fix: crash on startup, feat: hot reload

Signed-off-by: crecher <crecher@onyx.home>

1 files changed, 108 insertions, 0 deletions

diff --git a/restart.go b/restart.go
new file mode 100644
index 0000000..87c6c41
--- /dev/null
+++ b/restart.go
@@ -0,0 +1,108 @@
+package main
+
+import (
+	"encoding/json"
+	"log"
+	"os"
+	"strings"
+	"syscall"
+
+	"github.com/BurntSushi/xgb"
+	"github.com/BurntSushi/xgb/xproto"
+)
+
+const stateEnv = "WM_STATE"
+
+type savedClient struct {
+	Win      xproto.Window
+	Floating bool
+	Tags     BitMask
+}
+
+type savedState struct {
+	Clients    []savedClient
+	GlobalTags BitMask
+	Layout     string
+	Focused    xproto.Window
+}
+
+func restart() {
+	st := savedState{GlobalTags: GlobalTags, Layout: layout, Focused: focused}
+	for _, c := range clientList {
+		st.Clients = append(st.Clients, savedClient{c.Win, c.Floating, c.Tags})
+	}
+	data, err := json.Marshal(st)
+	if err != nil {
+		log.Println("restart: failed to save state:", err)
+		return
+	}
+
+	exe, err := os.Executable()
+	if err != nil {
+		exe = os.Args[0]
+	}
+	exe = strings.TrimSuffix(exe, " (deleted)")
+
+	env := append(os.Environ(), stateEnv+"="+string(data))
+	log.Println("restarting", exe)
+	if err := syscall.Exec(exe, os.Args, env); err != nil {
+		log.Println("restart: exec failed:", err)
+	}
+}
+
+func restoreState(conn *xgb.Conn) bool {
+	raw, ok := os.LookupEnv(stateEnv)
+	if !ok {
+		return false
+	}
+	os.Unsetenv(stateEnv)
+
+	var st savedState
+	if err := json.Unmarshal([]byte(raw), &st); err != nil {
+		log.Println("restore: bad state:", err)
+		return false
+	}
+
+	GlobalTags = st.GlobalTags
+	if st.Layout != "" {
+		layout = st.Layout
+	}
+
+	for _, sc := range st.Clients {
+		geom, err := xproto.GetGeometry(conn, xproto.Drawable(sc.Win)).Reply()
+		if err != nil {
+			continue
+		}
+		client := &Client{
+			Win:      sc.Win,
+			X:        geom.X,
+			Y:        geom.Y,
+			Width:    geom.Width,
+			Height:   geom.Height,
+			Floating: sc.Floating,
+			Tags:     sc.Tags,
+		}
+		clients[sc.Win] = client
+		clientList = append(clientList, client)
+
+		xproto.ChangeWindowAttributes(conn, sc.Win,
+			xproto.CwEventMask,
+			[]uint32{
+				xproto.EventMaskEnterWindow |
+					xproto.EventMaskFocusChange |
+					xproto.EventMaskPropertyChange,
+			})
+	}
+
+	if _, ok := clients[st.Focused]; ok {
+		focused = st.Focused
+		setInputFocus(conn, focused)
+	}
+
+	for _, c := range clients {
+		xproto.UnmapWindow(conn, c.Win)
+	}
+	updateWindows(conn)
+	drawBar(conn)
+	return true
+}