HackStudio: Add C++ Language Server

The language server keeps track of the content of currently edited
files by receiving updates about edit actions.

Also, C++ autocompletion is no longer tied to HackStudio itself and
moved to be part of the language server.

4 files changed, 22 insertions, 8 deletions

diff --git a/Libraries/LibGUI/Command.h b/Libraries/LibGUI/Command.h
index 9ff6a0aad9..3b2f081a6a 100644
--- a/Libraries/LibGUI/Command.h
+++ b/Libraries/LibGUI/Command.h
@@ -39,6 +39,9 @@ public:
 
     String action_text() const { return m_action_text; }
 
+    virtual bool is_insert_text() const { return false; }
+    virtual bool is_remove_text() const { return false; }
+
 protected:
     Command() { }
     void set_action_text(const String& text) { m_action_text = text; }
diff --git a/Libraries/LibGUI/TextDocument.cpp b/Libraries/LibGUI/TextDocument.cpp
index 10a5ffe497..35abe1e3ac 100644
--- a/Libraries/LibGUI/TextDocument.cpp
+++ b/Libraries/LibGUI/TextDocument.cpp
@@ -282,6 +282,18 @@ void TextDocument::set_all_cursors(const TextPosition& position)
     }
 }
 
+String TextDocument::text() const
+{
+    StringBuilder builder;
+    for (size_t i = 0; i < line_count(); ++i) {
+        auto& line = this->line(i);
+        builder.append(line.view());
+        if (i != line_count() - 1)
+            builder.append('\n');
+    }
+    return builder.to_string();
+}
+
 String TextDocument::text_in_range(const TextRange& a_range) const
 {
     auto range = a_range.normalized();
diff --git a/Libraries/LibGUI/TextDocument.h b/Libraries/LibGUI/TextDocument.h
index 85fad0e97a..e6ee731ceb 100644
--- a/Libraries/LibGUI/TextDocument.h
+++ b/Libraries/LibGUI/TextDocument.h
@@ -103,6 +103,7 @@ public:
 
     void update_views(Badge<TextDocumentLine>);
 
+    String text() const;
     String text_in_range(const TextRange&) const;
 
     Vector<TextRange> find_all(const StringView& needle) const;
@@ -210,6 +211,9 @@ public:
     InsertTextCommand(TextDocument&, const String&, const TextPosition&);
     virtual void undo() override;
     virtual void redo() override;
+    virtual bool is_insert_text() const override { return true; }
+    const String& text() const { return m_text; }
+    const TextRange& range() const { return m_range; }
 
 private:
     String m_text;
@@ -221,6 +225,8 @@ public:
     RemoveTextCommand(TextDocument&, const String&, const TextRange&);
     virtual void undo() override;
     virtual void redo() override;
+    virtual bool is_remove_text() const override { return true; }
+    const TextRange& range() const { return m_range; }
 
 private:
     String m_text;
diff --git a/Libraries/LibGUI/TextEditor.cpp b/Libraries/LibGUI/TextEditor.cpp
index f67d04cf72..07593715cb 100644
--- a/Libraries/LibGUI/TextEditor.cpp
+++ b/Libraries/LibGUI/TextEditor.cpp
@@ -1254,14 +1254,7 @@ bool TextEditor::write_to_file(const StringView& path)
 
 String TextEditor::text() const
 {
-    StringBuilder builder;
-    for (size_t i = 0; i < line_count(); ++i) {
-        auto& line = this->line(i);
-        builder.append(line.view());
-        if (i != line_count() - 1)
-            builder.append('\n');
-    }
-    return builder.to_string();
+    return document().text();
 }
 
 void TextEditor::clear()