bool GetContext::SaveValue()

in table/get_context.cc [220:367]
120 lines of code
46 McCabe index (conditional complexity)

bool GetContext::SaveValue(const ParsedInternalKey& parsed_key,
                           const Slice& value, bool* matched,
                           Cleanable* value_pinner) {
  assert(matched);
  assert((state_ != kMerge && parsed_key.type != kTypeMerge) ||
         merge_context_ != nullptr);
  if (ucmp_->EqualWithoutTimestamp(parsed_key.user_key, user_key_)) {
    *matched = true;
    // If the value is not in the snapshot, skip it
    if (!CheckCallback(parsed_key.sequence)) {
      return true;  // to continue to the next seq
    }

    appendToReplayLog(replay_log_, parsed_key.type, value);

    if (seq_ != nullptr) {
      // Set the sequence number if it is uninitialized
      if (*seq_ == kMaxSequenceNumber) {
        *seq_ = parsed_key.sequence;
      }
    }

    auto type = parsed_key.type;
    // Key matches. Process it
    if ((type == kTypeValue || type == kTypeMerge || type == kTypeBlobIndex) &&
        max_covering_tombstone_seq_ != nullptr &&
        *max_covering_tombstone_seq_ > parsed_key.sequence) {
      type = kTypeRangeDeletion;
    }
    switch (type) {
      case kTypeValue:
      case kTypeBlobIndex:
        assert(state_ == kNotFound || state_ == kMerge);
        if (type == kTypeBlobIndex && is_blob_index_ == nullptr) {
          // Blob value not supported. Stop.
          state_ = kUnexpectedBlobIndex;
          return false;
        }
        if (is_blob_index_ != nullptr) {
          *is_blob_index_ = (type == kTypeBlobIndex);
        }
        if (kNotFound == state_) {
          state_ = kFound;
          if (do_merge_) {
            if (LIKELY(pinnable_val_ != nullptr)) {
              if (LIKELY(value_pinner != nullptr)) {
                // If the backing resources for the value are provided, pin them
                pinnable_val_->PinSlice(value, value_pinner);
              } else {
                TEST_SYNC_POINT_CALLBACK("GetContext::SaveValue::PinSelf",
                                         this);
                // Otherwise copy the value
                pinnable_val_->PinSelf(value);
              }
            }
          } else {
            // It means this function is called as part of DB GetMergeOperands
            // API and the current value should be part of
            // merge_context_->operand_list
            if (is_blob_index_ != nullptr && *is_blob_index_) {
              PinnableSlice pin_val;
              if (GetBlobValue(value, &pin_val) == false) {
                return false;
              }
              Slice blob_value(pin_val);
              push_operand(blob_value, nullptr);
            } else {
              push_operand(value, value_pinner);
            }
          }
        } else if (kMerge == state_) {
          assert(merge_operator_ != nullptr);
          if (is_blob_index_ != nullptr && *is_blob_index_) {
            PinnableSlice pin_val;
            if (GetBlobValue(value, &pin_val) == false) {
              return false;
            }
            Slice blob_value(pin_val);
            state_ = kFound;
            if (do_merge_) {
              Merge(&blob_value);
            } else {
              // It means this function is called as part of DB GetMergeOperands
              // API and the current value should be part of
              // merge_context_->operand_list
              push_operand(blob_value, nullptr);
            }
          } else {
            state_ = kFound;
            if (do_merge_) {
              Merge(&value);
            } else {
              // It means this function is called as part of DB GetMergeOperands
              // API and the current value should be part of
              // merge_context_->operand_list
              push_operand(value, value_pinner);
            }
          }
        }
        if (state_ == kFound) {
          size_t ts_sz = ucmp_->timestamp_size();
          if (ts_sz > 0 && timestamp_ != nullptr) {
            Slice ts = ExtractTimestampFromUserKey(parsed_key.user_key, ts_sz);
            timestamp_->assign(ts.data(), ts.size());
          }
        }
        return false;

      case kTypeDeletion:
      case kTypeDeletionWithTimestamp:
      case kTypeSingleDeletion:
      case kTypeRangeDeletion:
        // TODO(noetzli): Verify correctness once merge of single-deletes
        // is supported
        assert(state_ == kNotFound || state_ == kMerge);
        if (kNotFound == state_) {
          state_ = kDeleted;
        } else if (kMerge == state_) {
          state_ = kFound;
          Merge(nullptr);
          // If do_merge_ = false then the current value shouldn't be part of
          // merge_context_->operand_list
        }
        return false;

      case kTypeMerge:
        assert(state_ == kNotFound || state_ == kMerge);
        state_ = kMerge;
        // value_pinner is not set from plain_table_reader.cc for example.
        push_operand(value, value_pinner);
        if (do_merge_ && merge_operator_ != nullptr &&
            merge_operator_->ShouldMerge(
                merge_context_->GetOperandsDirectionBackward())) {
          state_ = kFound;
          Merge(nullptr);
          return false;
        }
        return true;

      default:
        assert(false);
        break;
    }
  }

  // state_ could be Corrupt, merge or notfound
  return false;
}