YugabyteDB (2.13.0.0-b42, bfc6a6643e7399ac8a0e81d06a3ee6d6571b33ab)

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//   http://www.apache.org/licenses/LICENSE-2.0

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// under the License.

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// The following only applies to changes made to this file as part of YugaByte development.

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// Portions Copyright (c) YugaByte, Inc.

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// 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

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// http://www.apache.org/licenses/LICENSE-2.0

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// Unless required by applicable law or agreed to in writing, software distributed under the License

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#include "yb/util/oid_generator.h"

#include <mutex>

#include <string>

#include <boost/uuid/uuid_generators.hpp>

#include "yb/gutil/strings/escaping.h"

#include "yb/util/cast.h"

#include "yb/util/locks.h"

#include "yb/util/thread.h"

namespace yb {

namespace {

class Generator {

 public:

  std::string Next(bool binary_id) {

    // Use the thread id to select a random oid generator.

    auto& entry = entries_[yb::Thread::UniqueThreadId() % kNumOidGenerators];

    boost::uuids::uuid oid;

    {

      std::lock_guard<LockType> lock(entry.lock);

      oid = entry.generator();

    }

    return binary_id ? string(to_char_ptr(oid.data), sizeof(oid.data))

                     : b2a_hex(to_char_ptr(oid.data), sizeof(oid.data));

  }

 private:

  typedef simple_spinlock LockType;

  // Multiple instances of OID generators with corresponding locks are used to

  // avoid bottlenecking on a single lock.

  static const int kNumOidGenerators = 17;

  struct Entry {

    LockType lock;

    boost::uuids::random_generator generator;

  };

  Entry entries_[kNumOidGenerators];

};

} // namespace

// Generates a unique 32byte id, based on uuid v4.

// This class is thread safe

std::string GenerateObjectId(bool binary_id) {

  static Generator generator;

  return generator.Next(binary_id);

}

} // namespace yb