[msitools] wixl: introduce WixResolver

[Paolo Bonzini <pbonzini src gnome org>]

commit ac82ebd7518aab2ac905f5e1a2bedb9a43b830f6
Author: Paolo Bonzini <pbonzini redhat com>
Date:   Thu Jan 24 21:16:42 2013 +0100

    wixl: introduce WixResolver

 tools/wixl/builder.vala |   22 +---------------------
 tools/wixl/wix.vala     |   24 ++++++++++++++++++++++++
 2 files changed, 25 insertions(+), 21 deletions(-)
---
diff --git a/tools/wixl/builder.vala b/tools/wixl/builder.vala
index 55f16f6..bb5510b 100644
--- a/tools/wixl/builder.vala
+++ b/tools/wixl/builder.vala
@@ -1,6 +1,6 @@
 namespace Wixl {
 
-    class WixBuilder: WixNodeVisitor {
+    class WixBuilder: WixNodeVisitor, WixResolver {
 
         public WixBuilder (string[] includedirs) {
             add_path (".");
@@ -324,26 +324,6 @@ namespace Wixl {
             SHARED,
         }
 
-        G? resolve<G> (WixElement element) throws GLib.Error {
-            G? resolved = null;
-
-            if (element.get_type () == typeof (G))
-                resolved = element;
-            else if (element is WixElementRef) {
-                var ref = element as WixElementRef<G>;
-                if (ref.ref_type != typeof (G))
-                    resolved = null;
-                else if (ref.resolved == null)
-                    ref.resolved = find_element<G> (element.Id);
-                resolved = ref.resolved;
-            }
-
-            if (resolved == null)
-                throw new Wixl.Error.FAILED ("couldn't resolve %s", element.Id);
-
-            return resolved;
-        }
-
         public override void visit_component (WixComponent comp) throws GLib.Error {
             var attr = 0;
 
diff --git a/tools/wixl/wix.vala b/tools/wixl/wix.vala
index beacd2f..205721b 100644
--- a/tools/wixl/wix.vala
+++ b/tools/wixl/wix.vala
@@ -1,5 +1,29 @@
 namespace Wixl {
 
+    public interface WixResolver {
+        public abstract G? find_element<G> (string Id);
+
+        public G? resolve<G> (WixElement element) throws GLib.Error {
+            G? resolved = null;
+
+            if (element.get_type ().is_a (typeof (G)))
+                resolved = element;
+            else if (element is WixElementRef) {
+                var ref = element as WixElementRef<G>;
+                if (!ref.ref_type.is_a (typeof (G)))
+                    resolved = null;
+                else if (ref.resolved == null)
+                    ref.resolved = find_element<G> (element.Id);
+                resolved = ref.resolved;
+            }
+
+            if (resolved == null)
+                throw new Wixl.Error.FAILED ("couldn't resolve %s", element.Id);
+
+            return resolved;
+        }
+    }
+
     public enum VisitState {
         ENTER,
         INFIX,