2 files changed, 52 insertions, 1 deletions

diff --git a/include/Makefile.am b/include/Makefile.am
index 4b9b02a..2c190b8 100644
--- a/include/Makefile.am
+++ b/include/Makefile.am
@@ -4,10 +4,11 @@ nobase_include_HEADERS = \
         opkele/types.h \
         opkele/association.h \
         opkele/exception.h \
         opkele/server.h \
         opkele/consumer.h \
         opkele/extension.h \
-        opkele/sreg.h
+        opkele/sreg.h \
+        opkele/extension_chain.h
 EXTRA_DIST = \
         opkele/data.h \
         opkele/util.h
diff --git a/include/opkele/extension_chain.h b/include/opkele/extension_chain.h
new file mode 100644
index 0000000..955f4d5
--- a/dev/null
+++ b/include/opkele/extension_chain.h
@@ -0,0 +1,50 @@
+#ifndef __OPKELE_EXTENSION_CHAIN_H
+#define __OPKELE_EXTENSION_CHAIN_H
+
+/**
+ * @file
+ * @brief extension chain extension
+ */
+
+#include <list>
+#include <opkele/extension.h>
+
+/**
+ * @brief the main opkele namespace
+ */
+namespace opkele {
+    using std::list;
+
+    /**
+     * OpenID extensions chain used to combine extensions, it is actually an
+     * stl list of pointers to extensions.
+     */
+    class extension_chain_t : public extension_t, public list<extension_t*> {
+        public:
+
+            /**
+             * Default constructor creates an empty chain
+             */
+            extension_chain_t() { }
+            /**
+             * Create extension chain with a single extension in it
+             */
+            extension_chain_t(extension_t *e) { push_back(e); }
+
+            /**
+             * Implementation of consumer's checkid hook
+             */
+            virtual void checkid_hook(params_t& p,const string& identity);
+            /**
+             * Implementation of consumer's id_res hook
+             */
+            virtual void id_res_hook(const params_t& p,const params_t& sp,const string& identity);
+            /**
+             * Implementation of server's checkid_hook
+             */
+            virtual void checkid_hook(const params_t& pin,params_t& pout);
+    };
+
+}
+
+#endif /* __OPKELE_EXTENSION_CHAIN_H */