332 lines
13 KiB
C++
332 lines
13 KiB
C++
/*
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* KeyBackedTypes.h
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*
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* This source file is part of the FoundationDB open source project
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*
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* Copyright 2013-2018 Apple Inc. and the FoundationDB project authors
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#pragma once
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#include <utility>
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#include <vector>
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#include "ReadYourWrites.h"
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#include "Subspace.h"
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#include "flow/genericactors.actor.h"
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// Codec is a utility struct to convert a type to and from a Tuple. It is used by the template
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// classes below like KeyBackedProperty and KeyBackedMap to convert key parts and values
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// from various types to Value strings and back.
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// New types can be supported either by writing a new specialization or adding these
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// methods to the type so that the default specialization can be used:
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// static T T::unpack(Tuple const &t)
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// Tuple T::pack() const
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// Since Codec is a struct, partial specialization can be used, such as the std::pair
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// partial specialization below allowing any std::pair<T1,T2> where T1 and T2 are already
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// supported by Codec.
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template<typename T>
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struct Codec {
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static inline Tuple pack(T const &val) { return val.pack(); }
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static inline T unpack(Tuple const &t) { return T::unpack(t); }
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};
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// If T is Tuple then conversion is simple.
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template<> inline Tuple Codec<Tuple>::pack(Tuple const &val) { return val; }
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template<> inline Tuple Codec<Tuple>::unpack(Tuple const &val) { return val; }
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template<> inline Tuple Codec<int64_t>::pack(int64_t const &val) { return Tuple().append(val); }
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template<> inline int64_t Codec<int64_t>::unpack(Tuple const &val) { return val.getInt(0); }
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template<> inline Tuple Codec<bool>::pack(bool const &val) { return Tuple().append(val ? 1 : 0); }
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template<> inline bool Codec<bool>::unpack(Tuple const &val) { return val.getInt(0) == 1; }
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template<> inline Tuple Codec<Standalone<StringRef>>::pack(Standalone<StringRef> const &val) { return Tuple().append(val); }
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template<> inline Standalone<StringRef> Codec<Standalone<StringRef>>::unpack(Tuple const &val) { return val.getString(0); }
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template<> inline Tuple Codec<UID>::pack(UID const &val) { return Codec<Standalone<StringRef>>::pack(BinaryWriter::toValue<UID>(val, Unversioned())); }
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template<> inline UID Codec<UID>::unpack(Tuple const &val) { return BinaryReader::fromStringRef<UID>(Codec<Standalone<StringRef>>::unpack(val), Unversioned()); }
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// This is backward compatible with Codec<Standalone<StringRef>>
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template<> inline Tuple Codec<std::string>::pack(std::string const &val) { return Tuple().append(StringRef(val)); }
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template<> inline std::string Codec<std::string>::unpack(Tuple const &val) { return val.getString(0).toString(); }
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// Partial specialization to cover all std::pairs as long as the component types are Codec compatible
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template<typename First, typename Second>
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struct Codec<std::pair<First, Second>> {
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static Tuple pack(typename std::pair<First, Second> const &val) { return Tuple().append(Codec<First>::pack(val.first)).append(Codec<Second>::pack(val.second)); }
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static std::pair<First, Second> unpack(Tuple const &t) {
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ASSERT(t.size() == 2);
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return {Codec<First>::unpack(t.subTuple(0, 1)), Codec<Second>::unpack(t.subTuple(1, 2))};
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}
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};
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template<typename T>
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struct Codec<std::vector<T>> {
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static Tuple pack(typename std::vector<T> const &val) {
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Tuple t;
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for (T item : val) {
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Tuple itemTuple = Codec<T>::pack(item);
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// fdbclient doesn't support nested tuples yet. For now, flatten the tuple into StringRef
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t.append(itemTuple.pack());
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}
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return t;
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}
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static std::vector<T> unpack(Tuple const &t) {
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std::vector<T> v;
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for (int i = 0; i < t.size(); i++) {
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Tuple itemTuple = Tuple::unpack(t.getString(i));
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v.push_back(Codec<T>::unpack(itemTuple));
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}
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return v;
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}
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};
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template<> inline Tuple Codec<KeyRange>::pack(KeyRange const &val) { return Tuple().append(val.begin).append(val.end); }
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template<> inline KeyRange Codec<KeyRange>::unpack(Tuple const &val) { return KeyRangeRef(val.getString(0), val.getString(1)); }
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// Convenient read/write access to a single value of type T stored at key
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// Even though 'this' is not actually mutated, methods that change the db key are not const.
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template <typename T>
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class KeyBackedProperty {
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public:
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KeyBackedProperty(KeyRef key) : key(key) {}
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Future<Optional<T>> get(Reference<ReadYourWritesTransaction> tr, bool snapshot = false) const {
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return map(tr->get(key, snapshot), [](Optional<Value> const &val) -> Optional<T> {
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if(val.present())
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return Codec<T>::unpack(Tuple::unpack(val.get()));
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return {};
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});
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}
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// Get property's value or defaultValue if it doesn't exist
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Future<T> getD(Reference<ReadYourWritesTransaction> tr, bool snapshot = false, T defaultValue = T()) const {
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return map(get(tr, snapshot), [=](Optional<T> val) -> T { return val.present() ? val.get() : defaultValue; });
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}
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// Get property's value or throw error if it doesn't exist
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Future<T> getOrThrow(Reference<ReadYourWritesTransaction> tr, bool snapshot = false, Error err = key_not_found()) const {
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auto keyCopy = key;
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auto backtrace = platform::get_backtrace();
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return map(get(tr, snapshot), [=](Optional<T> val) -> T {
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if (!val.present()) {
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TraceEvent(SevInfo, "KeyBackedProperty_keyNotFound")
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.detail("key", printable(keyCopy))
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.detail("err", err.code())
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.detail("parentTrace", backtrace.c_str());
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throw err;
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}
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return val.get();
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});
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}
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Future<Optional<T>> get(Database cx, bool snapshot = false) const {
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auto © = *this;
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return runRYWTransaction(cx, [=](Reference<ReadYourWritesTransaction> tr) {
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tr->setOption(FDBTransactionOptions::ACCESS_SYSTEM_KEYS);
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tr->setOption(FDBTransactionOptions::LOCK_AWARE);
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return copy.get(tr, snapshot);
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});
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}
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Future<T> getD(Database cx, bool snapshot = false, T defaultValue = T()) const {
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auto © = *this;
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return runRYWTransaction(cx, [=](Reference<ReadYourWritesTransaction> tr) {
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tr->setOption(FDBTransactionOptions::ACCESS_SYSTEM_KEYS);
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tr->setOption(FDBTransactionOptions::LOCK_AWARE);
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return copy.getD(tr, snapshot, defaultValue);
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});
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}
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Future<T> getOrThrow(Database cx, bool snapshot = false, Error err = key_not_found()) const {
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auto © = *this;
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return runRYWTransaction(cx, [=](Reference<ReadYourWritesTransaction> tr) {
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tr->setOption(FDBTransactionOptions::ACCESS_SYSTEM_KEYS);
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tr->setOption(FDBTransactionOptions::LOCK_AWARE);
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return copy.getOrThrow(tr, snapshot, err);
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});
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}
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void set(Reference<ReadYourWritesTransaction> tr, T const &val) {
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return tr->set(key, Codec<T>::pack(val).pack());
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}
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Future<Void> set(Database cx, T const &val) {
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auto _key = key;
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Value _val = Codec<T>::pack(val).pack();
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return runRYWTransaction(cx, [_key, _val](Reference<ReadYourWritesTransaction> tr) {
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tr->setOption(FDBTransactionOptions::ACCESS_SYSTEM_KEYS);
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tr->setOption(FDBTransactionOptions::LOCK_AWARE);
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tr->set(_key, _val);
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return Future<Void>(Void());
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});
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}
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void clear(Reference<ReadYourWritesTransaction> tr) {
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return tr->clear(key);
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}
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Key key;
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};
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// This is just like KeyBackedProperty but instead of using Codec for conversion to/from values it
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// uses BinaryReader and BinaryWriter. This enables allows atomic ops with integer types, and also
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// allows reading and writing of existing keys which use BinaryReader/Writer.
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template <typename T>
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class KeyBackedBinaryValue {
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public:
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KeyBackedBinaryValue(KeyRef key) : key(key) {}
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Future<Optional<T>> get(Reference<ReadYourWritesTransaction> tr, bool snapshot = false) const {
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return map(tr->get(key, snapshot), [](Optional<Value> const &val) -> Optional<T> {
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if(val.present())
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return BinaryReader::fromStringRef<T>(val.get(), Unversioned());
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return {};
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});
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}
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// Get property's value or defaultValue if it doesn't exist
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Future<T> getD(Reference<ReadYourWritesTransaction> tr, bool snapshot = false, T defaultValue = T()) const {
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return map(get(tr, false), [=](Optional<T> val) -> T { return val.present() ? val.get() : defaultValue; });
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}
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void set(Reference<ReadYourWritesTransaction> tr, T const &val) {
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return tr->set(key, BinaryWriter::toValue<T>(val, Unversioned()));
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}
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void atomicOp(Reference<ReadYourWritesTransaction> tr, T const &val, MutationRef::Type type) {
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return tr->atomicOp(key, BinaryWriter::toValue<T>(val, Unversioned()), type);
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}
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void clear(Reference<ReadYourWritesTransaction> tr) {
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return tr->clear(key);
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}
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Key key;
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};
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// Convenient read/write access to a sorted map of KeyType to ValueType that has key as its prefix
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// Even though 'this' is not actually mutated, methods that change db keys are not const.
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template <typename _KeyType, typename _ValueType>
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class KeyBackedMap {
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public:
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KeyBackedMap(KeyRef key) : space(key) {}
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typedef _KeyType KeyType;
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typedef _ValueType ValueType;
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typedef std::pair<KeyType, ValueType> PairType;
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typedef std::vector<PairType> PairsType;
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// If end is not present one key past the end of the map is used.
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Future<PairsType> getRange(Reference<ReadYourWritesTransaction> tr, KeyType const &begin, Optional<KeyType> const &end, int limit, bool snapshot = false, bool reverse = false) const {
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Subspace s = space; // 'this' could be invalid inside lambda
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Key endKey = end.present() ? s.pack(Codec<KeyType>::pack(end.get())) : space.range().end;
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return map(tr->getRange(KeyRangeRef(s.pack(Codec<KeyType>::pack(begin)), endKey), GetRangeLimits(limit), snapshot, reverse),
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[s] (Standalone<RangeResultRef> const &kvs) -> PairsType {
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PairsType results;
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for(int i = 0; i < kvs.size(); ++i) {
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KeyType key = Codec<KeyType>::unpack(s.unpack(kvs[i].key));
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ValueType val = Codec<ValueType>::unpack(Tuple::unpack(kvs[i].value));
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results.push_back(PairType(key, val));
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}
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return results;
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});
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}
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Future<Optional<ValueType>> get(Reference<ReadYourWritesTransaction> tr, KeyType const &key, bool snapshot = false) const {
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return map(tr->get(space.pack(Codec<KeyType>::pack(key)), snapshot), [](Optional<Value> const &val) -> Optional<ValueType> {
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if(val.present())
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return Codec<ValueType>::unpack(Tuple::unpack(val.get()));
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return {};
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});
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}
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// Returns a Property that can be get/set that represents key's entry in this this.
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KeyBackedProperty<ValueType> getProperty(KeyType const &key) const {
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return space.pack(Codec<KeyType>::pack(key));
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}
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// Returns the expectedSize of the set key
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int set(Reference<ReadYourWritesTransaction> tr, KeyType const &key, ValueType const &val) {
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Key k = space.pack(Codec<KeyType>::pack(key));
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Value v = Codec<ValueType>::pack(val).pack();
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tr->set(k, v);
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return k.expectedSize() + v.expectedSize();
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}
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void erase(Reference<ReadYourWritesTransaction> tr, KeyType const &key) {
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return tr->clear(space.pack(Codec<KeyType>::pack(key)));
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}
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void erase(Reference<ReadYourWritesTransaction> tr, KeyType const &begin, KeyType const &end) {
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return tr->clear(KeyRangeRef(space.pack(Codec<KeyType>::pack(begin)), space.pack(Codec<KeyType>::pack(end))));
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}
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void clear(Reference<ReadYourWritesTransaction> tr) {
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return tr->clear(space.range());
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}
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Subspace space;
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};
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template <typename _ValueType>
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class KeyBackedSet {
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public:
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KeyBackedSet(KeyRef key) : space(key) {}
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typedef _ValueType ValueType;
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typedef std::vector<ValueType> Values;
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// If end is not present one key past the end of the map is used.
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Future<Values> getRange(Reference<ReadYourWritesTransaction> tr, ValueType const &begin, Optional<ValueType> const &end, int limit, bool snapshot = false) const {
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Subspace s = space; // 'this' could be invalid inside lambda
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Key endKey = end.present() ? s.pack(Codec<ValueType>::pack(end.get())) : space.range().end;
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return map(tr->getRange(KeyRangeRef(s.pack(Codec<ValueType>::pack(begin)), endKey), GetRangeLimits(limit), snapshot),
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[s] (Standalone<RangeResultRef> const &kvs) -> Values {
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Values results;
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for(int i = 0; i < kvs.size(); ++i) {
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results.push_back(Codec<ValueType>::unpack(s.unpack(kvs[i].key)));
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}
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return results;
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});
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}
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Future<bool> exists(Reference<ReadYourWritesTransaction> tr, ValueType const &val, bool snapshot = false) const {
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return map(tr->get(space.pack(Codec<ValueType>::pack(val)), snapshot), [](Optional<Value> const &val) -> bool {
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return val.present();
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});
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}
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// Returns the expectedSize of the set key
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int insert(Reference<ReadYourWritesTransaction> tr, ValueType const &val) {
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Key k = space.pack(Codec<ValueType>::pack(val));
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tr->set(k, StringRef());
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return k.expectedSize();
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}
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void erase(Reference<ReadYourWritesTransaction> tr, ValueType const &val) {
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return tr->clear(space.pack(Codec<ValueType>::pack(val)));
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}
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void erase(Reference<ReadYourWritesTransaction> tr, ValueType const &begin, ValueType const &end) {
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return tr->clear(KeyRangeRef(space.pack(Codec<ValueType>::pack(begin)), space.pack(Codec<ValueType>::pack(end))));
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}
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void clear(Reference<ReadYourWritesTransaction> tr) {
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return tr->clear(space.range());
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}
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Subspace space;
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};
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