Method MakeRoomForWrite

src/leveldb/persistent_cache/persistent_cache_impl.cc:280–307

}

Status PersistentCacheImpl::MakeRoomForWrite(int64_t size) {
  std::lock_guard<std::mutex> _(lock_);
  assert(size_.Get() <= opt_.cache_size);

  if (size + size_.Get() <= opt_.cache_size) {
    // there is enough space to write
    size_.Add(size);
    return Status::OK();
  }

  // there is not enough space to fit the requested data
  // we can clear some space by evicting cold data
  while (size + size_.Get() > opt_.cache_size) {
    std::unique_ptr<CacheFile> f(metadata_.Evict());
    if (!f) {
      // nothing is evictable
      return Status::IOError("No space for writing persistent cache.");
    }
    assert(!f->refs_);
    if (DeleteFileAndReleaseCache(f.get()).ok()) {
      LEVELDB_LOG("Remove evicted cache file: %lu.rc.", f->cacheid());
    }
  }

  size_.Add(size);
  assert(size_.Get() <= opt_.cache_size);
  return Status::OK();
}

bool PersistentCacheImpl::Insert(const Slice& key, CacheFile* file) {
  std::lock_guard<std::mutex> _(lock_);