4 files changed, 58 insertions, 30 deletions

diff --git a/src/nvim/event/defs.h b/src/nvim/event/defs.h
index 5126d52241..b802866a3d 100644
--- a/src/nvim/event/defs.h
+++ b/src/nvim/event/defs.h
@@ -4,7 +4,7 @@
 #include <assert.h>
 #include <stdarg.h>
 
-#define EVENT_HANDLER_MAX_ARGC 4
+#define EVENT_HANDLER_MAX_ARGC 6
 
 typedef void (*argv_callback)(void **argv);
 typedef struct message {
@@ -12,6 +12,7 @@ typedef struct message {
   argv_callback handler;
   void *argv[EVENT_HANDLER_MAX_ARGC];
 } Event;
+typedef void(*event_scheduler)(Event event, void *data);
 
 #define VA_EVENT_INIT(event, p, h, a)                   \
   do {                                                  \
diff --git a/src/nvim/event/loop.c b/src/nvim/event/loop.c
index 3d3288f858..088e059d19 100644
--- a/src/nvim/event/loop.c
+++ b/src/nvim/event/loop.c
@@ -10,20 +10,19 @@
 # include "event/loop.c.generated.h"
 #endif
 
-typedef struct idle_event {
-  uv_idle_t idle;
-  Event event;
-} IdleEvent;
-
 
 void loop_init(Loop *loop, void *data)
 {
   uv_loop_init(&loop->uv);
+  loop->recursive = 0;
   loop->uv.data = loop;
   loop->children = kl_init(WatcherPtr);
   loop->children_stop_requests = 0;
   loop->events = queue_new_parent(loop_on_put, loop);
   loop->fast_events = queue_new_child(loop->events);
+  loop->thread_events = queue_new_parent(NULL, NULL);
+  uv_mutex_init(&loop->mutex);
+  uv_async_init(&loop->uv, &loop->async, async_cb);
   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);
@@ -31,9 +30,7 @@ void loop_init(Loop *loop, void *data)
 
 void loop_poll_events(Loop *loop, int ms)
 {
-  static int recursive = 0;
-
-  if (recursive++) {
+  if (loop->recursive++) {
     abort();  // Should not re-enter uv_run
   }
 
@@ -55,10 +52,19 @@ void loop_poll_events(Loop *loop, int ms)
     uv_timer_stop(&loop->poll_timer);
   }
 
-  recursive--;  // Can re-enter uv_run now
+  loop->recursive--;  // Can re-enter uv_run now
   queue_process_events(loop->fast_events);
 }
 
+// Schedule an event from another thread
+void loop_schedule(Loop *loop, Event event)
+{
+  uv_mutex_lock(&loop->mutex);
+  queue_put_event(loop->thread_events, event);
+  uv_async_send(&loop->async);
+  uv_mutex_unlock(&loop->mutex);
+}
+
 void loop_on_put(Queue *queue, void *data)
 {
   Loop *loop = data;
@@ -72,14 +78,32 @@ void loop_on_put(Queue *queue, void *data)
 
 void loop_close(Loop *loop)
 {
+  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->async, NULL);
   do {
     uv_run(&loop->uv, UV_RUN_DEFAULT);
   } while (uv_loop_close(&loop->uv));
+  queue_free(loop->events);
+  queue_free(loop->fast_events);
+  queue_free(loop->thread_events);
+  kl_destroy(WatcherPtr, loop->children);
+}
+
+static void async_cb(uv_async_t *handle)
+{
+  Loop *l = handle->loop->data;
+  uv_mutex_lock(&l->mutex);
+  while (!queue_empty(l->thread_events)) {
+    Event ev = queue_get(l->thread_events);
+    queue_put_event(l->fast_events, ev);
+  }
+  uv_mutex_unlock(&l->mutex);
 }
 
 static void timer_cb(uv_timer_t *handle)
 {
 }
+
diff --git a/src/nvim/event/loop.h b/src/nvim/event/loop.h
index 9212a45aa4..0c1fcb5ed9 100644
--- a/src/nvim/event/loop.h
+++ b/src/nvim/event/loop.h
@@ -16,11 +16,14 @@ KLIST_INIT(WatcherPtr, WatcherPtr, _noop)
 
 typedef struct loop {
   uv_loop_t uv;
-  Queue *events, *fast_events;
+  Queue *events, *fast_events, *thread_events;
   klist_t(WatcherPtr) *children;
   uv_signal_t children_watcher;
   uv_timer_t children_kill_timer, poll_timer;
   size_t children_stop_requests;
+  uv_async_t async;
+  uv_mutex_t mutex;
+  int recursive;
 } Loop;
 
 #define CREATE_EVENT(queue, handler, argc, ...)                  \
diff --git a/src/nvim/event/queue.c b/src/nvim/event/queue.c
index 19eca14144..c5ef22d426 100644
--- a/src/nvim/event/queue.c
+++ b/src/nvim/event/queue.c
@@ -105,16 +105,15 @@ static Queue *queue_new(Queue *parent, put_callback put_cb, void *data)
 void queue_free(Queue *queue)
 {
   assert(queue);
-  if (queue->parent) {
-    while (!QUEUE_EMPTY(&queue->headtail)) {
-      QUEUE *q = QUEUE_HEAD(&queue->headtail);
-      QueueItem *item = queue_node_data(q);
-      assert(!item->link);
+  while (!QUEUE_EMPTY(&queue->headtail)) {
+    QUEUE *q = QUEUE_HEAD(&queue->headtail);
+    QueueItem *item = queue_node_data(q);
+    if (queue->parent) {
       QUEUE_REMOVE(&item->data.item.parent->node);
       xfree(item->data.item.parent);
-      QUEUE_REMOVE(q);
-      xfree(item);
     }
+    QUEUE_REMOVE(q);
+    xfree(item);
   }
 
   xfree(queue);
@@ -128,9 +127,8 @@ Event queue_get(Queue *queue)
 void queue_put_event(Queue *queue, Event event)
 {
   assert(queue);
-  assert(queue->parent);  // don't push directly to the parent queue
   queue_push(queue, event);
-  if (queue->parent->put_cb) {
+  if (queue->parent && queue->parent->put_cb) {
     queue->parent->put_cb(queue->parent, queue->parent->data);
   }
 }
@@ -177,11 +175,11 @@ static Event queue_remove(Queue *queue)
     rv = child->data.item.event;
     xfree(child);
   } else {
-    assert(queue->parent);
-    assert(!queue_empty(queue->parent));
-    // remove the corresponding link node in the parent queue
-    QUEUE_REMOVE(&item->data.item.parent->node);
-    xfree(item->data.item.parent);
+    if (queue->parent) {
+      // remove the corresponding link node in the parent queue
+      QUEUE_REMOVE(&item->data.item.parent->node);
+      xfree(item->data.item.parent);
+    }
     rv = item->data.item.event;
   }
 
@@ -195,11 +193,13 @@ static void queue_push(Queue *queue, Event event)
   item->link = false;
   item->data.item.event = event;
   QUEUE_INSERT_TAIL(&queue->headtail, &item->node);
-  // push link node to the parent queue
-  item->data.item.parent = xmalloc(sizeof(QueueItem));
-  item->data.item.parent->link = true;
-  item->data.item.parent->data.queue = queue;
-  QUEUE_INSERT_TAIL(&queue->parent->headtail, &item->data.item.parent->node);
+  if (queue->parent) {
+    // push link node to the parent queue
+    item->data.item.parent = xmalloc(sizeof(QueueItem));
+    item->data.item.parent->link = true;
+    item->data.item.parent->data.queue = queue;
+    QUEUE_INSERT_TAIL(&queue->parent->headtail, &item->data.item.parent->node);
+  }
 }
 
 static QueueItem *queue_node_data(QUEUE *q)