1 files changed, 189 insertions, 0 deletions
diff --git a/src/crimson/osd/object_context.h b/src/crimson/osd/object_context.h
new file mode 100644
index 000000000..be238851e
--- /dev/null
+++ b/src/crimson/osd/object_context.h
@@ -0,0 +1,189 @@
+// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
+// vim: ts=8 sw=2 smarttab
+
+#pragma once
+
+#include <map>
+#include <optional>
+#include <utility>
+#include <seastar/core/shared_future.hh>
+#include <seastar/core/shared_ptr.hh>
+
+#include "common/intrusive_lru.h"
+#include "osd/object_state.h"
+#include "crimson/common/exception.h"
+#include "crimson/common/tri_mutex.h"
+#include "crimson/osd/osd_operation.h"
+
+namespace ceph {
+  class Formatter;
+}
+
+namespace crimson::common {
+  class ConfigProxy;
+}
+
+namespace crimson::osd {
+
+class Watch;
+
+template <typename OBC>
+struct obc_to_hoid {
+  using type = hobject_t;
+  const type &operator()(const OBC &obc) {
+    return obc.obs.oi.soid;
+  }
+};
+
+class ObjectContext : public ceph::common::intrusive_lru_base<
+  ceph::common::intrusive_lru_config<
+    hobject_t, ObjectContext, obc_to_hoid<ObjectContext>>>
+{
+public:
+  Ref head; // Ref defined as part of ceph::common::intrusive_lru_base
+  ObjectState obs;
+  std::optional<SnapSet> ss;
+  bool loaded : 1;
+  // the watch / notify machinery rather stays away from the hot and
+  // frequented paths. std::map is used mostly because of developer's
+  // convenience.
+  using watch_key_t = std::pair<uint64_t, entity_name_t>;
+  std::map<watch_key_t, seastar::shared_ptr<crimson::osd::Watch>> watchers;
+
+  ObjectContext(const hobject_t &hoid) : obs(hoid), loaded(false) {}
+
+  const hobject_t &get_oid() const {
+    return obs.oi.soid;
+  }
+
+  bool is_head() const {
+    return get_oid().is_head();
+  }
+
+  const SnapSet &get_ro_ss() const {
+    if (is_head()) {
+      ceph_assert(ss);
+      return *ss;
+    } else {
+      ceph_assert(head);
+      return head->get_ro_ss();
+    }
+  }
+
+  void set_head_state(ObjectState &&_obs, SnapSet &&_ss) {
+    ceph_assert(is_head());
+    obs = std::move(_obs);
+    ss = std::move(_ss);
+    loaded = true;
+  }
+
+  void set_clone_state(ObjectState &&_obs, Ref &&_head) {
+    ceph_assert(!is_head());
+    obs = std::move(_obs);
+    head = _head;
+    loaded = true;
+  }
+
+  /// pass the provided exception to any waiting consumers of this ObjectContext
+  template<typename Exception>
+  void interrupt(Exception ex) {
+    lock.abort(std::move(ex));
+    if (recovery_read_marker) {
+      drop_recovery_read();
+    }
+  }
+
+private:
+  tri_mutex lock;
+  bool recovery_read_marker = false;
+
+  template <typename Lock, typename Func>
+  auto _with_lock(Lock&& lock, Func&& func) {
+    Ref obc = this;
+    return lock.lock().then([&lock, func = std::forward<Func>(func), obc]() mutable {
+      return seastar::futurize_invoke(func).finally([&lock, obc] {
+	lock.unlock();
+      });
+    });
+  }
+
+public:
+  template<RWState::State Type, typename Func>
+  auto with_lock(Func&& func) {
+    switch (Type) {
+    case RWState::RWWRITE:
+      return _with_lock(lock.for_write(), std::forward<Func>(func));
+    case RWState::RWREAD:
+      return _with_lock(lock.for_read(), std::forward<Func>(func));
+    case RWState::RWEXCL:
+      return _with_lock(lock.for_excl(), std::forward<Func>(func));
+    case RWState::RWNONE:
+      return seastar::futurize_invoke(std::forward<Func>(func));
+    default:
+      assert(0 == "noop");
+    }
+  }
+  template<RWState::State Type, typename Func>
+  auto with_promoted_lock(Func&& func) {
+    switch (Type) {
+    case RWState::RWWRITE:
+      return _with_lock(lock.excl_from_write(), std::forward<Func>(func));
+    case RWState::RWREAD:
+      return _with_lock(lock.excl_from_read(), std::forward<Func>(func));
+    case RWState::RWEXCL:
+      return _with_lock(lock.excl_from_excl(), std::forward<Func>(func));
+    case RWState::RWNONE:
+      return _with_lock(lock.for_excl(), std::forward<Func>(func));
+     default:
+      assert(0 == "noop");
+    }
+  }
+
+  bool empty() const {
+    return !lock.is_acquired();
+  }
+  bool is_request_pending() const {
+    return lock.is_acquired();
+  }
+
+  bool get_recovery_read() {
+    if (lock.try_lock_for_read()) {
+      recovery_read_marker = true;
+      return true;
+    } else {
+      return false;
+    }
+  }
+  void wait_recovery_read() {
+    assert(lock.get_readers() > 0);
+    recovery_read_marker = true;
+  }
+  void drop_recovery_read() {
+    assert(recovery_read_marker);
+    recovery_read_marker = false;
+  }
+  bool maybe_get_excl() {
+    return lock.try_lock_for_excl();
+  }
+};
+using ObjectContextRef = ObjectContext::Ref;
+
+class ObjectContextRegistry : public md_config_obs_t  {
+  ObjectContext::lru_t obc_lru;
+
+public:
+  ObjectContextRegistry(crimson::common::ConfigProxy &conf);
+
+  std::pair<ObjectContextRef, bool> get_cached_obc(const hobject_t &hoid) {
+    return obc_lru.get_or_create(hoid);
+  }
+  ObjectContextRef maybe_get_cached_obc(const hobject_t &hoid) {
+    return obc_lru.get(hoid);
+  }
+
+  const char** get_tracked_conf_keys() const final;
+  void handle_conf_change(const crimson::common::ConfigProxy& conf,
+                          const std::set <std::string> &changed) final;
+};
+
+} // namespace crimson::osd