working version of the ParserStack class plus unit tests

5 files changed, 300 insertions, 169 deletions

diff --git a/src/core/parser/Parser.hpp b/src/core/parser/Parser.hpp
index b8faf98..fa5dd49 100644
--- a/src/core/parser/Parser.hpp
+++ b/src/core/parser/Parser.hpp
@@ -86,6 +86,19 @@ struct ParserContext {
 	    : scope(scope), registry(registry), logger(logger){};
 };
 
+struct StandaloneParserContext : public ParserContext {
+private:
+	Logger logger;
+	Scope scope;
+	Registry registry;
+
+public:
+	StandaloneParserContext()
+	    : ParserContext(scope, registry, logger),
+	      scope(nullptr),
+	      registry(logger){};
+};
+
 /**
  * Abstract parser class. This class builds the basic interface that should be
  * used by any parser which reads data from an input stream and transforms it
diff --git a/src/core/parser/ParserStack.cpp b/src/core/parser/ParserStack.cpp
new file mode 100644
index 0000000..01fce3f
--- /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);
+}
+}
+}
+
diff --git a/src/core/parser/XmlStates.hpp b/src/core/parser/ParserStack.hpp
index 70e95f4..a777b1e 100644
--- a/src/core/parser/XmlStates.hpp
+++ b/src/core/parser/ParserStack.hpp
@@ -16,53 +16,39 @@
     along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
 
-#ifndef _OUSIA_XML_STATES_HPP_
-#define _OUSIA_XML_STATES_HPP_
+/**
+ * @file ParserStack.hpp
+ *
+ * Helper classes for document or description parsers. Contains the ParserStack
+ * class, which is an pushdown automaton responsible for accepting commands in
+ * the correct order and calling specified handlers.
+ *
+ * @author Andreas Stöckel (astoecke@techfak.uni-bielefeld.de)
+ */
+
+#ifndef _OUSIA_PARSER_STACK_HPP_
+#define _OUSIA_PARSER_STACK_HPP_
 
 #include <cstdint>
 
 #include <map>
+#include <memory>
 #include <set>
 #include <stack>
 #include <vector>
 
+#include "Parser.hpp"
+
 namespace ousia {
 namespace parser {
 
-class Scope;
-class Registry;
-class Logger;
-
-namespace xml {
-
 /**
- * The State class represents all states the XML parser can be in. These states
- * mostly represent single tags.
+ * The State type alias is used to
  */
-enum class State : uint8_t {
-	/* Meta states */
-	ALL = -1,
-
-	/* Start state */
-	NONE,
-
-	/* Special commands */
-	INCLUDE,
-	INLINE,
+using State = int8_t;
 
-	/* Document states */
-	DOCUMENT,
-	HEAD,
-	BODY,
-
-	/* Domain description states */
-	DOMAIN,
-
-	/* Type system states */
-	TYPESYSTEM,
-	TYPE,
-	TYPE_ELEM
-};
+static const State STATE_ALL = -2;
+static const State STATE_NONE = -1;
 
 /**
  * The handler class provides a context for handling an XML tag. It has to be
@@ -125,7 +111,7 @@ public:
 	/**
 	 * Virtual destructor.
 	 */
-	virtual ~Handler();
+	virtual ~Handler(){};
 
 	/**
 	 * Returns the node instance that was created by the handler.
@@ -158,14 +144,14 @@ public:
 	 * @param data is a pointer at the character data that is available for the
 	 * Handler instance.
 	 */
-	virtual void data(char *data, int len){};
+	virtual void data(const char *data, int len){};
 
 	/**
 	 * Called whenever a direct child element was created and has ended.
 	 *
 	 * @param handler is a reference at the child Handler instance.
 	 */
-	virtual void child(Handler *handler){};
+	virtual void child(std::shared_ptr<Handler> handler){};
 };
 
 /**
@@ -176,95 +162,90 @@ using HandlerConstructor = Handler *(*)(const ParserContext &ctx,
                                         std::string name, State state,
                                         State parentState, bool isChild);
 
+struct HandlerDescriptor;
+
 /**
- * The StateStack class is a pushdown automaton responsible for turning a
- * command stream into a tree of Node instances.
+ * Used internlly by StateStack to store Handler instances and parameters
+ * from HandlerDescriptor that are not stored in the Handler instance
+ * itself. Instances of the HandlerInstance class can be created using the
+ * HandlerDescriptor "create" method.
  */
-class StateStack {
-public:
+struct HandlerInstance {
 	/**
-	 * Used internlly by StateStack to store Handler instances and parameters
-	 * from HandlerDescriptor that are not stored in the Handler instance
-	 * itself. Instances of the HandlerInstance class can be created using the
-	 * HandlerDescriptor "create" method.
+	 * Pointer at the actual handler instance.
 	 */
-	struct HandlerInstance {
-		/**
-		 * Pointer at the actual handler instance.
-		 */
-		std::unique_ptr<Handler> handler;
-
-		/**
-		 * Value of the arbitraryChildren flag stored in the HandlerDescriptor
-		 * class.
-		 */
-		const bool arbitraryChildren;
-
-		HandlerInstance(std::unique_ptr<Handler> handler,
-		                bool arbitraryChildren)
-		    : handler(handler), arbitraryChildren(arbitraryChildren)
-		{
-		}
+	std::shared_ptr<Handler> handler;
+
+	const HandlerDescriptor *descr;
+
+	HandlerInstance(Handler *handler, const HandlerDescriptor *descr)
+	    : handler(handler), descr(descr)
+	{
 	}
+};
 
+/**
+ * Used internally by StateStack to store the pushdown automaton
+ * description.
+ */
+struct HandlerDescriptor {
 	/**
-	 * Used internally by StateStack to store the pushdown automaton
-	 * description.
+	 * The valid parent states.
 	 */
-	struct HandlerDescriptor {
-		/**
-		 * The valid parent states.
-		 */
-		const std::set<State> parentStates;
-
-		/**
-		 * Pointer at a function which creates a new concrete Handler instance.
-		 */
-		const HandlerConstructor ctor;
-
-		/**
-		 * The target state for the registered handler.
-		 */
-		const State targetState;
-
-		/**
-		 * Set to true if this handler instance allows arbitrary children as
-		 * tags.
-		 */
-		const bool arbitraryChildren;
-
-		HandlerDescriptor(std::set<State> parentStates, HandlerConstructor ctor,
-		                  State targetState, bool arbitraryChildren = false)
-		    : parentStates(std::move(parentStates)),
-		      ctor(constructor),
-		      targetState(targetState),
-		      arbitraryChildren(arbitraryChildren)
-		{
-		}
-
-		HandlerInstance create(const ParserContext &ctx, std::string name,
-		                       State parentState, bool isChild)
-		{
-			return HandlerInstance{
-			    ctor(ctx, name, targetState, parentState, isChild),
-			    arbitraryChildren};
-		}
-	};
+	const std::set<State> parentStates;
 
-private:
 	/**
-	 * Map containing all registered command names and the corresponding
-	 * handler
-	 * descriptor.
+	 * Pointer at a function which creates a new concrete Handler instance.
+	 */
+	const HandlerConstructor ctor;
+
+	/**
+	 * The target state for the registered handler.
+	 */
+	const State targetState;
+
+	/**
+	 * Set to true if this handler instance allows arbitrary children as
+	 * tags.
 	 */
-	const std::multimap<std::string, HandlerDescriptor> handlers;
+	const bool arbitraryChildren;
+
+	HandlerDescriptor(std::set<State> parentStates, HandlerConstructor ctor,
+	                  State targetState, bool arbitraryChildren = false)
+	    : parentStates(std::move(parentStates)),
+	      ctor(ctor),
+	      targetState(targetState),
+	      arbitraryChildren(arbitraryChildren)
+	{
+	}
 
 	/**
+	 * Creates an instance of the concrete Handler class represented by the
+	 * HandlerDescriptor and calls its start function.
+	 */
+	HandlerInstance create(const ParserContext &ctx, std::string name,
+	                       State parentState, bool isChild, char **attrs) const;
+};
+
+/**
+ * The ParserStack class is a pushdown automaton responsible for turning a
+ * command stream into a tree of Node instances.
+ */
+class ParserStack {
+private:
+	/**
 	 * Reference at the parser context.
 	 */
 	const ParserContext &ctx;
 
 	/**
+	 * Map containing all registered command names and the corresponding
+	 * handler
+	 * descriptor.
+	 */
+	const std::multimap<std::string, HandlerDescriptor> &handlers;
+
+	/**
 	 * Internal stack used for managing the currently active Handler instances.
 	 */
 	std::stack<HandlerInstance> stack;
@@ -281,21 +262,54 @@ private:
 
 public:
 	/**
-	 * Creates a new instance of the StateStack class.
+	 * Creates a new instance of the ParserStack class.
 	 *
 	 * @param handlers is a map containing the command names and the
 	 * corresponding HandlerDescriptor instances.
 	 */
-	StateStack(const ParserContext &ctx,
-	           std::multimap<std::string, HandlerDescriptor> handlers)
-	    : handlers(std::move(handlers)),
-	      ctx(ctx),
-	      currentState(State::NONE),
-	      arbitraryChildren(false);
+	ParserStack(const ParserContext &ctx,
+	            const std::multimap<std::string, HandlerDescriptor> &handlers)
+	    : ctx(ctx), handlers(handlers){};
+
+	/**
+	 * Returns the state the ParserStack instance currently is in.
+	 *
+	 * @return the state of the currently active Handler instance or STATE_NONE
+	 * if no handler is on the stack.
+	 */
+	State currentState() {
+		return stack.empty() ? STATE_NONE : stack.top().handler->state;
+	}
+
+	/**
+	 * Returns the command name that is currently being handled.
+	 *
+	 * @return the name of the command currently being handled by the active
+	 * Handler instance or an empty string if no handler is currently active.
+	 */
+	std::string currentName() {
+		return stack.empty() ? std::string{} : stack.top().handler->name;
+	}
+
+	/**
+	 * Returns whether the current command handler allows arbitrary children.
+	 *
+	 * @return true if the handler allows arbitrary children, false otherwise.
+	 */
+	bool currentArbitraryChildren() {
+		return stack.empty() ? false : stack.top().descr->arbitraryChildren;
+	}
+
+	// TODO: Change signature
+	void start(std::string name, char **attrs);
+
+	void end();
+
+	// TODO: Change signature
+	void data(const char *data, int len);
 };
 }
 }
-}
 
-#endif /* _OUSIA_XML_STATES_HPP_ */
+#endif /* _OUSIA_PARSER_STACK_HPP_ */
 
diff --git a/src/core/parser/Scope.hpp b/src/core/parser/Scope.hpp
index 0c37fbd..9c5504f 100644
--- a/src/core/parser/Scope.hpp
+++ b/src/core/parser/Scope.hpp
@@ -19,6 +19,8 @@
 #ifndef _OUSIA_PARSER_SCOPE_H_
 #define _OUSIA_PARSER_SCOPE_H_
 
+#include <deque>
+
 #include <core/Node.hpp>
 
 /**
diff --git a/src/core/parser/XmlStates.cpp b/src/core/parser/XmlStates.cpp
deleted file mode 100644
index ec0f002..0000000
--- a/src/core/parser/XmlStates.cpp
+++ /dev/null
@@ -1,53 +0,0 @@
-/*
-    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 "XmlStates.hpp"
-
-namespace ousia {
-namespace parser {
-namespace xml {
-
-std::set<std::string> StateStack::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 StateStack::start(std::string tagName, char **attrs) {
-	// Fetch the current handler and the current state
-	const Handler *h = stack.empty() ? nullptr : stack.top();
-	const State currentState = h ? State::NONE : h->state;
-
-	// Fetch all handlers for the given tagName
-	auto range = handlers.equal_range(tagName);
-	if (range->first == handlers.end()) {
-		// There are no handlers registered for this tag name -- check whether
-		// the current handler supports arbitrary children
-		if (h && h->arbitraryChildren)
-	}
-}
-
-}
-}
-}
-