[1068] implemented some initial steps of the updater class

- defined updater and related classes
- implemented a simple constructor and updater finder

src/lib/datasrc/client.h

@@ -143,6 +143,20 @@ public:
     /// \param name A domain name for which the search is performed.
     /// \return A \c FindResult object enclosing the search result (see above).
     virtual FindResult findZone(const isc::dns::Name& name) const = 0;
+
+    /// TBD
+    ///
+    /// We allow having a read-only data source.  For such data source
+    /// this method will result in a NotImplemented exception.
+    ///
+    /// To avoid throwing the exception accidentally with a lazy
+    /// implementation, we still keep this method pure virtual without
+    /// an implementation.  All derived classes must explicitly write the
+    /// definition of this method, even if it simply throws the NotImplemented
+    /// exception.
+    virtual ZoneUpdaterPtr startUpdateZone(const isc::dns::Name& name,
+                                           bool replace)
+        const = 0;
 };
 }
 }

src/lib/datasrc/database.cc

@@ -27,6 +27,7 @@
 
 #include <boost/foreach.hpp>
 
+using boost::shared_ptr;
 using isc::dns::Name;
 
 namespace isc {
@@ -308,5 +309,33 @@ DatabaseClient::Finder::getClass() const {
     return isc::dns::RRClass::IN();
 }
 
+ZoneUpdaterPtr
+DatabaseClient::startUpdateZone(const isc::dns::Name& name,
+                                bool replace) const
+{
+    // TODO: create a dedicated accessor
+
+    const std::pair<bool, int> zone(database_->startUpdateZone(name.toText(),
+                                                               replace));
+    if (!zone.first) {
+        return (ZoneUpdaterPtr());
+    }
+
+    // At this moment this one cannot anything except giving a finder.
+    return (ZoneUpdaterPtr(new DatabaseClient::Updater(database_,
+                                                       zone.second)));
+}
+
+DatabaseClient::Updater::Updater(shared_ptr<DatabaseAccessor> database,
+                                 int zone_id) :
+    database_(database), zone_id_(zone_id),
+    finder_(new Finder::Finder(database_, zone_id_))
+{
+}
+
+ZoneFinder&
+DatabaseClient::Updater::getFinder() {
+    return (*finder_);
+}
 }
 }

src/lib/datasrc/database.h

@@ -15,6 +15,8 @@
 #ifndef __DATABASE_DATASRC_H
 #define __DATABASE_DATASRC_H
 
+#include <boost/scoped_ptr.hpp>
+
 #include <datasrc/client.h>
 
 namespace isc {
@@ -52,6 +54,7 @@ public:
      * classes in polymorphic way.
      */
     virtual ~DatabaseAccessor() { }
+
     /**
      * \brief Retrieve a zone identifier
      *
@@ -146,7 +149,46 @@ public:
         RDATA_COLUMN = 3    ///< Full text representation of the record's RDATA
     };
 
-    /// The number of fields the columns array passed to getNextRecord should have
+    /// TBD
+    virtual std::pair<bool, int> startUpdateZone(const std::string& zone_name,
+                                                 bool replace) = 0;
+
+    /// TBD
+    virtual void commitUpdateZone() = 0;
+
+    /// TBD
+    virtual void rollbackUpdateZone() = 0;
+
+    /// TBD
+    /// This is "dumb"; doesn't inspect the content of columns.
+    /// The zone is the one specified in startUpdateZone().
+    virtual void addRecordToZone(const std::vector<std::string>& columns) = 0;
+
+    /// TBD
+    ///
+    /// note: in dynamic update or IXFR, TTL may also be specified, but
+    /// we intentionally ignore that in this interface, because it's not
+    /// guaranteed that all records have the same TTL (unlike the RRset
+    /// assumption) and there can even be multiple records for the same name,
+    /// type and rdata with different TTLs.  If we only delete one of them,
+    /// subsequent lookup will still return a positive answer, which would
+    /// be confusing.  It's a higher layer's responsibility to check if
+    /// there is at least one record in the database that has the given
+    /// TTL.
+    virtual void deleteRecordInZone(
+        const std::vector<std::string>& params) = 0;
+
+    /// TBD
+    /// Compliant database should support the following columns:
+    /// name, rname, ttl, rdtype, sigtype, rdata
+    /// (even though their internal representation may be different).
+    static const size_t ADD_COLUMN_COUNT = 6;
+
+    /// TBD
+    static const size_t DEL_PARAM_COUNT = 3;
+
+    /// The number of fields the columns array passed to getNextRecord should
+    /// have.
     static const size_t COLUMN_COUNT = 4;
 
     /**
@@ -291,6 +333,18 @@ public:
         boost::shared_ptr<DatabaseAccessor> database_;
         const int zone_id_;
     };
+
+    class Updater : public ZoneUpdater {
+    public:
+        Updater(boost::shared_ptr<DatabaseAccessor> database, int zone_id);
+        virtual ZoneFinder& getFinder();
+
+    private:
+        boost::shared_ptr<DatabaseAccessor> database_;
+        const int zone_id_;
+        boost::scoped_ptr<Finder::Finder> finder_;
+    };
+
     /**
      * \brief Find a zone in the database
      *
@@ -307,6 +361,10 @@ public:
      */
     virtual FindResult findZone(const isc::dns::Name& name) const;
 
+    /// TBD
+    virtual ZoneUpdaterPtr startUpdateZone(const isc::dns::Name& name,
+                                           bool replace) const;
+
 private:
     /// \brief Our database.
     const boost::shared_ptr<DatabaseAccessor> database_;
@@ -315,4 +373,8 @@ private:
 }
 }
 
-#endif
+#endif  // __DATABASE_DATASRC_H
+
+// Local Variables:
+// mode: c++
+// End:

src/lib/datasrc/memory_datasrc.cc

@@ -17,6 +17,8 @@
 #include <boost/shared_ptr.hpp>
 #include <boost/bind.hpp>
 
+#include <exceptions/exceptions.h>
+
 #include <dns/name.h>
 #include <dns/rrclass.h>
 #include <dns/rrsetlist.h>
@@ -703,5 +705,12 @@ InMemoryClient::findZone(const isc::dns::Name& name) const {
     return (FindResult(impl_->zone_table.findZone(name).code,
                        impl_->zone_table.findZone(name).zone));
 }
+
+ZoneUpdaterPtr
+InMemoryClient::startUpdateZone(const isc::dns::Name&, bool) const {
+    // TODO: once #1067 is merged, we should replace Unexpected with
+    // NotImplemented.
+    isc_throw(isc::Unexpected, "Update attempt on in memory data source");
+}
 } // end of namespace datasrc
 } // end of namespace dns

src/lib/datasrc/memory_datasrc.h

@@ -258,6 +258,11 @@ public:
     /// For other details see \c DataSourceClient::findZone().
     virtual FindResult findZone(const isc::dns::Name& name) const;
 
+    /// In-memory data source is read-only, so this derived method will
+    /// result in a NotImplemented (once merged) exception.
+    virtual ZoneUpdaterPtr startUpdateZone(const isc::dns::Name& name,
+                                           bool replace) const;
+
 private:
     // TODO: Do we still need the PImpl if nobody should manipulate this class
     // directly any more (it should be handled through DataSourceClient)?

src/lib/datasrc/tests/database_unittest.cc

@@ -31,14 +31,21 @@ using namespace isc::datasrc;
 using namespace std;
 using namespace boost;
 using isc::dns::Name;
+using isc::dns::RRType;
+using isc::dns::RRTTL;
 
 namespace {
 
+const int READONLY_ZONE_ID = 42;
+const int WRITABLE_ZONE_ID = 4200;
+
 /*
  * A virtual database database that pretends it contains single zone --
  * example.org.
  */
 class MockAccessor : public DatabaseAccessor {
+    typedef std::map<std::string, std::vector< std::vector<std::string> > >
+    RECORDS;
 public:
     MockAccessor() : search_running_(false),
                        database_name_("mock_database")
@@ -46,9 +53,12 @@ public:
         fillData();
     }
 
-    virtual std::pair<bool, int> getZone(const Name& name) const {
-        if (name == Name("example.org")) {
-            return (std::pair<bool, int>(true, 42));
+    virtual pair<bool, int> getZone(const Name& name) const {
+        return (getZone(name.toText()));
+    }
+    pair<bool, int> getZone(const string& name) const {
+        if (name == "example.org.") {
+            return (std::pair<bool, int>(true, READONLY_ZONE_ID));
         } else {
             return (std::pair<bool, int>(false, 0));
         }
@@ -72,16 +82,13 @@ public:
         // we're not aiming for efficiency in this test, simply
         // copy the relevant vector from records
         cur_record = 0;
-        if (zone_id == 42) {
-            if (records.count(name) > 0) {
-                cur_name = records.find(name)->second;
-            } else {
-                cur_name.clear();
-            }
+        const RECORDS& cur_records = getRecords(zone_id);
+        if (cur_records.count(name) > 0) {
+            cur_name = cur_records.find(name)->second;
         } else {
             cur_name.clear();
         }
-    };
+    }
 
     virtual bool getNextRecord(std::string columns[], size_t column_count) {
         if (searched_name_ == "dsexception.in.getnext.") {
@@ -119,7 +126,10 @@ public:
         return (database_name_);
     }
 private:
-    std::map<std::string, std::vector< std::vector<std::string> > > records;
+    RECORDS readonly_records;
+    RECORDS update_records;
+    RECORDS empty_records;
+
     // used as internal index for getNextRecord()
     size_t cur_record;
     // used as temporary storage after searchForRecord() and during
@@ -137,6 +147,15 @@ private:
 
     const std::string database_name_;
 
+    const RECORDS& getRecords(int zone_id) const {
+        if (zone_id == READONLY_ZONE_ID) {
+            return (readonly_records);
+        } else if (zone_id == WRITABLE_ZONE_ID) {
+            return (update_records);
+        }
+        return (empty_records);
+    }
+
     // Adds one record to the current name in the database
     // The actual data will not be added to 'records' until
     // addCurName() is called
@@ -156,8 +175,8 @@ private:
     // to the actual fake database. This will clear cur_name,
     // so we can immediately start adding new records.
     void addCurName(const std::string& name) {
-        ASSERT_EQ(0, records.count(name));
-        records[name] = cur_name;
+        ASSERT_EQ(0, readonly_records.count(name));
+        readonly_records[name] = cur_name;
         cur_name.clear();
     }
 
@@ -264,10 +283,34 @@ private:
         addRecord("RRSIG", "3600", "TXT", "A 5 3 3600 20000101000000 20000201000000 12345 example.org. FAKEFAKEFAKE");
         addCurName("badsigtype.example.org.");
     }
+
+    virtual pair<bool, int> startUpdateZone(const std::string& zone_name,
+                                            bool replace)
+    {
+        const pair<bool, int> zone_info = getZone(zone_name);
+        if (!zone_info.first) {
+            return (pair<bool, int>(false, 0));
+        }
+
+        // Prepare the record set for update.  If replacing the existing one,
+        // we use an empty set; otherwise we use a writable copy of the
+        // original.
+        if (replace) {
+            update_records.clear();
+        } else {
+            update_records = readonly_records;
+        }
+
+        return (pair<bool, int>(true, WRITABLE_ZONE_ID));
+    }
+    virtual void commitUpdateZone() {}
+    virtual void rollbackUpdateZone() {}
+    virtual void addRecordToZone(const vector<string>&) {}
+    virtual void deleteRecordInZone(const vector<string>&) {}
 };
 
 class DatabaseClientTest : public ::testing::Test {
-public:
+protected:
     DatabaseClientTest() {
         createClient();
     }
@@ -285,6 +328,10 @@ public:
     shared_ptr<DatabaseClient> client_;
     const std::string database_name_;
 
+    const std::vector<std::string> empty_rdatas; // for NXRRSET/NXDOMAIN
+    std::vector<std::string> expected_rdatas;
+    std::vector<std::string> expected_sig_rdatas;
+
     /**
      * Check the zone finder is a valid one and references the zone ID and
      * database available here.
@@ -295,7 +342,7 @@ public:
             dynamic_pointer_cast<DatabaseClient::Finder>(zone.zone_finder));
         ASSERT_NE(shared_ptr<DatabaseClient::Finder>(), finder) <<
             "Wrong type of finder";
-        EXPECT_EQ(42, finder->zone_id());
+        EXPECT_EQ(READONLY_ZONE_ID, finder->zone_id());
         EXPECT_EQ(current_database_, &finder->database());
     }
 };
@@ -325,6 +372,17 @@ TEST_F(DatabaseClientTest, noAccessorException) {
                  isc::InvalidParameter);
 }
 
+TEST_F(DatabaseClientTest, startUpdate) {
+    // startUpdate will succeed only when there's an exact match zone.
+
+    EXPECT_EQ(ZoneUpdaterPtr(),
+              client_->startUpdateZone(Name("example.com"), false));
+    EXPECT_NE(ZoneUpdaterPtr(),
+              client_->startUpdateZone(Name("example.org"), false));
+    EXPECT_EQ(ZoneUpdaterPtr(),
+              client_->startUpdateZone(Name("sub.example.org"), false));
+}
+
 namespace {
 // checks if the given rrset matches the
 // given name, class, type and rdatas
@@ -346,7 +404,7 @@ checkRRset(isc::dns::ConstRRsetPtr rrset,
 }
 
 void
-doFindTest(shared_ptr<DatabaseClient::Finder> finder,
+doFindTest(ZoneFinder& finder,
            const isc::dns::Name& name,
            const isc::dns::RRType& type,
            const isc::dns::RRType& expected_type,
@@ -356,15 +414,15 @@ doFindTest(shared_ptr<DatabaseClient::Finder> finder,
            const std::vector<std::string>& expected_sig_rdatas)
 {
     ZoneFinder::FindResult result =
-        finder->find(name, type, NULL, ZoneFinder::FIND_DEFAULT);
+        finder.find(name, type, NULL, ZoneFinder::FIND_DEFAULT);
     ASSERT_EQ(expected_result, result.code) << name << " " << type;
     if (expected_rdatas.size() > 0) {
-        checkRRset(result.rrset, name, finder->getClass(),
+        checkRRset(result.rrset, name, finder.getClass(),
                    expected_type, expected_ttl, expected_rdatas);
 
         if (expected_sig_rdatas.size() > 0) {
             checkRRset(result.rrset->getRRsig(), name,
-                       finder->getClass(), isc::dns::RRType::RRSIG(),
+                       finder.getClass(), isc::dns::RRType::RRSIG(),
                        expected_ttl, expected_sig_rdatas);
         } else {
             EXPECT_EQ(isc::dns::RRsetPtr(), result.rrset->getRRsig());
@@ -380,15 +438,13 @@ TEST_F(DatabaseClientTest, find) {
     ASSERT_EQ(result::SUCCESS, zone.code);
     shared_ptr<DatabaseClient::Finder> finder(
         dynamic_pointer_cast<DatabaseClient::Finder>(zone.zone_finder));
-    EXPECT_EQ(42, finder->zone_id());
+    EXPECT_EQ(READONLY_ZONE_ID, finder->zone_id());
     EXPECT_FALSE(current_database_->searchRunning());
-    std::vector<std::string> expected_rdatas;
-    std::vector<std::string> expected_sig_rdatas;
 
     expected_rdatas.clear();
     expected_sig_rdatas.clear();
     expected_rdatas.push_back("192.0.2.1");
-    doFindTest(finder, isc::dns::Name("www.example.org."),
+    doFindTest(*finder, isc::dns::Name("www.example.org."),
                isc::dns::RRType::A(), isc::dns::RRType::A(),
                isc::dns::RRTTL(3600),
                ZoneFinder::SUCCESS,
@@ -399,7 +455,7 @@ TEST_F(DatabaseClientTest, find) {
     expected_sig_rdatas.clear();
     expected_rdatas.push_back("192.0.2.1");
     expected_rdatas.push_back("192.0.2.2");
-    doFindTest(finder, isc::dns::Name("www2.example.org."),
+    doFindTest(*finder, isc::dns::Name("www2.example.org."),
                isc::dns::RRType::A(), isc::dns::RRType::A(),
                isc::dns::RRTTL(3600),
                ZoneFinder::SUCCESS,
@@ -410,7 +466,7 @@ TEST_F(DatabaseClientTest, find) {
     expected_sig_rdatas.clear();
     expected_rdatas.push_back("2001:db8::1");
     expected_rdatas.push_back("2001:db8::2");
-    doFindTest(finder, isc::dns::Name("www.example.org."),
+    doFindTest(*finder, isc::dns::Name("www.example.org."),
                isc::dns::RRType::AAAA(), isc::dns::RRType::AAAA(),
                isc::dns::RRTTL(3600),
                ZoneFinder::SUCCESS,
@@ -419,7 +475,7 @@ TEST_F(DatabaseClientTest, find) {
 
     expected_rdatas.clear();
     expected_sig_rdatas.clear();
-    doFindTest(finder, isc::dns::Name("www.example.org."),
+    doFindTest(*finder, isc::dns::Name("www.example.org."),
                isc::dns::RRType::TXT(), isc::dns::RRType::TXT(),
                isc::dns::RRTTL(3600),
                ZoneFinder::NXRRSET,
@@ -429,7 +485,7 @@ TEST_F(DatabaseClientTest, find) {
     expected_rdatas.clear();
     expected_sig_rdatas.clear();
     expected_rdatas.push_back("www.example.org.");
-    doFindTest(finder, isc::dns::Name("cname.example.org."),
+    doFindTest(*finder, isc::dns::Name("cname.example.org."),
                isc::dns::RRType::A(), isc::dns::RRType::CNAME(),
                isc::dns::RRTTL(3600),
                ZoneFinder::CNAME,
@@ -439,7 +495,7 @@ TEST_F(DatabaseClientTest, find) {
     expected_rdatas.clear();
     expected_sig_rdatas.clear();
     expected_rdatas.push_back("www.example.org.");
-    doFindTest(finder, isc::dns::Name("cname.example.org."),
+    doFindTest(*finder, isc::dns::Name("cname.example.org."),
                isc::dns::RRType::CNAME(), isc::dns::RRType::CNAME(),
                isc::dns::RRTTL(3600),
                ZoneFinder::SUCCESS,
@@ -448,7 +504,7 @@ TEST_F(DatabaseClientTest, find) {
 
     expected_rdatas.clear();
     expected_sig_rdatas.clear();
-    doFindTest(finder, isc::dns::Name("doesnotexist.example.org."),
+    doFindTest(*finder, isc::dns::Name("doesnotexist.example.org."),
                isc::dns::RRType::A(), isc::dns::RRType::A(),
                isc::dns::RRTTL(3600),
                ZoneFinder::NXDOMAIN,
@@ -460,7 +516,7 @@ TEST_F(DatabaseClientTest, find) {
     expected_rdatas.push_back("192.0.2.1");
     expected_sig_rdatas.push_back("A 5 3 3600 20000101000000 20000201000000 12345 example.org. FAKEFAKEFAKE");
     expected_sig_rdatas.push_back("A 5 3 3600 20000101000000 20000201000000 12346 example.org. FAKEFAKEFAKE");
-    doFindTest(finder, isc::dns::Name("signed1.example.org."),
+    doFindTest(*finder, isc::dns::Name("signed1.example.org."),
                isc::dns::RRType::A(), isc::dns::RRType::A(),
                isc::dns::RRTTL(3600),
                ZoneFinder::SUCCESS,
@@ -472,7 +528,7 @@ TEST_F(DatabaseClientTest, find) {
     expected_rdatas.push_back("2001:db8::1");
     expected_rdatas.push_back("2001:db8::2");
     expected_sig_rdatas.push_back("AAAA 5 3 3600 20000101000000 20000201000000 12345 example.org. FAKEFAKEFAKE");
-    doFindTest(finder, isc::dns::Name("signed1.example.org."),
+    doFindTest(*finder, isc::dns::Name("signed1.example.org."),
                isc::dns::RRType::AAAA(), isc::dns::RRType::AAAA(),
                isc::dns::RRTTL(3600),
                ZoneFinder::SUCCESS,
@@ -481,7 +537,7 @@ TEST_F(DatabaseClientTest, find) {
 
     expected_rdatas.clear();
     expected_sig_rdatas.clear();
-    doFindTest(finder, isc::dns::Name("signed1.example.org."),
+    doFindTest(*finder, isc::dns::Name("signed1.example.org."),
                isc::dns::RRType::TXT(), isc::dns::RRType::TXT(),
                isc::dns::RRTTL(3600),
                ZoneFinder::NXRRSET,
@@ -492,7 +548,7 @@ TEST_F(DatabaseClientTest, find) {
     expected_sig_rdatas.clear();
     expected_rdatas.push_back("www.example.org.");
     expected_sig_rdatas.push_back("CNAME 5 3 3600 20000101000000 20000201000000 12345 example.org. FAKEFAKEFAKE");
-    doFindTest(finder, isc::dns::Name("signedcname1.example.org."),
+    doFindTest(*finder, isc::dns::Name("signedcname1.example.org."),
                isc::dns::RRType::A(), isc::dns::RRType::CNAME(),
                isc::dns::RRTTL(3600),
                ZoneFinder::CNAME,
@@ -504,7 +560,7 @@ TEST_F(DatabaseClientTest, find) {
     expected_rdatas.push_back("192.0.2.1");
     expected_sig_rdatas.push_back("A 5 3 3600 20000101000000 20000201000000 12345 example.org. FAKEFAKEFAKE");
     expected_sig_rdatas.push_back("A 5 3 3600 20000101000000 20000201000000 12346 example.org. FAKEFAKEFAKE");
-    doFindTest(finder, isc::dns::Name("signed2.example.org."),
+    doFindTest(*finder, isc::dns::Name("signed2.example.org."),
                isc::dns::RRType::A(), isc::dns::RRType::A(),
                isc::dns::RRTTL(3600),
                ZoneFinder::SUCCESS,
@@ -516,7 +572,7 @@ TEST_F(DatabaseClientTest, find) {
     expected_rdatas.push_back("2001:db8::2");
     expected_rdatas.push_back("2001:db8::1");
     expected_sig_rdatas.push_back("AAAA 5 3 3600 20000101000000 20000201000000 12345 example.org. FAKEFAKEFAKE");
-    doFindTest(finder, isc::dns::Name("signed2.example.org."),
+    doFindTest(*finder, isc::dns::Name("signed2.example.org."),
                isc::dns::RRType::AAAA(), isc::dns::RRType::AAAA(),
                isc::dns::RRTTL(3600),
                ZoneFinder::SUCCESS,
@@ -525,7 +581,7 @@ TEST_F(DatabaseClientTest, find) {
 
     expected_rdatas.clear();
     expected_sig_rdatas.clear();
-    doFindTest(finder, isc::dns::Name("signed2.example.org."),
+    doFindTest(*finder, isc::dns::Name("signed2.example.org."),
                isc::dns::RRType::TXT(), isc::dns::RRType::TXT(),
                isc::dns::RRTTL(3600),
                ZoneFinder::NXRRSET,
@@ -536,7 +592,7 @@ TEST_F(DatabaseClientTest, find) {
     expected_sig_rdatas.clear();
     expected_rdatas.push_back("www.example.org.");
     expected_sig_rdatas.push_back("CNAME 5 3 3600 20000101000000 20000201000000 12345 example.org. FAKEFAKEFAKE");
-    doFindTest(finder, isc::dns::Name("signedcname2.example.org."),
+    doFindTest(*finder, isc::dns::Name("signedcname2.example.org."),
                isc::dns::RRType::A(), isc::dns::RRType::CNAME(),
                isc::dns::RRTTL(3600),
                ZoneFinder::CNAME,
@@ -548,7 +604,7 @@ TEST_F(DatabaseClientTest, find) {
     expected_sig_rdatas.clear();
     expected_rdatas.push_back("192.0.2.1");
     expected_sig_rdatas.push_back("A 5 3 3600 20000101000000 20000201000000 12345 example.org. FAKEFAKEFAKE");
-    doFindTest(finder, isc::dns::Name("acnamesig1.example.org."),
+    doFindTest(*finder, isc::dns::Name("acnamesig1.example.org."),
                isc::dns::RRType::A(), isc::dns::RRType::A(),
                isc::dns::RRTTL(3600),
                ZoneFinder::SUCCESS,
@@ -559,7 +615,7 @@ TEST_F(DatabaseClientTest, find) {
     expected_sig_rdatas.clear();
     expected_rdatas.push_back("192.0.2.1");
     expected_sig_rdatas.push_back("A 5 3 3600 20000101000000 20000201000000 12345 example.org. FAKEFAKEFAKE");
-    doFindTest(finder, isc::dns::Name("acnamesig2.example.org."),
+    doFindTest(*finder, isc::dns::Name("acnamesig2.example.org."),
                isc::dns::RRType::A(), isc::dns::RRType::A(),
                isc::dns::RRTTL(3600),
                ZoneFinder::SUCCESS,
@@ -570,7 +626,7 @@ TEST_F(DatabaseClientTest, find) {
     expected_sig_rdatas.clear();
     expected_rdatas.push_back("192.0.2.1");
     expected_sig_rdatas.push_back("A 5 3 3600 20000101000000 20000201000000 12345 example.org. FAKEFAKEFAKE");
-    doFindTest(finder, isc::dns::Name("acnamesig3.example.org."),
+    doFindTest(*finder, isc::dns::Name("acnamesig3.example.org."),
                isc::dns::RRType::A(), isc::dns::RRType::A(),
                isc::dns::RRTTL(3600),
                ZoneFinder::SUCCESS,
@@ -581,7 +637,7 @@ TEST_F(DatabaseClientTest, find) {
     expected_sig_rdatas.clear();
     expected_rdatas.push_back("192.0.2.1");
     expected_rdatas.push_back("192.0.2.2");
-    doFindTest(finder, isc::dns::Name("ttldiff1.example.org."),
+    doFindTest(*finder, isc::dns::Name("ttldiff1.example.org."),
                isc::dns::RRType::A(), isc::dns::RRType::A(),
                isc::dns::RRTTL(360),
                ZoneFinder::SUCCESS,
@@ -592,14 +648,13 @@ TEST_F(DatabaseClientTest, find) {
     expected_sig_rdatas.clear();
     expected_rdatas.push_back("192.0.2.1");
     expected_rdatas.push_back("192.0.2.2");
-    doFindTest(finder, isc::dns::Name("ttldiff2.example.org."),
+    doFindTest(*finder, isc::dns::Name("ttldiff2.example.org."),
                isc::dns::RRType::A(), isc::dns::RRType::A(),
                isc::dns::RRTTL(360),
                ZoneFinder::SUCCESS,
                expected_rdatas, expected_sig_rdatas);
     EXPECT_FALSE(current_database_->searchRunning());
 
-
     EXPECT_THROW(finder->find(isc::dns::Name("badcname1.example.org."),
                                               isc::dns::RRType::A(),
                                               NULL, ZoneFinder::FIND_DEFAULT),
@@ -676,7 +731,7 @@ TEST_F(DatabaseClientTest, find) {
     expected_sig_rdatas.clear();
     expected_rdatas.push_back("192.0.2.1");
     expected_sig_rdatas.push_back("A 5 3 3600 20000101000000 20000201000000 12345 example.org. FAKEFAKEFAKE");
-    doFindTest(finder, isc::dns::Name("badsigtype.example.org."),
+    doFindTest(*finder, isc::dns::Name("badsigtype.example.org."),
                isc::dns::RRType::A(), isc::dns::RRType::A(),
                isc::dns::RRTTL(3600),
                ZoneFinder::SUCCESS,
@@ -684,4 +739,30 @@ TEST_F(DatabaseClientTest, find) {
     EXPECT_FALSE(current_database_->searchRunning());
 }
 
+TEST_F(DatabaseClientTest, updaterFinder) {
+    ZoneUpdaterPtr updater = client_->startUpdateZone(Name("example.org"),
+                                                      false);
+    ASSERT_TRUE(updater);
+
+    // If this update isn't replacing the zone, the finder should work
+    // just like the normal find() case.
+    EXPECT_EQ(WRITABLE_ZONE_ID, dynamic_cast<DatabaseClient::Finder&>(
+                  updater->getFinder()).zone_id());
+    expected_rdatas.clear();
+    expected_rdatas.push_back("192.0.2.1");
+    doFindTest(updater->getFinder(), Name("www.example.org."),
+               RRType::A(), RRType::A(), RRTTL(3600), ZoneFinder::SUCCESS,
+               expected_rdatas, empty_rdatas);
+
+    // When replacing the zone, the updater's finder shouldn't see anything
+    // in the zone until something is added.
+    updater = client_->startUpdateZone(Name("example.org"), true);
+    ASSERT_TRUE(updater);
+    EXPECT_EQ(WRITABLE_ZONE_ID, dynamic_cast<DatabaseClient::Finder&>(
+                  updater->getFinder()).zone_id());
+    doFindTest(updater->getFinder(), Name("www.example.org."),
+               RRType::A(), RRType::A(), RRTTL(3600), ZoneFinder::NXDOMAIN,
+               empty_rdatas, empty_rdatas);
+}
+
 }

src/lib/datasrc/tests/memory_datasrc_unittest.cc

@@ -158,6 +158,11 @@ TEST_F(InMemoryClientTest, getZoneCount) {
     EXPECT_EQ(2, memory_client.getZoneCount());
 }
 
+TEST_F(InMemoryClientTest, startUpdateZone) {
+    EXPECT_THROW(memory_client.startUpdateZone(Name("example.org"), false),
+                 isc::Unexpected);
+}
+
 // A helper callback of masterLoad() used in InMemoryZoneFinderTest.
 void
 setRRset(RRsetPtr rrset, vector<RRsetPtr*>::iterator& it) {
@@ -1058,5 +1063,4 @@ TEST_F(InMemoryZoneFinderTest, getFileName) {
     EXPECT_EQ(TEST_DATA_DIR "/root.zone", zone_finder_.getFileName());
     EXPECT_TRUE(rootzone.getFileName().empty());
 }
-
 }

src/lib/datasrc/zone.h

@@ -207,8 +207,18 @@ typedef boost::shared_ptr<ZoneFinder> ZoneFinderPtr;
 /// \brief A pointer-like type pointing to a \c ZoneFinder object.
 typedef boost::shared_ptr<const ZoneFinder> ConstZoneFinderPtr;
 
-}
-}
+/// The base class to make updates to a single zone.
+class ZoneUpdater {
+public:
+    /// TBD
+    virtual ZoneFinder& getFinder() = 0;
+};
+
+/// \brief A pointer-like type pointing to a \c ZoneUpdater object.
+typedef boost::shared_ptr<ZoneUpdater> ZoneUpdaterPtr;
+
+} // end of datasrc
+} // end of isc
 
 #endif  // __ZONE_H