From e05f7c7383cc48823bd408c0bc5187191a9a1c48 Mon Sep 17 00:00:00 2001
From: Boris Kolpackov <boris@codesynthesis.com>
Date: Tue, 23 May 2023 09:23:16 +0200
Subject: Explicit group: static members

---
 libbuild2/target.cxx | 38 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 38 insertions(+)

(limited to 'libbuild2/target.cxx')

diff --git a/libbuild2/target.cxx b/libbuild2/target.cxx
index a9ae47a..c1002b9 100644
--- a/libbuild2/target.cxx
+++ b/libbuild2/target.cxx
@@ -1217,6 +1217,42 @@ namespace build2
     target_type::flag::none
   };
 
+  // group
+  //
+  group_view group::
+  group_members (action a) const
+  {
+    if (members_on == 0) // Not yet discovered.
+      return group_view {nullptr, 0};
+
+    // Members discovered during anything other than perform_update are only
+    // good for that operation. For example, we only return the static members
+    // ("representative sample") for perform_configure.
+    //
+    // We also re-discover the members on each update and clean not to
+    // overcomplicate the already twisted adhoc_buildscript_rule::apply()
+    // logic.
+    //
+    if (members_on != ctx.current_on)
+    {
+      if (members_action != perform_update_id ||
+          a == perform_update_id ||
+          a == perform_clean_id)
+        return group_view {nullptr, 0};
+    }
+
+    // Note that we may have no members (e.g., perform_configure and there are
+    // no static members). However, whether std::vector returns a non-NULL
+    // pointer in this case is undefined.
+    //
+    size_t n (members.size ());
+    return group_view {
+      n != 0
+      ? members.data ()
+      : reinterpret_cast<const target* const*> (this),
+      n};
+  }
+
   const target_type group::static_type
   {
     "group",
@@ -1230,6 +1266,8 @@ namespace build2
     target_type::flag::group
   };
 
+  // alias
+  //
   static const target*
   alias_search (const target& t, const prerequisite_key& pk)
   {
-- 
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