From aba1015640643a11bbd98d8483805ca5dd8cbd96 Mon Sep 17 00:00:00 2001
From: Boris Kolpackov <boris@codesynthesis.com>
Date: Tue, 19 May 2020 14:41:49 +0200
Subject: Add recipe library target state to cxx_rule

---
 libbuild2/rule.cxx | 10 +++++-----
 libbuild2/rule.hxx | 13 ++++++++++---
 2 files changed, 15 insertions(+), 8 deletions(-)

diff --git a/libbuild2/rule.cxx b/libbuild2/rule.cxx
index d5d6661..9df5f67 100644
--- a/libbuild2/rule.cxx
+++ b/libbuild2/rule.cxx
@@ -667,7 +667,7 @@ namespace build2
       if ((impl = this->impl.load (memory_order_relaxed)) != nullptr)
         break;
 
-      using create_function = cxx_rule* (const location&);
+      using create_function = cxx_rule* (const location&, target_state);
       using load_function = create_function* ();
 
       // The only way to guarantee that the name of our module matches its
@@ -888,9 +888,9 @@ namespace build2
         // user-defined.
         //
         ofs << "  static cxx_rule*"                                     << '\n'
-            << "  create_" << id << " (const location& l)"              << '\n'
+            << "  create_" << id << " (const location& l, target_state s)" << '\n'
             << "  {"                                                    << '\n'
-            << "    return new rule (l);"                               << '\n'
+            << "    return new rule (l, s);"                            << '\n'
             << "  }"                                                    << '\n'
             << '\n';
 
@@ -920,7 +920,7 @@ namespace build2
             << "#ifdef _WIN32"                                          << '\n'
             << "__declspec(dllexport)"                                  << '\n'
             << "#endif"                                                 << '\n'
-            << "cxx_rule* (*" << sym << " ()) (const location&)"        << '\n'
+            << "cxx_rule* (*" << sym << " ()) (const location&, target_state)" << '\n'
             << "{"                                                      << '\n'
             << "  return &rule_" << id << "::create_" << id << ";"      << '\n'
             << "}"                                                      << '\n'
@@ -1098,7 +1098,7 @@ namespace build2
         load_function* lf (function_cast<load_function*> (hs.second));
         create_function* cf (lf ());
 
-        impl = cf (loc);
+        impl = cf (loc, l->executed_state (perform_update_id));
         this->impl.store (impl, memory_order_relaxed); // Still in load phase.
       }
     }
diff --git a/libbuild2/rule.hxx b/libbuild2/rule.hxx
index a3d54e7..50ed126 100644
--- a/libbuild2/rule.hxx
+++ b/libbuild2/rule.hxx
@@ -199,10 +199,17 @@ namespace build2
   class LIBBUILD2_SYMEXPORT cxx_rule: public rule
   {
   public:
-    const location loc; // Buildfile location of the recipe.
 
-    explicit
-    cxx_rule (const location& l): loc (l) {}
+    // A robust recipe may want to incorporate the recipe_state into its
+    // up-to-date decision as if the recipe library was a prerequisite (it
+    // cannot be injected as a real prerequisite since it's from a different
+    // build context).
+    //
+    const location     recipe_loc;   // Buildfile location of the recipe.
+    const target_state recipe_state; // State of recipe library target.
+
+    cxx_rule (const location& l, target_state s)
+      : recipe_loc (l), recipe_state (s) {}
 
     // Return true by default.
     //
-- 
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