From 21e4e136e4fa35916c8dbe35b40518aae0845a26 Mon Sep 17 00:00:00 2001
From: Andre Noll <maan@tuebingen.mpg.de>
Date: Tue, 24 Oct 2023 23:55:27 +0200
Subject: [PATCH] gui: Implement descriptive tree items.

A restriction of the current gui module is that the text shown in the
menu items must also be a valid identifier for the corresponding bash
function. In particular no whitespace is allowed there.

To overcome this restriction we introduce the concept of a menu item
identifier and an optional menu item description. If the description
is absent, the identifier is used as the description, providing
backward compatibility.
---
 README.md | 58 +++++++++++++++++++++++++++++--------------------------
 gui       | 55 ++++++++++++++++++++++++++++++++++++----------------
 2 files changed, 69 insertions(+), 44 deletions(-)

diff --git a/README.md b/README.md
index ff00e29..bd4bf13 100644
--- a/README.md
+++ b/README.md
@@ -431,23 +431,27 @@ contents of the kernel log buffer. Bash code which defines the menu
 tree could look like this:
 
 		menu_tree='
-			load_average
-			processes
-			hardware/
-				cpu
-				scsi
-			storage/
-				df
-				mdstat
-			log/
-				syslog
-				dmesg
+			load_average System load
+			processes Running processes of a user
+			hardware/ Hardware related information
+				cpu Show prozessor type and features
+				scsi Show SCSI devices
+			storage/ Filesystems and software raid
+				df List of mounted filesystems
+				mdstat Status of software raid arrays
+			log/ System and kernel logs
+				syslog System log
+				dmesg Kernel log
 		'
 
-In this tree, `hardware/`, `storage/` and `log/` are the only
-internal nodes. Note that these are written with a trailing slash
-character while the leaf nodes have no slash at the end. All entries
-of the menu tree must be indented by tab characters.
+Each line of the menu tree consists of an identifier, suffixed with an
+optional slash, and a description. The identifier becomes part of the
+name of a bash function and should only contain alphabetic characters
+and underscores. The description becomes the text shown as the menu
+item. Identifiers suffixed with a slash are regarded as internal nodes
+which represent submenus. In the above tree, `hardware/`, `storage/`
+and `log/` are internal nodes. All entries of the menu tree must be
+properly indented by tab characters.
 
 ___Action handlers___
 
@@ -463,7 +467,7 @@ handler for the `df` node:
 		}
 
 The function name `lsi_df` is derived from the name of the script
-(`lsi`) and the name of the leaf node (`df`). The function simply
+(`lsi`) and the identifier of the leaf node (`df`). The function simply
 passes the output of the `df(1)` command as the first argument to the
 public gsu function `gsu_msgbox()` which runs dialog(1) to display
 a message box that shows the given text.
@@ -503,17 +507,17 @@ tab characters into space characters. The script must be named "lsi".
 		#!/bin/bash
 
 		menu_tree='
-			load_average
-			processes
-			hardware/
-				cpu
-				scsi
-			storage/
-				df
-				mdstat
-			log/
-				syslog
-				dmesg
+			load_average System load
+			processes Running processes of a user
+			hardware/ Hardware related information
+				cpu Show prozessor type and features
+				scsi Show SCSI devices
+			storage/ Filesystems and software raid
+				df List of mounted filesystems
+				mdstat Status of software raid arrays
+			log/ System and kernel logs
+				syslog System log
+				dmesg Kernel log
 		'
 
 		lsi_load_average()
diff --git a/gui b/gui
index fbcbb01..83da0cd 100644
--- a/gui
+++ b/gui
@@ -95,15 +95,16 @@ gsu_msgbox()
 
 _gsu_menu()
 {
-	local header=${1:-root} dflt_item=$2 items=$3
+	local header=$1 dflt_item=$2
 	local geom
 
+	shift 2
 	_get_geometry
 	geom=$result
 	result="$(dialog --no-lines --no-items \
 		--default-item "$dflt_item" \
-		--menu "$gsu_banner_txt ($header)"  \
-		$geom 16 $items 3>&1 1>&2 2>&3 3>&-)"
+		--menu "$gsu_banner_txt"$'\n'"Current location: $header" \
+		$geom 16 "$@" 3>&1 1>&2 2>&3 3>&-)"
 	_set_dialog_ret $?
 }
 
@@ -154,26 +155,46 @@ _get_root_nodes()
 
 _browse()
 {
-	local header=$1 tree=$2
-	local -a subtree=($3)
-	local old_header dflt_item=${subtree[0]}
-
+	local root_item=$1 tree=$2 subtree=$3
+	local -a items arr
+	local -A ids
+	local old_root dflt_item
+	local item id OIFS
+	local -i i=0
+
+	while read -a arr; do
+		((${#arr[@]} == 0)) && continue
+		id=${arr[0]}
+		if ((${#arr[@]} > 1)); then
+			unset arr[0];
+			item=${arr[*]}
+			if [[ "${id:$((${#id} - 1)):1}" == '/' ]]; then
+				item+=/
+			else
+				item="• $item"
+			fi
+		else
+			item=$id
+		fi
+		items[$i]=$item
+		ids["$item"]=$id
+		let i++
+	done <<< "$subtree"
+	dflt_item=${items[0]}
 	while :; do
-		_gsu_menu "$header" "$dflt_item" "${subtree[*]}"
+		_gsu_menu "$root_item" "$dflt_item" "${items[@]}"
 		((ret < 0)) && return
-		dflt_item=$result
 		[[ -z "$result" ]] && return # menu was cancelled
-		if [[ "${result%/}" != "$result" ]]; then
-			old_header="$header"
-			header="$result"
-			_get_subtree "$tree" "$header"
+		dflt_item=$result
+		id=${ids["$result"]}
+		if [[ "${id:$((${#id} - 1)):1}" == '/' ]]; then
+			_get_subtree "$tree" "$id"
 			((ret < 0)) && return
-			_browse "$header" "$tree" "$result"
+			_browse "${dflt_item%/}" "$tree" "$result"
 			((ret < 0)) && return
-			header="$old_header"
 			continue
 		fi
-		eval ${gsu_name}_$result
+		eval ${gsu_name}_${id}
 	done
 }
 
@@ -188,5 +209,5 @@ gsu_gui()
 	fi
 	_get_root_nodes "$tree"
 	subtree="$result"
-	_browse "main menu" "$tree" "$subtree"
+	_browse 'Main menu' "$tree" "$subtree"
 }
-- 
2.39.5