lib/helpers: new functions _bash_it_history_auto_*()

Two new functions `_bash_it_history_auto_save()` and `_bash_it_history_auto_load()`, which append new history to disk and load new history from disk, respectively.

See Bash-it#1595 for discussion.

lib/helpers.bash

@@ -954,6 +954,44 @@ function safe_append_preexec {
  fi
 }
 
-function _save-and-reload-history() {
- [[ ${autosave:-0} -eq 1 ]] && history -a && history -c && history -r
+function _save-and-reload-history()
+{
+ [[ ${autosave:-${HISTORY_AUTOSAVE:-0}} -eq 1 ]] && local HISTCONTROL="${HISTCONTROL:-}${HISTCONTROL:+:}autoshare"
+ _bash_it_history_auto_save && _bash_it_history_auto_load
+}
+
+function _bash_it_history_auto_save()
+{
+ case $HISTCONTROL in
+ *'noauto'*|*'autoload'*)
+ : # Do nothing, as configured.
+ ;;
+ *'auto'*)
+ # Append new history from this session to the $HISTFILE
+ history -a
+ ;;
+ *)
+ : # Do nothing, default.
+ ;;
+ esac
+}
+
+function _bash_it_history_auto_load()
+{
+ case $HISTCONTROL in
+ *'noauto'*|*'autosave'*)
+ : # Do nothing, as configured.
+ ;;
+ *'autoloadnew'*)
+ # Read new entries from $HISTFILE
+ history -n
+ ;;
+ *'auto'*)
+ # Blank in-memory history, then read entire $HISTFILE fresh from disk.
+ history -c && history -r
+ ;;
+ *)
+ : # Do nothing, default.
+ ;;
+ esac
 }