118 lines
4.2 KiB
Go
118 lines
4.2 KiB
Go
// Copyright 2018 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 mru
|
|
|
|
import (
|
|
"encoding/binary"
|
|
"hash"
|
|
|
|
"github.com/ethereum/go-ethereum/swarm/storage"
|
|
)
|
|
|
|
// LookupParams is used to specify constraints when performing an update lookup
|
|
// Limit defines whether or not the lookup should be limited
|
|
// If Limit is set to true then Max defines the amount of hops that can be performed
|
|
type LookupParams struct {
|
|
UpdateLookup
|
|
Limit uint32
|
|
}
|
|
|
|
// RootAddr returns the metadata chunk address
|
|
func (r *LookupParams) RootAddr() storage.Address {
|
|
return r.rootAddr
|
|
}
|
|
|
|
func NewLookupParams(rootAddr storage.Address, period, version uint32, limit uint32) *LookupParams {
|
|
return &LookupParams{
|
|
UpdateLookup: UpdateLookup{
|
|
period: period,
|
|
version: version,
|
|
rootAddr: rootAddr,
|
|
},
|
|
Limit: limit,
|
|
}
|
|
}
|
|
|
|
// LookupLatest generates lookup parameters that look for the latest version of a resource
|
|
func LookupLatest(rootAddr storage.Address) *LookupParams {
|
|
return NewLookupParams(rootAddr, 0, 0, 0)
|
|
}
|
|
|
|
// LookupLatestVersionInPeriod generates lookup parameters that look for the latest version of a resource in a given period
|
|
func LookupLatestVersionInPeriod(rootAddr storage.Address, period uint32) *LookupParams {
|
|
return NewLookupParams(rootAddr, period, 0, 0)
|
|
}
|
|
|
|
// LookupVersion generates lookup parameters that look for a specific version of a resource
|
|
func LookupVersion(rootAddr storage.Address, period, version uint32) *LookupParams {
|
|
return NewLookupParams(rootAddr, period, version, 0)
|
|
}
|
|
|
|
// UpdateLookup represents the components of a resource update search key
|
|
type UpdateLookup struct {
|
|
period uint32
|
|
version uint32
|
|
rootAddr storage.Address
|
|
}
|
|
|
|
// 4 bytes period
|
|
// 4 bytes version
|
|
// storage.Keylength for rootAddr
|
|
const updateLookupLength = 4 + 4 + storage.AddressLength
|
|
|
|
// UpdateAddr calculates the resource update chunk address corresponding to this lookup key
|
|
func (u *UpdateLookup) UpdateAddr() (updateAddr storage.Address) {
|
|
serializedData := make([]byte, updateLookupLength)
|
|
u.binaryPut(serializedData)
|
|
hasher := hashPool.Get().(hash.Hash)
|
|
defer hashPool.Put(hasher)
|
|
hasher.Reset()
|
|
hasher.Write(serializedData)
|
|
return hasher.Sum(nil)
|
|
}
|
|
|
|
// binaryPut serializes this UpdateLookup instance into the provided slice
|
|
func (u *UpdateLookup) binaryPut(serializedData []byte) error {
|
|
if len(serializedData) != updateLookupLength {
|
|
return NewErrorf(ErrInvalidValue, "Incorrect slice size to serialize UpdateLookup. Expected %d, got %d", updateLookupLength, len(serializedData))
|
|
}
|
|
if len(u.rootAddr) != storage.AddressLength {
|
|
return NewError(ErrInvalidValue, "UpdateLookup.binaryPut called without rootAddr set")
|
|
}
|
|
binary.LittleEndian.PutUint32(serializedData[:4], u.period)
|
|
binary.LittleEndian.PutUint32(serializedData[4:8], u.version)
|
|
copy(serializedData[8:], u.rootAddr[:])
|
|
return nil
|
|
}
|
|
|
|
// binaryLength returns the expected size of this structure when serialized
|
|
func (u *UpdateLookup) binaryLength() int {
|
|
return updateLookupLength
|
|
}
|
|
|
|
// binaryGet restores the current instance from the information contained in the passed slice
|
|
func (u *UpdateLookup) binaryGet(serializedData []byte) error {
|
|
if len(serializedData) != updateLookupLength {
|
|
return NewErrorf(ErrInvalidValue, "Incorrect slice size to read UpdateLookup. Expected %d, got %d", updateLookupLength, len(serializedData))
|
|
}
|
|
u.period = binary.LittleEndian.Uint32(serializedData[:4])
|
|
u.version = binary.LittleEndian.Uint32(serializedData[4:8])
|
|
u.rootAddr = storage.Address(make([]byte, storage.AddressLength))
|
|
copy(u.rootAddr[:], serializedData[8:])
|
|
return nil
|
|
}
|