diff --git a/src/AbstractBtMessage.cc b/src/AbstractBtMessage.cc
index f4fef342..d1c76a7e 100644
--- a/src/AbstractBtMessage.cc
+++ b/src/AbstractBtMessage.cc
@@ -45,6 +45,7 @@ AbstractBtMessage::AbstractBtMessage(uint8_t id, const char* name)
     uploading_(false),
     cuid_(0),
     name_(name),
+    pieceStorage_(0),
     dispatcher_(0),
     messageFactory_(0),
     requestFactory_(0),
@@ -71,8 +72,7 @@ AbstractBtMessage::setBtMessageValidator(const std::shared_ptr<BtMessageValidato
   validator_ = validator;
 }
 
-void AbstractBtMessage::setPieceStorage
-(const std::shared_ptr<PieceStorage>& pieceStorage)
+void AbstractBtMessage::setPieceStorage(PieceStorage* pieceStorage)
 {
   pieceStorage_ = pieceStorage;
 }
diff --git a/src/AbstractBtMessage.h b/src/AbstractBtMessage.h
index 49a1b2ed..c37ad69f 100644
--- a/src/AbstractBtMessage.h
+++ b/src/AbstractBtMessage.h
@@ -56,7 +56,7 @@ private:
 
   const char* name_;
 
-  std::shared_ptr<PieceStorage> pieceStorage_;
+  PieceStorage* pieceStorage_;
 
   std::shared_ptr<Peer> peer_;
 
@@ -72,7 +72,7 @@ private:
 
   bool metadataGetMode_;
 protected:
-  const std::shared_ptr<PieceStorage>& getPieceStorage() const
+  PieceStorage* getPieceStorage() const
   {
     return pieceStorage_;
   }
@@ -153,7 +153,7 @@ public:
 
   void setBtMessageValidator(const std::shared_ptr<BtMessageValidator>& validator);
 
-  void setPieceStorage(const std::shared_ptr<PieceStorage>& pieceStorage);
+  void setPieceStorage(PieceStorage* pieceStorage);
 
   void setBtMessageDispatcher(BtMessageDispatcher* dispatcher);
 
diff --git a/src/BtInterestedMessage.cc b/src/BtInterestedMessage.cc
index e70b79b4..e4e92e63 100644
--- a/src/BtInterestedMessage.cc
+++ b/src/BtInterestedMessage.cc
@@ -41,7 +41,10 @@ namespace aria2 {
 
 const char BtInterestedMessage::NAME[] = "interested";
 
-BtInterestedMessage::BtInterestedMessage():ZeroBtMessage(ID, NAME) {}
+BtInterestedMessage::BtInterestedMessage()
+  : ZeroBtMessage(ID, NAME),
+    peerStorage_(0)
+{}
 
 BtInterestedMessage::~BtInterestedMessage() {}
 
@@ -86,8 +89,7 @@ ProgressUpdate* BtInterestedMessage::getProgressUpdate()
   return new ThisProgressUpdate(getPeer());
 }
 
-void BtInterestedMessage::setPeerStorage
-(const std::shared_ptr<PeerStorage>& peerStorage)
+void BtInterestedMessage::setPeerStorage(PeerStorage* peerStorage)
 {
   peerStorage_ = peerStorage;
 }
diff --git a/src/BtInterestedMessage.h b/src/BtInterestedMessage.h
index 392086f3..0f794126 100644
--- a/src/BtInterestedMessage.h
+++ b/src/BtInterestedMessage.h
@@ -44,7 +44,7 @@ class BtInterestedMessage;
 
 class BtInterestedMessage : public ZeroBtMessage {
 private:
-  std::shared_ptr<PeerStorage> peerStorage_;
+  PeerStorage* peerStorage_;
 public:
   BtInterestedMessage();
   virtual ~BtInterestedMessage();
@@ -62,7 +62,7 @@ public:
 
   virtual ProgressUpdate* getProgressUpdate();
 
-  void setPeerStorage(const std::shared_ptr<PeerStorage>& peerStorage);
+  void setPeerStorage(PeerStorage* peerStorage);
 };
 
 } // namespace aria2
diff --git a/src/BtNotInterestedMessage.cc b/src/BtNotInterestedMessage.cc
index eca078d5..dcd9b810 100644
--- a/src/BtNotInterestedMessage.cc
+++ b/src/BtNotInterestedMessage.cc
@@ -41,7 +41,10 @@ namespace aria2 {
 
 const char BtNotInterestedMessage::NAME[] = "not interested";
 
-BtNotInterestedMessage::BtNotInterestedMessage():ZeroBtMessage(ID, NAME) {}
+BtNotInterestedMessage::BtNotInterestedMessage()
+  : ZeroBtMessage(ID, NAME),
+    peerStorage_(0)
+{}
 
 BtNotInterestedMessage::~BtNotInterestedMessage() {}
 
@@ -86,8 +89,7 @@ ProgressUpdate* BtNotInterestedMessage::getProgressUpdate()
   return new ThisProgressUpdate(getPeer());
 }
 
-void BtNotInterestedMessage::setPeerStorage
-(const std::shared_ptr<PeerStorage>& peerStorage)
+void BtNotInterestedMessage::setPeerStorage(PeerStorage* peerStorage)
 {
   peerStorage_ = peerStorage;
 }
diff --git a/src/BtNotInterestedMessage.h b/src/BtNotInterestedMessage.h
index 0a1f4fd7..d356a802 100644
--- a/src/BtNotInterestedMessage.h
+++ b/src/BtNotInterestedMessage.h
@@ -44,7 +44,7 @@ class BtNotInterestedMessage;
 
 class BtNotInterestedMessage : public ZeroBtMessage {
 private:
-  std::shared_ptr<PeerStorage> peerStorage_;
+  PeerStorage* peerStorage_;
 public:
   BtNotInterestedMessage();
   virtual ~BtNotInterestedMessage();
@@ -62,7 +62,7 @@ public:
 
   virtual ProgressUpdate* getProgressUpdate();
 
-  void setPeerStorage(const std::shared_ptr<PeerStorage>& peerStorage);
+  void setPeerStorage(PeerStorage* peerStorage);
 };
 
 } // namespace aria2
diff --git a/src/BtPieceMessage.cc b/src/BtPieceMessage.cc
index c0abf66b..ec39043e 100644
--- a/src/BtPieceMessage.cc
+++ b/src/BtPieceMessage.cc
@@ -71,7 +71,9 @@ BtPieceMessage::BtPieceMessage
     index_(index),
     begin_(begin),
     blockLength_(blockLength),
-    data_(0)
+    data_(0),
+    downloadContext_(0),
+    peerStorage_(0)
 {
   setUploading(true);
 }
@@ -334,14 +336,12 @@ void BtPieceMessage::onCancelSendingPieceEvent
   }
 }
 
-void BtPieceMessage::setDownloadContext
-(const std::shared_ptr<DownloadContext>& downloadContext)
+void BtPieceMessage::setDownloadContext(DownloadContext* downloadContext)
 {
   downloadContext_ = downloadContext;
 }
 
-void BtPieceMessage::setPeerStorage
-(const std::shared_ptr<PeerStorage>& peerStorage)
+void BtPieceMessage::setPeerStorage(PeerStorage* peerStorage)
 {
   peerStorage_ = peerStorage;
 }
diff --git a/src/BtPieceMessage.h b/src/BtPieceMessage.h
index d6488ba2..41dcfb46 100644
--- a/src/BtPieceMessage.h
+++ b/src/BtPieceMessage.h
@@ -49,8 +49,8 @@ private:
   int32_t begin_;
   int32_t blockLength_;
   const unsigned char* data_;
-  std::shared_ptr<DownloadContext> downloadContext_;
-  std::shared_ptr<PeerStorage> peerStorage_;
+  DownloadContext* downloadContext_;
+  PeerStorage* peerStorage_;
 
   static size_t MESSAGE_HEADER_LENGTH;
 
@@ -88,9 +88,9 @@ public:
 
   void setBlockLength(int32_t blockLength) { blockLength_ = blockLength; }
 
-  void setDownloadContext(const std::shared_ptr<DownloadContext>& downloadContext);
+  void setDownloadContext(DownloadContext* downloadContext);
 
-  void setPeerStorage(const std::shared_ptr<PeerStorage>& peerStorage);
+  void setPeerStorage(PeerStorage* peerStorage);
 
   static BtPieceMessage* create(const unsigned char* data, size_t dataLength);
 
diff --git a/src/DefaultBtMessageFactory.cc b/src/DefaultBtMessageFactory.cc
index 6abe6445..ad2a3cc8 100644
--- a/src/DefaultBtMessageFactory.cc
+++ b/src/DefaultBtMessageFactory.cc
@@ -72,6 +72,9 @@ namespace aria2 {
 
 DefaultBtMessageFactory::DefaultBtMessageFactory():
   cuid_(0),
+  downloadContext_(0),
+  pieceStorage_(0),
+  peerStorage_(0),
   dhtEnabled_(false),
   dispatcher_(0),
   requestFactory_(0),
@@ -439,19 +442,17 @@ void DefaultBtMessageFactory::setPeer(const std::shared_ptr<Peer>& peer)
 }
 
 void DefaultBtMessageFactory::setDownloadContext
-(const std::shared_ptr<DownloadContext>& downloadContext)
+(DownloadContext* downloadContext)
 {
   downloadContext_ = downloadContext;
 }
 
-void DefaultBtMessageFactory::setPieceStorage
-(const std::shared_ptr<PieceStorage>& pieceStorage)
+void DefaultBtMessageFactory::setPieceStorage(PieceStorage* pieceStorage)
 {
   pieceStorage_ = pieceStorage;
 }
 
-void DefaultBtMessageFactory::setPeerStorage
-(const std::shared_ptr<PeerStorage>& peerStorage)
+void DefaultBtMessageFactory::setPeerStorage(PeerStorage* peerStorage)
 {
   peerStorage_ = peerStorage;
 }
diff --git a/src/DefaultBtMessageFactory.h b/src/DefaultBtMessageFactory.h
index df9c08d7..cad09116 100644
--- a/src/DefaultBtMessageFactory.h
+++ b/src/DefaultBtMessageFactory.h
@@ -57,9 +57,9 @@ class DHTTaskFactory;
 class DefaultBtMessageFactory : public BtMessageFactory {
 private:
   cuid_t cuid_;
-  std::shared_ptr<DownloadContext> downloadContext_;
-  std::shared_ptr<PieceStorage> pieceStorage_;
-  std::shared_ptr<PeerStorage> peerStorage_;
+  DownloadContext* downloadContext_;
+  PieceStorage* pieceStorage_;
+  PeerStorage* peerStorage_;
   std::shared_ptr<Peer> peer_;
 
   bool dhtEnabled_;
@@ -137,11 +137,11 @@ public:
 
   void setPeer(const std::shared_ptr<Peer>& peer);
 
-  void setDownloadContext(const std::shared_ptr<DownloadContext>& downloadContext);
+  void setDownloadContext(DownloadContext* downloadContext);
 
-  void setPieceStorage(const std::shared_ptr<PieceStorage>& pieceStorage);
+  void setPieceStorage(PieceStorage* pieceStorage);
 
-  void setPeerStorage(const std::shared_ptr<PeerStorage>& peerStorage);
+  void setPeerStorage(PeerStorage* peerStorage);
 
   void setCuid(cuid_t cuid)
   {
diff --git a/src/PeerInteractionCommand.cc b/src/PeerInteractionCommand.cc
index 5d762023..c9e118c3 100644
--- a/src/PeerInteractionCommand.cc
+++ b/src/PeerInteractionCommand.cc
@@ -147,9 +147,9 @@ PeerInteractionCommand::PeerInteractionCommand
 
   DefaultBtMessageFactory* factoryPtr(new DefaultBtMessageFactory());
   factoryPtr->setCuid(cuid);
-  factoryPtr->setDownloadContext(requestGroup_->getDownloadContext());
-  factoryPtr->setPieceStorage(pieceStorage);
-  factoryPtr->setPeerStorage(peerStorage);
+  factoryPtr->setDownloadContext(requestGroup_->getDownloadContext().get());
+  factoryPtr->setPieceStorage(pieceStorage.get());
+  factoryPtr->setPeerStorage(peerStorage.get());
   factoryPtr->setExtensionMessageFactory(extensionMessageFactory);
   factoryPtr->setPeer(getPeer());
   if(family == AF_INET) {
diff --git a/src/bittorrent_helper.cc b/src/bittorrent_helper.cc
index 4850ea56..07e9259f 100644
--- a/src/bittorrent_helper.cc
+++ b/src/bittorrent_helper.cc
@@ -623,13 +623,23 @@ void loadFromMemory(const std::shared_ptr<ValueBase>& torrent,
 
 std::shared_ptr<TorrentAttribute> getTorrentAttrs
 (const std::shared_ptr<DownloadContext>& dctx)
+{
+  return getTorrentAttrs(dctx.get());
+}
+
+std::shared_ptr<TorrentAttribute> getTorrentAttrs(DownloadContext* dctx)
 {
   return std::static_pointer_cast<TorrentAttribute>
     (dctx->getAttribute(CTX_ATTR_BT));
 }
 
-const unsigned char*
-getInfoHash(const std::shared_ptr<DownloadContext>& dctx)
+const unsigned char* getInfoHash
+(const std::shared_ptr<DownloadContext>& dctx)
+{
+  return getInfoHash(dctx.get());
+}
+
+const unsigned char* getInfoHash(DownloadContext* dctx)
 {
   return reinterpret_cast<const unsigned char*>
     (getTorrentAttrs(dctx)->infoHash.data());
@@ -637,6 +647,12 @@ getInfoHash(const std::shared_ptr<DownloadContext>& dctx)
 
 std::string
 getInfoHashString(const std::shared_ptr<DownloadContext>& dctx)
+{
+  return getInfoHashString(dctx.get());
+}
+
+std::string
+getInfoHashString(DownloadContext* dctx)
 {
   return util::toHex(getTorrentAttrs(dctx)->infoHash);
 }
diff --git a/src/bittorrent_helper.h b/src/bittorrent_helper.h
index d26d3af1..74d983f7 100644
--- a/src/bittorrent_helper.h
+++ b/src/bittorrent_helper.h
@@ -149,16 +149,19 @@ void computeFastSet
 (std::vector<size_t>& fastSet, const std::string& ipaddr,
  size_t numPieces, const unsigned char* infoHash, size_t fastSetSize);
 
+std::shared_ptr<TorrentAttribute> getTorrentAttrs(DownloadContext* dctx);
 std::shared_ptr<TorrentAttribute> getTorrentAttrs
 (const std::shared_ptr<DownloadContext>& dctx);
 
 // Returns the value associated with INFO_HASH key in BITTORRENT
 // attribute.
-const unsigned char*
-getInfoHash(const std::shared_ptr<DownloadContext>& downloadContext);
+const unsigned char* getInfoHash(DownloadContext* downloadContext);
+const unsigned char* getInfoHash
+(const std::shared_ptr<DownloadContext>& downloadContext);
 
-std::string
-getInfoHashString(const std::shared_ptr<DownloadContext>& downloadContext);
+std::string getInfoHashString(DownloadContext* downloadContext);
+std::string getInfoHashString
+(const std::shared_ptr<DownloadContext>& downloadContext);
 
 // Returns 8bytes unsigned integer located at offset pos.  The integer
 // in msg is network byte order. This function converts it into host
diff --git a/test/BtBitfieldMessageTest.cc b/test/BtBitfieldMessageTest.cc
index 475c8a46..9331b94b 100644
--- a/test/BtBitfieldMessageTest.cc
+++ b/test/BtBitfieldMessageTest.cc
@@ -85,8 +85,8 @@ void BtBitfieldMessageTest::testDoReceivedAction() {
   peer->allocateSessionResource(16*1024, 16*16*1024);
   BtBitfieldMessage msg;
   msg.setPeer(peer);
-  std::shared_ptr<MockPieceStorage> pieceStorage(new MockPieceStorage());
-  msg.setPieceStorage(pieceStorage);
+  auto pieceStorage = make_unique<MockPieceStorage>();
+  msg.setPieceStorage(pieceStorage.get());
   unsigned char bitfield[] = { 0xff, 0xff };
   msg.setBitfield(bitfield, sizeof(bitfield));
 
@@ -103,8 +103,8 @@ void BtBitfieldMessageTest::testDoReceivedAction_goodByeSeeder()
   peer->allocateSessionResource(1024, 1024);
   BtBitfieldMessage msg;
   msg.setPeer(peer);
-  std::shared_ptr<MockPieceStorage> pieceStorage(new MockPieceStorage());
-  msg.setPieceStorage(pieceStorage);
+  auto pieceStorage = make_unique<MockPieceStorage>();
+  msg.setPieceStorage(pieceStorage.get());
   unsigned char bitfield[] = { 0x00 };
   msg.setBitfield(bitfield, sizeof(bitfield));
 
diff --git a/test/BtHaveAllMessageTest.cc b/test/BtHaveAllMessageTest.cc
index 0b6a9e92..5e8987c6 100644
--- a/test/BtHaveAllMessageTest.cc
+++ b/test/BtHaveAllMessageTest.cc
@@ -74,8 +74,8 @@ void BtHaveAllMessageTest::testDoReceivedAction() {
   peer->allocateSessionResource(16*1024, 256*1024);
   peer->setFastExtensionEnabled(true);
   msg.setPeer(peer);
-  std::shared_ptr<MockPieceStorage> pieceStorage(new MockPieceStorage());
-  msg.setPieceStorage(pieceStorage);
+  auto pieceStorage = make_unique<MockPieceStorage>();
+  msg.setPieceStorage(pieceStorage.get());
 
   msg.doReceivedAction();
 
@@ -96,8 +96,8 @@ void BtHaveAllMessageTest::testDoReceivedAction_goodByeSeeder()
   peer->allocateSessionResource(1024, 1024);
   peer->setFastExtensionEnabled(true);
   msg.setPeer(peer);
-  std::shared_ptr<MockPieceStorage> pieceStorage(new MockPieceStorage());
-  msg.setPieceStorage(pieceStorage);
+  auto pieceStorage = make_unique<MockPieceStorage>();
+  msg.setPieceStorage(pieceStorage.get());
 
   pieceStorage->setDownloadFinished(true);
 
diff --git a/test/BtHaveMessageTest.cc b/test/BtHaveMessageTest.cc
index 15072e24..9e78ee9f 100644
--- a/test/BtHaveMessageTest.cc
+++ b/test/BtHaveMessageTest.cc
@@ -80,8 +80,8 @@ void BtHaveMessageTest::testDoReceivedAction() {
   BtHaveMessage msg;
   msg.setIndex(1);
   msg.setPeer(peer);
-  std::shared_ptr<MockPieceStorage> pieceStorage(new MockPieceStorage());
-  msg.setPieceStorage(pieceStorage);
+  auto pieceStorage = make_unique<MockPieceStorage>();
+  msg.setPieceStorage(pieceStorage.get());
 
   CPPUNIT_ASSERT(!peer->hasPiece(msg.getIndex()));
 
@@ -97,8 +97,8 @@ void BtHaveMessageTest::testDoReceivedAction_goodByeSeeder()
   BtHaveMessage msg;
   msg.setIndex(0);
   msg.setPeer(peer);
-  std::shared_ptr<MockPieceStorage> pieceStorage(new MockPieceStorage());
-  msg.setPieceStorage(pieceStorage);
+  auto pieceStorage = make_unique<MockPieceStorage>();
+  msg.setPieceStorage(pieceStorage.get());
 
   // peer is not seeder and client have not completed download
   msg.doReceivedAction();
diff --git a/test/BtInterestedMessageTest.cc b/test/BtInterestedMessageTest.cc
index 0cf47318..1dc5e5a7 100644
--- a/test/BtInterestedMessageTest.cc
+++ b/test/BtInterestedMessageTest.cc
@@ -71,9 +71,9 @@ void BtInterestedMessageTest::testDoReceivedAction() {
   peer->allocateSessionResource(1024, 1024*1024);
   msg.setPeer(peer);
 
-  std::shared_ptr<MockPeerStorage> peerStorage(new MockPeerStorage());
+  auto peerStorage = make_unique<MockPeerStorage>();
 
-  msg.setPeerStorage(peerStorage);
+  msg.setPeerStorage(peerStorage.get());
 
   CPPUNIT_ASSERT(!peer->peerInterested());
   msg.doReceivedAction();
diff --git a/test/BtNotInterestedMessageTest.cc b/test/BtNotInterestedMessageTest.cc
index 01c1727e..181c5665 100644
--- a/test/BtNotInterestedMessageTest.cc
+++ b/test/BtNotInterestedMessageTest.cc
@@ -70,11 +70,11 @@ void BtNotInterestedMessageTest::testDoReceivedAction() {
   peer->allocateSessionResource(1024, 1024*1024);
   peer->peerInterested(true);
 
-  std::shared_ptr<MockPeerStorage> peerStorage(new MockPeerStorage());
+  auto peerStorage = make_unique<MockPeerStorage>();
 
   BtNotInterestedMessage msg;
   msg.setPeer(peer);
-  msg.setPeerStorage(peerStorage);
+  msg.setPeerStorage(peerStorage.get());
 
   CPPUNIT_ASSERT(peer->peerInterested());
   msg.doReceivedAction();
diff --git a/test/BtPieceMessageTest.cc b/test/BtPieceMessageTest.cc
index fc88fc84..d758d53c 100644
--- a/test/BtPieceMessageTest.cc
+++ b/test/BtPieceMessageTest.cc
@@ -88,7 +88,7 @@ public:
     msg->setIndex(1);
     msg->setBegin(1024);
     msg->setBlockLength(16*1024);
-    msg->setDownloadContext(dctx_);
+    msg->setDownloadContext(dctx_.get());
     msg->setPeer(peer);
     msg->setBtMessageDispatcher(btMessageDispatcher.get());
     msg->setBtMessageFactory(btMessageFactory_.get());
diff --git a/test/BtRequestMessageTest.cc b/test/BtRequestMessageTest.cc
index 623851e4..b56dce54 100644
--- a/test/BtRequestMessageTest.cc
+++ b/test/BtRequestMessageTest.cc
@@ -117,7 +117,7 @@ public:
     msg->setBlockIndex(2);
     msg->setBtMessageDispatcher(dispatcher_.get());
     msg->setBtMessageFactory(messageFactory_.get());
-    msg->setPieceStorage(pieceStorage_);
+    msg->setPieceStorage(pieceStorage_.get());
   }
 };
 
diff --git a/test/DefaultBtMessageFactoryTest.cc b/test/DefaultBtMessageFactoryTest.cc
index 94f6d87f..cf4c6954 100644
--- a/test/DefaultBtMessageFactoryTest.cc
+++ b/test/DefaultBtMessageFactoryTest.cc
@@ -40,7 +40,7 @@ public:
     exmsgFactory_.reset(new MockExtensionMessageFactory());
 
     factory_.reset(new DefaultBtMessageFactory());
-    factory_->setDownloadContext(dctx_);
+    factory_->setDownloadContext(dctx_.get());
     factory_->setPeer(peer_);
     factory_->setExtensionMessageFactory(exmsgFactory_);
   }