1 files changed, 101 insertions, 0 deletions
diff --git a/src/rebar_digraph.erl b/src/rebar_digraph.erl
new file mode 100644
index 0000000..decc542
--- /dev/null
+++ b/src/rebar_digraph.erl
@@ -0,0 +1,101 @@
+-module(rebar_digraph).
+
+-export([check_graph/2
+        ,restore_graph/1
+        ,store_graph/3
+        ,solve/2
+        ,subgraph/2]).
+
+-include("rebar.hrl").
+
+check_graph(_File, #graph{vsn=?GRAPH_VSN}) ->
+    ok;
+check_graph(File, #graph{vsn=Vsn}) ->
+    ?ABORT("~s file version is incompatible. expected: ~b got: ~b",
+           [File, ?GRAPH_VSN, Vsn]);
+check_graph(File, _) ->
+    ?ABORT("~s file is invalid. Please delete before next run.",
+           [File]).
+
+restore_graph({Vs, Es}) ->
+    G = digraph:new(),
+    lists:foreach(fun({V, LastUpdated}) ->
+                          digraph:add_vertex(G, V, LastUpdated)
+                  end, Vs),
+    lists:foreach(fun({V1, V2}) ->
+                          digraph:add_edge(G, V1, V2)
+                  end, Es),
+    G;
+restore_graph(File) ->
+    G = digraph:new(),
+    case file:read_file(File) of
+        {ok, Data} ->
+            try binary_to_term(Data) of
+                G ->
+                    %% ok = check_erlcinfo(Config, Graph),
+                    #graph{info=Graph} = G,
+                    {Vs, Es} = Graph,
+                    lists:foreach(
+                      fun({V, LastUpdated}) ->
+                              digraph:add_vertex(G, V, LastUpdated)
+                      end, Vs),
+                    lists:foreach(
+                      fun({V1, V2}) ->
+                              digraph:add_edge(G, V1, V2)
+                      end, Es)
+            catch
+                error:badarg ->
+                    ?ERROR(
+                       "Failed (binary_to_term) to restore rebar info file."
+                       " Discard file.", []),
+                    ok
+            end;
+        _Err ->
+            ok
+    end,
+    G.
+
+store_graph(_G, _File, _Modified = false) ->
+    ok;
+store_graph(G, File, _Modified) ->
+    Vs = lists:map(
+           fun(V) ->
+                   digraph:vertex(G, V)
+           end, digraph:vertices(G)),
+    Es = lists:flatmap(
+           fun({V, _}) ->
+                   lists:map(
+                     fun(E) ->
+                             {_, V1, V2, _} = digraph:edge(G, E),
+                             {V1, V2}
+                     end, digraph:out_edges(G, V))
+           end, Vs),
+
+    ok = filelib:ensure_dir(File),
+    Data = term_to_binary(#graph{info={Vs, Es}}, [{compressed, 9}]),
+    file:write_file(File, Data).
+
+solve(Graph, Vertices) ->
+    solve(Graph, Vertices, dict:new()).
+
+solve(_Graph, [], Solution) ->
+    {_, Vertices} = lists:unzip(dict:to_list(Solution)),
+    Vertices;
+solve(Graph, Vertices, Solution) ->
+    {NV, NS} =
+        lists:foldl(fun(V, {NewVertices, SolutionAcc}) ->
+                        OutNeighbors = digraph:out_neighbours(Graph, V),
+                        lists:foldl(fun({Key, _}=N, {NewVertices1, SolutionAcc1}) ->
+                                            case dict:is_key(Key, SolutionAcc1) orelse
+                                                lists:keymember(Key, 1, Vertices) of
+                                                true ->
+                                                    {NewVertices1, SolutionAcc1};
+                                                false ->
+                                                    {[N | NewVertices1], dict:store(Key, N, SolutionAcc1)}
+                                            end
+                                    end, {NewVertices, SolutionAcc}, OutNeighbors)
+                    end, {[], Solution}, Vertices),
+    solve(Graph, NV, NS).
+
+subgraph(Graph, Vertices) ->
+    digraph_utils:subgraph(Graph, Vertices).