Wikpedia EPUBs: fix failure saving some files

Since 8815cbe0 and getSafeFilename() taking additional
parameters, and :gsub() returning multiple values,
filesystem type wasn't really checked and replacements
were not ensured, so saving articles like "Portal:Stuff"
failed on VFAT devices as ':' wasn't replaced.

frontend/apps/reader/modules/readerlink.lua

@@ -641,13 +641,14 @@ function ReaderLink:onGoToExternalLink(link_url)
         -- wikipedia page saved as epub, full of wikipedia links, it's
         -- too easy to click on links when wanting to change page...)
         -- But first check if this wikipedia article has been saved as EPUB
-        local epub_filename = util.getSafeFilename(wiki_page:gsub("_", " ")) .. "."..string.upper(wiki_lang)..".epub"
+        local epub_filename = wiki_page .. "."..string.upper(wiki_lang)..".epub"
         local epub_fullpath
         -- either in current book directory
         local last_file = G_reader_settings:readSetting("lastfile")
         if last_file then
             local current_book_dir = last_file:match("(.*)/")
-            local epub_path = current_book_dir .. "/" .. epub_filename
+            local safe_filename = util.getSafeFilename(epub_filename, current_book_dir):gsub("_", " ")
+            local epub_path = current_book_dir .. "/" .. safe_filename
             if util.pathExists(epub_path) then
                 epub_fullpath = epub_path
             end
@@ -658,7 +659,8 @@ function ReaderLink:onGoToExternalLink(link_url)
             if not dir then dir = G_reader_settings:readSetting("home_dir") end
             if not dir then dir = require("apps/filemanager/filemanagerutil").getDefaultDir() end
             if dir then
-                local epub_path = dir .. "/" .. epub_filename
+                local safe_filename = util.getSafeFilename(epub_filename, dir):gsub("_", " ")
+                local epub_path = dir .. "/" .. safe_filename
                 if util.pathExists(epub_path) then
                     epub_fullpath = epub_path
                 end

frontend/ui/widget/dictquicklookup.lua

@@ -355,10 +355,6 @@ function DictQuickLookup:update()
                         -- if forced_lang was specified, it may not be in our wiki_languages,
                         -- but ReaderWikipedia will have put it in result.lang
                         local lang = self.lang or self.wiki_languages_copy[1]
-                        -- Just to be safe (none of the invalid chars, except ':' for uninteresting
-                        -- Portal: or File: wikipedia pages, should be in lookup_word)
-                        local cleaned_lookupword = util.getSafeFilename(self.lookupword:gsub("_", " "))
-                        local filename = cleaned_lookupword .. "."..string.upper(lang)..".epub"
                         -- Find a directory to save file into
                         local dir
                         if G_reader_settings:isTrue("wikipedia_save_in_book_dir") and not self:isDocless() then
@@ -376,6 +372,10 @@ function DictQuickLookup:update()
                             })
                             return
                         end
+                        -- Just to be safe (none of the invalid chars, except ':' for uninteresting
+                        -- Portal: or File: wikipedia pages, should be in lookupword)
+                        local filename = self.lookupword .. "."..string.upper(lang)..".epub"
+                        filename = util.getSafeFilename(filename, dir):gsub("_", " ")
                         local epub_path = dir .. "/" .. filename
                         UIManager:show(ConfirmBox:new{
                             text = T(_("Save as %1?"), BD.filename(filename)),