cleanup: remove dead code, fix bugs, refactor SSH dest parsing

- Remove debug printf calls from file.c
- Remove dead code: chunk_print, chunk_format, chunk_data_create/delete
- Remove unused config.use_single_send_per_file field
- Fix server_delete() no-op (double-pointer)
- Fix double cast (long)(long) -> ptrdiff_t in chunk.c
- Fix thread return value: thrd_error instead of 1
- Remove unused config param from receive_chunk_enqueue()
- Make queue_double_capacity() static
- Move SSH dest parsing into config.c as config_parse_ssh_dest()
- Fix test_config_ssh_dest to test parsing round-trip
- Remove chunk_format test (obsolete format)
- Replace chunk_data_delete with data_destroy in tests

src/client/client.c

@@ -125,7 +125,7 @@ int send_chunks_multithreaded(void *pipeline_context) {
       int ok = receive_status(client->file_descriptor) == STATUS_OK;
       client_disconnect(client);
       client_delete(client);
-      return ok ? thrd_success : 1;
+      return ok ? thrd_success : thrd_error;
     }
     if (send_chunk(client, current_chunk, context->config) != 0) {
       perror("Something unexpected happend while sending the chunk");
@@ -189,16 +189,6 @@ int send_files_multithreaded(Config *config) {
   return 0;
 }
 
-static int is_remote_dest(const char *s) {
-  const char *colon = strchr(s, ':');
-  if (!colon) return 0;
-  if (colon == s) return 0;
-  for (const char *p = s; p < colon; p++) {
-    if (*p == '/') return 0;
-  }
-  return 1;
-}
-
 static void print_usage(void) {
   printf("Usage:\n");
   printf("  fastsync [options] <source> <destination>\n");
@@ -307,14 +297,7 @@ int main(int argc, char *argv[]) {
     config->receive_root_directory = str_dup(argv[positional_args[1]]);
     config->save_to_disk = true;
 
-    if (is_remote_dest(config->receive_root_directory)) {
-      config->transport = TRANSPORT_SSH;
-      config->ssh_destination = str_dup(config->receive_root_directory);
-      char *colon = strchr(config->receive_root_directory, ':');
-      char *path = str_dup(colon + 1);
-      free(config->receive_root_directory);
-      config->receive_root_directory = path;
-    }
+    config_parse_ssh_dest(config);
   } else if (positional_count == 1) {
     fprintf(stderr, "Error: missing destination argument\n");
     print_usage();