api: Add vim_input function and mark vim_feedkeys as deferred

The `vim_feedkeys` must be deferred because it can potentially free the buffer
passed to `os_inchar`(which in turns calls `vim_feedkeys` indirectly).

The new `vim_input` function can be used to emulate user input(Since it does not
mess with the typeahead, it is safe to execute without deferring).

1 files changed, 7 insertions, 0 deletions

diff --git a/src/nvim/os/input.c b/src/nvim/os/input.c
index 1b1a681a8b..d948a48b64 100644
--- a/src/nvim/os/input.c
+++ b/src/nvim/os/input.c
@@ -165,6 +165,13 @@ void input_buffer_restore(String str)
   free(str.data);
 }
 
+size_t input_enqueue(String keys)
+{
+  size_t rv = rbuffer_write(input_buffer, keys.data, keys.size);
+  process_interrupts();
+  return rv;
+}
+
 static bool input_poll(int ms)
 {
   event_poll_until(ms, input_ready());