Enable closing of fuzzyfinder from the caller by passing context (#165)

* Enable closing of fuzzyfinder from the caller by passing context

* Remove unused quit channel

* Use ctx.Err

* Update fuzzyfinder.go

Co-authored-by: ktr <ktr@syfm.me>

Co-authored-by: ktr <ktr@syfm.me>

fuzzyfinder.go

@@ -76,6 +76,8 @@ type finder struct {
 	drawTimer *time.Timer
 	eventCh   chan struct{}
 	opt       *opt
+
+	termEventsChan <-chan tcell.Event
 }
 
 func newFinder() *finder {
@@ -94,6 +96,10 @@ func (f *finder) initFinder(items []string, matched []matching.Matched, opt opt)
 		if err := f.term.Init(); err != nil {
 			return errors.Wrap(err, "failed to initialize screen")
 		}
+
+		eventsChan := make(chan tcell.Event)
+		go f.term.ChannelEvents(eventsChan, nil)
+		f.termEventsChan = eventsChan
 	}
 
 	f.opt = &opt
@@ -442,9 +448,10 @@ func (f *finder) draw(d time.Duration) {
 }
 
 // readKey reads a key input.
-// It returns ErrAbort if esc, CTRL-C or CTRL-D keys are inputted.
-// Also, it returns errEntered if enter key is inputted.
-func (f *finder) readKey() error {
+// It returns ErrAbort if esc, CTRL-C or CTRL-D keys are inputted,
+// errEntered in case of enter key, and a context error when the passed
+// context is cancelled.
+func (f *finder) readKey(ctx context.Context) error {
 	f.stateMu.RLock()
 	prevInputLen := len(f.state.input)
 	f.stateMu.RUnlock()
@@ -457,7 +464,15 @@ func (f *finder) readKey() error {
 		}
 	}()
 
-	e := f.term.PollEvent()
+	var e tcell.Event
+
+	select {
+	case ee := <-f.termEventsChan:
+		e = ee
+	case <-ctx.Done():
+		return ctx.Err()
+	}
+
 	f.stateMu.Lock()
 	defer f.stateMu.Unlock()
 
@@ -670,7 +685,14 @@ func (f *finder) find(slice interface{}, itemFunc func(i int) string, opts []Opt
 		matched []matching.Matched
 	)
 
-	ctx, cancel := context.WithCancel(context.Background())
+	var parentContext context.Context
+	if opt.context != nil {
+		parentContext = opt.context
+	} else {
+		parentContext = context.Background()
+	}
+
+	ctx, cancel := context.WithCancel(parentContext)
 	defer cancel()
 
 	inited := make(chan struct{})
@@ -727,40 +749,45 @@ func (f *finder) find(slice interface{}, itemFunc func(i int) string, opts []Opt
 	}()
 
 	for {
-		f.draw(10 * time.Millisecond)
-
-		err := f.readKey()
-		// hack for earning time to filter exec
-		if isInTesting() {
-			time.Sleep(50 * time.Millisecond)
-		}
-		switch {
-		case errors.Is(err, ErrAbort):
-			return nil, ErrAbort
-		case errors.Is(err, errEntered):
-			f.stateMu.RLock()
-			defer f.stateMu.RUnlock()
+		select {
+		case <-ctx.Done():
+			return nil, ctx.Err()
+		default:
+			f.draw(10 * time.Millisecond)
 
-			if len(f.state.matched) == 0 {
-				return nil, ErrAbort
+			err := f.readKey(ctx)
+			// hack for earning time to filter exec
+			if isInTesting() {
+				time.Sleep(50 * time.Millisecond)
 			}
-			if f.opt.multi {
-				if len(f.state.selection) == 0 {
-					return []int{f.state.matched[f.state.y].Idx}, nil
+			switch {
+			case errors.Is(err, ErrAbort):
+				return nil, ErrAbort
+			case errors.Is(err, errEntered):
+				f.stateMu.RLock()
+				defer f.stateMu.RUnlock()
+
+				if len(f.state.matched) == 0 {
+					return nil, ErrAbort
 				}
-				poss, idxs := make([]int, 0, len(f.state.selection)), make([]int, 0, len(f.state.selection))
-				for idx, pos := range f.state.selection {
-					idxs = append(idxs, idx)
-					poss = append(poss, pos)
+				if f.opt.multi {
+					if len(f.state.selection) == 0 {
+						return []int{f.state.matched[f.state.y].Idx}, nil
+					}
+					poss, idxs := make([]int, 0, len(f.state.selection)), make([]int, 0, len(f.state.selection))
+					for idx, pos := range f.state.selection {
+						idxs = append(idxs, idx)
+						poss = append(poss, pos)
+					}
+					sort.Slice(idxs, func(i, j int) bool {
+						return poss[i] < poss[j]
+					})
+					return idxs, nil
 				}
-				sort.Slice(idxs, func(i, j int) bool {
-					return poss[i] < poss[j]
-				})
-				return idxs, nil
+				return []int{f.state.matched[f.state.y].Idx}, nil
+			case err != nil:
+				return nil, errors.Wrap(err, "failed to read a key")
 			}
-			return []int{f.state.matched[f.state.y].Idx}, nil
-		case err != nil:
-			return nil, errors.Wrap(err, "failed to read a key")
 		}
 	}
 }

fuzzyfinder_test.go

@@ -1,6 +1,7 @@
 package fuzzyfinder_test
 
 import (
+	"context"
 	"flag"
 	"io/ioutil"
 	"log"
@@ -445,6 +446,33 @@ func TestFind_WithPreviewWindow(t *testing.T) {
 	}
 }
 
+func TestFind_withContext(t *testing.T) {
+	t.Parallel()
+
+	f, term := fuzzyfinder.NewWithMockedTerminal()
+	events := append(runes("adrena"), keys(input{tcell.KeyEsc, rune(tcell.KeyEsc), tcell.ModNone})...)
+	term.SetEventsV2(events...)
+
+	cancelledCtx, cancelFunc := context.WithCancel(context.Background())
+	cancelFunc()
+
+	assertWithGolden(t, func(t *testing.T) string {
+		_, err := f.Find(
+			tracks,
+			func(i int) string {
+				return tracks[i].Name
+			},
+			fuzzyfinder.WithContext(cancelledCtx),
+		)
+		if !errors.Is(err, context.Canceled) {
+			t.Fatalf("Find must return ErrAbort, but got '%s'", err)
+		}
+
+		res := term.GetResult()
+		return res
+	})
+}
+
 func TestFind_error(t *testing.T) {
 	t.Parallel()
 

helper_test.go

@@ -1,12 +1,20 @@
 package fuzzyfinder
 
+import "github.com/gdamore/tcell/v2"
+
 func New() *finder {
 	return &finder{}
 }
 
 func NewWithMockedTerminal() (*finder, *TerminalMock) {
+	eventsChan := make(chan tcell.Event, 10)
+
 	f := New()
+	f.termEventsChan = eventsChan
+
 	m := f.UseMockedTerminalV2()
+	go m.ChannelEvents(eventsChan, nil)
+
 	w, h := 60, 10 // A normally value.
 	m.SetSize(w, h)
 	return f, m

option.go

@@ -1,6 +1,9 @@
 package fuzzyfinder
 
-import "sync"
+import (
+	"context"
+	"sync"
+)
 
 type opt struct {
 	mode          mode
@@ -11,6 +14,7 @@ type opt struct {
 	promptString  string
 	header        string
 	beginAtTop    bool
+	context       context.Context
 }
 
 type mode int
@@ -27,7 +31,7 @@ const (
 )
 
 var defaultOption = opt{
-	promptString: "> ",
+	promptString:  "> ",
 	hotReloadLock: &sync.Mutex{}, // this won't resolve the race condition but avoid nil panic
 }
 
@@ -69,7 +73,7 @@ func WithHotReload() Option {
 // The caller must pass a pointer of the slice instead of the slice itself.
 // The caller must pass a RLock which is used to synchronize access to the slice.
 // The caller MUST NOT lock in the itemFunc passed to Find / FindMulti because it will be locked by the fuzzyfinder.
-// If used together with WithPreviewWindow, the caller MUST use the RLock only in the previewFunc passed to WithPreviewWindow. 
+// If used together with WithPreviewWindow, the caller MUST use the RLock only in the previewFunc passed to WithPreviewWindow.
 func WithHotReloadLock(lock sync.Locker) Option {
 	return func(o *opt) {
 		o.hotReload = true
@@ -116,3 +120,10 @@ func WithHeader(s string) Option {
 		o.header = s
 	}
 }
+
+// WithContext enables closing the fuzzy finder from parent.
+func WithContext(ctx context.Context) Option {
+	return func(o *opt) {
+		o.context = ctx
+	}
+}

testdata/fixtures/testfind_withcontext.golden

@@ -0,0 +1,11 @@
+
+
+
+
+
+
+
+
+
+
+