HackStudio: Do not create a new LanguageClient unless needed

Previously, whenever Editor::set_document() was called, we destroyed
the previous LanguageClient instance of the editor and created a new
one.

We now check if the language of the existing LanguageClient matches the
new document, and if so we do not create a new LanguageClient instance.

This fixes an issue where doing "goto definition" would crash
HackStudio. This was probably introduced in 44418cb.

The crash occurred because when doing "goto definition", we called a
AK::Function callback from the LanguageClient, which internally called
Editor::set_document().

Editor::set_document() destroyed the existing LanguageClient, which
cased a VERIFY in Function::clear() to fail because we were trying to
destroy the AK::Function object while executing inside it.

Userland/DevTools/HackStudio/Editor.cpp

@@ -440,33 +440,18 @@ CodeDocument& Editor::code_document()
 
 void Editor::set_document(GUI::TextDocument& doc)
 {
+ if (has_document() && &document() == &doc)
+ return;
+
  VERIFY(doc.is_code_document());
  GUI::TextEditor::set_document(doc);
 
  set_override_cursor(Gfx::StandardCursor::IBeam);
 
- CodeDocument& code_document = static_cast<CodeDocument&>(doc);
- switch (code_document.language()) {
- case Language::Cpp:
- set_syntax_highlighter(make<Cpp::SyntaxHighlighter>());
- m_language_client = get_language_client<LanguageClients::Cpp::ServerConnection>(project().root_path());
- break;
- case Language::GML:
- set_syntax_highlighter(make<GUI::GMLSyntaxHighlighter>());
- break;
- case Language::JavaScript:
- set_syntax_highlighter(make<JS::SyntaxHighlighter>());
- break;
- case Language::Ini:
- set_syntax_highlighter(make<GUI::IniSyntaxHighlighter>());
- break;
- case Language::Shell:
- set_syntax_highlighter(make<Shell::SyntaxHighlighter>());
- m_language_client = get_language_client<LanguageClients::Shell::ServerConnection>(project().root_path());
- break;
- default:
- set_syntax_highlighter({});
- }
+ auto& code_document = static_cast<CodeDocument&>(doc);
+
+ set_syntax_highlighter_for(code_document);
+ set_language_client_for(code_document);
 
  if (m_language_client) {
  set_autocomplete_provider(make<LanguageServerAidedAutocompleteProvider>(*m_language_client));
@@ -586,4 +571,39 @@ void Editor::set_cursor(const GUI::TextPosition& a_position)
  TextEditor::set_cursor(a_position);
 }
 
+void Editor::set_syntax_highlighter_for(const CodeDocument& document)
+{
+ switch (document.language()) {
+ case Language::Cpp:
+ set_syntax_highlighter(make<Cpp::SyntaxHighlighter>());
+ break;
+ case Language::GML:
+ set_syntax_highlighter(make<GUI::GMLSyntaxHighlighter>());
+ break;
+ case Language::JavaScript:
+ set_syntax_highlighter(make<JS::SyntaxHighlighter>());
+ break;
+ case Language::Ini:
+ set_syntax_highlighter(make<GUI::IniSyntaxHighlighter>());
+ break;
+ case Language::Shell:
+ set_syntax_highlighter(make<Shell::SyntaxHighlighter>());
+ break;
+ default:
+ set_syntax_highlighter({});
+ }
+}
+
+void Editor::set_language_client_for(const CodeDocument& document)
+{
+ if (m_language_client && m_language_client->language() == document.language())
+ return;
+
+ if (document.language() == Language::Cpp)
+ m_language_client = get_language_client<LanguageClients::Cpp::ServerConnection>(project().root_path());
+
+ if (document.language() == Language::Shell)
+ m_language_client = get_language_client<LanguageClients::Shell::ServerConnection>(project().root_path());
+}
+
 }

Userland/DevTools/HackStudio/Editor.h

@@ -92,6 +92,8 @@ class Editor final : public GUI::TextEditor {
  Optional<AutoCompleteRequestData> get_autocomplete_request_data();
 
  void flush_file_content_to_langauge_server();
+ void set_syntax_highlighter_for(const CodeDocument&);
+ void set_language_client_for(const CodeDocument&);
 
  explicit Editor();