settings: Let ReadOne fall back to Read on error

settings/read.go

@@ -0,0 +1,59 @@
+package settings
+
+import (
+	"github.com/godbus/dbus/v5"
+	"github.com/rymdport/portal/internal/apis"
+)
+
+const (
+	readCallPath    = settingsCallPath + ".Read"
+	readOneCallPath = settingsCallPath + ".ReadOne"
+	readAllCallPath = settingsCallPath + ".ReadAll"
+)
+
+// ReadAll returns all values for the corresponding namespaces passed.
+// If namespaces is an empty array or contains an empty string it matches all.
+// Globbing is supported but only for trailing sections, e.g. “org.example.*”.
+func ReadAll(namespaces []string) (map[string](map[string]dbus.Variant), error) {
+	conn, err := dbus.SessionBus() // Shared connection, don't close.
+	if err != nil {
+		return nil, err
+	}
+
+	obj := conn.Object(apis.ObjectName, apis.ObjectPath)
+	call := obj.Call(readAllCallPath, 0, namespaces)
+	if call.Err != nil {
+		return nil, call.Err
+	}
+
+	var value map[string](map[string]dbus.Variant)
+	err = call.Store(&value)
+	return value, err
+}
+
+// ReadOne reads a single value which may be any valid DBus type. Returns an error on any unknown namespace or key.
+func ReadOne(namespace, key string) (any, error) {
+	value, err := read(readOneCallPath, namespace, key)
+	if err != nil {
+		return read(readCallPath, namespace, key) // Use deprecated fallback if new interface does not exist.
+	}
+
+	return value, err
+}
+
+func read(callPath, namespace, key string) (any, error) {
+	conn, err := dbus.SessionBus() // Shared connection, don't close.
+	if err != nil {
+		return nil, err
+	}
+
+	obj := conn.Object(apis.ObjectName, apis.ObjectPath)
+	call := obj.Call(callPath, 0, namespace, key)
+	if call.Err != nil {
+		return nil, call.Err
+	}
+
+	var value any
+	err = call.Store(&value)
+	return value, err
+}