components/mysql_server/my_metadata.cc

/* Copyright (c) 2016, 2017, 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 as published by
the Free Software Foundation; version 2 of the License.

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 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 "components/mysql_server/my_metadata.h"

my_metadata::my_metadata()
{}

my_metadata::my_metadata(my_metadata &other)
  : data(other.data)
{}

my_metadata::const_iterator::const_iterator(
  my_unordered_string_to_string_map::const_iterator iter,
  my_unordered_string_to_string_map *data_arg)
  : my_unordered_string_to_string_map::const_iterator(iter), data(data_arg)
{}

/**
  Gets pointer to structure the iterator is iterating over.
*/
my_unordered_string_to_string_map*
  my_metadata::const_iterator::get_data()
{
  return data;
}

/**
  Checks if iterator is pointing behind the end element.
*/
bool my_metadata::const_iterator::is_at_end()
{
  return (*static_cast<my_unordered_string_to_string_map::const_iterator *>(
      this)) ==
    data->cend();
}

/**
  Sets a value for the name specified.
  Adds to the metadata list if absent. Copies the data into the structure,
  original values don't need to be around after this function is called.

  @param name The name string of the metadata pair to be added.
  @param value The value string of the metadata pair.
  @return Status of performed operation
  @retval false success
  @retval true failure
*/
bool my_metadata::set_value(const char* name, const char* value)
{
  try
  {
    my_string key_str= name;
    my_string value_str= value;

    my_unordered_string_to_string_map::iterator it= data.find(key_str);
    if (it != data.end())
    {
      it->second= value_str;
    }
    else
    {
      data.emplace(std::move(key_str), std::move(value_str));
    }
    return false;
  }
  catch (...)
  {
  }
  return true;
}

/**
  Gets value for the name specified.
  The value is unmodified if not found.
  Doesn't copy the result value, so it requires synchronization to prevent other
  threads to modify structure.

  @param name The name string of the metadata pair.
  @param [out] value The value string of the metadata pair.
  @return Status of performed operation
  @retval false success
  @retval true failure
*/
bool my_metadata::get_value(const char* name, const char** value)
{
  try
  {
    my_unordered_string_to_string_map::const_iterator iter= data.find(
      my_string(name));
    if (iter == data.end())
    {
      return true;
    }
    *value= iter->second.c_str();
    return false;
  }
  catch (...)
  {
  }
  return true;
}

/**
  Creates an iterator over the metadata.

  Positions on the first value.

  @return Reference to the iterator created.
*/
my_metadata::const_iterator my_metadata::create_iterator()
{
  return my_metadata::const_iterator(data.begin(), &data);
}

/**
  Frees an iterator over the metadata.
  Iterator must be allocated through create_iterator();

  @param iter Pointer to the iterator to release.
  @return Status of performed operation
  @retval false success
  @retval true failure
*/
bool my_metadata::release_iterator(const_iterator* iter)
{
  try
  {
    delete iter;
    return false;
  }
  catch (...)
  {
  }
  return true;
}