Implement a structural comparison operation on tier operations.

2 files changed, 13 insertions, 0 deletions

diff --git a/src/generic/problemresolver/tier_operation.cc b/src/generic/problemresolver/tier_operation.cc
index 8d8ac5fc..1b6e83ba 100644
--- a/src/generic/problemresolver/tier_operation.cc
+++ b/src/generic/problemresolver/tier_operation.cc
@@ -92,6 +92,15 @@ tier tier_operation::op_impl::apply(const tier &t) const
 	      out_user_levels.end());
 }
 
+int tier_operation::op_impl::compare(const op_impl &other) const
+{
+  const int structural_level_cmp = aptitude::util::compare3(structural_level, other.structural_level);
+  if(structural_level_cmp != 0)
+    return structural_level_cmp;
+  else
+    return aptitude::util::compare3(actions, other.actions);
+}
+
 void tier_operation::op_impl::dump(std::ostream &out) const
 {
   out << "(";
diff --git a/src/generic/problemresolver/tier_operation.h b/src/generic/problemresolver/tier_operation.h
index e3ae3759..47ca0029 100644
--- a/src/generic/problemresolver/tier_operation.h
+++ b/src/generic/problemresolver/tier_operation.h
@@ -144,6 +144,10 @@ class tier_operation
      */
     tier apply(const tier &t) const;
 
+    /** \brief Compare two operations by their identity.
+     */
+    int compare(const op_impl &other) const;
+
     /** \brief Dump this operation to a stream. */
     void dump(std::ostream &out) const;
   };