Implement metadata based previews in choose-files

docs/kittens/choose-files.rst

@@ -12,7 +12,7 @@ The choose-files kitten is designed to allow you to select files, very fast,
 with just a few key strokes. It operates like `fzf
 <https://github.com/junegunn/fzf/>`__ and similar fuzzy finders, except that
 it is specialised for finding files. As such it supports features such as
-filtering by file type, file type icons, content previews (coming soon) and
+filtering by file type, file type icons, content previews and
 so on, out of the box. It can be used as a drop in (but much more efficient and
 keyboard friendly) replacement for the :guilabel:`File open and save`
 dialog boxes common to GUI programs. On Linux, with the help of the

kittens/choose_files/main.go

@@ -97,8 +97,8 @@ func (m Mode) WindowTitle() string {
 }
 
 type render_state struct {
-	num_matches, num_of_slots, num_before, num_per_column, num_columns, num_shown int
+	num_matches, num_of_slots, num_before, num_per_column, num_columns, num_shown, preview_width int
-	first_idx                                                                     CollectionIndex
+	first_idx                                                                                    CollectionIndex
 }
 
 type State struct {
@@ -116,6 +116,7 @@ type State struct {
 	filter_map               map[string]Filter
 	filter_names             []string
 	show_hidden              bool
+	show_preview             bool
 	respect_ignores          bool
 	sort_by_last_modified    bool
 	global_ignores           ignorefiles.IgnoreFile
@@ -131,6 +132,7 @@ type State struct {
 
 func (s State) DisplayTitle() bool                    { return s.display_title }
 func (s State) ShowHidden() bool                      { return s.show_hidden }
+func (s State) ShowPreview() bool                     { return s.show_preview }
 func (s State) RespectIgnores() bool                  { return s.respect_ignores }
 func (s State) SortByLastModified() bool              { return s.sort_by_last_modified }
 func (s State) GlobalIgnores() ignorefiles.IgnoreFile { return s.global_ignores }
@@ -209,6 +211,7 @@ type Handler struct {
 	shortcut_tracker config.ShortcutTracker
 	msg_printer      *message.Printer
 	spinner          *tui.Spinner
+	preview_manager  *PreviewManager
 }
 
 func (h *Handler) draw_screen() (err error) {
@@ -482,6 +485,9 @@ func (h *Handler) dispatch_action(name, args string) (err error) {
 		}
 	case "toggle":
 		switch args {
+		case "preview":
+			h.state.show_preview = !h.state.show_preview
+			return h.draw_screen()
 		case "dotfiles":
 			h.state.show_hidden = !h.state.show_hidden
 			h.result_manager.set_show_hidden()
@@ -577,6 +583,7 @@ func (h *Handler) OnText(text string, from_key_event, in_bracketed_paste bool) (
 
 type CachedValues struct {
 	Show_hidden           bool `json:"show_hidden"`
+	Hide_preview          bool `json:"hide_preview"`
 	Respect_ignores       bool `json:"respect_ignores"`
 	Sort_by_last_modified bool `json:"sort_by_last_modified"`
 }
@@ -593,7 +600,7 @@ var cached_values = sync.OnceValue(func() *CachedValues {
 })
 
 func (s State) save_cached_values() {
-	c := CachedValues{Show_hidden: s.show_hidden, Respect_ignores: s.respect_ignores, Sort_by_last_modified: s.sort_by_last_modified}
+	c := CachedValues{Show_hidden: s.show_hidden, Respect_ignores: s.respect_ignores, Sort_by_last_modified: s.sort_by_last_modified, Hide_preview: !s.show_preview}
 	fname := filepath.Join(utils.CacheDir(), cache_filename)
 	if data, err := json.Marshal(c); err == nil {
 		_ = os.WriteFile(fname, data, 0600)
@@ -661,6 +668,8 @@ func (h *Handler) set_state_from_config(conf *Config, opts *Options) (err error)
 	h.state.sort_by_last_modified = false
 	h.state.respect_ignores = true
 	h.state.show_hidden = false
+	h.state.show_preview = true
+
 	switch conf.Show_hidden {
 	case Show_hidden_true, Show_hidden_y, Show_hidden_yes:
 		h.state.show_hidden = true
@@ -685,6 +694,15 @@ func (h *Handler) set_state_from_config(conf *Config, opts *Options) (err error)
 	case Sort_by_last_modified_last:
 		h.state.sort_by_last_modified = cached_values().Sort_by_last_modified
 	}
+	switch conf.Show_preview {
+	case Show_preview_true, Show_preview_y, Show_preview_yes:
+		h.state.show_preview = true
+	case Show_preview_false, Show_preview_n, Show_preview_no:
+		h.state.show_preview = false
+	case Show_preview_last:
+		h.state.show_preview = !cached_values().Hide_preview
+	}
+
 	h.state.global_ignores = ignorefiles.NewGitignore()
 	if err = h.state.global_ignores.LoadLines(conf.Ignore...); err != nil {
 		return err
@@ -753,6 +771,7 @@ func main(_ *cli.Command, opts *Options, args []string) (rc int, err error) {
 		return 1, err
 	}
 	handler.result_manager = NewResultManager(handler.err_chan, &handler.state, lp.WakeupMainThread)
+	handler.preview_manager = NewPreviewManager(handler.err_chan, &handler.state, lp.WakeupMainThread)
 	switch len(args) {
 	case 0:
 		if default_cwd, err = os.Getwd(); err != nil {

kittens/choose_files/main.py

@@ -40,6 +40,10 @@ Anchored patterns match with respect to whatever directory is currently being di
 Can be specified multiple times to use multiple patterns. Note that every pattern
 has to be checked against every file, so use sparingly.
 ''')
+
+opt('show_preview', 'last', choices=('last', 'yes', 'y', 'true', 'no', 'n', 'false'), long_text='''
+Whether to show a preview of the current file/directory. The default value of :code:`last` means remember the last
+used value. This setting can be toggled withing the program.''')
 egr()  # }}}
 
 agr('shortcuts', 'Keyboard shortcuts')  # {{{
@@ -81,6 +85,7 @@ map('Previous filter', 'prev_filter alt+f -1')
 map('Toggle showing dotfiles', 'toggle_dotfiles alt+h toggle dotfiles')
 map('Toggle showing ignored files', 'toggle_ignorefiles alt+i toggle ignorefiles')
 map('Toggle sorting by dates', 'toggle_sort_by_dates alt+d toggle sort_by_dates')
+map('Toggle showing preview', 'toggle_preview alt+p toggle preview')
 
 egr()  # }}}
 

kittens/choose_files/preview.go

@@ -0,0 +1,201 @@
+package choose_files
+
+import (
+	"fmt"
+	"io/fs"
+	"os"
+	"path/filepath"
+	"slices"
+	"strings"
+	"sync"
+
+	"github.com/kovidgoyal/kitty/tools/icons"
+	"github.com/kovidgoyal/kitty/tools/utils"
+	"github.com/kovidgoyal/kitty/tools/utils/humanize"
+	"github.com/kovidgoyal/kitty/tools/utils/style"
+	"github.com/kovidgoyal/kitty/tools/wcswidth"
+)
+
+var _ = fmt.Print
+
+type Preview interface {
+	Render(h *Handler, x, y, width, height int)
+}
+
+type PreviewManager struct {
+	report_errors    chan error
+	settings         Settings
+	WakeupMainThread func() bool
+	cache            map[string]Preview
+	lock             sync.Mutex
+}
+
+func NewPreviewManager(err_chan chan error, settings Settings, WakeupMainThread func() bool) *PreviewManager {
+	return &PreviewManager{
+		report_errors: err_chan, settings: settings, WakeupMainThread: WakeupMainThread,
+		cache: make(map[string]Preview),
+	}
+}
+
+func (pm *PreviewManager) cached_preview(path string) Preview {
+	pm.lock.Lock()
+	defer pm.lock.Unlock()
+	return pm.cache[path]
+}
+
+func (pm *PreviewManager) set_cached_preview(path string, val Preview) {
+	pm.lock.Lock()
+	defer pm.lock.Unlock()
+	pm.cache[path] = val
+}
+
+func (h *Handler) render_wrapped_text_in_region(text string, x, y, width, height int, centered bool) int {
+	lines := style.WrapTextAsLines(text, width, style.WrapOptions{})
+	for i, line := range lines {
+		extra := 0
+		if centered {
+			extra = max(0, width-wcswidth.Stringwidth(line)) / 2
+		}
+		h.lp.MoveCursorTo(x+extra, y+i)
+		h.lp.QueueWriteString(line)
+		if i >= height {
+			break
+		}
+	}
+	return len(lines)
+}
+
+type MessagePreview struct {
+	title    string
+	msg      string
+	trailers []string
+}
+
+func (p MessagePreview) Render(h *Handler, x, y, width, height int) {
+	offset := 0
+	if p.title != "" {
+		offset += h.render_wrapped_text_in_region(p.title, x, y, width, height, true)
+	}
+	offset += h.render_wrapped_text_in_region(p.msg, x, y+offset, width, height-offset, false)
+	limit := height - offset
+	if limit > 1 {
+		for i, line := range p.trailers {
+			text := wcswidth.TruncateToVisualLength(line, width-1)
+			if len(text) < len(line) {
+				text += "…"
+			}
+			h.lp.MoveCursorTo(x, y+offset+i-1)
+			if i >= limit {
+				h.lp.QueueWriteString("…")
+				break
+			}
+			h.lp.QueueWriteString(text)
+		}
+	}
+}
+
+func NewErrorPreview(err error) Preview {
+	sctx := style.Context{AllowEscapeCodes: true}
+	text := fmt.Sprintf("%s: %s", sctx.SprintFunc("fg=red")("Error"), err)
+	return &MessagePreview{msg: text}
+}
+
+func write_file_metadata(abspath string, metadata fs.FileInfo, entries []fs.DirEntry) (header string, trailers []string) {
+	buf := strings.Builder{}
+	buf.Grow(4096)
+	add := func(key, val string) { fmt.Fprintf(&buf, "%s: %s\n", key, val) }
+	ftype := metadata.Mode().Type()
+	const file_icon = " "
+	switch ftype {
+	case 0:
+		add("Size", humanize.Bytes(uint64(metadata.Size())))
+	case fs.ModeSymlink:
+		if tgt, err := os.Readlink(abspath); err == nil {
+			add("Target", tgt)
+		} else {
+			add("Target", err.Error())
+		}
+	case fs.ModeDir:
+		num_files, num_dirs := 0, 0
+		for _, e := range entries {
+			if e.IsDir() {
+				num_dirs++
+			} else {
+				num_files++
+			}
+		}
+		add("Children", fmt.Sprintf("%d %s  %d %s", num_dirs, icons.IconForFileWithMode("dir", fs.ModeDir, false), num_files, file_icon))
+	}
+	add("Modified", humanize.Time(metadata.ModTime()))
+	add("Mode", metadata.Mode().String())
+	if len(entries) > 0 {
+		type entry struct {
+			lname string
+			ftype fs.FileMode
+		}
+		type_map := make(map[string]entry, len(entries))
+		for _, e := range entries {
+			type_map[e.Name()] = entry{strings.ToLower(e.Name()), e.Type()}
+		}
+		names := utils.Map(func(e fs.DirEntry) string { return e.Name() }, entries)
+		slices.SortFunc(names, func(a, b string) int { return strings.Compare(type_map[a].lname, type_map[b].lname) })
+		fmt.Fprintln(&buf, "Contents:")
+		for _, n := range names {
+			trailers = append(trailers, icons.IconForFileWithMode(n, type_map[n].ftype, false)+"  "+n)
+		}
+	}
+	return buf.String(), trailers
+}
+
+func NewDirectoryPreview(abspath string, metadata fs.FileInfo) Preview {
+	entries, err := os.ReadDir(abspath)
+	if err != nil {
+		return NewErrorPreview(fmt.Errorf("failed to read the directory %s with error: %w", abspath, err))
+	}
+	title := icons.IconForFileWithMode("dir", fs.ModeDir, false) + "  Directory\n"
+	header, extra := write_file_metadata(abspath, metadata, entries)
+	return &MessagePreview{title: title, msg: header, trailers: extra}
+}
+
+func NewFileMetadataPreview(abspath string, metadata fs.FileInfo) Preview {
+	title := icons.IconForFileWithMode(filepath.Base(abspath), metadata.Mode().Type(), false) + "  File"
+	h, t := write_file_metadata(abspath, metadata, nil)
+	return &MessagePreview{title: title, msg: h, trailers: t}
+}
+
+func (pm *PreviewManager) preview_for(abspath string, ftype fs.FileMode) (ans Preview) {
+	if ans = pm.cached_preview(abspath); ans != nil {
+		return ans
+	}
+	defer func() { pm.set_cached_preview(abspath, ans) }()
+	s, err := os.Lstat(abspath)
+	if err != nil {
+		return NewErrorPreview(err)
+	}
+	if s.IsDir() {
+		return NewDirectoryPreview(abspath, s)
+	}
+	if ftype&fs.ModeSymlink != 0 && ftype&SymlinkToDir != 0 {
+		s, err = os.Stat(abspath)
+		if err != nil {
+			return NewErrorPreview(err)
+		}
+		return NewDirectoryPreview(abspath, s)
+	}
+	return NewFileMetadataPreview(abspath, s)
+}
+
+func (h *Handler) draw_preview_content(x, y, width, height int) {
+	matches, _ := h.get_results()
+	r := matches.At(h.state.CurrentIndex())
+	if r == nil {
+		h.render_wrapped_text_in_region("No preview available", x, y, width, height, false)
+		return
+	}
+	abspath := filepath.Join(h.state.CurrentDir(), r.text)
+	if p := h.preview_manager.preview_for(abspath, r.ftype); p == nil {
+		h.render_wrapped_text_in_region("No preview available", x, y, width, height, false)
+	} else {
+		p.Render(h, x, y, width, height)
+	}
+}

kittens/choose_files/results.go

@@ -208,8 +208,22 @@ func (h *Handler) draw_column_of_matches(matches ResultsType, current_idx int, x
 	}
 }
 
-func (h *Handler) draw_list_of_results(matches *SortedResults, y, height int) (num_cols, num_shown int) {
+func (h *Handler) draw_list_of_results(matches *SortedResults, y, height int) (num_cols, num_shown, preview_width int) {
+	const BASE_COL_WIDTH = 40
 	available_width := h.screen_size.width - 2
+	show_preview := h.state.ShowPreview()
+	if show_preview && available_width < BASE_COL_WIDTH+30 {
+		show_preview = false
+	}
+	if show_preview {
+		switch {
+		case available_width < BASE_COL_WIDTH*2:
+			preview_width = max(30, available_width/2)
+		default:
+			preview_width = BASE_COL_WIDTH
+		}
+		available_width -= preview_width
+	}
 	col_width := available_width
 	num_cols = 1
 	calc_num_cols := func(num_matches int) int {
@@ -217,7 +231,7 @@ func (h *Handler) draw_list_of_results(matches *SortedResults, y, height int) (n
 			return 0
 		}
 		if num_matches > height {
-			col_width = 40
+			col_width = BASE_COL_WIDTH
 			num_cols = available_width / col_width
 			for num_cols > 0 && height*(num_cols-1) >= num_matches {
 				num_cols--
@@ -239,7 +253,7 @@ func (h *Handler) draw_list_of_results(matches *SortedResults, y, height int) (n
 		num_shown += len(col)
 		x += col_width
 	}
-	return len(columns), num_shown
+	return len(columns), num_shown, preview_width
 }
 
 func (h *Handler) draw_num_of_matches(num_shown, y int, in_progress bool) {
@@ -274,6 +288,23 @@ func (h *Handler) draw_num_of_matches(num_shown, y int, in_progress bool) {
 	}
 }
 
+func (h *Handler) draw_preview(y int) {
+	x := h.screen_size.width - h.state.last_render.preview_width
+	height := h.state.last_render.num_of_slots
+	buf := strings.Builder{}
+	buf.Grow(16 * height)
+	buf.WriteString(fmt.Sprintf(loop.MoveCursorToTemplate, y-1, x))
+	buf.WriteString("┬")
+	for i := range height {
+		buf.WriteString(fmt.Sprintf(loop.MoveCursorToTemplate, y+i, x))
+		buf.WriteString("│")
+	}
+	buf.WriteString(fmt.Sprintf(loop.MoveCursorToTemplate, y+height, x))
+	buf.WriteString("┴")
+	h.lp.QueueWriteString(buf.String())
+	h.draw_preview_content(x+1, y, h.state.last_render.preview_width-1, h.state.last_render.num_of_slots)
+}
+
 func (h *Handler) draw_results(y, bottom_margin int, matches *SortedResults, in_progress bool) (height int) {
 	height = h.screen_size.height - y - bottom_margin
 	h.lp.MoveCursorTo(1, 1+y)
@@ -286,15 +317,19 @@ func (h *Handler) draw_results(y, bottom_margin int, matches *SortedResults, in_
 	num_cols := 0
 	num := matches.Len()
 	num_shown := 0
+	h.state.last_render.preview_width = 0
 	switch num {
 	case 0:
 		h.draw_no_matches_message(in_progress)
 	default:
-		num_cols, num_shown = h.draw_list_of_results(matches, y, h.state.last_render.num_of_slots)
+		num_cols, num_shown, h.state.last_render.preview_width = h.draw_list_of_results(matches, y, h.state.last_render.num_of_slots)
 	}
 	h.state.last_render.num_matches = num
 	h.state.last_render.num_shown = num_shown
 	h.draw_num_of_matches(h.state.last_render.num_of_slots*num_cols, y+height-2, in_progress)
+	if h.state.last_render.preview_width > 0 {
+		h.draw_preview(y)
+	}
 	return
 }
 

kittens/choose_files/search-bar.go

@@ -80,6 +80,9 @@ func (h *Handler) draw_controls(y int) (max_width int) {
 		h.state.respect_ignores = !h.state.respect_ignores
 		h.result_manager.set_respect_ignores()
 	})
+	add_control(" ", utils.IfElse(h.state.ShowPreview(), "hide preview", "show preview"), func() {
+		h.state.show_preview = !h.state.show_preview
+	})
 	add_control(utils.IfElse(h.state.SortByLastModified(), " ", " "), utils.IfElse(h.state.SortByLastModified(), "sort names", "sort dates"), func() {
 		h.state.sort_by_last_modified = !h.state.sort_by_last_modified
 		h.result_manager.set_sort_by_last_modified()

kitty_tests/completion.py

@@ -85,6 +85,7 @@ def completion(self: TestCompletion, tdir: str):
         env['PATH'] = os.path.join(tdir, 'bin')
         env['HOME'] = os.path.join(tdir, 'sub')
         env['KITTY_CONFIG_DIRECTORY'] = os.path.join(tdir, 'sub')
+        print(1111111, all_argv)
         cp = subprocess.run(
             [kitten(), '__complete__', 'json'],
             check=True, stdout=subprocess.PIPE, cwd=tdir, input=json.dumps(all_argv).encode(), env=env