release/src/router/mysql/storage/ndb/src/common/transporter/SHM_Transporter.hpp

   1 /* Copyright (c) 2003-2005 MySQL AB
   2
   3    This program is free software; you can redistribute it and/or modify
   4    it under the terms of the GNU General Public License as published by
   5    the Free Software Foundation; version 2 of the License.
   6
   7    This program is distributed in the hope that it will be useful,
   8    but WITHOUT ANY WARRANTY; without even the implied warranty of
   9    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  10    GNU General Public License for more details.
  11
  12    You should have received a copy of the GNU General Public License
  13    along with this program; if not, write to the Free Software
  14    Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA */
  15
  16 #ifndef SHM_Transporter_H
  17 #define SHM_Transporter_H
  18
  19 #include "Transporter.hpp"
  20 #include "SHM_Buffer.hpp"
  21
  22 #ifdef NDB_WIN32
  23 typedef Uint32 key_t;
  24 #endif
  25
  26 /**
  27  * class SHMTransporter
  28  * @brief - main class for the SHM transporter.
  29  */
  30
  31 class SHM_Transporter : public Transporter {
  32   friend class TransporterRegistry;
  33 public:
  34   SHM_Transporter(TransporterRegistry &,
  35                   const char *lHostName,
  36                   const char *rHostName,
  37                   int r_port,
  38                   bool isMgmConnection,
  39                   NodeId lNodeId,
  40                   NodeId rNodeId,
  41                   NodeId serverNodeId,
  42                   bool checksum,
  43                   bool signalId,
  44                   key_t shmKey,
  45                   Uint32 shmSize);
  46
  47   /**
  48    * SHM destructor
  49    */
  50   virtual ~SHM_Transporter();
  51
  52   /**
  53    * Do initialization
  54    */
  55   bool initTransporter();
  56
  57   Uint32 * getWritePtr(Uint32 lenBytes, Uint32 prio)
  58   {
  59     return (Uint32 *)writer->getWritePtr(lenBytes);
  60   }
  61
  62   void updateWritePtr(Uint32 lenBytes, Uint32 prio)
  63   {
  64     writer->updateWritePtr(lenBytes);
  65     m_last_signal += lenBytes;
  66     if(m_last_signal >= m_signal_threshold)
  67     {
  68       doSend();
  69     }
  70   }
  71
  72   void getReceivePtr(Uint32 ** ptr, Uint32 ** eod){
  73     reader->getReadPtr(* ptr, * eod);
  74   }
  75
  76   void updateReceivePtr(Uint32 * ptr){
  77     reader->updateReadPtr(ptr);
  78   }
  79
  80 protected:
  81   /**
  82    * disconnect a segmnet
  83    * -# deletes the shm buffer associated with a segment
  84    * -# marks the segment for removal
  85    */
  86   void disconnectImpl();
  87
  88   /**
  89    * Blocking
  90    *
  91    * -# Create shm segment
  92    * -# Attach to it
  93    * -# Wait for someone to attach (max wait = timeout), then rerun again
  94    *    until connection established.
  95    * @param timeOutMillis - the time to sleep before (ms) trying again.
  96    * @returns - True if the server managed to hook up with the client,
  97    *            i.e., both agrees that the other one has setup the segment.
  98    *            Otherwise false.
  99    */
 100   virtual bool connect_server_impl(NDB_SOCKET_TYPE sockfd);
 101
 102   /**
 103    * Blocking
 104    *
 105    * -# Attach to shm segment
 106    * -# Check if the segment is setup
 107    * -# Check if the server set it up
 108    * -# If all clear, return.
 109    * @param timeOutMillis - the time to sleep before (ms) trying again.
 110    * @returns - True if the client managed to hook up with the server,
 111    *            i.e., both agrees that the other one has setup the segment.
 112    *            Otherwise false.
 113    */
 114   virtual bool connect_client_impl(NDB_SOCKET_TYPE sockfd);
 115
 116   bool connect_common(NDB_SOCKET_TYPE sockfd);
 117
 118   bool ndb_shm_create();
 119   bool ndb_shm_get();
 120   bool ndb_shm_attach();
 121
 122   /**
 123    * Check if there are two processes attached to the segment (a connection)
 124    * @return - True if the above holds. Otherwise false.
 125    */
 126   bool checkConnected();
 127
 128
 129   /**
 130    * Initialises the SHM_Reader and SHM_Writer on the segment
 131    */
 132   void setupBuffers();
 133
 134   /**
 135    * doSend (i.e signal receiver)
 136    */
 137   void doSend();
 138   int m_remote_pid;
 139   Uint32 m_last_signal;
 140   Uint32 m_signal_threshold;
 141
 142   virtual Uint32 get_free_buffer() const;
 143
 144 private:
 145   bool _shmSegCreated;
 146   bool _attached;
 147   bool m_connected;
 148
 149   key_t shmKey;
 150   volatile Uint32 * serverStatusFlag;
 151   volatile Uint32 * clientStatusFlag;
 152   bool setupBuffersDone;
 153
 154 #ifdef NDB_WIN32
 155   HANDLE hFileMapping;
 156 #else
 157   int shmId;
 158 #endif
 159
 160   int shmSize;
 161   char * shmBuf;
 162
 163   SHM_Reader * reader;
 164   SHM_Writer * writer;
 165
 166   /**
 167    * @return - True if the reader has data to read on its segment.
 168    */
 169   bool hasDataToRead() const {
 170     return reader->empty() == false;
 171   }
 172
 173   void make_error_info(char info[], int sz);
 174 };
 175
 176 #endif