/* 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 "EmptyBasesChecker.h"
#include "CustomMatchers.h"

namespace clang {
namespace ast_matchers {

AST_MATCHER_P(CXXRecordDecl, emptyBaseCountAtLeast, unsigned, N) {
  unsigned NumEmptyBases = 0;
  for (const auto &Base : Node.bases()) {
    if (const Type *BaseType = Base.getType().getTypePtrOrNull()) {
      if (const CXXRecordDecl *CRD = BaseType->getAsCXXRecordDecl();
          CRD && CRD->isEmpty())
        NumEmptyBases += 1;
    }
  }
  return NumEmptyBases >= N;
}

AST_MATCHER(CXXRecordDecl, hasMozEmptyBasesAttr) {
  return Node.hasAttr<EmptyBasesAttr>();
}

} // namespace ast_matchers

} // namespace clang

void EmptyBasesChecker::registerMatchers(MatchFinder *AstMatcher) {
  AstMatcher->addMatcher(cxxRecordDecl(isDefinition(), isFirstParty(),
                                       emptyBaseCountAtLeast(2),
                                       unless(hasMozEmptyBasesAttr()))
                             .bind("class"),
                         this);
}

void EmptyBasesChecker::check(const MatchFinder::MatchResult &Result) {
  const CXXRecordDecl *Cls = Result.Nodes.getNodeAs<CXXRecordDecl>("class");
  diag(Cls->getBeginLoc(), "Missing MOZ_EMPTY_BASES", DiagnosticIDs::Error);
}