fix halt when player is removed

rewritten without goroutines or checking if processes exist and it seems
to work much better now.

go.mod

@@ -2,6 +2,4 @@ module github.com/hrfee/waybar-mpris
 
 go 1.15
 
-require (
-	github.com/godbus/dbus/v5 v5.0.3
-)
+require github.com/godbus/dbus/v5 v5.0.3

go.sum

@@ -1,4 +1,3 @@
 github.com/godbus/dbus v4.1.0+incompatible h1:WqqLRTsQic3apZUK9qC5sGNfXthmPXzUZ7nQPrNITa4=
-github.com/godbus/dbus v4.1.0+incompatible/go.mod h1:/YcGZj5zSblfDWMMoOzV4fas9FZnQYTkDnsGvmh2Grw=
 github.com/godbus/dbus/v5 v5.0.3 h1:ZqHaoEF7TBzh4jzPmqVhE/5A1z9of6orkAe5uHoAeME=
 github.com/godbus/dbus/v5 v5.0.3/go.mod h1:xhWf0FNVPg57R7Z0UbKHbJfkEywrmjJnf7w5xrFpKfA=

main.go

@@ -3,104 +3,221 @@ package main
 import (
 	"encoding/json"
 	"fmt"
-	"github.com/godbus/dbus/v5"
 	"sort"
 	"strings"
-	// "time"
+
+	"github.com/godbus/dbus/v5"
 )
 
-type Player struct {
-	player                           dbus.BusObject
-	playing, stopped                 bool
-	playerName, title, artist, album string
-	metadata                         map[string]dbus.Variant
-	conn                             *dbus.Conn
+var knownPlayers = map[string]string{
+	"plasma-browser-integration": "Browser",
+	"noson":                      "Noson",
 }
 
-func NewPlayer(conn *dbus.Conn, name string) *Player {
-	p := &Player{
-		player:     conn.Object(name, "/org/mpris/MediaPlayer2"),
-		conn:       conn,
-		playerName: strings.ReplaceAll(name, "org.mpris.MediaPlayer2.", ""),
+type Player struct {
+	player                               dbus.BusObject
+	fullName, name, title, artist, album string
+	playing, stopped                     bool
+	metadata                             map[string]dbus.Variant
+	conn                                 *dbus.Conn
+}
+
+const (
+	INTERFACE = "org.mpris.MediaPlayer2"
+	PATH      = "/org/mpris/MediaPlayer2"
+	PLAY      = "▶"
+	PAUSE     = ""
+	// NameOwnerChanged
+	MATCH_NOC = "type='signal',path='/org/freedesktop/DBus',interface='org.freedesktop.DBus',member='NameOwnerChanged'"
+	// PropertiesChanged
+	MATCH_PC = "type='signal',path='/org/mpris/MediaPlayer2',interface='org.freedesktop.DBus.Properties'"
+)
+
+// NewPlayer returns a new player object.
+func NewPlayer(conn *dbus.Conn, name string) (p *Player) {
+	playerName := strings.ReplaceAll(name, INTERFACE+".", "")
+	for key, val := range knownPlayers {
+		if strings.Contains(name, key) {
+			playerName = val
+			break
+		}
+	}
+	p = &Player{
+		player:   conn.Object(name, PATH),
+		conn:     conn,
+		name:     playerName,
+		fullName: name,
 	}
 	p.Refresh()
-	return p
+	return
 }
 
-func (p *Player) Refresh() {
-	val, err := p.player.GetProperty("org.mpris.MediaPlayer2.Player.PlaybackStatus")
+// Refresh grabs playback info.
+func (p *Player) Refresh() (err error) {
+	val, err := p.player.GetProperty(INTERFACE + ".Player.PlaybackStatus")
 	if err != nil {
-		panic(err)
+		p.playing = false
+		p.stopped = false
+		p.metadata = map[string]dbus.Variant{}
+		p.title = ""
+		p.artist = ""
+		p.album = ""
+		return
 	}
-	if strings.Contains(val.String(), "Playing") {
+	strVal := val.String()
+	if strings.Contains(strVal, "Playing") {
 		p.playing = true
 		p.stopped = false
-	} else if strings.Contains(val.String(), "Paused") {
+	} else if strings.Contains(strVal, "Paused") {
 		p.playing = false
 		p.stopped = false
 	} else {
 		p.playing = false
 		p.stopped = true
 	}
-	md, err := p.player.GetProperty("org.mpris.MediaPlayer2.Player.Metadata")
+	metadata, err := p.player.GetProperty(INTERFACE + ".Player.Metadata")
 	if err != nil {
+		p.metadata = map[string]dbus.Variant{}
+		p.title = ""
+		p.artist = ""
+		p.album = ""
 		return
 	}
-	p.metadata = md.Value().(map[string]dbus.Variant)
-	p.artist = strings.Join(p.metadata["xesam:artist"].Value().([]string), ", ")
-	p.title = p.metadata["xesam:title"].Value().(string)
-	p.album = p.metadata["xesam:album"].Value().(string)
+	p.metadata = metadata.Value().(map[string]dbus.Variant)
+	switch artist := p.metadata["xesam:artist"].Value().(type) {
+	case []string:
+		p.artist = strings.Join(artist, ", ")
+	case string:
+		p.artist = artist
+	default:
+		p.artist = ""
+	}
+	switch title := p.metadata["xesam:title"].Value().(type) {
+	case string:
+		p.title = title
+	default:
+		p.title = ""
+	}
+	switch album := p.metadata["xesam:album"].Value().(type) {
+	case string:
+		p.album = album
+	default:
+		p.album = ""
+	}
+	return nil
 }
 
 func (p *Player) JSON() string {
+	var items []string
+	for _, v := range []string{p.artist, p.album, p.title} {
+		if v != "" {
+			items = append(items, v)
+		}
+	}
+	if len(items) == 0 {
+		return "{}"
+	}
 	data := map[string]string{}
 	data["tooltip"] = fmt.Sprintf(
-		"%s\nby %s\nfrom %s\n(%s)",
+		"%s\nby %s\n",
 		p.title,
-		p.artist,
-		p.album,
-		p.playerName)
-	var symbol string
-	if p.playing {
-		data["class"] = "playing"
-		symbol = ""
-	} else {
-		data["class"] = "paused"
-		symbol = "▶"
+		p.artist)
+	if p.album != "" {
+		data["tooltip"] += "from " + p.album + "\n"
+	}
+	data["tooltip"] += "(" + p.name + ")"
+	symbol := PLAY
+	data["class"] = "paused"
+	if p.playing {
+		symbol = PAUSE
+		data["class"] = "playing"
+	}
+	data["text"] = symbol + " " + strings.Join(items, " - ")
+	text, err := json.Marshal(data)
+	if err != nil {
+		return "{}"
 	}
-	data["text"] = fmt.Sprintf(
-		"%s %s - %s - %s",
-		symbol,
-		p.artist,
-		p.album,
-		p.title)
-
-	text, _ := json.Marshal(data)
 	return string(text)
 }
 
-type Players []*Player
-
-func (s Players) Len() int {
-	return len(s)
+type PlayerList struct {
+	list List
+	conn *dbus.Conn
 }
 
-func (s Players) Less(i, j int) bool {
-	s[i].Refresh()
-	s[j].Refresh()
-	var states [2]int
-	if s[i].playing {
-		states[0] = 1
+type List []*Player
+
+func (ls List) Len() int {
+	return len(ls)
+}
+
+func (ls List) Less(i, j int) bool {
+	var states [2]uint8
+	for i, p := range []bool{ls[i].playing, ls[j].playing} {
+		if p {
+			states[i] = 1
+		}
 	}
-	if s[j].playing {
-		states[1] = 1
-	}
-	// reverse
+	// Reverse order
 	return states[0] > states[1]
 }
 
-func (s Players) Swap(i, j int) {
-	s[i], s[j] = s[j], s[i]
+func (ls List) Swap(i, j int) {
+	ls[i], ls[j] = ls[j], ls[i]
+}
+
+// Doesn't retain order since sorting if constantly done anyway
+func (pl *PlayerList) Remove(fullName string) {
+	var i int
+	found := false
+	for ind, p := range pl.list {
+		if p.fullName == fullName {
+			i = ind
+			found = true
+			break
+		}
+	}
+	if found {
+		pl.list[0], pl.list[i] = pl.list[i], pl.list[0]
+		pl.list = pl.list[1:]
+	}
+	// ls[len(ls)-1], ls[i] = ls[i], ls[len(ls)-1]
+	// ls = ls[:len(ls)-1]
+}
+
+func (pl *PlayerList) Reload() error {
+	var buses []string
+	err := pl.conn.BusObject().Call("org.freedesktop.DBus.ListNames", 0).Store(&buses)
+	if err != nil {
+		return err
+	}
+	for _, name := range buses {
+		if strings.HasPrefix(name, INTERFACE) {
+			pl.New(name)
+		}
+	}
+	return nil
+}
+
+func (pl *PlayerList) New(name string) {
+	pl.list = append(pl.list, NewPlayer(pl.conn, name))
+}
+
+func (pl *PlayerList) Sort() {
+	sort.Sort(pl.list)
+}
+
+func (pl *PlayerList) Refresh() {
+	for i := range pl.list {
+		pl.list[i].Refresh()
+	}
+}
+
+func (pl *PlayerList) JSON() string {
+	if len(pl.list) != 0 {
+		return pl.list[0].JSON()
+	}
+	return "{}"
 }
 
 func main() {
@@ -108,44 +225,38 @@ func main() {
 	if err != nil {
 		panic(err)
 	}
-	var players Players
-	getPlayers := func() {
-		var fd []string
-		err = conn.BusObject().Call("org.freedesktop.DBus.ListNames", 0).Store(&fd)
-		if err != nil {
-			panic(err)
-		}
-		for _, name := range fd {
-			if strings.HasPrefix(name, "org.mpris.MediaPlayer2") {
-				players = append(players, NewPlayer(conn, name))
-			}
-		}
-		sort.Sort(players)
+	players := &PlayerList{
+		conn: conn,
 	}
-	getPlayers()
-	go func() {
-		conn.BusObject().Call("org.freedesktop.DBus.AddMatch", 0,
-			"type='signal',path='/org/freedesktop/DBus',interface='org.freedesktop.DBus',member='NameOwnerChanged'")
-		c := make(chan *dbus.Signal, 10)
-		conn.Signal(c)
-		for v := range c {
-			switch name := v.Body[0].(type) {
-			case string:
-				if strings.Contains(name, "org.mpris.MediaPlayer2") && name != "org.mpris.MediaPlayer2.Player" {
-					players = append(players, NewPlayer(conn, name))
-					sort.Sort(players)
-				}
-			}
-		}
-	}()
-	conn.BusObject().Call("org.freedesktop.DBus.AddMatch", 0,
-		"type='signal',path='/org/mpris/MediaPlayer2',interface='org.freedesktop.DBus.Properties'")
+	players.Reload()
+	players.Sort()
+	fmt.Println("New array", players)
+	conn.BusObject().Call("org.freedesktop.DBus.AddMatch", 0, MATCH_NOC)
+	conn.BusObject().Call("org.freedesktop.DBus.AddMatch", 0, MATCH_PC)
 	c := make(chan *dbus.Signal, 10)
 	conn.Signal(c)
-	fmt.Println(players[0].JSON())
-	for range c {
-		sort.Sort(players)
-		players[0].Refresh()
-		fmt.Println(players[0].JSON())
+	for v := range c {
+		// fmt.Printf("SIGNAL: Sender %s, Path %s, Name %s, Body %s\n", v.Sender, v.Path, v.Name, v.Body)
+		if strings.Contains(v.Name, "NameOwnerChanged") {
+			switch name := v.Body[0].(type) {
+			case string:
+				var pid uint32
+				conn.BusObject().Call("org.freedesktop.DBus.GetConnectionUnixProcessID", 0, name).Store(&pid)
+				if strings.Contains(name, INTERFACE) {
+					if pid == 0 {
+						fmt.Println("Removing", name)
+						players.Remove(name)
+					} else {
+						fmt.Println("Adding", name)
+						players.New(name)
+					}
+				}
+			}
+		} else if strings.Contains(v.Name, "PropertiesChanged") && strings.Contains(v.Body[0].(string), INTERFACE+".Player") {
+			players.Refresh()
+			players.Sort()
+			fmt.Println(players.JSON())
+		}
+		fmt.Println("New array", players)
 	}
 }