Don't interrogate terminal too often in basta.check_cursor.

- We take advantage of the $EPOCHSECONDS variable available in
  newer Bash to get the current time. We don't perform the
  cursor position or resize check in basta.check_cursor if
  it has been done in the last 5 seconds, in addition to
  continuing to avoid it if there is buffered TTY input.

1 files changed, 30 insertions, 9 deletions

diff --git a/basta.sh b/basta.sh
index 174dbd0..93e943a 100644
--- a/basta.sh
+++ b/basta.sh
@@ -5,6 +5,7 @@
 basta_old_cmdno=${basta_old_cmdno-0}
 basta_old_lines=${basta_old_lines-0}
 basta_old_cols=${basta_old_cols-0}
+basta_last_check_epoch=${basta_last_check_epoch-0}
 
 basta_scroll_lines=${basta_scroll_lines-0}
 basta_prev_reserved_rows=${basta_prev_reserved_rows-}
@@ -58,6 +59,20 @@ basta.get_cur_line()
   printf "%s\n" "$2"
 }
 
+if [ $EPOCHSECONDS ] ; then
+  basta.epoch()
+  {
+    local -n intovar=$1
+    intovar=$EPOCHSECONDS
+  }
+else
+  basta.epoch()
+  {
+    local -n intovar=$1
+    intovar=$(date +%s)
+  }
+fi
+
 basta.update_status()
 {
   local pwd=$PWD
@@ -97,18 +112,24 @@ basta.update_status()
 basta.check_cursor()
 {
   if ! read -t 0; then
-    local exit=$?
-    local curln=$(basta.get_cur_line)
-    local realrows
+    local now
+    basta.epoch now
 
-    if [ $curln ] && [ $curln -gt $basta_scroll_lines ]; then
-      printf $'\e[%s;1H' $basta_scroll_lines
-    fi
+    if [ $((now - 5)) -ge $basta_last_check_epoch ] ; then
+      local exit=$?
+      local curln=$(basta.get_cur_line)
+      local realrows
 
-    basta.query_terminal_lines realrows
+      if [ $curln ] && [ $curln -gt $basta_scroll_lines ]; then
+        printf $'\e[%s;1H' $basta_scroll_lines
+      fi
 
-    [ $LINES -eq $((realrows - $basta_prev_reserved_rows - 1)) ]
-    return $?
+      basta_last_check_epoch=$now
+
+      basta.query_terminal_lines realrows
+      [ $LINES -eq $((realrows - $basta_prev_reserved_rows - 1)) ]
+      return $?
+    fi
   fi
 
   return 0