Add variable-period block refreshes

Signed-off-by: AKP <tom@tdpain.net>

cmd/bar/main.go

@@ -33,7 +33,7 @@ func main() {
 }
 
 func run() error {
-	b := i3bar.New(os.Stdout, os.Stdin, time.Second*2, syscall.SIGUSR1)
+	b := i3bar.New(os.Stdout, os.Stdin, syscall.SIGUSR1)
 	if err := b.Initialise(); err != nil {
 		return err
 	}
@@ -57,8 +57,8 @@ func run() error {
 		providers.NewAudioPlayer(32),
 	)
 
-	if err := b.Emit([]i3bar.BlockGenerator{
-		providers.NewPlainText("cdmbar" + commitHash),
+	if err := b.Emit([]*i3bar.Block{
+		{FullText: "cdmbar" + commitHash},
 	}); err != nil {
 		return err
 	}

internal/i3bar/i3bar.go

@@ -14,23 +14,25 @@ import (
 	"github.com/rs/zerolog/log"
 )
 
-type I3bar struct {
-	writer               io.Writer
-	reader               io.Reader
-	updateInterval       time.Duration
-	updateSignal         syscall.Signal
-	registeredGenerators []BlockGenerator
-	registeredConsumers  []ClickEventConsumer
-
-	hasInitialised   bool
-	hasSentFirstLine bool
+type generatorInfo struct {
+	Provider         BlockGenerator
+	HasClickConsumer bool
+	Last      *Block
 }
 
-func New(writer io.Writer, reader io.Reader, updateInterval time.Duration, updateSignal syscall.Signal) *I3bar {
+type I3bar struct {
+	writer         io.Writer
+	reader         io.Reader
+	updateSignal   syscall.Signal
+
+	generators []*generatorInfo
+	tickNumber uint8
+}
+
+func New(writer io.Writer, reader io.Reader, updateSignal syscall.Signal) *I3bar {
 	return &I3bar{
 		writer:         writer,
 		reader:         reader,
-		updateInterval: updateInterval,
 		updateSignal:   updateSignal,
 	}
 }
@@ -44,11 +46,10 @@ func (b *I3bar) Initialise() error {
 		return err
 	}
 
-	if _, err := b.writer.Write(append(capabilities, '\n')); err != nil {
+	if _, err := b.writer.Write(append(capabilities, []byte("\n[\n")...)); err != nil {
 		return err
 	}
 
-	b.hasInitialised = true
 	return nil
 }
 
@@ -59,42 +60,13 @@ var defaultColorSet = &ColorSet{
 	Background: &Color{0x28, 0x28, 0x28},
 }
 
-func (b *I3bar) Emit(generators []BlockGenerator) error {
-	if !b.hasInitialised {
-		if err := b.Initialise(); err != nil {
-			return err
-		}
-	}
-
-	var blocks []*Block
-	for _, generator := range generators {
-		b, err := generator.Block(defaultColorSet)
-		if err != nil {
-			log.Error().Err(err).Str("generator", fmt.Sprintf("%T", generator)).Send()
-			b = &Block{
-				FullText:  "ERROR",
-				TextColor: defaultColorSet.Bad,
-			}
-		}
-		if b == nil {
-			continue
-		}
-		blocks = append(blocks, b)
-	}
-
+func (b *I3bar) Emit(blocks []*Block) error {
 	jsonData, err := json.Marshal(blocks)
 	if err != nil {
 		return err
 	}
 
-	if !b.hasSentFirstLine {
-		jsonData = append([]byte("[\n"), jsonData...)
-		b.hasSentFirstLine = true
-	} else {
-		jsonData = append([]byte{','}, jsonData...)
-	}
-
-	jsonData = append(jsonData, '\n')
+	jsonData = append(jsonData, []byte(",\n")...)
 
 	if _, err := b.writer.Write(jsonData); err != nil {
 		return err
@@ -107,24 +79,25 @@ func (b *I3bar) Emit(generators []BlockGenerator) error {
 // function should not be called after StartLoop is called.
 func (b *I3bar) RegisterBlockGenerator(bg ...BlockGenerator) {
 	for _, bgx := range bg {
-		b.registeredGenerators = append([]BlockGenerator{bgx}, b.registeredGenerators...)
-	}
+		_, hasClickConsumer := bgx.(ClickEventConsumer)
 
-	for _, generator := range bg {
-		if g, ok := generator.(ClickEventConsumer); ok {
-			b.registeredConsumers = append(b.registeredConsumers, g)
-		}
+		metadata := new(generatorInfo)
+		metadata.Provider = bgx
+		metadata.HasClickConsumer = hasClickConsumer
+
+		b.generators = append([]*generatorInfo{metadata}, b.generators...)
 	}
 }
 
 func (b *I3bar) StartLoop() error {
+
 	// The ticker will start after the specified duration, not when we
 	// instantiate it. Circumventing that here by calling Emit now.
-	if err := b.Emit(b.registeredGenerators); err != nil {
+	if err := b.tick(false); err != nil {
 		return err
 	}
 
-	ticker := time.NewTicker(b.updateInterval)
+	ticker := time.NewTicker(time.Second)
 	sigUpdate := make(chan os.Signal, 1)
 	signal.Notify(sigUpdate, os.Signal(b.updateSignal))
 
@@ -135,17 +108,58 @@ func (b *I3bar) StartLoop() error {
 	for {
 		select {
 		case <-sigUpdate:
-			if err := b.Emit(b.registeredGenerators); err != nil {
-				log.Error().Err(err).Msg("could not emit registered generators")
+			if err := b.tick(true); err != nil {
+				log.Error().Err(err).Msg("could not tick")
 			}
 		case <-ticker.C:
-			if err := b.Emit(b.registeredGenerators); err != nil {
-				log.Error().Err(err).Msg("could not emit registered generators")
+			if err := b.tick(false); err != nil {
+				log.Error().Err(err).Msg("could not tick")
 			}
 		}
 	}
 }
 
+func (b *I3bar) tick(override bool) error {
+	var hasChanged bool
+	for _, gen := range b.generators {
+		if override || (gen.Provider.Frequency() == 0 && gen.Last == nil) || (gen.Provider.Frequency() != 0 && b.tickNumber%gen.Provider.Frequency() == 0) {
+			block, err := gen.Provider.Block(defaultColorSet)
+			if err != nil {
+				log.Error().Err(err).Str("generator", fmt.Sprintf("%T", gen.Provider)).Send()
+				block = &Block{
+					FullText:  "ERROR",
+					TextColor: defaultColorSet.Bad,
+				}
+			}
+			if block == nil {
+				block = &Block{
+					FullText:  "MISSING",
+					TextColor: defaultColorSet.Warning,
+				}
+			}
+
+			if block != gen.Last {
+				gen.Last = block
+				hasChanged = true
+			}
+		}
+	}
+
+	if hasChanged {
+		var blocks []*Block
+		for _, gen := range b.generators {
+			blocks = append(blocks, gen.Last)
+		}
+		if err := b.Emit(blocks); err != nil {
+			return err
+		}
+	}
+
+	b.tickNumber += 1
+
+	return nil
+}
+
 func (b *I3bar) consumerLoop(requestBarRefresh func()) {
 	r := bufio.NewReader(b.reader)
 	for {
@@ -166,10 +180,13 @@ func (b *I3bar) consumerLoop(requestBarRefresh func()) {
 			continue // idk what this could be but it's not relevant so BYE!
 		}
 
-		for _, consumer := range b.registeredConsumers {
-			consumerName, consumerInstance := consumer.GetNameAndInstance()
+		for _, consumer := range b.generators {
+			if !consumer.HasClickConsumer {
+				continue
+			}
+			consumerName, consumerInstance := consumer.Provider.GetNameAndInstance()
 			if consumerName == event.Name && (consumerName == "" || consumerInstance == event.Instance) {
-				if consumer.OnClick(event) {
+				if consumer.Provider.(ClickEventConsumer).OnClick(event) {
 					requestBarRefresh()
 				}
 			}
@@ -204,6 +221,9 @@ type ProvidesNameAndInstance interface {
 type BlockGenerator interface {
 	ProvidesNameAndInstance
 	Block(*ColorSet) (*Block, error)
+	// Frequency should return the frequency at which the block is updated, as
+	// "1 per n seconds".
+	Frequency() uint8
 }
 
 type ClickEvent struct {

internal/providers/audioPlayer.go

@@ -38,6 +38,10 @@ func NewAudioPlayer(maxLabelLength int) *AudioPlayer {
 	}
 }
 
+func (g *AudioPlayer) Frequency() uint8 {
+	return 1
+}
+
 type playingAudioInfo struct {
 	Track  string
 	Artist string

internal/providers/battery.go

@@ -27,6 +27,7 @@ type Battery struct {
 
 	name                         string
 	previousWasBackgroundWarning bool
+	isAlert                      bool
 }
 
 func NewBattery(deviceName string, fullThreshold, okThreshold, warningThreshold float32) i3bar.BlockGenerator {
@@ -35,10 +36,17 @@ func NewBattery(deviceName string, fullThreshold, okThreshold, warningThreshold
 		FullThreshold:    fullThreshold,
 		OkThreshold:      okThreshold,
 		WarningThreshold: warningThreshold,
-		name: "battery",
+		name:             "battery",
 	}
 }
 
+func (g *Battery) Frequency() uint8 {
+	if g.isAlert {
+		return 1
+	}
+	return 5
+}
+
 func (g *Battery) infoPath() string {
 	return path.Join("/sys/class/power_supply", g.DeviceName)
 }
@@ -124,6 +132,8 @@ func (g *Battery) Block(colors *i3bar.ColorSet) (*i3bar.Block, error) {
 
 	if percentage < g.WarningThreshold && g.WarningThreshold != 0 {
 
+		g.isAlert = true
+
 		if g.previousWasBackgroundWarning || state == batteryStateCharging { // disable flashing when on charge
 			block.TextColor = colors.Bad
 		} else {
@@ -134,6 +144,8 @@ func (g *Battery) Block(colors *i3bar.ColorSet) (*i3bar.Block, error) {
 
 	} else if percentage < g.OkThreshold && g.OkThreshold != 0 {
 		block.TextColor = colors.Warning
+	} else {
+		g.isAlert = false
 	}
 
 	switch state {

internal/providers/cpu.go

@@ -30,6 +30,10 @@ func NewCPU(okThreshold, warningThreshold float32) i3bar.BlockGenerator {
 	return m
 }
 
+func (g *CPU) Frequency() uint8 {
+	return 2
+}
+
 func (g *CPU) doSample() error {
 	contents, err := ioutil.ReadFile("/proc/stat")
 	if err != nil {

internal/providers/datetime.go

@@ -17,6 +17,10 @@ func NewDateTime() i3bar.BlockGenerator {
 	}
 }
 
+func (g *DateTime) Frequency() uint8 {
+	return 1
+}
+
 func (g *DateTime) Block(*i3bar.ColorSet) (*i3bar.Block, error) {
 	cTime := time.Now().Local()
 

internal/providers/disk.go

@@ -27,6 +27,10 @@ func NewDisk(mountPath string, okThreshold, warningThreshold float32) i3bar.Bloc
 	}
 }
 
+func (g *Disk) Frequency() uint8 {
+	return 5
+}
+
 func (g *Disk) getAvailable() (float32, error) {
 	cmdout, err := runCommand("df", "-x", "fuse.portal")
 	if err != nil {

internal/providers/ipAddr.go

@@ -21,6 +21,10 @@ func NewIPAddress(adapter string) i3bar.BlockGenerator {
 	}
 }
 
+func (g *IPAddress) Frequency() uint8 {
+	return 5
+}
+
 func (g *IPAddress) getAdapterIPAddress() (string, error) {
 	// call ifconfig
 	output, err := runCommand("ifconfig")

internal/providers/launchProgram.go

@@ -21,6 +21,10 @@ func NewLaunchProgram(text string, executable string) i3bar.BlockGenerator {
 	}
 }
 
+func (g *LaunchProgram) Frequency() uint8 {
+	return 255
+}
+
 func (g *LaunchProgram) Block(*i3bar.ColorSet) (*i3bar.Block, error) {
 	return &i3bar.Block{
 		Name:     g.name,

internal/providers/memory.go

@@ -25,6 +25,10 @@ func NewMemory(okThreshold, warningThreshold float32) i3bar.BlockGenerator {
 	}
 }
 
+func (g *Memory) Frequency() uint8 {
+	return 2
+}
+
 var (
 	memoryTotalRegexp     = regexp.MustCompile(`MemTotal: +(\d+) kB`)
 	memoryAvailableRegexp = regexp.MustCompile(`MemAvailable: +(\d+) kB`)

internal/providers/plainText.go

@@ -15,6 +15,10 @@ func NewPlainText(text string) i3bar.BlockGenerator {
 	}
 }
 
+func (g *PlainText) Frequency() uint8 {
+	return 255
+}
+
 func (g *PlainText) Block(*i3bar.ColorSet) (*i3bar.Block, error) {
 	return &i3bar.Block{
 		Name:     g.name,

internal/providers/pulseaudioVolume.go

@@ -25,6 +25,10 @@ func NewPulseaudioVolume() i3bar.BlockGenerator {
 	}
 }
 
+func (g *PulseaudioVolume) Frequency() uint8 {
+	return 2
+}
+
 func (g *PulseaudioVolume) getInfo() (string, error) {
 	x, err := runCommand("pacmd", "info")
 	return string(x), err

internal/providers/timer.go

@@ -28,6 +28,10 @@ func NewTimer(useShortLabel bool) i3bar.BlockGenerator {
 	}
 }
 
+func (g *Timer) Frequency() uint8 {
+	return 1
+}
+
 func (g *Timer) OnClick(event *i3bar.ClickEvent) bool {
 	resetButtonPressed := event.Button == i3bar.RightMouseButton
 	triggerButtonPressed := event.Button == i3bar.LeftMouseButton

internal/providers/wifi.go

@@ -26,6 +26,10 @@ func NewWiFi(adapter string, okThreshold float32) i3bar.BlockGenerator {
 	}
 }
 
+func (g *WiFi) Frequency() uint8 {
+	return 5
+}
+
 var (
 	// For use with iwconfig
 	essidRegexp       = regexp.MustCompile(`ESSID:(?:"(.+)"|off/any)`)