--multi to take optional argument to limit the number of selection

Close #1718
Related #688

src/constants.go

@@ -1,6 +1,7 @@
 package fzf
 
 import (
+	"math"
 	"os"
 	"time"
 
@@ -27,6 +28,7 @@ const (
 	spinnerDuration   = 200 * time.Millisecond
 	previewCancelWait = 500 * time.Millisecond
 	maxPatternLength  = 300
+	maxMulti          = math.MaxInt32
 
 	// Matcher
 	numPartitionsMultiplier = 8

src/options.go

@@ -38,7 +38,7 @@ const usage = `usage: fzf [options]
                           (default: length)
 
   Interface
-    -m, --multi           Enable multi-select with tab/shift-tab
+    -m, --multi[=MAX]     Enable multi-select with tab/shift-tab
     --no-mouse            Disable mouse
     --bind=KEYBINDS       Custom key bindings. Refer to the man page.
     --cycle               Enable cyclic scroll
@@ -162,7 +162,7 @@ type Options struct {
 	Sort        int
 	Tac         bool
 	Criteria    []criterion
-	Multi       bool
+	Multi       int
 	Ansi        bool
 	Mouse       bool
 	Theme       *tui.ColorTheme
@@ -215,7 +215,7 @@ func defaultOptions() *Options {
 		Sort:        1000,
 		Tac:         false,
 		Criteria:    []criterion{byScore, byLength},
-		Multi:       false,
+		Multi:       0,
 		Ansi:        false,
 		Mouse:       true,
 		Theme:       tui.EmptyTheme(),
@@ -314,13 +314,14 @@ func nextInt(args []string, i *int, message string) int {
 	return atoi(args[*i])
 }
 
-func optionalNumeric(args []string, i *int) int {
+func optionalNumeric(args []string, i *int, defaultValue int) int {
 	if len(args) > *i+1 {
 		if strings.IndexAny(args[*i+1], "0123456789") == 0 {
 			*i++
+			return atoi(args[*i])
 		}
 	}
-	return 1 // Don't care
+	return defaultValue
 }
 
 func splitNth(str string) []Range {
@@ -1033,7 +1034,7 @@ func parseOptions(opts *Options, allArgs []string) {
 		case "--with-nth":
 			opts.WithNth = splitNth(nextString(allArgs, &i, "nth expression required"))
 		case "-s", "--sort":
-			opts.Sort = optionalNumeric(allArgs, &i)
+			opts.Sort = optionalNumeric(allArgs, &i, 1)
 		case "+s", "--no-sort":
 			opts.Sort = 0
 		case "--tac":
@@ -1045,9 +1046,9 @@ func parseOptions(opts *Options, allArgs []string) {
 		case "+i":
 			opts.Case = CaseRespect
 		case "-m", "--multi":
-			opts.Multi = true
+			opts.Multi = optionalNumeric(allArgs, &i, maxMulti)
 		case "+m", "--no-multi":
-			opts.Multi = false
+			opts.Multi = 0
 		case "--ansi":
 			opts.Ansi = true
 		case "--no-ansi":
@@ -1190,6 +1191,8 @@ func parseOptions(opts *Options, allArgs []string) {
 				opts.WithNth = splitNth(value)
 			} else if match, _ := optString(arg, "-s", "--sort="); match {
 				opts.Sort = 1 // Don't care
+			} else if match, value := optString(arg, "-s", "--multi="); match {
+				opts.Multi = atoi(value)
 			} else if match, value := optString(arg, "--height="); match {
 				opts.Height = parseHeight(value)
 			} else if match, value := optString(arg, "--min-height="); match {

src/terminal.go

@@ -76,7 +76,7 @@ type Terminal struct {
 	xoffset    int
 	yanked     []rune
 	input      []rune
-	multi      bool
+	multi      int
 	sort       bool
 	toggleSort bool
 	delimiter  Delimiter
@@ -750,8 +750,12 @@ func (t *Terminal) printInfo() {
 			output += " -S"
 		}
 	}
-	if t.multi && len(t.selected) > 0 {
+	if len(t.selected) > 0 {
+		if t.multi == maxMulti {
 			output += fmt.Sprintf(" (%d)", len(t.selected))
+		} else {
+			output += fmt.Sprintf(" (%d/%d)", len(t.selected), t.multi)
+		}
 	}
 	if t.progress > 0 && t.progress < 100 {
 		output += fmt.Sprintf(" (%d%%)", t.progress)
@@ -1426,9 +1430,18 @@ func (t *Terminal) buildPlusList(template string, forcePlus bool) (bool, []*Item
 	return true, sels
 }
 
-func (t *Terminal) selectItem(item *Item) {
+func (t *Terminal) selectItem(item *Item) bool {
+	if len(t.selected) >= t.multi {
+		return false
+	}
+	if _, found := t.selected[item.Index()]; found {
+		return false
+	}
+
 	t.selected[item.Index()] = selectedItem{time.Now(), item}
 	t.version++
+
+	return true
 }
 
 func (t *Terminal) deselectItem(item *Item) {
@@ -1436,12 +1449,12 @@ func (t *Terminal) deselectItem(item *Item) {
 	t.version++
 }
 
-func (t *Terminal) toggleItem(item *Item) {
+func (t *Terminal) toggleItem(item *Item) bool {
 	if _, found := t.selected[item.Index()]; !found {
-		t.selectItem(item)
+		return t.selectItem(item)
-	} else {
-		t.deselectItem(item)
 	}
+	t.deselectItem(item)
+	return true
 }
 
 func (t *Terminal) killPreview(code int) {
@@ -1687,11 +1700,12 @@ func (t *Terminal) Loop() {
 				}
 			}
 		}
-		toggle := func() {
+		toggle := func() bool {
-			if t.cy < t.merger.Length() {
+			if t.cy < t.merger.Length() && t.toggleItem(t.merger.Get(t.cy).item) {
-				t.toggleItem(t.merger.Get(t.cy).item)
 				req(reqInfo)
+				return true
 			}
+			return false
 		}
 		scrollPreview := func(amount int) {
 			if !t.previewer.more {
@@ -1813,27 +1827,42 @@ func (t *Terminal) Loop() {
 					t.cx--
 				}
 			case actSelectAll:
-				if t.multi {
+				if t.multi > 0 {
 					for i := 0; i < t.merger.Length(); i++ {
-						t.selectItem(t.merger.Get(i).item)
+						if !t.selectItem(t.merger.Get(i).item) {
+							break
+						}
 					}
 					req(reqList, reqInfo)
 				}
 			case actDeselectAll:
-				if t.multi {
+				if t.multi > 0 {
 					t.selected = make(map[int32]selectedItem)
 					t.version++
 					req(reqList, reqInfo)
 				}
 			case actToggle:
-				if t.multi && t.merger.Length() > 0 {
+				if t.multi > 0 && t.merger.Length() > 0 && toggle() {
-					toggle()
 					req(reqList)
 				}
 			case actToggleAll:
-				if t.multi {
+				if t.multi > 0 {
+					prevIndexes := make(map[int]struct{})
+					for i := 0; i < t.merger.Length() && len(t.selected) > 0; i++ {
+						item := t.merger.Get(i).item
+						if _, found := t.selected[item.Index()]; found {
+							prevIndexes[i] = struct{}{}
+							t.deselectItem(item)
+						}
+					}
+
 					for i := 0; i < t.merger.Length(); i++ {
-						t.toggleItem(t.merger.Get(i).item)
+						if _, found := prevIndexes[i]; !found {
+							item := t.merger.Get(i).item
+							if !t.selectItem(item) {
+								break
+							}
+						}
 					}
 					req(reqList, reqInfo)
 				}
@@ -1848,14 +1877,12 @@ func (t *Terminal) Loop() {
 				}
 				return doAction(action{t: actToggleUp}, mapkey)
 			case actToggleDown:
-				if t.multi && t.merger.Length() > 0 {
+				if t.multi > 0 && t.merger.Length() > 0 && toggle() {
-					toggle()
 					t.vmove(-1, true)
 					req(reqList)
 				}
 			case actToggleUp:
-				if t.multi && t.merger.Length() > 0 {
+				if t.multi > 0 && t.merger.Length() > 0 && toggle() {
-					toggle()
 					t.vmove(1, true)
 					req(reqList)
 				}
@@ -1959,7 +1986,7 @@ func (t *Terminal) Loop() {
 				if me.S != 0 {
 					// Scroll
 					if t.window.Enclose(my, mx) && t.merger.Length() > 0 {
-						if t.multi && me.Mod {
+						if t.multi > 0 && me.Mod {
 							toggle()
 						}
 						t.vmove(me.S, true)
@@ -1999,7 +2026,7 @@ func (t *Terminal) Loop() {
 							t.cx = mx + t.xoffset
 						} else if my >= min {
 							// List
-							if t.vset(t.offset+my-min) && t.multi && me.Mod {
+							if t.vset(t.offset+my-min) && t.multi > 0 && me.Mod {
 								toggle()
 							}
 							req(reqList)

test/test_go.rb

@@ -371,6 +371,65 @@ class TestGoFZF < TestBase
     assert_equal %w[3 2 5 6 8 7], readonce.split($INPUT_RECORD_SEPARATOR)
   end
 
+  def test_multi_max
+    tmux.send_keys "seq 1 10 | #{FZF} -m 3 --bind A:select-all,T:toggle-all --preview 'echo [{+}]/{}'", :Enter
+
+    tmux.until { |lines| lines.item_count == 10 }
+
+    tmux.send_keys '1'
+    tmux.until do |lines|
+      lines[1].include?('[1]/1') && lines[-2].include?('2/10')
+    end
+
+    tmux.send_keys 'A'
+    tmux.until do |lines|
+      lines[1].include?('[1 10]/1') && lines[-2].include?('2/10 (2/3)')
+    end
+
+    tmux.send_keys :BSpace
+    tmux.until { |lines| lines[-2].include?('10/10 (2/3)') }
+
+    tmux.send_keys 'T'
+    tmux.until do |lines|
+      lines[1].include?('[2 3 4]/1') && lines[-2].include?('10/10 (3/3)')
+    end
+
+    %w[T A].each do |key|
+      tmux.send_keys key
+      tmux.until do |lines|
+        lines[1].include?('[1 5 6]/1') && lines[-2].include?('10/10 (3/3)')
+      end
+    end
+
+    tmux.send_keys :BTab
+    tmux.until do |lines|
+      lines[1].include?('[5 6]/2') && lines[-2].include?('10/10 (2/3)')
+    end
+
+    [:BTab, :BTab, 'A'].each do |key|
+      tmux.send_keys key
+      tmux.until do |lines|
+        lines[1].include?('[5 6 2]/3') && lines[-2].include?('10/10 (3/3)')
+      end
+    end
+
+    tmux.send_keys '2'
+    tmux.until { |lines| lines[-2].include?('1/10 (3/3)') }
+
+    tmux.send_keys 'T'
+    tmux.until do |lines|
+      lines[1].include?('[5 6]/2') && lines[-2].include?('1/10 (2/3)')
+    end
+
+    tmux.send_keys :BSpace
+    tmux.until { |lines| lines[-2].include?('10/10 (2/3)') }
+
+    tmux.send_keys 'A'
+    tmux.until do |lines|
+      lines[1].include?('[5 6 1]/1') && lines[-2].include?('10/10 (3/3)')
+    end
+  end
+
   def test_with_nth
     [true, false].each do |multi|
       tmux.send_keys "(echo '  1st 2nd 3rd/';