rem0lrec.h

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/** @file include/rem0lrec.h
 Record manager.
 This file contains low level functions which deals with physical index of
 fields in a physical record.
 
 After INSTANT ADD/DROP feature, fields index on logical record might not be
 same as field index on physical record. So a wrapper (rem0wrec.h) is
 implemented which translates logical index to physical index. And then
 functions of this file are called with physical index of the field.
 
 Created 13/08/2021 Mayank Prasad
*****************************************************************************/
 
#ifndef rem0lrec_h
#define rem0lrec_h
 
#include "rem0rec.h"
 
/** Set nth field value to SQL NULL.
@param[in,out]  rec  record
@param[in]      n    index of the field. */
static inline void rec_set_nth_field_sql_null_low(rec_t *rec, ulint n);
 
/** Returns nonzero if the SQL NULL bit is set in nth field of rec.
@param[in]  offsets  array returned by rec_get_offsets()
@param[in]  n        index of the field.
@return nonzero if SQL NULL */
static inline ulint rec_offs_nth_sql_null_low(const ulint *offsets, ulint n);
 
/** Read the offset of the start of a data field in the record. The start of an
SQL null field is the end offset of the previous non-null field, or 0, if none
exists. If n is the number of the last field + 1, then the end offset of the
last field is returned.
@param[in]  rec  record
@param[in]  n    index of the field
@return offset of the start of the field */
static inline ulint rec_get_field_start_offs_low(const rec_t *rec, ulint n);
 
/** Returns the offset of nth field start if the record is stored in the 1-byte
offsets form.
@param[in]  rec  record
@param[in]  n    index of the field
@return offset of the start of the field */
static inline ulint rec_1_get_field_start_offs_low(const rec_t *rec, ulint n);
 
/** Returns the offset of nth field end if the record is stored in the 1-byte
offsets form. If the field is SQL null, the flag is ORed in the returned value.
@param[in]  rec  record
@param[in]  n    index of the field
@return offset of the start of the field, SQL null flag ORed */
static inline ulint rec_1_get_field_end_info_low(const rec_t *rec, ulint n);
 
/** Sets the field end info for the nth field if the record is stored in the
1-byte format.
@param[in,out]  rec   record
@param[in]      n     index of the field
@param[in]      info  value to set */
static inline void rec_1_set_field_end_info_low(rec_t *rec, ulint n,
                                                ulint info);
/** Returns the offset of nth field start if the record is stored in the 2-byte
offsets form.
@param[in]  rec   record
@param[in]  n     index of the field
@return offset of the start of the field */
static inline ulint rec_2_get_field_start_offs_low(const rec_t *rec, ulint n);
 
/** Returns the offset of nth field end if the record is stored in the 2-byte
offsets form. If the field is SQL null, the flag is ORed in the returned value.
@param[in]  rec   record
@param[in]  n     index of the field
@return offset of the start of the field, SQL null flag and extern storage flag
ORed */
static inline ulint rec_2_get_field_end_info_low(const rec_t *rec, ulint n);
 
/** Sets the field end info for the nth field if the record is stored in the
2-byte format.
@param[in]  rec   record
@param[in]  n     index of the field
@param[out] info  end info */
static inline void rec_2_set_field_end_info_low(rec_t *rec, ulint n,
                                                ulint info);
 
/** Sets the value of the ith field SQL null bit of an old-style record.
@param[in]  rec   record
@param[in]  i     index of the field
@param[in]  val   value to set */
static inline void rec_set_nth_field_null_bit_low(rec_t *rec, ulint i,
                                                  bool val);
 
/** Gets the physical size of an old-style field.
Also an SQL null may have a field of size > 0, if the data type is of a fixed
size.
@param[in]  rec   record
@param[in]  n     index of the field
@return field size in bytes */
static inline ulint rec_get_nth_field_size_low(const rec_t *rec, ulint n) {
  ulint os;
  ulint next_os;
 
  os = rec_get_field_start_offs_low(rec, n);
  next_os = rec_get_field_start_offs_low(rec, n + 1);
 
  ut_ad(next_os - os < UNIV_PAGE_SIZE);
 
  return (next_os - os);
}
 
/** The following function is used to get the offset to the nth
data field in an old-style record.
@param[in]   rec  record
@param[in]   n    index of the field
@param[out]  len  length of the field; UNIV_SQL_NULL if SQL null;
@return offset to the field */
static inline ulint rec_get_nth_field_offs_old_low(const rec_t *rec, ulint n,
                                                   ulint *len) {
  ulint os;
  ulint next_os;
 
  ut_ad(len);
  ut_a(rec);
  ut_a(n < rec_get_n_fields_old_raw(rec));
 
  if (rec_get_1byte_offs_flag(rec)) {
    os = rec_1_get_field_start_offs_low(rec, n);
 
    next_os = rec_1_get_field_end_info_low(rec, n);
 
    if (next_os & REC_1BYTE_SQL_NULL_MASK) {
      *len = UNIV_SQL_NULL;
 
      return (os);
    }
 
    next_os = next_os & ~REC_1BYTE_SQL_NULL_MASK;
  } else {
    os = rec_2_get_field_start_offs_low(rec, n);
 
    next_os = rec_2_get_field_end_info_low(rec, n);
 
    if (next_os & REC_2BYTE_SQL_NULL_MASK) {
      *len = UNIV_SQL_NULL;
 
      return (os);
    }
 
    next_os = next_os & ~(REC_2BYTE_SQL_NULL_MASK | REC_2BYTE_EXTERN_MASK);
  }
 
  *len = next_os - os;
 
  ut_ad(*len < UNIV_PAGE_SIZE);
 
  return (os);
}
 
/** Mark the nth field as externally stored.
@param[in]  offsets  array returned by rec_get_offsets()
@param[in]  n       index of the field */
static inline void rec_offs_make_nth_extern_low(ulint *offsets, const ulint n) {
  ut_ad(!rec_offs_nth_sql_null_low(offsets, n));
  rec_offs_base(offsets)[1 + n] |= REC_OFFS_EXTERNAL;
}
 
static inline ulint rec_offs_nth_sql_null_low(const ulint *offsets, ulint n) {
  return (rec_offs_base(offsets)[1 + n] & REC_OFFS_SQL_NULL);
}
 
/** Returns nonzero if the default bit is set in nth field of rec.
@param[in]  offsets  array returned by rec_get_offsets()
@param[in]  n        index of the field
@return nonzero if default bit is set */
static inline ulint rec_offs_nth_default_low(const ulint *offsets, ulint n) {
  return (rec_offs_base(offsets)[1 + n] & REC_OFFS_DEFAULT);
}
 
/** Gets the physical size of a field.
@param[in]  offsets array returned by rec_get_offsets()
@param[in]  n       index of the field
@return length of field */
static inline ulint rec_offs_nth_size_low(const ulint *offsets, ulint n) {
  if (!n) {
    return (rec_offs_base(offsets)[1 + n] & REC_OFFS_MASK);
  }
  return ((rec_offs_base(offsets)[1 + n] - rec_offs_base(offsets)[n]) &
          REC_OFFS_MASK);
}
 
/** This is used to modify the value of an already existing field in a record.
The previous value must have exactly the same size as the new value. If len
is UNIV_SQL_NULL then the field is treated as an SQL null.
For records in ROW_FORMAT=COMPACT (new-style records), len must not be
UNIV_SQL_NULL unless the field already is SQL null.
@param[in]  rec      record
@param[in]  offsets  array returned by rec_get_offsets()
@param[in]  n        index of the field
@param[in]  data     pointer to the data if not SQL null
@param[in]  len      length of the data or UNIV_SQL_NULL */
static inline void rec_set_nth_field_low(rec_t *rec, const ulint *offsets,
                                         ulint n, const void *data, ulint len) {
  byte *data2;
  ulint len2;
 
  ut_ad(rec);
  ut_ad(rec_offs_validate(rec, nullptr, offsets));
 
  auto fn = [&](const ulint *offsets, ulint n) {
    ulint n_drop = 0;
    for (size_t i = 0; i < n; i++) {
      ulint len = rec_offs_base(offsets)[1 + i];
      if (len & REC_OFFS_DROP) {
        n_drop++;
      }
    }
    return n_drop;
  };
 
  if (len == UNIV_SQL_NULL) {
    if (!rec_offs_nth_sql_null_low(offsets, n)) {
      ut_a(!rec_offs_comp(offsets));
      ulint n_drop = rec_old_is_versioned(rec) ? fn(offsets, n) : 0;
      rec_set_nth_field_sql_null_low(rec, n - n_drop);
    }
 
    return;
  }
 
  ut_ad(!rec_offs_nth_default_low(offsets, n));
 
  /* nullptr for index as n is physical here */
  data2 = rec_get_nth_field(nullptr, rec, offsets, n, &len2);
 
  if (len2 == UNIV_SQL_NULL) {
    ut_ad(!rec_offs_comp(offsets));
    ulint n_drop = rec_old_is_versioned(rec) ? fn(offsets, n) : 0;
    rec_set_nth_field_null_bit_low(rec, n - n_drop, false);
    ut_ad(len == rec_get_nth_field_size_low(rec, n - n_drop));
  } else {
    ut_ad(len2 == len);
  }
 
  ut_memcpy(data2, data, len);
}
 
static inline void rec_set_nth_field_sql_null_low(rec_t *rec, ulint n) {
  ulint offset;
 
  offset = rec_get_field_start_offs_low(rec, n);
 
  data_write_sql_null(rec + offset, rec_get_nth_field_size_low(rec, n));
 
  rec_set_nth_field_null_bit_low(rec, n, true);
}
 
static inline void rec_set_nth_field_null_bit_low(rec_t *rec, ulint i,
                                                  bool val) {
  ulint info;
 
  if (rec_get_1byte_offs_flag(rec)) {
    info = rec_1_get_field_end_info_low(rec, i);
 
    if (val) {
      info = info | REC_1BYTE_SQL_NULL_MASK;
    } else {
      info = info & ~REC_1BYTE_SQL_NULL_MASK;
    }
 
    rec_1_set_field_end_info_low(rec, i, info);
 
    return;
  }
 
  info = rec_2_get_field_end_info_low(rec, i);
 
  if (val) {
    info = info | REC_2BYTE_SQL_NULL_MASK;
  } else {
    info = info & ~REC_2BYTE_SQL_NULL_MASK;
  }
 
  rec_2_set_field_end_info_low(rec, i, info);
}
 
static inline ulint rec_get_field_start_offs_low(const rec_t *rec, ulint n) {
  ut_ad(rec);
  ut_ad(n <= rec_get_n_fields_old_raw(rec));
 
  if (n == 0) {
    return (0);
  }
 
  if (rec_get_1byte_offs_flag(rec)) {
    return (rec_1_get_field_start_offs_low(rec, n));
  }
 
  return (rec_2_get_field_start_offs_low(rec, n));
}
 
static inline ulint rec_1_get_field_start_offs_low(const rec_t *rec, ulint n) {
  ut_ad(rec_get_1byte_offs_flag(rec));
  ut_ad(n <= rec_get_n_fields_old_raw(rec));
 
  if (n == 0) {
    return (0);
  }
 
  return (rec_1_get_prev_field_end_info(rec, n) & ~REC_1BYTE_SQL_NULL_MASK);
}
 
static inline ulint rec_2_get_field_start_offs_low(const rec_t *rec, ulint n) {
  ut_ad(!rec_get_1byte_offs_flag(rec));
  ut_ad(n <= rec_get_n_fields_old_raw(rec));
 
  if (n == 0) {
    return (0);
  }
 
  return (rec_2_get_prev_field_end_info(rec, n) &
          ~(REC_2BYTE_SQL_NULL_MASK | REC_2BYTE_EXTERN_MASK));
}
 
static inline ulint rec_1_get_field_end_info_low(const rec_t *rec, ulint n) {
  ut_ad(rec_get_1byte_offs_flag(rec));
  ut_ad(n < rec_get_n_fields_old_raw(rec));
 
  uint32_t version_size = 0;
  if (rec_old_is_versioned(rec)) {
    version_size = 1;
  }
 
  return (
      mach_read_from_1(rec - (REC_N_OLD_EXTRA_BYTES + version_size + n + 1)));
}
 
static inline ulint rec_2_get_field_end_info_low(const rec_t *rec, ulint n) {
  ut_ad(!rec_get_1byte_offs_flag(rec));
  ut_ad(n < rec_get_n_fields_old_raw(rec));
 
  uint32_t version_size = 0;
  if (rec_old_is_versioned(rec)) {
    version_size = 1;
  }
 
  return (mach_read_from_2(rec -
                           (REC_N_OLD_EXTRA_BYTES + version_size + 2 * n + 2)));
}
 
static inline void rec_1_set_field_end_info_low(rec_t *rec, ulint n,
                                                ulint info) {
  ut_ad(rec_get_1byte_offs_flag(rec));
  ut_ad(n < rec_get_n_fields_old_raw(rec));
 
  uint32_t version_length = 0;
  if (rec_old_is_versioned(rec)) {
    version_length = 1;
  }
 
  mach_write_to_1(rec - (REC_N_OLD_EXTRA_BYTES + version_length + n + 1), info);
}
 
static inline void rec_2_set_field_end_info_low(rec_t *rec, ulint n,
                                                ulint info) {
  ut_ad(!rec_get_1byte_offs_flag(rec));
  ut_ad(n < rec_get_n_fields_old_raw(rec));
 
  uint32_t version_length = 0;
  if (rec_old_is_versioned(rec)) {
    version_length = 1;
  }
 
  mach_write_to_2(rec - (REC_N_OLD_EXTRA_BYTES + version_length + 2 * n + 2),
                  info);
}
 
#endif