menubar: quote special chars

- Simplified & renamed nocase function
 - Add pattern-quoting functions to awful.util:
   - awful.util.query_to_pattern
   - awful.util.quote_pattern
 - awful.util: Add basic unit tests for menubar query

Fixes https://github.com/awesomeWM/awesome/issues/84.

lib/awful/util.lua.in

@@ -478,6 +478,39 @@ function util.table.iterate(t, filter, start)
     end
 end
 
+-- Escape all special pattern-matching characters so that lua interprets them
+-- literally instead of as a character class.
+-- Source: http://stackoverflow.com/a/20778724/15690
+function util.quote_pattern(s)
+    -- All special characters escaped in a string: %%, %^, %$, ...
+    local patternchars = '['..("%^$().[]*+-?"):gsub("(.)", "%%%1")..']'
+    return string.gsub(s, patternchars, "%%%1")
+end
+
+-- Generate a pattern matching expression that ignores case.
+-- @param s Original pattern matching expression.
+function util.query_to_pattern(q)
+    s = util.quote_pattern(q)
+    -- Poor man's case-insensitive character matching.
+    s = string.gsub(s, "%a",
+                    function (c)
+                        return string.format("[%s%s]", string.lower(c),
+                                             string.upper(c))
+                    end)
+    return s
+end
+
+function util.unittest()
+    local function testquery(q, s)
+        print('testquery("'..q..'", "'..s..'")')
+        local p = util.query_to_pattern("downlow")
+        local s = "DownLow"
+        assert(s:match(p))
+    end
+    testquery("downlow", "DownLow")
+    testquery("%word", "%word")
+end
+
 return util
 
 -- vim: filetype=lua:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:textwidth=80

lib/menubar/init.lua.in

@@ -79,17 +79,6 @@ local function colortext(s, c)
     return "<span color='" .. c .. "'>" .. s .. "</span>"
 end
 
--- Generate a pattern matching expression that ignores case.
--- @param s Original pattern matching expresion.
-local function nocase (s)
-    s = string.gsub(s, "%a",
-                    function (c)
-                        return string.format("[%s%s]", string.lower(c),
-                                             string.upper(c))
-                    end)
-    return s
-end
-
 -- Get how the menu item should be displayed.
 -- @param o The menu item.
 -- @return item name, item background color, background image, item icon.
@@ -125,6 +114,7 @@ end
 -- @param query The text to filter entries by.
 local function menulist_update(query)
     local query = query or ""
+    local pattern = awful.util.query_to_pattern(query)
     shownitems = {}
     local match_inside = {}
 
@@ -137,8 +127,8 @@ local function menulist_update(query)
         for _, v in pairs(menubar.menu_gen.all_categories) do
             v.focused = false
             if not current_category and v.use then
-                if string.match(v.name, nocase(query)) then
+                if string.match(v.name, pattern) then
-                    if string.match(v.name, "^" .. nocase(query)) then
+                    if string.match(v.name, "^" .. pattern) then
                         table.insert(shownitems, v)
                     else
                         table.insert(match_inside, v)
@@ -152,10 +142,10 @@ local function menulist_update(query)
     for i, v in ipairs(menu_entries) do
         v.focused = false
         if not current_category or v.category == current_category then
-            if string.match(v.name, nocase(query))
+            if string.match(v.name, pattern)
-                or string.match(v.cmdline, nocase(query)) then
+                or string.match(v.cmdline, pattern) then
-                if string.match(v.name, "^" .. nocase(query))
+                if string.match(v.name, "^" .. pattern)
-                    or string.match(v.cmdline, "^" .. nocase(query)) then
+                    or string.match(v.cmdline, "^" .. pattern) then
                     table.insert(shownitems, v)
                 else
                     table.insert(match_inside, v)