move isDerivedFrom() from a clang plugin to shared code, for reuse

Change-Id: I7b9b41a7081281214a387cdf02080866e9b9dfe7
Reviewed-on: https://gerrit.libreoffice.org/68873
Tested-by: Jenkins
Reviewed-by: Noel Grandin <noel.grandin@collabora.co.uk>

compilerplugins/clang/check.cxx

@@ -280,6 +280,35 @@ bool isOkToRemoveArithmeticCast(
     return true;
 }
 
+
+static bool BaseCheckNotSubclass(const clang::CXXRecordDecl *BaseDefinition, void *p) {
+    if (!BaseDefinition)
+        return true;
+    auto const & base = *static_cast<const DeclChecker *>(p);
+    if (base(BaseDefinition)) {
+        return false;
+    }
+    return true;
+}
+
+bool isDerivedFrom(const clang::CXXRecordDecl *decl, DeclChecker base) {
+    if (!decl)
+        return false;
+    if (base(decl))
+        return true;
+    if (!decl->hasDefinition()) {
+        return false;
+    }
+    if (!decl->forallBases(
+            [&base](const clang::CXXRecordDecl *BaseDefinition) -> bool
+                { return BaseCheckNotSubclass(BaseDefinition, &base); },
+            true))
+    {
+        return true;
+    }
+    return false;
+}
+
 }
 
 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */

compilerplugins/clang/check.hxx

@@ -140,6 +140,12 @@ private:
     bool const satisfied_;
 };
 
+
+typedef std::function<bool(clang::Decl const *)> DeclChecker;
+// Returns true if the class has a base matching the checker, or if the class itself matches.
+bool isDerivedFrom(const clang::CXXRecordDecl *decl, DeclChecker base);
+
+
 namespace detail {
 
 ContextCheck checkRecordDecl(

compilerplugins/clang/refcounting.cxx

@@ -35,7 +35,7 @@ not delete on last 'release'.
 
 */
 
-namespace {
+namespace loplugin {
 
 class RefCounting:
     public loplugin::FilteringPlugin<RefCounting>
@@ -72,37 +72,6 @@ private:
     bool visitTemporaryObjectExpr(Expr const * expr);
 };
 
-typedef std::function<bool(Decl const *)> DeclChecker;
-
-bool BaseCheckNotSubclass(const CXXRecordDecl *BaseDefinition, void *p) {
-    if (!BaseDefinition)
-        return true;
-    auto const & base = *static_cast<const DeclChecker *>(p);
-    if (base(BaseDefinition)) {
-        return false;
-    }
-    return true;
-}
-
-bool isDerivedFrom(const CXXRecordDecl *decl, DeclChecker base) {
-    if (!decl)
-        return false;
-    if (base(decl))
-        return true;
-    if (!decl->hasDefinition()) {
-        return false;
-    }
-    if (!decl->forallBases(
-            [&base](const CXXRecordDecl *BaseDefinition) -> bool
-                { return BaseCheckNotSubclass(BaseDefinition, &base); },
-            true))
-    {
-        return true;
-    }
-    return false;
-}
-
-
 bool containsXInterfaceSubclass(const clang::Type* pType0);
 
 bool containsXInterfaceSubclass(const QualType& qType) {