LanguageServers/Cpp: Add 'FindDeclaration' capability

The C++ LanguageServer can now find the matching declaration for
variable names, function calls, struct/class types and properties.

When clicking on one of the above with Ctrl pressed, HackStudio will
ask the language server to find a matching declaration, and navigate
to the result in the Editor. :^)

Userland/DevTools/HackStudio/Editor.cpp

@@ -1,5 +1,6 @@
 /*
  * Copyright (c) 2018-2021, Andreas Kling <kling@serenityos.org>
+ * 2018-2021, the SerenityOS developers
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -153,9 +154,7 @@ void Editor::show_documentation_tooltip_if_available(const String& hovered_token
 {
     auto it = man_paths().find(hovered_token);
     if (it == man_paths().end()) {
-#if EDITOR_DEBUG
+        dbgln_if(EDITOR_DEBUG, "no man path for {}", hovered_token);
-        dbgln("no man path for {}", hovered_token);
-#endif
         m_documentation_tooltip_window->hide();
         return;
     }
@@ -164,9 +163,7 @@ void Editor::show_documentation_tooltip_if_available(const String& hovered_token
         return;
     }
 
-#if EDITOR_DEBUG
+    dbgln(EDITOR_DEBUG, "opening {}", it->value);
-    dbgln("opening {}", it->value);
-#endif
     auto file = Core::File::construct(it->value);
     if (!file->open(Core::File::ReadOnly)) {
         dbgln("failed to open {}, {}", it->value, file->error_string());
@@ -236,9 +233,7 @@ void Editor::mousemove_event(GUI::MouseEvent& event)
             auto end_line_length = document().line(span.range.end().line()).length();
             adjusted_range.end().set_column(min(end_line_length, adjusted_range.end().column() + 1));
             auto hovered_span_text = document().text_in_range(adjusted_range);
-#if EDITOR_DEBUG
+            dbgln_if(EDITOR_DEBUG, "Hovering: {} \"{}\"", adjusted_range, hovered_span_text);
-            dbgln("Hovering: {} \"{}\"", adjusted_range, hovered_span_text);
-#endif
 
             if (is_clickable) {
                 is_over_clickable = true;
@@ -298,6 +293,10 @@ void Editor::mousedown_event(GUI::MouseEvent& event)
             on_navigatable_link_click(*span);
             return;
         }
+        if (highlighter->is_identifier(span->data)) {
+            on_identifier_click(*span);
+            return;
+        }
     }
 
     GUI::TextEditor::mousedown_event(event);
@@ -325,9 +324,7 @@ static HashMap<String, String>& include_paths()
             auto path = it.next_full_path();
             if (!Core::File::is_directory(path)) {
                 auto key = path.substring(base.length() + 1, path.length() - base.length() - 1);
-#if EDITOR_DEBUG
+                dbgln_if(EDITOR_DEBUG, "Adding header \"{}\" in path \"{}\"", key, path);
-                dbgln("Adding header \"{}\" in path \"{}\"", key, path);
-#endif
                 paths.set(key, path);
             } else {
                 handle_directory(base, path, handle_directory);
@@ -349,9 +346,7 @@ void Editor::navigate_to_include_if_available(String path)
 {
     auto it = include_paths().find(path);
     if (it == include_paths().end()) {
-#if EDITOR_DEBUG
+        dbgln_if(EDITOR_DEBUG, "no header {} found.", path);
-        dbgln("no header {} found.", path);
-#endif
         return;
     }
 
@@ -523,9 +518,23 @@ void Editor::on_navigatable_link_click(const GUI::TextDocumentSpan& span)
     adjusted_range.end().set_column(adjusted_range.end().column() + 1);
     auto span_text = document().text_in_range(adjusted_range);
     auto header_path = span_text.substring(1, span_text.length() - 2);
-#if EDITOR_DEBUG
+    dbgln_if(EDITOR_DEBUG, "Ctrl+click: {} \"{}\"", adjusted_range, header_path);
-    dbgln("Ctrl+click: {} \"{}\"", adjusted_range, header_path);
-#endif
     navigate_to_include_if_available(header_path);
 }
+
+void Editor::open_and_set_cursor(const String& file, size_t line, size_t column)
+{
+    if (code_document().file_path() != file)
+        on_open(file);
+    set_cursor(GUI::TextPosition { line, column });
+}
+
+void Editor::on_identifier_click(const GUI::TextDocumentSpan& span)
+{
+    m_language_client->on_declaration_found = [this](const String& file, size_t line, size_t column) {
+        open_and_set_cursor(file, line, column);
+    };
+    m_language_client->search_declaration(code_document().file_path(), span.range.start().line(), span.range.start().column());
+}
+
 }

Userland/DevTools/HackStudio/Editor.h

@@ -1,5 +1,6 @@
 /*
  * Copyright (c) 2018-2021, Andreas Kling <kling@serenityos.org>
+ * 2018-2021, the SerenityOS developers
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -77,6 +78,8 @@ private:
     void show_documentation_tooltip_if_available(const String&, const Gfx::IntPoint& screen_location);
     void navigate_to_include_if_available(String);
     void on_navigatable_link_click(const GUI::TextDocumentSpan&);
+    void on_identifier_click(const GUI::TextDocumentSpan&);
+    void open_and_set_cursor(const String& file, size_t line, size_t column);
 
     Gfx::IntRect breakpoint_icon_rect(size_t line_number) const;
     static const Gfx::Bitmap& breakpoint_icon_bitmap();

Userland/DevTools/HackStudio/LanguageClient.cpp

@@ -40,6 +40,14 @@ void ServerConnection::handle(const Messages::LanguageClient::AutoCompleteSugges
     }
     m_language_client->provide_autocomplete_suggestions(message.suggestions());
 }
+void ServerConnection::handle(const Messages::LanguageClient::DeclarationLocation& message)
+{
+    if (!m_language_client) {
+        dbgln("Language Server connection has no attached language client");
+        return;
+    }
+    m_language_client->declaration_found(message.file_name(), message.line(), message.column());
+}
 
 void ServerConnection::die()
 {
@@ -87,8 +95,6 @@ void LanguageClient::request_autocomplete(const String& path, size_t cursor_line
 
 void LanguageClient::provide_autocomplete_suggestions(const Vector<GUI::AutocompleteProvider::Entry>& suggestions)
 {
-    if (!m_server_connection)
-        return;
     if (on_autocomplete_suggestions)
         on_autocomplete_suggestions(suggestions);
 
@@ -147,4 +153,22 @@ void ServerConnection::remove_instance_for_project(const String& project_path)
     s_instances_for_projects.remove(key);
 }
 
+void LanguageClient::search_declaration(const String& path, size_t line, size_t column)
+{
+    if (!m_server_connection)
+        return;
+    set_active_client();
+    m_server_connection->post_message(Messages::LanguageServer::FindDeclaration(path, line, column));
+}
+
+void LanguageClient::declaration_found(const String& file, size_t line, size_t column)
+{
+    if (!on_declaration_found) {
+        dbgln("on_declaration_found callback is not set");
+        return;
+    }
+    dbgln("calling on_declaration_found");
+    on_declaration_found(file, line, column);
+}
+
 }

Userland/DevTools/HackStudio/LanguageClient.h

@@ -90,6 +90,7 @@ public:
 
 protected:
     virtual void handle(const Messages::LanguageClient::AutoCompleteSuggestions&) override;
+    virtual void handle(const Messages::LanguageClient::DeclarationLocation&) override;
 
     String m_project_path;
     WeakPtr<LanguageClient> m_language_client;
@@ -123,11 +124,14 @@ public:
     virtual void remove_text(const String& path, size_t from_line, size_t from_column, size_t to_line, size_t to_column);
     virtual void request_autocomplete(const String& path, size_t cursor_line, size_t cursor_column);
     virtual void set_autocomplete_mode(const String& mode);
+    virtual void search_declaration(const String& path, size_t line, size_t column);
 
     void provide_autocomplete_suggestions(const Vector<GUI::AutocompleteProvider::Entry>&);
+    void declaration_found(const String& file, size_t line, size_t column);
     void on_server_crash();
 
     Function<void(Vector<GUI::AutocompleteProvider::Entry>)> on_autocomplete_suggestions;
+    Function<void(const String&, size_t, size_t)> on_declaration_found;
 
 private:
     WeakPtr<ServerConnection> m_server_connection;

Userland/DevTools/HackStudio/LanguageServers/Cpp/AutoCompleteEngine.h

@@ -41,6 +41,13 @@ public:
     virtual void on_edit([[maybe_unused]] const String& file) {};
     virtual void file_opened([[maybe_unused]] const String& file) {};
 
+    struct ProjectPosition {
+        String file;
+        size_t line;
+        size_t column;
+    };
+    virtual Optional<ProjectPosition> find_declaration_of(const String&, const GUI::TextPosition&) { return {}; };
+
 protected:
     const FileDB& filedb() const { return m_filedb; }
 

Userland/DevTools/HackStudio/LanguageServers/Cpp/ClientConnection.cpp

@@ -128,7 +128,7 @@ void ClientConnection::handle(const Messages::LanguageServer::SetFileContent& me
 
 void ClientConnection::handle(const Messages::LanguageServer::SetAutoCompleteMode& message)
 {
-#ifdef DEBUG_CPP_LANGUAGE_SERVER
+#ifdef CPP_LANGUAGE_SERVER_DEBUG
     dbgln("SetAutoCompleteMode: {}", message.mode());
 #endif
     if (message.mode() == "Parser")
@@ -137,4 +137,23 @@ void ClientConnection::handle(const Messages::LanguageServer::SetAutoCompleteMod
         m_autocomplete_engine = make<LexerAutoComplete>(m_filedb);
 }
 
+void ClientConnection::handle(const Messages::LanguageServer::FindDeclaration& message)
+{
+    dbgln_if(CPP_LANGUAGE_SERVER_DEBUG, "FindDeclaration: {} {}:{}", message.file_name(), message.line(), message.column());
+    auto document = m_filedb.get(message.file_name());
+    if (!document) {
+        dbgln("file {} has not been opened", message.file_name());
+        return;
+    }
+
+    GUI::TextPosition identifier_position = { (size_t)message.line(), (size_t)message.column() };
+    auto location = m_autocomplete_engine->find_declaration_of(message.file_name(), identifier_position);
+    if (!location.has_value()) {
+        dbgln("could not find declaration");
+        return;
+    }
+    dbgln_if(CPP_LANGUAGE_SERVER_DEBUG, "declaration location: {} {}:{}", location.value().file, location.value().line, location.value().column);
+    post_message(Messages::LanguageClient::DeclarationLocation(location.value().file, location.value().line, location.value().column));
+}
+
 }

Userland/DevTools/HackStudio/LanguageServers/Cpp/ClientConnection.h

@@ -57,6 +57,7 @@ private:
     virtual void handle(const Messages::LanguageServer::SetFileContent&) override;
     virtual void handle(const Messages::LanguageServer::AutoCompleteSuggestions&) override;
     virtual void handle(const Messages::LanguageServer::SetAutoCompleteMode&) override;
+    virtual void handle(const Messages::LanguageServer::FindDeclaration&) override;
 
     FileDB m_filedb;
     OwnPtr<AutoCompleteEngine> m_autocomplete_engine;

Userland/DevTools/HackStudio/LanguageServers/Cpp/ParserAutoComplete.cpp

@@ -33,16 +33,6 @@
 #include <LibCpp/Preprocessor.h>
 #include <LibRegex/Regex.h>
 
-// #define AUTOCOMPLETE_VERBOSE
-
-#ifdef AUTOCOMPLETE_VERBOSE
-#    define VERBOSE(fmt, ...) dbgln(fmt, ##__VA_ARGS__)
-#else
-#    define VERBOSE(fmt, ...) \
-        do {                  \
-        } while (0)
-#endif
-
 namespace LanguageServers::Cpp {
 
 ParserAutoComplete::ParserAutoComplete(const FileDB& filedb)
@@ -77,7 +67,7 @@ OwnPtr<ParserAutoComplete::DocumentData> ParserAutoComplete::create_document_dat
     for (auto& path : document_data->preprocessor.included_paths()) {
         get_or_create_document_data(document_path_from_include_path(path));
     }
-#ifdef DEBUG_AUTOCOMPLETE
+#ifdef CPP_LANGUAGE_SERVER_DEBUG
     root->dump(0);
 #endif
     return move(document_data);
@@ -99,12 +89,12 @@ Vector<GUI::AutocompleteProvider::Entry> ParserAutoComplete::get_suggestions(con
 {
     Cpp::Position position { autocomplete_position.line(), autocomplete_position.column() > 0 ? autocomplete_position.column() - 1 : 0 };
 
-    VERBOSE("ParserAutoComplete position {}:{}", position.line, position.column);
+    dbgln_if(CPP_LANGUAGE_SERVER_DEBUG, "ParserAutoComplete position {}:{}", position.line, position.column);
 
     const auto& document = get_or_create_document_data(file);
     auto node = document.parser.node_at(position);
     if (!node) {
-        VERBOSE("no node at position {}:{}", position.line, position.column);
+        dbgln_if(CPP_LANGUAGE_SERVER_DEBUG, "no node at position {}:{}", position.line, position.column);
         return {};
     }
 
@@ -130,17 +120,22 @@ Vector<GUI::AutocompleteProvider::Entry> ParserAutoComplete::get_suggestions(con
     return autocomplete_name(document, *node, partial_text.view());
 }
 
-Vector<GUI::AutocompleteProvider::Entry> ParserAutoComplete::autocomplete_name(const DocumentData& document, const ASTNode& node, const StringView& partial_text) const
+NonnullRefPtrVector<Declaration> ParserAutoComplete::get_available_declarations(const DocumentData& document, const ASTNode& node) const
 {
     const Cpp::ASTNode* current = &node;
-    NonnullRefPtrVector<Cpp::Declaration> available_declarations;
+    NonnullRefPtrVector<Declaration> available_declarations;
     while (current) {
         available_declarations.append(current->declarations());
         current = current->parent();
     }
 
     available_declarations.append(get_declarations_in_outer_scope_including_headers(document));
+    return available_declarations;
+}
 
+Vector<GUI::AutocompleteProvider::Entry> ParserAutoComplete::autocomplete_name(const DocumentData& document, const ASTNode& node, const StringView& partial_text) const
+{
+    auto available_declarations = get_available_declarations(document, node);
     Vector<StringView> available_names;
     auto add_name = [&available_names](auto& name) {
         if (name.is_null() || name.is_empty())
@@ -173,7 +168,7 @@ Vector<GUI::AutocompleteProvider::Entry> ParserAutoComplete::autocomplete_proper
 {
     auto type = type_of(document, *parent.m_object);
     if (type.is_null()) {
-        VERBOSE("Could not infer type of object");
+        dbgln_if(CPP_LANGUAGE_SERVER_DEBUG, "Could not infer type of object");
         return {};
     }
 
@@ -321,4 +316,47 @@ void ParserAutoComplete::file_opened([[maybe_unused]] const String& file)
     set_document_data(file, create_document_data_for(file));
 }
 
+Optional<AutoCompleteEngine::ProjectPosition> ParserAutoComplete::find_declaration_of(const String& file_name, const GUI::TextPosition& identifier_position)
+{
+    const auto& document = get_or_create_document_data(file_name);
+    auto node = document.parser.node_at(Cpp::Position { identifier_position.line(), identifier_position.column() });
+    if (!node) {
+        dbgln_if(CPP_LANGUAGE_SERVER_DEBUG, "no node at position {}:{}", identifier_position.line(), identifier_position.column());
+        return {};
+    }
+    auto decl = find_declaration_of(document, *node);
+    if (!decl)
+        return {};
+
+    return ProjectPosition { decl->filename(), decl->start().line, decl->start().column };
+}
+
+RefPtr<Declaration> ParserAutoComplete::find_declaration_of(const DocumentData& document_data, const ASTNode& node) const
+{
+    dbgln_if(CPP_LANGUAGE_SERVER_DEBUG, "find_declaration_of: {}", document_data.parser.text_of_node(node));
+    auto declarations = get_available_declarations(document_data, node);
+    for (auto& decl : declarations) {
+        if (node.is_identifier() && decl.is_variable_or_parameter_declaration()) {
+            if (((Cpp::VariableOrParameterDeclaration&)decl).m_name == static_cast<const Identifier&>(node).m_name)
+                return decl;
+        }
+        if (node.is_type() && decl.is_struct_or_class()) {
+            if (((Cpp::StructOrClassDeclaration&)decl).m_name == static_cast<const Type&>(node).m_name)
+                return decl;
+        }
+        if (node.is_function_call() && decl.is_function()) {
+            if (((Cpp::FunctionDeclaration&)decl).m_name == static_cast<const FunctionCall&>(node).m_name)
+                return decl;
+        }
+        if (is_property(node) && decl.is_struct_or_class()) {
+            for (auto& member : ((Cpp::StructOrClassDeclaration&)decl).m_members) {
+                ASSERT(node.is_identifier());
+                if (member.m_name == ((const Identifier&)node).m_name)
+                    return member;
+            }
+        }
+    }
+    return {};
+}
+
 }

Userland/DevTools/HackStudio/LanguageServers/Cpp/ParserAutoComplete.h

@@ -47,10 +47,11 @@ public:
     virtual Vector<GUI::AutocompleteProvider::Entry> get_suggestions(const String& file, const GUI::TextPosition& autocomplete_position) override;
     virtual void on_edit(const String& file) override;
     virtual void file_opened([[maybe_unused]] const String& file) override;
+    virtual Optional<ProjectPosition> find_declaration_of(const String& file_name, const GUI::TextPosition& identifier_position) override;
 
 private:
     struct DocumentData {
-        DocumentData(String&& text);
+        DocumentData(String&& text, const String& filename);
         String text;
         Preprocessor preprocessor;
         Parser parser;
@@ -63,6 +64,8 @@ private:
     String type_of_variable(const Identifier&) const;
     bool is_property(const ASTNode&) const;
     bool is_empty_property(const DocumentData&, const ASTNode&, const Position& autocomplete_position) const;
+    RefPtr<Declaration> find_declaration_of(const DocumentData&, const ASTNode&) const;
+    NonnullRefPtrVector<Declaration> get_available_declarations(const DocumentData&, const ASTNode&) const;
 
     struct PropertyInfo {
         StringView name;

Userland/DevTools/HackStudio/LanguageServers/LanguageClient.ipc

@@ -1,4 +1,5 @@
 endpoint LanguageClient = 8002
 {
     AutoCompleteSuggestions(Vector<GUI::AutocompleteProvider::Entry> suggestions) =|
+    DeclarationLocation(String file_name, i32 line, i32 column) =|
 }

Userland/DevTools/HackStudio/LanguageServers/LanguageServer.ipc

@@ -9,4 +9,6 @@ endpoint LanguageServer = 8001
 
     AutoCompleteSuggestions(String file_name, i32 cursor_line, i32 cursor_column) =|
     SetAutoCompleteMode(String mode) =|
+    FindDeclaration(String file_name, i32 line, i32 column) =|
+
 }

Userland/DevTools/HackStudio/LanguageServers/Shell/ClientConnection.h

@@ -57,6 +57,7 @@ private:
     virtual void handle(const Messages::LanguageServer::SetFileContent&) override;
     virtual void handle(const Messages::LanguageServer::AutoCompleteSuggestions&) override;
     virtual void handle(const Messages::LanguageServer::SetAutoCompleteMode&) override { }
+    virtual void handle(const Messages::LanguageServer::FindDeclaration&) override {};
 
     RefPtr<GUI::TextDocument> document_for(const String& file_name);