89 lines
3.2 KiB
Go
89 lines
3.2 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 mru
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import (
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"github.com/ethereum/go-ethereum/swarm/storage"
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)
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// updateHeader models the non-payload components of a Resource Update
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type updateHeader struct {
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UpdateLookup // UpdateLookup contains the information required to locate this resource (components of the search key used to find it)
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multihash bool // Whether the data in this Resource Update should be interpreted as multihash
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metaHash []byte // SHA3 hash of the metadata chunk (less ownerAddr). Used to prove ownerhsip of the resource.
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}
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const metaHashLength = storage.KeyLength
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// updateLookupLength bytes
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// 1 byte flags (multihash bool for now)
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// 32 bytes metaHash
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const updateHeaderLength = updateLookupLength + 1 + metaHashLength
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// binaryPut serializes the resource header information into the given slice
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func (h *updateHeader) binaryPut(serializedData []byte) error {
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if len(serializedData) != updateHeaderLength {
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return NewErrorf(ErrInvalidValue, "Incorrect slice size to serialize updateHeaderLength. Expected %d, got %d", updateHeaderLength, len(serializedData))
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}
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if len(h.metaHash) != metaHashLength {
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return NewError(ErrInvalidValue, "updateHeader.binaryPut called without metaHash set")
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}
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if err := h.UpdateLookup.binaryPut(serializedData[:updateLookupLength]); err != nil {
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return err
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}
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cursor := updateLookupLength
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copy(serializedData[cursor:], h.metaHash[:metaHashLength])
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cursor += metaHashLength
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var flags byte
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if h.multihash {
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flags |= 0x01
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}
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serializedData[cursor] = flags
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cursor++
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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 (h *updateHeader) binaryLength() int {
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return updateHeaderLength
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}
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// binaryGet restores the current updateHeader instance from the information contained in the passed slice
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func (h *updateHeader) binaryGet(serializedData []byte) error {
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if len(serializedData) != updateHeaderLength {
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return NewErrorf(ErrInvalidValue, "Incorrect slice size to read updateHeaderLength. Expected %d, got %d", updateHeaderLength, len(serializedData))
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}
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if err := h.UpdateLookup.binaryGet(serializedData[:updateLookupLength]); err != nil {
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return err
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}
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cursor := updateLookupLength
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h.metaHash = make([]byte, metaHashLength)
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copy(h.metaHash[:storage.KeyLength], serializedData[cursor:cursor+storage.KeyLength])
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cursor += metaHashLength
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flags := serializedData[cursor]
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cursor++
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h.multihash = flags&0x01 != 0
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return nil
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}
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