lua: subprocess: cancel pending I/O before return

I'm not sure if this is necessary, but it can't hurt, and it's what
you're supposed to do before leaving the stack frame that contains the
OVERLAPPED object and the buffer. If there is no pending I/O, CancelIo
will do nothing and GetOverlappedResult will silently fail.

1 files changed, 7 insertions, 2 deletions

diff --git a/player/lua.c b/player/lua.c
index 8a2e3ec925..f46094f79c 100644
--- a/player/lua.c
+++ b/player/lua.c
@@ -1422,9 +1422,14 @@ static int subprocess(char **args, struct mp_cancel *cancel, void *ctx,
 
 done:
     for (int i = 0; i < 2; i++) {
-        if (pipes[i].ol.hEvent) CloseHandle(pipes[i].ol.hEvent);
-        if (pipes[i].read) CloseHandle(pipes[i].read);
+        if (pipes[i].read) {
+            // Cancel any pending I/O (if the process was killed)
+            CancelIo(pipes[i].read);
+            GetOverlappedResult(pipes[i].read, &pipes[i].ol, &r, TRUE);
+            CloseHandle(pipes[i].read);
+        }
         if (pipes[i].write) CloseHandle(pipes[i].write);
+        if (pipes[i].ol.hEvent) CloseHandle(pipes[i].ol.hEvent);
     }
     if (pi.hProcess) CloseHandle(pi.hProcess);
     talloc_free(tmp);