1 files changed, 66 insertions, 11 deletions

diff --git a/src/nvim/event/loop.c b/src/nvim/event/loop.c
index 0e1775d01b..7998e0b8d0 100644
--- a/src/nvim/event/loop.c
+++ b/src/nvim/event/loop.c
@@ -1,3 +1,6 @@
+// This is an open source non-commercial project. Dear PVS-Studio, please check
+// it. PVS-Studio Static Code Analyzer for C, C++ and C#: http://www.viva64.com
+
 #include <stdarg.h>
 #include <stdint.h>
 
@@ -5,6 +8,7 @@
 
 #include "nvim/event/loop.h"
 #include "nvim/event/process.h"
+#include "nvim/log.h"
 
 #ifdef INCLUDE_GENERATED_DECLARATIONS
 # include "event/loop.c.generated.h"
@@ -17,7 +21,6 @@ void loop_init(Loop *loop, void *data)
   loop->recursive = 0;
   loop->uv.data = loop;
   loop->children = kl_init(WatcherPtr);
-  loop->children_stop_requests = 0;
   loop->events = multiqueue_new_parent(loop_on_put, loop);
   loop->fast_events = multiqueue_new_child(loop->events);
   loop->thread_events = multiqueue_new_parent(NULL, NULL);
@@ -26,37 +29,51 @@ void loop_init(Loop *loop, void *data)
   uv_signal_init(&loop->uv, &loop->children_watcher);
   uv_timer_init(&loop->uv, &loop->children_kill_timer);
   uv_timer_init(&loop->uv, &loop->poll_timer);
+  loop->poll_timer.data = xmalloc(sizeof(bool));  // "timeout expired" flag
 }
 
-void loop_poll_events(Loop *loop, int ms)
+/// Processes one `Loop.uv` event (at most).
+/// Processes all `Loop.fast_events` events.
+///
+/// @returns true if `ms` timeout was reached
+bool loop_poll_events(Loop *loop, int ms)
 {
   if (loop->recursive++) {
     abort();  // Should not re-enter uv_run
   }
 
   uv_run_mode mode = UV_RUN_ONCE;
+  bool timeout_expired = false;
 
   if (ms > 0) {
-    // Use a repeating timeout of ms milliseconds to make sure
-    // we do not block indefinitely for I/O.
+    *((bool *)loop->poll_timer.data) = false;  // reset "timeout expired" flag
+    // Dummy timer to ensure UV_RUN_ONCE does not block indefinitely for I/O.
     uv_timer_start(&loop->poll_timer, timer_cb, (uint64_t)ms, (uint64_t)ms);
   } else if (ms == 0) {
-    // For ms == 0, we need to do a non-blocking event poll by
-    // setting the run mode to UV_RUN_NOWAIT.
+    // For ms == 0, do a non-blocking event poll.
     mode = UV_RUN_NOWAIT;
   }
 
   uv_run(&loop->uv, mode);
 
   if (ms > 0) {
+    timeout_expired = *((bool *)loop->poll_timer.data);
     uv_timer_stop(&loop->poll_timer);
   }
 
   loop->recursive--;  // Can re-enter uv_run now
   multiqueue_process_events(loop->fast_events);
+  return timeout_expired;
 }
 
-// Schedule an event from another thread
+/// Schedules an event from another thread.
+///
+/// @note Event is queued into `fast_events`, which is processed outside of the
+///       primary `events` queue by loop_poll_events(). For `main_loop`, that
+///       means `fast_events` is NOT processed in an "editor mode"
+///       (VimState.execute), so redraw and other side-effects are likely to be
+///       skipped.
+/// @see loop_schedule_deferred
 void loop_schedule(Loop *loop, Event event)
 {
   uv_mutex_lock(&loop->mutex);
@@ -65,6 +82,24 @@ void loop_schedule(Loop *loop, Event event)
   uv_mutex_unlock(&loop->mutex);
 }
 
+/// Schedules an event from another thread. Unlike loop_schedule(), the event
+/// is forwarded to `Loop.events`, instead of being processed immediately.
+///
+/// @see loop_schedule
+void loop_schedule_deferred(Loop *loop, Event event)
+{
+  Event *eventp = xmalloc(sizeof(*eventp));
+  *eventp = event;
+  loop_schedule(loop, event_create(loop_deferred_event, 2, loop, eventp));
+}
+static void loop_deferred_event(void **argv)
+{
+  Loop *loop = argv[0];
+  Event *eventp = argv[1];
+  multiqueue_put_event(loop->events, *eventp);
+  xfree(eventp);
+}
+
 void loop_on_put(MultiQueue *queue, void *data)
 {
   Loop *loop = data;
@@ -76,20 +111,34 @@ void loop_on_put(MultiQueue *queue, void *data)
   uv_stop(&loop->uv);
 }
 
-void loop_close(Loop *loop, bool wait)
+/// @returns false if the loop could not be closed gracefully
+bool loop_close(Loop *loop, bool wait)
 {
+  bool rv = true;
   uv_mutex_destroy(&loop->mutex);
   uv_close((uv_handle_t *)&loop->children_watcher, NULL);
   uv_close((uv_handle_t *)&loop->children_kill_timer, NULL);
-  uv_close((uv_handle_t *)&loop->poll_timer, NULL);
+  uv_close((uv_handle_t *)&loop->poll_timer, timer_close_cb);
   uv_close((uv_handle_t *)&loop->async, NULL);
-  do {
+  uint64_t start = wait ? os_hrtime() : 0;
+  while (true) {
     uv_run(&loop->uv, wait ? UV_RUN_DEFAULT : UV_RUN_NOWAIT);
-  } while (uv_loop_close(&loop->uv) && wait);
+    if (!uv_loop_close(&loop->uv) || !wait) {
+      break;
+    }
+    if (os_hrtime() - start >= 2 * 1000000000) {
+      // Some libuv resource was not correctly deref'd. Log and bail.
+      rv = false;
+      ELOG("uv_loop_close() hang?");
+      log_uv_handles(&loop->uv);
+      break;
+    }
+  }
   multiqueue_free(loop->fast_events);
   multiqueue_free(loop->thread_events);
   multiqueue_free(loop->events);
   kl_destroy(WatcherPtr, loop->children);
+  return rv;
 }
 
 void loop_purge(Loop *loop)
@@ -121,5 +170,11 @@ static void async_cb(uv_async_t *handle)
 
 static void timer_cb(uv_timer_t *handle)
 {
+  bool *timeout_expired = handle->data;
+  *timeout_expired = true;
 }
 
+static void timer_close_cb(uv_handle_t *handle)
+{
+  xfree(handle->data);
+}