Drizzled Public API Documentation

cache.h
00001 /* - mode: c; c-basic-offset: 2; indent-tabs-mode: nil; -*-
00002  *  vim:expandtab:shiftwidth=2:tabstop=2:smarttab:
00003  *
00004  *  Copyright (C) 2010 Brian Aker
00005  *
00006  *  This program is free software; you can redistribute it and/or modify
00007  *  it under the terms of the GNU General Public License as published by
00008  *  the Free Software Foundation; either version 2 of the License, or
00009  *  (at your option) any later version.
00010  *
00011  *  This program is distributed in the hope that it will be useful,
00012  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
00013  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
00014  *  GNU General Public License for more details.
00015  *
00016  *  You should have received a copy of the GNU General Public License
00017  *  along with this program; if not, write to the Free Software
00018  *  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
00019  */
00020 
00021 #pragma once
00022 
00023 #include <boost/bind.hpp>
00024 
00025 #include <drizzled/error.h>
00026 #include <drizzled/catalog.h>
00027 #include <drizzled/plugin/catalog.h>
00028 
00029 #include <boost/unordered_map.hpp>
00030 #include <boost/thread/mutex.hpp>
00031 
00032 namespace drizzled {
00033 
00034 namespace plugin {
00035 class Catalog;
00036 }
00037 namespace generator {
00038 namespace catalog {
00039 class Cache;
00040 class Instance;
00041 
00042 } //namespace catalog
00043 } //namespace generator
00044 
00045 namespace catalog {
00046 
00047 namespace lock {
00048 class Create;
00049 class Erase;
00050 
00051 } //namespace lock
00052 
00053 class Cache
00054 {
00055   static inline Cache &singleton()
00056   {
00057     static Cache open_cache;
00058 
00059     return open_cache;
00060   }
00061 
00062   size_t size() const
00063   {
00064     return cache.size();
00065   }
00066 
00067   void rehash(size_t arg)
00068   {
00069     cache.rehash(arg);
00070   }
00071 
00072   Instance::shared_ptr find(const identifier::Catalog &identifier, drizzled::error_t &error);
00073   bool exist(const identifier::Catalog &identifier);
00074   bool erase(const identifier::Catalog &identifier, drizzled::error_t &error);
00075   bool insert(const identifier::Catalog &identifier, Instance::shared_ptr instance, drizzled::error_t &error);
00076   bool lock(const identifier::Catalog &identifier, drizzled::error_t &error);
00077   bool unlock(const identifier::Catalog &identifier, drizzled::error_t &error);
00078 
00079   friend class drizzled::generator::catalog::Cache;
00080   friend class drizzled::plugin::Catalog;
00081   friend class drizzled::catalog::lock::Erase;
00082   friend class drizzled::catalog::lock::Create;
00083 
00084   void copy(catalog::Instance::vector &vector);
00085 
00086   typedef boost::unordered_map< identifier::Catalog, catalog::Instance::shared_ptr> unordered_map;
00087 
00088   unordered_map cache;
00089   boost::mutex _mutex;
00090 };
00091 
00092 
00093 namespace lock {
00094 
00095 class Erase
00096 {
00097   bool _locked;
00098   const identifier::Catalog &identifier;
00099   drizzled::error_t error;
00100 
00101 public:
00102   Erase(const identifier::Catalog &identifier_arg) :
00103     _locked(false),
00104     identifier(identifier_arg)
00105   {
00106     init();
00107   }
00108 
00109   bool locked () const
00110   {
00111     return _locked;
00112   }
00113 
00114   ~Erase()
00115   {
00116     if (_locked)
00117     {
00118       if (not catalog::Cache::singleton().unlock(identifier, error))
00119       {
00120         my_error(error, identifier);
00121         assert(0);
00122       }
00123     }
00124   }
00125 
00126 private:
00127   void init()
00128   {
00129     // We insert a lock into the cache, if this fails we bail.
00130     if (not catalog::Cache::singleton().lock(identifier, error))
00131     {
00132       assert(0);
00133       return;
00134     }
00135 
00136     _locked= true;
00137   }
00138 };
00139 
00140 
00141 class Create
00142 {
00143   bool _locked;
00144   const identifier::Catalog &identifier;
00145   drizzled::error_t error;
00146 
00147 public:
00148   Create(const identifier::Catalog &identifier_arg) :
00149     _locked(false),
00150     identifier(identifier_arg)
00151   {
00152     init();
00153   }
00154 
00155   bool locked () const
00156   {
00157     return _locked;
00158   }
00159 
00160   ~Create()
00161   {
00162     if (_locked)
00163     {
00164       if (not catalog::Cache::singleton().unlock(identifier, error))
00165       {
00166         my_error(error, identifier);
00167         assert(0);
00168       }
00169     }
00170   }
00171 
00172 
00173 private:
00174   void init()
00175   {
00176     // We insert a lock into the cache, if this fails we bail.
00177     if (not catalog::Cache::singleton().lock(identifier, error))
00178     {
00179       my_error(error, identifier);
00180       return;
00181     }
00182 
00183     _locked= true;
00184   }
00185 };
00186 
00187 } /* namespace lock */
00188 } /* namespace catalog */
00189 } /* namespace drizzled */
00190