Index file language and send it on hover

src/command_line.cc

@@ -2328,7 +2328,9 @@ bool QueryDbMainLoop(Config* config,
           if (!ls_range)
             continue;
 
-          response.result.contents = GetHoverForSymbol(db, ref.idx);
+          response.result.contents.value = GetHoverForSymbol(db, ref.idx);
+          response.result.contents.language = file->def->language;
+
           response.result.range = *ls_range;
           break;
         }

src/indexer.cc

@@ -995,6 +995,24 @@ void indexDeclaration(CXClientData client_data, const CXIdxDeclInfo* decl) {
   if (!db)
     return;
 
+
+  // update the file language
+  // TODO: only do this when |is_first_ownership| in ConsumeFile is true
+  switch (clang_getCursorLanguage(decl->cursor)) {
+  case CXLanguage_C:
+    db->language = "c";
+    break;
+  case CXLanguage_CPlusPlus:
+    db->language = "c++";
+    break;
+  case CXLanguage_ObjC:
+    db->language = "objc";
+    break;
+  case CXLanguage_Invalid:
+    db->language = "invalid";
+    break;
+  }
+
   NamespaceHelper* ns = &param->ns;
 
   // std::cerr << "DECL kind=" << decl->entityInfo->kind << " at " <<

src/indexer.h

@@ -473,6 +473,8 @@ struct IndexFile {
   std::string path;
   std::vector<std::string> args;
   int64_t last_modification_time = 0;
+  // "c++", "c", "obj-c", "invalid" or "unknown"
+  std::string language;
 
   // The path to the translation unit cc file which caused the creation of this
   // IndexFile. When parsing a translation unit we generate many IndexFile

src/language_server_api.h

@@ -1179,6 +1179,24 @@ MAKE_REFLECT_STRUCT(lsSignatureHelp,
                     signatures,
                     activeSignature,
                     activeParameter);
+
+// MarkedString can be used to render human readable text. It is either a markdown string
+// or a code-block that provides a language and a code snippet. The language identifier
+// is sematically equal to the optional language identifier in fenced code blocks in GitHub
+// issues. See https://help.github.com/articles/creating-and-highlighting-code-blocks/#syntax-highlighting
+//
+// The pair of a language and a value is an equivalent to markdown:
+// ```${language}
+// ${value}
+// ```
+//
+// Note that markdown strings will be sanitized - that means html will be escaped.
+struct lsMarkedString {
+  std::string language;
+  std::string value;
+};
+MAKE_REFLECT_STRUCT(lsMarkedString, language, value);
+
 struct Out_TextDocumentSignatureHelp
     : public lsOutMessage<Out_TextDocumentSignatureHelp> {
   lsRequestId id;
@@ -1228,7 +1246,7 @@ struct Ipc_TextDocumentHover : public IpcMessage<Ipc_TextDocumentHover> {
 MAKE_REFLECT_STRUCT(Ipc_TextDocumentHover, id, params);
 struct Out_TextDocumentHover : public lsOutMessage<Out_TextDocumentHover> {
   struct Result {
-    std::string contents;
+    lsMarkedString contents;
     optional<lsRange> range;
   };
 

src/query.cc

@@ -171,6 +171,7 @@ void CompareGroups(std::vector<T>& previous_data,
 QueryFile::Def BuildFileDef(const IdMap& id_map, const IndexFile& indexed) {
   QueryFile::Def def;
   def.path = indexed.path;
+  def.language = indexed.language;
   def.includes = indexed.includes;
   def.inactive_regions = indexed.skipped_by_preprocessor;
 

src/query.h

@@ -169,6 +169,8 @@ void Reflect(TVisitor& visitor, MergeableUpdate<TId, TValue>& value) {
 struct QueryFile {
   struct Def {
     std::string path;
+    // Language identifier
+    std::string language;
     // Includes in the file.
     std::vector<IndexInclude> includes;
     // Outline of the file (ie, for code lens).
@@ -191,6 +193,7 @@ struct QueryFile {
 };
 MAKE_REFLECT_STRUCT(QueryFile::Def,
                     path,
+                    language,
                     outline,
                     all_symbols,
                     inactive_regions);

src/serializer.cc

@@ -169,6 +169,7 @@ void Reflect(TVisitor& visitor, IndexFile& value) {
   if (!gTestOutputMode) {
     REFLECT_MEMBER(version);
     REFLECT_MEMBER(last_modification_time);
+    REFLECT_MEMBER(language);
     REFLECT_MEMBER(import_file);
     REFLECT_MEMBER(args);
   }