Provide an option to reverse items only (#1267)

2 files changed, 70 insertions, 20 deletions

diff --git a/src/options.go b/src/options.go
index 45eca5ef..fc32344c 100644
--- a/src/options.go
+++ b/src/options.go
@@ -53,7 +53,7 @@ const usage = `usage: fzf [options]
                           height instead of using fullscreen
     --min-height=HEIGHT   Minimum height when --height is given in percent
                           (default: 10)
-    --reverse             Reverse orientation
+    --layout=LAYOUT       Choose layout: [default|reverse|reverse-list]
     --border              Draw border above and below the finder
     --margin=MARGIN       Screen margin (TRBL / TB,RL / T,RL,B / T,R,B,L)
     --inline-info         Display finder info inline with the query
@@ -90,7 +90,8 @@ const usage = `usage: fzf [options]
 
   Environment variables
     FZF_DEFAULT_COMMAND   Default command to use when input is tty
-    FZF_DEFAULT_OPTS      Default options (e.g. '--reverse --inline-info')
+    FZF_DEFAULT_OPTS      Default options
+                          (e.g. '--layout=reverse --inline-info')
 
 `
 
@@ -132,6 +133,14 @@ const (
 	posRight
 )
 
+type layoutType int
+
+const (
+	layoutDefault layoutType = iota
+	layoutReverse
+	layoutReverseList
+)
+
 type previewOpts struct {
 	command  string
 	position windowPosition
@@ -161,7 +170,7 @@ type Options struct {
 	Bold        bool
 	Height      sizeSpec
 	MinHeight   int
-	Reverse     bool
+	Layout      layoutType
 	Cycle       bool
 	Hscroll     bool
 	HscrollOff  int
@@ -211,7 +220,7 @@ func defaultOptions() *Options {
 		Black:       false,
 		Bold:        true,
 		MinHeight:   10,
-		Reverse:     false,
+		Layout:      layoutDefault,
 		Cycle:       false,
 		Hscroll:     true,
 		HscrollOff:  10,
@@ -857,6 +866,20 @@ func parseHeight(str string) sizeSpec {
 	return size
 }
 
+func parseLayout(str string) layoutType {
+	switch str {
+	case "default":
+		return layoutDefault
+	case "reverse":
+		return layoutReverse
+	case "reverse-list":
+		return layoutReverseList
+	default:
+		errorExit("invalid layout (expected: default / reverse / reverse-list)")
+	}
+	return layoutDefault
+}
+
 func parsePreviewWindow(opts *previewOpts, input string) {
 	// Default
 	opts.position = posRight
@@ -1037,10 +1060,13 @@ func parseOptions(opts *Options, allArgs []string) {
 			opts.Bold = true
 		case "--no-bold":
 			opts.Bold = false
+		case "--layout":
+			opts.Layout = parseLayout(
+				nextString(allArgs, &i, "layout required (default / reverse / reverse-list)"))
 		case "--reverse":
-			opts.Reverse = true
+			opts.Layout = layoutReverse
 		case "--no-reverse":
-			opts.Reverse = false
+			opts.Layout = layoutDefault
 		case "--cycle":
 			opts.Cycle = true
 		case "--no-cycle":
@@ -1156,6 +1182,8 @@ func parseOptions(opts *Options, allArgs []string) {
 				opts.Height = parseHeight(value)
 			} else if match, value := optString(arg, "--min-height="); match {
 				opts.MinHeight = atoi(value)
+			} else if match, value := optString(arg, "--layout="); match {
+				opts.Layout = parseLayout(value)
 			} else if match, value := optString(arg, "--toggle-sort="); match {
 				parseToggleSort(opts.Keymap, value)
 			} else if match, value := optString(arg, "--expect="); match {
diff --git a/src/terminal.go b/src/terminal.go
index 664b7d47..d4685042 100644
--- a/src/terminal.go
+++ b/src/terminal.go
@@ -59,7 +59,7 @@ type Terminal struct {
 	inlineInfo bool
 	prompt     string
 	promptLen  int
-	reverse    bool
+	layout     layoutType
 	fullscreen bool
 	hscroll    bool
 	hscrollOff int
@@ -302,10 +302,11 @@ func trimQuery(query string) []rune {
 func NewTerminal(opts *Options, eventBox *util.EventBox) *Terminal {
 	input := trimQuery(opts.Query)
 	var header []string
-	if opts.Reverse {
-		header = opts.Header
-	} else {
+	switch opts.Layout {
+	case layoutDefault, layoutReverseList:
 		header = reverseStringArray(opts.Header)
+	default:
+		header = opts.Header
 	}
 	var delay time.Duration
 	if opts.Tac {
@@ -363,7 +364,7 @@ func NewTerminal(opts *Options, eventBox *util.EventBox) *Terminal {
 	t := Terminal{
 		initDelay:  delay,
 		inlineInfo: opts.InlineInfo,
-		reverse:    opts.Reverse,
+		layout:     opts.Layout,
 		fullscreen: fullscreen,
 		hscroll:    opts.Hscroll,
 		hscrollOff: opts.HscrollOff,
@@ -643,8 +644,21 @@ func (t *Terminal) resizeWindows() {
 }
 
 func (t *Terminal) move(y int, x int, clear bool) {
-	if !t.reverse {
-		y = t.window.Height() - y - 1
+	h := t.window.Height()
+
+	switch t.layout {
+	case layoutDefault:
+		y = h - y - 1
+	case layoutReverseList:
+		n := 2 + len(t.header)
+		if t.inlineInfo {
+			n--
+		}
+		if y < n {
+			y = h - y - 1
+		} else {
+			y -= n
+		}
 	}
 
 	if clear {
@@ -748,7 +762,7 @@ func (t *Terminal) printList() {
 	count := t.merger.Length() - t.offset
 	for j := 0; j < maxy; j++ {
 		i := j
-		if !t.reverse {
+		if t.layout == layoutDefault {
 			i = maxy - 1 - j
 		}
 		line := i + 2 + len(t.header)
@@ -1680,12 +1694,12 @@ func (t *Terminal) Loop() {
 					req(reqList, reqInfo)
 				}
 			case actToggleIn:
-				if t.reverse {
+				if t.layout != layoutDefault {
 					return doAction(action{t: actToggleUp}, mapkey)
 				}
 				return doAction(action{t: actToggleDown}, mapkey)
 			case actToggleOut:
-				if t.reverse {
+				if t.layout != layoutDefault {
 					return doAction(action{t: actToggleDown}, mapkey)
 				}
 				return doAction(action{t: actToggleUp}, mapkey)
@@ -1813,13 +1827,21 @@ func (t *Terminal) Loop() {
 					mx -= t.window.Left()
 					my -= t.window.Top()
 					mx = util.Constrain(mx-t.promptLen, 0, len(t.input))
-					if !t.reverse {
-						my = t.window.Height() - my - 1
-					}
 					min := 2 + len(t.header)
 					if t.inlineInfo {
 						min--
 					}
+					h := t.window.Height()
+					switch t.layout {
+					case layoutDefault:
+						my = h - my - 1
+					case layoutReverseList:
+						if my < h-min {
+							my += min
+						} else {
+							my = h - my - 1
+						}
+					}
 					if me.Double {
 						// Double-click
 						if my >= min {
@@ -1912,7 +1934,7 @@ func (t *Terminal) constrain() {
 }
 
 func (t *Terminal) vmove(o int, allowCycle bool) {
-	if t.reverse {
+	if t.layout != layoutDefault {
 		o *= -1
 	}
 	dest := t.cy + o