LibGUI: Add Javascript syntax highlighter

Author: https://github.com/oriko1010
Commit: https://github.com/SerenityOS/serenity/commit/196352ef671
Pull-request: https://github.com/SerenityOS/serenity/pull/1435

Libraries/LibGUI/JSSyntaxHighlighter.cpp

@@ -0,0 +1,157 @@
+#include <LibGUI/JSSyntaxHighlighter.h>
+#include <LibGUI/TextEditor.h>
+#include <LibGfx/Font.h>
+#include <LibJS/Lexer.h>
+#include <LibJS/Token.h>
+
+namespace GUI {
+
+static TextStyle style_for_token_type(JS::TokenType type)
+{
+    switch (type) {
+    case JS::TokenType::BoolLiteral:
+    case JS::TokenType::NullLiteral:
+        return { Color::Black, &Gfx::Font::default_bold_fixed_width_font() };
+    case JS::TokenType::Catch:
+    case JS::TokenType::Class:
+    case JS::TokenType::Const:
+    case JS::TokenType::Delete:
+    case JS::TokenType::Do:
+    case JS::TokenType::Else:
+    case JS::TokenType::Finally:
+    case JS::TokenType::For:
+    case JS::TokenType::Function:
+    case JS::TokenType::If:
+    case JS::TokenType::Interface:
+    case JS::TokenType::Let:
+    case JS::TokenType::New:
+    case JS::TokenType::QuestionMark:
+    case JS::TokenType::Return:
+    case JS::TokenType::Try:
+    case JS::TokenType::Var:
+    case JS::TokenType::While:
+        return { Color::Black, &Gfx::Font::default_bold_fixed_width_font() };
+    case JS::TokenType::Identifier:
+        return { Color::from_rgb(0x092e64) };
+    case JS::TokenType::NumericLiteral:
+    case JS::TokenType::StringLiteral:
+    case JS::TokenType::RegexLiteral:
+        return { Color::from_rgb(0x800000) };
+    case JS::TokenType::Invalid:
+    case JS::TokenType::Eof:
+        return { Color::from_rgb(0x008000) };
+    default:
+        return { Color::Black };
+    }
+}
+
+bool JSSyntaxHighlighter::is_identifier(void* token) const
+{
+    auto js_token = static_cast<JS::TokenType>(reinterpret_cast<size_t>(token));
+    return js_token == JS::TokenType::Identifier;
+}
+
+bool JSSyntaxHighlighter::is_navigatable(void* token) const
+{
+    (void)token;
+    return false;
+}
+
+void JSSyntaxHighlighter::rehighlight()
+{
+    ASSERT(m_editor);
+    auto text = m_editor->text();
+
+    JS::Lexer lexer(text);
+
+    Vector<GUI::TextDocumentSpan> spans;
+    GUI::TextPosition position { 0, 0 };
+    GUI::TextPosition start { 0, 0 };
+
+    auto advance_position = [&](char ch) {
+        if (ch == '\n') {
+            position.set_line(position.line() + 1);
+            position.set_column(0);
+        } else
+            position.set_column(position.column() + 1);
+    };
+
+    bool was_eof = false;
+    for (auto token = lexer.next(); !was_eof; token = lexer.next()) {
+        start = position;
+        if (!token.trivia().is_empty()) {
+            for (auto ch : token.trivia())
+                advance_position(ch);
+
+            GUI::TextDocumentSpan span;
+
+            span.range.set_start(start);
+            if (position.column() > 0)
+                span.range.set_end({ position.line(), position.column() - 1 });
+            else
+                span.range.set_end({ position.line() - 1, 0 });
+            auto style = style_for_token_type(JS::TokenType::Invalid);
+            span.color = style.color;
+            span.font = style.font;
+            span.is_skippable = true;
+            spans.append(span);
+#ifdef DEBUG_SYNTAX_HIGHLIGHTING
+            dbg() << token.name() << " \"" << token.trivia() << "\" (trivia) @ " << span.range.start().line() << ":" << span.range.start().column() << " - " << span.range.end().line() << ":" << span.range.end().column();
+#endif
+        }
+
+        start = position;
+        if (!token.value().is_empty()) {
+            for (auto ch : token.value())
+                advance_position(ch);
+
+            GUI::TextDocumentSpan span;
+            span.range.set_start(start);
+            if (position.column() > 0)
+                span.range.set_end({ position.line(), position.column() - 1 });
+            else
+                span.range.set_end({ position.line() - 1, 0 });
+            auto style = style_for_token_type(token.type());
+            span.color = style.color;
+            span.font = style.font;
+            span.is_skippable = false;
+            span.data = reinterpret_cast<void*>(token.type());
+            spans.append(span);
+#ifdef DEBUG_SYNTAX_HIGHLIGHTING
+            dbg() << token.name() << " @ \"" << token.value() << "\" " << span.range.start().line() << ":" << span.range.start().column() << " - " << span.range.end().line() << ":" << span.range.end().column();
+#endif
+        }
+
+        if (token.type() == JS::TokenType::Eof)
+            was_eof = true;
+    }
+
+    m_editor->document().set_spans(spans);
+
+    m_has_brace_buddies = false;
+    highlight_matching_token_pair();
+
+    m_editor->update();
+}
+
+Vector<SyntaxHighlighter::MatchingTokenPair> JSSyntaxHighlighter::matching_token_pairs() const
+{
+    static Vector<SyntaxHighlighter::MatchingTokenPair> pairs;
+    if (pairs.is_empty()) {
+        pairs.append({ reinterpret_cast<void*>(JS::TokenType::CurlyOpen), reinterpret_cast<void*>(JS::TokenType::CurlyClose) });
+        pairs.append({ reinterpret_cast<void*>(JS::TokenType::ParenOpen), reinterpret_cast<void*>(JS::TokenType::ParenClose) });
+        pairs.append({ reinterpret_cast<void*>(JS::TokenType::BracketOpen), reinterpret_cast<void*>(JS::TokenType::BracketClose) });
+    }
+    return pairs;
+}
+
+bool JSSyntaxHighlighter::token_types_equal(void* token1, void* token2) const
+{
+    return static_cast<JS::TokenType>(reinterpret_cast<size_t>(token1)) == static_cast<JS::TokenType>(reinterpret_cast<size_t>(token2));
+}
+
+JSSyntaxHighlighter::~JSSyntaxHighlighter()
+{
+}
+
+}

Libraries/LibGUI/JSSyntaxHighlighter.h

@@ -0,0 +1,23 @@
+#pragma once
+
+#include <LibGUI/SyntaxHighlighter.h>
+
+namespace GUI {
+
+class JSSyntaxHighlighter final : public SyntaxHighlighter {
+public:
+    JSSyntaxHighlighter() {}
+    virtual ~JSSyntaxHighlighter() override;
+
+    virtual bool is_identifier(void*) const override;
+    virtual bool is_navigatable(void*) const override;
+
+    virtual SyntaxLanguage language() const override { return SyntaxLanguage::Javascript; }
+    virtual void rehighlight() override;
+
+protected:
+    virtual Vector<MatchingTokenPair> matching_token_pairs() const override;
+    virtual bool token_types_equal(void*, void*) const override;
+};
+
+}

Libraries/LibGUI/Makefile

@@ -29,6 +29,7 @@ OBJS = \
     InputBox.o \
     ItemView.o \
     JsonArrayModel.o \
+    JSSyntaxHighlighter.o \
     Label.o \
     Layout.o \
     LazyWidget.o \