nav) currPath() string {
+	if len(last.fi) == 0 {
-	last := nav.dirs[len(nav.dirs)-1]
+		return nil, fmt.Errorf("empty directory")
-	curr := last.fi[last.ind]
+	}
-	return filepath.Join(last.path, curr.Name())
+	return last.fi[last.ind], nil
 }
 
 func (nav *Nav) currMarks() []string {

ui.go

@@ -236,6 +236,15 @@ func (win *Win) printd(dir *Dir, marks map[string]bool) {
 
 	for i, f := range dir.fi[beg:end] {
 		switch {
+		case f.LinkState != NotLink:
+			if f.LinkState == Working {
+				fg = termbox.ColorCyan
+				if f.Mode().IsDir() {
+					fg |= termbox.AttrBold
+				}
+			} else {
+				fg = termbox.ColorMagenta
+			}
 		case f.Mode().IsRegular():
 			if f.Mode()&0111 != 0 {
 				fg = termbox.AttrBold | termbox.ColorGreen
@@ -244,8 +253,6 @@ func (win *Win) printd(dir *Dir, marks map[string]bool) {
 			}
 		case f.Mode().IsDir():
 			fg = termbox.AttrBold | termbox.ColorBlue
-		case f.Mode()&os.ModeSymlink != 0:
-			fg = termbox.ColorCyan
 		case f.Mode()&os.ModeNamedPipe != 0:
 			fg = termbox.ColorRed
 		case f.Mode()&os.ModeSocket != 0:
@@ -390,39 +397,26 @@ func (ui *UI) renew() {
 }
 
 func (ui *UI) loadFile(nav *Nav) {
-	dir := nav.currDir()
+	curr, err := nav.currFile()
-
+	if err != nil {
-	if len(dir.fi) == 0 {
 		return
 	}
 
-	curr := nav.currFile()
-
 	ui.message = fmt.Sprintf("%v %v %v", curr.Mode(), humanize(curr.Size()), curr.ModTime().Format(time.ANSIC))
 
 	if !gOpts.preview {
 		return
 	}
 
-	path := nav.currPath()
+	if curr.IsDir() {
-
+		dir := newDir(curr.Path)
-	f, err := os.Stat(path)
+		dir.load(nav.inds[curr.Path], nav.poss[curr.Path], nav.height, nav.names[curr.Path])
-	if err != nil {
-		msg := fmt.Sprintf("getting file information: %s", err)
-		ui.message = msg
-		log.Print(msg)
-		return
-	}
-
-	if f.IsDir() {
-		dir := newDir(path)
-		dir.load(nav.inds[path], nav.poss[path], nav.height, nav.names[path])
 		ui.dirprev = dir
-	} else if f.Mode().IsRegular() {
+	} else if curr.Mode().IsRegular() {
 		var reader io.Reader
 
 		if len(gOpts.previewer) != 0 {
-			cmd := exec.Command(gOpts.previewer, path, strconv.Itoa(nav.height))
+			cmd := exec.Command(gOpts.previewer, curr.Path, strconv.Itoa(nav.height))
 
 			out, err := cmd.StdoutPipe()
 			if err != nil {
@@ -441,7 +435,7 @@ func (ui *UI) loadFile(nav *Nav) {
 			defer out.Close()
 			reader = out
 		} else {
-			f, err := os.Open(path)
+			f, err := os.Open(curr.Path)
 			if err != nil {
 				msg := fmt.Sprintf("opening file: %s", err)
 				ui.message = msg
@@ -489,7 +483,7 @@ func (ui *UI) draw(nav *Nav) {
 	// leave the cursor at the beginning of the current file for screen readers
 	var length, woff, doff int
 	defer func() {
-		fmt.Printf("[%d;%dH", ui.wins[woff+length-1].y + nav.dirs[doff+length-1].pos + 1, ui.wins[woff+length-1].x + 1)
+		fmt.Printf("[%d;%dH", ui.wins[woff+length-1].y+nav.dirs[doff+length-1].pos+1, ui.wins[woff+length-1].x+1)
 	}()
 
 	defer termbox.Flush()
@@ -519,20 +513,12 @@ func (ui *UI) draw(nav *Nav) {
 	defer ui.msgwin.print(0, 0, fg, bg, ui.message)
 
 	if gOpts.preview {
-		if len(dir.fi) == 0 {
+		f, err := nav.currFile()
+		if err != nil {
 			return
 		}
 
 		preview := ui.wins[len(ui.wins)-1]
-		path := nav.currPath()
-
-		f, err := os.Stat(path)
-		if err != nil {
-			msg := fmt.Sprintf("getting file information: %s", err)
-			ui.message = msg
-			log.Print(msg)
-			return
-		}
 
 		if f.IsDir() {
 			preview.printd(ui.dirprev, nav.marks)