Adapt sync to use new ndn.cxx api
diff --git a/src/ccnx/sync-app-socket-c.cc b/src/ccnx/sync-app-socket-c.cc
deleted file mode 100644
index e23c8d1..0000000
--- a/src/ccnx/sync-app-socket-c.cc
+++ /dev/null
@@ -1,146 +0,0 @@
-/* -*- Mode: C++; c-file-style: "gnu"; indent-tabs-mode:nil -*- */
-/*
- * Copyright (c) 2012 University of California, Los Angeles
- *
- * This program 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;
- *
- * 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
- *
- * Author: Zhenkai Zhu <zhenkai@cs.ucla.edu>
- *         Chaoyi Bian <bcy@pku.edu.cn>
- *	   Alexander Afanasyev <alexander.afanasyev@ucla.edu>
- */
-
-#include "sync-app-socket.h"
-#include <boost/shared_array.hpp>
-using namespace std;
-using namespace Sync;
-
-struct SyncAppSocketStruct;
-struct MissingDataInfoC
-{
-  const char *prefix;
-  int session;
-  int low;
-  int high;
-};
-
-class CallbackHolder {
-private:
-  void (*m_callback)(const char *, const char *);
-
-public:
-  CallbackHolder(void (*callback)(const char*, const char*))
-    :m_callback(callback){};
-  
-  void callbackWrapper(const string &name, const string &data) {
-    if (m_callback != NULL)
-      (*m_callback)(name.c_str(), data.c_str());
-  }
-};
-
-class UpdateCallbackHolder {
-private:
-  void (*m_callback)(const struct MissingDataInfoC*, const int, const SyncAppSocketStruct*);
-
-public:
-  UpdateCallbackHolder(void (*callback)(
-        const MissingDataInfoC*, 
-        const int, 
-        const SyncAppSocketStruct*))
-    :m_callback(callback){};
-
-  void callbackWrapper(const vector<MissingDataInfo> &mdi, SyncAppSocket* socket) {
-    boost::shared_array<MissingDataInfoC> mdic(new MissingDataInfoC[mdi.size()]);
-    int i;
-    
-    for (i = 0; i < mdi.size(); i++)
-    {
-      mdic[i].prefix = mdi[i].prefix.c_str();
-      mdic[i].session = mdi[i].high.getSession();
-      if (mdi[i].low.getSession() != mdi[i].high.getSession())
-        mdic[i].low = 0;
-      else
-        mdic[i].low = mdi[i].low.getSeq();
-      mdic[i].high = mdi[i].high.getSeq();
-    }
-    if (m_callback != NULL)
-      (*m_callback)(mdic.get(), i, (const SyncAppSocketStruct*) socket);
-  }
-};
-
-class RemoveCallbackHolder {
-private:
-  void (*m_callback)(const char*);
-
-public:
-  RemoveCallbackHolder(void (*callback)(const char*)):m_callback(callback){};
-  void callbackWrapper(const string &prefix) {
-    if (m_callback != NULL)
-      (*m_callback)(prefix.c_str());
-  }
-};
-
-extern "C"
-SyncAppSocketStruct *
-create_sync_app_socket(const char *prefix, 
-    void (*updatecallback)(const MissingDataInfoC*, const int, const SyncAppSocketStruct*),
-    void (*removecallback)(const char *))
-{
-  boost::shared_ptr<UpdateCallbackHolder> uh(new UpdateCallbackHolder(updatecallback));
-  boost::shared_ptr<RemoveCallbackHolder> rh(new RemoveCallbackHolder(removecallback));
-  boost::function<void (const vector<MissingDataInfo>&, SyncAppSocket*)> ucb = bind(&UpdateCallbackHolder::callbackWrapper, uh, _1, _2);
-  boost::function<void (const string&)> rcb = bind(&RemoveCallbackHolder::callbackWrapper, rh, _1);
-  SyncAppSocket *sock = new SyncAppSocket(prefix, ucb, rcb);
-  return (SyncAppSocketStruct *) sock;
-}
-
-extern "C"
-void
-delete_sync_app_socket(SyncAppSocketStruct **sock) {
-  SyncAppSocket *temp = *((SyncAppSocket **)sock);
-  delete temp;
-  temp = NULL;
-}
-
-// assume char *buf ends with '\0', or otherwise it's going to crash;
-// should fix this "feature"
-extern "C" 
-int
-sync_app_socket_publish(const SyncAppSocketStruct *sock, const char *prefix, int session, const char *buf, int freshness) 
-{
-  SyncAppSocket *temp = (SyncAppSocket*) sock;
-  return temp->publishString(prefix, session, buf, freshness);
-}
-
-extern "C"
-void
-sync_app_socket_remove(const SyncAppSocketStruct *sock, const char *prefix) 
-{
-  SyncAppSocket *temp = (SyncAppSocket*) sock;
-  temp->remove(prefix);
-}
-
-extern "C"
-void
-sync_app_socket_fetch(const SyncAppSocketStruct *sock, const char *prefix, int session, int sequence, 
-    void (*callback)(const char*, const char*), int retry)
-{
-  SyncAppSocket *temp = (SyncAppSocket*) sock;
-  string s(prefix);
-  SeqNo seq(session, sequence);
-  boost::shared_ptr<CallbackHolder> h(new CallbackHolder(callback));
-  boost::function<void (const string&, const string&)> cb = bind(&CallbackHolder::callbackWrapper, h, _1, _2);
-
-  temp->fetchString(s, seq, cb, retry);
-}
-
diff --git a/src/ccnx/sync-app-socket-c.h b/src/ccnx/sync-app-socket-c.h
deleted file mode 100644
index 7ab9e70..0000000
--- a/src/ccnx/sync-app-socket-c.h
+++ /dev/null
@@ -1,52 +0,0 @@
-/* -*- Mode: C++; c-file-style: "gnu"; indent-tabs-mode:nil -*- */
-/*
- * Copyright (c) 2012 University of California, Los Angeles
- *
- * This program 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;
- *
- * 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
- *
- * Author: Zhenkai Zhu <zhenkai@cs.ucla.edu>
- *         Chaoyi Bian <bcy@pku.edu.cn>
- *	   Alexander Afanasyev <alexander.afanasyev@ucla.edu>
- */
-
-#ifndef SYNC_APP_SOCKET_C_H
-#define SYNC_APP_SOCKET_C_H
-
-#ifdef __cplusplus
-extern "C" {
-#endif
-  
-  typedef struct SyncAppSocketStruct SyncAppSocketStruct;
-  
-  struct MissingDataInfoC
-  {
-    const char *prefix;
-    int session;
-    int low;
-    int high;
-  };
-
-  SyncAppSocketStruct *create_sync_app_socket(const char *prefix, 
-      void (*updatecallback)(const struct MissingDataInfoC*, const int, const SyncAppSocketStruct*),
-      void (*removecallback)(const char *));
-  void delete_sync_app_socket(SyncAppSocketStruct **sock);
-  int sync_app_socket_publish(const SyncAppSocketStruct *sock, const char *prefix, int session, const char *buf, int freshness);
-  void sync_app_socket_remove(const SyncAppSocketStruct *sock, const char *prefix);
-  void sync_app_socket_fetch(const SyncAppSocketStruct *sock, const char *prefix, int session, int seq,
-      void (*callback)(const char*, const char*), int retry);
-#ifdef __cplusplus
-}
-#endif
-
-#endif // SYNC_APP_SOCKET_C_H
diff --git a/src/ccnx/sync-app-socket.cc b/src/ccnx/sync-app-socket.cc
deleted file mode 100644
index 0e4e829..0000000
--- a/src/ccnx/sync-app-socket.cc
+++ /dev/null
@@ -1,115 +0,0 @@
-/* -*- Mode: C32++; c-file-style: "gnu"; indent-tabs-mode:nil -*- */
-/*
- * Copyright (c) 2012 University of California, Los Angeles
- *
- * This program 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;
- *
- * 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
- *
- * Author: Zhenkai Zhu <zhenkai@cs.ucla.edu>
- *         Chaoyi Bian <bcy@pku.edu.cn>
- *	   Alexander Afanasyev <alexander.afanasyev@ucla.edu>
- */
-
-#include "sync-app-socket.h"
-
-using namespace std;
-using namespace boost;
-
-namespace Sync
-{
-
-SyncAppSocket::SyncAppSocket (const string &syncPrefix, NewDataCallback dataCallback, RemoveCallback rmCallback )
-  : m_newDataCallback(dataCallback)
-  , m_ccnxHandle (new CcnxWrapper())
-  , m_syncLogic (syncPrefix,
-                 bind(&SyncAppSocket::passCallback, this, _1),
-                 rmCallback)
-{
-}
-
-SyncAppSocket::~SyncAppSocket()
-{
-}
-
-std::string
-SyncAppSocket::GetLocalPrefix()
-{
-  // this handle is supposed to be short lived
-  CcnxWrapperPtr handle( new CcnxWrapper());
-  return handle->getLocalPrefix();
-}
-
-bool 
-SyncAppSocket::publishString (const string &prefix, uint32_t session, const string &dataBuffer, int freshness)
-{
-  uint32_t sequence = getNextSeq(prefix, session);
-  ostringstream contentNameWithSeqno;
-  contentNameWithSeqno << prefix << "/" << session << "/" << sequence;
-  m_ccnxHandle->publishStringData (contentNameWithSeqno.str (), dataBuffer, freshness);
-
-  SeqNo s(session, sequence + 1);
-  m_sequenceLog[prefix] = s;
-
-  m_syncLogic.addLocalNames (prefix, session, sequence);
-  return true;
-}
-
-bool 
-SyncAppSocket::publishRaw(const std::string &prefix, uint32_t session, const char *buf, size_t len, int freshness)
-{
-  uint32_t sequence = getNextSeq(prefix, session);
-  ostringstream contentNameWithSeqno;
-  contentNameWithSeqno << prefix << "/" << session << "/" << sequence;
-
-  m_ccnxHandle->publishRawData (contentNameWithSeqno.str (), buf, len, freshness);
-
-  SeqNo s(session, sequence + 1);
-  m_sequenceLog[prefix] = s;
-  m_syncLogic.addLocalNames (prefix, session, sequence);
-  return true;
-}
-
-
-void 
-SyncAppSocket::fetchString(const std::string &prefix, const SeqNo &seq, CcnxWrapper::StringDataCallback callback, int retry)
-{
-  ostringstream interestName;
-  interestName << prefix << "/" << seq.getSession() << "/" << seq.getSeq();
-  m_ccnxHandle->sendInterestForString(interestName.str(), callback, retry);
-}
-
-void 
-SyncAppSocket::fetchRaw(const std::string &prefix, const SeqNo &seq, CcnxWrapper::RawDataCallback callback, int retry)
-{
-  ostringstream interestName;
-  interestName << prefix << "/" << seq.getSession() << "/" << seq.getSeq();
-  //std::cout << "Socket " << this << " Send Interest <" << interestName.str() << "> for raw data " << endl;
-  m_ccnxHandle->sendInterest(interestName.str(), callback, retry);
-}
-
-uint32_t
-SyncAppSocket::getNextSeq (const string &prefix, uint32_t session)
-{
-  SequenceLog::iterator i = m_sequenceLog.find (prefix);
-
-  if (i != m_sequenceLog.end ())
-    {
-      SeqNo s = i->second;
-      if (s.getSession() == session)
-        return s.getSeq();
-    }
-  return 0;
-}
-
-}
-
diff --git a/src/ccnx/sync-app-socket.h b/src/ccnx/sync-app-socket.h
deleted file mode 100644
index ceeb5ce..0000000
--- a/src/ccnx/sync-app-socket.h
+++ /dev/null
@@ -1,112 +0,0 @@
-/* -*- Mode: C++; c-file-style: "gnu"; indent-tabs-mode:nil -*- */
-/*
- * Copyright (c) 2012 University of California, Los Angeles
- *
- * This program 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;
- *
- * 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
- *
- * Author: Zhenkai Zhu <zhenkai@cs.ucla.edu>
- *         Chaoyi Bian <bcy@pku.edu.cn>
- *	   Alexander Afanasyev <alexander.afanasyev@ucla.edu>
- */
-
-#ifndef SYNC_APP_SOCKET_H
-#define SYNC_APP_SOCKET_H
-
-#include "sync-logic.h"
-#include <boost/function.hpp>
-#include <boost/unordered_map.hpp>
-#include "sync-seq-no.h"
-#include "sync-ccnx-wrapper.h"
-#include <utility>
-#include <map>
-#include <vector>
-#include <sstream>
-
-namespace Sync {
-
-/**
- * \ingroup sync
- * @brief A simple interface to interact with client code
- */
-class SyncAppSocket
-{
-public:
-  typedef boost::function< void (const std::vector<MissingDataInfo> &, SyncAppSocket * ) > NewDataCallback;
-  typedef boost::function< void ( const std::string &/*prefix*/ ) > RemoveCallback;
-  /**
-   * @brief the constructor for SyncAppSocket; the parameter syncPrefix
-   * should be passed to the constructor of m_syncAppWrapper; the other
-   * parameter should be passed to the constructor of m_fetcher; furthermore,
-   * the fetch function of m_fetcher should be a second paramter passed to
-   * the constructor of m_syncAppWrapper, so that m_syncAppWrapper can tell
-   * m_fetcher to fetch the actual app data after it learns the names
-   *
-   * @param syncPrefix the name prefix for Sync Interest
-   * @param dataCallback the callback to process data
-   */
-  SyncAppSocket (const std::string &syncPrefix, NewDataCallback dataCallback, RemoveCallback rmCallback);
-  ~SyncAppSocket ();
-
-  /**
-   * @brief publish data from local client and tell SyncLogic to update
-   * the sync tree by adding the local names
-   *
-   * @param prefix the name prefix for the data
-   * @param session session to which data is published
-   * @param dataBuffer the data itself
-   * @param freshness the freshness time for the data (in seconds)
-   */
-  bool publishString (const std::string &prefix, uint32_t session, const std::string &dataBuffer, int freshness);
-
-  bool publishRaw(const std::string &prefix, uint32_t session, const char *buf, size_t len, int freshness);
-
-  /**
-   * @brief delete a participant's subtree from the sync tree; SyncLogic will do the work
-   * this is just a wrapper
-   *
-   * @param prefix the prefix for the participant
-   */
-  void remove (const std::string &prefix) {m_syncLogic.remove(prefix);}
-
-  void fetchString(const std::string &prefix, const SeqNo &seq, CcnxWrapper::StringDataCallback callback, int retry = 0);
-  void fetchRaw(const std::string &prefix, const SeqNo &seq, CcnxWrapper::RawDataCallback callback, int retry = 0);
-
-  // for sync-demo
-  std::string getRootDigest() {return m_syncLogic.getRootDigest();}
-  uint32_t
-  getNextSeq (const std::string &prefix, uint32_t session);
-
-  SyncLogic &
-  getLogic () { return m_syncLogic; }
-
-  // make this a static function so we don't have to create socket instance without
-  // knowing the local prefix. it's a wrong place for this function anyway
-  static std::string
-  GetLocalPrefix (); 
-  
-private:
-  void 
-  passCallback(const std::vector<MissingDataInfo> &v) {m_newDataCallback(v, this);}
-
-private:
-  typedef boost::unordered_map<std::string, SeqNo> SequenceLog;
-  NewDataCallback m_newDataCallback;
-  SequenceLog m_sequenceLog;
-  CcnxWrapperPtr m_ccnxHandle;
-  SyncLogic      m_syncLogic;
-};
-
-} // Sync
-
-#endif // SYNC_APP_SOCKET_H
diff --git a/src/ccnx/sync-ccnx-wrapper.cc b/src/ccnx/sync-ccnx-wrapper.cc
deleted file mode 100644
index c824e72..0000000
--- a/src/ccnx/sync-ccnx-wrapper.cc
+++ /dev/null
@@ -1,597 +0,0 @@
-/* -*- Mode: C++; c-file-style: "gnu"; indent-tabs-mode:nil -*- */
-/*
- * Copyright (c) 2012 University of California, Los Angeles
- *
- * This program 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;
- *
- * 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
- *
- * Author: Zhenkai Zhu <zhenkai@cs.ucla.edu>
- *         Chaoyi Bian <bcy@pku.edu.cn>
- *	   Alexander Afanasyev <alexander.afanasyev@ucla.edu>
- */
-
-#include "sync-ccnx-wrapper.h"
-
-extern "C" {
-#include <ccn/fetch.h>
-}
-
-#include "sync-logging.h"
-#include <poll.h>
-#include <boost/throw_exception.hpp>
-#include <boost/date_time/posix_time/posix_time.hpp>
-#include <boost/random.hpp>
-
-#include "sync-scheduler.h"
-
-typedef boost::error_info<struct tag_errmsg, std::string> errmsg_info_str;
-typedef boost::error_info<struct tag_errmsg, int> errmsg_info_int;
-
-
-using namespace std;
-using namespace boost;
-
-INIT_LOGGER ("CcnxWrapper");
-
-namespace Sync {
-
-#ifdef _DEBUG_WRAPPER_      
-CcnxWrapper::CcnxWrapper(char c)
-#else
-CcnxWrapper::CcnxWrapper()
-#endif
-  : m_handle (0)
-  , m_keyStore (0)
-  , m_keyLoactor (0)
-  , m_running (true)
-  , m_connected (false)
-{
-#ifdef _DEBUG_WRAPPER_      
-  m_c = c;
-#endif
-  connectCcnd();
-  initKeyStore ();
-  createKeyLocator ();
-  m_thread = thread (&CcnxWrapper::ccnLoop, this);
-}
-
-void
-CcnxWrapper::connectCcnd()
-{
-  recursive_mutex::scoped_lock lock (m_mutex);
-
-  if (m_handle != 0) {
-    ccn_disconnect (m_handle);
-    ccn_destroy (&m_handle);
-  }
-  
-  m_handle = ccn_create ();
-  _LOG_DEBUG("<<< connecting to ccnd");
-  if (ccn_connect(m_handle, NULL) < 0)
-  {
-    _LOG_DEBUG("<<< connecting to ccnd failed");
-    BOOST_THROW_EXCEPTION (CcnxOperationException() << errmsg_info_str("connection to ccnd failed"));
-  }
-  m_connected = true;
-
-  if (!m_registeredInterests.empty())
-  {
-    for (map<std::string, InterestCallback>::const_iterator it = m_registeredInterests.begin(); it != m_registeredInterests.end(); ++it)
-    {
-      // clearInterestFilter(it->first);
-      setInterestFilter(it->first, it->second);
-      _LOG_DEBUG("<<< registering interest filter for: " << it->first);
-    }
-  }
-}
-
-CcnxWrapper::~CcnxWrapper()
-{
-  // std::cout << "CcnxWrapper::~CcnxWrapper()" << std::endl;
-  {
-    recursive_mutex::scoped_lock lock(m_mutex);
-    m_running = false;
-  }
-  
-  m_thread.join ();
-  ccn_disconnect (m_handle);
-  ccn_destroy (&m_handle);
-  ccn_charbuf_destroy (&m_keyLoactor);
-  ccn_keystore_destroy (&m_keyStore);
-}
-
-/// @cond include_hidden
-
-void
-CcnxWrapper::createKeyLocator ()
-{
-  m_keyLoactor = ccn_charbuf_create();
-  ccn_charbuf_append_tt (m_keyLoactor, CCN_DTAG_KeyLocator, CCN_DTAG);
-  ccn_charbuf_append_tt (m_keyLoactor, CCN_DTAG_Key, CCN_DTAG);
-  int res = ccn_append_pubkey_blob (m_keyLoactor, ccn_keystore_public_key(m_keyStore));
-  if (res >= 0)
-    {
-      ccn_charbuf_append_closer (m_keyLoactor); /* </Key> */
-      ccn_charbuf_append_closer (m_keyLoactor); /* </KeyLocator> */
-    }
-}
-
-const ccn_pkey*
-CcnxWrapper::getPrivateKey ()
-{
-  return ccn_keystore_private_key (m_keyStore);
-}
-
-const unsigned char*
-CcnxWrapper::getPublicKeyDigest ()
-{
-  return ccn_keystore_public_key_digest(m_keyStore);
-}
-
-ssize_t
-CcnxWrapper::getPublicKeyDigestLength ()
-{
-  return ccn_keystore_public_key_digest_length(m_keyStore);
-}
-
-void
-CcnxWrapper::initKeyStore ()
-{
-  m_keyStore = ccn_keystore_create ();
-  string keyStoreFile = string(getenv("HOME")) + string("/.ccnx/.ccnx_keystore");
-  if (ccn_keystore_init (m_keyStore, (char *)keyStoreFile.c_str(), (char*)"Th1s1sn0t8g00dp8ssw0rd.") < 0)
-    BOOST_THROW_EXCEPTION(CcnxOperationException() << errmsg_info_str(keyStoreFile.c_str()));
-}
-
-void
-CcnxWrapper::ccnLoop ()
-{
-  _LOG_FUNCTION (this);
-  static boost::mt19937 randomGenerator (static_cast<unsigned int> (std::time (0)));
-  static boost::variate_generator<boost::mt19937&, boost::uniform_int<> > rangeUniformRandom (randomGenerator, uniform_int<> (0,1000));
-
-  while (m_running)
-    {
-      try
-        {
-#ifdef _DEBUG_WRAPPER_      
-          std::cout << m_c << flush;
-#endif
-          int res = 0;
-          {
-            recursive_mutex::scoped_lock lock (m_mutex);
-            res = ccn_run (m_handle, 0);
-          }
-
-          if (!m_running) break;
-        
-          if (res < 0)
-            BOOST_THROW_EXCEPTION (CcnxOperationException()
-                                 << errmsg_info_str("ccn_run returned error"));
-
-
-          pollfd pfds[1];
-          {
-            recursive_mutex::scoped_lock lock (m_mutex);
-          
-            pfds[0].fd = ccn_get_connection_fd (m_handle);
-            pfds[0].events = POLLIN;
-            if (ccn_output_is_pending (m_handle))
-              pfds[0].events |= POLLOUT;
-          }
-        
-          int ret = poll (pfds, 1, 1);
-          if (ret < 0)
-            {
-              BOOST_THROW_EXCEPTION (CcnxOperationException() << errmsg_info_str("ccnd socket failed (probably ccnd got stopped)"));
-            }
-        }
-        catch (CcnxOperationException &e)
-        {
-          // do not try reconnect for now
-          throw e;
-          /*
-          m_connected = false;
-          // probably ccnd has been stopped
-          // try reconnect with sleep
-          int interval = 1;
-          int maxInterval = 32;
-          while (m_running)
-          {
-            try
-            {
-              this_thread::sleep (boost::get_system_time () + TIME_SECONDS(interval) + TIME_MILLISECONDS (rangeUniformRandom ()));
-
-              connectCcnd();
-              _LOG_DEBUG("reconnect to ccnd succeeded");
-              break;
-            }
-            catch (CcnxOperationException &e)
-            {
-              this_thread::sleep (boost::get_system_time () + TIME_SECONDS(interval) + TIME_MILLISECONDS (rangeUniformRandom ()));
-
-              // do exponential backup for reconnect interval
-              if (interval < maxInterval)
-              {
-                interval *= 2;
-              }
-            }
-          }
-          */
-        }
-        catch (const std::exception &exc)
-          {
-            // catch anything thrown within try block that derives from std::exception
-            std::cerr << exc.what();
-          }
-        catch (...)
-          {
-            cout << "UNKNOWN EXCEPTION !!!" << endl; 
-          }
-          
-     } 
-}
-
-/// @endcond
-int
-CcnxWrapper::publishStringData (const string &name, const string &dataBuffer, int freshness) {
-  return publishRawData(name, dataBuffer.c_str(), dataBuffer.length(), freshness);
-}
-
-int
-CcnxWrapper::publishRawData (const string &name, const char *buf, size_t len, int freshness)
-{
-
-  recursive_mutex::scoped_lock lock(m_mutex);
-  if (!m_running || !m_connected)
-    return -1;
-  
-  // cout << "Publish: " << name << endl;
-  ccn_charbuf *pname = ccn_charbuf_create();
-  ccn_charbuf *signed_info = ccn_charbuf_create();
-  ccn_charbuf *content = ccn_charbuf_create();
-
-  ccn_name_from_uri(pname, name.c_str());
-  ccn_signed_info_create(signed_info,
-			 getPublicKeyDigest(),
-			 getPublicKeyDigestLength(),
-			 NULL,
-			 CCN_CONTENT_DATA,
-			 freshness,
-			 NULL,
-			 m_keyLoactor);
-  if(ccn_encode_ContentObject(content, pname, signed_info,
-			   (const unsigned char *)buf, len,
-			   NULL, getPrivateKey()) < 0)
-  {
-    // BOOST_THROW_EXCEPTION(CcnxOperationException() << errmsg_info_str("encode content failed"));
-    _LOG_ERROR("<<< Encode content failed " << name);
-  }
-
-  if (ccn_put(m_handle, content->buf, content->length) < 0)
-  {
-    // BOOST_THROW_EXCEPTION(CcnxOperationException() << errmsg_info_str("ccnput failed"));
-    _LOG_ERROR("<<< ccnput content failed " << name);
-  }
-
-  ccn_charbuf_destroy (&pname);
-  ccn_charbuf_destroy (&signed_info);
-  ccn_charbuf_destroy (&content);
-  return 0;
-}
-
-
-static ccn_upcall_res
-incomingInterest(ccn_closure *selfp,
-                 ccn_upcall_kind kind,
-                 ccn_upcall_info *info)
-{
-  CcnxWrapper::InterestCallback *f = static_cast<CcnxWrapper::InterestCallback*> (selfp->data);
-
-  switch (kind)
-    {
-    case CCN_UPCALL_FINAL: // effective in unit tests
-      delete f;
-      delete selfp;
-      return CCN_UPCALL_RESULT_OK;
-
-    case CCN_UPCALL_INTEREST:
-      break;
-
-    default:
-      return CCN_UPCALL_RESULT_OK;
-    }
-
-  string interest;
-  for (int i = 0; i < info->interest_comps->n - 1; i++)
-    {
-      char *comp;
-      size_t size;
-      interest += "/";
-      ccn_name_comp_get(info->interest_ccnb, info->interest_comps, i, (const unsigned char **)&comp, &size);
-      string compStr(comp, size);
-      interest += compStr;
-    }
-  (*f) (interest);
-  _LOG_DEBUG("<<< processed interest: " << interest);
-  return CCN_UPCALL_RESULT_OK;
-}
-
-static ccn_upcall_res
-incomingData(ccn_closure *selfp,
-             ccn_upcall_kind kind,
-             ccn_upcall_info *info)
-{
-  ClosurePass *cp = static_cast<ClosurePass *> (selfp->data);
-
-  switch (kind)
-    {
-    case CCN_UPCALL_FINAL:  // effecitve in unit tests
-      delete cp;
-      cp = NULL;
-      delete selfp;
-      return CCN_UPCALL_RESULT_OK;
-
-    case CCN_UPCALL_CONTENT:
-      break;
-
-    case CCN_UPCALL_INTEREST_TIMED_OUT: {
-      if (cp != NULL && cp->getRetry() > 0) {
-        cp->decRetry();
-        return CCN_UPCALL_RESULT_REEXPRESS;
-      }
-      return CCN_UPCALL_RESULT_OK;
-    }
-
-    default:
-      return CCN_UPCALL_RESULT_OK;
-    }
-
-  char *pcontent;
-  size_t len;
-  if (ccn_content_get_value(info->content_ccnb, info->pco->offset[CCN_PCO_E], info->pco, (const unsigned char **)&pcontent, &len) < 0)
-  {
-    // BOOST_THROW_EXCEPTION(CcnxOperationException() << errmsg_info_str("decode ContentObject failed"));
-    _LOG_ERROR("<<< Decode content failed ");
-  }
-
-  string name;
-  for (int i = 0; i < info->content_comps->n - 1; i++)
-    {
-      char *comp;
-      size_t size;
-      name += "/";
-      ccn_name_comp_get(info->content_ccnb, info->content_comps, i, (const unsigned char **)&comp, &size);
-      string compStr(comp, size);
-      name += compStr;
-    }
-
-  cp->runCallback(name, pcontent, len);
-
-  return CCN_UPCALL_RESULT_OK;
-}
-
-int CcnxWrapper::sendInterestForString (const string &strInterest, const StringDataCallback &strDataCallback, int retry)
-{
-  DataClosurePass * pass = new DataClosurePass(STRING_FORM, retry, strDataCallback);
-  return sendInterest(strInterest, pass);
-}
-
-int CcnxWrapper::sendInterest (const string &strInterest, const RawDataCallback &rawDataCallback, int retry)
-{
-  RawDataClosurePass * pass = new RawDataClosurePass(RAW_DATA, retry, rawDataCallback);
-  return sendInterest(strInterest, pass);
-}
-
-int CcnxWrapper::sendInterest (const string &strInterest, void *dataPass)
-{
-  recursive_mutex::scoped_lock lock(m_mutex);
-  if (!m_running || !m_connected)
-    return -1;
-  
-  // std::cout << "Send interests for " << strInterest << std::endl;
-  ccn_charbuf *pname = ccn_charbuf_create();
-  ccn_closure *dataClosure = new ccn_closure;
-
-  ccn_name_from_uri (pname, strInterest.c_str());
-  dataClosure->data = dataPass;
-
-  dataClosure->p = &incomingData;
-  if (ccn_express_interest (m_handle, pname, dataClosure, NULL) < 0)
-  {
-    // BOOST_THROW_EXCEPTION(CcnxOperationException() << errmsg_info_str("express interest failed"));
-    _LOG_ERROR("<<< Express interest failed: " << strInterest);
-  }
-
-  _LOG_DEBUG("<<< Sending interest: " << strInterest);
-
-  ccn_charbuf_destroy (&pname);
-  return 0;
-}
-
-int CcnxWrapper::setInterestFilter (const string &prefix, const InterestCallback &interestCallback)
-{
-  recursive_mutex::scoped_lock lock(m_mutex);
-  if (!m_running || !m_connected)
-    return -1;
-
-  ccn_charbuf *pname = ccn_charbuf_create();
-  ccn_closure *interestClosure = new ccn_closure;
-
-  ccn_name_from_uri (pname, prefix.c_str());
-  interestClosure->data = new InterestCallback (interestCallback); // should be removed when closure is removed
-  interestClosure->p = &incomingInterest;
-  int ret = ccn_set_interest_filter (m_handle, pname, interestClosure);
-  if (ret < 0)
-    {
-      BOOST_THROW_EXCEPTION(CcnxOperationException() << errmsg_info_str("set interest filter failed") << errmsg_info_int (ret));
-    }
-
-  m_registeredInterests.insert(pair<std::string, InterestCallback>(prefix, interestCallback));
-  ccn_charbuf_destroy(&pname);
-
-  return 0;
-}
-
-void
-CcnxWrapper::clearInterestFilter (const std::string &prefix)
-{
-  recursive_mutex::scoped_lock lock(m_mutex);
-  if (!m_running || !m_connected)
-    return;
-
-  std::cout << "clearInterestFilter" << std::endl;
-  ccn_charbuf *pname = ccn_charbuf_create();
-
-  ccn_name_from_uri (pname, prefix.c_str());
-  int ret = ccn_set_interest_filter (m_handle, pname, 0);
-  if (ret < 0)
-    {
-      BOOST_THROW_EXCEPTION(CcnxOperationException() << errmsg_info_str("set interest filter failed") << errmsg_info_int (ret));
-    }
-
-  m_registeredInterests.erase(prefix);
-  ccn_charbuf_destroy(&pname);
-}
-
-string
-CcnxWrapper::getLocalPrefix ()
-{
-  struct ccn * tmp_handle = ccn_create ();
-  int res = ccn_connect (tmp_handle, NULL);
-  if (res < 0)
-    {
-      _LOG_ERROR ("connecting to ccnd failed");
-      return "";
-    }
-  
-  string retval = "";
-  
-  struct ccn_charbuf *templ = ccn_charbuf_create();
-  ccn_charbuf_append_tt(templ, CCN_DTAG_Interest, CCN_DTAG);
-  ccn_charbuf_append_tt(templ, CCN_DTAG_Name, CCN_DTAG);
-  ccn_charbuf_append_closer(templ); /* </Name> */
-  // XXX - use pubid if possible
-  ccn_charbuf_append_tt(templ, CCN_DTAG_MaxSuffixComponents, CCN_DTAG);
-  ccnb_append_number(templ, 1);
-  ccn_charbuf_append_closer(templ); /* </MaxSuffixComponents> */
-  ccnb_tagged_putf(templ, CCN_DTAG_Scope, "%d", 2);
-  ccn_charbuf_append_closer(templ); /* </Interest> */
-
-  struct ccn_charbuf *name = ccn_charbuf_create ();
-  res = ccn_name_from_uri (name, "/local/ndn/prefix");
-  if (res < 0) {
-    _LOG_ERROR ("Something wrong with `ccn_name_from_uri` call");
-  }
-  else
-    {
-      struct ccn_fetch *fetch = ccn_fetch_new (tmp_handle);
-      
-      struct ccn_fetch_stream *stream = ccn_fetch_open (fetch, name, "/local/ndn/prefix",
-                                                        NULL, 4, CCN_V_HIGHEST, 0);      
-      if (stream == NULL) {
-        _LOG_ERROR ("Cannot create ccn_fetch_stream");
-      }
-      else
-        {
-          ostringstream os;
-
-          int counter = 0;
-          char buf[256];
-          while (true) {
-            res = ccn_fetch_read (stream, buf, sizeof(buf));
-            
-            if (res == 0) {
-              break;
-            }
-            
-            if (res > 0) {
-              os << string(buf, res);
-            } else if (res == CCN_FETCH_READ_NONE) {
-              if (counter < 2)
-                {
-                  ccn_run(tmp_handle, 1000);
-                  counter ++;
-                }
-              else
-                {
-                  break;
-                }
-            } else if (res == CCN_FETCH_READ_END) {
-              break;
-            } else if (res == CCN_FETCH_READ_TIMEOUT) {
-              break;
-            } else {
-              _LOG_ERROR ("fatal error. should be reported");
-              break;
-            }
-          }
-          retval = os.str ();
-          stream = ccn_fetch_close(stream);
-        }
-      fetch = ccn_fetch_destroy(fetch);
-    }
-
-  ccn_charbuf_destroy (&name);
-
-  ccn_disconnect (tmp_handle);
-  ccn_destroy (&tmp_handle);
-  
-  return retval;
-}
-
-
-
-
-
-DataClosurePass::DataClosurePass (CallbackType type, int retry, const CcnxWrapper::StringDataCallback &strDataCallback): ClosurePass(type, retry), m_callback(NULL)
-{
-   m_callback = new CcnxWrapper::StringDataCallback (strDataCallback); 
-}
-
-DataClosurePass::~DataClosurePass () 
-{
-  delete m_callback;
-  m_callback = NULL;
-}
-
-void 
-DataClosurePass::runCallback(std::string name, const char *data, size_t len) 
-{
-  string content(data, len);
-  if (m_callback != NULL) {
-    (*m_callback)(name, content);
-  }
-}
-
-
-RawDataClosurePass::RawDataClosurePass (CallbackType type, int retry, const CcnxWrapper::RawDataCallback &rawDataCallback): ClosurePass(type, retry), m_callback(NULL)
-{
-   m_callback = new CcnxWrapper::RawDataCallback (rawDataCallback); 
-}
-
-RawDataClosurePass::~RawDataClosurePass () 
-{
-  delete m_callback;
-  m_callback = NULL;
-}
-
-void 
-RawDataClosurePass::runCallback(std::string name, const char *data, size_t len) 
-{
-  if (m_callback != NULL) {
-    (*m_callback)(name, data, len);
-  }
-}
-
-}
diff --git a/src/ccnx/sync-ccnx-wrapper.h b/src/ccnx/sync-ccnx-wrapper.h
deleted file mode 100644
index f0f8d8c..0000000
--- a/src/ccnx/sync-ccnx-wrapper.h
+++ /dev/null
@@ -1,198 +0,0 @@
-/* -*- Mode: C++; c-file-style: "gnu"; indent-tabs-mode:nil -*- */
-/*
- * Copyright (c) 2012 University of California, Los Angeles
- *
- * This program 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;
- *
- * 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
- *
- * Author: Zhenkai Zhu <zhenkai@cs.ucla.edu>
- *         Chaoyi Bian <bcy@pku.edu.cn>
- *	   Alexander Afanasyev <alexander.afanasyev@ucla.edu>
- */
-
-#ifndef SYNC_CCNX_WRAPPER_H
-#define SYNC_CCNX_WRAPPER_H
-
-extern "C" {
-#include <ccn/ccn.h>
-#include <ccn/charbuf.h>
-#include <ccn/keystore.h>
-#include <ccn/uri.h>
-#include <ccn/bloom.h>
-#include <ccn/signing.h>
-}
-
-#include <boost/exception/all.hpp>
-#include <boost/thread/recursive_mutex.hpp>
-#include <boost/thread/thread.hpp>
-#include <boost/function.hpp>
-#include <string>
-#include <sstream>
-#include <map>
-
-/**
- * \defgroup sync SYNC protocol
- *
- * Implementation of SYNC protocol
- */
-namespace Sync {
-
-struct CcnxOperationException : virtual boost::exception, virtual std::exception { };
-/**
- * \ingroup sync
- * @brief A wrapper for ccnx library; clients of this code do not need to deal
- * with ccnx library
- */
-class CcnxWrapper {
-public:
-  typedef boost::function<void (std::string, std::string)> StringDataCallback;
-  typedef boost::function<void (std::string, const char *buf, size_t len)> RawDataCallback;
-  typedef boost::function<void (std::string)> InterestCallback;
-
-public:
-
-#ifdef _DEBUG_WRAPPER_      
-  CcnxWrapper(char c='.');
-  char m_c;
-#else
-  CcnxWrapper();
-#endif
-
-  ~CcnxWrapper();
-
-  /**
-   * @brief send Interest; need to grab lock m_mutex first
-   *
-   * @param strInterest the Interest name
-   * @param dataCallback the callback function to deal with the returned data
-   * @return the return code of ccn_express_interest
-   */
-  int
-  sendInterestForString (const std::string &strInterest, const StringDataCallback &strDataCallback, int retry = 0);
-
-  int 
-  sendInterest (const std::string &strInterest, const RawDataCallback &rawDataCallback, int retry = 0);
-
-  /**
-   * @brief set Interest filter (specify what interest you want to receive)
-   *
-   * @param prefix the prefix of Interest
-   * @param interestCallback the callback function to deal with the returned data
-   * @return the return code of ccn_set_interest_filter
-   */
-  int
-  setInterestFilter (const std::string &prefix, const InterestCallback &interestCallback);
-
-  /**
-   * @brief clear Interest filter
-   * @param prefix the prefix of Interest
-   */
-  void
-  clearInterestFilter (const std::string &prefix);
-
-  /**
-   * @brief publish data and put it to local ccn content store; need to grab
-   * lock m_mutex first
-   *
-   * @param name the name for the data object
-   * @param dataBuffer the data to be published
-   * @param freshness the freshness time for the data object
-   * @return code generated by ccnx library calls, >0 if success
-   */
-  int
-  publishStringData (const std::string &name, const std::string &dataBuffer, int freshness);
-
-  int 
-  publishRawData (const std::string &name, const char *buf, size_t len, int freshness);
-
-  std::string
-  getLocalPrefix ();
-  
-protected:
-  void
-  connectCcnd();
-
-  /// @cond include_hidden 
-  void
-  createKeyLocator ();
-
-  void
-  initKeyStore ();
-
-  const ccn_pkey *
-  getPrivateKey ();
-
-  const unsigned char *
-  getPublicKeyDigest ();
-
-  ssize_t
-  getPublicKeyDigestLength ();
-
-  void
-  ccnLoop ();
-
-  int 
-  sendInterest (const std::string &strInterest, void *dataPass);
-  /// @endcond
-protected:
-  ccn* m_handle;
-  ccn_keystore *m_keyStore;
-  ccn_charbuf *m_keyLoactor;
-  // to lock, use "boost::recursive_mutex::scoped_lock scoped_lock(mutex);
-  boost::recursive_mutex m_mutex;
-  boost::thread m_thread;
-  bool m_running;
-  bool m_connected;
-  std::map<std::string, InterestCallback> m_registeredInterests;
-  // std::list< std::pair<std::string, InterestCallback> > m_registeredInterests;
-};
-
-typedef boost::shared_ptr<CcnxWrapper> CcnxWrapperPtr;
-
-enum CallbackType { STRING_FORM, RAW_DATA};
-
-class ClosurePass {
-public:
-  ClosurePass(CallbackType type, int retry): m_retry(retry), m_type(type) {}
-  int getRetry() {return m_retry;}
-  void decRetry() { m_retry--;}
-  CallbackType getCallbackType() {return m_type;}
-  virtual ~ClosurePass(){}
-  virtual void runCallback(std::string name, const char *data, size_t len) = 0;
-
-protected:
-  int m_retry;
-  CallbackType m_type;
-};
-
-class DataClosurePass: public ClosurePass {
-public:
-  DataClosurePass(CallbackType type, int retry, const CcnxWrapper::StringDataCallback &strDataCallback);
-  virtual ~DataClosurePass();
-  virtual void runCallback(std::string name, const char *, size_t len);
-private:
-  CcnxWrapper::StringDataCallback * m_callback;  
-};
-
-class RawDataClosurePass: public ClosurePass {
-public:
-  RawDataClosurePass(CallbackType type, int retry, const CcnxWrapper::RawDataCallback &RawDataCallback);
-  virtual ~RawDataClosurePass();
-  virtual void runCallback(std::string name, const char *, size_t len);
-private:
-  CcnxWrapper::RawDataCallback * m_callback;  
-};
-
-} // Sync
-
-#endif // SYNC_CCNX_WRAPPER_H
diff --git a/src/ccnx/sync-socket.cc b/src/ccnx/sync-socket.cc
new file mode 100644
index 0000000..48d4ad0
--- /dev/null
+++ b/src/ccnx/sync-socket.cc
@@ -0,0 +1,126 @@
+/* -*- Mode: C32++; c-file-style: "gnu"; indent-tabs-mode:nil -*- */
+/*
+ * Copyright (c) 2012 University of California, Los Angeles
+ *
+ * This program 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;
+ *
+ * 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
+ *
+ * Author: Yingdi Yu <yingdi@cs.ucla.edu>
+ */
+
+#include "sync-socket.h"
+
+using namespace std;
+using namespace ndn;
+
+namespace Sync {
+
+SyncSocket::SyncSocket (const string &syncPrefix, 
+                        Ptr<SyncPolicyManager> syncPolicyManager, 
+                        NewDataCallback dataCallback, 
+                        RemoveCallback rmCallback )
+  : m_newDataCallback(dataCallback)
+  , m_syncPolicyManager(syncPolicyManager)
+  , m_syncLogic (syncPrefix,
+                 syncPolicyManager,
+                 bind(&SyncSocket::passCallback, this, _1),
+                 rmCallback)
+{
+  Ptr<security::Keychain> keychain = Ptr<security::Keychain>(new security::Keychain(Ptr<security::IdentityManager>::Create(), m_syncPolicyManager, NULL));
+  m_handler = Ptr<Wrapper>(new Wrapper(keychain));
+}
+
+SyncSocket::~SyncSocket()
+{}
+
+bool 
+SyncSocket::publishData(const std::string &prefix, uint32_t session, const char *buf, size_t len, int freshness)
+{
+  uint32_t sequence = getNextSeq(prefix, session);
+  ostringstream contentNameWithSeqno;
+  contentNameWithSeqno << prefix << "/" << session << "/" << sequence;
+  
+  Name dataName(contentNameWithSeqno.str ());
+  Blob blob(buf, len);
+  Name signingIdentity = m_syncPolicyManager->inferSigningIdentity(dataName);
+  
+  m_handler->publishDataByIdentity (dataName, 
+                                    blob, 
+                                    signingIdentity, 
+                                    freshness);
+  
+  SeqNo s(session, sequence + 1);
+  m_sequenceLog[prefix] = s;
+  m_syncLogic.addLocalNames (prefix, session, sequence);
+  return true;
+}
+
+void 
+SyncSocket::fetchData(const string &prefix, const SeqNo &seq, const DataCallback& callback, int retry)
+{
+  ostringstream interestName;
+  interestName << prefix << "/" << seq.getSession() << "/" << seq.getSeq();
+  //std::cout << "Socket " << this << " Send Interest <" << interestName.str() << "> for raw data " << endl;
+  
+  
+  Ptr<ndn::Interest> interestPtr = Ptr<ndn::Interest>(new ndn::Interest(interestName.str()));
+  Ptr<Closure> closure = Ptr<Closure> (new Closure(callback,
+						   boost::bind(&SyncSocket::onChatDataTimeout,
+                                                               this,
+                                                               _1, 
+                                                               _2,
+                                                               retry),
+						   boost::bind(&SyncSocket::onChatDataUnverified,
+                                                               this,
+                                                               _1)));
+  m_handler->sendInterest(interestPtr, closure);
+}
+
+void
+SyncSocket::onChatDataTimeout(Ptr<Closure> closure, Ptr<ndn::Interest> interest, int retry)
+{
+  if(retry > 0)
+    {
+      Ptr<Closure> newClosure = Ptr<Closure>(new Closure(closure->m_dataCallback,
+                                                         boost::bind(&SyncSocket::onChatDataTimeout, 
+                                                                     this, 
+                                                                     _1, 
+                                                                     _2, 
+                                                                     retry - 1),
+                                                         closure->m_unverifiedCallback,
+                                                         closure->m_stepCount)
+                                             );
+      m_handler->sendInterest(interest, newClosure);
+    }
+}
+
+void
+SyncSocket::onChatDataUnverified(Ptr<Data> data)
+{}
+
+
+uint32_t
+SyncSocket::getNextSeq (const string &prefix, uint32_t session)
+{
+  SequenceLog::iterator i = m_sequenceLog.find (prefix);
+
+  if (i != m_sequenceLog.end ())
+    {
+      SeqNo s = i->second;
+      if (s.getSession() == session)
+        return s.getSeq();
+    }
+  return 0;
+}
+
+}//Sync
diff --git a/src/ccnx/sync-socket.h b/src/ccnx/sync-socket.h
new file mode 100644
index 0000000..a4530ba
--- /dev/null
+++ b/src/ccnx/sync-socket.h
@@ -0,0 +1,111 @@
+/* -*- Mode: C++; c-file-style: "gnu"; indent-tabs-mode:nil -*- */
+/*
+ * Copyright (c) 2012 University of California, Los Angeles
+ *
+ * This program 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;
+ *
+ * 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
+ *
+ * Author: Yingdi Yu <yingdi@cs.ucla.edu>
+ */
+
+#ifndef SYNC_SOCKET_H
+#define SYNC_SOCKET_H
+
+#include "sync-logic.h"
+#include <boost/function.hpp>
+#include <boost/unordered_map.hpp>
+#include "sync-seq-no.h"
+#include <ndn.cxx/wrapper/wrapper.h>
+#include <utility>
+#include <map>
+#include <vector>
+#include <sstream>
+
+namespace Sync {
+
+/**
+ * \ingroup sync
+ * @brief A simple interface to interact with client code
+ */
+class SyncSocket
+{
+public:
+  typedef boost::function< void (const std::vector<MissingDataInfo> &, SyncSocket * ) > NewDataCallback;
+  typedef boost::function< void ( const std::string &/*prefix*/ ) > RemoveCallback;
+  /**
+   * @brief the constructor for SyncAppSocket; the parameter syncPrefix
+   * should be passed to the constructor of m_syncAppWrapper; the other
+   * parameter should be passed to the constructor of m_fetcher; furthermore,
+   * the fetch function of m_fetcher should be a second paramter passed to
+   * the constructor of m_syncAppWrapper, so that m_syncAppWrapper can tell
+   * m_fetcher to fetch the actual app data after it learns the names
+   *
+   * @param syncPrefix the name prefix for Sync Interest
+   * @param dataCallback the callback to process data
+   */
+  SyncSocket (const std::string &syncPrefix, 
+              ndn::Ptr<SyncPolicyManager> syncPolicyManager,
+              NewDataCallback dataCallback, 
+              RemoveCallback rmCallback);
+
+  ~SyncSocket ();
+
+  bool 
+  publishData(const std::string &prefix, uint32_t session, const char *buf, size_t len, int freshness);
+
+  void 
+  remove (const std::string &prefix) 
+  { m_syncLogic.remove(prefix); }
+
+  void 
+  fetchData(const std::string &prefix, const SeqNo &seq, const ndn::DataCallback& callback, int retry = 0);
+
+  std::string 
+  getRootDigest() 
+  { return m_syncLogic.getRootDigest(); }
+
+  uint32_t
+  getNextSeq (const std::string &prefix, uint32_t session);
+
+  SyncLogic &
+  getLogic () 
+  { return m_syncLogic; }
+
+  // make this a static function so we don't have to create socket instance without
+  // knowing the local prefix. it's a wrong place for this function anyway
+  static std::string
+  GetLocalPrefix (); 
+  
+private:
+  void 
+  passCallback(const std::vector<MissingDataInfo> &v) 
+  { m_newDataCallback(v, this); }
+
+  void
+  onChatDataTimeout(ndn::Ptr<ndn::Closure> closure, ndn::Ptr<ndn::Interest> interest, int retry);
+
+  void
+  onChatDataUnverified(ndn::Ptr<ndn::Data> data);
+
+private:
+  typedef boost::unordered_map<std::string, SeqNo> SequenceLog;
+  NewDataCallback m_newDataCallback;
+  SequenceLog m_sequenceLog;
+  ndn::Ptr<SyncPolicyManager> m_syncPolicyManager;
+  ndn::Ptr<ndn::Wrapper> m_handler;
+  SyncLogic      m_syncLogic;
+};
+
+} // Sync
+
+#endif // SYNC_SOCKET_H