CppEditor: Add syntax highlighting for C++ attributes

Fixes: QTCREATORBUG-31241
Change-Id: I7583c3cd08c2ec58ca7702e7758aad6c0e142574
Reviewed-by: David Schulz <david.schulz@qt.io>

share/qtcreator/styles/creator-dark.xml

@@ -29,6 +29,7 @@
   <style name="Function"/>
   <style name="Macro"/>
   <style name="Keyword" foreground="#45c6d6" italic="true"/>
+  <style name="Attribute" foreground="#45c6d6" italic="true"/>
   <style name="PrimitiveType" foreground="#d69aa7"/>
   <style name="Punctuation"/>
   <style name="Operator" foreground="#d6bb9a"/>

share/qtcreator/styles/dark.xml

@@ -19,6 +19,7 @@
   <style name="Macro"/>
   <style name="Global"/>
   <style name="Keyword" foreground="#ffff55"/>
+  <style name="Attribute" foreground="#ffff55"/>
   <style name="PrimitiveType" foreground="#ffff55"/>
   <style name="Label" foreground="#ffff55"/>
   <style name="LineNumber" foreground="#888888" background="#232323"/>

share/qtcreator/styles/default_classic.xml

@@ -25,6 +25,7 @@
   <style name="Function" background="#ffffff"/>
   <style name="Macro" background="#ffffff"/>
   <style name="Keyword" foreground="#808000"/>
+  <style name="Attribute" foreground="#808000"/>
   <style name="PrimitiveType" foreground="#808000"/>
   <style name="Punctuation"/>
   <style name="Operator"/>

share/qtcreator/styles/grayscale.xml

@@ -17,6 +17,7 @@
   <style name="Function"/>
   <style name="Macro"/>
   <style name="Keyword" bold="true"/>
+  <style name="Attribute" bold="true"/>
   <style name="PrimitiveType" bold="true"/>
   <style name="Label"/>
   <style name="LineNumber" foreground="#c7c4c1" background="#efebe7"/>

share/qtcreator/styles/inkpot.xml

@@ -23,6 +23,7 @@
   <style name="Macro"/>
   <style name="Global"/>
   <style name="Keyword" foreground="#808bed"/>
+  <style name="Attribute" foreground="#808bed"/>
   <style name="PrimitiveType" foreground="#808bed"/>
   <style name="Label" foreground="#e76000"/>
   <style name="LineNumber" foreground="#8b8bcd" background="#2e2e2e"/>

share/qtcreator/styles/intellij.xml

@@ -11,6 +11,7 @@
   <style name="Function" foreground="#000000"/>
   <style name="Macro" foreground="#000000"/>
   <style name="Keyword" foreground="#000080" bold="true"/>
+  <style name="Attribute" foreground="#000080" bold="true"/>
   <style name="PrimitiveType" foreground="#000080" bold="true"/>
   <style name="Label" foreground="#800000" bold="true"/>
   <style name="Local" foreground="#000000"/>

share/qtcreator/styles/modnokai_night_shift_v2.xml

@@ -35,6 +35,7 @@
   <style name="Function"/>
   <style name="Macro"/>
   <style name="Keyword" foreground="#78d7ec" italic="true"/>
+  <style name="Attribute" foreground="#78d7ec" italic="true"/>
   <style name="PrimitiveType" foreground="#ff8080"/>
   <style name="Punctuation"/>
   <style name="Operator" foreground="#a6e22e"/>

share/qtcreator/styles/solarized-dark.xml

@@ -35,6 +35,7 @@
   <style name="Function" foreground="#839496"/>
   <style name="Macro" foreground="#839496"/>
   <style name="Keyword" foreground="#709d06"/>
+  <style name="Attribute" foreground="#709d06"/>
   <style name="PrimitiveType" foreground="#808000"/>
   <style name="Punctuation"/>
   <style name="Operator" foreground="#839496"/>

share/qtcreator/styles/solarized-light.xml

@@ -35,6 +35,7 @@
   <style name="Function" foreground="#657b83"/>
   <style name="Macro" foreground="#657b83"/>
   <style name="Keyword" foreground="#709d06"/>
+  <style name="Attribute" foreground="#709d06"/>
   <style name="PrimitiveType" foreground="#808000"/>
   <style name="Punctuation"/>
   <style name="Operator" foreground="#657b83"/>

src/plugins/cppeditor/cpphighlighter.cpp

@@ -33,6 +33,15 @@ using namespace CPlusPlus;
 namespace CppEditor {
 using namespace Internal;
 
+union AttributeState {
+    struct {
+        quint8 lbrackets: 1;
+        quint8 rbrackets: 1;
+        quint8 opened: 6;
+    };
+    quint8 state;
+};
+
 CppHighlighter::CppHighlighter(QTextDocument *document) :
     SyntaxHighlighter(document)
 {
@@ -79,6 +88,8 @@ void CppHighlighter::highlightBlock(const QString &text)
         userData->setFoldingStartIncluded(false);
         userData->setFoldingEndIncluded(false);
     }
+    AttributeState attrState;
+    attrState.state = TextDocumentLayout::attributeState(prevBlock);
 
     if (tokens.isEmpty()) {
         setCurrentBlockState((braceDepth << 8) | lexerState);
@@ -93,6 +104,7 @@ void CppHighlighter::highlightBlock(const QString &text)
         }
         TextDocumentLayout::setFoldingIndent(currentBlock(), foldingIndent);
         TextDocumentLayout::setExpectedRawStringSuffix(currentBlock(), inheritedRawStringSuffix);
+        TextDocumentLayout::setAttributeState(currentBlock(), attrState.state);
         qCDebug(highlighterLog) << "no tokens, storing brace depth" << braceDepth << "and foldingIndent"
                      << foldingIndent;
         return;
@@ -185,6 +197,25 @@ void CppHighlighter::highlightBlock(const QString &text)
         if (onlyHighlightComments && !tk.isComment())
             continue;
 
+        // Handle attributes, i.e. identifiers in pairs of "[[" and "]]".
+        if (tk.is(T_LBRACKET) && !tk.isOperator()) {
+            attrState.lbrackets = !attrState.lbrackets;
+            if (attrState.lbrackets == 0)
+                ++attrState.opened;
+            continue;
+        }
+        if (tk.is(T_RBRACKET) && !tk.isOperator()) {
+            attrState.rbrackets = !attrState.rbrackets;
+            if (attrState.rbrackets == 0 && attrState.opened > 0)
+                --attrState.opened;
+            continue;
+        }
+        attrState.lbrackets = attrState.rbrackets = 0;
+        if (attrState.opened && (tk.is(T_IDENTIFIER) || (tk.isKeyword() && !tk.is(T_USING)))) {
+            setFormat(tk.utf16charsBegin(), tk.utf16chars(), formatForCategory(C_ATTRIBUTE));
+            continue;
+        }
+
         if (i == 0 && tk.is(T_POUND)) {
             setFormatWithSpaces(text, tk.utf16charsBegin(), tk.utf16chars(),
                           formatForCategory(C_PREPROCESSOR));
@@ -297,6 +328,7 @@ void CppHighlighter::highlightBlock(const QString &text)
     }
 
     TextDocumentLayout::setParentheses(currentBlock(), parentheses);
+    TextDocumentLayout::setAttributeState(currentBlock(), attrState.state);
 
     TextDocumentLayout::setFoldingIndent(currentBlock(), foldingIndent);
     setCurrentBlockState(rehighlightNextBlock | (braceDepth << 8) | tokenize.state());
@@ -655,6 +687,46 @@ private slots:
             << 73 << 17 << 73 << 18 << C_STRING;
         QTest::newRow("wide char literal with user-defined suffix (suffix)")
             << 73 << 20 << 73 << 22 << C_OVERLOADED_OPERATOR;
+        QTest::newRow("separate attributes specs, 1/4, namespace")
+            << 75 << 3 << 72 << 5 << C_ATTRIBUTE;
+        QTest::newRow("separate attributes specs, 1/4, attr")
+            << 75 << 8 << 72 << 20 << C_ATTRIBUTE;
+        QTest::newRow("separate attributes specs, 2/4, namespace")
+            << 75 << 26 << 72 << 28 << C_ATTRIBUTE;
+        QTest::newRow("separate attributes specs, 2/4, attr")
+            << 75 << 31 << 72 << 33 << C_ATTRIBUTE;
+        QTest::newRow("separate attributes specs, 3/4, namespace")
+            << 75 << 39 << 72 << 41 << C_ATTRIBUTE;
+        QTest::newRow("separate attributes specs, 3/4, attr")
+            << 75 << 44 << 72 << 48 << C_ATTRIBUTE;
+        QTest::newRow("separate attributes specs, 4/4, attr")
+            << 75 << 54 << 72 << 62 << C_ATTRIBUTE;
+        QTest::newRow("single attributes spec, 1/4, namespace")
+            << 76 << 3 << 73 << 5 << C_ATTRIBUTE;
+        QTest::newRow("single attributes spec, 1/4, attr")
+            << 76 << 8 << 73 << 20 << C_ATTRIBUTE;
+        QTest::newRow("single attributes spec, 2/4, namespace")
+            << 76 << 23 << 73 << 25 << C_ATTRIBUTE;
+        QTest::newRow("single attributes spec, 2/4, attr")
+            << 76 << 28 << 73 << 32 << C_ATTRIBUTE;
+        QTest::newRow("single attributes spec, 3/4, namespace")
+            << 76 << 35 << 73 << 37 << C_ATTRIBUTE;
+        QTest::newRow("single attributes spec, 3/4, attr")
+            << 76 << 40 << 73 << 42 << C_ATTRIBUTE;
+        QTest::newRow("single attributes spec, 4/4, attr")
+            << 76 << 45 << 73 << 53 << C_ATTRIBUTE;
+        QTest::newRow("attributes with using, namespace")
+            << 77 << 9 << 74 << 11 << C_ATTRIBUTE;
+        QTest::newRow("attributes with using, attr 1/3")
+            << 77 << 15 << 74 << 19 << C_ATTRIBUTE;
+        QTest::newRow("attributes with using, attr 2/3")
+            << 77 << 22 << 74 << 34 << C_ATTRIBUTE;
+        QTest::newRow("attributes with using, attr 3/3")
+            << 77 << 37 << 74 << 39 << C_ATTRIBUTE;
+        QTest::newRow("attribute with line split, namespace")
+            << 79 << 9 << 76 << 11 << C_ATTRIBUTE;
+        QTest::newRow("attribute with line split, attr")
+            << 79 << 14 << 76 << 26 << C_ATTRIBUTE;
     }
 
     void test()

src/plugins/cppeditor/testcases/highlightingtestcase.cpp

@@ -71,3 +71,10 @@ static void parenTest2()
 
 wchar_t operator ""_wc(const wchar_t c) { return c; }
 const auto c = L'c'_wc;
+
+[[gnu::always_inline]] [[gnu::hot]] [[gnu::const]] [[nodiscard]] int attr1();
+[[gnu::always_inline, gnu::const, gnu::hot, nodiscard]] int attr2();
+[[using gnu : const, always_inline, hot]] int attr3[
+    [
+        gnu::always_inline]
+]();

src/plugins/texteditor/textdocumentlayout.cpp

@@ -543,6 +543,21 @@ TextSuggestion *TextDocumentLayout::suggestion(const QTextBlock &block)
     return nullptr;
 }
 
+void TextDocumentLayout::setAttributeState(const QTextBlock &block, quint8 attrState)
+{
+    if (TextBlockUserData * const data = textUserData(block))
+        data->setAttrState(attrState);
+    else if (attrState)
+        userData(block)->setAttrState(attrState);
+}
+
+quint8 TextDocumentLayout::attributeState(const QTextBlock &block)
+{
+    if (TextBlockUserData *userData = textUserData(block))
+        return userData->attrState();
+    return 0;
+}
+
 void TextDocumentLayout::updateSuggestionFormats(const QTextBlock &block,
                                                  const FontSettings &fontSettings)
 {

src/plugins/texteditor/textdocumentlayout.h

@@ -153,6 +153,9 @@ public:
     TextSuggestion *suggestion() const;
     void clearSuggestion();
 
+    void setAttrState(quint8 state) { m_attrState = state; }
+    quint8 attrState() const { return m_attrState; }
+
 private:
     TextMarks m_marks;
     int m_foldingIndent : 16;
@@ -168,6 +171,7 @@ private:
     QByteArray m_expectedRawStringSuffix; // A bit C++-specific, but let's be pragmatic.
     std::unique_ptr<QTextDocument> m_replacement;
     std::unique_ptr<TextSuggestion> m_suggestion;
+    quint8 m_attrState = 0;
 };
 
 class TEXTEDITOR_EXPORT TextDocumentLayout : public QPlainTextDocumentLayout
@@ -201,6 +205,8 @@ public:
     static void setExpectedRawStringSuffix(const QTextBlock &block, const QByteArray &suffix);
     static QByteArray expectedRawStringSuffix(const QTextBlock &block);
     static TextSuggestion *suggestion(const QTextBlock &block);
+    static void setAttributeState(const QTextBlock &block, quint8 attrState);
+    static quint8 attributeState(const QTextBlock &block);
     static void updateSuggestionFormats(const QTextBlock &block,
                                         const FontSettings &fontSettings);
     static bool updateSuggestion(const QTextBlock &block,

src/plugins/texteditor/texteditorconstants.cpp

@@ -52,6 +52,7 @@ const char *nameForStyle(TextStyle style)
     case C_PREPROCESSOR:        return "Preprocessor";
     case C_MACRO:               return "Macro";
     case C_LABEL:               return "Label";
+    case C_ATTRIBUTE:           return "Attribute";
     case C_COMMENT:             return "Comment";
     case C_DOXYGEN_COMMENT:     return "Doxygen.Comment";
     case C_DOXYGEN_TAG:         return "Doxygen.Tag";

src/plugins/texteditor/texteditorconstants.h

@@ -50,6 +50,7 @@ enum TextStyle : quint8 {
     C_PREPROCESSOR,
     C_MACRO,
     C_LABEL,
+    C_ATTRIBUTE,
     C_COMMENT,
     C_DOXYGEN_COMMENT,
     C_DOXYGEN_TAG,

src/plugins/texteditor/texteditorsettings.cpp

@@ -251,6 +251,8 @@ FormatDescriptions TextEditorSettingsPrivate::initialFormats()
                              Tr::tr("Macros."), functionFormat);
     formatDescr.emplace_back(C_LABEL, Tr::tr("Label"), Tr::tr("Labels for goto statements."),
                              Qt::darkRed);
+    formatDescr.emplace_back(C_ATTRIBUTE, Tr::tr("Attribute"), Tr::tr("Attributes."),
+                             Qt::darkYellow);
     formatDescr.emplace_back(C_COMMENT, Tr::tr("Comment"),
                              Tr::tr("All style of comments except Doxygen comments."),
                              Qt::darkGreen);