github.com/FUSIONFoundation/efsn@v3.6.2-0.20200916075423-dbb5dd5d2cc7+incompatible/swarm/storage/mru/updateheader.go (about) 1 // Copyright 2018 The go-ethereum Authors 2 // This file is part of the go-ethereum library. 3 // 4 // The go-ethereum library is free software: you can redistribute it and/or modify 5 // it under the terms of the GNU Lesser General Public License as published by 6 // the Free Software Foundation, either version 3 of the License, or 7 // (at your option) any later version. 8 // 9 // The go-ethereum library is distributed in the hope that it will be useful, 10 // but WITHOUT ANY WARRANTY; without even the implied warranty of 11 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 12 // GNU Lesser General Public License for more details. 13 // 14 // You should have received a copy of the GNU Lesser General Public License 15 // along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>. 16 17 package mru 18 19 import ( 20 "github.com/FusionFoundation/efsn/swarm/storage" 21 ) 22 23 // updateHeader models the non-payload components of a Resource Update 24 type updateHeader struct { 25 UpdateLookup // UpdateLookup contains the information required to locate this resource (components of the search key used to find it) 26 multihash bool // Whether the data in this Resource Update should be interpreted as multihash 27 metaHash []byte // SHA3 hash of the metadata chunk (less ownerAddr). Used to prove ownerhsip of the resource. 28 } 29 30 const metaHashLength = storage.AddressLength 31 32 // updateLookupLength bytes 33 // 1 byte flags (multihash bool for now) 34 // 32 bytes metaHash 35 const updateHeaderLength = updateLookupLength + 1 + metaHashLength 36 37 // binaryPut serializes the resource header information into the given slice 38 func (h *updateHeader) binaryPut(serializedData []byte) error { 39 if len(serializedData) != updateHeaderLength { 40 return NewErrorf(ErrInvalidValue, "Incorrect slice size to serialize updateHeaderLength. Expected %d, got %d", updateHeaderLength, len(serializedData)) 41 } 42 if len(h.metaHash) != metaHashLength { 43 return NewError(ErrInvalidValue, "updateHeader.binaryPut called without metaHash set") 44 } 45 if err := h.UpdateLookup.binaryPut(serializedData[:updateLookupLength]); err != nil { 46 return err 47 } 48 cursor := updateLookupLength 49 copy(serializedData[cursor:], h.metaHash[:metaHashLength]) 50 cursor += metaHashLength 51 52 var flags byte 53 if h.multihash { 54 flags |= 0x01 55 } 56 57 serializedData[cursor] = flags 58 cursor++ 59 60 return nil 61 } 62 63 // binaryLength returns the expected size of this structure when serialized 64 func (h *updateHeader) binaryLength() int { 65 return updateHeaderLength 66 } 67 68 // binaryGet restores the current updateHeader instance from the information contained in the passed slice 69 func (h *updateHeader) binaryGet(serializedData []byte) error { 70 if len(serializedData) != updateHeaderLength { 71 return NewErrorf(ErrInvalidValue, "Incorrect slice size to read updateHeaderLength. Expected %d, got %d", updateHeaderLength, len(serializedData)) 72 } 73 74 if err := h.UpdateLookup.binaryGet(serializedData[:updateLookupLength]); err != nil { 75 return err 76 } 77 cursor := updateLookupLength 78 h.metaHash = make([]byte, metaHashLength) 79 copy(h.metaHash[:storage.AddressLength], serializedData[cursor:cursor+storage.AddressLength]) 80 cursor += metaHashLength 81 82 flags := serializedData[cursor] 83 cursor++ 84 85 h.multihash = flags&0x01 != 0 86 87 return nil 88 }