Add field-based tracking across reloads (--track=NTH)

Allow --track to accept an optional nth expression for cross-reload tracking. When a reload is triggered, fzf extracts a tracking key from the current item using the nth expression, blocks the UI, and searches for a matching item in the reloaded list. - --track=.. tracks by entire line, --track=1 by first field, etc. - --track without NTH retains existing index-based behavior - UI is blocked during search (dimmed query, hidden cursor, +T*/+t*) - reload unblocks eagerly on match; reload-sync waits for stream end - Escape/Ctrl-C cancels blocked state without quitting - track-current action accepts optional nth: track-current(1) - Validate nth expression at parse time for both --track and track() - Cache trackKeyFor results per item to avoid redundant computation - Rename executeRegexp to argActionRegexp Close #4701 Close #3460
2026-08-05 07:28:37 +08:00 · 2026-03-14 20:52:04 +09:00
parent 7a811f0cb8
commit 9f422851fe
5 changed files with 370 additions and 17 deletions
@@ -594,6 +594,7 @@ type Options struct {
 	Sort              int
 	Raw               bool
 	Track             trackOption
+	TrackNth          []Range
 	Tac               bool
 	Tail              int
 	Criteria          []criterion
@@ -1610,7 +1611,7 @@ func parseWalkerOpts(str string) (walkerOpts, error) {
 }

 var (
-	executeRegexp    *regexp.Regexp
+	argActionRegexp  *regexp.Regexp
 	splitRegexp      *regexp.Regexp
 	actionNameRegexp *regexp.Regexp
 )
@@ -1629,8 +1630,8 @@ const (
 )

 func init() {
-	executeRegexp = regexp.MustCompile(
-		`(?si)[:+](become|execute(?:-multi|-silent)?|reload(?:-sync)?|preview|(?:change|bg-transform|transform)-(?:query|prompt|(?:border|list|preview|input|header|footer)-label|header-lines|header|footer|search|with-nth|nth|pointer|ghost)|bg-transform|transform|change-(?:preview-window|preview|multi)|(?:re|un|toggle-)bind|pos|put|print|search|trigger)`)
+	argActionRegexp = regexp.MustCompile(
+		`(?si)[:+](become|execute(?:-multi|-silent)?|reload(?:-sync)?|preview|(?:change|bg-transform|transform)-(?:query|prompt|(?:border|list|preview|input|header|footer)-label|header-lines|header|footer|search|with-nth|nth|pointer|ghost)|bg-transform|transform|change-(?:preview-window|preview|multi)|(?:re|un|toggle-)bind|pos|put|print|search|trigger|track(?:-current)?)`)
 	splitRegexp = regexp.MustCompile("[,:]+")
 	actionNameRegexp = regexp.MustCompile("(?i)^[a-z-]+")
 }
@@ -1639,7 +1640,7 @@ func maskActionContents(action string) string {
 	masked := ""
 Loop:
 	for len(action) > 0 {
-		loc := executeRegexp.FindStringIndex(action)
+		loc := argActionRegexp.FindStringIndex(action)
 		if loc == nil {
 			masked += action
 			break
@@ -1694,7 +1695,7 @@ Loop:
 }

 func parseSingleActionList(str string) ([]*action, error) {
-	// We prepend a colon to satisfy executeRegexp and remove it later
+	// We prepend a colon to satisfy argActionRegexp and remove it later
 	masked := maskActionContents(":" + str)[1:]
 	return parseActionList(masked, str, []*action{}, false)
 }
@@ -1954,6 +1955,12 @@ func parseActionList(masked string, original string, prevActions []*action, putA
 					if _, _, err := parseKeyChords(actionArg, spec[0:offset]+" target required"); err != nil {
 						return nil, err
 					}
+				case actTrackCurrent:
+					if len(actionArg) > 0 {
+						if _, err := splitNth(actionArg); err != nil {
+							return nil, err
+						}
+					}
 				case actChangePreviewWindow:
 					opts := previewOpts{}
 					for _, arg := range strings.Split(actionArg, "|") {
@@ -2159,6 +2166,8 @@ func isExecuteAction(str string) actionType {
 		return actTrigger
 	case "search":
 		return actSearch
+	case "track", "track-current":
+		return actTrackCurrent
 	}
 	return actIgnore
 }
@@ -2809,8 +2818,18 @@ func parseOptions(index *int, opts *Options, allArgs []string) error {
 			opts.Raw = false
 		case "--track":
 			opts.Track = trackEnabled
+			if ok, str := optionalNextString(); ok {
+				nth, err := splitNth(str)
+				if err != nil {
+					return err
+				}
+				opts.TrackNth = nth
+			} else {
+				opts.TrackNth = nil
+			}
 		case "--no-track":
 			opts.Track = trackDisabled
+			opts.TrackNth = nil
 		case "--tac":
 			opts.Tac = true
 		case "--no-tac":
@@ -314,6 +314,11 @@ type Terminal struct {
 	sort                 bool
 	toggleSort           bool
 	track                trackOption
+	trackNth             []Range
+	trackKey             string
+	trackBlocked         bool
+	trackSync            bool
+	trackKeyCache        map[int32]bool
 	targetIndex          int32
 	delimiter            Delimiter
 	expect               map[tui.Event]string
@@ -1043,6 +1048,7 @@ func NewTerminal(opts *Options, eventBox *util.EventBox, executor *util.Executor
 		sort:               opts.Sort > 0,
 		toggleSort:         opts.ToggleSort,
 		track:              opts.Track,
+		trackNth:           opts.TrackNth,
 		targetIndex:        minItem.Index(),
 		delimiter:          opts.Delimiter,
 		expect:             opts.Expect,
@@ -1893,7 +1899,33 @@ func (t *Terminal) UpdateList(result MatchResult) {
 		t.triggerLoad = false
 		t.eventChan <- tui.Load.AsEvent()
 	}
-	if prevIndex >= 0 {
+	// Search for the tracked item by nth key
+	// - reload (async): search eagerly, unblock as soon as match is found
+	// - reload-sync: wait until stream is complete before searching
+	trackWasBlocked := t.trackBlocked
+	if len(t.trackKey) > 0 && (!t.trackSync || !t.reading) {
+		found := false
+		for i := 0; i < t.merger.Length(); i++ {
+			item := t.merger.Get(i).item
+			idx := item.Index()
+			match, ok := t.trackKeyCache[idx]
+			if !ok {
+				match = t.trackKeyFor(item, t.trackNth) == t.trackKey
+				t.trackKeyCache[idx] = match
+			}
+			if match {
+				t.cy = i
+				if t.track.Current() {
+					t.track.index = idx
+				}
+				found = true
+				break
+			}
+		}
+		if found || !t.reading {
+			t.unblockTrack()
+		}
+	} else if prevIndex >= 0 {
 		pos := t.cy - t.offset
 		count := t.merger.Length()
 		i := t.merger.FindIndex(prevIndex)
@@ -1929,9 +1961,17 @@ func (t *Terminal) UpdateList(result MatchResult) {
 	if t.hasResultActions {
 		t.eventChan <- tui.Result.AsEvent()
 	}
+	updateList := !t.trackBlocked
+	updatePrompt := trackWasBlocked && !t.trackBlocked
 	t.mutex.Unlock()
+
 	t.reqBox.Set(reqInfo, nil)
-	t.reqBox.Set(reqList, nil)
+	if updateList {
+		t.reqBox.Set(reqList, nil)
+	}
+	if updatePrompt {
+		t.reqBox.Set(reqPrompt, nil)
+	}
 	if needActivation {
 		t.reqBox.Set(reqActivate, nil)
 	}
@@ -2880,6 +2920,8 @@ func (t *Terminal) printPrompt() {
 	color := tui.ColInput
 	if t.paused {
 		color = tui.ColDisabled
+	} else if t.trackBlocked {
+		color = color.WithAttr(tui.Dim)
 	}
 	w.CPrint(color, string(before))
 	w.CPrint(color, string(after))
@@ -2971,9 +3013,17 @@ func (t *Terminal) printInfoImpl() {
 		}
 	}
 	if t.track.Global() {
-		output += " +T"
+		if t.trackBlocked {
+			output += " +T*"
+		} else {
+			output += " +T"
+		}
 	} else if t.track.Current() {
-		output += " +t"
+		if t.trackBlocked {
+			output += " +t*"
+		} else {
+			output += " +t"
+		}
 	}
 	if t.multi > 0 {
 		if t.multi == maxMulti {
@@ -5366,6 +5416,22 @@ func (t *Terminal) currentIndex() int32 {
 	return minItem.Index()
 }

+func (t *Terminal) trackKeyFor(item *Item, nth []Range) string {
+	tokens := Tokenize(item.AsString(t.ansi), t.delimiter)
+	return StripLastDelimiter(JoinTokens(Transform(tokens, nth)), t.delimiter)
+}
+
+func (t *Terminal) unblockTrack() {
+	if t.trackBlocked {
+		t.trackBlocked = false
+		t.trackKey = ""
+		t.trackKeyCache = nil
+		if !t.inputless {
+			t.tui.ShowCursor()
+		}
+	}
+}
+
 func (t *Terminal) addClickHeaderWord(env []string) []string {
 	/*
 	 * echo $'HL1\nHL2' | fzf --header-lines 3 --header $'H1\nH2' --header-lines-border --bind 'click-header:preview:env | grep FZF_CLICK'
@@ -6187,6 +6253,14 @@ func (t *Terminal) Loop() error {
 					callback(a.a)
 				}
 			}
+			// When track-blocked, only allow abort/cancel and track-disabling actions
+			if t.trackBlocked && a.t != actToggleTrack && a.t != actToggleTrackCurrent && a.t != actUntrackCurrent {
+				if a.t == actAbort || a.t == actCancel {
+					t.unblockTrack()
+					req(reqPrompt, reqInfo)
+				}
+				return true
+			}
 		Action:
 			switch a.t {
 			case actIgnore, actStart, actClick:
@@ -6958,14 +7032,16 @@ func (t *Terminal) Loop() error {
 				case trackDisabled:
 					t.track = trackEnabled
 				}
-				req(reqInfo)
+				t.unblockTrack()
+				req(reqPrompt, reqInfo)
 			case actToggleTrackCurrent:
 				if t.track.Current() {
 					t.track = trackDisabled
 				} else if t.track.Disabled() {
 					t.track = trackCurrent(t.currentIndex())
 				}
-				req(reqInfo)
+				t.unblockTrack()
+				req(reqPrompt, reqInfo)
 			case actShowHeader:
 				t.headerVisible = true
 				req(reqList, reqInfo, reqPrompt, reqHeader)
@@ -7023,12 +7099,19 @@ func (t *Terminal) Loop() error {
 				if !t.track.Global() {
 					t.track = trackCurrent(t.currentIndex())
 				}
+				// Parse optional nth argument: track-current(1) or track-current(1,3)
+				if len(a.a) > 0 {
+					if nth, err := splitNth(a.a); err == nil {
+						t.trackNth = nth
+					}
+				}
 				req(reqInfo)
 			case actUntrackCurrent:
 				if t.track.Current() {
 					t.track = trackDisabled
 				}
-				req(reqInfo)
+				t.unblockTrack()
+				req(reqPrompt, reqInfo)
 			case actSearch:
 				override := []rune(a.a)
 				t.inputOverride = &override
@@ -7379,6 +7462,20 @@ func (t *Terminal) Loop() error {
 					newCommand = &commandSpec{command, tempFiles}
 					reloadSync = a.t == actReloadSync
 					t.reading = true
+
+					// Capture tracking key before reload
+					if !t.track.Disabled() && len(t.trackNth) > 0 {
+						if item := t.currentItem(); item != nil {
+							t.trackKey = t.trackKeyFor(item, t.trackNth)
+							t.trackKeyCache = make(map[int32]bool)
+							t.trackBlocked = true
+							t.trackSync = reloadSync
+							if !t.inputless {
+								t.tui.HideCursor()
+							}
+							req(reqPrompt, reqInfo)
+						}
+					}
 				}
 			case actUnbind:
 				if keys, _, err := parseKeyChords(a.a, "PANIC"); err == nil {