src: Small source reorganization

Change-Id: I442f3ad0392ef4220e6435fc48e6d69acbd02076
diff --git a/src/storage/sqlite-handle.cpp b/src/storage/sqlite-handle.cpp
new file mode 100644
index 0000000..02598a9
--- /dev/null
+++ b/src/storage/sqlite-handle.cpp
@@ -0,0 +1,841 @@
+/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
+/**
+ * Copyright (c) 2014,  Regents of the University of California.
+ *
+ * This file is part of NDN repo-ng (Next generation of NDN repository).
+ * See AUTHORS.md for complete list of repo-ng authors and contributors.
+ *
+ * repo-ng 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 3 of the License, or (at your option) any later version.
+ *
+ * repo-ng 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
+ * repo-ng, e.g., in COPYING.md file.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "config.hpp"
+#include "sqlite-handle.hpp"
+#include <boost/filesystem.hpp>
+
+namespace repo {
+
+SqliteHandle::SqliteHandle(const string& dbPath)
+  : StorageHandle(STORAGE_METHOD_SQLITE)
+{
+  if (dbPath.empty()) {
+    std::cerr << "Create db file in local location [" << dbPath << "]. " << std::endl
+              << "You can assign the path using -d option" << std::endl;
+    m_dbPath = string("ndn_repo.db");
+  }
+  else {
+    boost::filesystem::path fsPath(dbPath);
+    boost::filesystem::file_status fsPathStatus = boost::filesystem::status(fsPath);
+    if (!boost::filesystem::is_directory(fsPathStatus)) {
+      if (!boost::filesystem::create_directory(boost::filesystem::path(fsPath))) {
+        throw Error("Folder '" + dbPath + "' does not exists and cannot be created");
+      }
+    }
+
+    m_dbPath = dbPath + "/ndn_repo.db";
+  }
+  initializeRepo();
+}
+
+void
+SqliteHandle::initializeRepo()
+{
+  char* errMsg = 0;
+
+  int rc = sqlite3_open_v2(m_dbPath.c_str(), &m_db,
+                           SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE,
+#ifdef DISABLE_SQLITE3_FS_LOCKING
+                           "unix-dotfile"
+#else
+                           0
+#endif
+                           );
+
+  if (rc == SQLITE_OK) {
+    sqlite3_exec(m_db, "CREATE TABLE NDN_REPO ("
+                      "name BLOB PRIMARY KEY, "
+                      "data BLOB, "
+                      "parentName BLOB, "
+                      "nChildren INTEGER);\n"
+                      "CREATE INDEX NdnRepoParentName ON NDN_REPO (parentName);\n"
+                      "CREATE INDEX NdnRepoData ON NDN_REPO (data);\n"
+                 , 0, 0, &errMsg);
+    // Ignore errors (when database already exists, errors are expected)
+  }
+  else {
+    std::cerr << "Database file open failure rc:" << rc << std::endl;
+    throw Error("Database file open failure");
+  }
+
+  Name rootName;
+  string sql = string("SELECT * FROM NDN_REPO WHERE name = ?;");
+
+  sqlite3_stmt* queryStmt = 0;
+
+  rc = sqlite3_prepare_v2(m_db, sql.c_str(), -1, &queryStmt, 0);
+  if (rc == SQLITE_OK) {
+    if (sqlite3_bind_blob(queryStmt, 1, rootName.wireEncode().wire(),
+                          rootName.wireEncode().size(), 0) == SQLITE_OK) {
+      rc = sqlite3_step(queryStmt);
+      if (rc == SQLITE_ROW) {
+        std::cerr << "root has been created" << std::endl;
+      }
+      else if (rc == SQLITE_DONE) {
+        sqlite3_stmt* p2Stmt = 0;
+        sql = string("INSERT INTO NDN_REPO (name, data, parentName, nChildren) "
+                     " VALUES (?,    ?,    ?,     ?);");
+        rc = sqlite3_prepare_v2(m_db, sql.c_str(), -1, &p2Stmt, 0);
+        if (rc == SQLITE_OK) {
+          if (sqlite3_bind_blob(p2Stmt, 1, rootName.wireEncode().wire(),
+                                rootName.wireEncode().size(), 0) == SQLITE_OK &&
+              sqlite3_bind_null(p2Stmt, 2) == SQLITE_OK &&
+              sqlite3_bind_null(p2Stmt, 3) == SQLITE_OK &&
+              sqlite3_bind_int(p2Stmt, 4, 0) == SQLITE_OK) {
+            rc = sqlite3_step(p2Stmt);;
+            if (rc != SQLITE_ROW && rc != SQLITE_DONE) {
+              std::cerr << "Root name insert failure rc:" << rc << std::endl;
+              sqlite3_finalize(p2Stmt);
+              throw Error("Root name insert failure");
+            }
+          }
+          else {
+            std::cerr << "bind blob failure rc:" << rc << std::endl;
+            sqlite3_finalize(p2Stmt);
+            throw Error("bind blob failure");
+          }
+        }
+        else {
+          std::cerr << "p2Stmt prepared rc:" << rc << std::endl;
+          sqlite3_finalize(p2Stmt);
+          throw Error("p2Stmt prepared");
+        }
+        sqlite3_finalize(p2Stmt);
+      }
+      else {
+        std::cerr << "Database query failure rc:" << rc << std::endl;
+        sqlite3_finalize(queryStmt);
+        throw Error("Database query failure");
+      }
+    }
+    sqlite3_finalize(queryStmt);
+  }
+  sqlite3_exec(m_db, "PRAGMA synchronous = OFF", 0, 0, &errMsg);
+  sqlite3_exec(m_db, "PRAGMA journal_mode = WAL", 0, 0, &errMsg);
+}
+
+SqliteHandle::~SqliteHandle()
+{
+  sqlite3_close(m_db);
+}
+
+
+//Temporarily assigned the datatype of every component. needs to be further discussed
+
+bool
+SqliteHandle::insertData(const Data& data)
+{
+  Name name = data.getName();
+
+  if (name.empty()) {
+    std::cerr << "name is empty" << std::endl;
+    return false;
+  }
+
+  int rc = 0;
+
+  string updateSql2 = string("UPDATE NDN_REPO SET data = ? WHERE name = ?;");
+  //std::cerr << "update" << std::endl;
+  sqlite3_stmt* update2Stmt = 0;
+  if (sqlite3_prepare_v2(m_db, updateSql2.c_str(), -1, &update2Stmt, 0) != SQLITE_OK) {
+    sqlite3_finalize(update2Stmt);
+    std::cerr << "update sql2 not prepared" << std::endl;
+    throw Error("update sql2 not prepared");
+  }
+  if (sqlite3_bind_blob(update2Stmt, 1,
+                        data.wireEncode().wire(),
+                        data.wireEncode().size(), 0) == SQLITE_OK &&
+      sqlite3_bind_blob(update2Stmt, 2,
+                        name.wireEncode().wire(),
+                        name.wireEncode().size(), 0) == SQLITE_OK) {
+    rc = sqlite3_step(update2Stmt);
+    sqlite3_finalize(update2Stmt);
+    if (rc != SQLITE_DONE) {
+      return false;
+    }
+    //what error??
+    //std::cerr << "update rc:" << rc << std::endl;
+    /// \todo Do something with rc
+  }
+  int changeCount = sqlite3_changes(m_db);
+  //std::cerr << "changeCount: " << changeCount << std::endl;
+  if (changeCount > 0) {
+    return true;
+  }
+
+  sqlite3_stmt* insertStmt = 0;
+  sqlite3_stmt* updateStmt = 0;
+  string insertSql = string("INSERT INTO NDN_REPO (name, data, parentName, nChildren) "
+                            "VALUES (?, ?, ?, ?)");
+  string updateSql = string("UPDATE NDN_REPO SET nChildren = nChildren + 1 WHERE name = ?");
+
+  Name rootName;
+
+
+  if (sqlite3_prepare_v2(m_db, insertSql.c_str(), -1, &insertStmt, 0) != SQLITE_OK) {
+    sqlite3_finalize(insertStmt);
+    std::cerr << "insert sql not prepared" << std::endl;
+  }
+  if (sqlite3_prepare_v2(m_db, updateSql.c_str(), -1, &updateStmt, 0) != SQLITE_OK) {
+    sqlite3_finalize(updateStmt);
+    std::cerr << "update sql not prepared" << std::endl;
+    throw Error("update sql not prepared");
+  }
+
+  //Insert and read the prefix
+  Name parentName = name;
+  Name grandName;
+  do {
+    parentName = parentName.getPrefix(-1);
+    if (!hasName(parentName)) {
+      grandName = parentName.getPrefix(-1);
+      if (sqlite3_bind_blob(insertStmt, 1,
+                            parentName.wireEncode().wire(),
+                            parentName.wireEncode().size(), 0) == SQLITE_OK &&
+          sqlite3_bind_null(insertStmt, 2) == SQLITE_OK &&
+          sqlite3_bind_blob(insertStmt, 3,
+                            grandName.wireEncode().wire(),
+                            grandName.wireEncode().size(), 0) == SQLITE_OK &&
+          sqlite3_bind_int(insertStmt, 4, 1) == SQLITE_OK) {
+        rc = sqlite3_step(insertStmt);
+        if (rc == SQLITE_CONSTRAINT) {
+          std::cerr << "Insert parent prefix failed" << std::endl;
+          sqlite3_finalize(insertStmt);
+          throw Error("Insert parent prefix failed");
+        }
+        sqlite3_reset(insertStmt);
+      }
+    }
+    else {
+      break;
+    }
+  } while (!parentName.empty());
+
+  //The existed parent nChildren + 1
+
+  if (sqlite3_bind_blob(updateStmt, 1, parentName.wireEncode().wire(),
+                        parentName.wireEncode().size(), 0) == SQLITE_OK) {
+    rc = sqlite3_step(updateStmt);
+    if (rc != SQLITE_ROW && rc != SQLITE_DONE) {
+      std::cerr << "update error rc:" << rc << std::endl;
+      sqlite3_finalize(updateStmt);
+      sqlite3_finalize(insertStmt);
+      throw Error("update error");
+    }
+    sqlite3_reset(updateStmt);
+  }
+
+  //Insert the name and the data, if this data name exists update, else insert data
+
+  parentName = name.getPrefix(-1);
+  sqlite3_reset(insertStmt);
+  if (sqlite3_bind_blob(insertStmt, 1,
+                        name.wireEncode().wire(),
+                        name.wireEncode().size(), 0) == SQLITE_OK &&
+      sqlite3_bind_blob(insertStmt, 2,
+                        data.wireEncode().wire(),
+                        data.wireEncode().size(), 0) == SQLITE_OK &&
+      sqlite3_bind_blob(insertStmt, 3,
+                        parentName.wireEncode().wire(),
+                        parentName.wireEncode().size(), 0) == SQLITE_OK &&
+      sqlite3_bind_int(insertStmt, 4, 0) == SQLITE_OK) {
+    rc = sqlite3_step(insertStmt);
+    //std::cerr << "insert rc:" << rc << std::endl;
+    //std::cerr << "insert the data: " << data.wireEncode().wire() << std::endl;
+    if (rc == SQLITE_CONSTRAINT) {
+      std::cerr << "The name of the data has existed!" << std::endl;
+      sqlite3_finalize(insertStmt);
+      return false;
+    }
+  }
+
+  sqlite3_finalize(updateStmt);
+  sqlite3_finalize(insertStmt);
+  return true;
+}
+
+bool
+SqliteHandle::deleteData(const Name& name)
+{
+  sqlite3_stmt* queryStmt = 0;
+  sqlite3_stmt* deleteStmt = 0;
+  sqlite3_stmt* updateStmt = 0;
+  sqlite3_stmt* update2Stmt = 0;
+
+  string querySql = string("SELECT * from NDN_REPO where name = ?;");
+  string deleteSql = string("DELETE from NDN_REPO where name = ?;");
+
+  string updateSql = string("UPDATE NDN_REPO SET nChildren = nChildren - 1 WHERE name = ?;");
+  string updateSql2 = string("UPDATE NDN_REPO SET data = NULL WHERE name = ?;");
+
+  int rc = sqlite3_prepare_v2(m_db, querySql.c_str(), -1, &queryStmt, 0);
+  Name tmpName = name;
+  int nChildren = -1;
+  if (sqlite3_prepare_v2(m_db, deleteSql.c_str(), -1, &deleteStmt, 0) != SQLITE_OK) {
+    sqlite3_finalize(deleteStmt);
+    std::cerr << "delete statement prepared failed" << std::endl;
+    throw Error("delete statement prepared failed");
+  }
+  if (sqlite3_prepare_v2(m_db, updateSql.c_str(), -1, &updateStmt, 0) != SQLITE_OK) {
+    sqlite3_finalize(updateStmt);
+    std::cerr << "delete update prepared failed" << std::endl;
+    throw Error("delete update prepared failed");
+  }
+  if (rc == SQLITE_OK) {
+    if (sqlite3_bind_blob(queryStmt, 1,
+                          tmpName.wireEncode().wire(),
+                          tmpName.wireEncode().size(), 0) == SQLITE_OK) {
+      rc = sqlite3_step(queryStmt);
+      if (rc == SQLITE_ROW) {
+        nChildren = sqlite3_column_int(queryStmt, 3);
+      }
+      else {
+        std::cerr << "Database query no such name or failure rc:" << rc << std::endl;
+        sqlite3_finalize(queryStmt);
+        return false;
+      }
+    }
+    if (nChildren > 0) {
+      //update internal node, so just update and return
+      if (sqlite3_prepare_v2(m_db, updateSql2.c_str(), -1, &update2Stmt, 0) != SQLITE_OK) {
+        sqlite3_finalize(update2Stmt);
+        std::cerr << "delete update prepared failed" << std::endl;
+        throw Error("delete update prepared failed");
+      }
+      if (sqlite3_bind_blob(update2Stmt, 1,
+                            tmpName.wireEncode().wire(),
+                            tmpName.wireEncode().size(), 0) == SQLITE_OK) {
+        rc = sqlite3_step(update2Stmt);
+        std::cerr << "deleteData update" << std::endl;
+      }
+      else {
+        std::cerr << "delete bind error" << std::endl;
+        sqlite3_finalize(update2Stmt);
+        throw Error("delete bind error");
+      }
+      return true;
+    }
+    else {
+      //Delete the leaf node
+      if (sqlite3_bind_blob(deleteStmt, 1,
+                            tmpName.wireEncode().wire(),
+                            tmpName.wireEncode().size(), 0) == SQLITE_OK) {
+        rc = sqlite3_step(deleteStmt);
+        if (rc != SQLITE_DONE && rc !=SQLITE_ROW) {
+          std::cerr << "leaf node delete error rc:" << rc << std::endl;
+          sqlite3_finalize(deleteStmt);
+          throw Error("leaf node delete error");
+        }
+      }
+      else {
+        std::cerr << "delete bind error" << std::endl;
+        sqlite3_finalize(deleteStmt);
+        throw Error("delete bind error");
+      }
+      sqlite3_reset(deleteStmt);
+    }
+    queryStmt = 0;
+    rc = sqlite3_prepare_v2(m_db, querySql.c_str(), -1, &queryStmt, 0);
+    if (rc != SQLITE_OK) {
+      std::cerr << "prepare error" << std::endl;
+      sqlite3_finalize(queryStmt);
+      throw Error("prepare error");
+    }
+    //read prefix if nChildren is 0 and data is 0
+    int dataSize = 0;
+    do {
+      tmpName = tmpName.getPrefix(-1);
+      if (sqlite3_bind_blob(queryStmt, 1,
+                            tmpName.wireEncode().wire(),
+                            tmpName.wireEncode().size(), 0) == SQLITE_OK) {
+        rc = sqlite3_step(queryStmt);
+        if (rc == SQLITE_ROW) {
+          nChildren = sqlite3_column_int(queryStmt, 3);
+          dataSize = sqlite3_column_bytes(queryStmt, 1);
+        }
+        else {
+          std::cerr << "Database query no such name or failure rc:" << rc << std::endl;
+          sqlite3_finalize(queryStmt);
+          return false;
+        }
+        if (nChildren == 1 && !tmpName.empty() && dataSize == 0) {
+          //Delete this internal node
+          if (sqlite3_bind_blob(deleteStmt, 1,
+                                tmpName.wireEncode().wire(),
+                                tmpName.wireEncode().size(), 0) == SQLITE_OK) {
+            rc = sqlite3_step(deleteStmt);
+            if (rc != SQLITE_DONE && rc !=SQLITE_ROW) {
+              std::cerr << "internal node delete error rc:" << rc << std::endl;
+              sqlite3_finalize(deleteStmt);
+              throw Error("internal node delete error");
+            }
+          }
+          else {
+            std::cerr << "delete bind error" << std::endl;
+            sqlite3_finalize(deleteStmt);
+            throw Error("delete bind error");
+          }
+          sqlite3_reset(deleteStmt);
+        }
+        else {
+          //nChildren - 1
+          if (sqlite3_bind_blob(updateStmt, 1,
+                                tmpName.wireEncode().wire(),
+                                tmpName.wireEncode().size(), 0) == SQLITE_OK) {
+            rc = sqlite3_step(updateStmt);
+            if (rc != SQLITE_DONE && rc !=SQLITE_ROW) {
+              std::cerr << "internal node nChildren update error rc:" << rc << std::endl;
+              sqlite3_finalize(updateStmt);
+              throw Error("internal node nChildren update error");
+            }
+          }
+          else {
+            std::cerr << "update bind error" << std::endl;
+            sqlite3_finalize(updateStmt);
+            throw Error("update bind error");
+          }
+          sqlite3_reset(updateStmt);
+          break;
+        }
+      }
+      else {
+        std::cerr << "query bind error" << std::endl;
+        sqlite3_finalize(queryStmt);
+        throw Error("query bind error");
+      }
+      sqlite3_reset(queryStmt);
+    } while (!tmpName.empty());
+
+  }
+  else {
+    std::cerr << "query prepared failure rc:" << rc << std::endl;
+    sqlite3_finalize(queryStmt);
+    throw Error("query prepared failure");
+  }
+  return true;
+}
+
+bool
+SqliteHandle::readData(const Interest& interest, Data& data)
+{
+  vector<Name> names;
+  Name resultName;
+  if (!interest.hasSelectors()) {
+    return readDataPlain(interest.getName(), data);
+  }
+  else {
+    if (readNameSelector(interest, names)) {
+      if (!filterNameChild(interest.getName(), interest.getChildSelector(), names, resultName)) {
+        return false;
+      }
+    }
+    return readData(resultName, data);
+  }
+}
+
+// This function is the first version of data read following longest prefix match.
+// It will return the leftmost data
+bool
+SqliteHandle::readDataPlain(const Name& name, Data& data)
+{
+  vector<Name> names;
+  Name resultName;
+  readDataName(name, names);
+  filterNameChild(name, 0, names, resultName);
+  if (!resultName.empty()) {
+    return readData(resultName, data);
+  }
+  else
+  {
+    return false;
+  }
+}
+
+// retrieve all the leaf nodes of a subtree
+bool
+SqliteHandle::readDataName(const Name& name, vector<Name>& names) const
+{
+  if (name.empty()) {
+    std::cerr << "The name is empty" << std::endl;
+    return false;
+  }
+  Name tmpName = name;
+  //This queue is for internal node;
+  queue<Name> internalNames;
+
+  // Step 1. Check if the requested name corresponds to a leaf (data is not NULL)
+  string sql = string("SELECT * FROM NDN_REPO WHERE name = ? AND data IS NOT NULL;");
+  sqlite3_stmt* queryStmt = 0;
+  int rc = sqlite3_prepare_v2(m_db, sql.c_str(), -1, &queryStmt, 0);
+  if (rc != SQLITE_OK)
+    throw Error("prepare error");
+
+  if (sqlite3_bind_blob(queryStmt, 1,
+                        tmpName.wireEncode().wire(),
+                        tmpName.wireEncode().size(), 0) == SQLITE_OK) {
+    rc = sqlite3_step(queryStmt);
+    if (rc == SQLITE_ROW) {
+      int nChildren = sqlite3_column_int(queryStmt, 3);
+      Name elementName;
+      elementName.wireDecode(Block(sqlite3_column_blob(queryStmt, 0),
+                                   sqlite3_column_bytes(queryStmt, 0)));
+      names.push_back(elementName);
+      if (nChildren == 0) {
+        sqlite3_finalize(queryStmt);
+        return true;
+      }
+    }
+    else if (rc == SQLITE_DONE) {
+      // ignore
+    }
+    else {
+      std::cerr << "read error rc:" << rc << std::endl;
+      sqlite3_finalize(queryStmt);
+      throw Error("read error");
+    }
+  }
+  sqlite3_finalize(queryStmt);
+
+
+  // Step 2. Recursively find all data packets with the specified prefix
+  string psql = string("SELECT * FROM NDN_REPO WHERE parentName = ?;");
+  sqlite3_stmt* queryParentStmt = 0;
+  rc = sqlite3_prepare_v2(m_db, psql.c_str(), -1, &queryParentStmt, 0);
+  if (rc != SQLITE_OK)
+    throw Error("prepare error");
+
+  internalNames.push(tmpName);
+  while (!internalNames.empty()) {
+    tmpName = internalNames.front();
+    internalNames.pop();
+    if (sqlite3_bind_blob(queryParentStmt, 1,
+                          tmpName.wireEncode().wire(),
+                          tmpName.wireEncode().size(), 0) == SQLITE_OK) {
+      while (true) {
+        rc = sqlite3_step(queryParentStmt);
+        if (rc == SQLITE_ROW) {
+          Name elementName;
+          elementName.wireDecode(Block(sqlite3_column_blob(queryParentStmt, 0),
+                                       sqlite3_column_bytes(queryParentStmt, 0)));
+          int nChildren = sqlite3_column_int(queryParentStmt, 3);
+          if (nChildren > 0) {
+            internalNames.push(elementName);
+          }
+          if (sqlite3_column_type(queryParentStmt, 1) != SQLITE_NULL) {
+            names.push_back(elementName);
+          }
+        }
+        else if (rc == SQLITE_DONE) {
+          break;
+        }
+        else {
+          std::cerr << "read error rc:" << rc << std::endl;
+          sqlite3_finalize(queryParentStmt);
+          throw Error("read error");
+        }
+      }
+      sqlite3_reset(queryParentStmt);
+    }
+    else {
+      std::cerr << "bind error" << std::endl;
+      sqlite3_finalize(queryParentStmt);
+      throw Error("bind error");
+    }
+  }
+  sqlite3_finalize(queryParentStmt);
+  return true;
+}
+
+bool
+SqliteHandle::readNameSelector(const Interest& interest, vector<Name>& names) const
+{
+  if (interest.getName().empty()) {
+    std::cerr << "The name of interest is empty" << std::endl;
+    return false;
+  }
+  Name tmpName = interest.getName();
+  //This queue is for internal node;
+  queue<Name> internalNames;
+
+  // Step 1. Check if the requested Data corresponds to a leaf (data is not NULL)
+  sqlite3_stmt* queryStmt = 0;
+  string sql = string("SELECT * FROM NDN_REPO WHERE name = ? AND data IS NOT NULL;");
+  int rc = sqlite3_prepare_v2(m_db, sql.c_str(), -1, &queryStmt, 0);
+  if (rc != SQLITE_OK)
+    throw Error("prepare error");
+
+  if (sqlite3_bind_blob(queryStmt, 1,
+                        tmpName.wireEncode().wire(),
+                        tmpName.wireEncode().size(), 0) == SQLITE_OK) {
+    rc = sqlite3_step(queryStmt);
+    if (rc == SQLITE_ROW) {
+      Data elementData;
+      elementData.wireDecode(Block(sqlite3_column_blob(queryStmt, 1),
+                                   sqlite3_column_bytes(queryStmt, 1)));
+      if (interest.matchesData(elementData)) {
+        names.push_back(elementData.getName());
+      }
+
+      int nChildren = sqlite3_column_int(queryStmt, 3);
+      if (nChildren == 0) {
+        sqlite3_finalize(queryStmt);
+        return true;
+      }
+    }
+    else if (rc == SQLITE_DONE) {
+      // ignore
+    }
+    else {
+      std::cerr << "read error rc:" << rc << std::endl;
+      sqlite3_finalize(queryStmt);
+      throw Error("read error");
+    }
+  }
+  sqlite3_finalize(queryStmt);
+
+  // Step 2. Recursively find all data packets that match the Interest
+  internalNames.push(tmpName);
+  sqlite3_stmt* queryParentStmt = 0;
+  string psql = string("SELECT * FROM NDN_REPO WHERE parentName = ?;");
+  rc = sqlite3_prepare_v2(m_db, psql.c_str(), -1, &queryParentStmt, 0);
+  if (rc != SQLITE_OK)
+    throw Error("prepare error");
+
+  while (!internalNames.empty()) {
+    tmpName = internalNames.front();
+    internalNames.pop();
+    if (sqlite3_bind_blob(queryParentStmt, 1,
+                          tmpName.wireEncode().wire(),
+                          tmpName.wireEncode().size(), 0) == SQLITE_OK) {
+      while (true) {
+        rc = sqlite3_step(queryParentStmt);
+        if (rc == SQLITE_ROW) {
+          if (sqlite3_column_type(queryParentStmt, 1) != SQLITE_NULL) {
+            Data elementData;
+            elementData.wireDecode(Block(sqlite3_column_blob(queryParentStmt, 1),
+                                         sqlite3_column_bytes(queryParentStmt, 1)));
+            if (interest.matchesData(elementData)) {
+              names.push_back(elementData.getName());
+            }
+          }
+
+          Name elementName;
+          elementName.wireDecode(Block(sqlite3_column_blob(queryParentStmt, 0),
+                                       sqlite3_column_bytes(queryParentStmt, 0)));
+
+          int nChildren = sqlite3_column_int(queryParentStmt, 3);
+          if (nChildren > 0) {
+            internalNames.push(elementName);
+          }
+        }
+        else if (rc == SQLITE_DONE) {
+          break;
+        }
+        else {
+          std::cerr << "read error rc:" << rc << std::endl;
+          sqlite3_finalize(queryParentStmt);
+          throw Error("read error");
+        }
+      }
+      sqlite3_reset(queryParentStmt);
+    }
+    else {
+      std::cerr << "bind error" << std::endl;
+      sqlite3_finalize(queryParentStmt);
+      throw Error("bind error");
+    }
+  }
+  sqlite3_finalize(queryParentStmt);
+  return true;
+}
+
+bool
+SqliteHandle::filterNameChild(const Name& name, int childSelector,
+                              const vector<Name>& names, Name& resultName)
+{
+  if (childSelector == 0) {
+    if (!names.empty()) {
+      resultName = *std::min_element(names.begin(), names.end());
+    }
+    else {
+      return false;
+    }
+  }
+  else if (childSelector == 1) {
+    if (!names.empty()) {
+      resultName = *std::max_element(names.begin(), names.end());
+    }
+    else {
+      return false;
+    }
+  }
+  else {
+    return false;
+  }
+  return true;
+}
+
+bool
+SqliteHandle::readNameAny(const Name& name, const Selectors& selectors, vector<Name>& names)
+{
+  if (selectors.empty()) {
+    if (hasName(name)) {
+      names.push_back(name);
+    }
+    return true;
+  }
+  else {
+    Interest interest(name);
+    interest.setSelectors(selectors);
+    readNameSelector(interest, names);
+    if (selectors.getChildSelector() >= 0) {
+      Name resultName;
+      if (!filterNameChild(name, selectors.getChildSelector(), names, resultName))
+        return false;
+      names.clear();
+      names.push_back(resultName);
+      return true;
+    }
+    else {
+      return true;
+    }
+  }
+}
+
+bool
+SqliteHandle::readData(const Name& name, Data& data)
+{
+  sqlite3_stmt* queryStmt = 0;
+  string sql = string("SELECT * FROM NDN_REPO WHERE name = ? AND data IS NOT NULL;");
+  int rc = sqlite3_prepare_v2(m_db, sql.c_str(), -1, &queryStmt, 0);
+  if (rc == SQLITE_OK) {
+    if (sqlite3_bind_blob(queryStmt, 1,
+                          name.wireEncode().wire(),
+                          name.wireEncode().size(), 0) == SQLITE_OK) {
+      rc = sqlite3_step(queryStmt);
+      if (rc == SQLITE_ROW) {
+        data.wireDecode(Block(sqlite3_column_blob(queryStmt, 1),
+                              sqlite3_column_bytes(queryStmt, 1)));
+        sqlite3_finalize(queryStmt);
+        return true;
+      }
+      else if (rc == SQLITE_DONE) {
+        return false;
+      }
+      else {
+        std::cerr << "Database query failure rc:" << rc << std::endl;
+        sqlite3_finalize(queryStmt);
+        throw Error("Database query failure");
+      }
+    }
+    sqlite3_finalize(queryStmt);
+  }
+  return true;
+}
+
+
+//This is the exact name query in database.
+bool
+SqliteHandle::hasName(const Name& name)
+{
+  sqlite3_stmt* queryStmt = 0;
+  string sql = string("select * from NDN_REPO where name = ?;");
+  int rc = sqlite3_prepare_v2(m_db, sql.c_str(), -1, &queryStmt, 0);
+  if (rc == SQLITE_OK) {
+    if (sqlite3_bind_blob(queryStmt, 1,
+                          name.wireEncode().wire(),
+                          name.wireEncode().size(), 0) == SQLITE_OK) {
+      rc = sqlite3_step(queryStmt);
+      if (rc == SQLITE_ROW) {
+        sqlite3_finalize(queryStmt);
+        return true;
+      }
+      else if (rc == SQLITE_DONE) {
+        sqlite3_finalize(queryStmt);
+        return false;
+      }
+      else {
+        std::cerr << "Database query failure rc:" << rc << std::endl;
+        sqlite3_finalize(queryStmt);
+        return false;
+      }
+    }
+    sqlite3_finalize(queryStmt);
+  }
+  return true;
+}
+
+//This is the exact parent name query in database.
+bool
+SqliteHandle::hasParentName(const Name& parentName) const
+{
+  sqlite3_stmt* queryStmt = 0;
+  string sql = string("SELECT * FROM NDN_REPO WHERE parentName = ?;");
+  int rc = sqlite3_prepare_v2(m_db, sql.c_str(), -1, &queryStmt, 0);
+  if (rc == SQLITE_OK) {
+    if (sqlite3_bind_blob(queryStmt, 1,
+                          parentName.wireEncode().wire(),
+                          parentName.wireEncode().size(), 0) == SQLITE_OK) {
+      rc = sqlite3_step(queryStmt);
+      if (rc == SQLITE_ROW) {
+        sqlite3_finalize(queryStmt);
+        return true;
+      }
+      else if (rc == SQLITE_DONE) {
+        sqlite3_finalize(queryStmt);
+        return false;
+      }
+      else {
+        std::cerr << "Database query failure rc:" << rc << std::endl;
+        sqlite3_finalize(queryStmt);
+        return false;
+      }
+    }
+    sqlite3_finalize(queryStmt);
+  }
+  return true;
+}
+
+size_t
+SqliteHandle::size()
+{
+  sqlite3_stmt* queryStmt = 0;
+  string sql("SELECT count(*) FROM NDN_REPO WHERE data IS NOT NULL");
+  int rc = sqlite3_prepare_v2(m_db, sql.c_str(), -1, &queryStmt, 0);
+  if (rc != SQLITE_OK)
+    {
+      std::cerr << "Database query failure rc:" << rc << std::endl;
+      sqlite3_finalize(queryStmt);
+      throw Error("Database query failure");
+    }
+
+  rc = sqlite3_step(queryStmt);
+  if (rc != SQLITE_ROW)
+    {
+      std::cerr << "Database query failure rc:" << rc << std::endl;
+      sqlite3_finalize(queryStmt);
+      throw Error("Database query failure");
+    }
+
+  size_t nDatas = static_cast<size_t>(sqlite3_column_int64(queryStmt, 0));
+  return nDatas;
+}
+
+} //namespace repo
diff --git a/src/storage/sqlite-handle.hpp b/src/storage/sqlite-handle.hpp
new file mode 100644
index 0000000..a0fbb1c
--- /dev/null
+++ b/src/storage/sqlite-handle.hpp
@@ -0,0 +1,144 @@
+/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
+/**
+ * Copyright (c) 2014,  Regents of the University of California.
+ *
+ * This file is part of NDN repo-ng (Next generation of NDN repository).
+ * See AUTHORS.md for complete list of repo-ng authors and contributors.
+ *
+ * repo-ng 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 3 of the License, or (at your option) any later version.
+ *
+ * repo-ng 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
+ * repo-ng, e.g., in COPYING.md file.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef REPO_STORAGE_SQLITE_HANDLE_HPP
+#define REPO_STORAGE_SQLITE_HANDLE_HPP
+
+#include "storage-handle.hpp"
+
+#include <string>
+#include <iostream>
+#include <sqlite3.h>
+#include <stdlib.h>
+#include <vector>
+#include <queue>
+#include <algorithm>
+
+namespace repo {
+
+using std::queue;
+
+class SqliteHandle : public StorageHandle
+{
+public:
+  class Error : public StorageHandle::Error
+  {
+  public:
+    explicit
+    Error(const std::string& what)
+      : StorageHandle::Error(what)
+    {
+    }
+  };
+
+  SqliteHandle();
+
+  explicit
+  SqliteHandle(const string& dbPath);
+
+  virtual
+  ~SqliteHandle();
+
+
+  // from StorageHandle
+
+  virtual bool
+  insertData(const Data& data);
+
+  virtual bool
+  deleteData(const Name& name);
+
+  virtual bool
+  readData(const Interest& interest, Data& data);
+
+  virtual bool
+  hasName(const Name& name);
+
+  virtual bool
+  readNameAny(const Name& name, const Selectors& selectors, vector<Name>& names);
+
+  virtual size_t
+  size();
+
+private:
+  void
+  initializeRepo();
+
+  /**
+  * @brief find data with the exact name matched
+  * @param[out] data Data matching Interest.
+  * @return if no data or something is wrong, return false
+  */
+  bool
+  readData(const Name& name, Data& data);
+
+  /**
+  * @brief check whether there is one row with this parentName = parentName in database
+  * @return if no data or something is wrong, return false.
+  */
+  bool
+  hasParentName(const Name& parentName) const;
+
+  /**
+  * @brief This function is for no selector, it will reply the leftmost data
+  * @param[out] data Data matching Interest.
+  * @return if no data or something is wrong, return false.
+  */
+  bool
+  readDataPlain(const Name& name, Data& data);
+
+  /**
+  * @brief  read data with this prefix or name
+  * @param name indicates name or prefix of interest
+  * @param[out] names is vector to contain the result of this function.
+  * @return success return true, error return false
+  */
+  bool
+  readDataName(const Name& name, vector<Name>& names) const;
+
+  /**
+  * @brief  read data with this prefix or name and selectors including  MinSuffixComponents,
+  * MaxSuffixComponents, PublisherPublicKeyLocator, and Exclude.
+  * This method does not consider ChildSelector and MustBeFresh.
+  *
+  * @param name indicates name or prefix of interest
+  * @param[out] names is vector to contain the result of this function.
+  * @return success return true, error return false
+  */
+  bool
+  readNameSelector(const Interest& interest, vector<Name>& names) const;
+
+  /**
+  * @brief ChildSelector filter
+  * @param names list of candidate names for ChildSelector filter
+  * @param[out] resultName is the result of selected name
+  * @return success return true, error return false
+  */
+  bool
+  filterNameChild(const Name& name, int childSelector,
+                  const vector<Name>& names, Name& resultName);
+
+private:
+  sqlite3* m_db;
+  string m_dbPath;
+};
+
+} // namespace repo
+
+#endif // REPO_STORAGE_SQLITE_HANDLE_HPP
diff --git a/src/storage/storage-handle.hpp b/src/storage/storage-handle.hpp
new file mode 100644
index 0000000..b75de2c
--- /dev/null
+++ b/src/storage/storage-handle.hpp
@@ -0,0 +1,126 @@
+/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
+/**
+ * Copyright (c) 2014,  Regents of the University of California.
+ *
+ * This file is part of NDN repo-ng (Next generation of NDN repository).
+ * See AUTHORS.md for complete list of repo-ng authors and contributors.
+ *
+ * repo-ng 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 3 of the License, or (at your option) any later version.
+ *
+ * repo-ng 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
+ * repo-ng, e.g., in COPYING.md file.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef REPO_STORAGE_STORAGE_HANDLE_HPP
+#define REPO_STORAGE_STORAGE_HANDLE_HPP
+
+#include "common.hpp"
+#include "storage-method.hpp"
+
+namespace repo {
+
+/**
+ * @brief this class defines handles to read, insert and delete data packets in storage media
+ */
+
+class StorageHandle : noncopyable
+{
+public:
+  class Error : public std::runtime_error
+  {
+  public:
+    explicit
+    Error(const std::string& what)
+      : std::runtime_error(what)
+    {
+    }
+  };
+
+  /**
+   * @brief Create a basic class object the specified storage type
+   */
+  explicit
+  StorageHandle(StorageMethod storageMethod);
+
+  virtual
+  ~StorageHandle();
+
+  /**
+   * @return storage method defined in storage-define.hpp
+   */
+  StorageMethod
+  getStorageMethod() const;
+
+  /**
+   * @brief insert data
+   * @return true on success, false otherwise
+   */
+  virtual bool
+  insertData(const Data& data) = 0;
+
+  /**
+   * @brief delete the data that exactly matches the name
+   * @return true on success, false otherwise
+   * @note It's considered successful if Data doesn't exist.
+   */
+  virtual bool
+  deleteData(const Name& name) = 0;
+
+  /**
+  * @brief find data according to the interest. This interest may contain selectors.
+  * @param[out] data Data matching Interest.
+  * @return true if Data is found, false otherwise
+  */
+  virtual bool
+  readData(const Interest& interest, Data& data) = 0;
+
+  /**
+   * @return if storage media has data packets with this name, return true, else return false
+   */
+  virtual bool
+  hasName(const Name& name) = 0;
+
+  /**
+   * @brief select any data conforms to the selector
+   * @param[out] names Data names matching @p name and @p selectors.
+   * @return true if at least one Data is found, false otherwise
+   */
+  virtual bool
+  readNameAny(const Name& name, const Selectors& selectors, vector<Name>& names) = 0;
+
+  /**
+   * @brief Get the number of Data packets stored
+   */
+  virtual size_t
+  size() = 0;
+
+private:
+  StorageMethod m_storageMethod;
+};
+
+inline
+StorageHandle::StorageHandle(StorageMethod storageMethod)
+  : m_storageMethod(storageMethod)
+{
+}
+
+inline
+StorageHandle::~StorageHandle()
+{
+}
+
+inline StorageMethod
+StorageHandle::getStorageMethod() const
+{
+  return m_storageMethod;
+}
+
+} // namespace repo
+
+#endif // REPO_STORAGE_STORAGE_HANDLE_HPP
diff --git a/src/storage/storage-method.hpp b/src/storage/storage-method.hpp
new file mode 100644
index 0000000..219be7e
--- /dev/null
+++ b/src/storage/storage-method.hpp
@@ -0,0 +1,31 @@
+/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
+/**
+ * Copyright (c) 2014,  Regents of the University of California.
+ *
+ * This file is part of NDN repo-ng (Next generation of NDN repository).
+ * See AUTHORS.md for complete list of repo-ng authors and contributors.
+ *
+ * repo-ng 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 3 of the License, or (at your option) any later version.
+ *
+ * repo-ng 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
+ * repo-ng, e.g., in COPYING.md file.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef REPO_STORAGE_STORAGE_METHOD_HPP
+#define REPO_STORAGE_STORAGE_METHOD_HPP
+
+namespace repo {
+
+enum StorageMethod {
+  STORAGE_METHOD_SQLITE = 1
+};
+
+} // namespace repo
+
+#endif // REPO_STORAGE_STORAGE_METHOD_HPP