rgw: implement rgw::auth::DecoratedApplier.

Signed-off-by: Radoslaw Zarzynski <rzarzynski@mirantis.com>

diff --git a/src/rgw/rgw_auth_filters.h b/src/rgw/rgw_auth_filters.h
new file mode 100644 (file)
index 0000000..da59ab1
--- /dev/null
+++ b/src/rgw/rgw_auth_filters.h
@@ -0,0 +1,99 @@
+// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
+// vim: ts=8 sw=2 smarttab
+
+#ifndef CEPH_RGW_AUTH_FILTERS_H
+#define CEPH_RGW_AUTH_FILTERS_H
+
+#include <type_traits>
+
+#include <boost/optional.hpp>
+
+#include "rgw_common.h"
+#include "rgw_auth.h"
+
+namespace rgw {
+namespace auth {
+
+/* Abstract decorator over any implementation of rgw::auth::IdentityApplier
+ * which could be provided both as a pointer-to-object or the object itself. */
+template <typename DecorateeT>
+class DecoratedApplier : public rgw::auth::IdentityApplier {
+  typedef typename std::remove_pointer<DecorateeT>::type DerefedDecorateeT;
+
+  static_assert(std::is_base_of<rgw::auth::IdentityApplier,
+                                DerefedDecorateeT>::value,
+                "DecorateeT must be a subclass of rgw::auth::IdentityApplier");
+
+  DecorateeT decoratee;
+
+  /* There is an indirection layer over accessing decoratee to share the same
+   * code base between dynamic and static decorators. The difference is about
+   * what we store internally: pointer to a decorated object versus the whole
+   * object itself. Googling for "SFINAE" can help to understand the code. */
+  template <typename T = void,
+            typename std::enable_if<
+    std::is_pointer<DecorateeT>::value, T>::type* = nullptr>
+  DerefedDecorateeT& get_decoratee() {
+    return *decoratee;
+  }
+
+  template <typename T = void,
+            typename std::enable_if<
+    ! std::is_pointer<DecorateeT>::value, T>::type* = nullptr>
+  DerefedDecorateeT& get_decoratee() {
+    return decoratee;
+  }
+
+  template <typename T = void,
+            typename std::enable_if<
+    std::is_pointer<DecorateeT>::value, T>::type* = nullptr>
+  const DerefedDecorateeT& get_decoratee() const {
+    return *decoratee;
+  }
+
+  template <typename T = void,
+            typename std::enable_if<
+    ! std::is_pointer<DecorateeT>::value, T>::type* = nullptr>
+  const DerefedDecorateeT& get_decoratee() const {
+    return decoratee;
+  }
+
+public:
+  DecoratedApplier(DecorateeT&& decoratee)
+    : decoratee(std::forward<DecorateeT>(decoratee)) {
+  }
+
+  uint32_t get_perms_from_aclspec(const aclspec_t& aclspec) const override {
+    return get_decoratee().get_perms_from_aclspec(aclspec);
+  }
+
+  bool is_admin_of(const rgw_user& uid) const override {
+    return get_decoratee().is_admin_of(uid);
+  }
+
+  bool is_owner_of(const rgw_user& uid) const override {
+    return get_decoratee().is_owner_of(uid);
+  }
+
+  uint32_t get_perm_mask() const override {
+    return get_decoratee().get_perm_mask();
+  }
+
+  void to_str(std::ostream& out) const override {
+    get_decoratee().to_str(out);
+  }
+
+  void load_acct_info(RGWUserInfo& user_info) const override {  /* out */
+    return get_decoratee().load_acct_info(user_info);
+  }
+
+  void modify_request_state(req_state * s) const override {     /* in/out */
+    return get_decoratee().modify_request_state(s);
+  }
+};
+
+
+} /* namespace auth */
+} /* namespace rgw */
+
+#endif /* CEPH_RGW_AUTH_FILTERS_H */