introduce ConfigurationBuilder

src/utils/configuration.cpp

@@ -249,6 +249,52 @@ bool ConfigurationStack::tryGetPropertyAsString(const std::string& name, std::st
     return false;
 }
 
+ConfigurationBuilder::ConfigurationBuilder() :stack(new ConfigurationStack) {}
+
+ConfigurationBuilder& ConfigurationBuilder::push_env()
+{
+    Configuration::shared_pointer env(new ConfigurationEnviron);
+    stack->push_back(env);
+    return *this;
+}
+
+ConfigurationBuilder& ConfigurationBuilder::push_map()
+{
+    Configuration::shared_pointer env(new ConfigurationMap(mymap));
+    stack->push_back(env);
+    mymap.clear();
+    return *this;
+}
+
+ConfigurationBuilder&
+ConfigurationBuilder::push_config(const Configuration::shared_pointer& conf)
+{
+    stack->push_back(conf);
+    return *this;
+}
+
+ConfigurationBuilder&
+ConfigurationBuilder::_add(const std::string& name, const std::string& val)
+{
+    if(name.find_first_of(" \t\r\n")!=name.npos)
+        THROW_EXCEPTION2(std::invalid_argument, "Key name may not contain whitespace");
+    mymap[name] = val;
+    return *this;
+}
+
+Configuration::shared_pointer ConfigurationBuilder::build()
+{
+    if(!mymap.empty())
+        THROW_EXCEPTION2(std::logic_error, "Missing call to .push_map()");
+    if(stack->size()==0) {
+        return Configuration::shared_pointer(new ConfigurationMap); // empty map
+    } else if(stack->size()==1) {
+        return stack->pop_back();
+    } else {
+        return stack;
+    }
+}
+
 void ConfigurationProviderImpl::registerConfiguration(const string &name, Configuration::shared_pointer const & configuration)
 {
 	Lock guard(_mutex);
@@ -263,12 +309,15 @@ void ConfigurationProviderImpl::registerConfiguration(const string &name, Config
 
 Configuration::shared_pointer ConfigurationProviderImpl::getConfiguration(const string &name)
 {
-	std::map<std::string,Configuration::shared_pointer>::iterator configsIter = _configs.find(name);
+    Lock guard(_mutex);
+    std::map<std::string,Configuration::shared_pointer>::iterator configsIter = _configs.find(name);
 	if(configsIter != _configs.end())
 	{
 		return configsIter->second;
 	}
-	return Configuration::shared_pointer();
+    Configuration::shared_pointer env(new ConfigurationEnviron); // default to environment only
+    _configs[name] = env; // ensure that a later attempt to define this config will fail
+    return env;
 }
 
 ConfigurationProvider::shared_pointer configurationProvider;
@@ -280,8 +329,7 @@ ConfigurationProvider::shared_pointer ConfigurationFactory::getProvider()
 	if(configurationProvider.get() == NULL)
 	{
 		configurationProvider.reset(new ConfigurationProviderImpl());
-		// default
-		Configuration::shared_pointer systemConfig(new SystemConfigurationImpl());
+        Configuration::shared_pointer systemConfig(new ConfigurationEnviron);
 		configurationProvider->registerConfiguration("system", systemConfig);
 	}
 	return configurationProvider;

src/utils/configuration.h

@@ -155,6 +155,8 @@ class epicsShareClass ConfigurationMap: public Configuration
 public:
     typedef std::map<std::string, std::string> properties_t;
     properties_t properties;
+    ConfigurationMap() {}
+    ConfigurationMap(const properties_t& p) :properties(p) {}
 private:
     virtual bool tryGetPropertyAsString(const std::string& name, std::string* val) const;
 };
@@ -189,6 +191,27 @@ public:
     inline size_t size() const {return confs.size();}
 };
 
+struct ConfigurationBuilder
+{
+    ConfigurationBuilder();
+    ConfigurationBuilder& push_env();
+    ConfigurationBuilder& push_map();
+    ConfigurationBuilder& push_config(const Configuration::shared_pointer&);
+    template<typename V>
+    ConfigurationBuilder& add(const std::string& name, const V& val)
+    {
+        std::ostringstream strm;
+        strm<<val;
+        return _add(name, strm.str());
+    }
+    Configuration::shared_pointer build();
+private:
+    ConfigurationBuilder& _add(const std::string& name, const std::string& val);
+    ConfigurationMap::properties_t mymap;
+    std::tr1::shared_ptr<ConfigurationStack> stack;
+    friend ConfigurationBuilder& operator<<(ConfigurationBuilder&, const std::string& s);
+};
+
 /**
  * Configuration provider.
  */
@@ -249,6 +272,14 @@ public:
 	 * @return configuration provider
 	 */
 	static ConfigurationProvider::shared_pointer getProvider();
+    static void registerConfiguration(const std::string &name, Configuration::shared_pointer const & configuration)
+    {
+        getProvider()->registerConfiguration(name, configuration);
+    }
+    static Configuration::shared_pointer getConfiguration(const std::string& name)
+    {
+        return getProvider()->getConfiguration(name);
+    }
 
 private:
 	ConfigurationFactory() {};