/* Copyright (c) 2000, 2021, Oracle and/or its affiliates. All rights
 * reserved.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License, version 2.0,
   as published by the Free Software Foundation.

   This program is also distributed with certain software (including
   but not limited to OpenSSL) that is licensed under separate terms,
   as designated in a particular file or component or in included license
   documentation.  The authors of MySQL hereby grant you an additional
   permission to link the program and your derivative works with the
   separately licensed software that they have included with MySQL.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License, version 2.0, for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301  USA */

#include "my_global.h"                          // HAVE_*

#include <mysql.h>
#include "emb_qcache.h"
#include "embedded_priv.h"
#include "sql_class.h"                          // THD

void Querycache_stream::store_uchar(uchar c)
{
  if (data_end == cur_data)
    use_next_block(TRUE);
  *(cur_data++)= c;
#ifndef NDEBUG
  stored_size++;
#endif
}

void Querycache_stream::store_short(ushort s)
{
#ifndef NDEBUG
  stored_size+= 2;
#endif
  if (data_end - cur_data > 1)
  {
    int2store(cur_data, s);
    cur_data+= 2;
    return;
  }
  if (data_end == cur_data)
  {
    use_next_block(TRUE);
    int2store(cur_data, s);
    cur_data+= 2;
    return;
  }
  *cur_data= ((uchar *)(&s))[0];
  use_next_block(TRUE);
  *(cur_data++)= ((uchar *)(&s))[1];
}

void Querycache_stream::store_int(uint i)
{
#ifndef NDEBUG
  stored_size+= 4;
#endif
  size_t rest_len= data_end - cur_data;
  if (rest_len > 3)
  {
    int4store(cur_data, i);
    cur_data+= 4;
    return;
  }
  if (!rest_len)
  {
    use_next_block(TRUE);
    int4store(cur_data, i);
    cur_data+= 4;
    return;
  }
  char buf[4];
  int4store(buf, i);
  memcpy(cur_data, buf, rest_len);
  use_next_block(TRUE);
  memcpy(cur_data, buf+rest_len, 4-rest_len);
  cur_data+= 4-rest_len;
}

void Querycache_stream::store_ll(ulonglong ll)
{
#ifndef NDEBUG
  stored_size+= 8;
#endif
  size_t rest_len= data_end - cur_data;
  if (rest_len > 7)
  {
    int8store(cur_data, ll);
    cur_data+= 8;
    return;
  }
  if (!rest_len)
  {
    use_next_block(TRUE);
    int8store(cur_data, ll);
    cur_data+= 8;
    return;
  }
  memcpy(cur_data, &ll, rest_len);
  use_next_block(TRUE);
  memcpy(cur_data, ((uchar*)&ll)+rest_len, 8-rest_len);
  cur_data+= 8-rest_len;
}

void Querycache_stream::store_str_only(const char *str, size_t str_len)
{
#ifndef NDEBUG
  stored_size+= str_len;
#endif
  do
  {
    size_t rest_len= data_end - cur_data;
    if (rest_len >= str_len)
    {
      memcpy(cur_data, str, str_len);
      cur_data+= str_len;
      return;
    }
    memcpy(cur_data, str, rest_len);
    use_next_block(TRUE);
    str_len-= rest_len;
    str+= rest_len;
  } while(str_len);
}

void Querycache_stream::store_str(const char *str, size_t str_len)
{
  store_int(static_cast<uint>(str_len));
  store_str_only(str, str_len);
}

void Querycache_stream::store_safe_str(const char *str, size_t str_len)
{
  if (str)
  {
    store_int(static_cast<uint>(str_len+1));
    store_str_only(str, str_len);
  }
  else
    store_int(0);
}

uchar Querycache_stream::load_uchar()
{
  if (cur_data == data_end)
    use_next_block(FALSE);
  return *(cur_data++);
}

ushort Querycache_stream::load_short()
{
  ushort result;
  if (data_end-cur_data > 1)
  {
    result= uint2korr(cur_data);
    cur_data+= 2;
    return result;
  }
  if (data_end == cur_data)
  {
    use_next_block(FALSE);
    result= uint2korr(cur_data);
    cur_data+= 2;
    return result;
  }
  ((uchar*)&result)[0]= *cur_data;
  use_next_block(FALSE);
  ((uchar*)&result)[1]= *(cur_data++);
  return result;
}

uint Querycache_stream::load_int()
{
  int result;
  size_t rest_len= data_end - cur_data;
  if (rest_len > 3)
  {
    result= uint4korr(cur_data);
    cur_data+= 4;
    return result;
  }
  if (!rest_len)
  {
    use_next_block(FALSE);
    result= uint4korr(cur_data);
    cur_data+= 4;
    return result;
  }
  char buf[4], *buf_p= buf;
  memcpy(buf, cur_data, rest_len);
  use_next_block(FALSE);
  memcpy(buf+rest_len, cur_data, 4-rest_len);
  cur_data+= 4-rest_len;
  result= uint4korr(buf_p);
  return result;
}

ulonglong Querycache_stream::load_ll()
{
  ulonglong result;
  size_t rest_len= data_end - cur_data;
  if (rest_len > 7)
  {
    result= uint8korr(cur_data);
    cur_data+= 8;
    return result;
  }
  if (!rest_len)
  {
    use_next_block(FALSE);
    result= uint8korr(cur_data);
    cur_data+= 8;
    return result;
  }
  memcpy(&result, cur_data, rest_len);
  use_next_block(FALSE);
  memcpy(((uchar*)&result)+rest_len, cur_data, 8-rest_len);
  cur_data+= 8-rest_len;
  return result;
}

void Querycache_stream::load_str_only(char *buffer, size_t str_len)
{
  do
  {
    size_t rest_len= data_end - cur_data;
    if (rest_len >= str_len)
    {
      memcpy(buffer, cur_data, str_len);
      cur_data+= str_len;
      buffer+= str_len;
      break;
    }
    memcpy(buffer, cur_data, rest_len);
    use_next_block(FALSE);
    str_len-= rest_len;
    buffer+= rest_len;
  } while(str_len);
  *buffer= 0;
}

char *Querycache_stream::load_str(MEM_ROOT *alloc, uint *str_len)
{
  char *result;
  *str_len= load_int();
  if (!(result= (char*) alloc_root(alloc, *str_len + 1)))
    return 0;
  load_str_only(result, *str_len);
  return result;
}

int Querycache_stream::load_safe_str(MEM_ROOT *alloc, char **str, uint *str_len)
{
  if (!(*str_len= load_int()))
  {
    *str= NULL;
    return 0;
  }
  (*str_len)--;
  if (!(*str= (char*) alloc_root(alloc, *str_len + 1)))
    return 1;
  load_str_only(*str, *str_len);
  return 0;
}

int Querycache_stream::load_column(MEM_ROOT *alloc, char** column)
{
  int len;
  if (!(len = load_int()))
  {
    *column= NULL;
    return 0;
  }
  len--;
  if (!(*column= (char *)alloc_root(alloc, len + sizeof(uint) + 1)))
    return 1;
  *((uint*)*column)= len;
  (*column)+= sizeof(uint);
  load_str_only(*column, len);
  return 1;
}

uint emb_count_querycache_size(THD *thd)
{
  uint result= 0;
  MYSQL_FIELD *field;
  MYSQL_FIELD *field_end;
  MYSQL_ROWS *cur_row;
  my_ulonglong n_rows;
  MYSQL_DATA *data= thd->first_data;

  while (data->embedded_info->next)
    data= data->embedded_info->next;
  field= data->embedded_info->fields_list;
  field_end= field + data->fields;
  
  if (!field)
    return result;
  *data->embedded_info->prev_ptr= NULL; // this marks the last record
  cur_row= data->data;
  n_rows= data->rows;
  /* n_fields + n_rows + field_info * n_fields */
  result+= (uint) (4+8 + 42*data->fields);

  for(; field < field_end; field++)
  {
    result+= field->name_length + field->table_length +
      field->org_name_length + field->org_table_length + field->db_length +
      field->catalog_length;
    if (field->def)
      result+= field->def_length;
  }
  
  if (thd->get_protocol()->type() == Protocol::PROTOCOL_BINARY)
  {
    result+= (uint) (4*n_rows);
    for (; cur_row; cur_row=cur_row->next)
      result+= cur_row->length;
  }
  else
  {
    result+= (uint) (4*n_rows*data->fields);
    for (; cur_row; cur_row=cur_row->next)
    {
      MYSQL_ROW col= cur_row->data;
      MYSQL_ROW col_end= col + data->fields;
      for (; col < col_end; col++)
        if (*col)
          result+= *(uint *)((*col) - sizeof(uint));
    }
  }
  return result;
}

void emb_store_querycache_result(Querycache_stream *dst, THD *thd)
{
  MYSQL_FIELD *field;
  MYSQL_FIELD *field_end;
  MYSQL_ROWS *cur_row;
  my_ulonglong n_rows;
  MYSQL_DATA *data= thd->first_data;

  DBUG_ENTER("emb_store_querycache_result");

  while (data->embedded_info->next)
    data= data->embedded_info->next;
  field= data->embedded_info->fields_list;
  field_end= field + data->fields;

  if (!field)
    DBUG_VOID_RETURN;

  *data->embedded_info->prev_ptr= NULL; // this marks the last record
  cur_row= data->data;
  n_rows= data->rows;

  dst->store_int((uint)data->fields);
  dst->store_ll((ulonglong)n_rows);

  for(; field < field_end; field++)
  {
    dst->store_int((uint)field->length);
    dst->store_int((uint)field->max_length);
    dst->store_uchar((uchar)field->type);
    dst->store_short((ushort)field->flags);
    dst->store_short((ushort)field->charsetnr);
    dst->store_uchar((uchar)field->decimals);
    dst->store_str(field->name, field->name_length);
    dst->store_str(field->table, field->table_length);
    dst->store_str(field->org_name, field->org_name_length);
    dst->store_str(field->org_table, field->org_table_length);
    dst->store_str(field->db, field->db_length);
    dst->store_str(field->catalog, field->catalog_length);
    dst->store_safe_str(field->def, field->def_length);
  }

  if (thd->get_protocol()->type() == Protocol::PROTOCOL_BINARY)
  {
    for (; cur_row; cur_row=cur_row->next)
      dst->store_str((char *) cur_row->data, cur_row->length);
  }
  else
  {
    for (; cur_row; cur_row=cur_row->next)
    {
      MYSQL_ROW col= cur_row->data;
      MYSQL_ROW col_end= col + data->fields;
      for (; col < col_end; col++)
      {
        uint len= *col ? *(uint *)((*col) - sizeof(uint)) : 0;
        dst->store_safe_str(*col, len);
      }
    }
  }
  assert(emb_count_querycache_size(thd) == dst->stored_size);
  DBUG_VOID_RETURN;
}

int emb_load_querycache_result(THD *thd, Querycache_stream *src)
{
  MYSQL_DATA *data= thd->alloc_new_dataset();
  MYSQL_FIELD *field;
  MYSQL_FIELD *field_end;
  MEM_ROOT *f_alloc;
  MYSQL_ROWS *row, *end_row;
  MYSQL_ROWS **prev_row;
  ulonglong rows;
  MYSQL_ROW columns;
  DBUG_ENTER("emb_load_querycache_result");

  if (!data)
    goto err;
  init_alloc_root(PSI_NOT_INSTRUMENTED, &data->alloc, 8192, 0);
  f_alloc= &data->alloc;

  data->fields= src->load_int();
  rows= src->load_ll();

  if (!(field= (MYSQL_FIELD *)
        alloc_root(f_alloc,data->fields*sizeof(MYSQL_FIELD))))
    goto err;
  data->embedded_info->fields_list= field;
  for(field_end= field+data->fields; field < field_end; field++)
  {
    field->length= src->load_int();
    field->max_length= (unsigned int)src->load_int();
    field->type= (enum enum_field_types)src->load_uchar();
    field->flags= (unsigned int)src->load_short();
    field->charsetnr= (unsigned int)src->load_short();
    field->decimals= src->load_uchar();

    if (!(field->name= src->load_str(f_alloc, &field->name_length))          ||
        !(field->table= src->load_str(f_alloc,&field->table_length))         ||
        !(field->org_name= src->load_str(f_alloc, &field->org_name_length))  ||
        !(field->org_table= src->load_str(f_alloc, &field->org_table_length))||
        !(field->db= src->load_str(f_alloc, &field->db_length))              ||
        !(field->catalog= src->load_str(f_alloc, &field->catalog_length))    ||
        src->load_safe_str(f_alloc, &field->def, &field->def_length))
      goto err;
  }
  
  data->rows= rows;
  if (!rows)
    goto return_ok;

  if (thd->get_protocol()->type() == Protocol::PROTOCOL_BINARY)
  {
    uint length;
    row= (MYSQL_ROWS *)alloc_root(&data->alloc,
                                  (size_t) (rows * sizeof(MYSQL_ROWS)));
    end_row= row + rows;
    data->data= row;

    for (prev_row= &row->next; row < end_row; prev_row= &row->next, row++)
    {
      *prev_row= row;
      row->data= (MYSQL_ROW) src->load_str(&data->alloc, &length);
      row->length= length;
    }
  }
  else
  {
    row= (MYSQL_ROWS *)alloc_root(&data->alloc,
        (uint) (rows * sizeof(MYSQL_ROWS) +
          rows*(data->fields+1)*sizeof(char*)));
    end_row= row + rows;
    columns= (MYSQL_ROW)end_row;

    data->data= row;

    for (prev_row= &row->next; row < end_row; prev_row= &row->next, row++)
    {
      *prev_row= row;
      row->data= columns;
      MYSQL_ROW col_end= columns + data->fields;
      for (; columns < col_end; columns++)
        src->load_column(&data->alloc, columns);

      *(columns++)= NULL;
    }
  }
  *prev_row= NULL;
  data->embedded_info->prev_ptr= prev_row;
return_ok:
  net_send_eof(thd, thd->server_status,
               thd->get_stmt_da()->current_statement_cond_count());
  DBUG_RETURN(0);
err:
  DBUG_RETURN(1);
}

