Similar to r251236, improve the portion of dialog(1) API in dialog.subr

responsible for retrieving stored input (for the --inputbox and --password
widgets).

When we (Ron McDowell and I) developed the first version of bsdconfig, it
used temporary files to store responses from dialog(1). That hasn't been
true for a very long time, so the need to always execute some clean-up
function is long-deprecated. The function that used to perform these clean-
up routines for these widgets was f_dialog_inputstr().

We really don't need f_dialog_inputstr() for its originally designed purpose
as all dialog invocations no longer require temporary files.

Just as in r251236, redesign f_dialog_inputstr() in the following four ways:

1. Rename f_dialog_inputstr() to f_dialog_inputstr_fetch()
2. Introduce the new first-argument of $var_to_set to reduce forking
3. Create a corresponding f_dialog_inputstr_store() to abstract storage
4. Offload the sanitization to a new function, f_dialog_line_sanitize()

It should be noted that f_dialog_line_sanitize() -- unlike its cousin from
SVN r251236, f_dialog_data_sanitize() -- trims leading/trailing whitespace
from the user's input. This helps prevent errors and common mistakes caused
by the fact that the new cdialog implementation allows the right-arrow
cursor key to go beyond the last byte of realtime input (adding whitespace
at the end of the typed value).

While we're centralizing the sanitization, let's rewrite f_dialog_input()
while we're here to likewise reduce forking. The f_dialog_input() function
now expects the first argument of $var_to_set instead of producing results
on standard-out.

These changes greatly improve readability and also improve performance.

3 files changed, 5 insertions, 7 deletions

diff --git a/usr.sbin/bsdconfig/startup/misc b/usr.sbin/bsdconfig/startup/misc
index c964129806eb..6e33462456ff 100755
--- a/usr.sbin/bsdconfig/startup/misc
+++ b/usr.sbin/bsdconfig/startup/misc
@@ -303,7 +303,7 @@ dialog_input_value()
 	local prompt="$1" _input="$2"
 
 	f_dialog_title "$msg_value_required"
-	_input=$( f_dialog_input "$prompt" "$_input" "$hline_alnum_tab_enter" )
+	f_dialog_input _input "$prompt" "$_input" "$hline_alnum_tab_enter"
 	local retval=$?
 	f_dialog_title_restore
 
diff --git a/usr.sbin/bsdconfig/startup/share/rcconf.subr b/usr.sbin/bsdconfig/startup/share/rcconf.subr
index 1c641378ebff..ed8553ab9021 100644
--- a/usr.sbin/bsdconfig/startup/share/rcconf.subr
+++ b/usr.sbin/bsdconfig/startup/share/rcconf.subr
@@ -454,9 +454,8 @@ f_dialog_input_rcvar()
 	while :; do
 
 		# Return if user either pressed ESC or chosen Cancel/No
-		_input=$( f_dialog_input "$msg_please_enter_rcvar_name" \
-		                         "$_input" "$hline_alnum_tab_enter"
-		        ) || return
+		f_dialog_input _input "$msg_please_enter_rcvar_name" \
+		               "$_input" "$hline_alnum_tab_enter" || return
 
 		# Check for invalid entry (1of2)
 		if ! echo "$_input" | grep -q "^[[:alpha:]_]"; then
diff --git a/usr.sbin/bsdconfig/startup/share/rcedit.subr b/usr.sbin/bsdconfig/startup/share/rcedit.subr
index cb4a4116961e..64ee1ccf0d84 100644
--- a/usr.sbin/bsdconfig/startup/share/rcedit.subr
+++ b/usr.sbin/bsdconfig/startup/share/rcedit.subr
@@ -68,9 +68,8 @@ f_dialog_rcedit()
 	fi
 
 	# Return if user has either pressed ESC or chosen Cancel/No
-	_input=$( f_dialog_input "$msg" "$_input" \
-	                         "$hline_alnum_punc_tab_enter"
-	        ) || return
+	f_dialog_input _input "$msg" "$_input" \
+	               "$hline_alnum_punc_tab_enter" || return
 
 	# Return if the value has not changed from current
 	local cur_val="$( f_sysrc_get "$var" )"