From 9034f7c51ef6437ce9d4547ba5bde217b4740fb2 Mon Sep 17 00:00:00 2001
From: Boris Kolpackov <boris@codesynthesis.com>
Date: Tue, 19 Apr 2022 11:10:53 +0200
Subject: Use target recipe for auxiliary data storage during match-apply

In particular, we now have separate auxiliary data storage for inner
and outer operations.
---
 libbuild2/version/rule.cxx | 39 ++++++++++++++++++++++++++++++++-------
 libbuild2/version/rule.hxx |  3 +++
 2 files changed, 35 insertions(+), 7 deletions(-)

(limited to 'libbuild2/version')

diff --git a/libbuild2/version/rule.cxx b/libbuild2/version/rule.cxx
index ad26da4..1799666 100644
--- a/libbuild2/version/rule.cxx
+++ b/libbuild2/version/rule.cxx
@@ -46,6 +46,25 @@ namespace build2
 
     // in_rule
     //
+
+    // Wrap the in::rule's perform_update recipe into a data-carrying recipe.
+    //
+    // To optimize this a bit further (i.e., to avoid the dynamic memory
+    // allocation) we are going to call in::rule::perform_update() directly
+    // (after all it's virtual and thus part of the in_rule's interface).
+    //
+    struct match_data
+    {
+      const module& mod;
+      const in_rule& rule;
+
+      target_state
+      operator() (action a, const target& t)
+      {
+        return rule.perform_update (a, t);
+      }
+    };
+
     bool in_rule::
     match (action a, target& xt) const
     {
@@ -74,14 +93,20 @@ namespace build2
       if (!fi)
         l5 ([&]{trace << "no in file prerequisite for target " << t;});
 
-      bool r (fm && fi);
+      return fm && fi;
+    }
+
+    recipe in_rule::
+    apply (action a, target& t) const
+    {
+      recipe r (rule::apply (a, t));
 
-      // If we match, lookup and cache the module for the update operation.
+      // Lookup and cache the module for the update operation.
       //
-      if (r && a == perform_update_id)
-        t.data (rs.find_module<module> (module::name));
-
-      return r;
+      return a == perform_update_id
+        ? match_data {*t.root_scope ().find_module<module> (module::name),
+                      *this}
+        : move (r);
     }
 
     string in_rule::
@@ -97,7 +122,7 @@ namespace build2
       // Note that this code will be executed during up-to-date check for each
       // substitution so let's try not to do anything overly sub-optimal here.
       //
-      const module& m (*t.data<const module*> ());
+      const module& m (t.data<match_data> (a).mod);
 
       // Split it into the package name and the variable/condition name.
       //
diff --git a/libbuild2/version/rule.hxx b/libbuild2/version/rule.hxx
index 55b4aee..ba673e5 100644
--- a/libbuild2/version/rule.hxx
+++ b/libbuild2/version/rule.hxx
@@ -25,6 +25,9 @@ namespace build2
       virtual bool
       match (action, target&) const override;
 
+      virtual recipe
+      apply (action, target&) const override;
+
       virtual string
       lookup (const location&,
               action,
-- 
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