Cloud storage: fix sorting non-English filenames (koreader#12644)

Reported in koreader#12638.

frontend/apps/cloudstorage/dropboxapi.lua

@@ -1,13 +1,13 @@
 local DocumentRegistry = require("document/documentregistry")
 local JSON = require("json")
+local ffiUtil = require("ffi/util")
 local http = require("socket.http")
 local lfs = require("libs/libkoreader-lfs")
 local logger = require("logger")
 local ltn12 = require("ltn12")
 local socket = require("socket")
 local socketutil = require("socketutil")
 local util = require("util")
-local BaseUtil = require("ffi/util")
 local _ = require("gettext")
 
 local DropBoxApi = {
@@ -126,7 +126,7 @@ function DropBoxApi:downloadFile(path, token, local_path)
 end
 
 function DropBoxApi:uploadFile(path, token, file_path, etag, overwrite)
-    local data = "{\"path\": \"" .. path .. "/" .. BaseUtil.basename(file_path) ..
+    local data = "{\"path\": \"" .. path .. "/" .. ffiUtil.basename(file_path) ..
         "\",\"mode\":" .. (overwrite and "\"overwrite\"" or "\"add\"") ..
         ",\"autorename\": " .. (overwrite and "false" or "true") ..
         ",\"mute\": false,\"strict_conflict\": false}"
@@ -202,10 +202,10 @@ function DropBoxApi:listFolder(path, token, folder_mode)
     end
     --sort
     table.sort(dropbox_list, function(v1,v2)
-        return v1.text < v2.text
+        return ffiUtil.strcoll(v1.text, v2.text)
     end)
     table.sort(dropbox_file, function(v1,v2)
-        return v1.text < v2.text
+        return ffiUtil.strcoll(v1.text, v2.text)
     end)
     -- Add special folder.
     if folder_mode then

frontend/apps/cloudstorage/ftpapi.lua

@@ -1,4 +1,5 @@
 local DocumentRegistry = require("document/documentregistry")
+local ffiUtil = require("ffi/util")
 local ftp = require("socket.ftp")
 local ltn12 = require("ltn12")
 local util = require("util")
@@ -71,10 +72,10 @@ function FtpApi:listFolder(address_path, folder_path)
     end
     --sort
     table.sort(ftp_list, function(v1,v2)
-        return v1.text < v2.text
+        return ffiUtil.strcoll(v1.text, v2.text)
     end)
     table.sort(ftp_file, function(v1,v2)
-        return v1.text < v2.text
+        return ffiUtil.strcoll(v1.text, v2.text)
     end)
     for _, files in ipairs(ftp_file) do
         table.insert(ftp_list, {

frontend/apps/cloudstorage/webdavapi.lua

@@ -1,5 +1,5 @@
 local DocumentRegistry = require("document/documentregistry")
-local FFIUtil = require("ffi/util")
+local ffiUtil = require("ffi/util")
 local http = require("socket.http")
 local ltn12 = require("ltn12")
 local socket = require("socket")
@@ -103,7 +103,7 @@ function WebDavApi:listFolder(address, user, pass, folder_path, folder_mode)
             --logger.dbg("WebDav catalog item=", item)
             -- <d:href> is the path and filename of the entry.
             local item_fullpath = item:match("<[^:]*:href[^>]*>(.*)</[^:]*:href>")
-            local item_name = FFIUtil.basename(util.htmlEntitiesToUtf8(util.urlDecode(item_fullpath)))
+            local item_name = ffiUtil.basename(util.htmlEntitiesToUtf8(util.urlDecode(item_fullpath)))
             local is_current_dir = item_name == string.sub(folder_path, -#item_name)
             local is_not_collection = item:find("<[^:]*:resourcetype%s*/>") or
                                       item:find("<[^:]*:resourcetype></[^:]*:resourcetype>")
@@ -133,10 +133,10 @@ function WebDavApi:listFolder(address, user, pass, folder_path, folder_mode)
 
     --sort
     table.sort(webdav_list, function(v1,v2)
-        return v1.text < v2.text
+        return ffiUtil.strcoll(v1.text, v2.text)
     end)
     table.sort(webdav_file, function(v1,v2)
-        return v1.text < v2.text
+        return ffiUtil.strcoll(v1.text, v2.text)
     end)
     for _, files in ipairs(webdav_file) do
         table.insert(webdav_list, {