[ClangFormat] Add test checkking indentation after Q_OBJECT

Added test checking behavior when after Q_OBJECT all class structure
have correct indenting and redundent tabs doesn't appear before key words
such as  public:, private: , etc.
Made automatic addition Qt defines to StatementMacro to .clang-format files.

Fixes: QTCREATORBUG-26776
Change-Id: I3490421a9caf2831b593939597940358f7ce8f01
Reviewed-by: Christian Kandeler <christian.kandeler@qt.io>

src/plugins/clangformat/clangformatbaseindenter.cpp

@@ -24,6 +24,7 @@
 ****************************************************************************/
 
 #include "clangformatbaseindenter.h"
+#include "clangformatutils.h"
 
 #include <clang/Tooling/Core/Replacement.h>
 
@@ -728,14 +729,16 @@ clang::format::FormatStyle ClangFormatBaseIndenter::styleForFile() const
 {
     llvm::Expected<clang::format::FormatStyle> style
         = clang::format::getStyle("file", m_fileName.toString().toStdString(), "none");
-    if (style)
+    if (style) {
+        addQtcStatementMacros(*style);
         return *style;
+    }
 
     handleAllErrors(style.takeError(), [](const llvm::ErrorInfoBase &) {
         // do nothing
     });
 
-    return clang::format::getLLVMStyle();
+    return qtcStyle();
 }
 
 } // namespace ClangFormat

src/plugins/clangformat/clangformatutils.cpp

@@ -33,6 +33,7 @@
 #include <texteditor/tabsettings.h>
 #include <projectexplorer/project.h>
 #include <projectexplorer/session.h>
+#include <utils/qtcassert.h>
 
 #include <QCryptographicHash>
 
@@ -46,7 +47,7 @@ using namespace Utils;
 
 namespace ClangFormat {
 
-static clang::format::FormatStyle qtcStyle()
+clang::format::FormatStyle qtcStyle()
 {
     clang::format::FormatStyle style = getLLVMStyle();
     style.Language = FormatStyle::LK_Cpp;
@@ -355,18 +356,38 @@ clang::format::FormatStyle styleForFile(Utils::FilePath fileName)
     return styleForFile(fileName, true);
 }
 
+void addQtcStatementMacros(clang::format::FormatStyle &style)
+{
+    static const std::vector<std::string> macros = {"Q_OBJECT",
+                                                    "QT_BEGIN_NAMESPACE",
+                                                    "QT_END_NAMESPACE"};
+    for (const std::string &macro : macros) {
+        if (std::find(style.StatementMacros.begin(), style.StatementMacros.end(), macro)
+            == style.StatementMacros.end())
+            style.StatementMacros.emplace_back(macro);
+    }
+}
+
 static std::string readFile(const QString &path)
 {
+    const std::string defaultStyle = clang::format::configurationAsText(qtcStyle());
+
     QFile file(path);
-    if (!file.open(QFile::ReadOnly)) {
-        clang::format::FormatStyle defaultStyle = qtcStyle();
-        return clang::format::configurationAsText(defaultStyle);
-    }
+    if (!file.open(QFile::ReadOnly))
+        return defaultStyle;
 
     const QByteArray content = file.readAll();
     file.close();
 
-    return content.toStdString();
+    clang::format::FormatStyle style;
+    style.Language = clang::format::FormatStyle::LK_Cpp;
+    const std::error_code error = clang::format::parseConfiguration(content.toStdString(), &style);
+
+    QTC_ASSERT(error.value() == static_cast<int>(ParseError::Success), return defaultStyle);
+
+    addQtcStatementMacros(style);
+
+    return clang::format::configurationAsText(style);
 }
 
 std::string currentProjectConfigText()

src/plugins/clangformat/clangformatutils.h

@@ -51,4 +51,6 @@ clang::format::FormatStyle currentGlobalStyle();
 QString configForFile(Utils::FilePath fileName);
 clang::format::FormatStyle styleForFile(Utils::FilePath fileName);
 
+void addQtcStatementMacros(clang::format::FormatStyle &style);
+clang::format::FormatStyle qtcStyle();
 }

src/plugins/clangformat/tests/clangformat-test.cpp

@@ -646,4 +646,12 @@ void ClangFormatTest::testCommentBlock()
                     "****************************************************************************/"}));
 }
 
+void ClangFormatTest::testClassIndentStructure()
+{
+    insertLines({"class test {", "    Q_OBJECT", "    public:", "};"});
+    m_indenter->indent(*m_cursor, QChar::Null, TextEditor::TabSettings());
+    QCOMPARE(documentLines(),
+             (std::vector<QString>{"class test {", "    Q_OBJECT", "public:", "};"}));
+}
+
 } // namespace ClangFormat::Internal

src/plugins/clangformat/tests/clangformat-test.h

@@ -109,6 +109,7 @@ private slots:
     void testSortIncludes();
     void testChainedMemberFunctionCalls();
     void testCommentBlock();
+    void testClassIndentStructure();
 
 private:
     void insertLines(const std::vector<QString> &lines);