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       1                 :             : // Copyright (c) 2024-present The Bitcoin Core developers
       2                 :             : // Distributed under the MIT software license, see the accompanying
       3                 :             : // file COPYING or http://www.opensource.org/licenses/mit-license.php.
       4                 :             : 
       5                 :             : #ifndef BITCOIN_NODE_TIMEOFFSETS_H
       6                 :             : #define BITCOIN_NODE_TIMEOFFSETS_H
       7                 :             : 
       8                 :             : #include <sync.h>
       9                 :             : 
      10                 :             : #include <chrono>
      11                 :             : #include <cstddef>
      12                 :             : #include <deque>
      13                 :             : 
      14                 :             : namespace node {
      15                 :             : class Warnings;
      16                 :             : } // namespace node
      17                 :             : 
      18                 :           5 : class TimeOffsets
      19                 :             : {
      20                 :             : public:
      21                 :         176 :     TimeOffsets(node::Warnings& warnings) : m_warnings{warnings} {}
      22                 :             : 
      23                 :             : private:
      24                 :             :     //! Maximum number of timeoffsets stored.
      25                 :             :     static constexpr size_t MAX_SIZE{50};
      26                 :             :     //! Minimum difference between system and network time for a warning to be raised.
      27                 :             :     static constexpr std::chrono::minutes WARN_THRESHOLD{10};
      28                 :             : 
      29                 :             :     mutable Mutex m_mutex;
      30                 :             :     /** The observed time differences between our local clock and those of our outbound peers. A
      31                 :             :      * positive offset means our peer's clock is ahead of our local clock. */
      32                 :             :     std::deque<std::chrono::seconds> m_offsets GUARDED_BY(m_mutex){};
      33                 :             : 
      34                 :             :     node::Warnings& m_warnings;
      35                 :             : 
      36                 :             : public:
      37                 :             :     /** Add a new time offset sample. */
      38                 :             :     void Add(std::chrono::seconds offset) EXCLUSIVE_LOCKS_REQUIRED(!m_mutex);
      39                 :             : 
      40                 :             :     /** Compute and return the median of the collected time offset samples. The median is returned
      41                 :             :      * as 0 when there are less than 5 samples. */
      42                 :             :     std::chrono::seconds Median() const EXCLUSIVE_LOCKS_REQUIRED(!m_mutex);
      43                 :             : 
      44                 :             :     /** Raise warnings if the median time offset exceeds the warnings threshold. Returns true if
      45                 :             :      * warnings were raised. */
      46                 :             :     bool WarnIfOutOfSync() const EXCLUSIVE_LOCKS_REQUIRED(!m_mutex);
      47                 :             : };
      48                 :             : 
      49                 :             : #endif // BITCOIN_NODE_TIMEOFFSETS_H