safecounter.hpp

mysql-5.0.22.tar.gz源码包

/* Copyright (C) 2003 MySQL AB

   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; either version 2 of the License, or
   (at your option) any later version.

   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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA */

#ifndef __SAFE_COUNTER_HPP
#define __SAFE_COUNTER_HPP

/*************************************************************
 *
 * SafeCounter "automates" three way to node-fais safe protocols
 * for "slave" failures.  This is done by registing "fake" signals
 * to be sent in case of nodefailure.
 *
 * init<SignalClass>(..., GSN, senderData);
 *
 * It is implemented so that one can replace SignalCounter with
 * SafeCounter (SignalCounter should probably go away with time)
 * methods:
 * clearWaitingFor(nodeId);
 * done();
 * etc.
 *
 * If included in a new block method
 * SafeCounterManager::execNODE_FAILREP must included in
 * <block>::execNODE_FAILREP
 *
 * the SignalClass must have senderRef, senderData and errorCode
 * and also ErrorCode::NF_FakeErrorREF, implemented
 *
 * SafeCounter consists of 3 parts:
 * SafeCounterManager which keeps track of active "counters"
 * SafeCounterHandle to store "i-value" in your "op record"
 * SafeCounter as a temporary variable only to use on the stack
 * for operation
 *
 */

#include <NodeBitmask.hpp>
#include "DLList.hpp"
#include "VMSignal.hpp"

class SimulatedBlock;

/**
 *
 */
class SafeCounterManager {
  friend class SafeCounter;
  friend class SafeCounterHandle;
  friend class SimulatedBlock;
public:
  SafeCounterManager(class SimulatedBlock &);
  
  bool setSize(Uint32 maxNoOfActiveMutexes, bool exit_on_error = true);
  Uint32 getSize() const ;

  void execNODE_FAILREP(Signal*); 
  void printNODE_FAILREP(); 

private:
  struct ActiveCounter { /** sizeof = 7words = 28bytes */ 
  public:
    Uint32 m_senderData;
    NodeBitmask m_nodes;
    struct SignalDesc {
    public:
      Uint16 m_gsn; 
      Uint16 m_block;
      Uint8 m_senderRefOffset;
      Uint8 m_senderDataOffset;
      Uint8 m_errorCodeOffset;
      Uint8 m_nodeFailErrorCode;
    } m_signalDesc;
    union {
      Uint32 nextPool;
      Uint32 nextList;
    };
    Uint32 prevList;
  };

  typedef Ptr<ActiveCounter> ActiveCounterPtr;
  
  bool seize(ActiveCounterPtr& ptr);
  void release(ActiveCounterPtr& ptr);
  void getPtr(ActiveCounterPtr& ptr, Uint32 ptrI);

  SimulatedBlock & m_block;
  ArrayPool<ActiveCounter> m_counterPool;
  DLList<ActiveCounter> m_activeCounters;

  BlockReference reference() const;
  void progError(int line, int err_code, const char* extra = 0);
};


class SafeCounterHandle {
  friend class SafeCounter;
public:
  SafeCounterHandle();

  /**
   * Return if done (no nodes set in bitmask)
   */
  bool clearWaitingFor(SafeCounterManager& mgr, Uint32 nodeId);
  
  bool done() const;
  
private:
  Uint32 m_activeCounterPtrI;
};

class SafeCounter {
  friend class SafeCounterManager;
public:
  SafeCounter(SafeCounterManager&, SafeCounterHandle&);
  
  template<typename SignalClass>
    bool init(Uint16 block, Uint16 GSN, Uint32 senderData);
  
  template<typename SignalClass>
    bool init(NodeReceiverGroup rg, Uint16 GSN, Uint32 senderData);

  template<typename SignalClass>
    bool init(NodeReceiverGroup rg, Uint32 senderData);
  
  ~SafeCounter();
  
  void clearWaitingFor();
  
  /**
   * When sending to different node
   */
  void setWaitingFor(Uint32 nodeId);
  bool clearWaitingFor(Uint32 nodeId);
  bool forceClearWaitingFor(Uint32 nodeId);
  
  bool isWaitingFor(Uint32 nodeId) const;
  bool done() const;

  const char * getText() const; /* ? needed for, some portability issues */

  SafeCounter& operator=(const NdbNodeBitmask&);
  SafeCounter& operator=(const NodeReceiverGroup&);
private:
  Uint32 m_count;
  NodeBitmask m_nodes;
  
  SafeCounterManager & m_mgr;
  SafeCounterManager::ActiveCounterPtr m_ptr;
  
  Uint32 & m_activeCounterPtrI;
};

inline
SafeCounterHandle::SafeCounterHandle(){
  m_activeCounterPtrI = RNIL;
}

inline
bool
SafeCounterHandle::done() const {
  return m_activeCounterPtrI == RNIL;
}

inline
SafeCounter::SafeCounter(SafeCounterManager& mgr, SafeCounterHandle& handle)
  : m_mgr(mgr),
    m_activeCounterPtrI(handle.m_activeCounterPtrI)
{
  m_ptr.i = handle.m_activeCounterPtrI;
  if (m_ptr.i == RNIL) {
    m_nodes.clear();
    m_count = 0;
  } else {
    m_mgr.getPtr(m_ptr, m_ptr.i);
    m_nodes = m_ptr.p->m_nodes;
    m_count = m_nodes.count();
  }
}

template<typename Ref>
inline
bool
SafeCounter::init(Uint16 block, Uint16 GSN, Uint32 senderData){
  
  SafeCounterManager::ActiveCounter::SignalDesc signalDesc;
  signalDesc.m_gsn = GSN;
  signalDesc.m_block = block;
  signalDesc.m_errorCodeOffset = offsetof(Ref, errorCode) >> 2;
  signalDesc.m_senderRefOffset = offsetof(Ref, senderRef) >> 2;
  signalDesc.m_senderDataOffset = offsetof(Ref, senderData) >> 2;
  signalDesc.m_nodeFailErrorCode = Ref::NF_FakeErrorREF;
  assert(((Uint32)Ref::NF_FakeErrorREF) < 256);
  
  if(m_ptr.i == RNIL){
    SafeCounterManager::ActiveCounterPtr ptr;
    if(m_mgr.seize(ptr)){
      ptr.p->m_senderData = senderData;
      ptr.p->m_signalDesc = signalDesc;
      m_ptr = ptr;
      return true;
    }
    return false;
  }

  if(m_count == 0){
    m_ptr.p->m_senderData = senderData;
    m_ptr.p->m_signalDesc = signalDesc;
    return true;
  } 

  ErrorReporter::handleAssert("SafeCounter::init twice", __FILE__, __LINE__);  
  return false;
}

template<typename Ref>
inline
bool
SafeCounter::init(NodeReceiverGroup rg, Uint16 GSN, Uint32 senderData){
  
  bool b = init<Ref>(rg.m_block, GSN, senderData);
  m_nodes = rg.m_nodes;
  m_count = m_nodes.count();
  return b;
}

template<typename Ref>
inline
bool
SafeCounter::init(NodeReceiverGroup rg, Uint32 senderData){
  
  bool b = init<Ref>(rg.m_block, Ref::GSN, senderData);
  m_nodes = rg.m_nodes;
  m_count = m_nodes.count();
  return b;
}

inline
void 
SafeCounter::setWaitingFor(Uint32 nodeId) {
  if(!m_nodes.get(nodeId)){
    m_nodes.set(nodeId);
    m_count++;
    return;
  }
  ErrorReporter::handleAssert("SafeCounter::set", __FILE__, __LINE__);
}

inline
bool
SafeCounter::isWaitingFor(Uint32 nodeId) const {
  return m_nodes.get(nodeId);
}

inline
bool
SafeCounter::done() const {
  return m_count == 0;
}

inline
bool
SafeCounter::clearWaitingFor(Uint32 nodeId) {
  if(m_count > 0 && m_nodes.get(nodeId)){
    m_count--;
    m_nodes.clear(nodeId);
    return (m_count == 0);
  }
  ErrorReporter::handleAssert("SafeCounter::clear", __FILE__, __LINE__);
  return false;
}

inline
void
SafeCounter::clearWaitingFor(){
  m_count = 0;
  m_nodes.clear();
}

inline
bool
SafeCounter::forceClearWaitingFor(Uint32 nodeId){
  if(isWaitingFor(nodeId)){
    return clearWaitingFor(nodeId);
  }
  return (m_count == 0);
}

#endif