Add $bin.link_member() function

Given a linker output target type ("exe", "lib[as]", or "libu[eas]") return
the target type of lib{} group member ("liba" or "libs") that will be picked
when linking a lib{} group to this target type.

1 files changed, 31 insertions, 4 deletions

diff --git a/libbuild2/bin/utility.ixx b/libbuild2/bin/utility.ixx
index 91c919b..65dffa8 100644
--- a/libbuild2/bin/utility.ixx
+++ b/libbuild2/bin/utility.ixx
@@ -6,16 +6,43 @@ namespace build2
   namespace bin
   {
     inline ltype
-    link_type (const target& t)
+    link_type (const target_type& tt)
     {
       bool u (false);
       otype o (
-        t.is_a<exe>  () || (u = t.is_a<libue> ()) ? otype::e :
-        t.is_a<liba> () || (u = t.is_a<libua> ()) ? otype::a :
-        t.is_a<libs> () || (u = t.is_a<libus> ()) ? otype::s :
+        tt.is_a<exe>  () || (u = tt.is_a<libue> ()) ? otype::e :
+        tt.is_a<liba> () || (u = tt.is_a<libua> ()) ? otype::a :
+        tt.is_a<libs> () || (u = tt.is_a<libus> ()) ? otype::s :
         static_cast<otype> (0xFF));
 
       return ltype {o, u};
     }
+
+    inline pair<otype, bool>
+    link_member (lmembers lm, lorder lo)
+    {
+      bool r (true);
+
+      bool s (true);
+      switch (lo)
+      {
+      case lorder::a:
+      case lorder::a_s:
+        s = false; // Fall through.
+      case lorder::s:
+      case lorder::s_a:
+        {
+          if (s ? !lm.s : !lm.a)
+          {
+            if (lo == lorder::a_s || lo == lorder::s_a)
+              s = !s;
+            else
+              r = false; // Not available.
+          }
+        }
+      }
+
+      return make_pair (s ? otype::s : otype::a, r);
+    }
   }
 }