ceph/src/crimson/os/alienstore/alien_collection.h

   1 // -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
   2 // vim: ts=8 sw=2 smarttab
   3
   4 #pragma once
   5
   6 #include "os/ObjectStore.h"
   7
   8 #include "crimson/os/futurized_collection.h"
   9 #include "crimson/os/futurized_store.h"
  10 #include "alien_store.h"
  11
  12 namespace crimson::os {
  13
  14 class AlienCollection final : public FuturizedCollection {
  15 public:
  16   AlienCollection(ObjectStore::CollectionHandle ch)
  17   : FuturizedCollection(ch->cid),
  18     collection(ch) {}
  19
  20   ~AlienCollection() {}
  21
  22   template <typename Func, typename Result = std::invoke_result_t<Func>>
  23   seastar::futurize_t<Result> with_lock(Func&& func) {
  24     // newer versions of Seastar provide two variants of `with_lock`
  25     //   - generic, friendly towards throwing move constructors of Func,
  26     //   - specialized for `noexcept`.
  27     // unfortunately, the former has a limitation: the return value
  28     // of `Func` must be compatible with `current_exception_as_future()`
  29     // which boils down to returning `seastar::future<void>`.
  30     static_assert(std::is_nothrow_move_constructible_v<Func>);
  31     return seastar::with_lock(mutex, std::forward<Func>(func));
  32   }
  33
  34 private:
  35   ObjectStore::CollectionHandle collection;
  36   seastar::shared_mutex mutex;
  37   friend AlienStore;
  38 };
  39 }