From: Mikko Rasa <tdb@tdb.fi>
Date: Thu, 17 Jan 2013 10:48:58 +0000 (+0200)
Subject: Use a dedicated exception class for route errors
X-Git-Url: http://git.tdb.fi/?a=commitdiff_plain;h=a20b8421d002629a9f4d97c0c378e9f9cb29e292;p=r2c2.git

Use a dedicated exception class for route errors
---

diff --git a/source/libr2c2/route.cpp b/source/libr2c2/route.cpp
index 78f96a6..aabe880 100644
--- a/source/libr2c2/route.cpp
+++ b/source/libr2c2/route.cpp
@@ -1,6 +1,7 @@
 #include <queue>
 #include <msp/core/maputils.h>
 #include <msp/strings/format.h>
+#include <msp/strings/utils.h>
 #include "layout.h"
 #include "route.h"
 #include "track.h"
@@ -127,6 +128,20 @@ Route *create_route(const TrackIter &from, const Pred &goal)
 
 namespace R2C2 {
 
+string bad_route::get_message(RouteValidityMask valid)
+{
+	const char *reasons[3];
+	unsigned i = 0;
+	if(!(valid&1))
+		reasons[i++] = "unlinked";
+	else if(!(valid&2))
+		reasons[i++] = "branching";
+	else if(!(valid&4))
+		reasons[i++] = "not smooth";
+	return join(reasons, reasons+i, ", ");
+}
+
+
 Route::Route(Layout &l):
 	layout(l),
 	temporary(false)
@@ -241,13 +256,9 @@ void Route::add_track(Track &trk)
 
 	if(!tracks.empty())
 	{
-		unsigned valid = check_validity(trk);
-		if(!(valid&1))
-			throw Exception("Not linked to existing tracks");
-		else if(!(valid&2))
-			throw Exception("Branching routes not allowed");
-		else if(!(valid&4))
-			throw Exception("Route must be smooth");
+		RouteValidityMask valid = check_validity(trk);
+		if(valid!=ROUTE_VALID)
+			throw bad_route(valid);
 	}
 
 	tracks.insert(&trk);
@@ -263,18 +274,17 @@ void Route::add_tracks(const set<Track *> &trks)
 
 	while(!pending.empty())
 	{
-		bool found = false;
+		RouteValidityMask valid = ROUTE_INVALID;
 		for(set<Track *>::const_iterator i=pending.begin(); i!=pending.end(); ++i)
-			if(tracks.empty() || check_validity(**i)==7)
+			if(tracks.empty() || (valid=check_validity(**i))==ROUTE_VALID)
 			{
 				tracks.insert(*i);
 				pending.erase(*i);
-				found = true;
 				break;
 			}
 
-		if(!found)
-			throw Exception("Could not add all tracks to route");
+		if(valid!=ROUTE_VALID)
+			throw bad_route(valid);
 	}
 
 	update_turnouts();
@@ -319,9 +329,9 @@ void Route::save(list<DataFile::Statement> &st) const
 		st.push_back((DataFile::Statement("turnout"), i->first, i->second));
 }
 
-unsigned Route::check_validity(Track &trk) const
+RouteValidityMask Route::check_validity(Track &trk) const
 {
-	unsigned result = 4;
+	unsigned result = ROUTE_SMOOTH;
 	const vector<Track *> &links = trk.get_links();
 	for(vector<Track *>::const_iterator i=links.begin(); i!=links.end(); ++i)
 	{
@@ -331,7 +341,7 @@ unsigned Route::check_validity(Track &trk) const
 			continue;
 
 		// Linked to an existing track - good
-		result |= 1;
+		result |= ROUTE_LINKED;
 
 		if(unsigned tid = (*i)->get_turnout_id())
 		{
@@ -341,7 +351,7 @@ unsigned Route::check_validity(Track &trk) const
 			{
 				// Linking to a turnout with path set is only good if we're continuing that path
 				if(ep.paths&(1<<path))
-					result |= 2;
+					result |= ROUTE_LINEAR;
 			}
 			else
 			{
@@ -366,20 +376,20 @@ unsigned Route::check_validity(Track &trk) const
 						const TrackType::Endpoint &ep2 = (*i)->get_type().get_endpoint(j);
 						if(!(ep.paths&ep2.paths))
 							// Impossible path through the turnout - not good
-							result &= 3;
+							result &= ~ROUTE_SMOOTH;
 					}
 
 				// Only good if at most one other track is linked to the turnout
 				if(count<=1)
-					result |= 2;
+					result |= ROUTE_LINEAR;
 			}
 		}
 		else
 			// Linked to something linear - good
-			result |= 2;
+			result |= ROUTE_LINEAR;
 	}
 
-	return result;
+	return static_cast<RouteValidityMask>(result);
 }
 
 void Route::track_removed(Track &t)
diff --git a/source/libr2c2/route.h b/source/libr2c2/route.h
index 4f5d056..5ea86be 100644
--- a/source/libr2c2/route.h
+++ b/source/libr2c2/route.h
@@ -14,6 +14,26 @@ class Track;
 class TrackIter;
 class Zone;
 
+enum RouteValidityMask
+{
+	ROUTE_INVALID = 0,
+	ROUTE_LINKED = 1,
+	ROUTE_LINEAR = 2,
+	ROUTE_SMOOTH = 4,
+	ROUTE_VALID = 7
+};
+
+class bad_route: public std::logic_error
+{
+public:
+	bad_route(RouteValidityMask m): std::logic_error(get_message(m)) { }
+	virtual ~bad_route() throw() { }
+
+private:
+	static std::string get_message(RouteValidityMask);
+};
+
+
 class Route: public sigc::trackable
 {
 public:
@@ -60,7 +80,7 @@ public:
 	bool has_track(Track &) const;
 	void save(std::list<Msp::DataFile::Statement> &) const;
 private:
-	unsigned check_validity(Track &) const;
+	RouteValidityMask check_validity(Track &) const;
 	void track_removed(Track &);
 
 public: