YugabyteDB (2.13.1.0-b60, 21121d69985fbf76aa6958d8f04a9bfa936293b5)

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// with the License.  You may obtain a copy of the License at

//

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

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// specific language governing permissions and limitations

// under the License.

//

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

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// Portions Copyright (c) YugaByte, Inc.

//

// 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

//

// http://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

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//

#include "yb/util/threadlocal.h"

#include "yb/gutil/once.h"

#include "yb/util/errno.h"

namespace yb {

namespace threadlocal {

namespace internal {

// One key used by the entire process to attach destructors on thread exit.

static pthread_key_t destructors_key;

// The above key must only be initialized once per process.

static GoogleOnceType once = GOOGLE_ONCE_INIT;

// Call all the destructors associated with all THREAD_LOCAL instances in this

// thread.

static void InvokeDestructors(void* t) {

  PerThreadDestructorList* d = reinterpret_cast<PerThreadDestructorList*>(t);

  while (d != nullptr) {

    d->destructor(d->arg);

    PerThreadDestructorList* next = d->next;

    delete d;

    d = next;

  }

}

// This key must be initialized only once.

static void CreateKey() {

  int ret = pthread_key_create(&destructors_key, &InvokeDestructors);

  // Linux supports up to 1024 keys, we will use only one for all thread locals.

  CHECK_EQ(0, ret) << "pthread_key_create() failed, cannot add destructor to thread: "

      << "error " << ret << ": " << ErrnoToString(ret);

}

// Adds a destructor to the list.

void AddDestructor(PerThreadDestructorList* p) {

  GoogleOnceInit(&once, &CreateKey);

  // Returns NULL if nothing is set yet.

  p->next = reinterpret_cast<PerThreadDestructorList*>(pthread_getspecific(destructors_key));

  int ret = pthread_setspecific(destructors_key, p);

  // The only time this check should fail is if we are out of memory, or if

  // somehow key creation failed, which should be caught by the above CHECK.

  CHECK_EQ(0, ret) << "pthread_setspecific() failed, cannot update destructor list: "

      << "error " << ret << ": " << ErrnoToString(ret);

}

} // namespace internal

} // namespace threadlocal

} // namespace yb