mariadb/sql/opt_trace_context.h

#ifndef OPT_TRACE_CONTEXT_INCLUDED
#define OPT_TRACE_CONTEXT_INCLUDED

#include "sql_array.h"

class Opt_trace_stmt;

class Opt_trace_context
{
public:
   Opt_trace_context();
  ~Opt_trace_context();

  void start(THD *thd, TABLE_LIST *tbl,
             enum enum_sql_command sql_command,
             const char *query,
             size_t query_length,
             const CHARSET_INFO *query_charset,
             ulong max_mem_size_arg);
  void end();
  void set_query(const char *query, size_t length, const CHARSET_INFO *charset);
  void delete_traces();
  void set_allowed_mem_size(size_t mem_size);
  size_t remaining_mem_size();

private:
  Opt_trace_stmt* top_trace()
  {
    return *(traces.front());
  }

public:

  /*
    This returns the top trace from the list of traces. This function
    is used when we want to see the contents of the INFORMATION_SCHEMA.OPTIMIZER_TRACE
  table.
  */

  Opt_trace_stmt* get_top_trace()
  {
    if (!traces.elements())
      return NULL;
    return top_trace();
  }

  /*
    This returns the current trace, to which we are still writing and has not been finished
  */

  Json_writer* get_current_json();

  bool empty()
  {
    return static_cast<uint>(traces.elements()) == 0;
  }

  bool is_started()
  {
    return current_trace && is_enabled();
  }

  bool disable_tracing_if_required();

  bool enable_tracing_if_required();

  bool is_enabled();

  void missing_privilege();

  static const char *flag_names[];
  enum
  {
    FLAG_DEFAULT = 0,
    FLAG_ENABLED = 1 << 0
  };

private:
  /*
    List of traces (currently it stores only 1 trace)
  */
  Dynamic_array<Opt_trace_stmt*> traces;
  Opt_trace_stmt *current_trace;
  size_t max_mem_size;
};

#endif /* OPT_TRACE_CONTEXT_INCLUDED */