opt_trace_context.h

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/* Copyright (c) 2011, 2012, 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  */

#ifndef OPT_TRACE_CONTEXT_INCLUDED
#define OPT_TRACE_CONTEXT_INCLUDED

#include "my_config.h"  // OPTIMIZER_TRACE
#include "sql_array.h"  // Dynamic_array

#ifdef OPTIMIZER_TRACE

class Opt_trace_stmt;           // implementation detail local to opt_trace.cc


class Opt_trace_context
{
public:

  Opt_trace_context() : pimpl(NULL), I_S_disabled(0) {}
  ~Opt_trace_context();

  bool start(bool support_I_S,
             bool support_dbug_or_missing_priv,
             bool end_marker, bool one_line,
             long offset, long limit, ulong max_mem_size,
             ulonglong features);

  void end();

  bool is_started() const
  { return unlikely(pimpl != NULL) && pimpl->current_stmt_in_gen != NULL; }

  bool support_I_S() const;

  void set_query(const char* query, size_t length,
                 const CHARSET_INFO *charset);

  void reset();

  bool get_end_marker() const { return pimpl->end_marker; }
  bool get_one_line() const { return pimpl->one_line; }

  static const char *flag_names[];

  enum {
    FLAG_DEFAULT=    0,
    FLAG_ENABLED=    1 << 0,
    FLAG_ONE_LINE=   1 << 1
  };

  static const char *feature_names[];

  enum feature_value {
    GREEDY_SEARCH=      1 << 0,
    RANGE_OPTIMIZER=    1 << 1,
    DYNAMIC_RANGE=      1 << 2,
    REPEATED_SUBSELECT= 1 << 3,
    /*
      If you add here, update feature_value of empty implementation
      and default_features!
    */
    MISC=               1 << 7
  };

  void missing_privilege();

  static const feature_value default_features;

  bool feature_enabled (feature_value f) const
  { return unlikely(pimpl != NULL) && (pimpl->features & f); }

  Opt_trace_stmt *get_current_stmt_in_gen()
  { return pimpl->current_stmt_in_gen; }

  const Opt_trace_stmt *get_next_stmt_for_I_S(long *got_so_far) const;

  void disable_I_S_for_this_and_children()
  {
    ++I_S_disabled;
    if (unlikely(pimpl != NULL))
      pimpl->disable_I_S_for_this_and_children();
  }

  void restore_I_S()
  {
    --I_S_disabled;
    DBUG_ASSERT(I_S_disabled >= 0);
    if (unlikely(pimpl != NULL))
      pimpl->restore_I_S();
  }

private:

  class Opt_trace_context_impl
  {
  public:
    Opt_trace_context_impl() : current_stmt_in_gen(NULL),
      features(feature_value(0)), offset(0), limit(0), since_offset_0(0)
    {}

    void disable_I_S_for_this_and_children();
    void restore_I_S();

    Opt_trace_stmt *current_stmt_in_gen;

    Dynamic_array<Opt_trace_stmt *> stack_of_current_stmts;

    Dynamic_array<Opt_trace_stmt *> all_stmts_for_I_S;
    Dynamic_array<Opt_trace_stmt *> all_stmts_to_del;

    bool end_marker;        
    bool one_line;
    feature_value features;
    long offset;
    long limit;
    size_t max_mem_size;

    long since_offset_0;
  };

  Opt_trace_context_impl *pimpl;     

  int I_S_disabled;

  void purge_stmts(bool purge_all);

  size_t allowed_mem_size_for_current_stmt() const;

  Opt_trace_context(const Opt_trace_context&);
  Opt_trace_context& operator=(const Opt_trace_context&);
};

#else /* OPTIMIZER_TRACE */

class Opt_trace_context
{
public:
  enum feature_value {
    GREEDY_SEARCH=      1 << 0,
    RANGE_OPTIMIZER=    1 << 1,
    DYNAMIC_RANGE=      1 << 2,
    REPEATED_SUBSELECT= 1 << 3,
    MISC=               1 << 7
  };
  enum {
    FLAG_DEFAULT=    0,
    FLAG_ENABLED=    1 << 0,
    FLAG_ONE_LINE=   1 << 1
  };
  static bool is_started() { return false; }
};

#endif /* OPTIMIZER_TRACE */

#endif /* OPT_TRACE_CONTEXT_INCLUDED */