lob0zip.h

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#ifndef lob0zip_h
#define lob0zip_h
 
#include "lob0ins.h"
 
namespace lob {
 
/** Insert or write the compressed BLOB as a single zlib stream. */
class zInserter : private BaseInserter {
 public:
  /** Constructor.
  @param[in]    ctx     blob operation context. */
  zInserter(InsertContext *ctx) : BaseInserter(ctx), m_heap(nullptr) {}
 
  /** Destructor. */
  ~zInserter();
 
  /** Prepare to write a compressed BLOB. Setup the zlib
  compression stream.
  @return DB_SUCCESS on success, error code on failure. */
  dberr_t prepare();
 
  /** Write all the BLOBs of the clustered index record.
  @return DB_SUCCESS on success, error code on failure. */
  dberr_t write();
 
  /** Write one blob field data.
  @param[in]    blob_j  the blob field number
  @return DB_SUCCESS on success, error code on failure. */
  dberr_t write_one_blob(size_t blob_j);
 
  /** Cleanup after completing the write of compressed BLOB.
  @param[in]    validate        if true, validate all the
                                  lob references. if false,
                                  skip this validation.
  @return DB_SUCCESS on success, error code on failure. */
  dberr_t finish(bool validate = true) {
    int ret = deflateEnd(&m_stream);
    ut_ad(ret == Z_OK);
    ut_ad(!validate || validate_blobrefs());
 
    if (ret != Z_OK) {
      m_err = DB_FAIL;
    }
    return (m_err);
  }
 
  /** Write the page type of the BLOB page and also generate the
  redo log record.
  @param[in]    blob_page       the BLOB page
  @param[in]    nth_blob_page   the count of BLOB page from
                                  the beginning of the BLOB. */
  void log_page_type(page_t *blob_page, ulint nth_blob_page) {
    page_type_t page_type;
 
    if (is_index_sdi()) {
      page_type = FIL_PAGE_SDI_ZBLOB;
    } else if (nth_blob_page == 0) {
      page_type = FIL_PAGE_TYPE_ZBLOB;
    } else {
      page_type = FIL_PAGE_TYPE_ZBLOB2;
    }
 
    mlog_write_ulint(blob_page + FIL_PAGE_TYPE, page_type, MLOG_2BYTES,
                     &m_blob_mtr);
  }
 
  /** Calculate the total number of pages needed to store
  the given blobs */
  ulint calc_total_pages() {
    const page_size_t page_size = m_ctx->page_size();
 
    /* Space available in compressed page to carry blob data */
    const ulint payload_size_zip = page_size.physical() - FIL_PAGE_DATA;
 
    const big_rec_t *vec = m_ctx->get_big_rec_vec();
 
    ulint total_blob_pages = 0;
    for (ulint i = 0; i < vec->n_fields; i++) {
      total_blob_pages +=
          static_cast<ulint>(
              deflateBound(&m_stream, static_cast<uLong>(vec->fields[i].len)) +
              payload_size_zip - 1) /
          payload_size_zip;
    }
 
    return (total_blob_pages);
  }
 
  /** Write contents into a single BLOB page.
  @return code as returned by zlib. */
  int write_into_single_page();
 
  /** Commit the BLOB mtr. */
  void commit_blob_mtr() { mtr_commit(&m_blob_mtr); }
 
  /** Write one blob page.  This function will be repeatedly called
  with an increasing nth_blob_page to completely write a BLOB.
  @param[in]    field           the big record field.
  @param[in]    nth_blob_page   count of the BLOB page (starting from 1).
  @return code as returned by the zlib. */
  int write_single_blob_page(big_rec_field_t &field, ulint nth_blob_page);
 
  /** Write first blob page.
  @param[in]    field           the big record field.
  @return code as returned by the zlib. */
  int write_first_page(big_rec_field_t &field);
 
  /** Verify that all pointers to externally stored columns in the record
  is be valid.  If validation fails, this function doesn't return.
  @return true if valid. */
  bool validate_blobrefs() const {
    const ulint *offsets = m_ctx->get_offsets();
 
    for (ulint i = 0; i < rec_offs_n_fields(offsets); i++) {
      if (!rec_offs_nth_extern(m_ctx->index(), offsets, i)) {
        continue;
      }
 
      byte *field_ref =
          btr_rec_get_field_ref(m_ctx->index(), m_ctx->rec(), offsets, i);
 
      ref_t blobref(field_ref);
 
      /* The pointer must not be zero if the operation
      succeeded. */
      ut_a(!blobref.is_null() || m_err != DB_SUCCESS);
 
      /* The column must not be disowned by this record. */
      ut_a(blobref.is_owner());
    }
    return (true);
  }
 
  /** For the given blob field, update its length in the blob reference
  which is available in the clustered index record.
  @param[in]    field   the concerned blob field. */
  void update_length_in_blobref(big_rec_field_t &field);
 
  /** Make the current page as next page of previous page.  In other
  words, make the page m_cur_blob_page_no as the next page
  (FIL_PAGE_NEXT) of page m_prev_page_no.
  @return DB_SUCCESS on success, or error code on failure. */
  dberr_t set_page_next();
 
  /** Write one small blob field data. Refer to ref_t to determine
  the definition of small blob.
  @param[in]    blob_j  the blob field number
  @return DB_SUCCESS on success, error code on failure. */
  dberr_t write_one_small_blob(size_t blob_j);
 
 private:
  /** Add the BLOB page information to the directory
  @param[in]    page_info       BLOB page information. */
  void add_to_blob_dir(const blob_page_info_t &page_info) {
    m_dir.add(page_info);
  }
 
  mem_heap_t *m_heap;
  z_stream m_stream;
 
  /** The BLOB directory information. */
  blob_dir_t m_dir;
};
 
inline zInserter::~zInserter() {
  if (m_heap != nullptr) {
    mem_heap_free(m_heap);
  }
}
 
}  // namespace lob
 
#endif  // lob0zip_h