1 files changed, 155 insertions, 0 deletions
diff --git a/src/core/parser/ParserStack.cpp b/src/core/parser/ParserStack.cpp
new file mode 100644
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--- /dev/null
+++ b/src/core/parser/ParserStack.cpp
@@ -0,0 +1,155 @@
+/*
+    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 "ParserStack.hpp"
+
+#include <core/Exceptions.hpp>
+
+namespace ousia {
+namespace parser {
+
+/* Class HandlerDescriptor */
+
+HandlerInstance HandlerDescriptor::create(const ParserContext &ctx,
+                                          std::string name, State parentState,
+                                          bool isChild, char **attrs) const
+{
+	Handler *h = ctor(ctx, name, targetState, parentState, isChild);
+	h->start(attrs);
+	return HandlerInstance(h, this);
+}
+
+/* Class ParserStack */
+
+/**
+ * Function used internally to turn the elements of a collection into a string
+ * separated by the given delimiter.
+ */
+template <class T>
+static std::string join(T es, const std::string &delim)
+{
+	std::stringstream res;
+	bool first = true;
+	for (auto &e : es) {
+		if (!first) {
+			res << delim;
+		}
+		res << e;
+		first = false;
+	}
+	return res.str();
+}
+
+/**
+ * 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 \""}) +
+		    join(expected, "\", \"") + std::string{"\", but got \""} + name +
+		    std::string{"\""}};
+	}
+}
+
+std::set<std::string> ParserStack::expectedCommands(State state)
+{
+	std::set<std::string> res;
+	for (const auto &v : handlers) {
+		if (v.second.parentStates.count(state)) {
+			res.insert(v.first);
+		}
+	}
+	return res;
+}
+
+void ParserStack::start(std::string name, char **attrs)
+{
+	// Fetch the current handler and the current state
+	const HandlerInstance *h = stack.empty() ? nullptr : &stack.top();
+	const State curState = currentState();
+	bool isChild = false;
+
+	// Fetch the correct Handler descriptor for this
+	const HandlerDescriptor *descr = nullptr;
+	auto range = handlers.equal_range(name);
+	for (auto it = range.first; it != range.second; it++) {
+		if (it->second.parentStates.count(curState)) {
+			descr = &(it->second);
+			break;
+		}
+	}
+	if (!descr && currentArbitraryChildren()) {
+		isChild = true;
+		descr = h->descr;
+	}
+
+	// No descriptor found, throw an exception.
+	if (!descr) {
+		throw invalidCommand(name, expectedCommands(curState));
+	}
+
+	// Instantiate the handler and call its start function
+	stack.emplace(descr->create(ctx, name, curState, isChild, attrs));
+}
+
+void ParserStack::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
+	HandlerInstance inst{stack.top()};
+	stack.pop();
+
+	// Call the end function of the last Handler
+	inst.handler->end();
+
+	// Call the "child" function of the parent Handler in the stack
+	// (if one exists).
+	if (!stack.empty()) {
+		stack.top().handler->child(inst.handler);
+	}
+}
+
+void ParserStack::data(const char *data, int len)
+{
+	// 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().handler->data(data, len);
+}
+}
+}
+