1 files changed, 71 insertions, 0 deletions
diff --git a/third_party/abseil-cpp/absl/strings/internal/cordz_update_scope.h b/third_party/abseil-cpp/absl/strings/internal/cordz_update_scope.h
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+++ b/third_party/abseil-cpp/absl/strings/internal/cordz_update_scope.h
@@ -0,0 +1,71 @@
+// 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_