textDocument/documentSymbol: support unopened files (#548)

src/message_handler.cc

@@ -252,9 +252,9 @@ QueryFile *MessageHandler::findFile(const std::string &path, int *out_file_id) {
 
 std::pair<QueryFile *, WorkingFile *>
 MessageHandler::findOrFail(const std::string &path, ReplyOnce &reply,
-                           int *out_file_id) {
+                           int *out_file_id, bool allow_unopened) {
   WorkingFile *wf = wfiles->getFile(path);
-  if (!wf) {
+  if (!wf && !allow_unopened) {
     reply.notOpened(path);
     return {nullptr, nullptr};
   }

src/message_handler.hh

@@ -236,7 +236,8 @@ struct MessageHandler {
   QueryFile *findFile(const std::string &path, int *out_file_id = nullptr);
   std::pair<QueryFile *, WorkingFile *> findOrFail(const std::string &path,
                                                    ReplyOnce &reply,
-                                                   int *out_file_id = nullptr);
+                                                   int *out_file_id = nullptr,
+                                                   bool allow_unopened = false);
 
 private:
   void bind(const char *method, void (MessageHandler::*handler)(JsonReader &));

src/messages/textDocument_document.cc

@@ -147,8 +147,8 @@ void MessageHandler::textDocument_documentSymbol(JsonReader &reader,
 
   int file_id;
   auto [file, wf] =
-      findOrFail(param.textDocument.uri.getPath(), reply, &file_id);
-  if (!wf)
+      findOrFail(param.textDocument.uri.getPath(), reply, &file_id, true);
+  if (!file)
     return;
   auto allows = [&](SymbolRef sym) { return !(sym.role & param.excludeRole); };