1 files changed, 188 insertions, 0 deletions
diff --git a/src/core/parser/stack/Stack.cpp b/src/core/parser/stack/Stack.cpp
new file mode 100644
index 0000000..1d83a68
--- /dev/null
+++ b/src/core/parser/stack/Stack.cpp
@@ -0,0 +1,188 @@
+/*
+    Ousía
+    Copyright (C) 2014, 2015  Benjamin Paaßen, Andreas Stöckel
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include <sstream>
+
+#include <core/common/Utils.hpp>
+#include <core/common/Exceptions.hpp>
+#include <core/parser/ParserScope.hpp>
+
+#include "Stack.hpp"
+
+namespace ousia {
+namespace parser_stack {
+
+/* Class StateStack */
+
+/**
+ * Returns an Exception that should be thrown when a currently invalid command
+ * is thrown.
+ */
+static LoggableException InvalidCommand(const std::string &name,
+                                        const std::set<std::string> &expected)
+{
+	if (expected.empty()) {
+		return LoggableException{
+		    std::string{"No nested elements allowed, but got \""} + name +
+		    std::string{"\""}};
+	} else {
+		return LoggableException{
+		    std::string{"Expected "} +
+		    (expected.size() == 1 ? std::string{"\""}
+		                          : std::string{"one of \""}) +
+		    Utils::join(expected, "\", \"") + std::string{"\", but got \""} +
+		    name + std::string{"\""}};
+	}
+}
+
+StateStack::StateStack(
+    ParserContext &ctx,
+    const std::multimap<std::string, const State *> &states)
+    : ctx(ctx), states(states)
+{
+}
+
+bool StateStack::deduceState()
+{
+	// Assemble all states
+	std::vector<const State *> states;
+	for (const auto &e : this->states) {
+		states.push_back(e.second);
+	}
+
+	// Fetch the type signature of the scope and derive all possible states,
+	// abort if no unique parser state was found
+	std::vector<const State *> possibleStates =
+	    StateDeductor(ctx.getScope().getStackTypeSignature(), states)
+	        .deduce();
+	if (possibleStates.size() != 1) {
+		ctx.getLogger().error(
+		    "Error while including file: Cannot deduce parser state.");
+		return false;
+	}
+
+	// Switch to this state by creating a dummy handler
+	const State *state = possibleStates[0];
+	Handler *handler =
+	    DefaultHandler::create({ctx, "", *state, *state, SourceLocation{}});
+	stack.emplace(handler);
+	return true;
+}
+
+std::set<std::string> StateStack::expectedCommands()
+{
+	const State *currentState = &(this->currentState());
+	std::set<std::string> res;
+	for (const auto &v : states) {
+		if (v.second->parents.count(currentState)) {
+			res.insert(v.first);
+		}
+	}
+	return res;
+}
+
+const State &StateStack::currentState()
+{
+	return stack.empty() ? States::None : stack.top()->state();
+}
+
+std::string StateStack::currentCommandName()
+{
+	return stack.empty() ? std::string{} : stack.top()->name();
+}
+
+const State *StateStack::findTargetState(const std::string &name)
+{
+	const State *currentState = &(this->currentState());
+	auto range = states.equal_range(name);
+	for (auto it = range.first; it != range.second; it++) {
+		const StateSet &parents = it->second->parents;
+		if (parents.count(currentState) || parents.count(&States::All)) {
+			return it->second;
+		}
+	}
+
+	return nullptr;
+}
+
+void StateStack::start(const std::string &name, Variant::mapType &args,
+                        const SourceLocation &location)
+{
+	State const *targetState = findTargetState(name);
+// TODO: Andreas, please improve this.
+//	if (!Utils::isIdentifier(name)) {
+//		throw LoggableException(std::string("Invalid identifier \"") + name +
+//		                        std::string("\""));
+//	}
+
+	if (targetState == nullptr) {
+		targetState = findTargetState("*");
+	}
+	if (targetState == nullptr) {
+		throw InvalidCommand(name, expectedCommands());
+	}
+
+	// Fetch the associated constructor
+	HandlerConstructor ctor = targetState->elementHandler
+	                              ? targetState->elementHandler
+	                              : DefaultHandler::create;
+
+	// Canonicalize the arguments, allow additional arguments
+	targetState->arguments.validateMap(args, ctx.getLogger(), true);
+
+	// Instantiate the handler and call its start function
+	Handler *handler = ctor({ctx, name, *targetState, currentState(), location});
+	handler->start(args);
+	stack.emplace(handler);
+}
+
+void StateStack::start(std::string name, const Variant::mapType &args,
+                        const SourceLocation &location)
+{
+	Variant::mapType argsCopy(args);
+	start(name, argsCopy);
+}
+
+void StateStack::end()
+{
+	// Check whether the current command could be ended
+	if (stack.empty()) {
+		throw LoggableException{"No command to end."};
+	}
+
+	// Remove the current HandlerInstance from the stack
+	std::shared_ptr<Handler> inst{stack.top()};
+	stack.pop();
+
+	// Call the end function of the last Handler
+	inst->end();
+}
+
+void StateStack::data(const std::string &data, int field)
+{
+	// Check whether there is any command the data can be sent to
+	if (stack.empty()) {
+		throw LoggableException{"No command to receive data."};
+	}
+
+	// Pass the data to the current Handler instance
+	stack.top()->data(data, field);
+}
+}
+}
+