foundationdb/fdbclient/CommitTransaction.h

/*
 * CommitTransaction.h
 *
 * This source file is part of the FoundationDB open source project
 *
 * Copyright 2013-2018 Apple Inc. and the FoundationDB project authors
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#ifndef FLOW_FDBCLIENT_COMMITTRANSACTION_H
#define FLOW_FDBCLIENT_COMMITTRANSACTION_H
#pragma once

#include "fdbclient/FDBTypes.h"

static const char* typeString[] = { "SetValue",
	                                "ClearRange",
	                                "AddValue",
	                                "DebugKeyRange",
	                                "DebugKey",
	                                "NoOp",
	                                "And",
	                                "Or",
	                                "Xor",
	                                "AppendIfFits",
	                                "AvailableForReuse",
	                                "Reserved_For_LogProtocolMessage",
	                                "Max",
	                                "Min",
	                                "SetVersionstampedKey",
	                                "SetVersionstampedValue",
	                                "ByteMin",
	                                "ByteMax",
	                                "MinV2",
	                                "AndV2",
	                                "CompareAndClear"};

struct MutationRef { 
	static const int OVERHEAD_BYTES = 12; //12 is the size of Header in MutationList entries
	enum Type : uint8_t {
		SetValue = 0,
		ClearRange,
		AddValue,
		DebugKeyRange,
		DebugKey,
		NoOp,
		And,
		Or,
		Xor,
		AppendIfFits,
		AvailableForReuse,
		Reserved_For_LogProtocolMessage /* See fdbserver/LogProtocolMessage.h */,
		Max,
		Min,
		SetVersionstampedKey,
		SetVersionstampedValue,
		ByteMin,
		ByteMax,
		MinV2,
		AndV2,
		CompareAndClear,
		MAX_ATOMIC_OP
	};
	// This is stored this way for serialization purposes.
	uint8_t type;
	StringRef param1, param2;

	MutationRef() {}
	MutationRef( Type t, StringRef a, StringRef b ) : type(t), param1(a), param2(b) {}
	MutationRef( Arena& to, const MutationRef& from ) : type(from.type), param1( to, from.param1 ), param2( to, from.param2 ) {}
	int totalSize() const { return OVERHEAD_BYTES + param1.size() + param2.size(); } 
	int expectedSize() const { return param1.size() + param2.size(); }

	std::string toString() const {
		if (type < MutationRef::MAX_ATOMIC_OP) {
			return format("code: %s param1: %s param2: %s", typeString[type], printable(param1).c_str(), printable(param2).c_str());
		}
		else {
			return format("code: %s param1: %s param2: %s", "Invalid", printable(param1).c_str(), printable(param2).c_str());
		}
	}

	template <class Ar>
	void serialize( Ar& ar ) {
		serializer(ar, type, param1, param2);
	}

	// These masks define which mutation types have particular properties (they are used to implement isSingleKeyMutation() etc)
	enum {
		ATOMIC_MASK = (1 << AddValue) | (1 << And) | (1 << Or) | (1 << Xor) | (1 << AppendIfFits) | (1 << Max) |
		              (1 << Min) | (1 << SetVersionstampedKey) | (1 << SetVersionstampedValue) | (1 << ByteMin) |
		              (1 << ByteMax) | (1 << MinV2) | (1 << AndV2) | (1 << CompareAndClear),
		SINGLE_KEY_MASK = ATOMIC_MASK | (1 << SetValue),
		NON_ASSOCIATIVE_MASK = (1 << AddValue) | (1 << Or) | (1 << Xor) | (1 << Max) | (1 << Min) |
		                       (1 << SetVersionstampedKey) | (1 << SetVersionstampedValue) | (1 << MinV2) |
		                       (1 << CompareAndClear)
	};
};

// A 'single key mutation' is one which affects exactly the value of the key specified by its param1
static inline bool isSingleKeyMutation(MutationRef::Type type) {
	return (MutationRef::SINGLE_KEY_MASK & (1<<type)) != 0;
}

// Returns true if the given type can be safely cast to MutationRef::Type and used as a parameter to
// isSingleKeyMutation, isAtomicOp, etc.  It does NOT mean that the type is a valid type of a MutationRef in any
// particular context.
static inline bool isValidMutationType(uint32_t type) {
	return (type < MutationRef::MAX_ATOMIC_OP);
}

// An 'atomic operation' is a single key mutation which sets the key specified by its param1 to a 
//   nontrivial function of the previous value of the key and param2, and thus requires a 
//   read/modify/write to implement.  (Basically a single key mutation other than a set)
static inline bool isAtomicOp(MutationRef::Type mutationType) {
	return (MutationRef::ATOMIC_MASK & (1<<mutationType)) != 0;
}

// Returns true for operations which do not obey the associative law (i.e. a*(b*c) == (a*b)*c) in all cases
// unless a, b, and c have equal lengths, in which case even these operations are associative.
static inline bool isNonAssociativeOp(MutationRef::Type mutationType) {
	return (MutationRef::NON_ASSOCIATIVE_MASK & (1<<mutationType)) != 0;
}

struct CommitTransactionRef {
	CommitTransactionRef() : read_snapshot(0) {}
	CommitTransactionRef(Arena &a, const CommitTransactionRef &from)
	  : read_conflict_ranges(a, from.read_conflict_ranges),
		write_conflict_ranges(a, from.write_conflict_ranges),
		mutations(a, from.mutations),
		read_snapshot(from.read_snapshot) {
	}
	VectorRef< KeyRangeRef > read_conflict_ranges;
	VectorRef< KeyRangeRef > write_conflict_ranges;
	VectorRef< MutationRef > mutations;
	Version read_snapshot;

	template <class Ar>
	force_inline void serialize( Ar& ar ) {
		serializer(ar, read_conflict_ranges, write_conflict_ranges, mutations, read_snapshot);
	}

	// Convenience for internal code required to manipulate these without the Native API
	void set( Arena& arena, KeyRef const& key, ValueRef const& value ) {
		mutations.push_back_deep(arena, MutationRef(MutationRef::SetValue, key, value));
		write_conflict_ranges.push_back(arena, singleKeyRange(key, arena));
	}

	void clear( Arena& arena, KeyRangeRef const& keys ) {
		mutations.push_back_deep(arena, MutationRef(MutationRef::ClearRange, keys.begin, keys.end));
		write_conflict_ranges.push_back_deep(arena, keys);
	}

	size_t expectedSize() const {
		return read_conflict_ranges.expectedSize() + write_conflict_ranges.expectedSize() + mutations.expectedSize();
	}
};

bool debugMutation( const char* context, Version version, MutationRef const& m );
bool debugKeyRange( const char* context, Version version, KeyRangeRef const& keyRange );

#endif