Automatically detect whether colon can be used in a directory name.

telegram-bot-api/Client.cpp

@@ -3456,13 +3456,13 @@ void Client::start_up() {
   set_tag(bot_token_id_);
 
   auto suff = bot_token_with_dc_ + TD_DIR_SLASH;
-#if TD_PORT_WINDOWS
+  if (!parameters_->allow_colon_in_filenames_) {
     for (auto &c : suff) {
       if (c == ':') {
         c = '~';
       }
     }
-#endif
+  }
   dir_ = parameters_->working_directory_ + suff;
 
   class TdCallback : public td::TdCallback {

telegram-bot-api/ClientParameters.h

@@ -55,6 +55,7 @@ struct SharedData {
 
 struct ClientParameters {
   td::string working_directory_;
+  bool allow_colon_in_filenames_ = true;
 
   bool local_mode_ = false;
 

telegram-bot-api/telegram-bot-api.cpp

@@ -382,6 +382,17 @@ int main(int argc, char *argv[]) {
       }
       r_temp_file.ok_ref().first.close();
       td::unlink(r_temp_file.ok().second).ensure();
+
+      auto r_temp_dir = td::mkdtemp(working_directory, "1:a");
+      if (r_temp_dir.is_error()) {
+        parameters->allow_colon_in_filenames_ = false;
+        r_temp_dir = td::mkdtemp(working_directory, "1~a");
+        if (r_temp_dir.is_error()) {
+          return td::Status::Error(PSLICE() << "Can't create directories in the directory \"" << working_directory
+                                            << "\". Use --dir option to specify a writable working directory");
+        }
+      }
+      td::rmdir(r_temp_dir.ok()).ensure();
     }
 
     if (!temporary_directory.empty()) {