new loplugin:conststringfield

Look for const string fields which can be static, and
mostly convert them to OUStringLiteral

And add a getLength() method to OUStringLiteral to make
the transition easier.

Remove dead code in XclExpRoot::GenerateDefaultEncryptionData,
default password is never empty.

Change-Id: Iae75514d9dbb87289fd5b016222f640abe755091
Reviewed-on: https://gerrit.libreoffice.org/59204
Tested-by: Jenkins
Reviewed-by: Noel Grandin <noel.grandin@collabora.co.uk>

2 files changed, 100 insertions, 0 deletions

diff --git a/compilerplugins/clang/conststringfield.cxx b/compilerplugins/clang/conststringfield.cxx
new file mode 100644
index 000000000000..23a7db9ebea2
--- /dev/null
+++ b/compilerplugins/clang/conststringfield.cxx
@@ -0,0 +1,57 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/*
+ * This file is part of the LibreOffice project.
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+#include "plugin.hxx"
+#include "check.hxx"
+#include "compat.hxx"
+#include <iostream>
+
+namespace
+{
+class ConstStringField : public loplugin::FilteringPlugin<ConstStringField>
+{
+public:
+    explicit ConstStringField(loplugin::InstantiationData const& data)
+        : loplugin::FilteringPlugin<ConstStringField>(data)
+    {
+    }
+
+    void run() override { TraverseDecl(compiler.getASTContext().getTranslationUnitDecl()); }
+
+    bool TraverseConstructorInitializer(CXXCtorInitializer* init);
+};
+
+bool ConstStringField::TraverseConstructorInitializer(CXXCtorInitializer* init)
+{
+    if (!init->getSourceLocation().isValid() || ignoreLocation(init->getSourceLocation()))
+        return true;
+    if (!init->getMember())
+        return true;
+    auto tc = loplugin::TypeCheck(init->getMember()->getType());
+    if (!tc.Const().Class("OUString").Namespace("rtl").GlobalNamespace()
+        && !tc.Const().Class("OString").Namespace("rtl").GlobalNamespace())
+        return true;
+    if (auto constructExpr = dyn_cast<CXXConstructExpr>(init->getInit()))
+    {
+        if (constructExpr->getNumArgs() >= 1 && isa<clang::StringLiteral>(constructExpr->getArg(0)))
+        {
+            report(DiagnosticsEngine::Warning, "string field can be static const",
+                   init->getSourceLocation())
+                << init->getSourceRange();
+            report(DiagnosticsEngine::Note, "field here", init->getMember()->getLocation())
+                << init->getMember()->getSourceRange();
+        }
+    }
+    return RecursiveASTVisitor::TraverseConstructorInitializer(init);
+}
+
+loplugin::Plugin::Registration<ConstStringField> X("conststringfield", true);
+}
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab: */
diff --git a/compilerplugins/clang/test/conststringfield.cxx b/compilerplugins/clang/test/conststringfield.cxx
new file mode 100644
index 000000000000..fa8785713521
--- /dev/null
+++ b/compilerplugins/clang/test/conststringfield.cxx
@@ -0,0 +1,43 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4; fill-column: 100 -*- */
+/*
+ * This file is part of the LibreOffice project.
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+#include <rtl/ustring.hxx>
+#include <rtl/string.hxx>
+
+class Class1
+{
+    OUString const m_field1; // expected-note {{field here [loplugin:conststringfield]}}
+    Class1()
+        : m_field1("xxxx")
+    // expected-error@-1 {{string field can be static const [loplugin:conststringfield]}}
+    {
+    }
+};
+
+class Class2
+{
+    OString const m_field1; // expected-note {{field here [loplugin:conststringfield]}}
+    Class2()
+        : m_field1("xxxx")
+    // expected-error@-1 {{string field can be static const [loplugin:conststringfield]}}
+    {
+    }
+};
+
+// no warning expected
+class Class4
+{
+    OUString m_field1;
+    Class4()
+        : m_field1("xxxx")
+    {
+    }
+};
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab cinoptions=b1,g0,N-s cinkeys+=0=break: */