[3671] Created a function to read leases from multiple files.

src/lib/dhcpsrv/memfile_lease_mgr.cc

-// Copyright (C) 2012-2014 Internet Systems Consortium, Inc. ("ISC")
+// Copyright (C) 2012-2015 Internet Systems Consortium, Inc. ("ISC")
 //
 // Permission to use, copy, modify, and/or distribute this software for any
 // purpose with or without fee is hereby granted, provided that the above
@@ -36,20 +36,14 @@ Memfile_LeaseMgr::Memfile_LeaseMgr(const ParameterMap& parameters)
     if (universe == "4") {
         std::string file4 = initLeaseFilePath(V4);
         if (!file4.empty()) {
-            lease_file4_.reset(new CSVLeaseFile4(file4));
-            lease_file4_->open();
-            storage4_.clear();
-            LeaseFileLoader::load<Lease4>(*lease_file4_, storage4_,
-                                          MAX_LEASE_ERRORS);
+            loadLeasesFromFiles<Lease4, CSVLeaseFile4>(file4, lease_file4_,
+                                                       storage4_);
         }
     } else {
         std::string file6 = initLeaseFilePath(V6);
         if (!file6.empty()) {
-            lease_file6_.reset(new CSVLeaseFile6(file6));
-            lease_file6_->open();
-            storage6_.clear();
-            LeaseFileLoader::load<Lease6>(*lease_file6_, storage6_,
-                                          MAX_LEASE_ERRORS);
+            loadLeasesFromFiles<Lease6, CSVLeaseFile6>(file6, lease_file6_,
+                                                       storage6_);
         }
     }
 
@@ -480,3 +474,13 @@ Memfile_LeaseMgr::initLeaseFilePath(Universe u) {
     return (lease_file);
 }
 
+template<typename LeaseObjectType, typename LeaseFileType, typename StorageType>
+void Memfile_LeaseMgr::
+loadLeasesFromFiles(const std::string& filename,
+                    boost::shared_ptr<LeaseFileType>& lease_file,
+                    StorageType& storage) {
+    lease_file.reset(new LeaseFileType(filename));
+    lease_file->open();
+    storage.clear();
+    LeaseFileLoader::load<LeaseObjectType>(*lease_file, storage, MAX_LEASE_ERRORS);
+}

src/lib/dhcpsrv/memfile_lease_mgr.h

@@ -21,6 +21,8 @@
 #include <dhcpsrv/inmemory_lease_storage.h>
 #include <dhcpsrv/lease_mgr.h>
 
+#include <boost/shared_ptr.hpp>
+
 namespace isc {
 namespace dhcp {
 
@@ -328,7 +330,7 @@ public:
     /// server shut down.
     bool persistLeases(Universe u) const;
 
-protected:
+private:
 
     /// @brief Initialize the location of the lease file.
     ///
@@ -347,6 +349,42 @@ protected:
     /// argument to this function.
     std::string initLeaseFilePath(Universe u);
 
+    /// @brief Load leases from the persistent storage.
+    ///
+    /// This method loads DHCPv4 or DHCPv6 leases from lease files in the
+    /// following order:
+    /// - leases from the <filename>.2
+    /// - leases from the <filename>.1
+    /// - leases from the <filename>
+    ///
+    /// If any of the files doesn't exist the method proceeds to reading
+    /// leases from the subsequent file. If the <filename> doesn't exist
+    /// it is created.
+    ///
+    /// When the method successfully reads leases from the files, it leaves
+    /// the file <filename> open and its internal pointer is set to the
+    /// end of file. The server will append lease entries to this file as
+    /// a result of processing new messages from the clients.
+    ///
+    /// The <filename>.2 and <filename>.1 are the products of the lease
+    /// file cleanups (LFC). See: http://kea.isc.org/wiki/LFCDesign for
+    /// details.
+    ///
+    /// @param filename Name of the lease file.
+    /// @param lease_file An object representing a lease file to which
+    /// the server will store lease updates.
+    /// @param storage A storage for leases read from the lease file.
+    /// @tparam LeaseObjectType @c Lease4 or @c Lease6.
+    /// @tparam LeaseFileType @c CSVLeaseFile4 or @c CSVLeaseFile6.
+    /// @tparam StorageType @c Lease4Storage or @c Lease6Storage.
+    ///
+    /// @throw CSVFileError when parsing any of the lease files fails.
+    template<typename LeaseObjectType, typename LeaseFileType,
+             typename StorageType>
+    void loadLeasesFromFiles(const std::string& filename,
+                             boost::shared_ptr<LeaseFileType>& lease_file,
+                             StorageType& storage);
+
     /// @brief stores IPv4 leases
     Lease4Storage storage4_;
 
@@ -364,4 +402,4 @@ protected:
 }; // end of isc::dhcp namespace
 }; // end of isc namespace
 
-#endif // MEMFILE_LEASE_MGR
+#endif // MEMFILE_LEASE_MGR_H