blob: bf06003fdfbe0c316fa52699b46a54b8c6774446 [file] [log] [blame]
// Copyright 2019 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "chrome/browser/unexpire_flags.h"
#include "base/no_destructor.h"
#include "chrome/browser/expired_flags_list.h"
namespace flags {
namespace {
class FlagPredicateSingleton {
public:
FlagPredicateSingleton() = default;
~FlagPredicateSingleton() = default;
static const testing::FlagPredicate& GetPredicate() {
return GetInstance()->predicate_;
}
static void SetPredicate(testing::FlagPredicate predicate) {
GetInstance()->predicate_ = predicate;
}
private:
static FlagPredicateSingleton* GetInstance() {
static base::NoDestructor<FlagPredicateSingleton> instance;
return instance.get();
}
testing::FlagPredicate predicate_;
};
} // namespace
const base::Feature kUnexpireFlagsM76{"TemporaryUnexpireFlagsM76",
base::FEATURE_DISABLED_BY_DEFAULT};
const base::Feature kUnexpireFlagsM78{"TemporaryUnexpireFlagsM78",
base::FEATURE_DISABLED_BY_DEFAULT};
bool ExpiryEnabledForMstone(int mstone) {
// generate_expired_list.py will never emit flags with expiry milestone -1, to
// keep binary size down. However, if a bug *did* cause that to happen, and
// this function did not handle that case, disaster could ensue: all the -1
// flags that are supposed to never expire would in fact expire instantly,
// since -1 < x for any valid mstone x.
// As such, there's an extra error-check here: never allow flags with mstone
// -1 to expire.
DCHECK(mstone != -1);
if (mstone == -1)
return false;
// In M78 this expired flags with their expirations set to M76 or earlier.
// In M79 this expires flags with their expirations set to M78 or earlier.
// In M80 and later, this will expire any flags whose expiration is <= the
// current mstone, and this block comment will go away along with these
// special cases.
if (mstone < 76)
return true;
if (mstone == 76)
return !base::FeatureList::IsEnabled(kUnexpireFlagsM76);
if (mstone == 77 || mstone == 78)
return !base::FeatureList::IsEnabled(kUnexpireFlagsM78);
return false;
}
bool IsFlagExpired(const char* internal_name) {
if (FlagPredicateSingleton::GetPredicate())
return FlagPredicateSingleton::GetPredicate().Run(internal_name);
for (int i = 0; kExpiredFlags[i].name; ++i) {
const ExpiredFlag* f = &kExpiredFlags[i];
if (!strcmp(f->name, internal_name) && ExpiryEnabledForMstone(f->mstone))
return true;
}
return false;
}
namespace testing {
void SetFlagExpiredPredicate(FlagPredicate predicate) {
FlagPredicateSingleton::SetPredicate(predicate);
}
} // namespace testing
} // namespace flags