refactor(time): refactor delay with input checking

Previously, there were three low-level delay entry points

- os_delay(ms, ignoreinput=true): sleep for ms, only break on got_int

- os_delay(ms, ignoreinput=false): sleep for ms, break on any key input
  os_microdelay(us, false): equivalent, but in μs (not directly called)

- os_microdelay(us, true): sleep for μs, never break.

The implementation of the latter two both used uv_cond_timedwait()
This could have been for two reasons:
 1. allow another thread to "interrupt" the wait
 2. uv_cond_timedwait() has higher resolution than uv_sleep()

However we (1) never used the first, even when TUI was a thread, and
(2) nowhere in the codebase are we using μs resolution, it is always a ms
multiplied with 1000.

In addition, os_delay(ms, false) would completely block the thread for
100ms intervals and in between check for input. This is not how event handling
is done alound here.

Therefore:

Replace the implementation of os_delay(ms, false) to use
LOOP_PROCESS_EVENTS_UNTIL which does a proper epoll wait with a timeout,
instead of the 100ms timer panic.

Replace os_microdelay(us, false) with a direct wrapper of uv_sleep.

src/nvim/main.c

@@ -173,7 +173,7 @@ bool event_teardown(void)
 
 /// Performs early initialization.
 ///
-/// Needed for unit tests. Must be called after `time_init()`.
+/// Needed for unit tests.
 void early_init(mparm_T *paramp)
 {
   estack_init();
@@ -261,7 +261,6 @@ int main(int argc, char **argv)
   mparm_T params;         // various parameters passed between
                           // main() and other functions.
   char *cwd = NULL;       // current working dir on startup
-  time_init();
 
   // Many variables are in `params` so that we can pass them around easily.
   // `argc` and `argv` are also copied, so that they can be changed.

src/nvim/os/input.c

@@ -441,7 +441,7 @@ bool input_blocking(void)
 // This is a replacement for the old `WaitForChar` function in os_unix.c
 static InbufPollResult inbuf_poll(int ms, MultiQueue *events)
 {
-  if (input_ready(events)) {
+  if (os_input_ready(events)) {
     return kInputAvail;
   }
 
@@ -457,14 +457,14 @@ static InbufPollResult inbuf_poll(int ms, MultiQueue *events)
   DLOG("blocking... events_enabled=%d events_pending=%d", events != NULL,
        events && !multiqueue_empty(events));
   LOOP_PROCESS_EVENTS_UNTIL(&main_loop, NULL, ms,
-                            input_ready(events) || input_eof);
+                            os_input_ready(events) || input_eof);
   blocking = false;
 
   if (do_profiling == PROF_YES && ms) {
     prof_inchar_exit();
   }
 
-  if (input_ready(events)) {
+  if (os_input_ready(events)) {
     return kInputAvail;
   }
   return input_eof ? kInputEof : kInputNone;
@@ -530,8 +530,8 @@ static int push_event_key(uint8_t *buf, int maxlen)
   return buf_idx;
 }
 
-// Check if there's pending input
-static bool input_ready(MultiQueue *events)
+/// Check if there's pending input already in typebuf or `events`
+bool os_input_ready(MultiQueue *events)
 {
   return (typebuf_was_filled             // API call filled typeahead
           || rbuffer_size(input_buffer)  // Input buffer filled

src/nvim/os/time.c

@@ -24,20 +24,10 @@
 
 struct tm;
 
-static uv_mutex_t delay_mutex;
-static uv_cond_t delay_cond;
-
 #ifdef INCLUDE_GENERATED_DECLARATIONS
 # include "os/time.c.generated.h"  // IWYU pragma: export
 #endif
 
-/// Initializes the time module
-void time_init(void)
-{
-  uv_mutex_init(&delay_mutex);
-  uv_cond_init(&delay_cond);
-}
-
 /// Gets a high-resolution (nanosecond), monotonically-increasing time relative
 /// to an arbitrary time in the past.
 ///
@@ -73,55 +63,28 @@ uint64_t os_now(void)
 void os_delay(uint64_t ms, bool ignoreinput)
 {
   DLOG("%" PRIu64 " ms", ms);
-  if (ignoreinput) {
   if (ms > INT_MAX) {
     ms = INT_MAX;
   }
-    LOOP_PROCESS_EVENTS_UNTIL(&main_loop, NULL, (int)ms, got_int);
-  } else {
-    os_microdelay(ms * 1000U, ignoreinput);
-  }
+  LOOP_PROCESS_EVENTS_UNTIL(&main_loop, NULL, (int)ms,
+                            ignoreinput ? got_int : os_input_ready(NULL));
 }
 
-/// Sleeps for `us` microseconds.
+/// Sleeps for `ms` milliseconds without checking for events or interrupts.
+///
+/// This blocks even "fast" events which is quite disruptive. This should only
+/// be used in debug code. Prefer os_delay() and decide if the delay should be
+/// interupted by input or only a CTRL-C.
 ///
 /// @see uv_sleep() (libuv v1.34.0)
 ///
 /// @param us          Number of microseconds to sleep.
-/// @param ignoreinput If true, ignore all input (including SIGINT/CTRL-C).
-///                    If false, waiting is aborted on any input.
-void os_microdelay(uint64_t us, bool ignoreinput)
+void os_sleep(uint64_t ms)
 {
-  uint64_t elapsed = 0U;
-  uint64_t base = uv_hrtime();
-  // Convert microseconds to nanoseconds, or UINT64_MAX on overflow.
-  const uint64_t ns = (us < UINT64_MAX / 1000U) ? us * 1000U : UINT64_MAX;
-
-  uv_mutex_lock(&delay_mutex);
-
-  while (elapsed < ns) {
-    // If ignoring input, we simply wait the full delay.
-    // Else we check for input in ~100ms intervals.
-    const uint64_t ns_delta = ignoreinput
-                              ? ns - elapsed
-                              : MIN(ns - elapsed, 100000000U);  // 100ms
-
-    const int rv = uv_cond_timedwait(&delay_cond, &delay_mutex, ns_delta);
-    if (0 != rv && UV_ETIMEDOUT != rv) {
-      abort();
-      break;
-    }  // Else: Timeout proceeded normally.
-
-    if (!ignoreinput && os_char_avail()) {
-      break;
+  if (ms > UINT_MAX) {
+    ms = UINT_MAX;
   }
-
-    const uint64_t now = uv_hrtime();
-    elapsed += now - base;
-    base = now;
-  }
-
-  uv_mutex_unlock(&delay_mutex);
+  uv_sleep((unsigned)ms);
 }
 
 // Cache of the current timezone name as retrieved from TZ, or an empty string

src/nvim/ui.c

@@ -439,7 +439,7 @@ void ui_line(ScreenGrid *grid, int row, int startcol, int endcol, int clearcol,
                              MIN(clearcol, (int)grid->cols - 1));
     ui_call_flush();
     uint64_t wd = (uint64_t)labs(p_wd);
-    os_microdelay(wd * 1000U, true);
+    os_sleep(wd);
     pending_cursor_update = true;  // restore the cursor later
   }
 }
@@ -521,7 +521,7 @@ void ui_flush(void)
   ui_call_flush();
 
   if (p_wd && (rdb_flags & RDB_FLUSH)) {
-    os_microdelay((uint64_t)labs(p_wd) * 1000U, true);
+    os_sleep((uint64_t)labs(p_wd));
   }
 }
 

src/nvim/ui_compositor.c

@@ -467,7 +467,7 @@ static void debug_delay(Integer lines)
   ui_call_flush();
   uint64_t wd = (uint64_t)labs(p_wd);
   uint64_t factor = (uint64_t)MAX(MIN(lines, 5), 1);
-  os_microdelay(factor * wd * 1000U, true);
+  os_sleep(factor * wd);
 }
 
 static void compose_area(Integer startrow, Integer endrow, Integer startcol, Integer endcol)

test/unit/helpers.lua

@@ -97,7 +97,6 @@ local init = only_separate(function()
   for _, c in ipairs(child_calls_init) do
     c.func(unpack(c.args))
   end
-  libnvim.time_init()
   libnvim.fs_init()
   libnvim.event_init()
   libnvim.early_init(nil)