polardbxengine/storage/innobase/include/mem0mem.ic

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*****************************************************************************/

/** @file include/mem0mem.ic
 The memory management

 Created 6/8/1994 Heikki Tuuri
 *************************************************************************/

#include "ut0new.h"

#ifdef UNIV_DEBUG
#define mem_heap_create_block(heap, n, type, file_name, line) \
  mem_heap_create_block_func(heap, n, file_name, line, type)
#define mem_heap_create_at(N, file_name, line) \
  mem_heap_create_func(N, file_name, line, MEM_HEAP_DYNAMIC)
#else /* UNIV_DEBUG */
#define mem_heap_create_block(heap, n, type, file_name, line) \
  mem_heap_create_block_func(heap, n, type)
#define mem_heap_create_at(N, file_name, line) \
  mem_heap_create_func(N, MEM_HEAP_DYNAMIC)
#endif /* UNIV_DEBUG */
/** Creates a memory heap block where data can be allocated.
 @return own: memory heap block, NULL if did not succeed (only possible
 for MEM_HEAP_BTR_SEARCH type heaps) */
mem_block_t *mem_heap_create_block_func(
    mem_heap_t *heap, /*!< in: memory heap or NULL if first block
                      should be created */
    ulint n,          /*!< in: number of bytes needed for user data */
#ifdef UNIV_DEBUG
    const char *file_name, /*!< in: file name where created */
    ulint line,            /*!< in: line where created */
#endif                     /* UNIV_DEBUG */
    ulint type);           /*!< in: type of heap: MEM_HEAP_DYNAMIC or
                           MEM_HEAP_BUFFER */

/** Frees a block from a memory heap. */
void mem_heap_block_free(mem_heap_t *heap,    /*!< in: heap */
                         mem_block_t *block); /*!< in: block to free */

#ifndef UNIV_HOTBACKUP
#ifndef UNIV_LIBRARY
/** Frees the free_block field from a memory heap. */
void mem_heap_free_block_free(mem_heap_t *heap); /*!< in: heap */
#endif                                           /* !UNIV_LIBRARY */
#endif                                           /* !UNIV_HOTBACKUP */

/** Adds a new block to a memory heap.
 @param[in]	heap	memory heap
 @param[in]	n	number of bytes needed
 @return created block, NULL if did not succeed (only possible for
 MEM_HEAP_BTR_SEARCH type heaps) */
mem_block_t *mem_heap_add_block(mem_heap_t *heap, ulint n);

UNIV_INLINE
void mem_block_set_len(mem_block_t *block, ulint len) {
  ut_ad(len > 0);

  block->len = len;
}

UNIV_INLINE
ulint mem_block_get_len(mem_block_t *block) { return (block->len); }

UNIV_INLINE
void mem_block_set_type(mem_block_t *block, ulint type) {
  ut_ad((type == MEM_HEAP_DYNAMIC) || (type == MEM_HEAP_BUFFER) ||
        (type == MEM_HEAP_BUFFER + MEM_HEAP_BTR_SEARCH));

  block->type = type;
}

UNIV_INLINE
ulint mem_block_get_type(mem_block_t *block) { return (block->type); }

UNIV_INLINE
void mem_block_set_free(mem_block_t *block, ulint free) {
  ut_ad(free >= block->start);
  ut_ad(free <= mem_block_get_len(block));

  block->free = free;
}

UNIV_INLINE
ulint mem_block_get_free(mem_block_t *block) { return (block->free); }

UNIV_INLINE
void mem_block_set_start(mem_block_t *block, ulint start) {
  ut_ad(start > 0);

  block->start = start;
}

UNIV_INLINE
ulint mem_block_get_start(mem_block_t *block) { return (block->start); }

/** Checks that an object is a memory heap block
@param[in]	block	Memory block to check. */
UNIV_INLINE
void mem_block_validate(const mem_block_t *block) {
  if (block->magic_n != MEM_BLOCK_MAGIC_N) {
    ib::fatal error;
    error << "Memory block is invalid (correctness field value"
             " should be "
          << MEM_BLOCK_MAGIC_N << ", but it is " << block->magic_n
          << ") in a block of size " << block->len;
    ut_d(error << ", allocated at " << block->file_name << ":" << block->line);
  }
}

/** Allocates and zero-fills n bytes of memory from a memory heap.
@param[in]	heap	memory heap
@param[in]	n	number of bytes; if the heap is allowed to grow into
the buffer pool, this must be <= MEM_MAX_ALLOC_IN_BUF
@return allocated, zero-filled storage */
UNIV_INLINE
void *mem_heap_zalloc(mem_heap_t *heap, ulint n) {
  ut_ad(heap);
  ut_ad(!(heap->type & MEM_HEAP_BTR_SEARCH));
  return (memset(mem_heap_alloc(heap, n), 0, n));
}

/** Allocates n bytes of memory from a memory heap.
@param[in]	heap	memory heap
@param[in]	n	number of bytes; if the heap is allowed to grow into
the buffer pool, this must be <= MEM_MAX_ALLOC_IN_BUF
@return allocated storage, NULL if did not succeed (only possible for
MEM_HEAP_BTR_SEARCH type heaps) */
UNIV_INLINE
void *mem_heap_alloc(mem_heap_t *heap, ulint n) {
  mem_block_t *block;
  byte *buf;
  ulint free;

  ut_d(mem_block_validate(heap));

  block = UT_LIST_GET_LAST(heap->base);

  ut_ad(!(block->type & MEM_HEAP_BUFFER) || (n <= MEM_MAX_ALLOC_IN_BUF));

  /* Check if there is enough space in block. If not, create a new
  block to the heap */

  if (mem_block_get_len(block) <
      mem_block_get_free(block) + MEM_SPACE_NEEDED(n)) {
    block = mem_heap_add_block(heap, n);

    if (block == NULL) {
      return (NULL);
    }
  }

  free = mem_block_get_free(block);

  buf = (byte *)block + free + MEM_NO_MANS_LAND;

  mem_block_set_free(block, free + MEM_SPACE_NEEDED(n));

  ut_ad(mem_block_get_len(block) >= mem_block_get_free(block));

  UNIV_MEM_ALLOC(buf - MEM_NO_MANS_LAND, MEM_SPACE_NEEDED(n));

#ifdef UNIV_DEBUG
  byte *start_no_mans_land = buf - MEM_NO_MANS_LAND;
  byte *end_no_mans_land =
      start_no_mans_land + MEM_SPACE_NEEDED(n) - MEM_NO_MANS_LAND;
  memset(start_no_mans_land, MEM_NO_MANS_LAND_BEFORE_BYTE, MEM_NO_MANS_LAND);
  UNIV_MEM_FREE(start_no_mans_land, MEM_NO_MANS_LAND);

  memset(end_no_mans_land, MEM_NO_MANS_LAND_AFTER_BYTE, MEM_NO_MANS_LAND);
  UNIV_MEM_FREE(end_no_mans_land, MEM_NO_MANS_LAND);
#endif

  return (buf);
}

#ifdef UNIV_DEBUG
UNIV_INLINE
void validate_no_mans_land(byte *no_mans_land_begin,
                           byte mem_no_mans_land_byte) {
  UNIV_MEM_VALID(no_mans_land_begin, MEM_NO_MANS_LAND);
  for (byte *no_mans_land_it = no_mans_land_begin;
       no_mans_land_it < no_mans_land_begin + MEM_NO_MANS_LAND;
       ++no_mans_land_it) {
    ut_a(*no_mans_land_it == mem_no_mans_land_byte);
  }
}
#endif

/** Returns a pointer to the heap top.
@param[in]	heap	memory heap
@return pointer to the heap top */
UNIV_INLINE
byte *mem_heap_get_heap_top(mem_heap_t *heap) {
  mem_block_t *block;
  byte *buf;

  ut_d(mem_block_validate(heap));

  block = UT_LIST_GET_LAST(heap->base);

  buf = (byte *)block + mem_block_get_free(block);

  return (buf);
}

/** Frees the space in a memory heap exceeding the pointer given.
The pointer must have been acquired from mem_heap_get_heap_top.
The first memory block of the heap is not freed.
@param[in]	heap		heap from which to free
@param[in]	old_top		pointer to old top of heap */
UNIV_INLINE
void mem_heap_free_heap_top(mem_heap_t *heap, byte *old_top) {
  mem_block_t *block;
  mem_block_t *prev_block;

  ut_d(mem_heap_validate(heap));

  block = UT_LIST_GET_LAST(heap->base);

  while (block != NULL) {
    if (((byte *)block + mem_block_get_free(block) >= old_top) &&
        ((byte *)block <= old_top)) {
      /* Found the right block */

      break;
    }

    /* Store prev_block value before freeing the current block
    (the current block will be erased in freeing) */

    prev_block = UT_LIST_GET_PREV(list, block);

    mem_heap_block_free(heap, block);

    block = prev_block;
  }

  ut_ad(block);

  if (old_top == (byte *)block + mem_block_get_free(block)) {
    return;
  }

#ifdef UNIV_DEBUG
  validate_no_mans_land(old_top, MEM_NO_MANS_LAND_BEFORE_BYTE);
  validate_no_mans_land(
      (byte *)block + mem_block_get_free(block) - MEM_NO_MANS_LAND,
      MEM_NO_MANS_LAND_AFTER_BYTE);
#endif
  /* Set the free field of block */
  mem_block_set_free(block, old_top - (byte *)block);

  ut_ad(mem_block_get_start(block) <= mem_block_get_free(block));
  UNIV_MEM_FREE(old_top, (byte *)block + block->len - old_top);

  /* If free == start, we may free the block if it is not the first
  one */

  if ((heap != block) &&
      (mem_block_get_free(block) == mem_block_get_start(block))) {
    mem_heap_block_free(heap, block);
  }
}

/** Empties a memory heap.
The first memory block of the heap is not freed.
@param[in]	heap	heap to empty */
UNIV_INLINE
void mem_heap_empty(mem_heap_t *heap) {
  mem_heap_free_heap_top(heap, (byte *)heap + mem_block_get_start(heap));
#ifndef UNIV_HOTBACKUP
#ifndef UNIV_LIBRARY
  if (heap->free_block) {
    mem_heap_free_block_free(heap);
  }
#endif /* !UNIV_LIBRARY */
#endif /* !UNIV_HOTBACKUP */
}

/** Returns a pointer to the topmost element in a memory heap.
The size of the element must be given.
@param[in]	heap	memory heap
@param[in]	n	size of the topmost element
@return pointer to the topmost element */
UNIV_INLINE
void *mem_heap_get_top(mem_heap_t *heap, ulint n) {
  mem_block_t *block;
  byte *buf;

  ut_d(mem_block_validate(heap));

  block = UT_LIST_GET_LAST(heap->base);

  buf = (byte *)block + mem_block_get_free(block) - MEM_SPACE_NEEDED(n) +
        MEM_NO_MANS_LAND;

  return ((void *)buf);
}

/** Checks if a given chunk of memory is the topmost element stored in the
heap. If this is the case, then calling mem_heap_free_top() would free
that element from the heap.
@param[in]	heap	memory heap
@param[in]	buf	presumed topmost element
@param[in]	buf_sz	size of buf in bytes
@return true if topmost */
UNIV_INLINE
bool mem_heap_is_top(mem_heap_t *heap, const void *buf, ulint buf_sz) {
  const byte *first_free_byte;
  const byte *presumed_start_of_buf;

  ut_d(mem_block_validate(heap));

  first_free_byte = mem_heap_get_heap_top(heap);

  presumed_start_of_buf =
      first_free_byte - MEM_SPACE_NEEDED(buf_sz) + MEM_NO_MANS_LAND;

  return (presumed_start_of_buf == buf);
}

/** Allocate a new chunk of memory from a memory heap, possibly discarding
 the topmost element. If the memory chunk specified with (top, top_sz)
 is the topmost element, then it will be discarded, otherwise it will
 be left untouched and this function will be equivallent to
 mem_heap_alloc().
 @return allocated storage, NULL if did not succeed (only possible for
 MEM_HEAP_BTR_SEARCH type heaps) */
UNIV_INLINE
void *mem_heap_replace(mem_heap_t *heap, /*!< in/out: memory heap */
                       const void *top, /*!< in: chunk to discard if possible */
                       ulint top_sz,    /*!< in: size of top in bytes */
                       ulint new_sz) /*!< in: desired size of the new chunk */
{
  if (mem_heap_is_top(heap, top, top_sz)) {
    mem_heap_free_top(heap, top_sz);
  }

  return (mem_heap_alloc(heap, new_sz));
}

/** Allocate a new chunk of memory from a memory heap, possibly discarding
 the topmost element and then copy the specified data to it. If the memory
 chunk specified with (top, top_sz) is the topmost element, then it will be
 discarded, otherwise it will be left untouched and this function will be
 equivallent to mem_heap_dup().
 @return allocated storage, NULL if did not succeed (only possible for
 MEM_HEAP_BTR_SEARCH type heaps) */
UNIV_INLINE
void *mem_heap_dup_replace(
    mem_heap_t *heap, /*!< in/out: memory heap */
    const void *top,  /*!< in: chunk to discard if possible */
    ulint top_sz,     /*!< in: size of top in bytes */
    const void *data, /*!< in: new data to duplicate */
    ulint data_sz)    /*!< in: size of data in bytes */
{
  void *p = mem_heap_replace(heap, top, top_sz, data_sz);

  memcpy(p, data, data_sz);

  return (p);
}

/** Allocate a new chunk of memory from a memory heap, possibly discarding
 the topmost element and then copy the specified string to it. If the memory
 chunk specified with (top, top_sz) is the topmost element, then it will be
 discarded, otherwise it will be left untouched and this function will be
 equivallent to mem_heap_strdup().
 @return allocated string, NULL if did not succeed (only possible for
 MEM_HEAP_BTR_SEARCH type heaps) */
UNIV_INLINE
char *mem_heap_strdup_replace(
    mem_heap_t *heap, /*!< in/out: memory heap */
    const void *top,  /*!< in: chunk to discard if possible */
    ulint top_sz,     /*!< in: size of top in bytes */
    const char *str)  /*!< in: new data to duplicate */
{
  return (reinterpret_cast<char *>(
      mem_heap_dup_replace(heap, top, top_sz, str, strlen(str) + 1)));
}

/** Frees the topmost element in a memory heap. The size of the element must be
 given. */
UNIV_INLINE
void mem_heap_free_top(mem_heap_t *heap, /*!< in: memory heap */
                       ulint n)          /*!< in: size of the topmost element */
{
  mem_block_t *block;

  ut_d(mem_block_validate(heap));

  block = UT_LIST_GET_LAST(heap->base);

  /* Subtract the free field of block */
  mem_block_set_free(block, mem_block_get_free(block) - MEM_SPACE_NEEDED(n));
  UNIV_MEM_ASSERT_W(
      (byte *)block + mem_block_get_free(block) + MEM_NO_MANS_LAND, n);
#ifdef UNIV_DEBUG
  validate_no_mans_land((byte *)block + mem_block_get_free(block),
                        MEM_NO_MANS_LAND_BEFORE_BYTE);
  validate_no_mans_land((byte *)block + mem_block_get_free(block) +
                            MEM_SPACE_NEEDED(n) - MEM_NO_MANS_LAND,
                        MEM_NO_MANS_LAND_AFTER_BYTE);
#endif

  /* If free == start, we may free the block if it is not the first
  one */

  if ((heap != block) &&
      (mem_block_get_free(block) == mem_block_get_start(block))) {
    mem_heap_block_free(heap, block);
  } else {
    UNIV_MEM_FREE((byte *)block + mem_block_get_free(block),
                  MEM_SPACE_NEEDED(n));
  }
}

/** Creates a memory heap.
NOTE: Use the corresponding macros instead of this function.
A single user buffer of 'size' will fit in the block.
0 creates a default size block.
@param[in]	size		Desired start block size.
@param[in]	file_name	File name where created
@param[in]	line		Line where created
@param[in]	type		Heap type
@return own: memory heap, NULL if did not succeed (only possible for
MEM_HEAP_BTR_SEARCH type heaps) */
UNIV_INLINE
mem_heap_t *mem_heap_create_func(ulint size,
#ifdef UNIV_DEBUG
                                 const char *file_name, ulint line,
#endif /* UNIV_DEBUG */
                                 ulint type) {
  mem_block_t *block;

  if (!size) {
    size = MEM_BLOCK_START_SIZE;
  }

  block = mem_heap_create_block(NULL, size, type, file_name, line);

  if (block == NULL) {
    return (NULL);
  }

#ifndef UNIV_HOTBACKUP
#ifndef UNIV_LIBRARY
  /* The first block should not be in buffer pool,
  because it might be relocated to resize buffer pool. */
  ut_ad(block->buf_block == NULL);
#endif /* !UNIV_LIBRARY */
#endif /* UNIV_HOTBACKUP */

  UT_LIST_INIT(block->base, &mem_block_t::list);

  /* Add the created block itself as the first block in the list */
  UT_LIST_ADD_FIRST(block->base, block);

  return (block);
}

/** Frees the space occupied by a memory heap.
NOTE: Use the corresponding macro instead of this function.
@param[in]	heap	Heap to be freed */
UNIV_INLINE
void mem_heap_free(mem_heap_t *heap) {
  mem_block_t *block;
  mem_block_t *prev_block;

  ut_d(mem_block_validate(heap));

  block = UT_LIST_GET_LAST(heap->base);

#ifndef UNIV_HOTBACKUP
#ifndef UNIV_LIBRARY
  if (heap->free_block) {
    mem_heap_free_block_free(heap);
  }
#endif /* !UNIV_LIBRARY */
#endif /* !UNIV_HOTBACKUP */

  while (block != NULL) {
    /* Store the contents of info before freeing current block
    (it is erased in freeing) */

    prev_block = UT_LIST_GET_PREV(list, block);

    mem_heap_block_free(heap, block);

    block = prev_block;
  }
}

/** Returns the space in bytes occupied by a memory heap. */
UNIV_INLINE
ulint mem_heap_get_size(mem_heap_t *heap) /*!< in: heap */
{
  ulint size = 0;

  ut_d(mem_block_validate(heap));

  size = heap->total_size;

#ifndef UNIV_LIBRARY
  if (heap->free_block) {
    size += UNIV_PAGE_SIZE;
  }
#endif /* !UNIV_LIBRARY */

  return (size);
}

/** Duplicates a NUL-terminated string.
 @return own: a copy of the string, must be deallocated with ut_free */
UNIV_INLINE
char *mem_strdup(const char *str) /*!< in: string to be copied */
{
  ulint len = strlen(str) + 1;
  return (static_cast<char *>(memcpy(ut_malloc_nokey(len), str, len)));
}

/** Makes a NUL-terminated copy of a nonterminated string.
 @return own: a copy of the string, must be deallocated with ut_free */
UNIV_INLINE
char *mem_strdupl(const char *str, /*!< in: string to be copied */
                  ulint len)       /*!< in: length of str, in bytes */
{
  char *s = static_cast<char *>(ut_malloc_nokey(len + 1));
  s[len] = 0;
  if (len > 0) {
    memcpy(s, str, len);
  }
  return s;
}

/** Makes a NUL-terminated copy of a nonterminated string,
 allocated from a memory heap.
 @return own: a copy of the string */
UNIV_INLINE
char *mem_heap_strdupl(
    mem_heap_t *heap, /*!< in: memory heap where string is allocated */
    const char *str,  /*!< in: string to be copied */
    ulint len)        /*!< in: length of str, in bytes */
{
  char *s = (char *)mem_heap_alloc(heap, len + 1);
  s[len] = 0;
  if (len > 0) {
    memcpy(s, str, len);
  }
  return s;
}