124 lines
3.7 KiB
Go
124 lines
3.7 KiB
Go
// Copyright 2018 The go-ethereum Authors
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// This file is part of the go-ethereum library.
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//
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// The go-ethereum library is free software: you can redistribute it and/or modify
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// it under the terms of the GNU Lesser General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// The go-ethereum library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU Lesser General Public License for more details.
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//
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// You should have received a copy of the GNU Lesser General Public License
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// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
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package feed
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import (
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"fmt"
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"hash"
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"strconv"
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"github.com/ethereum/go-ethereum/common"
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"github.com/ethereum/go-ethereum/swarm/storage/feed/lookup"
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"github.com/ethereum/go-ethereum/swarm/storage"
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)
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// ID uniquely identifies an update on the network.
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type ID struct {
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Feed `json:"feed"`
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lookup.Epoch `json:"epoch"`
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}
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// ID layout:
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// Feed feedLength bytes
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// Epoch EpochLength
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const idLength = feedLength + lookup.EpochLength
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// Addr calculates the feed update chunk address corresponding to this ID
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func (u *ID) Addr() (updateAddr storage.Address) {
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serializedData := make([]byte, idLength)
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var cursor int
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u.Feed.binaryPut(serializedData[cursor : cursor+feedLength])
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cursor += feedLength
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eid := u.Epoch.ID()
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copy(serializedData[cursor:cursor+lookup.EpochLength], eid[:])
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hasher := hashPool.Get().(hash.Hash)
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defer hashPool.Put(hasher)
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hasher.Reset()
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hasher.Write(serializedData)
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return hasher.Sum(nil)
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}
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// binaryPut serializes this instance into the provided slice
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func (u *ID) binaryPut(serializedData []byte) error {
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if len(serializedData) != idLength {
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return NewErrorf(ErrInvalidValue, "Incorrect slice size to serialize ID. Expected %d, got %d", idLength, len(serializedData))
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}
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var cursor int
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if err := u.Feed.binaryPut(serializedData[cursor : cursor+feedLength]); err != nil {
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return err
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}
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cursor += feedLength
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epochBytes, err := u.Epoch.MarshalBinary()
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if err != nil {
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return err
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}
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copy(serializedData[cursor:cursor+lookup.EpochLength], epochBytes[:])
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cursor += lookup.EpochLength
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return nil
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}
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// binaryLength returns the expected size of this structure when serialized
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func (u *ID) binaryLength() int {
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return idLength
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}
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// binaryGet restores the current instance from the information contained in the passed slice
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func (u *ID) binaryGet(serializedData []byte) error {
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if len(serializedData) != idLength {
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return NewErrorf(ErrInvalidValue, "Incorrect slice size to read ID. Expected %d, got %d", idLength, len(serializedData))
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}
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var cursor int
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if err := u.Feed.binaryGet(serializedData[cursor : cursor+feedLength]); err != nil {
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return err
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}
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cursor += feedLength
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if err := u.Epoch.UnmarshalBinary(serializedData[cursor : cursor+lookup.EpochLength]); err != nil {
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return err
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}
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cursor += lookup.EpochLength
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return nil
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}
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// FromValues deserializes this instance from a string key-value store
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// useful to parse query strings
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func (u *ID) FromValues(values Values) error {
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level, _ := strconv.ParseUint(values.Get("level"), 10, 32)
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u.Epoch.Level = uint8(level)
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u.Epoch.Time, _ = strconv.ParseUint(values.Get("time"), 10, 64)
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if u.Feed.User == (common.Address{}) {
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return u.Feed.FromValues(values)
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}
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return nil
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}
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// AppendValues serializes this structure into the provided string key-value store
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// useful to build query strings
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func (u *ID) AppendValues(values Values) {
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values.Set("level", fmt.Sprintf("%d", u.Epoch.Level))
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values.Set("time", fmt.Sprintf("%d", u.Epoch.Time))
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u.Feed.AppendValues(values)
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}
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