Treat oneshot systemd services as "active" when "activating"

Oneshot systemd services transition directly from activating to
dead/inactive and never show up as "active". This change treats these
services as "active" when "activating" because that's likely what the
user wants. Otherwise, backup tasks, etc. never show up as active
services in i3status-rs.

Author: Stebalien

src/blocks/service_status.rs

@@ -108,6 +108,7 @@ trait Driver {
 
 struct SystemdDriver {
     proxy: UnitProxy<'static>,
+    service_proxy: ServiceProxy<'static>,
     active_state_changed: PropertyStream<'static, String>,
 }
 
@@ -141,27 +142,49 @@ impl SystemdDriver {
         let path = format!("/org/freedesktop/systemd1/unit/{encoded_service}");
 
         let proxy = UnitProxy::builder(&dbus_conn)
-            .path(path)
+            .path(path.clone())
             .error("Could not set path")?
             .build()
             .await
             .error("Failed to create UnitProxy")?;
 
+        let service_proxy = ServiceProxy::builder(&dbus_conn)
+            .path(path)
+            .error("Could not set path")?
+            .build()
+            .await
+            .error("Failed to create ServiceProxy")?;
+
         Ok(Self {
             active_state_changed: proxy.receive_active_state_changed().await,
             proxy,
+            service_proxy,
         })
     }
 }
 
 #[async_trait]
 impl Driver for SystemdDriver {
     async fn is_active(&self) -> Result<bool> {
-        self.proxy
+        let active_state = self
+            .proxy
             .active_state()
             .await
-            .error("Could not get active_state")
-            .map(|state| state == "active")
+            .error("Could not get active_state")?;
+
+        Ok(match &*active_state {
+            "active" => true,
+            "activating" => {
+                let service_type = self
+                    .service_proxy
+                    .type_()
+                    .await
+                    .error("Could not get service type")?;
+
+                service_type == "oneshot"
+            }
+            _ => false,
+        })
     }
 
     async fn wait_for_change(&mut self) -> Result<()> {
@@ -178,3 +201,12 @@ trait Unit {
     #[zbus(property)]
     fn active_state(&self) -> zbus::Result<String>;
 }
+
+#[zbus::proxy(
+    interface = "org.freedesktop.systemd1.Service",
+    default_service = "org.freedesktop.systemd1"
+)]
+trait Service {
+    #[zbus(property, name = "Type")]
+    fn type_(&self) -> zbus::Result<String>;
+}