rgw/metadata: add RGWMetadataLister abstraction

Signed-off-by: Casey Bodley <cbodley@redhat.com>

diff --git a/src/rgw/driver/rados/rgw_metadata_lister.h b/src/rgw/driver/rados/rgw_metadata_lister.h
new file mode 100644 (file)
index 0000000..9fbb21a
--- /dev/null
+++ b/src/rgw/driver/rados/rgw_metadata_lister.h
@@ -0,0 +1,73 @@
+// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
+// vim: ts=8 sw=2 smarttab ft=cpp
+
+/*
+ * Ceph - scalable distributed file system
+ *
+ * Copyright contributors to the Ceph project
+ *
+ * This is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License version 2.1, as published by the Free Software
+ * Foundation. See file COPYING.
+ *
+ */
+
+#pragma once
+
+#include <algorithm>
+#include <iterator>
+#include <list>
+#include <string>
+#include <vector>
+#include "services/svc_sys_obj.h"
+
+class DoutPrefixProvider;
+
+class RGWMetadataLister {
+  RGWSI_SysObj::Pool pool;
+  RGWSI_SysObj::Pool::Op listing;
+
+  virtual void filter_transform(std::vector<std::string>& oids,
+                                std::list<std::string>& keys) {
+    // use all oids as keys
+    std::move(oids.begin(), oids.end(), std::back_inserter(keys));
+  }
+
+ public:
+  explicit RGWMetadataLister(RGWSI_SysObj::Pool pool)
+    : pool(pool), listing(this->pool) {}
+  virtual ~RGWMetadataLister() {}
+
+  int init(const DoutPrefixProvider* dpp,
+           const std::string& marker,
+           const std::string& prefix)
+  {
+    return listing.init(dpp, marker, prefix);
+  }
+
+  int get_next(const DoutPrefixProvider* dpp, int max,
+               std::list<std::string>& keys, bool* truncated)
+  {
+    std::vector<std::string> oids;
+    int r = listing.get_next(dpp, max, &oids, truncated);
+    if (r == -ENOENT) {
+      if (truncated) {
+        *truncated = false;
+      }
+      return 0;
+    }
+    if (r < 0) {
+      return r;
+    }
+    filter_transform(oids, keys);
+    return 0;
+  }
+
+  std::string get_marker()
+  {
+    std::string marker;
+    listing.get_marker(&marker);
+    return marker;
+  }
+};