use dep

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

@@ -0,0 +1,666 @@
+// Copyright 2014 The gocui Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package gocui
+
+import (
+	"errors"
+
+	"github.com/nsf/termbox-go"
+)
+
+var (
+	// ErrQuit is used to decide if the MainLoop finished successfully.
+	ErrQuit = errors.New("quit")
+
+	// ErrUnknownView allows to assert if a View must be initialized.
+	ErrUnknownView = errors.New("unknown view")
+)
+
+// OutputMode represents the terminal's output mode (8 or 256 colors).
+type OutputMode termbox.OutputMode
+
+const (
+	// OutputNormal provides 8-colors terminal mode.
+	OutputNormal = OutputMode(termbox.OutputNormal)
+
+	// Output256 provides 256-colors terminal mode.
+	Output256 = OutputMode(termbox.Output256)
+
+	// OutputGrayScale provides greyscale terminal mode.
+	OutputGrayScale = OutputMode(termbox.OutputGrayscale)
+
+	// Output216 provides greyscale terminal mode.
+	Output216 = OutputMode(termbox.Output216)
+)
+
+// Gui represents the whole User Interface, including the views, layouts
+// and keybindings.
+type Gui struct {
+	tbEvents    chan termbox.Event
+	userEvents  chan userEvent
+	views       []*View
+	currentView *View
+	managers    []Manager
+	keybindings []*keybinding
+	maxX, maxY  int
+	outputMode  OutputMode
+
+	// BgColor and FgColor allow to configure the background and foreground
+	// colors of the GUI.
+	BgColor, FgColor Attribute
+
+	// SelBgColor and SelFgColor allow to configure the background and
+	// foreground colors of the frame of the current view.
+	SelBgColor, SelFgColor Attribute
+
+	// If Highlight is true, Sel{Bg,Fg}Colors will be used to draw the
+	// frame of the current view.
+	Highlight bool
+
+	// If Cursor is true then the cursor is enabled.
+	Cursor bool
+
+	// If Mouse is true then mouse events will be enabled.
+	Mouse bool
+
+	// If InputEsc is true, when ESC sequence is in the buffer and it doesn't
+	// match any known sequence, ESC means KeyEsc.
+	InputEsc bool
+
+	// If ASCII is true then use ASCII instead of unicode to draw the
+	// interface. Using ASCII is more portable.
+	ASCII bool
+
+	// SupportOverlaps is true when we allow for view edges to overlap with other
+	// view edges
+	SupportOverlaps bool
+}
+
+// NewGui returns a new Gui object with a given output mode.
+func NewGui(mode OutputMode, supportOverlaps bool) (*Gui, error) {
+	if err := termbox.Init(); err != nil {
+		return nil, err
+	}
+
+	g := &Gui{}
+
+	g.outputMode = mode
+	termbox.SetOutputMode(termbox.OutputMode(mode))
+
+	g.tbEvents = make(chan termbox.Event, 20)
+	g.userEvents = make(chan userEvent, 20)
+
+	g.maxX, g.maxY = termbox.Size()
+
+	g.BgColor, g.FgColor = ColorDefault, ColorDefault
+	g.SelBgColor, g.SelFgColor = ColorDefault, ColorDefault
+
+	// SupportOverlaps is true when we allow for view edges to overlap with other
+	// view edges
+	g.SupportOverlaps = supportOverlaps
+
+	return g, nil
+}
+
+// Close finalizes the library. It should be called after a successful
+// initialization and when gocui is not needed anymore.
+func (g *Gui) Close() {
+	termbox.Close()
+}
+
+// Size returns the terminal's size.
+func (g *Gui) Size() (x, y int) {
+	return g.maxX, g.maxY
+}
+
+// SetRune writes a rune at the given point, relative to the top-left
+// corner of the terminal. It checks if the position is valid and applies
+// the given colors.
+func (g *Gui) SetRune(x, y int, ch rune, fgColor, bgColor Attribute) error {
+	if x < 0 || y < 0 || x >= g.maxX || y >= g.maxY {
+		return errors.New("invalid point")
+	}
+	termbox.SetCell(x, y, ch, termbox.Attribute(fgColor), termbox.Attribute(bgColor))
+	return nil
+}
+
+// Rune returns the rune contained in the cell at the given position.
+// It checks if the position is valid.
+func (g *Gui) Rune(x, y int) (rune, error) {
+	if x < 0 || y < 0 || x >= g.maxX || y >= g.maxY {
+		return ' ', errors.New("invalid point")
+	}
+	c := termbox.CellBuffer()[y*g.maxX+x]
+	return c.Ch, nil
+}
+
+// SetView creates a new view with its top-left corner at (x0, y0)
+// and the bottom-right one at (x1, y1). If a view with the same name
+// already exists, its dimensions are updated; otherwise, the error
+// ErrUnknownView is returned, which allows to assert if the View must
+// be initialized. It checks if the position is valid.
+func (g *Gui) SetView(name string, x0, y0, x1, y1 int, overlaps byte) (*View, error) {
+	if x0 >= x1 || y0 >= y1 {
+		return nil, errors.New("invalid dimensions")
+	}
+	if name == "" {
+		return nil, errors.New("invalid name")
+	}
+
+	if v, err := g.View(name); err == nil {
+		v.x0 = x0
+		v.y0 = y0
+		v.x1 = x1
+		v.y1 = y1
+		v.tainted = true
+		return v, nil
+	}
+
+	v := newView(name, x0, y0, x1, y1, g.outputMode)
+	v.BgColor, v.FgColor = g.BgColor, g.FgColor
+	v.SelBgColor, v.SelFgColor = g.SelBgColor, g.SelFgColor
+	v.Overlaps = overlaps
+	g.views = append(g.views, v)
+	return v, ErrUnknownView
+}
+
+// SetViewOnTop sets the given view on top of the existing ones.
+func (g *Gui) SetViewOnTop(name string) (*View, error) {
+	for i, v := range g.views {
+		if v.name == name {
+			s := append(g.views[:i], g.views[i+1:]...)
+			g.views = append(s, v)
+			return v, nil
+		}
+	}
+	return nil, ErrUnknownView
+}
+
+// SetViewOnBottom sets the given view on bottom of the existing ones.
+func (g *Gui) SetViewOnBottom(name string) (*View, error) {
+	for i, v := range g.views {
+		if v.name == name {
+			s := append(g.views[:i], g.views[i+1:]...)
+			g.views = append([]*View{v}, s...)
+			return v, nil
+		}
+	}
+	return nil, ErrUnknownView
+}
+
+// Views returns all the views in the GUI.
+func (g *Gui) Views() []*View {
+	return g.views
+}
+
+// View returns a pointer to the view with the given name, or error
+// ErrUnknownView if a view with that name does not exist.
+func (g *Gui) View(name string) (*View, error) {
+	for _, v := range g.views {
+		if v.name == name {
+			return v, nil
+		}
+	}
+	return nil, ErrUnknownView
+}
+
+// ViewByPosition returns a pointer to a view matching the given position, or
+// error ErrUnknownView if a view in that position does not exist.
+func (g *Gui) ViewByPosition(x, y int) (*View, error) {
+	// traverse views in reverse order checking top views first
+	for i := len(g.views); i > 0; i-- {
+		v := g.views[i-1]
+		if x > v.x0 && x < v.x1 && y > v.y0 && y < v.y1 {
+			return v, nil
+		}
+	}
+	return nil, ErrUnknownView
+}
+
+// ViewPosition returns the coordinates of the view with the given name, or
+// error ErrUnknownView if a view with that name does not exist.
+func (g *Gui) ViewPosition(name string) (x0, y0, x1, y1 int, err error) {
+	for _, v := range g.views {
+		if v.name == name {
+			return v.x0, v.y0, v.x1, v.y1, nil
+		}
+	}
+	return 0, 0, 0, 0, ErrUnknownView
+}
+
+// DeleteView deletes a view by name.
+func (g *Gui) DeleteView(name string) error {
+	for i, v := range g.views {
+		if v.name == name {
+			g.views = append(g.views[:i], g.views[i+1:]...)
+			return nil
+		}
+	}
+	return ErrUnknownView
+}
+
+// SetCurrentView gives the focus to a given view.
+func (g *Gui) SetCurrentView(name string) (*View, error) {
+	for _, v := range g.views {
+		if v.name == name {
+			g.currentView = v
+			return v, nil
+		}
+	}
+	return nil, ErrUnknownView
+}
+
+// CurrentView returns the currently focused view, or nil if no view
+// owns the focus.
+func (g *Gui) CurrentView() *View {
+	return g.currentView
+}
+
+// SetKeybinding creates a new keybinding. If viewname equals to ""
+// (empty string) then the keybinding will apply to all views. key must
+// be a rune or a Key.
+func (g *Gui) SetKeybinding(viewname string, key interface{}, mod Modifier, handler func(*Gui, *View) error) error {
+	var kb *keybinding
+
+	k, ch, err := getKey(key)
+	if err != nil {
+		return err
+	}
+	kb = newKeybinding(viewname, k, ch, mod, handler)
+	g.keybindings = append(g.keybindings, kb)
+	return nil
+}
+
+// DeleteKeybinding deletes a keybinding.
+func (g *Gui) DeleteKeybinding(viewname string, key interface{}, mod Modifier) error {
+	k, ch, err := getKey(key)
+	if err != nil {
+		return err
+	}
+
+	for i, kb := range g.keybindings {
+		if kb.viewName == viewname && kb.ch == ch && kb.key == k && kb.mod == mod {
+			g.keybindings = append(g.keybindings[:i], g.keybindings[i+1:]...)
+			return nil
+		}
+	}
+	return errors.New("keybinding not found")
+}
+
+// DeleteKeybindings deletes all keybindings of view.
+func (g *Gui) DeleteKeybindings(viewname string) {
+	var s []*keybinding
+	for _, kb := range g.keybindings {
+		if kb.viewName != viewname {
+			s = append(s, kb)
+		}
+	}
+	g.keybindings = s
+}
+
+// getKey takes an empty interface with a key and returns the corresponding
+// typed Key or rune.
+func getKey(key interface{}) (Key, rune, error) {
+	switch t := key.(type) {
+	case Key:
+		return t, 0, nil
+	case rune:
+		return 0, t, nil
+	default:
+		return 0, 0, errors.New("unknown type")
+	}
+}
+
+// userEvent represents an event triggered by the user.
+type userEvent struct {
+	f func(*Gui) error
+}
+
+// Update executes the passed function. This method can be called safely from a
+// goroutine in order to update the GUI. It is important to note that the
+// passed function won't be executed immediately, instead it will be added to
+// the user events queue. Given that Update spawns a goroutine, the order in
+// which the user events will be handled is not guaranteed.
+func (g *Gui) Update(f func(*Gui) error) {
+	go func() { g.userEvents <- userEvent{f: f} }()
+}
+
+// A Manager is in charge of GUI's layout and can be used to build widgets.
+type Manager interface {
+	// Layout is called every time the GUI is redrawn, it must contain the
+	// base views and its initializations.
+	Layout(*Gui) error
+}
+
+// The ManagerFunc type is an adapter to allow the use of ordinary functions as
+// Managers. If f is a function with the appropriate signature, ManagerFunc(f)
+// is an Manager object that calls f.
+type ManagerFunc func(*Gui) error
+
+// Layout calls f(g)
+func (f ManagerFunc) Layout(g *Gui) error {
+	return f(g)
+}
+
+// SetManager sets the given GUI managers. It deletes all views and
+// keybindings.
+func (g *Gui) SetManager(managers ...Manager) {
+	g.managers = managers
+	g.currentView = nil
+	g.views = nil
+	g.keybindings = nil
+
+	go func() { g.tbEvents <- termbox.Event{Type: termbox.EventResize} }()
+}
+
+// SetManagerFunc sets the given manager function. It deletes all views and
+// keybindings.
+func (g *Gui) SetManagerFunc(manager func(*Gui) error) {
+	g.SetManager(ManagerFunc(manager))
+}
+
+// MainLoop runs the main loop until an error is returned. A successful
+// finish should return ErrQuit.
+func (g *Gui) MainLoop() error {
+	go func() {
+		for {
+			g.tbEvents <- termbox.PollEvent()
+		}
+	}()
+
+	inputMode := termbox.InputAlt
+	if true { // previously g.InputEsc, but didn't seem to work
+		inputMode = termbox.InputEsc
+	}
+	if g.Mouse {
+		inputMode |= termbox.InputMouse
+	}
+	termbox.SetInputMode(inputMode)
+
+	if err := g.flush(); err != nil {
+		return err
+	}
+	for {
+		select {
+		case ev := <-g.tbEvents:
+			if err := g.handleEvent(&ev); err != nil {
+				return err
+			}
+		case ev := <-g.userEvents:
+			if err := ev.f(g); err != nil {
+				return err
+			}
+		}
+		if err := g.consumeevents(); err != nil {
+			return err
+		}
+		if err := g.flush(); err != nil {
+			return err
+		}
+	}
+}
+
+// consumeevents handles the remaining events in the events pool.
+func (g *Gui) consumeevents() error {
+	for {
+		select {
+		case ev := <-g.tbEvents:
+			if err := g.handleEvent(&ev); err != nil {
+				return err
+			}
+		case ev := <-g.userEvents:
+			if err := ev.f(g); err != nil {
+				return err
+			}
+		default:
+			return nil
+		}
+	}
+}
+
+// handleEvent handles an event, based on its type (key-press, error,
+// etc.)
+func (g *Gui) handleEvent(ev *termbox.Event) error {
+	switch ev.Type {
+	case termbox.EventKey, termbox.EventMouse:
+		return g.onKey(ev)
+	case termbox.EventError:
+		return ev.Err
+	default:
+		return nil
+	}
+}
+
+// flush updates the gui, re-drawing frames and buffers.
+func (g *Gui) flush() error {
+	termbox.Clear(termbox.Attribute(g.FgColor), termbox.Attribute(g.BgColor))
+
+	maxX, maxY := termbox.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.tainted = true
+		}
+	}
+	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.Frame {
+			var fgColor, bgColor Attribute
+			if g.Highlight && v == g.currentView {
+				fgColor = g.SelFgColor
+				bgColor = g.SelBgColor
+			} else {
+				fgColor = g.FgColor
+				bgColor = g.BgColor
+			}
+
+			if err := g.drawFrameEdges(v, fgColor, bgColor); err != nil {
+				return err
+			}
+			if err := g.drawFrameCorners(v, fgColor, bgColor); err != nil {
+				return err
+			}
+			if v.Title != "" {
+				if err := g.drawTitle(v, fgColor, bgColor); err != nil {
+					return err
+				}
+			}
+		}
+		if err := g.draw(v); err != nil {
+			return err
+		}
+	}
+	termbox.Flush()
+	return nil
+}
+
+// drawFrameEdges draws the horizontal and vertical edges of a view.
+func (g *Gui) drawFrameEdges(v *View, fgColor, bgColor Attribute) error {
+	runeH, runeV := '─', '│'
+	if g.ASCII {
+		runeH, runeV = '-', '|'
+	}
+
+	for x := v.x0 + 1; x < v.x1 && x < g.maxX; x++ {
+		if x < 0 {
+			continue
+		}
+		if v.y0 > -1 && v.y0 < g.maxY {
+			if err := g.SetRune(x, v.y0, runeH, fgColor, bgColor); err != nil {
+				return err
+			}
+		}
+		if v.y1 > -1 && v.y1 < g.maxY {
+			if err := g.SetRune(x, v.y1, runeH, fgColor, bgColor); err != nil {
+				return err
+			}
+		}
+	}
+	for y := v.y0 + 1; y < v.y1 && y < g.maxY; y++ {
+		if y < 0 {
+			continue
+		}
+		if v.x0 > -1 && v.x0 < g.maxX {
+			if err := g.SetRune(v.x0, y, runeV, fgColor, bgColor); err != nil {
+				return err
+			}
+		}
+		if v.x1 > -1 && v.x1 < g.maxX {
+			if err := g.SetRune(v.x1, y, runeV, fgColor, bgColor); err != nil {
+				return err
+			}
+		}
+	}
+	return nil
+}
+
+func cornerRune(index byte) rune {
+	return []rune{' ', '│', '│', '│', '─', '┘', '┐', '┤', '─', '└', '┌', '├', '├', '┴', '┬', '┼'}[index]
+}
+
+func corner(v *View, directions byte) rune {
+	index := v.Overlaps | directions
+	return cornerRune(index)
+}
+
+// drawFrameCorners draws the corners of the view.
+func (g *Gui) drawFrameCorners(v *View, fgColor, bgColor Attribute) error {
+	runeTL, runeTR, runeBL, runeBR := '┌', '┐', '└', '┘'
+	if g.SupportOverlaps {
+		runeTL = corner(v, BOTTOM|RIGHT)
+		runeTR = corner(v, BOTTOM|LEFT)
+		runeBL = corner(v, TOP|RIGHT)
+		runeBR = corner(v, TOP|LEFT)
+	}
+	if g.ASCII {
+		runeTL, runeTR, runeBL, runeBR = '+', '+', '+', '+'
+	}
+
+	corners := []struct {
+		x, y int
+		ch   rune
+	}{{v.x0, v.y0, runeTL}, {v.x1, v.y0, runeTR}, {v.x0, v.y1, runeBL}, {v.x1, v.y1, runeBR}}
+
+	for _, c := range corners {
+		if c.x >= 0 && c.y >= 0 && c.x < g.maxX && c.y < g.maxY {
+			if err := g.SetRune(c.x, c.y, c.ch, fgColor, bgColor); err != nil {
+				return err
+			}
+		}
+	}
+	return nil
+}
+
+// drawTitle draws the title of the view.
+func (g *Gui) drawTitle(v *View, fgColor, bgColor Attribute) error {
+	if v.y0 < 0 || v.y0 >= g.maxY {
+		return nil
+	}
+
+	for i, ch := range v.Title {
+		x := v.x0 + i + 2
+		if x < 0 {
+			continue
+		} else if x > v.x1-2 || x >= g.maxX {
+			break
+		}
+		if err := g.SetRune(x, v.y0, ch, fgColor, bgColor); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+// draw manages the cursor and calls the draw function of a view.
+func (g *Gui) draw(v *View) error {
+	if g.Cursor {
+		if curview := g.currentView; curview != nil {
+			vMaxX, vMaxY := curview.Size()
+			if curview.cx < 0 {
+				curview.cx = 0
+			} else if curview.cx >= vMaxX {
+				curview.cx = vMaxX - 1
+			}
+			if curview.cy < 0 {
+				curview.cy = 0
+			} else if curview.cy >= vMaxY {
+				curview.cy = vMaxY - 1
+			}
+
+			gMaxX, gMaxY := g.Size()
+			cx, cy := curview.x0+curview.cx+1, curview.y0+curview.cy+1
+			if cx >= 0 && cx < gMaxX && cy >= 0 && cy < gMaxY {
+				termbox.SetCursor(cx, cy)
+			} else {
+				termbox.HideCursor()
+			}
+		}
+	} else {
+		termbox.HideCursor()
+	}
+
+	v.clearRunes()
+	if err := v.draw(); err != nil {
+		return err
+	}
+	return nil
+}
+
+// onKey manages key-press events. A keybinding handler is called when
+// a key-press or mouse event satisfies a configured keybinding. Furthermore,
+// currentView's internal buffer is modified if currentView.Editable is true.
+func (g *Gui) onKey(ev *termbox.Event) error {
+	switch ev.Type {
+	case termbox.EventKey:
+		matched, err := g.execKeybindings(g.currentView, ev)
+		if err != nil {
+			return err
+		}
+		if matched {
+			break
+		}
+		if g.currentView != nil && g.currentView.Editable && g.currentView.Editor != nil {
+			g.currentView.Editor.Edit(g.currentView, Key(ev.Key), ev.Ch, Modifier(ev.Mod))
+		}
+	case termbox.EventMouse:
+		mx, my := ev.MouseX, ev.MouseY
+		v, err := g.ViewByPosition(mx, my)
+		if err != nil {
+			break
+		}
+		if err := v.SetCursor(mx-v.x0-1, my-v.y0-1); err != nil {
+			return err
+		}
+		if _, err := g.execKeybindings(v, ev); err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
+
+// execKeybindings executes the keybinding handlers that match the passed view
+// and event. The value of matched is true if there is a match and no errors.
+func (g *Gui) execKeybindings(v *View, ev *termbox.Event) (matched bool, err error) {
+	matched = false
+	for _, kb := range g.keybindings {
+		if kb.handler == nil {
+			continue
+		}
+		if kb.matchKeypress(Key(ev.Key), ev.Ch, Modifier(ev.Mod)) && kb.matchView(v) {
+			if err := kb.handler(g, v); err != nil {
+				return false, err
+			}
+			matched = true
+		}
+	}
+	return matched, nil
+}