1 files changed, 170 insertions, 0 deletions
diff --git a/cpp/src/Freeze/SharedDb.cpp b/cpp/src/Freeze/SharedDb.cpp
new file mode 100644
index 00000000000..8185669e2f4
--- /dev/null
+++ b/cpp/src/Freeze/SharedDb.cpp
@@ -0,0 +1,170 @@
+// **********************************************************************
+//
+// Copyright (c) 2003
+// ZeroC, Inc.
+// Billerica, MA, USA
+//
+// All Rights Reserved.
+//
+// Ice is free software; you can redistribute it and/or modify it under
+// the terms of the GNU General Public License version 2 as published by
+// the Free Software Foundation.
+//
+// **********************************************************************
+
+#include <Freeze/SharedDb.h>
+#include <IceUtil/StaticMutex.h>
+#include <Freeze/DBException.h>
+#include <sys/stat.h>
+
+using namespace std;
+using namespace IceUtil;
+using namespace Ice;
+
+#ifdef _WIN32
+#   define FREEZE_DB_MODE 0
+#else
+#   define FREEZE_DB_MODE (S_IRUSR | S_IWUSR)
+#endif
+
+namespace
+{
+
+StaticMutex _mapMutex = ICE_STATIC_MUTEX_INITIALIZER;
+StaticMutex _refCountMutex = ICE_STATIC_MUTEX_INITIALIZER;  
+
+}
+
+Freeze::SharedDb::Map* Freeze::SharedDb::sharedDbMap = 0;
+
+Freeze::SharedDbPtr 
+Freeze::SharedDb::get(const ConnectionIPtr& connection, 
+		      const string& dbName, bool createDb)
+{
+    StaticMutex::Lock lock(_mapMutex);
+
+    if(sharedDbMap == 0)
+    {
+	sharedDbMap = new Map;
+    }
+
+    MapKey key;
+    key.envName = connection->envName();
+    key.communicator = connection->communicator();
+    key.dbName = dbName;
+
+    {
+	Map::iterator p = sharedDbMap->find(key);
+	if(p != sharedDbMap->end())
+	{
+	    return p->second;
+	}
+    }
+
+    //
+    // MapKey not found, let's create and open a new Db
+    //
+    auto_ptr<SharedDb> result(new SharedDb(key, connection, createDb));
+    
+    //
+    // Insert it into the map
+    //
+    pair<Map::iterator, bool> insertResult = sharedDbMap->insert(Map::value_type(key, result.get()));
+    assert(insertResult.second);
+    
+    return result.release();
+}
+
+Freeze::SharedDb::~SharedDb()
+{
+    if(_trace >= 1)
+    {
+	Trace out(_key.communicator->getLogger(), "DB");
+	out << "closing database \"" << _key.dbName << "\"";
+    }
+
+    try
+    {
+	close(0);
+    }
+    catch(const ::DbException& dx)
+    {
+	DBException ex(__FILE__, __LINE__);
+	ex.message = dx.what();
+	throw ex;
+    }
+
+}
+
+void Freeze::SharedDb::__incRef()
+{
+    IceUtil::StaticMutex::Lock lock(_refCountMutex);
+    _refCount++;
+}
+
+void Freeze::SharedDb::__decRef()
+{
+    IceUtil::StaticMutex::Lock lock(_refCountMutex);
+    if(--_refCount == 0)
+    {
+        IceUtil::StaticMutex::TryLock mapLock(_mapMutex);
+	if(!mapLock.acquired())
+	{
+	    //
+	    // Reacquire mutex in proper order and check again
+	    //
+	    lock.release();
+	    mapLock.acquire();
+	    lock.acquire();
+	    if(_refCount > 0)
+	    {
+		return;
+	    }
+	}
+
+	//
+	// Remove from map
+	//
+	size_t one = sharedDbMap->erase(_key);
+	assert(one == 1);
+
+	if(sharedDbMap->size() == 0)
+	{
+	    delete sharedDbMap;
+	    sharedDbMap = 0;
+	}
+
+	//
+	// Keep lock to prevent somebody else to re-open this Db
+	// before it's closed.
+	//
+	delete this;
+    }
+}
+
+
+  
+Freeze::SharedDb::SharedDb(const MapKey& key, 
+			   const ConnectionIPtr& connection, 
+			   bool createDb) :
+    Db(connection->dbEnv(), 0),
+    _key(key),
+    _refCount(0),
+    _trace(connection->trace())
+{
+    try
+    {
+	u_int32_t flags = DB_AUTO_COMMIT | DB_THREAD;
+	if(createDb)
+	{
+	    flags |= DB_CREATE;
+	}
+	open(0, key.dbName.c_str(), 0, DB_BTREE, flags, FREEZE_DB_MODE);
+    }
+    catch(const ::DbException& dx)
+    {
+	DBException ex(__FILE__, __LINE__);
+	ex.message = dx.what();
+	throw ex;
+    }
+}