1 files changed, 137 insertions, 0 deletions
diff --git a/src/rocksdb/table/get_context.h b/src/rocksdb/table/get_context.h
new file mode 100644
index 00000000..d7d0e980
--- /dev/null
+++ b/src/rocksdb/table/get_context.h
@@ -0,0 +1,137 @@
+//  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).
+
+#pragma once
+#include <string>
+#include "db/merge_context.h"
+#include "db/read_callback.h"
+#include "rocksdb/env.h"
+#include "rocksdb/statistics.h"
+#include "rocksdb/types.h"
+#include "table/block.h"
+
+namespace rocksdb {
+class MergeContext;
+class PinnedIteratorsManager;
+
+struct GetContextStats {
+  uint64_t num_cache_hit = 0;
+  uint64_t num_cache_index_hit = 0;
+  uint64_t num_cache_data_hit = 0;
+  uint64_t num_cache_filter_hit = 0;
+  uint64_t num_cache_compression_dict_hit = 0;
+  uint64_t num_cache_index_miss = 0;
+  uint64_t num_cache_filter_miss = 0;
+  uint64_t num_cache_data_miss = 0;
+  uint64_t num_cache_compression_dict_miss = 0;
+  uint64_t num_cache_bytes_read = 0;
+  uint64_t num_cache_miss = 0;
+  uint64_t num_cache_add = 0;
+  uint64_t num_cache_bytes_write = 0;
+  uint64_t num_cache_index_add = 0;
+  uint64_t num_cache_index_bytes_insert = 0;
+  uint64_t num_cache_data_add = 0;
+  uint64_t num_cache_data_bytes_insert = 0;
+  uint64_t num_cache_filter_add = 0;
+  uint64_t num_cache_filter_bytes_insert = 0;
+  uint64_t num_cache_compression_dict_add = 0;
+  uint64_t num_cache_compression_dict_bytes_insert = 0;
+};
+
+class GetContext {
+ public:
+  enum GetState {
+    kNotFound,
+    kFound,
+    kDeleted,
+    kCorrupt,
+    kMerge,  // saver contains the current merge result (the operands)
+    kBlobIndex,
+  };
+  GetContextStats get_context_stats_;
+
+  GetContext(const Comparator* ucmp, const MergeOperator* merge_operator,
+             Logger* logger, Statistics* statistics, GetState init_state,
+             const Slice& user_key, PinnableSlice* value, bool* value_found,
+             MergeContext* merge_context,
+             SequenceNumber* max_covering_tombstone_seq, Env* env,
+             SequenceNumber* seq = nullptr,
+             PinnedIteratorsManager* _pinned_iters_mgr = nullptr,
+             ReadCallback* callback = nullptr, bool* is_blob_index = nullptr);
+
+  void MarkKeyMayExist();
+
+  // Records this key, value, and any meta-data (such as sequence number and
+  // state) into this GetContext.
+  //
+  // If the parsed_key matches the user key that we are looking for, sets
+  // mathced to true.
+  //
+  // Returns True if more keys need to be read (due to merges) or
+  //         False if the complete value has been found.
+  bool SaveValue(const ParsedInternalKey& parsed_key, const Slice& value,
+                 bool* matched, Cleanable* value_pinner = nullptr);
+
+  // Simplified version of the previous function. Should only be used when we
+  // know that the operation is a Put.
+  void SaveValue(const Slice& value, SequenceNumber seq);
+
+  GetState State() const { return state_; }
+
+  SequenceNumber* max_covering_tombstone_seq() {
+    return max_covering_tombstone_seq_;
+  }
+
+  PinnedIteratorsManager* pinned_iters_mgr() { return pinned_iters_mgr_; }
+
+  // If a non-null string is passed, all the SaveValue calls will be
+  // logged into the string. The operations can then be replayed on
+  // another GetContext with replayGetContextLog.
+  void SetReplayLog(std::string* replay_log) { replay_log_ = replay_log; }
+
+  // Do we need to fetch the SequenceNumber for this key?
+  bool NeedToReadSequence() const { return (seq_ != nullptr); }
+
+  bool sample() const { return sample_; }
+
+  bool CheckCallback(SequenceNumber seq) {
+    if (callback_) {
+      return callback_->IsVisible(seq);
+    }
+    return true;
+  }
+
+  void ReportCounters();
+
+ private:
+  const Comparator* ucmp_;
+  const MergeOperator* merge_operator_;
+  // the merge operations encountered;
+  Logger* logger_;
+  Statistics* statistics_;
+
+  GetState state_;
+  Slice user_key_;
+  PinnableSlice* pinnable_val_;
+  bool* value_found_;  // Is value set correctly? Used by KeyMayExist
+  MergeContext* merge_context_;
+  SequenceNumber* max_covering_tombstone_seq_;
+  Env* env_;
+  // If a key is found, seq_ will be set to the SequenceNumber of most recent
+  // write to the key or kMaxSequenceNumber if unknown
+  SequenceNumber* seq_;
+  std::string* replay_log_;
+  // Used to temporarily pin blocks when state_ == GetContext::kMerge
+  PinnedIteratorsManager* pinned_iters_mgr_;
+  ReadCallback* callback_;
+  bool sample_;
+  bool* is_blob_index_;
+};
+
+void replayGetContextLog(const Slice& replay_log, const Slice& user_key,
+                         GetContext* get_context,
+                         Cleanable* value_pinner = nullptr);
+
+}  // namespace rocksdb