From a2ccb6406bb1b016aaf31a47c659d06bce0cfc6a Mon Sep 17 00:00:00 2001
From: Boris Kolpackov <boris@codesynthesis.com>
Date: Fri, 25 Sep 2015 10:34:15 +0200
Subject: Add role member to the repository_manifest class

---
 bpkg/manifest               | 20 ++++++++++++++++++
 bpkg/manifest.cxx           | 49 +++++++++++++++++++++++++++++++++++++++++++++
 tests/manifest/repositories |  2 ++
 3 files changed, 71 insertions(+)

diff --git a/bpkg/manifest b/bpkg/manifest
index dfbe5af..75f87bd 100644
--- a/bpkg/manifest
+++ b/bpkg/manifest
@@ -438,10 +438,18 @@ namespace bpkg
     return os << l.string ();
   }
 
+  enum class repository_role
+  {
+    base,
+    prerequisite,
+    complement
+  };
+
   class repository_manifest
   {
   public:
     repository_location location;
+    butl::optional<repository_role> role;
 
   public:
     repository_manifest (manifest_parser&);
@@ -449,6 +457,18 @@ namespace bpkg
 
     void
     serialize (manifest_serializer&) const;
+
+    // Return the effective role of the repository. If the role is not
+    // explicitly specified (see the role member above), then calculate
+    // the role based on the location. Specifically, if the location is
+    // empty, then the effective role is base. Otherwise -- prerequisite.
+    // If the role is specified, then verify that it is consistent with
+    // the location value (that is, base if the location is empty and
+    // prerequisite or complete if not) and return that. Otherwise,
+    // throw logic_error.
+    //
+    repository_role
+    effective_role () const;
   };
 
   class repository_manifests: public std::vector<repository_manifest>
diff --git a/bpkg/manifest.cxx b/bpkg/manifest.cxx
index 1ab9c72..bc1531d 100644
--- a/bpkg/manifest.cxx
+++ b/bpkg/manifest.cxx
@@ -36,6 +36,9 @@ namespace bpkg
   // Utility functions
   //
   static const strings priority_names ({"low", "medium", "high", "security"});
+  static const strings repository_role_names (
+    {"base", "prerequisite", "complement"});
+
   static const string spaces (" \t");
 
   inline static bool
@@ -1126,6 +1129,20 @@ namespace bpkg
           bad_value (e.what ());
         }
       }
+      else if (n == "role")
+      {
+        if (role)
+          bad_name ("role redefinition");
+
+        auto b (repository_role_names.cbegin ());
+        auto e (repository_role_names.cend ());
+        auto i (find (b, e, v));
+
+        if (i == e)
+          bad_value ("unrecognized role");
+
+        role = static_cast<repository_role> (i - b);
+      }
       else
         bad_name ("unknown name '" + n + "' in repository manifest");
     }
@@ -1133,6 +1150,10 @@ namespace bpkg
     // Verify all non-optional values were specified.
     //
     // - location can be omitted
+    // - role can be omitted
+    //
+    if (role && location.empty () != (*role == repository_role::base))
+      bad_value ("invalid role");
   }
 
   void repository_manifest::
@@ -1143,9 +1164,34 @@ namespace bpkg
     if (!location.empty ())
       s.next ("location", location.string ());
 
+    if (role)
+    {
+      if (location.empty () != (*role == repository_role::base))
+        throw serialization (s.name (), "invalid role");
+
+      auto r (static_cast<size_t> (*role));
+      assert (r < repository_role_names.size ());
+      s.next ("role", repository_role_names[r]);
+    }
+
     s.next ("", ""); // End of manifest.
   }
 
+  repository_role repository_manifest::
+  effective_role () const
+  {
+    if (role)
+    {
+      if (location.empty () != (*role == repository_role::base))
+        throw logic_error ("invalid role");
+
+      return *role;
+    }
+    else
+      return location.empty () ?
+        repository_role::base : repository_role::prerequisite;
+  }
+
   // repository_manifests
   //
   repository_manifests::
@@ -1175,6 +1221,9 @@ namespace bpkg
     if (empty () || !back ().location.empty ())
       throw serialization (s.name (), "base repository manifest expected");
 
+    // @@ Should we check that there is location in all except the last
+    // entry?
+    //
     for (const repository_manifest& r: *this)
       r.serialize (s);
 
diff --git a/tests/manifest/repositories b/tests/manifest/repositories
index b446dd4..184a15f 100644
--- a/tests/manifest/repositories
+++ b/tests/manifest/repositories
@@ -1,5 +1,7 @@
 : 1
 location: http://pkg.example.org/1/math
+role: prerequisite
 :
 location: ../stable
+role: complement
 :
-- 
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