Allow overriding apply(match_extra) version in cxx_rule_v1

2 files changed, 29 insertions, 5 deletions

diff --git a/libbuild2/adhoc-rule-cxx.cxx b/libbuild2/adhoc-rule-cxx.cxx
index 637f9af..2ac97eb 100644
--- a/libbuild2/adhoc-rule-cxx.cxx
+++ b/libbuild2/adhoc-rule-cxx.cxx
@@ -25,6 +25,13 @@ namespace build2
     return true;
   }
 
+  recipe cxx_rule_v1::
+  apply (action, target&) const
+  {
+    assert (false); // This (or the match_extra version) must be overriden.
+    return empty_recipe;
+  }
+
   // adhoc_cxx_rule
   //
   adhoc_cxx_rule::
@@ -699,6 +706,13 @@ namespace build2
       return group_recipe; // Execute the group's recipe.
     }
 
+    // Note that while we probably could call pattern's apply_group_members()
+    // here, apply_group_prerequisites() is normally called after adding
+    // prerequisites but before matching, which can only be done from the
+    // rule's implementation. Also, for apply_group_members(), there is the
+    // explicit group special case which may also require custom logic.
+    // So it feels best to leave both to the implementation.
+
     return impl.load (memory_order_relaxed)->apply (a, t, me);
   }
 
diff --git a/libbuild2/adhoc-rule-cxx.hxx b/libbuild2/adhoc-rule-cxx.hxx
index 89bc05f..2ac2281 100644
--- a/libbuild2/adhoc-rule-cxx.hxx
+++ b/libbuild2/adhoc-rule-cxx.hxx
@@ -36,11 +36,6 @@ namespace build2
     // cannot be injected as a real prerequisite since it's from a different
     // build context).
     //
-    // If pattern is not NULL then this recipe belongs to an ad hoc pattern
-    // rule and apply() may need to call the pattern's apply_*() functions if
-    // the pattern has any ad hoc group member substitutions or prerequisite
-    // substitutions/non-patterns, respectively.
-    //
     const location     recipe_loc;     // Buildfile location of the recipe.
     const target_state recipe_state;   // State of recipe library target.
     const adhoc_rule_pattern* pattern; // Ad hoc pattern rule of recipe.
@@ -57,6 +52,21 @@ namespace build2
     //
     virtual bool
     match (action, target&) const override;
+
+    using simple_rule::match; // Unhide the match_extra version.
+
+    // Either this version or the one with match_extra must be overridden.
+    //
+    // If the pattern member above is not NULL then this recipe belongs to an
+    // ad hoc pattern rule and the implementation may need to call the
+    // pattern's apply_*() functions if the pattern has any ad hoc group
+    // member substitutions or prerequisite substitutions/non-patterns,
+    // respectively.
+    //
+    virtual recipe
+    apply (action, target&) const override;
+
+    using simple_rule::apply; // Unhide the match_extra version.
   };
 
   // Note: not exported.