+local function atomic_store(filename, data)
+ local scratch = filename.."~";
+ local f, ok, msg;
+ repeat
+ f, msg = io_open(scratch, "w");
+ if not f then break end
+
+ ok, msg = f:write(data);
+ if not ok then break end
+
+ ok, msg = f:close();
+ if not ok then break end
+
+ return os_rename(scratch, filename);
+ until false;
+
+ -- Cleanup
+ if f then f:close(); end
+ os_remove(scratch);
+ return nil, msg;
+end
+
+if prosody and prosody.platform ~= "posix" then
+ -- os.rename does not overwrite existing files on Windows
+ -- TODO We could use Transactional NTFS on Vista and above
+ function atomic_store(filename, data)
+ local f, err = io_open(filename, "w");
+ if not f then return f, err; end
+ local ok, msg = f:write(data);
+ if not ok then f:close(); return ok, msg; end
+ return f:close();
+ end
+end
+
+local function store(username, host, datastore, data)