lob0util.h

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#ifndef lob0util_h
#define lob0util_h
 
#include <stdint.h>
 
#include "buf0buf.h"
#include "fil0fil.h"
#include "fut0lst.h"
 
namespace lob {
 
/** Number of times an LOB can be partially updated.  Once this limit is
reached, then the LOB will be fully updated. */
const uint32_t MAX_PARTIAL_UPDATE_LIMIT = 1000;
 
struct basic_page_t {
  basic_page_t() : m_block(nullptr), m_mtr(nullptr), m_index(nullptr) {}
 
  basic_page_t(buf_block_t *block, mtr_t *mtr)
      : m_block(block), m_mtr(mtr), m_index(nullptr) {}
 
  basic_page_t(buf_block_t *block, mtr_t *mtr, dict_index_t *index)
      : m_block(block), m_mtr(mtr), m_index(index) {}
 
  /** Update the space identifier to given value without generating
  any redo log records.
  @param[in]    space_id        the space identifier. */
  void set_space_id_no_redo(space_id_t space_id) {
    mach_write_to_4(frame() + FIL_PAGE_SPACE_ID, space_id);
  }
 
  /** Get page number of the current page.
  @return the page number of the current page. */
  page_no_t get_page_no() const {
    ut_ad(m_block != nullptr);
    return (m_block->page.id.page_no());
  }
 
  /** Get the page id of the current page.
  @return the page id of current page. */
  page_id_t get_page_id() const {
    ut_ad(m_block != nullptr);
    return (m_block->page.id);
  }
 
  /** Set the FIL_PAGE_NEXT to the given page number, using the given mini
  transaction context.
  @param[in]    page_no   The page number to set.
  @param[in]    mtr       The mini-transaction context. */
  void set_next_page(page_no_t page_no, mtr_t *mtr) {
    mlog_write_ulint(frame() + FIL_PAGE_NEXT, page_no, MLOG_4BYTES, mtr);
  }
 
  /** Set the FIL_PAGE_NEXT to the given page number.
  @param[in]    page_no   The page number to set. */
  void set_next_page(page_no_t page_no) { set_next_page(page_no, m_mtr); }
 
  /** Set the FIL_PAGE_NEXT to FIL_NULL. */
  void set_next_page_null() {
    ut_ad(m_mtr != nullptr);
 
    set_next_page(FIL_NULL);
  }
 
  page_no_t get_next_page() {
    return (mach_read_from_4(frame() + FIL_PAGE_NEXT));
  }
 
  page_type_t get_page_type() const {
    return (mach_read_from_2(frame() + FIL_PAGE_TYPE));
  }
 
  byte *frame() const { return (buf_block_get_frame(m_block)); }
 
  flst_node_t *get_flst_node(const fil_addr_t &addr) {
    ut_ad(!addr.is_null());
 
    flst_node_t *node = nullptr;
    if (addr.page == get_page_no()) {
      node = frame() + addr.boffset;
    }
    return (node);
  }
 
  static ulint payload();
  ulint max_space_available();
 
  /** Get the underlying buffer block.
  @return the buffer block. */
  [[nodiscard]] buf_block_t *get_block() const noexcept;
 
  void set_block(buf_block_t *block) {
    ut_ad(mtr_memo_contains(m_mtr, block, MTR_MEMO_PAGE_X_FIX) ||
          mtr_memo_contains(m_mtr, block, MTR_MEMO_PAGE_S_FIX));
 
    m_block = block;
  }
 
  void set_mtr(mtr_t *mtr) { m_mtr = mtr; }
 
 protected:
  buf_block_t *m_block;
  mtr_t *m_mtr;
  dict_index_t *m_index;
};
 
[[nodiscard]] inline buf_block_t *basic_page_t::get_block() const noexcept {
  return m_block;
}
 
/** Allocate one LOB page.
@param[in]  index   Index in which LOB exists.
@param[in]  lob_mtr Mini-transaction context.
@param[in]  hint    Hint page number for allocation.
@param[in]  bulk    true if operation is OPCODE_INSERT_BULK,
                    false otherwise.
@return the allocated block of the BLOB page or nullptr. */
buf_block_t *alloc_lob_page(dict_index_t *index, mtr_t *lob_mtr, page_no_t hint,
                            bool bulk);
 
/** Check if the index entry is visible to the given transaction.
@param[in]      index           the index to which LOB belongs.
@param[in]      trx             the transaction reading the index entry.
@param[in]      entry_trx_id    the trx id in the index entry. */
bool entry_visible_to(dict_index_t *index, trx_t *trx, trx_id_t entry_trx_id);
 
} /* namespace lob */
 
#endif /* lob0util_h */