/indra/llcommon/lldependencies.cpp
C++ | 103 lines | 40 code | 4 blank | 59 comment | 0 complexity | 797b9b66682a8313bb65b7e9a2a96e9d MD5 | raw file
Possible License(s): LGPL-2.1
- /**
- * @file lldependencies.cpp
- * @author Nat Goodspeed
- * @date 2008-09-17
- * @brief Implementation for lldependencies.
- *
- * $LicenseInfo:firstyear=2008&license=viewerlgpl$
- * Second Life Viewer Source Code
- * Copyright (C) 2010, Linden Research, Inc.
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation;
- * version 2.1 of the License only.
- *
- * This library 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
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
- *
- * Linden Research, Inc., 945 Battery Street, San Francisco, CA 94111 USA
- * $/LicenseInfo$
- */
- // Precompiled header
- #include "linden_common.h"
- // associated header
- #include "lldependencies.h"
- // STL headers
- #include <map>
- #include <sstream>
- // std headers
- // external library headers
- #include <boost/graph/graph_traits.hpp> // for boost::graph_traits
- #include <boost/graph/adjacency_list.hpp>
- #include <boost/graph/topological_sort.hpp>
- #include <boost/graph/exception.hpp>
- // other Linden headers
- LLDependenciesBase::VertexList LLDependenciesBase::topo_sort(int vertices, const EdgeList& edges) const
- {
- // Construct a Boost Graph Library graph according to the constraints
- // we've collected. It seems as though we ought to be able to capture
- // the uniqueness of vertex keys using a setS of vertices with a
- // string property -- but I don't yet understand adjacency_list well
- // enough to get there. All the examples I've seen so far use integers
- // for vertices.
- // Define the Graph type. Use a vector for vertices so we can use the
- // default topological_sort vertex lookup by int index. Use a set for
- // edges because the same dependency may be stated twice: Node "a" may
- // specify that it must precede "b", while "b" may also state that it
- // must follow "a".
- typedef boost::adjacency_list<boost::setS, boost::vecS, boost::directedS,
- boost::no_property> Graph;
- // Instantiate the graph. Without vertex properties, we need say no
- // more about vertices than the total number.
- Graph g(edges.begin(), edges.end(), vertices);
- // topo sort
- typedef boost::graph_traits<Graph>::vertex_descriptor VertexDesc;
- typedef std::vector<VertexDesc> SortedList;
- SortedList sorted;
- // note that it throws not_a_dag if it finds a cycle
- try
- {
- boost::topological_sort(g, std::back_inserter(sorted));
- }
- catch (const boost::not_a_dag& e)
- {
- // translate to the exception we define
- std::ostringstream out;
- out << "LLDependencies cycle: " << e.what() << '\n';
- // Omit independent nodes: display only those that might contribute to
- // the cycle.
- describe(out, false);
- throw Cycle(out.str());
- }
- // A peculiarity of boost::topological_sort() is that it emits results in
- // REVERSE topological order: to get the result you want, you must
- // traverse the SortedList using reverse iterators.
- return VertexList(sorted.rbegin(), sorted.rend());
- }
- std::ostream& LLDependenciesBase::describe(std::ostream& out, bool full) const
- {
- // Should never encounter this base-class implementation; may mean that
- // the KEY type doesn't have a suitable ostream operator<<().
- out << "<no description available>";
- return out;
- }
- std::string LLDependenciesBase::describe(bool full) const
- {
- // Just use the ostream-based describe() on a std::ostringstream. The
- // implementation is here mostly so that we can avoid #include <sstream>
- // in the header file.
- std::ostringstream out;
- describe(out, full);
- return out.str();
- }