[RTL UI] Bidi wrapping tweaks

- Alias everything to Bidi.nowrap() when in LTR UI, as using
  LTR isolates seems uneeded when already LTR.
- Better wrapping of RTL filename by using auto direction and
  LTR-isolating only the suffix so it's always on a side.
- menu.lua: handle bidi_wrap_func outside getMenuText(), which
  may be used in other contexts.
- Add BD.filepath() and BD.dirpath()

frontend/ui/bidi.lua

@@ -37,6 +37,7 @@ https://material.io/design/usability/bidirectionality.html
 ]]
 
 local Language = require("ui/language")
+local util = require("util")
 local _ = require("gettext")
 
 local Bidi = {
@@ -78,13 +79,25 @@ function Bidi.setup(lang)
             xtext.setDefaultLang(alt_lang)
         end
     end
-    -- Optimise Bidi.default and Bidi.wrap by aliasing them to the right wrappers
+    -- Optimise some wrappers by aliasing them to the right wrappers
     if Bidi._rtl_ui_text then
         Bidi.default = Bidi.rtl
         Bidi.wrap = Bidi.rtl
+        Bidi.filename = Bidi._filename_rtl
+        Bidi.filepath = Bidi.ltr -- see if we need to split and _filename_rtl() the filename part
+        Bidi.directory = Bidi.ltr
+        Bidi.dirpath = Bidi.ltr
+        Bidi.path = Bidi.ltr
+        Bidi.url = Bidi.ltr
     else
         Bidi.default = Bidi.ltr
-        Bidi.wrap = Bidi.noop
+        Bidi.wrap = Bidi.nowrap
+        Bidi.filename = Bidi.nowrap
+        Bidi.filepath = Bidi.nowrap
+        Bidi.directory = Bidi.nowrap
+        Bidi.dirpath = Bidi.nowrap
+        Bidi.path = Bidi.nowrap
+        Bidi.url = Bidi.nowrap
     end
 end
 
@@ -160,14 +173,14 @@ function Bidi.default(text) -- default direction
     return Bidi._rtl_ui_text and Bidi.rtl(text) or Bidi.ltr(text)
 end
 
-function Bidi.noop(text) -- no wrap
+function Bidi.nowrap(text)
     return text
 end
 
 -- Helper for concatenated string bits of numbers an symbols (like
 -- our reader footer) to keep them ordered in RTL UI (to not have
 -- a letter B for battery make the whole string considered LTR).
--- Note: it will be replaced and aliased to Bidi.noop or Bidi.rtl
+-- Note: it will be replaced and aliased to Bidi.nowrap or Bidi.rtl
 -- by Bibi.setup() as an optimisation
 function Bidi.wrap(text)
     return Bidi._rtl_ui_text and Bidi.rtl(text) or text
@@ -181,9 +194,21 @@ end
 -- shown as real RTL).
 -- Note: when the filename or path are standalone in a TextWidget, it's
 -- better to use "para_direction_rtl = false" without any wrapping.
-Bidi.filename = Bidi.ltr
-Bidi.directory = Bidi.ltr
-Bidi.path = Bidi.ltr
-Bidi.url = Bidi.ltr
+Bidi.filename = Bidi.nowrap  -- aliased to Bidi._filename_rtl if _rtl_ui_text
+Bidi.filepath = Bidi.nowrap  -- aliased to Bidi.ltr if _rtl_ui_text
+Bidi.directory = Bidi.nowrap -- aliased to Bidi.ltr if _rtl_ui_text
+Bidi.dirpath = Bidi.nowrap   -- aliased to Bidi.ltr if _rtl_ui_text
+Bidi.path = Bidi.nowrap      -- aliased to Bidi.ltr if _rtl_ui_text
+Bidi.url = Bidi.nowrap       -- aliased to Bidi.ltr if _rtl_ui_text
+
+function Bidi._filename_rtl(filename)
+    -- We always want to show the extension either on the left
+    -- or on the right - never in the middle (which could happen
+    -- with the bidi algo if we give it the filename as-is).
+    local name, suffix = util.splitFileNameSuffix(filename)
+    -- Let the first strong character of the filename decides
+    -- about the direction
+    return Bidi.auto(name .. "." .. Bidi.ltr(suffix))
+end
 
 return Bidi

frontend/ui/widget/menu.lua

@@ -135,6 +135,7 @@ Widget that displays an item for menu
 --]]
 local MenuItem = InputContainer:new{
     text = nil,
+    bidi_wrap_func = nil,
     show_parent = nil,
     detail = nil,
     font = "cfont",
@@ -257,6 +258,12 @@ function MenuItem:init()
     -- get rid of any \n (which could be found in highlighted text in bookmarks).
     local text = self.text:gsub("\n", " ")
 
+    -- Wrap text with provided bidi_wrap_func (only provided by FileChooser,
+    -- to correctly display filenames and directories)
+    if self.bidi_wrap_func then
+        text = self.bidi_wrap_func(text)
+    end
+
     if self.single_line then  -- items only in single line
         -- No font size change: text will be truncated if it overflows
         item_name = TextWidget:new{
@@ -1002,6 +1009,7 @@ function Menu:updateItems(select_number)
                 state = self.item_table[i].state,
                 state_size = self.state_size or {},
                 text = Menu.getMenuText(self.item_table[i]),
+                bidi_wrap_func = self.item_table[i].bidi_wrap_func,
                 mandatory = self.item_table[i].mandatory,
                 bold = self.item_table.current == i or self.item_table[i].bold == true,
                 dim = self.item_table[i].dim,
@@ -1308,9 +1316,6 @@ function Menu.getMenuText(item)
     else
         text = item.text
     end
-    if item.bidi_wrap_func then
-        text = item.bidi_wrap_func(text)
-    end
     if item.sub_item_table ~= nil or item.sub_item_table_func then
         text = string.format(sub_item_format, text)
     end