diff options
author | Viktor TrĂ³n <viktor.tron@gmail.com> | 2018-10-03 20:59:41 +0800 |
---|---|---|
committer | GitHub <noreply@github.com> | 2018-10-03 20:59:41 +0800 |
commit | e5677114dc7461fe39ebe353a4657aa4cb03fde4 (patch) | |
tree | 8605f9a8b726b158fd01b4befced1e3ba92ca1f9 /swarm/storage/feed/update.go | |
parent | 303b99663e963a520aaa44eca68e042d9fe230af (diff) | |
parent | de01178c18766b9f744acc94fe2b96804f998e40 (diff) | |
download | dexon-e5677114dc7461fe39ebe353a4657aa4cb03fde4.tar dexon-e5677114dc7461fe39ebe353a4657aa4cb03fde4.tar.gz dexon-e5677114dc7461fe39ebe353a4657aa4cb03fde4.tar.bz2 dexon-e5677114dc7461fe39ebe353a4657aa4cb03fde4.tar.lz dexon-e5677114dc7461fe39ebe353a4657aa4cb03fde4.tar.xz dexon-e5677114dc7461fe39ebe353a4657aa4cb03fde4.tar.zst dexon-e5677114dc7461fe39ebe353a4657aa4cb03fde4.zip |
Merge pull request #17796 from epiclabs-io/mru-feeds
swarm/storage/feeds: Renamed MRU to Swarm Feeds
Diffstat (limited to 'swarm/storage/feed/update.go')
-rw-r--r-- | swarm/storage/feed/update.go | 132 |
1 files changed, 132 insertions, 0 deletions
diff --git a/swarm/storage/feed/update.go b/swarm/storage/feed/update.go new file mode 100644 index 000000000..627a537d1 --- /dev/null +++ b/swarm/storage/feed/update.go @@ -0,0 +1,132 @@ +// 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 feed + +import ( + "fmt" + "strconv" + + "github.com/ethereum/go-ethereum/swarm/chunk" +) + +// ProtocolVersion defines the current version of the protocol that will be included in each update message +const ProtocolVersion uint8 = 0 + +const headerLength = 8 + +// Header defines a update message header including a protocol version byte +type Header struct { + Version uint8 // Protocol version + Padding [headerLength - 1]uint8 // reserved for future use +} + +// Update encapsulates the information sent as part of a feed update +type Update struct { + Header Header // + ID // Feed Update identifying information + data []byte // actual data payload +} + +const minimumUpdateDataLength = idLength + headerLength + 1 +const maxUpdateDataLength = chunk.DefaultSize - signatureLength - idLength - headerLength + +// binaryPut serializes the feed update information into the given slice +func (r *Update) binaryPut(serializedData []byte) error { + datalength := len(r.data) + if datalength == 0 { + return NewError(ErrInvalidValue, "a feed update must contain data") + } + + if datalength > maxUpdateDataLength { + return NewErrorf(ErrInvalidValue, "feed update data is too big (length=%d). Max length=%d", datalength, maxUpdateDataLength) + } + + if len(serializedData) != r.binaryLength() { + return NewErrorf(ErrInvalidValue, "slice passed to putBinary must be of exact size. Expected %d bytes", r.binaryLength()) + } + + var cursor int + // serialize Header + serializedData[cursor] = r.Header.Version + copy(serializedData[cursor+1:headerLength], r.Header.Padding[:headerLength-1]) + cursor += headerLength + + // serialize ID + if err := r.ID.binaryPut(serializedData[cursor : cursor+idLength]); err != nil { + return err + } + cursor += idLength + + // add the data + copy(serializedData[cursor:], r.data) + cursor += datalength + + return nil +} + +// binaryLength returns the expected number of bytes this structure will take to encode +func (r *Update) binaryLength() int { + return idLength + headerLength + len(r.data) +} + +// binaryGet populates this instance from the information contained in the passed byte slice +func (r *Update) binaryGet(serializedData []byte) error { + if len(serializedData) < minimumUpdateDataLength { + return NewErrorf(ErrNothingToReturn, "chunk less than %d bytes cannot be a feed update chunk", minimumUpdateDataLength) + } + dataLength := len(serializedData) - idLength - headerLength + // at this point we can be satisfied that we have the correct data length to read + + var cursor int + + // deserialize Header + r.Header.Version = serializedData[cursor] // extract the protocol version + copy(r.Header.Padding[:headerLength-1], serializedData[cursor+1:headerLength]) // extract the padding + cursor += headerLength + + if err := r.ID.binaryGet(serializedData[cursor : cursor+idLength]); err != nil { + return err + } + cursor += idLength + + data := serializedData[cursor : cursor+dataLength] + cursor += dataLength + + // now that all checks have passed, copy data into structure + r.data = make([]byte, dataLength) + copy(r.data, data) + + return nil + +} + +// FromValues deserializes this instance from a string key-value store +// useful to parse query strings +func (r *Update) FromValues(values Values, data []byte) error { + r.data = data + version, _ := strconv.ParseUint(values.Get("protocolVersion"), 10, 32) + r.Header.Version = uint8(version) + return r.ID.FromValues(values) +} + +// AppendValues serializes this structure into the provided string key-value store +// useful to build query strings +func (r *Update) AppendValues(values Values) []byte { + r.ID.AppendValues(values) + values.Set("protocolVersion", fmt.Sprintf("%d", r.Header.Version)) + return r.data +} |