Adding upstream version 14.2.21.upstream/14.2.21upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 115 insertions, 0 deletions

diff --git a/src/rocksdb/table/table_reader.h b/src/rocksdb/table/table_reader.h
new file mode 100644
index 00000000..a5f15e13
--- /dev/null
+++ b/src/rocksdb/table/table_reader.h
@@ -0,0 +1,115 @@
+//  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).
+//
+// 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.
+
+#pragma once
+#include <memory>
+#include "db/range_tombstone_fragmenter.h"
+#include "rocksdb/slice_transform.h"
+#include "table/internal_iterator.h"
+
+namespace rocksdb {
+
+class Iterator;
+struct ParsedInternalKey;
+class Slice;
+class Arena;
+struct ReadOptions;
+struct TableProperties;
+class GetContext;
+
+// A Table is a sorted map from strings to strings.  Tables are
+// immutable and persistent.  A Table may be safely accessed from
+// multiple threads without external synchronization.
+class TableReader {
+ public:
+  virtual ~TableReader() {}
+
+  // Returns a new iterator over the table contents.
+  // The result of NewIterator() is initially invalid (caller must
+  // call one of the Seek methods on the iterator before using it).
+  // arena: If not null, the arena needs to be used to allocate the Iterator.
+  //        When destroying the iterator, the caller will not call "delete"
+  //        but Iterator::~Iterator() directly. The destructor needs to destroy
+  //        all the states but those allocated in arena.
+  // skip_filters: disables checking the bloom filters even if they exist. This
+  //               option is effective only for block-based table format.
+  virtual InternalIterator* NewIterator(const ReadOptions&,
+                                        const SliceTransform* prefix_extractor,
+                                        Arena* arena = nullptr,
+                                        bool skip_filters = false,
+                                        bool for_compaction = false) = 0;
+
+  virtual FragmentedRangeTombstoneIterator* NewRangeTombstoneIterator(
+      const ReadOptions& /*read_options*/) {
+    return nullptr;
+  }
+
+  // Given a key, return an approximate byte offset in the file where
+  // the data for that key begins (or would begin if the key were
+  // present in the file).  The returned value is in terms of file
+  // bytes, and so includes effects like compression of the underlying data.
+  // E.g., the approximate offset of the last key in the table will
+  // be close to the file length.
+  virtual uint64_t ApproximateOffsetOf(const Slice& key) = 0;
+
+  // Set up the table for Compaction. Might change some parameters with
+  // posix_fadvise
+  virtual void SetupForCompaction() = 0;
+
+  virtual std::shared_ptr<const TableProperties> GetTableProperties() const = 0;
+
+  // Prepare work that can be done before the real Get()
+  virtual void Prepare(const Slice& /*target*/) {}
+
+  // Report an approximation of how much memory has been used.
+  virtual size_t ApproximateMemoryUsage() const = 0;
+
+  // Calls get_context->SaveValue() repeatedly, starting with
+  // the entry found after a call to Seek(key), until it returns false.
+  // May not make such a call if filter policy says that key is not present.
+  //
+  // get_context->MarkKeyMayExist needs to be called when it is configured to be
+  // memory only and the key is not found in the block cache.
+  //
+  // readOptions is the options for the read
+  // key is the key to search for
+  // skip_filters: disables checking the bloom filters even if they exist. This
+  //               option is effective only for block-based table format.
+  virtual Status Get(const ReadOptions& readOptions, const Slice& key,
+                     GetContext* get_context,
+                     const SliceTransform* prefix_extractor,
+                     bool skip_filters = false) = 0;
+
+  // Prefetch data corresponding to a give range of keys
+  // Typically this functionality is required for table implementations that
+  // persists the data on a non volatile storage medium like disk/SSD
+  virtual Status Prefetch(const Slice* begin = nullptr,
+                          const Slice* end = nullptr) {
+    (void) begin;
+    (void) end;
+    // Default implementation is NOOP.
+    // The child class should implement functionality when applicable
+    return Status::OK();
+  }
+
+  // convert db file to a human readable form
+  virtual Status DumpTable(WritableFile* /*out_file*/,
+                           const SliceTransform* /*prefix_extractor*/) {
+    return Status::NotSupported("DumpTable() not supported");
+  }
+
+  // check whether there is corruption in this db file
+  virtual Status VerifyChecksum() {
+    return Status::NotSupported("VerifyChecksum() not supported");
+  }
+
+  virtual void Close() {}
+};
+
+}  // namespace rocksdb