final: refactor for removal of system package and reduction of interactions to state package

State query command has been moved to main where it belongs, "system" information are now fetched in app.New and stored in *App with accessors for relevant values. Exit (cleanup-related) functions are separated into its dedicated "final" package.

Signed-off-by: Ophestra Umiker <cat@ophivana.moe>

internal/state/data.go

@@ -0,0 +1,51 @@
+package state
+
+import (
+	"encoding/gob"
+	"os"
+	"path"
+)
+
+// we unfortunately have to assume there are never races between processes
+// this and launcher should eventually be replaced by a server process
+
+type launcherState struct {
+	PID        int
+	Launcher   string
+	Argv       []string
+	Command    []string
+	Capability Enablements
+}
+
+func ReadLaunchers(runDirPath, uid string) ([]*launcherState, error) {
+	var f *os.File
+	var r []*launcherState
+	launcherPrefix := path.Join(runDirPath, uid)
+
+	if pl, err := os.ReadDir(launcherPrefix); err != nil {
+		return nil, err
+	} else {
+		for _, e := range pl {
+			if err = func() error {
+				if f, err = os.Open(path.Join(launcherPrefix, e.Name())); err != nil {
+					return err
+				} else {
+					defer func() {
+						if f.Close() != nil {
+							// unreachable
+							panic("foreign state file closed prematurely")
+						}
+					}()
+
+					var s launcherState
+					r = append(r, &s)
+					return gob.NewDecoder(f).Decode(&s)
+				}
+			}(); err != nil {
+				return nil, err
+			}
+		}
+	}
+
+	return r, nil
+}