1 files changed, 62 insertions, 0 deletions
diff --git a/src/nvim/state.c b/src/nvim/state.c
new file mode 100644
index 0000000000..b2f3f0bebe
--- /dev/null
+++ b/src/nvim/state.c
@@ -0,0 +1,62 @@
+#include <assert.h>
+
+#include "nvim/lib/kvec.h"
+
+#include "nvim/state.h"
+#include "nvim/vim.h"
+#include "nvim/getchar.h"
+#include "nvim/ui.h"
+#include "nvim/os/input.h"
+
+#ifdef INCLUDE_GENERATED_DECLARATIONS
+# include "state.c.generated.h"
+#endif
+
+
+void state_enter(VimState *s)
+{
+  for (;;) {
+    int check_result = s->check ? s->check(s) : 1;
+
+    if (!check_result) {
+      break;
+    } else if (check_result == -1) {
+      continue;
+    }
+
+    int key;
+
+getkey:
+    if (char_avail() || using_script() || input_available()) {
+      // Don't block for events if there's a character already available for
+      // processing. Characters can come from mappings, scripts and other
+      // sources, so this scenario is very common.
+      key = safe_vgetc();
+    } else if (!queue_empty(loop.events)) {
+      // Event was made available after the last queue_process_events call
+      key = K_EVENT;
+    } else {
+      input_enable_events();
+      // Flush screen updates before blocking
+      ui_flush();
+      // Call `os_inchar` directly to block for events or user input without
+      // consuming anything from `input_buffer`(os/input.c) or calling the
+      // mapping engine. If an event was put into the queue, we send K_EVENT
+      // directly.
+      (void)os_inchar(NULL, 0, -1, 0);
+      input_disable_events();
+      key = !queue_empty(loop.events) ? K_EVENT : safe_vgetc();
+    }
+
+    if (key == K_EVENT) {
+      may_sync_undo();
+    }
+
+    int execute_result = s->execute(s, key);
+    if (!execute_result) {
+      break;
+    } else if (execute_result == -1) {
+      goto getkey;
+    }
+  }
+}