src/common/index-allocator.h

   1 /*
   2  * Copyright (C) 2020 Francis Deslauriers <francis.deslauriers@efficios.com>
   3  *
   4  * SPDX-License-Identifier: GPL-2.0-only
   5  *
   6  */
   7
   8 #ifndef _COMMON_INDEX_ALLOCATOR_H
   9 #define _COMMON_INDEX_ALLOCATOR_H
  10
  11 #include <inttypes.h>
  12 #include <lttng/lttng-export.h>
  13
  14 struct lttng_index_allocator;
  15
  16 enum lttng_index_allocator_status {
  17         LTTNG_INDEX_ALLOCATOR_STATUS_OK,
  18         LTTNG_INDEX_ALLOCATOR_STATUS_EMPTY,
  19         LTTNG_INDEX_ALLOCATOR_STATUS_ERROR,
  20 };
  21
  22 /*
  23  * Create an index allocator of `index_count` slots.
  24  */
  25 extern "C" LTTNG_EXPORT
  26 struct lttng_index_allocator *lttng_index_allocator_create(
  27                 uint64_t index_count);
  28
  29 /*
  30  * Get the number of indexes currently in use.
  31  */
  32 extern "C" LTTNG_EXPORT
  33 uint64_t lttng_index_allocator_get_index_count(
  34         struct lttng_index_allocator *allocator);
  35
  36 /*
  37  * Allocate (i.e. reserve) a slot.
  38  */
  39 extern "C" LTTNG_EXPORT
  40 enum lttng_index_allocator_status lttng_index_allocator_alloc(
  41                 struct lttng_index_allocator *allocator,
  42                 uint64_t *index);
  43
  44 /*
  45  * Release a slot by index. The slot will be re-used by the index allocator
  46  * in future 'alloc' calls.
  47  */
  48 extern "C" LTTNG_EXPORT
  49 enum lttng_index_allocator_status lttng_index_allocator_release(
  50                 struct lttng_index_allocator *allocator, uint64_t index);
  51
  52 /*
  53  * Destroy an index allocator.
  54  */
  55 extern "C" LTTNG_EXPORT
  56 void lttng_index_allocator_destroy(struct lttng_index_allocator *allocator);
  57
  58 #endif /* _COMMON_INDEX_ALLOCATOR_H */