plugeth/les/vflux/requests.go

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// Copyright 2021 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// The go-ethereum library is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// The go-ethereum library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
package vflux
import (
"errors"
"math"
"math/big"
"github.com/ethereum/go-ethereum/rlp"
)
var ErrNoReply = errors.New("no reply for given request")
const (
MaxRequestLength = 16 // max number of individual requests in a batch
CapacityQueryName = "cq"
CapacityQueryMaxLen = 16
)
type (
// Request describes a single vflux request inside a batch. Service and request
// type are identified by strings, parameters are RLP encoded.
Request struct {
Service, Name string
Params []byte
}
// Requests are a batch of vflux requests
Requests []Request
// Replies are the replies to a batch of requests
Replies [][]byte
// CapacityQueryReq is the encoding format of the capacity query
CapacityQueryReq struct {
Bias uint64 // seconds
AddTokens []IntOrInf
}
// CapacityQueryReq is the encoding format of the response to the capacity query
CapacityQueryReply []uint64
)
// Add encodes and adds a new request to the batch
func (r *Requests) Add(service, name string, val interface{}) (int, error) {
enc, err := rlp.EncodeToBytes(val)
if err != nil {
return -1, err
}
*r = append(*r, Request{
Service: service,
Name: name,
Params: enc,
})
return len(*r) - 1, nil
}
// Get decodes the reply to the i-th request in the batch
func (r Replies) Get(i int, val interface{}) error {
if i < 0 || i >= len(r) {
return ErrNoReply
}
return rlp.DecodeBytes(r[i], val)
}
const (
IntNonNegative = iota
IntNegative
IntPlusInf
IntMinusInf
)
// IntOrInf is the encoding format for arbitrary length signed integers that can also
// hold the values of +Inf or -Inf
type IntOrInf struct {
Type uint8
Value big.Int
}
// BigInt returns the value as a big.Int or panics if the value is infinity
func (i *IntOrInf) BigInt() *big.Int {
switch i.Type {
case IntNonNegative:
return new(big.Int).Set(&i.Value)
case IntNegative:
return new(big.Int).Neg(&i.Value)
case IntPlusInf:
panic(nil) // caller should check Inf() before trying to convert to big.Int
case IntMinusInf:
panic(nil)
}
return &big.Int{} // invalid type decodes to 0 value
}
// Inf returns 1 if the value is +Inf, -1 if it is -Inf, 0 otherwise
func (i *IntOrInf) Inf() int {
switch i.Type {
case IntPlusInf:
return 1
case IntMinusInf:
return -1
}
return 0 // invalid type decodes to 0 value
}
// Int64 limits the value between MinInt64 and MaxInt64 (even if it is +-Inf) and returns an int64 type
func (i *IntOrInf) Int64() int64 {
switch i.Type {
case IntNonNegative:
if i.Value.IsInt64() {
return i.Value.Int64()
} else {
return math.MaxInt64
}
case IntNegative:
if i.Value.IsInt64() {
return -i.Value.Int64()
} else {
return math.MinInt64
}
case IntPlusInf:
return math.MaxInt64
case IntMinusInf:
return math.MinInt64
}
return 0 // invalid type decodes to 0 value
}
// SetBigInt sets the value to the given big.Int
func (i *IntOrInf) SetBigInt(v *big.Int) {
if v.Sign() >= 0 {
i.Type = IntNonNegative
i.Value.Set(v)
} else {
i.Type = IntNegative
i.Value.Neg(v)
}
}
// SetInt64 sets the value to the given int64. Note that MaxInt64 translates to +Inf
// while MinInt64 translates to -Inf.
func (i *IntOrInf) SetInt64(v int64) {
if v >= 0 {
if v == math.MaxInt64 {
i.Type = IntPlusInf
} else {
i.Type = IntNonNegative
i.Value.SetInt64(v)
}
} else {
if v == math.MinInt64 {
i.Type = IntMinusInf
} else {
i.Type = IntNegative
i.Value.SetInt64(-v)
}
}
}
// SetInf sets the value to +Inf or -Inf
func (i *IntOrInf) SetInf(sign int) {
if sign == 1 {
i.Type = IntPlusInf
} else {
i.Type = IntMinusInf
}
}