1 files changed, 85 insertions, 0 deletions
diff --git a/src/crimson/osd/object_context.cc b/src/crimson/osd/object_context.cc
new file mode 100644
index 000000000..1ea701c22
--- /dev/null
+++ b/src/crimson/osd/object_context.cc
@@ -0,0 +1,85 @@
+// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
+// vim: ts=8 sw=2 smarttab
+
+#include "crimson/osd/object_context.h"
+
+#include <fmt/ranges.h>
+
+#include "common/Formatter.h"
+#include "crimson/common/config_proxy.h"
+
+namespace {
+  seastar::logger& logger() {
+    return crimson::get_logger(ceph_subsys_osd);
+  }
+}
+
+namespace crimson::osd {
+
+ObjectContextRegistry::ObjectContextRegistry(crimson::common::ConfigProxy &conf)
+{
+  obc_lru.set_target_size(conf.get_val<uint64_t>("crimson_osd_obc_lru_size"));
+  conf.add_observer(this);
+}
+
+ObjectContextRegistry::~ObjectContextRegistry()
+{
+  // purge the cache to avoid leaks and complains from LSan
+  obc_lru.set_target_size(0UL);
+}
+
+const char** ObjectContextRegistry::get_tracked_conf_keys() const
+{
+  static const char* KEYS[] = {
+    "crimson_osd_obc_lru_size",
+    nullptr
+  };
+  return KEYS;
+}
+
+void ObjectContextRegistry::handle_conf_change(
+  const crimson::common::ConfigProxy& conf,
+  const std::set <std::string> &changed)
+{
+  obc_lru.set_target_size(conf.get_val<uint64_t>("crimson_osd_obc_lru_size"));
+}
+
+std::optional<hobject_t> resolve_oid(
+  const SnapSet &ss,
+  const hobject_t &oid)
+{
+  logger().debug("{} oid.snap={},head snapset.seq={}",
+                 __func__, oid.snap, ss.seq);
+  if (oid.snap > ss.seq) {
+    // Because oid.snap > ss.seq, we are trying to read from a snapshot
+    // taken after the most recent write to this object. Read from head.
+    return oid.get_head();
+  } else {
+    // which clone would it be?
+    auto clone = std::lower_bound(
+      begin(ss.clones), end(ss.clones),
+      oid.snap);
+    if (clone == end(ss.clones)) {
+      // Doesn't exist, > last clone, < ss.seq
+      return std::nullopt;
+    }
+    auto citer = ss.clone_snaps.find(*clone);
+    // TODO: how do we want to handle this kind of logic error?
+    ceph_assert(citer != ss.clone_snaps.end());
+
+    if (std::find(
+      citer->second.begin(),
+      citer->second.end(),
+      oid.snap) == citer->second.end()) {
+       logger().debug("{} {} does not contain {} -- DNE",
+                      __func__, ss.clone_snaps, oid.snap);
+       return std::nullopt;
+    } else {
+      auto soid = oid;
+      soid.snap = *clone;
+      return std::optional<hobject_t>(soid);
+    }
+  }
+}
+
+}