From: Andre Noll <maan@tuebingen.mpg.de>
Date: Mon, 1 Sep 2014 22:23:41 +0000 (+0200)
Subject: gui: Conform to $ret and $result conventions.
X-Git-Url: http://git.tuebingen.mpg.de/?p=gsu.git;a=commitdiff_plain;h=2925cf7299f958ed6c52ba1ba9d42a841d86c8f2;ds=sidebyside

gui: Conform to $ret and $result conventions.

Unlike the rest of gsu, the functions of the gui module did not follow
the rule that functions should always set $ret to indicate error or
success, and $result to either the result of the function (if any)
or to an error context string. This commit makes all functions of
the gui module conform to this rule.

This patch also improves the error handling of _gsu_menu(). This
function should distinguish between three cases, according to the
exit code of dialog(1): OK (user selected the OK button), Cancel
(user pressed the escape key or selected the Cancel button), and error
(dialog(1) failed to execute or returned unsuccessfully).

The old code does not distinguish between the last two cases. Hence one
could not exit the application by pressing CTRL+C from a menu. This
patch changes _gsu_menu() to look more carefully at the exit code of
dialog(1) to tell apart the "error" case and the "cancel" case.
---

diff --git a/common b/common
index eaa5751..cd07252 100644
--- a/common
+++ b/common
@@ -15,6 +15,9 @@ E_GSU_BAD_ARG_COUNT		invalid number of arguments
 E_GSU_EDITOR			failed to execute editor
 E_GSU_MKDIR			failed to create directory
 E_GSU_GETOPTS			getopts error
+E_GSU_DIALOG			dialog error
+E_GSU_MKTEMP			mktemp error
+E_GSU_MENU_TREE			invalid menu tree
 $gsu_errors
 "
 	local a b i=0
diff --git a/gui b/gui
index 336d154..3c89567 100644
--- a/gui
+++ b/gui
@@ -29,15 +29,25 @@ gsu_inputbox()
 	_get_geometry
 	g="$result"
 	result="$(dialog --inputbox "$text" $g "$init" 3>&1 1>&2 2>&3 3>&-)"
-	ret="$?"
+	if (($? != 0)); then
+		ret=-$E_GSU_DIALOG
+		result='inputbox'
+		return
+	fi
+	ret=$GSU_SUCCESS
 }
 
 gsu_textbox()
 {
-	local file="$1"
+	local g file="$1"
 
 	_get_geometry
-	dialog --textbox "$file" $result
+	g="$result"
+
+	ret=-$E_GSU_DIALOG
+	result='textbox'
+	dialog --textbox "$file" $g || return
+	ret=$GSU_SUCCESS
 }
 
 # dialog segfaults if message is too long. Hence we always use a temporary file
@@ -46,12 +56,13 @@ gsu_msgbox()
 	local tmp="$(mktemp gsu_msgbox.XXXXXXXXXX)"
 
 	if (($? != 0)); then
-		dialog --msgbox "mktemp error" 0 0
+		ret=-$E_GSU_MKTEMP
+		result='temp file for textbox'
 		return
 	fi
 	echo "$1" > "$tmp"
 	gsu_textbox "$tmp"
-	rm -f "$tmp"
+	rm -f "$tmp" # ignore errors
 }
 
 _gsu_menu()
@@ -67,7 +78,13 @@ _gsu_menu()
 		opts+=" $i $num"
 	done
 	result="$(dialog --menu "$gsu_banner_txt ($header)" $opts 3>&1 1>&2 2>&3 3>&-)"
-	ret="$?"
+	case $? in
+	0) ret=$GSU_SUCCESS;;
+	1) ret=1;; # cancelled
+	*)
+		result="menu error $ret"
+		ret=-$E_GSU_DIALOG
+	esac
 }
 
 _get_level()
@@ -81,7 +98,9 @@ _get_subtree()
 	local tree="$1" root="${2%/}"
 	local first TAB='	'
 
-	first="$(grep -n "$TAB\{1,\}$root/" <<< "$tree")"
+	ret=-$E_GSU_MENU_TREE
+	result="subtree grep failed"
+	first="$(grep -n "$TAB\{1,\}$root/" <<< "$tree")" || return
 	[[ -z "$first" ]] && return
 
 	line_num="${first%%:*}"
@@ -92,7 +111,12 @@ _get_subtree()
 	result="$(sed -e "1,${line_num}d;" <<< "$tree" \
 		| sed -e "/^$TAB\{1,$level\}$_gsu_node_name_pattern/,\$d" \
 		| sed -e "/^$TAB\{$(($level + 2))\}/d")"
-	ret="$level"
+	if (($? != 0)); then
+		ret=-$E_GSU_MENU_TREE
+		result="sed command for subtree $root failed"
+		return
+	fi
+	ret=$GSU_SUCCESS
 }
 
 _get_root_nodes()
@@ -100,6 +124,12 @@ _get_root_nodes()
 	local tree="$1" TAB='	'
 
 	result="$(grep "^${TAB}${_gsu_node_name_pattern}" <<< "$tree")"
+	if (($? != 0)); then
+		ret=-$E_GSU_MENU_TREE
+		result="root node grep failed"
+		return
+	fi
+	ret=$GSU_SUCCESS
 }
 
 _browse()
@@ -109,13 +139,15 @@ _browse()
 
 	while :; do
 		_gsu_menu "$header" "$subtree"
-		(($ret != 0)) && return
-		[[ -z "$result" ]] && return
+		(($ret < 0)) && return
+		[[ -z "$result" ]] && return # menu was cancelled
 		if [[ "${result%/}" != "$result" ]]; then
 			old_header="$header"
 			header="$result"
 			_get_subtree "$tree" "$header"
+			(($ret < 0)) && return
 			_browse "$header" "$tree" "$result"
+			(($ret < 0)) && return
 			header="$old_header"
 			continue
 		fi