diff options
Diffstat (limited to 'swarm/storage/mru/updateheader.go')
-rw-r--r-- | swarm/storage/mru/updateheader.go | 88 |
1 files changed, 88 insertions, 0 deletions
diff --git a/swarm/storage/mru/updateheader.go b/swarm/storage/mru/updateheader.go new file mode 100644 index 000000000..3ac20c189 --- /dev/null +++ b/swarm/storage/mru/updateheader.go @@ -0,0 +1,88 @@ +// 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 ( + "github.com/ethereum/go-ethereum/swarm/storage" +) + +// updateHeader models the non-payload components of a Resource Update +type updateHeader struct { + UpdateLookup // UpdateLookup contains the information required to locate this resource (components of the search key used to find it) + multihash bool // Whether the data in this Resource Update should be interpreted as multihash + metaHash []byte // SHA3 hash of the metadata chunk (less ownerAddr). Used to prove ownerhsip of the resource. +} + +const metaHashLength = storage.KeyLength + +// updateLookupLength bytes +// 1 byte flags (multihash bool for now) +// 32 bytes metaHash +const updateHeaderLength = updateLookupLength + 1 + metaHashLength + +// binaryPut serializes the resource header information into the given slice +func (h *updateHeader) binaryPut(serializedData []byte) error { + if len(serializedData) != updateHeaderLength { + return NewErrorf(ErrInvalidValue, "Incorrect slice size to serialize updateHeaderLength. Expected %d, got %d", updateHeaderLength, len(serializedData)) + } + if len(h.metaHash) != metaHashLength { + return NewError(ErrInvalidValue, "updateHeader.binaryPut called without metaHash set") + } + if err := h.UpdateLookup.binaryPut(serializedData[:updateLookupLength]); err != nil { + return err + } + cursor := updateLookupLength + copy(serializedData[cursor:], h.metaHash[:metaHashLength]) + cursor += metaHashLength + + var flags byte + if h.multihash { + flags |= 0x01 + } + + serializedData[cursor] = flags + cursor++ + + return nil +} + +// binaryLength returns the expected size of this structure when serialized +func (h *updateHeader) binaryLength() int { + return updateHeaderLength +} + +// binaryGet restores the current updateHeader instance from the information contained in the passed slice +func (h *updateHeader) binaryGet(serializedData []byte) error { + if len(serializedData) != updateHeaderLength { + return NewErrorf(ErrInvalidValue, "Incorrect slice size to read updateHeaderLength. Expected %d, got %d", updateHeaderLength, len(serializedData)) + } + + if err := h.UpdateLookup.binaryGet(serializedData[:updateLookupLength]); err != nil { + return err + } + cursor := updateLookupLength + h.metaHash = make([]byte, metaHashLength) + copy(h.metaHash[:storage.KeyLength], serializedData[cursor:cursor+storage.KeyLength]) + cursor += metaHashLength + + flags := serializedData[cursor] + cursor++ + + h.multihash = flags&0x01 != 0 + + return nil +} |