check the life time of subprocesses before freeing vis

Currently there is now way for long running subprocesses like language
servers to gracefully shutdown.
When reacting to the QUIT event and invalidating the process handle
the subprocess will never be killed and destroyed because the
subprocesses are only checked during vis_run.

Collecting and killing subprocesses with invalid handles after the
QUIT event allows graceful shutdown.

3 files changed, 18 insertions, 0 deletions

diff --git a/vis-subprocess.c b/vis-subprocess.c
index 31a1479..e17d24f 100644
--- a/vis-subprocess.c
+++ b/vis-subprocess.c
@@ -230,3 +230,19 @@ void vis_process_tick(Vis *vis, fd_set *readfds) {
 		}
 	}
 }
+
+/**
+ * Checks if each subprocess from the pool is dead or needs to be
+ * killed then raises an event or kills it if necessary.
+ */
+void vis_process_waitall(Vis *vis) {
+	for (Process **pointer = &process_pool; *pointer; ) {
+		Process *current = *pointer;
+		if (!wait_or_kill_process(vis, current)) {
+			pointer = &current->next;
+		} else {
+			/* update our iteration pointer */
+			*pointer = destroy_process(current);
+		}
+	}
+}
diff --git a/vis-subprocess.h b/vis-subprocess.h
index 2e4c222..79a043e 100644
--- a/vis-subprocess.h
+++ b/vis-subprocess.h
@@ -27,4 +27,5 @@ Process *vis_process_communicate(Vis *, const char *command, const char *name,
                                  Invalidator **invalidator);
 int vis_process_before_tick(fd_set *);
 void vis_process_tick(Vis *, fd_set *);
+void vis_process_waitall(Vis *);
 #endif
diff --git a/vis.c b/vis.c
index 10c3df5..d1c0dab 100644
--- a/vis.c
+++ b/vis.c
@@ -623,6 +623,7 @@ void vis_free(Vis *vis) {
 	while (vis->windows)
 		vis_window_close(vis->windows);
 	vis_event_emit(vis, VIS_EVENT_QUIT);
+	vis_process_waitall(vis);
 	file_free(vis, vis->command_file);
 	file_free(vis, vis->search_file);
 	file_free(vis, vis->error_file);