1 files changed, 74 insertions, 0 deletions
diff --git a/project2/common/variables/lookup.cpp b/project2/common/variables/lookup.cpp
new file mode 100644
index 0000000..892968e
--- /dev/null
+++ b/project2/common/variables/lookup.cpp
@@ -0,0 +1,74 @@
+#include <pch.hpp>
+#include "../variables.h"
+#include "../safeMapFind.h"
+#include "../logger.h"
+#include "../rowProcessor.h"
+#include "../rowSet.h"
+#include <boost/foreach.hpp>
+#include "../scriptLoader.h"
+#include "../scriptStorage.h"
+
+
+/// Variable implementation that looks up it's value in a map of key(s)/value pairs
+class VariableLookup : public VariableImplDyn, public RowProcessor {
+	private:
+		typedef std::vector<VariableType> Key;
+		typedef std::map<Key, VariableType> Map;
+	public:
+		class NotFound : public std::runtime_error {
+			public:
+				NotFound(const Key & k) :
+					std::runtime_error(mklist(k)) {
+				}
+				static std::string mklist(const Key & k) {
+					std::string l("(");
+					for (Key::const_iterator kp = k.begin(); kp != k.end(); ++kp) {
+						if (kp != k.begin()) l += ", ";
+						l += kp->operator const std::string &();
+					}
+					l += ")";
+					return l;
+				}
+		};
+		VariableLookup(ScriptNodePtr e) :
+			VariableImplDyn(e),
+			RowProcessor(e),
+			name(e->value("name").as<Glib::ustring>())
+		{
+			e->script->loader.addLoadTarget(e, Storer::into<ElementLoader>(&rowSets));
+		}
+		VariableType value() const
+		{
+			if (map.empty()) {
+				fillCache();
+			}
+			Key k;
+			k.reserve(parameters.size());
+			BOOST_FOREACH(const Parameters::value_type & p, parameters) {
+				k.push_back(p.second);
+			}
+			return safeMapLookup<NotFound>(map, k);
+		}
+	private:
+		void fillCache() const
+		{
+			BOOST_FOREACH(const RowSets::value_type & rs, rowSets) {
+				rs->execute(filter, this);
+			}
+			Logger()->messagef(LOG_DEBUG, "%s: %s has filled cached with %zu items",
+					__PRETTY_FUNCTION__, name.c_str(), map.size());
+		}
+		void rowReady(const RowState * rs) const
+		{
+			Key k;
+			BOOST_FOREACH(const Parameters::value_type & p, parameters) {
+				k.push_back(rs->getCurrentValue(p.first));
+			}
+			map[k] = rs->getCurrentValue(name);
+		}
+		mutable Map map;
+		typedef ANONSTORAGEOF(RowSet) RowSets;
+		RowSets rowSets;
+		const Glib::ustring name;
+};
+DECLARE_COMPONENT_LOADER("lookup", VariableLookup, VariableLoader);