Refactor navigator poll rate limiting

4 files changed, 27 insertions, 16 deletions

diff --git a/src/main.c b/src/main.c
index 0d7688e..4bdfe50 100644
--- a/src/main.c
+++ b/src/main.c
@@ -370,9 +370,6 @@ int main(int argc, char** argv)
   unsigned int last_time = SDL_GetTicks();
   unsigned int current_time;
 
-  /* keep file change polling rate under control */
-  static uint8_t poll_countdown = UINT8_MAX;
-
   g_state.need_redraw = 1;
   g_state.need_rescale = 0;
 
@@ -422,7 +419,7 @@ int main(int argc, char** argv)
     }
 
     /* if the user has changed image, start loading the new one */
-    if(imv_navigator_poll_changed(g_state.nav, poll_countdown--)) {
+    if(imv_navigator_poll_changed(g_state.nav)) {
       const char *current_path = imv_navigator_selection(g_state.nav);
       if(!current_path) {
         if(g_options.stdin_list) {
@@ -560,9 +557,6 @@ int main(int argc, char** argv)
       /* redraw complete, unset the flag */
       g_state.need_redraw = 0;
 
-      /* reset poll countdown timer */
-      poll_countdown = UINT8_MAX;
-
       /* tell SDL to show the newly drawn frame */
       SDL_RenderPresent(g_state.renderer);
     }
diff --git a/src/navigator.c b/src/navigator.c
index 6abbfb1..ae7bccd 100644
--- a/src/navigator.c
+++ b/src/navigator.c
@@ -47,6 +47,10 @@ void imv_navigator_free(struct imv_navigator *nav)
     free(nav->mtimes);
   }
 
+  if(nav->ctimes) {
+    free(nav->ctimes);
+  }
+
   free(nav);
 }
 
@@ -56,19 +60,23 @@ static int add_item(struct imv_navigator *nav, const char *path,
   if(nav->num_paths % BUFFER_SIZE == 0) {
     char **new_paths;
     time_t *new_mtimes;
+    time_t *new_ctimes;
     size_t new_size = nav->num_paths + BUFFER_SIZE;
     new_paths = realloc(nav->paths, sizeof(char*) * new_size);
     new_mtimes = realloc(nav->mtimes, sizeof(time_t) * new_size);
-    if (new_paths == NULL || new_mtimes == NULL) {
+    new_ctimes = realloc(nav->ctimes, sizeof(time_t) * new_size);
+    if (new_paths == NULL || new_mtimes == NULL || new_ctimes == NULL) {
       return 1;
     }
     nav->paths = new_paths;
     nav->mtimes = new_mtimes;
+    nav->ctimes = new_ctimes;
   }
   if((nav->paths[nav->num_paths] = strndup(path, PATH_MAX)) == NULL) {
     return 1;
   }
   nav->mtimes[nav->num_paths] = mtime;
+  nav->ctimes[nav->num_paths] = time(NULL);
   nav->num_paths += 1;
   if(nav->num_paths == 1) {
     nav->changed = 1;
@@ -218,7 +226,7 @@ int imv_navigator_find_path(struct imv_navigator *nav, const char *path)
   return -1;
 }
 
-int imv_navigator_poll_changed(struct imv_navigator *nav, const int nopoll)
+int imv_navigator_poll_changed(struct imv_navigator *nav)
 {
   if(nav->changed) {
     nav->changed = 0;
@@ -229,7 +237,11 @@ int imv_navigator_poll_changed(struct imv_navigator *nav, const int nopoll)
     return 0;
   };
 
-  if(!nopoll) {
+  time_t cur_time = time(NULL);
+  /* limit polling to once per second */
+  if(nav->ctimes[nav->cur_path] < cur_time - 1) {
+    nav->ctimes[nav->cur_path] = cur_time;
+
     struct stat file_info;
     if(stat(nav->paths[nav->cur_path], &file_info) == -1) {
       return 0;
diff --git a/src/navigator.h b/src/navigator.h
index 7b7ccf8..0d56fa7 100644
--- a/src/navigator.h
+++ b/src/navigator.h
@@ -27,9 +27,11 @@ struct imv_navigator {
   int cur_path;
   char **paths;
   time_t *mtimes;
+  time_t *ctimes;
   int last_move_direction;
   int changed;
   int wrapped;
+  int poll_countdown;
 };
 
 /* Creates an instance of imv_navigator */
@@ -65,7 +67,7 @@ int imv_navigator_find_path(struct imv_navigator *nav, const char *path);
 
 /* Returns 1 if either the currently selected path or underlying file has
  * changed since last called */
-int imv_navigator_poll_changed(struct imv_navigator *nav, const int nopoll);
+int imv_navigator_poll_changed(struct imv_navigator *nav);
 
 /* Check whether navigator wrapped around paths list */
 int imv_navigator_wrapped(struct imv_navigator *nav);
diff --git a/test/navigator.c b/test/navigator.c
index 2aba317..3f2c50f 100644
--- a/test/navigator.c
+++ b/test/navigator.c
@@ -22,7 +22,7 @@ static void test_navigator_add_remove(void **state)
   struct imv_navigator *nav = imv_navigator_create();
 
   /* Check poll_changed */
-  assert_false(imv_navigator_poll_changed(nav, 0));
+  assert_false(imv_navigator_poll_changed(nav));
 
   /* Add 6 paths, one non-existant should fail */
   assert_false(imv_navigator_add(nav, FILENAME1, 0));
@@ -34,7 +34,7 @@ static void test_navigator_add_remove(void **state)
   assert_int_equal(nav->num_paths, 6);
 
   /* Check poll_changed */
-  assert_true(imv_navigator_poll_changed(nav, 0));
+  assert_true(imv_navigator_poll_changed(nav));
 
   /* Make sure current selection  is #1 */
   assert_string_equal(imv_navigator_selection(nav), FILENAME1);
@@ -87,8 +87,8 @@ static void test_navigator_file_changed(void **state)
   assert_false(futimens(fd, times) == -1);
 
   assert_false(imv_navigator_add(nav, FILENAME1, 0));
-  assert_true(imv_navigator_poll_changed(nav, 0));
-  assert_false(imv_navigator_poll_changed(nav, 0));
+  assert_true(imv_navigator_poll_changed(nav));
+  assert_false(imv_navigator_poll_changed(nav));
 
   assert_false(sleep(1));
 
@@ -101,7 +101,10 @@ static void test_navigator_file_changed(void **state)
   times[1].tv_sec = UTIME_NOW;
   assert_false(futimens(fd, times) == -1);
 
-  assert_true(imv_navigator_poll_changed(nav, 0));
+  /* sleep to ensure we don't hit the poll rate-limiting */
+  sleep(1);
+
+  assert_true(imv_navigator_poll_changed(nav));
 
   (void)close(fd);
   (void)unlink(FILENAME1);