// Copyright 2021 The Abseil Authors // // Licensed 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 // // https://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. #ifndef ABSL_STRINGS_INTERNAL_CORDZ_UPDATE_SCOPE_H_ #define ABSL_STRINGS_INTERNAL_CORDZ_UPDATE_SCOPE_H_ #include "absl/base/config.h" #include "absl/base/optimization.h" #include "absl/base/thread_annotations.h" #include "absl/strings/internal/cord_internal.h" #include "absl/strings/internal/cordz_info.h" #include "absl/strings/internal/cordz_update_tracker.h" namespace absl { ABSL_NAMESPACE_BEGIN namespace cord_internal { // CordzUpdateScope scopes an update to the provided CordzInfo. // The class invokes `info->Lock(method)` and `info->Unlock()` to guard // cordrep updates. This class does nothing if `info` is null. // See also the 'Lock`, `Unlock` and `SetCordRep` methods in `CordzInfo`. class ABSL_SCOPED_LOCKABLE CordzUpdateScope { public: CordzUpdateScope(CordzInfo* info, CordzUpdateTracker::MethodIdentifier method) ABSL_EXCLUSIVE_LOCK_FUNCTION(info) : info_(info) { if (ABSL_PREDICT_FALSE(info_)) { info->Lock(method); } } // CordzUpdateScope can not be copied or assigned to. CordzUpdateScope(CordzUpdateScope&& rhs) = delete; CordzUpdateScope(const CordzUpdateScope&) = delete; CordzUpdateScope& operator=(CordzUpdateScope&& rhs) = delete; CordzUpdateScope& operator=(const CordzUpdateScope&) = delete; ~CordzUpdateScope() ABSL_UNLOCK_FUNCTION() { if (ABSL_PREDICT_FALSE(info_)) { info_->Unlock(); } } void SetCordRep(CordRep* rep) const { if (ABSL_PREDICT_FALSE(info_)) { info_->SetCordRep(rep); } } CordzInfo* info() const { return info_; } private: CordzInfo* info_; }; } // namespace cord_internal ABSL_NAMESPACE_END } // namespace absl #endif // ABSL_STRINGS_INTERNAL_CORDZ_UPDATE_SCOPE_H_