net/instaweb/rewriter/static_asserts_test.cc

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 * 
 *   http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */


// Compile-time only checks of various properties that don't fit anywhere else.
//
// For now this just makes sure that some things are constants so they can be
// used in initializers safely.

#include "pagespeed/kernel/base/basictypes.h"
#include "pagespeed/kernel/base/timer.h"

namespace net_instaweb {
namespace {

// The COMPILE_ASSERTs and enum MustBeConstants are both testing the same thing.
// That Timer::k... are compile-time constants. We include both tests because
// there is enough magic to warrant two different approaches.
COMPILE_ASSERT(Timer::kSecondMs == 1000, seconds_literal);
COMPILE_ASSERT(Timer::kSecondUs == 1000 * 1000, seconds_us_literal);
COMPILE_ASSERT(Timer::kSecondNs == 1000 * 1000 * 1000, seconds_ns_literal);
COMPILE_ASSERT(Timer::kMinuteMs == 60 * 1000, minutes_literal);
COMPILE_ASSERT(Timer::kHourMs   == 60 * 60 * 1000, hours_literal);

// enumerators can only be initialized to compile-time constants, so this
// would not build if any of these weren't compile-time defined.
enum MustBeConstants {
  kSecondMs = Timer::kSecondMs,
  kSecondUs = Timer::kSecondUs,
  kSecondNs = Timer::kSecondNs,
  kMinuteMs = Timer::kMinuteMs,
  kHourMs   = Timer::kHourMs,
  kDayMs    = Timer::kDayMs,
  kWeekMs   = Timer::kWeekMs,
  kMonthMs  = Timer::kMonthMs,
  kYearMs   = Timer::kYearMs
};

}  // namespace
}  // namespace net_instaweb