Implement tree kill for Windows

desktop/src-tauri/process/src/process_manager.rs

@@ -125,7 +125,7 @@ impl ProcessManager<'_> {
         match self.processes.get_mut(&game_id) {
             Some(process) => {
                 process.manually_killed = true;
-                process.handle.kill()?;
+                kill_process_tree(&process.handle)?;
                 let exit_status = process.handle.wait()?;
                 info!("exit status: {:?}", exit_status);
                 Ok(())
@@ -593,6 +593,30 @@ impl ProcessManager<'_> {
     }
 }
 
+fn kill_process_tree(handle: &SharedChild) -> io::Result<()> {
+    #[cfg(target_os = "windows")]
+    {
+        // handle.kill() only terminates the launched process (often a cmd or
+        // powershell wrapper), orphaning the actual game. taskkill /T kills the
+        // whole process tree.
+        use std::os::windows::process::CommandExt;
+        const CREATE_NO_WINDOW: u32 = 0x08000000;
+        let pid = handle.id().to_string();
+        let killed = Command::new("taskkill")
+            .args(["/F", "/T", "/PID", pid.as_str()])
+            .creation_flags(CREATE_NO_WINDOW)
+            .stdout(std::process::Stdio::null())
+            .stderr(std::process::Stdio::null())
+            .status()
+            .map(|status| status.success())
+            .unwrap_or(false);
+        if killed {
+            return Ok(());
+        }
+    }
+    handle.kill()
+}
+
 pub trait ProcessHandler: Send + 'static {
     fn create_launch_process(
         &self,