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rocksdb/cache/secondary_cache.cc

44 lines
1.5 KiB

// Copyright (c) 2011-present, Facebook, Inc. All rights reserved.
// This source code is licensed under both the GPLv2 (found in the
// COPYING file in the root directory) and Apache 2.0 License
// (found in the LICENSE.Apache file in the root directory).
#include "rocksdb/secondary_cache.h"
#include "cache/cache_entry_roles.h"
namespace ROCKSDB_NAMESPACE {
namespace {
void NoopDelete(Cache::ObjectPtr, MemoryAllocator*) {}
size_t SliceSize(Cache::ObjectPtr obj) {
return static_cast<Slice*>(obj)->size();
}
Status SliceSaveTo(Cache::ObjectPtr from_obj, size_t from_offset, size_t length,
char* out) {
const Slice& slice = *static_cast<Slice*>(from_obj);
std::memcpy(out, slice.data() + from_offset, length);
return Status::OK();
}
Status FailCreate(const Slice&, Cache::CreateContext*, MemoryAllocator*,
Cache::ObjectPtr*, size_t*) {
return Status::NotSupported("Only for dumping data into SecondaryCache");
}
} // namespace
Status SecondaryCache::InsertSaved(const Slice& key, const Slice& saved) {
static Cache::CacheItemHelper helper_no_secondary{CacheEntryRole::kMisc,
&NoopDelete};
static Cache::CacheItemHelper helper{
CacheEntryRole::kMisc, &NoopDelete, &SliceSize,
&SliceSaveTo, &FailCreate, &helper_no_secondary};
// NOTE: depends on Insert() being synchronous, not keeping pointer `&saved`
return Insert(key, const_cast<Slice*>(&saved), &helper);
}
} // namespace ROCKSDB_NAMESPACE