From e6918187568dbd01842d8d1d2c808ce16a894239 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sun, 21 Apr 2024 13:54:28 +0200 Subject: Adding upstream version 18.2.2. Signed-off-by: Daniel Baumann --- src/rocksdb/db/read_callback.h | 54 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 54 insertions(+) create mode 100644 src/rocksdb/db/read_callback.h (limited to 'src/rocksdb/db/read_callback.h') diff --git a/src/rocksdb/db/read_callback.h b/src/rocksdb/db/read_callback.h new file mode 100644 index 000000000..c042352db --- /dev/null +++ b/src/rocksdb/db/read_callback.h @@ -0,0 +1,54 @@ +// 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 "db/dbformat.h" +#include "rocksdb/types.h" + +namespace ROCKSDB_NAMESPACE { + +class ReadCallback { + public: + explicit ReadCallback(SequenceNumber last_visible_seq) + : max_visible_seq_(last_visible_seq) {} + ReadCallback(SequenceNumber last_visible_seq, SequenceNumber min_uncommitted) + : max_visible_seq_(last_visible_seq), min_uncommitted_(min_uncommitted) {} + + virtual ~ReadCallback() {} + + // Will be called to see if the seq number visible; if not it moves on to + // the next seq number. + virtual bool IsVisibleFullCheck(SequenceNumber seq) = 0; + + inline bool IsVisible(SequenceNumber seq) { + assert(min_uncommitted_ > 0); + assert(min_uncommitted_ >= kMinUnCommittedSeq); + if (seq < min_uncommitted_) { // handles seq == 0 as well + assert(seq <= max_visible_seq_); + return true; + } else if (max_visible_seq_ < seq) { + assert(seq != 0); + return false; + } else { + assert(seq != 0); // already handled in the first if-then clause + return IsVisibleFullCheck(seq); + } + } + + inline SequenceNumber max_visible_seq() { return max_visible_seq_; } + + // Refresh to a more recent visible seq + virtual void Refresh(SequenceNumber seq) { max_visible_seq_ = seq; } + + protected: + // The max visible seq, it is usually the snapshot but could be larger if + // transaction has its own writes written to db. + SequenceNumber max_visible_seq_ = kMaxSequenceNumber; + // Any seq less than min_uncommitted_ is committed. + const SequenceNumber min_uncommitted_ = kMinUnCommittedSeq; +}; + +} // namespace ROCKSDB_NAMESPACE -- cgit v1.2.3