8dc3d77b59
Summary: This exposes CompressionManager and related classes to the public API and adds `ColumnFamilyOptions::compression_manager` for tying a custom compression strategy to a column family. At the moment, this does not support custom/pluggable compression algorithms, just custom strategies around the built-in algorithms, e.g. which compression to use when and where. A large part of the change is moving code from internal compression.h to a new public header advanced_compression.h, with some minor changes: * `Decompressor::ExtractUncompressedSize()` is out-of-lined * CompressionManager inherits Customizable and some related changes to members of CompressionManager are made. (Core functionality of CompressionManager is unchanged.) This depends on a smart pointer I'm calling `ManagedPtr` which I'm adding to data_structure.h. Additionally, advanced_compression.h gets CompressorWrapper and CompressionManagerWrapper as building blocks for overriding aspects of compression strategy while leveraging existing compression algorithms / schemas. Some pieces needed to support the `compression_manager` option and rudimentary Customizable implementation are included. More work will be needed to make this general and well-behaved (see e.g. https://github.com/facebook/rocksdb/issues/8641; I still hit inscrutible problems every time I touch Customizable). I'll add a release note for the experimental feature once pluggable compression algorithms and more of the Customizable things are working. Pull Request resolved: https://github.com/facebook/rocksdb/pull/13626 Test Plan: Added a unit test demonstrating how a custom compressor can "bypass" or "reject" compressions. Expected next follow-up (probably someone else): use a custom CompressionManager/Compressor to replace the internal hack for testing mixed compressions. Reviewed By: hx235 Differential Revision: D75028850 Pulled By: pdillinger fbshipit-source-id: 8565bb8ba4b5fa923b1e29e76b4f7bb4faa42381
88 lines
3.1 KiB
C++
88 lines
3.1 KiB
C++
// 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 <initializer_list>
|
|
#include <memory>
|
|
#include <type_traits>
|
|
|
|
#include "rocksdb/rocksdb_namespace.h"
|
|
|
|
namespace ROCKSDB_NAMESPACE {
|
|
// The helper function to assert the move from dynamic_cast<> to
|
|
// static_cast<> is correct. This function is to deal with legacy code.
|
|
// It is not recommended to add new code to issue class casting. The preferred
|
|
// solution is to implement the functionality without a need of casting.
|
|
template <class DestClass, class SrcClass>
|
|
inline DestClass* static_cast_with_check(SrcClass* x) {
|
|
DestClass* ret = static_cast<DestClass*>(x);
|
|
#ifdef ROCKSDB_USE_RTTI
|
|
assert(ret == dynamic_cast<DestClass*>(x));
|
|
#endif
|
|
return ret;
|
|
}
|
|
|
|
template <class DestClass, class SrcClass>
|
|
inline std::shared_ptr<DestClass> static_cast_with_check(
|
|
std::shared_ptr<SrcClass>&& x) {
|
|
#if defined(ROCKSDB_USE_RTTI) && !defined(NDEBUG)
|
|
auto orig_raw = x.get();
|
|
#endif
|
|
auto ret = std::static_pointer_cast<DestClass>(std::move(x));
|
|
#if defined(ROCKSDB_USE_RTTI) && !defined(NDEBUG)
|
|
assert(ret.get() == dynamic_cast<DestClass*>(orig_raw));
|
|
#endif
|
|
return ret;
|
|
}
|
|
|
|
// A wrapper around static_cast for lossless conversion between integral
|
|
// types, including enum types. For example, this can be used for converting
|
|
// between signed/unsigned or enum type and underlying type without fear of
|
|
// stripping away data, now or in the future.
|
|
template <typename To, typename From>
|
|
inline To lossless_cast(From x) {
|
|
using FromValue = typename std::remove_reference<From>::type;
|
|
static_assert(
|
|
std::is_integral<FromValue>::value || std::is_enum<FromValue>::value,
|
|
"Only works on integral types");
|
|
static_assert(std::is_integral<To>::value || std::is_enum<To>::value,
|
|
"Only works on integral types");
|
|
static_assert(sizeof(To) >= sizeof(FromValue), "Must be lossless");
|
|
return static_cast<To>(x);
|
|
}
|
|
|
|
// For disambiguating a potentially heterogeneous aggregate as a homogeneous
|
|
// initializer list. E.g. might be able to write List({x, y}) in some cases
|
|
// instead of std::vector<const Widget&>({x, y}).
|
|
template <typename T>
|
|
inline const std::initializer_list<T>& List(
|
|
const std::initializer_list<T>& list) {
|
|
return list;
|
|
}
|
|
|
|
// UnownedPtr<T> is useful as an efficient "optional reference" that can't
|
|
// be accidentally converted to std::shared_ptr<T> nor std::unique_ptr<T>.
|
|
template <typename T>
|
|
class UnownedPtr {
|
|
public:
|
|
UnownedPtr() = default;
|
|
UnownedPtr(std::nullptr_t) {}
|
|
UnownedPtr(T* ptr) : ptr_(ptr) {}
|
|
UnownedPtr(const UnownedPtr&) = default;
|
|
UnownedPtr(UnownedPtr&&) = default;
|
|
UnownedPtr& operator=(const UnownedPtr&) = default;
|
|
UnownedPtr& operator=(UnownedPtr&&) = default;
|
|
|
|
T* get() const { return ptr_; }
|
|
T* operator->() const { return ptr_; }
|
|
T& operator*() const { return *ptr_; }
|
|
operator bool() const { return ptr_ != nullptr; }
|
|
|
|
private:
|
|
T* ptr_ = nullptr;
|
|
};
|
|
|
|
} // namespace ROCKSDB_NAMESPACE
|