Merge branch 'citreae535-change_delete'

examples/uninstall_service.rs

@@ -1,25 +1,50 @@
 #[cfg(windows)]
 fn main() -> windows_service::Result<()> {
-    use std::{thread, time::Duration};
+    use std::{
+        thread::sleep,
+        time::{Duration, Instant},
+    };
+
     use windows_service::{
         service::{ServiceAccess, ServiceState},
         service_manager::{ServiceManager, ServiceManagerAccess},
     };
+    use windows_sys::Win32::Foundation::ERROR_SERVICE_DOES_NOT_EXIST;
 
     let manager_access = ServiceManagerAccess::CONNECT;
     let service_manager = ServiceManager::local_computer(None::<&str>, manager_access)?;
 
     let service_access = ServiceAccess::QUERY_STATUS | ServiceAccess::STOP | ServiceAccess::DELETE;
     let service = service_manager.open_service("ping_service", service_access)?;
 
-    let service_status = service.query_status()?;
-    if service_status.current_state != ServiceState::Stopped {
+    // The service will be marked for deletion as long as this function call succeeds.
+    // However, it will not be deleted from the database until it is stopped and all open handles to it are closed.
+    service.delete()?;
+    // Our handle to it is not closed yet. So we can still query it.
+    if service.query_status()?.current_state != ServiceState::Stopped {
+        // If the service cannot be stopped, it will be deleted when the system restarts.
         service.stop()?;
-        // Wait for service to stop
-        thread::sleep(Duration::from_secs(1));
     }
+    // Explicitly close our open handle to the service. This is automatically called when `service` goes out of scope.
+    drop(service);
+
+    // Win32 API does not give us a way to wait for service deletion.
+    // To check if the service is deleted from the database, we have to poll it ourselves.
+    let start = Instant::now();
+    let timeout = Duration::from_secs(5);
+    while start.elapsed() < timeout {
+        if let Err(windows_service::Error::Winapi(e)) =
+            service_manager.open_service("ping_service", ServiceAccess::QUERY_STATUS)
+        {
+            if e.raw_os_error() == Some(ERROR_SERVICE_DOES_NOT_EXIST as i32) {
+                println!("ping_service is deleted.");
+                return Ok(());
+            }
+        }
+        sleep(Duration::from_secs(1));
+    }
+    println!("ping_service is marked for deletion.");
 
-    service.delete()?;
     Ok(())
 }
 

src/service.rs

@@ -1455,8 +1455,13 @@ impl Service {
         }
     }
 
-    /// Delete the service from system registry.
-    pub fn delete(self) -> crate::Result<()> {
+    /// Mark the service for deletion from the service control manager database.
+    ///
+    /// The database entry is not removed until all open handles to the service have been closed
+    /// and the service is stopped. If the service is not or cannot be stopped, the database entry
+    /// is removed when the system is restarted. This function will return an error if the service
+    /// has already been marked for deletion.
+    pub fn delete(&self) -> crate::Result<()> {
         let success = unsafe { Services::DeleteService(self.service_handle.raw_handle()) };
         if success == 0 {
             Err(Error::Winapi(io::Error::last_os_error()))