ceph/src/zstd/contrib/pzstd/ErrorHolder.h

   1 /**
   2  * Copyright (c) 2016-present, Facebook, Inc.
   3  * All rights reserved.
   4  *
   5  * This source code is licensed under the BSD-style license found in the
   6  * LICENSE file in the root directory of this source tree. An additional grant
   7  * of patent rights can be found in the PATENTS file in the same directory.
   8  */
   9 #pragma once
  10
  11 #include <atomic>
  12 #include <cassert>
  13 #include <stdexcept>
  14 #include <string>
  15
  16 namespace pzstd {
  17
  18 // Coordinates graceful shutdown of the pzstd pipeline
  19 class ErrorHolder {
  20   std::atomic<bool> error_;
  21   std::string message_;
  22
  23  public:
  24   ErrorHolder() : error_(false) {}
  25
  26   bool hasError() noexcept {
  27     return error_.load();
  28   }
  29
  30   void setError(std::string message) noexcept {
  31     // Given multiple possibly concurrent calls, exactly one will ever succeed.
  32     bool expected = false;
  33     if (error_.compare_exchange_strong(expected, true)) {
  34       message_ = std::move(message);
  35     }
  36   }
  37
  38   bool check(bool predicate, std::string message) noexcept {
  39     if (!predicate) {
  40       setError(std::move(message));
  41     }
  42     return !hasError();
  43   }
  44
  45   std::string getError() noexcept {
  46     error_.store(false);
  47     return std::move(message_);
  48   }
  49
  50   ~ErrorHolder() {
  51     assert(!hasError());
  52   }
  53 };
  54 }