some refactoring in anticipation of the graph feature

vendor/github.com/jesseduffield/gocui/gui.go

@@ -6,7 +6,6 @@ package gocui
 
 import (
 	standardErrors "errors"
-	"fmt"
 	"log"
 	"runtime"
 	"strings"
@@ -76,6 +75,8 @@ type GuiMutexes struct {
 	tickingMutex sync.Mutex
 
 	ViewsMutex sync.Mutex
+
+	drawMutex sync.Mutex
 }
 
 type PlayMode int
@@ -166,14 +167,14 @@ type Gui struct {
 }
 
 // NewGui returns a new Gui object with a given output mode.
-func NewGui(mode OutputMode, supportOverlaps bool, playMode PlayMode, headless bool) (*Gui, error) {
+func NewGui(mode OutputMode, supportOverlaps bool, playMode PlayMode, headless bool, runeReplacements map[rune]string) (*Gui, error) {
 	g := &Gui{}
 
 	var err error
 	if headless {
 		err = g.tcellInitSimulation()
 	} else {
-		err = g.tcellInit()
+		err = g.tcellInit(runeReplacements)
 	}
 	if err != nil {
 		return nil, err
@@ -664,79 +665,6 @@ func (g *Gui) onResize() {
 	// g.screen.Sync()
 }
 
-// flush updates the gui, re-drawing frames and buffers.
-func (g *Gui) flush() error {
-	// pretty sure we don't need this, but keeping it here in case we get weird visual artifacts
-	// g.clear(g.FgColor, g.BgColor)
-
-	maxX, maxY := Screen.Size()
-	// if GUI's size has changed, we need to redraw all views
-	if maxX != g.maxX || maxY != g.maxY {
-		for _, v := range g.views {
-			v.clearViewLines()
-		}
-	}
-	g.maxX, g.maxY = maxX, maxY
-
-	for _, m := range g.managers {
-		if err := m.Layout(g); err != nil {
-			return err
-		}
-	}
-	for _, v := range g.views {
-		if !v.Visible || v.y1 < v.y0 {
-			continue
-		}
-		if v.Frame {
-			var fgColor, bgColor, frameColor Attribute
-			if g.Highlight && v == g.currentView {
-				fgColor = g.SelFgColor
-				bgColor = g.SelBgColor
-				frameColor = g.SelFrameColor
-			} else {
-				bgColor = g.BgColor
-				if v.TitleColor != ColorDefault {
-					fgColor = v.TitleColor
-				} else {
-					fgColor = g.FgColor
-				}
-				if v.FrameColor != ColorDefault {
-					frameColor = v.FrameColor
-				} else {
-					frameColor = g.FrameColor
-				}
-			}
-
-			if err := g.drawFrameEdges(v, frameColor, bgColor); err != nil {
-				return err
-			}
-			if err := g.drawFrameCorners(v, frameColor, bgColor); err != nil {
-				return err
-			}
-			if v.Title != "" || len(v.Tabs) > 0 {
-				if err := g.drawTitle(v, fgColor, bgColor); err != nil {
-					return err
-				}
-			}
-			if v.Subtitle != "" {
-				if err := g.drawSubtitle(v, fgColor, bgColor); err != nil {
-					return err
-				}
-			}
-			if v.ContainsList && g.ShowListFooter {
-				if err := g.drawListFooter(v, fgColor, bgColor); err != nil {
-					return err
-				}
-			}
-		}
-		if err := g.draw(v); err != nil {
-			return err
-		}
-	}
-	Screen.Show()
-	return nil
-}
-
 func (g *Gui) clear(fg, bg Attribute) (int, int) {
 	st := getTcellStyle(oldStyle{fg: fg, bg: bg, outputMode: g.outputMode})
 	w, h := Screen.Size()
@@ -983,7 +911,7 @@ func (g *Gui) drawListFooter(v *View, fgColor, bgColor Attribute) error {
 		return nil
 	}
 
-	message := fmt.Sprintf("%d of %d", v.cy+v.oy+1, len(v.lines))
+	message := v.Footer
 
 	if v.y1 < 0 || v.y1 >= g.maxY {
 		return nil
@@ -1006,12 +934,102 @@ func (g *Gui) drawListFooter(v *View, fgColor, bgColor Attribute) error {
 	return nil
 }
 
+// flush updates the gui, re-drawing frames and buffers.
+func (g *Gui) flush() error {
+	g.Mutexes.drawMutex.Lock()
+	defer g.Mutexes.drawMutex.Unlock()
+
+	// pretty sure we don't need this, but keeping it here in case we get weird visual artifacts
+	// g.clear(g.FgColor, g.BgColor)
+
+	maxX, maxY := Screen.Size()
+	// if GUI's size has changed, we need to redraw all views
+	if maxX != g.maxX || maxY != g.maxY {
+		for _, v := range g.views {
+			v.clearViewLines()
+		}
+	}
+	g.maxX, g.maxY = maxX, maxY
+
+	for _, m := range g.managers {
+		if err := m.Layout(g); err != nil {
+			return err
+		}
+	}
+	for _, v := range g.views {
+		if err := g.draw(v); err != nil {
+			return err
+		}
+	}
+
+	Screen.Show()
+	return nil
+}
+
+func (g *Gui) Draw(v *View) error {
+	g.Mutexes.drawMutex.Lock()
+	defer g.Mutexes.drawMutex.Unlock()
+
+	if err := g.draw(v); err != nil {
+		return err
+	}
+
+	Screen.Show()
+	return nil
+}
+
 // draw manages the cursor and calls the draw function of a view.
 func (g *Gui) draw(v *View) error {
 	if g.suspended {
 		return nil
 	}
 
+	if !v.Visible || v.y1 < v.y0 {
+		return nil
+	}
+	if v.Frame {
+		var fgColor, bgColor, frameColor Attribute
+		if g.Highlight && v == g.currentView {
+			fgColor = g.SelFgColor
+			bgColor = g.SelBgColor
+			frameColor = g.SelFrameColor
+		} else {
+			bgColor = g.BgColor
+			if v.TitleColor != ColorDefault {
+				fgColor = v.TitleColor
+			} else {
+				fgColor = g.FgColor
+			}
+			if v.FrameColor != ColorDefault {
+				frameColor = v.FrameColor
+			} else {
+				frameColor = g.FrameColor
+			}
+		}
+
+		if err := g.drawFrameEdges(v, frameColor, bgColor); err != nil {
+			return err
+		}
+		if err := g.drawFrameCorners(v, frameColor, bgColor); err != nil {
+			return err
+		}
+		if v.Title != "" || len(v.Tabs) > 0 {
+			if err := g.drawTitle(v, fgColor, bgColor); err != nil {
+				return err
+			}
+		}
+		if v.Subtitle != "" {
+			if err := g.drawSubtitle(v, fgColor, bgColor); err != nil {
+				return err
+			}
+		}
+		if v.Footer != "" && g.ShowListFooter {
+			if err := g.drawListFooter(v, fgColor, bgColor); err != nil {
+				return err
+			}
+		}
+	}
+
 	if g.Cursor {
 		if curview := g.currentView; curview != nil {
 			vMaxX, vMaxY := curview.Size()

vendor/github.com/jesseduffield/gocui/tcell_driver.go

@@ -26,6 +26,10 @@ var runeReplacements = map[rune]string{
 	'┐': "+",
 	'└': "+",
 	'┘': "+",
+	'╭': "+",
+	'╮': "+",
+	'╰': "+",
+	'╯': "+",
 	'─': "-",
 
 	// using a hyphen here actually looks weird.
@@ -33,6 +37,9 @@ var runeReplacements = map[rune]string{
 	'╶': " ",
 	'╴': " ",
 
+	'┴': "+",
+	'┬': "+",
+	'╷': "|",
 	'├': "+",
 	'│': "|",
 	'▼': "v",
@@ -42,7 +49,7 @@ var runeReplacements = map[rune]string{
 }
 
 // tcellInit initializes tcell screen for use.
-func (g *Gui) tcellInit() error {
+func (g *Gui) tcellInit(runeReplacements map[rune]string) error {
 	runewidth.DefaultCondition.EastAsianWidth = false
 	tcell.SetEncodingFallback(tcell.EncodingFallbackASCII)
 
@@ -51,7 +58,7 @@ func (g *Gui) tcellInit() error {
 	} else if e = s.Init(); e != nil {
 		return e
 	} else {
-		registerRuneFallbacks(s)
+		registerRuneFallbacks(s, runeReplacements)
 
 		g.screen = s
 		Screen = s
@@ -59,10 +66,14 @@ func (g *Gui) tcellInit() error {
 	}
 }
 
-func registerRuneFallbacks(s tcell.Screen) {
+func registerRuneFallbacks(s tcell.Screen, additional map[rune]string) {
 	for before, after := range runeReplacements {
 		s.RegisterRuneFallback(before, after)
 	}
+
+	for before, after := range additional {
+		s.RegisterRuneFallback(before, after)
+	}
 }
 
 // tcellInitSimulation initializes tcell screen for use.

vendor/github.com/jesseduffield/gocui/view.go

@@ -153,14 +153,14 @@ type View struct {
 
 	searcher *searcher
 
-	// when ContainsList is true, we show the current index and total count in the view
-	ContainsList bool
-
 	// KeybindOnEdit should be set to true when you want to execute keybindings even when the view is editable
 	// (this is usually not the case)
 	KeybindOnEdit bool
 
 	TextArea *TextArea
+
+	// something like '1 of 20' for a list view
+	Footer string
 }
 
 // call this in the event of a view resize, or if you want to render new content
@@ -372,11 +372,21 @@ func (v *View) Height() int {
 
 // if a view has a frame, that leaves less space for its writeable area
 func (v *View) InnerWidth() int {
-	return v.Width() - v.frameOffset()
+	innerWidth := v.Width() - v.frameOffset()
+	if innerWidth < 0 {
+		return 0
+	}
+
+	return innerWidth
 }
 
 func (v *View) InnerHeight() int {
-	return v.Height() - v.frameOffset()
+	innerHeight := v.Height() - v.frameOffset()
+	if innerHeight < 0 {
+		return 0
+	}
+
+	return innerHeight
 }
 
 func (v *View) frameOffset() int {
@@ -563,8 +573,6 @@ func (v *View) Write(p []byte) (n int, err error) {
 	v.writeMutex.Lock()
 	defer v.writeMutex.Unlock()
 
-	v.tainted = true
-	v.makeWriteable(v.wx, v.wy)
 	v.writeRunes(bytes.Runes(p))
 
 	return len(p), nil
@@ -574,20 +582,16 @@ func (v *View) WriteRunes(p []rune) {
 	v.writeMutex.Lock()
 	defer v.writeMutex.Unlock()
 
+	v.writeRunes(p)
+}
+
+// writeRunes copies slice of runes into internal lines buffer.
+func (v *View) writeRunes(p []rune) {
 	v.tainted = true
 
 	// Fill with empty cells, if writing outside current view buffer
 	v.makeWriteable(v.wx, v.wy)
-	v.writeRunes(p)
-}
 
-func (v *View) WriteString(s string) {
-	v.WriteRunes([]rune(s))
-}
-
-// writeRunes copies slice of runes into internal lines buffer.
-// caller must make sure that writing position is accessable.
-func (v *View) writeRunes(p []rune) {
 	for _, r := range p {
 		switch r {
 		case '\n':
@@ -613,6 +617,16 @@ func (v *View) writeRunes(p []rune) {
 	}
 }
 
+// exported functions use the mutex. Non-exported functions are for internal use
+// and a calling function should use a mutex
+func (v *View) WriteString(s string) {
+	v.WriteRunes([]rune(s))
+}
+
+func (v *View) writeString(s string) {
+	v.writeRunes([]rune(s))
+}
+
 // parseInput parses char by char the input written to the View. It returns nil
 // while processing ESC sequences. Otherwise, it returns a cell slice that
 // contains the processed data.
@@ -696,16 +710,28 @@ func (v *View) Read(p []byte) (n int, err error) {
 	return offset, io.EOF
 }
 
+// only use this if the calling function has a lock on writeMutex
+func (v *View) clear() {
+	v.rewind()
+	v.lines = nil
+	v.clearViewLines()
+}
+
 // Clear empties the view's internal buffer.
 // And resets reading and writing offsets.
 func (v *View) Clear() {
 	v.writeMutex.Lock()
 	defer v.writeMutex.Unlock()
 
-	v.rewind()
-	v.lines = nil
-	v.clearViewLines()
-	v.clearRunes()
+	v.clear()
+}
+
+func (v *View) SetContent(str string) {
+	v.writeMutex.Lock()
+	defer v.writeMutex.Unlock()
+
+	v.clear()
+	v.writeString(str)
 }
 
 // Rewind sets read and write pos to (0, 0).
@@ -802,6 +828,9 @@ func (v *View) IsTainted() bool {
 
 // draw re-draws the view's contents.
 func (v *View) draw() error {
+	v.writeMutex.Lock()
+	defer v.writeMutex.Unlock()
+
 	v.clearRunes()
 
 	if !v.Visible {