Store compilerplugin warning about classes derived from a specific class.

Useful in case someone wants to find all classes deriving from "foo" and "bar".

Change-Id: I7b12882881712d37976eb8c96fad6e9c9ac01370

compilerplugins/clang/store/derivedclass.cxx

+/* -*- 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"
+
+namespace {
+
+class DerivedClass:
+    public RecursiveASTVisitor<DerivedClass>,
+    public loplugin::Plugin
+{
+public:
+    explicit DerivedClass(InstantiationData const & data):
+        Plugin(data) {}
+
+    virtual void run() override
+    { TraverseDecl(compiler.getASTContext().getTranslationUnitDecl()); }
+
+    bool VisitCXXRecordDecl(CXXRecordDecl const * decl);
+};
+
+bool BaseCheck(const CXXRecordDecl *BaseDefinition, void *BaseClassName) {
+    // print warning about deriving from this classes
+    // the name has to contain namespace, e.g. foo::bar::ClassName
+    const char *BaseClasses[] = {
+        "Dialog",
+        "ProgressBar",
+        "SfxToolBoxControl",
+        "StatusBar",
+        0,
+    };
+    for (int i = 0; BaseClasses[i]; i++)
+        if (BaseDefinition->getQualifiedNameAsString().compare(BaseClasses[i]) == 0) {
+            *(const char **)BaseClassName = BaseClasses[i];
+            return false;
+        }
+    return true;
+}
+
+bool DerivedClass::VisitCXXRecordDecl(CXXRecordDecl const * decl) {
+    const char *BaseClassName = 0;
+    // checking for decl->hasDefinition() avoids crash in decl->forallBases
+    if (decl->hasDefinition() &&
+            // not sure what hasAnyDependentBases() does,
+            // but it avoids classes we don't want, e.g. WeakAggComponentImplHelper1
+            !decl->hasAnyDependentBases() &&
+            !decl->forallBases(BaseCheck, &BaseClassName)) {
+        string warning_msg("class %0 derives from ");
+        // no idea how BaseClassName can be 0 sometimes..
+        if (BaseClassName)
+            warning_msg += BaseClassName;
+        report(
+            DiagnosticsEngine::Warning,
+            warning_msg,
+            decl->getLocStart())
+        << decl->getQualifiedNameAsString() << decl->getSourceRange();
+    }
+    return true;
+}
+
+loplugin::Plugin::Registration<DerivedClass> X("derivedclass");
+
+}
+
+/* vim:set shiftwidth=4 softtabstop=4 tabstop=4 expandtab: */