Refactor the code so that fzf can be used as a library (#3769)

7 files changed, 88 insertions, 68 deletions

diff --git a/src/tui/dummy.go b/src/tui/dummy.go
index 7760a724..1a761460 100644
--- a/src/tui/dummy.go
+++ b/src/tui/dummy.go
@@ -8,7 +8,7 @@ func HasFullscreenRenderer() bool {
 	return false
 }
 
-var DefaultBorderShape BorderShape = BorderRounded
+var DefaultBorderShape = BorderRounded
 
 func (a Attr) Merge(b Attr) Attr {
 	return a | b
@@ -29,7 +29,7 @@ const (
 	StrikeThrough = Attr(1 << 7)
 )
 
-func (r *FullscreenRenderer) Init()                              {}
+func (r *FullscreenRenderer) Init() error                        { return nil }
 func (r *FullscreenRenderer) Resize(maxHeightFunc func(int) int) {}
 func (r *FullscreenRenderer) Pause(bool)                         {}
 func (r *FullscreenRenderer) Resume(bool, bool)                  {}
diff --git a/src/tui/eventtype_string.go b/src/tui/eventtype_string.go
index ce34d36e..d752163d 100644
--- a/src/tui/eventtype_string.go
+++ b/src/tui/eventtype_string.go
@@ -83,34 +83,35 @@ func _() {
 	_ = x[Alt-72]
 	_ = x[CtrlAlt-73]
 	_ = x[Invalid-74]
-	_ = x[Mouse-75]
-	_ = x[DoubleClick-76]
-	_ = x[LeftClick-77]
-	_ = x[RightClick-78]
-	_ = x[SLeftClick-79]
-	_ = x[SRightClick-80]
-	_ = x[ScrollUp-81]
-	_ = x[ScrollDown-82]
-	_ = x[SScrollUp-83]
-	_ = x[SScrollDown-84]
-	_ = x[PreviewScrollUp-85]
-	_ = x[PreviewScrollDown-86]
-	_ = x[Resize-87]
-	_ = x[Change-88]
-	_ = x[BackwardEOF-89]
-	_ = x[Start-90]
-	_ = x[Load-91]
-	_ = x[Focus-92]
-	_ = x[One-93]
-	_ = x[Zero-94]
-	_ = x[Result-95]
-	_ = x[Jump-96]
-	_ = x[JumpCancel-97]
+	_ = x[Fatal-75]
+	_ = x[Mouse-76]
+	_ = x[DoubleClick-77]
+	_ = x[LeftClick-78]
+	_ = x[RightClick-79]
+	_ = x[SLeftClick-80]
+	_ = x[SRightClick-81]
+	_ = x[ScrollUp-82]
+	_ = x[ScrollDown-83]
+	_ = x[SScrollUp-84]
+	_ = x[SScrollDown-85]
+	_ = x[PreviewScrollUp-86]
+	_ = x[PreviewScrollDown-87]
+	_ = x[Resize-88]
+	_ = x[Change-89]
+	_ = x[BackwardEOF-90]
+	_ = x[Start-91]
+	_ = x[Load-92]
+	_ = x[Focus-93]
+	_ = x[One-94]
+	_ = x[Zero-95]
+	_ = x[Result-96]
+	_ = x[Jump-97]
+	_ = x[JumpCancel-98]
 }
 
-const _EventType_name = "RuneCtrlACtrlBCtrlCCtrlDCtrlECtrlFCtrlGCtrlHTabCtrlJCtrlKCtrlLCtrlMCtrlNCtrlOCtrlPCtrlQCtrlRCtrlSCtrlTCtrlUCtrlVCtrlWCtrlXCtrlYCtrlZEscCtrlSpaceCtrlDeleteCtrlBackSlashCtrlRightBracketCtrlCaretCtrlSlashShiftTabBackspaceDeletePageUpPageDownUpDownLeftRightHomeEndInsertShiftUpShiftDownShiftLeftShiftRightShiftDeleteF1F2F3F4F5F6F7F8F9F10F11F12AltBackspaceAltUpAltDownAltLeftAltRightAltShiftUpAltShiftDownAltShiftLeftAltShiftRightAltCtrlAltInvalidMouseDoubleClickLeftClickRightClickSLeftClickSRightClickScrollUpScrollDownSScrollUpSScrollDownPreviewScrollUpPreviewScrollDownResizeChangeBackwardEOFStartLoadFocusOneZeroResultJumpJumpCancel"
+const _EventType_name = "RuneCtrlACtrlBCtrlCCtrlDCtrlECtrlFCtrlGCtrlHTabCtrlJCtrlKCtrlLCtrlMCtrlNCtrlOCtrlPCtrlQCtrlRCtrlSCtrlTCtrlUCtrlVCtrlWCtrlXCtrlYCtrlZEscCtrlSpaceCtrlDeleteCtrlBackSlashCtrlRightBracketCtrlCaretCtrlSlashShiftTabBackspaceDeletePageUpPageDownUpDownLeftRightHomeEndInsertShiftUpShiftDownShiftLeftShiftRightShiftDeleteF1F2F3F4F5F6F7F8F9F10F11F12AltBackspaceAltUpAltDownAltLeftAltRightAltShiftUpAltShiftDownAltShiftLeftAltShiftRightAltCtrlAltInvalidFatalMouseDoubleClickLeftClickRightClickSLeftClickSRightClickScrollUpScrollDownSScrollUpSScrollDownPreviewScrollUpPreviewScrollDownResizeChangeBackwardEOFStartLoadFocusOneZeroResultJumpJumpCancel"
 
-var _EventType_index = [...]uint16{0, 4, 9, 14, 19, 24, 29, 34, 39, 44, 47, 52, 57, 62, 67, 72, 77, 82, 87, 92, 97, 102, 107, 112, 117, 122, 127, 132, 135, 144, 154, 167, 183, 192, 201, 209, 218, 224, 230, 238, 240, 244, 248, 253, 257, 260, 266, 273, 282, 291, 301, 312, 314, 316, 318, 320, 322, 324, 326, 328, 330, 333, 336, 339, 351, 356, 363, 370, 378, 388, 400, 412, 425, 428, 435, 442, 447, 458, 467, 477, 487, 498, 506, 516, 525, 536, 551, 568, 574, 580, 591, 596, 600, 605, 608, 612, 618, 622, 632}
+var _EventType_index = [...]uint16{0, 4, 9, 14, 19, 24, 29, 34, 39, 44, 47, 52, 57, 62, 67, 72, 77, 82, 87, 92, 97, 102, 107, 112, 117, 122, 127, 132, 135, 144, 154, 167, 183, 192, 201, 209, 218, 224, 230, 238, 240, 244, 248, 253, 257, 260, 266, 273, 282, 291, 301, 312, 314, 316, 318, 320, 322, 324, 326, 328, 330, 333, 336, 339, 351, 356, 363, 370, 378, 388, 400, 412, 425, 428, 435, 442, 447, 452, 463, 472, 482, 492, 503, 511, 521, 530, 541, 556, 573, 579, 585, 596, 601, 605, 610, 613, 617, 623, 627, 637}
 
 func (i EventType) String() string {
 	if i < 0 || i >= EventType(len(_EventType_index)-1) {
diff --git a/src/tui/light.go b/src/tui/light.go
index a045b783..3ef8b60e 100644
--- a/src/tui/light.go
+++ b/src/tui/light.go
@@ -2,6 +2,7 @@ package tui
 
 import (
 	"bytes"
+	"errors"
 	"fmt"
 	"os"
 	"regexp"
@@ -10,6 +11,7 @@ import (
 	"time"
 	"unicode/utf8"
 
+	"github.com/junegunn/fzf/src/util"
 	"github.com/rivo/uniseg"
 
 	"golang.org/x/term"
@@ -27,8 +29,8 @@ const (
 
 const consoleDevice string = "/dev/tty"
 
-var offsetRegexp *regexp.Regexp = regexp.MustCompile("(.*)\x1b\\[([0-9]+);([0-9]+)R")
-var offsetRegexpBegin *regexp.Regexp = regexp.MustCompile("^\x1b\\[[0-9]+;[0-9]+R")
+var offsetRegexp = regexp.MustCompile("(.*)\x1b\\[([0-9]+);([0-9]+)R")
+var offsetRegexpBegin = regexp.MustCompile("^\x1b\\[[0-9]+;[0-9]+R")
 
 func (r *LightRenderer) PassThrough(str string) {
 	r.queued.WriteString("\x1b7" + str + "\x1b8")
@@ -78,6 +80,7 @@ func (r *LightRenderer) flush() {
 
 // Light renderer
 type LightRenderer struct {
+	closed        *util.AtomicBool
 	theme         *ColorTheme
 	mouse         bool
 	forceBlack    bool
@@ -123,19 +126,24 @@ type LightWindow struct {
 	bg       Color
 }
 
-func NewLightRenderer(theme *ColorTheme, forceBlack bool, mouse bool, tabstop int, clearOnExit bool, fullscreen bool, maxHeightFunc func(int) int) Renderer {
+func NewLightRenderer(theme *ColorTheme, forceBlack bool, mouse bool, tabstop int, clearOnExit bool, fullscreen bool, maxHeightFunc func(int) int) (Renderer, error) {
+	in, err := openTtyIn()
+	if err != nil {
+		return nil, err
+	}
 	r := LightRenderer{
+		closed:        util.NewAtomicBool(false),
 		theme:         theme,
 		forceBlack:    forceBlack,
 		mouse:         mouse,
 		clearOnExit:   clearOnExit,
-		ttyin:         openTtyIn(),
+		ttyin:         in,
 		yoffset:       0,
 		tabstop:       tabstop,
 		fullscreen:    fullscreen,
 		upOneLine:     false,
 		maxHeightFunc: maxHeightFunc}
-	return &r
+	return &r, nil
 }
 
 func repeat(r rune, times int) string {
@@ -153,11 +161,11 @@ func atoi(s string, defaultValue int) int {
 	return value
 }
 
-func (r *LightRenderer) Init() {
+func (r *LightRenderer) Init() error {
 	r.escDelay = atoi(os.Getenv("ESCDELAY"), defaultEscDelay)
 
 	if err := r.initPlatform(); err != nil {
-		errorExit(err.Error())
+		return err
 	}
 	r.updateTerminalSize()
 	initTheme(r.theme, r.defaultTheme(), r.forceBlack)
@@ -195,6 +203,7 @@ func (r *LightRenderer) Init() {
 	if !r.fullscreen && r.mouse {
 		r.yoffset, _ = r.findOffset()
 	}
+	return nil
 }
 
 func (r *LightRenderer) Resize(maxHeightFunc func(int) int) {
@@ -233,15 +242,16 @@ func getEnv(name string, defaultValue int) int {
 	return atoi(env, defaultValue)
 }
 
-func (r *LightRenderer) getBytes() []byte {
-	return r.getBytesInternal(r.buffer, false)
+func (r *LightRenderer) getBytes() ([]byte, error) {
+	bytes, err := r.getBytesInternal(r.buffer, false)
+	return bytes, err
 }
 
-func (r *LightRenderer) getBytesInternal(buffer []byte, nonblock bool) []byte {
+func (r *LightRenderer) getBytesInternal(buffer []byte, nonblock bool) ([]byte, error) {
 	c, ok := r.getch(nonblock)
 	if !nonblock && !ok {
 		r.Close()
-		errorExit("Failed to read " + consoleDevice)
+		return nil, errors.New("failed to read " + consoleDevice)
 	}
 
 	retries := 0
@@ -272,19 +282,23 @@ func (r *LightRenderer) getBytesInternal(buffer []byte, nonblock bool) []byte {
 		// so terminate fzf immediately.
 		if len(buffer) > maxInputBuffer {
 			r.Close()
-			panic(fmt.Sprintf("Input buffer overflow (%d): %v", len(buffer), buffer))
+			return nil, fmt.Errorf("input buffer overflow (%d): %v", len(buffer), buffer)
 		}
 	}
 
-	return buffer
+	return buffer, nil
 }
 
 func (r *LightRenderer) GetChar() Event {
+	var err error
 	if len(r.buffer) == 0 {
-		r.buffer = r.getBytes()
+		r.buffer, err = r.getBytes()
+		if err != nil {
+			return Event{Fatal, 0, nil}
+		}
 	}
 	if len(r.buffer) == 0 {
-		panic("Empty buffer")
+		return Event{Fatal, 0, nil}
 	}
 
 	sz := 1
@@ -315,7 +329,9 @@ func (r *LightRenderer) GetChar() Event {
 		ev := r.escSequence(&sz)
 		// Second chance
 		if ev.Type == Invalid {
-			r.buffer = r.getBytes()
+			if r.buffer, err = r.getBytes(); err != nil {
+				return Event{Fatal, 0, nil}
+			}
 			ev = r.escSequence(&sz)
 		}
 		return ev
@@ -738,6 +754,7 @@ func (r *LightRenderer) Close() {
 	r.flush()
 	r.closePlatform()
 	r.restoreTerminal()
+	r.closed.Set(true)
 }
 
 func (r *LightRenderer) Top() int {
diff --git a/src/tui/light_unix.go b/src/tui/light_unix.go
index 55e2b246..a5499a00 100644
--- a/src/tui/light_unix.go
+++ b/src/tui/light_unix.go
@@ -3,7 +3,7 @@
 package tui
 
 import (
-	"fmt"
+	"errors"
 	"os"
 	"os/exec"
 	"strings"
@@ -48,19 +48,18 @@ func (r *LightRenderer) closePlatform() {
 	// NOOP
 }
 
-func openTtyIn() *os.File {
+func openTtyIn() (*os.File, error) {
 	in, err := os.OpenFile(consoleDevice, syscall.O_RDONLY, 0)
 	if err != nil {
 		tty := ttyname()
 		if len(tty) > 0 {
 			if in, err := os.OpenFile(tty, syscall.O_RDONLY, 0); err == nil {
-				return in
+				return in, nil
 			}
 		}
-		fmt.Fprintln(os.Stderr, "Failed to open "+consoleDevice)
-		util.Exit(2)
+		return nil, errors.New("failed to open " + consoleDevice)
 	}
-	return in
+	return in, nil
 }
 
 func (r *LightRenderer) setupTerminal() {
@@ -86,9 +85,14 @@ func (r *LightRenderer) updateTerminalSize() {
 func (r *LightRenderer) findOffset() (row int, col int) {
 	r.csi("6n")
 	r.flush()
+	var err error
 	bytes := []byte{}
 	for tries := 0; tries < offsetPollTries; tries++ {
-		bytes = r.getBytesInternal(bytes, tries > 0)
+		bytes, err = r.getBytesInternal(bytes, tries > 0)
+		if err != nil {
+			return -1, -1
+		}
+
 		offsets := offsetRegexp.FindSubmatch(bytes)
 		if len(offsets) > 3 {
 			// Add anything we skipped over to the input buffer
diff --git a/src/tui/light_windows.go b/src/tui/light_windows.go
index 62b10c12..635b8926 100644
--- a/src/tui/light_windows.go
+++ b/src/tui/light_windows.go
@@ -72,7 +72,7 @@ func (r *LightRenderer) initPlatform() error {
 	go func() {
 		fd := int(r.inHandle)
 		b := make([]byte, 1)
-		for {
+		for !r.closed.Get() {
 			// HACK: if run from PSReadline, something resets ConsoleMode to remove ENABLE_VIRTUAL_TERMINAL_INPUT.
 			_ = windows.SetConsoleMode(windows.Handle(r.inHandle), consoleFlagsInput)
 
@@ -91,9 +91,9 @@ func (r *LightRenderer) closePlatform() {
 	windows.SetConsoleMode(windows.Handle(r.inHandle), r.origStateInput)
 }
 
-func openTtyIn() *os.File {
+func openTtyIn() (*os.File, error) {
 	// not used
-	return nil
+	return nil, nil
 }
 
 func (r *LightRenderer) setupTerminal() error {
diff --git a/src/tui/tcell.go b/src/tui/tcell.go
index 9b8f8620..16ce452d 100644
--- a/src/tui/tcell.go
+++ b/src/tui/tcell.go
@@ -7,7 +7,6 @@ import (
 	"time"
 
 	"github.com/gdamore/tcell/v2"
-	"github.com/gdamore/tcell/v2/encoding"
 	"github.com/junegunn/fzf/src/util"
 
 	"github.com/rivo/uniseg"
@@ -146,13 +145,13 @@ var (
 	_initialResize   bool = true
 )
 
-func (r *FullscreenRenderer) initScreen() {
+func (r *FullscreenRenderer) initScreen() error {
 	s, e := tcell.NewScreen()
 	if e != nil {
-		errorExit(e.Error())
+		return e
 	}
 	if e = s.Init(); e != nil {
-		errorExit(e.Error())
+		return e
 	}
 	if r.mouse {
 		s.EnableMouse()
@@ -160,16 +159,21 @@ func (r *FullscreenRenderer) initScreen() {
 		s.DisableMouse()
 	}
 	_screen = s
+
+	return nil
 }
 
-func (r *FullscreenRenderer) Init() {
+func (r *FullscreenRenderer) Init() error {
 	if os.Getenv("TERM") == "cygwin" {
 		os.Setenv("TERM", "")
 	}
-	encoding.Register()
 
-	r.initScreen()
+	if err := r.initScreen(); err != nil {
+		return err
+	}
 	initTheme(r.theme, r.defaultTheme(), r.forceBlack)
+
+	return nil
 }
 
 func (r *FullscreenRenderer) Top() int {
diff --git a/src/tui/tui.go b/src/tui/tui.go
index a56edc7f..e4858c66 100644
--- a/src/tui/tui.go
+++ b/src/tui/tui.go
@@ -1,8 +1,6 @@
 package tui
 
 import (
-	"fmt"
-	"os"
 	"strconv"
 	"time"
 
@@ -104,6 +102,7 @@ const (
 	CtrlAlt
 
 	Invalid
+	Fatal
 
 	Mouse
 	DoubleClick
@@ -525,7 +524,7 @@ type TermSize struct {
 }
 
 type Renderer interface {
-	Init()
+	Init() error
 	Resize(maxHeightFunc func(int) int)
 	Pause(clear bool)
 	Resume(clear bool, sigcont bool)
@@ -685,11 +684,6 @@ func NoColorTheme() *ColorTheme {
 	}
 }
 
-func errorExit(message string) {
-	fmt.Fprintln(os.Stderr, message)
-	util.Exit(2)
-}
-
 func init() {
 	Default16 = &ColorTheme{
 		Colored:          true,