Squashed 'src/rocksdb/' content from commit 224932d

git-subtree-dir: src/rocksdb
git-subtree-split: 224932d4d0

db/table_cache.h

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+//  Copyright (c) 2013, Facebook, Inc.  All rights reserved.
+//  This source code is licensed under the BSD-style license found in the
+//  LICENSE file in the root directory of this source tree. An additional grant
+//  of patent rights can be found in the PATENTS file in the same directory.
+//
+// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file. See the AUTHORS file for names of contributors.
+//
+// Thread-safe (provides internal synchronization)
+
+#pragma once
+#include <string>
+#include <vector>
+#include <stdint.h>
+
+#include "db/dbformat.h"
+#include "port/port.h"
+#include "rocksdb/cache.h"
+#include "rocksdb/env.h"
+#include "rocksdb/table.h"
+#include "table/table_reader.h"
+
+namespace rocksdb {
+
+class Env;
+class Arena;
+struct FileDescriptor;
+
+class TableCache {
+ public:
+  TableCache(const Options* options, const EnvOptions& storage_options,
+             Cache* cache);
+  ~TableCache();
+
+  // Return an iterator for the specified file number (the corresponding
+  // file length must be exactly "file_size" bytes).  If "tableptr" is
+  // non-nullptr, also sets "*tableptr" to point to the Table object
+  // underlying the returned iterator, or nullptr if no Table object underlies
+  // the returned iterator.  The returned "*tableptr" object is owned by
+  // the cache and should not be deleted, and is valid for as long as the
+  // returned iterator is live.
+  Iterator* NewIterator(const ReadOptions& options, const EnvOptions& toptions,
+                        const InternalKeyComparator& internal_comparator,
+                        const FileDescriptor& file_fd,
+                        TableReader** table_reader_ptr = nullptr,
+                        bool for_compaction = false, Arena* arena = nullptr);
+
+  // If a seek to internal key "k" in specified file finds an entry,
+  // call (*handle_result)(arg, found_key, found_value) repeatedly until
+  // it returns false.
+  Status Get(const ReadOptions& options,
+             const InternalKeyComparator& internal_comparator,
+             const FileDescriptor& file_fd, const Slice& k, void* arg,
+             bool (*handle_result)(void*, const ParsedInternalKey&,
+                                   const Slice&),
+             void (*mark_key_may_exist)(void*) = nullptr);
+
+  // Evict any entry for the specified file number
+  static void Evict(Cache* cache, uint64_t file_number);
+
+  // Find table reader
+  Status FindTable(const EnvOptions& toptions,
+                   const InternalKeyComparator& internal_comparator,
+                   const FileDescriptor& file_fd, Cache::Handle**,
+                   const bool no_io = false);
+
+  // Get TableReader from a cache handle.
+  TableReader* GetTableReaderFromHandle(Cache::Handle* handle);
+
+  // Get the table properties of a given table.
+  // @no_io: indicates if we should load table to the cache if it is not present
+  //         in table cache yet.
+  // @returns: `properties` will be reset on success. Please note that we will
+  //            return Status::Incomplete() if table is not present in cache and
+  //            we set `no_io` to be true.
+  Status GetTableProperties(const EnvOptions& toptions,
+                            const InternalKeyComparator& internal_comparator,
+                            const FileDescriptor& file_meta,
+                            std::shared_ptr<const TableProperties>* properties,
+                            bool no_io = false);
+
+  // Return total memory usage of the table reader of the file.
+  // 0 of table reader of the file is not loaded.
+  size_t GetMemoryUsageByTableReader(
+      const EnvOptions& toptions,
+      const InternalKeyComparator& internal_comparator,
+      const FileDescriptor& fd);
+
+  // Release the handle from a cache
+  void ReleaseHandle(Cache::Handle* handle);
+
+ private:
+  Env* const env_;
+  const std::vector<DbPath> db_paths_;
+  const Options* options_;
+  const EnvOptions& storage_options_;
+  Cache* const cache_;
+};
+
+}  // namespace rocksdb