[1976] Preserve configuration in the ClientList

And change the parameter type in configure, since we want to preserve
the exact instance and we don't want to do a (deep) copy.

src/lib/datasrc/client_list.cc

@@ -26,15 +26,18 @@ namespace isc {
 namespace datasrc {
 
 void
-ConfigurableClientList::configure(const Element& config, bool) {
+ConfigurableClientList::configure(const ConstElementPtr& config, bool) {
+    if (!config) {
+        isc_throw(isc::BadValue, "NULL configuration passed");
+    }
     // TODO: Implement the cache
     // TODO: Implement recycling from the old configuration.
     size_t i(0); // Outside of the try to be able to access it in the catch
     try {
         vector<DataSourceInfo> new_data_sources;
-        for (; i < config.size(); ++i) {
+        for (; i < config->size(); ++i) {
             // Extract the parameters
-            const ConstElementPtr dconf(config.get(i));
+            const ConstElementPtr dconf(config->get(i));
             const ConstElementPtr typeElem(dconf->get("type"));
             if (typeElem == ConstElementPtr()) {
                 isc_throw(ConfigurationError, "Missing the type option in "
@@ -56,6 +59,7 @@ ConfigurableClientList::configure(const Element& config, bool) {
         // ready. So just put it there and let the old one die when we exit
         // the scope.
         data_sources_.swap(new_data_sources);
+        configuration_ = config;
     } catch (const TypeError& te) {
         isc_throw(ConfigurationError, "Malformed configuration at data source "
                   "no. " << i << ": " << te.what());

src/lib/datasrc/client_list.h

@@ -185,6 +185,9 @@ typedef boost::shared_ptr<const ClientList> ConstClientListPtr;
 /// inherited except for tests.
 class ConfigurableClientList : public ClientList {
 public:
+    ConfigurableClientList() :
+        configuration_(new isc::data::ListElement)
+    {}
     /// \brief Exception thrown when there's an error in configuration.
     class ConfigurationError : public Exception {
     public:
@@ -212,7 +215,17 @@ public:
     ///     client.
     /// \throw ConfigurationError if the configuration is invalid in some
     ///     sense.
-    void configure(const data::Element& configuration, bool allow_cache);
+    /// \throw BadValue if configuration is NULL
+    void configure(const isc::data::ConstElementPtr& configuration,
+                   bool allow_cache);
+
+    /// \brief Returns the currently active configuration.
+    ///
+    /// In case configure was not called yet, it returns an empty
+    /// list, which corresponds to the default content.
+    const isc::data::ConstElementPtr& getConfiguration() const {
+        return (configuration_);
+    }
 
     /// \brief Implementation of the ClientList::find.
     virtual FindResult find(const dns::Name& zone,
@@ -273,6 +286,9 @@ protected:
     virtual DataSourcePair getDataSourceClient(const std::string& type,
                                                const data::ConstElementPtr&
                                                configuration);
+private:
+    /// \brief Currently active configuration.
+    isc::data::ConstElementPtr configuration_;
 public:
     /// \brief Access to the data source clients.
     ///

src/lib/datasrc/tests/client_list_unittest.cc

@@ -353,8 +353,10 @@ TEST_F(ListTest, multiBestMatch) {
 // Check the configuration is empty when the list is empty
 TEST_F(ListTest, configureEmpty) {
     ConstElementPtr elem(new ListElement);
-    list_->configure(*elem, true);
+    list_->configure(elem, true);
     EXPECT_TRUE(list_->getDataSources().empty());
+    // Check the exact configuration is preserved
+    EXPECT_EQ(elem, list_->getConfiguration());
 }
 
 // Check we can get multiple data sources and they are in the right order.
@@ -371,10 +373,12 @@ TEST_F(ListTest, configureMulti) {
         "   \"params\": {}"
         "}]"
     ));
-    list_->configure(*elem, true);
+    list_->configure(elem, true);
     EXPECT_EQ(2, list_->getDataSources().size());
     checkDS(0, "type1", "{}");
     checkDS(1, "type2", "{}");
+    // Check the exact configuration is preserved
+    EXPECT_EQ(elem, list_->getConfiguration());
 }
 
 // Check we can pass whatever we want to the params
@@ -397,7 +401,7 @@ TEST_F(ListTest, configureParams) {
             "   \"cache\": \"off\","
             "   \"params\": ") + *param +
             "}]"));
-        list_->configure(*elem, true);
+        list_->configure(elem, true);
         EXPECT_EQ(1, list_->getDataSources().size());
         checkDS(0, "t", *param);
     }
@@ -425,12 +429,12 @@ TEST_F(ListTest, wrongConfig) {
         NULL
     };
     // Put something inside to see it survives the exception
-    list_->configure(*config_elem_, true);
+    list_->configure(config_elem_, true);
     checkDS(0, "test_type", "{}");
     for (const char** config(configs); *config; ++config) {
         SCOPED_TRACE(*config);
         ConstElementPtr elem(Element::fromJSON(*config));
-        EXPECT_THROW(list_->configure(*elem, true),
+        EXPECT_THROW(list_->configure(elem, true),
                      ConfigurableClientList::ConfigurationError);
         // Still untouched
         checkDS(0, "test_type", "{}");
@@ -444,7 +448,7 @@ TEST_F(ListTest, defaults) {
         "{"
         "   \"type\": \"type1\""
         "}]"));
-    list_->configure(*elem, true);
+    list_->configure(elem, true);
     EXPECT_EQ(1, list_->getDataSources().size());
     checkDS(0, "type1", "null");
 }
@@ -452,11 +456,11 @@ TEST_F(ListTest, defaults) {
 // Check we can call the configure multiple times, to change the configuration
 TEST_F(ListTest, reconfigure) {
     ConstElementPtr empty(new ListElement);
-    list_->configure(*config_elem_, true);
+    list_->configure(config_elem_, true);
     checkDS(0, "test_type", "{}");
-    list_->configure(*empty, true);
+    list_->configure(empty, true);
     EXPECT_TRUE(list_->getDataSources().empty());
-    list_->configure(*config_elem_, true);
+    list_->configure(config_elem_, true);
     checkDS(0, "test_type", "{}");
 }
 
@@ -466,9 +470,9 @@ TEST_F(ListTest, dataSrcError) {
         "{"
         "   \"type\": \"error\""
         "}]"));
-    list_->configure(*config_elem_, true);
+    list_->configure(config_elem_, true);
     checkDS(0, "test_type", "{}");
-    EXPECT_THROW(list_->configure(*elem, true), DataSourceError);
+    EXPECT_THROW(list_->configure(elem, true), DataSourceError);
     checkDS(0, "test_type", "{}");
 }