Distinguish "strong" and "weak" target dependency edges

Utility dependencies are "strong" because they must be enforced to
generate a working build.  Link dependencies are "weak" because they can
be broken in the case of a static library cycle.

1 files changed, 20 insertions, 1 deletions

diff --git a/Source/cmGraphAdjacencyList.h b/Source/cmGraphAdjacencyList.h
index 41411c4..0149d33 100644
--- a/Source/cmGraphAdjacencyList.h
+++ b/Source/cmGraphAdjacencyList.h
@@ -14,7 +14,26 @@
 
 #include "cmStandardIncludes.h"
 
-struct cmGraphEdgeList: public std::vector<int> {};
+/**
+ * Graph edge representation.  Most use cases just need the
+ * destination vertex, so we support conversion to/from an int.  We
+ * also store boolean to indicate whether an edge is "strong".
+ */
+class cmGraphEdge
+{
+public:
+  cmGraphEdge(): Dest(0), Strong(true) {}
+  cmGraphEdge(int n): Dest(n), Strong(true) {}
+  cmGraphEdge(int n, bool s): Dest(n), Strong(s) {}
+  cmGraphEdge(cmGraphEdge const& r): Dest(r.Dest), Strong(r.Strong) {}
+  operator int() const { return this->Dest; }
+
+  bool IsStrong() const { return this->Strong; }
+private:
+  int Dest;
+  bool Strong;
+};
+struct cmGraphEdgeList: public std::vector<cmGraphEdge> {};
 struct cmGraphNodeList: public std::vector<int> {};
 struct cmGraphAdjacencyList: public std::vector<cmGraphEdgeList> {};