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author | Javier Peletier <jm@epiclabs.io> | 2018-10-03 15:15:17 +0800 |
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committer | Javier Peletier <jm@epiclabs.io> | 2018-10-03 15:15:28 +0800 |
commit | de01178c18766b9f744acc94fe2b96804f998e40 (patch) | |
tree | b572a263ff660bd5ded343a5253f86f1f1145e46 /swarm/storage/feed/feed.go | |
parent | 696bc9b01ce0ed3347fa1bd64460ccc08091e90a (diff) | |
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swarm/storage/feed: Renamed package
Diffstat (limited to 'swarm/storage/feed/feed.go')
-rw-r--r-- | swarm/storage/feed/feed.go | 125 |
1 files changed, 125 insertions, 0 deletions
diff --git a/swarm/storage/feed/feed.go b/swarm/storage/feed/feed.go new file mode 100644 index 000000000..b6ea665a6 --- /dev/null +++ b/swarm/storage/feed/feed.go @@ -0,0 +1,125 @@ +// 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 ( + "hash" + "unsafe" + + "github.com/ethereum/go-ethereum/common" + "github.com/ethereum/go-ethereum/common/hexutil" + "github.com/ethereum/go-ethereum/swarm/storage" +) + +// Feed represents a particular user's stream of updates on a topic +type Feed struct { + Topic Topic `json:"topic"` + User common.Address `json:"user"` +} + +// Feed layout: +// TopicLength bytes +// userAddr common.AddressLength bytes +const feedLength = TopicLength + common.AddressLength + +// mapKey calculates a unique id for this feed. Used by the cache map in `Handler` +func (f *Feed) mapKey() uint64 { + serializedData := make([]byte, feedLength) + f.binaryPut(serializedData) + hasher := hashPool.Get().(hash.Hash) + defer hashPool.Put(hasher) + hasher.Reset() + hasher.Write(serializedData) + hash := hasher.Sum(nil) + return *(*uint64)(unsafe.Pointer(&hash[0])) +} + +// binaryPut serializes this feed instance into the provided slice +func (f *Feed) binaryPut(serializedData []byte) error { + if len(serializedData) != feedLength { + return NewErrorf(ErrInvalidValue, "Incorrect slice size to serialize feed. Expected %d, got %d", feedLength, len(serializedData)) + } + var cursor int + copy(serializedData[cursor:cursor+TopicLength], f.Topic[:TopicLength]) + cursor += TopicLength + + copy(serializedData[cursor:cursor+common.AddressLength], f.User[:]) + cursor += common.AddressLength + + return nil +} + +// binaryLength returns the expected size of this structure when serialized +func (f *Feed) binaryLength() int { + return feedLength +} + +// binaryGet restores the current instance from the information contained in the passed slice +func (f *Feed) binaryGet(serializedData []byte) error { + if len(serializedData) != feedLength { + return NewErrorf(ErrInvalidValue, "Incorrect slice size to read feed. Expected %d, got %d", feedLength, len(serializedData)) + } + + var cursor int + copy(f.Topic[:], serializedData[cursor:cursor+TopicLength]) + cursor += TopicLength + + copy(f.User[:], serializedData[cursor:cursor+common.AddressLength]) + cursor += common.AddressLength + + return nil +} + +// Hex serializes the feed to a hex string +func (f *Feed) Hex() string { + serializedData := make([]byte, feedLength) + f.binaryPut(serializedData) + return hexutil.Encode(serializedData) +} + +// FromValues deserializes this instance from a string key-value store +// useful to parse query strings +func (f *Feed) FromValues(values Values) (err error) { + topic := values.Get("topic") + if topic != "" { + if err := f.Topic.FromHex(values.Get("topic")); err != nil { + return err + } + } else { // see if the user set name and relatedcontent + name := values.Get("name") + relatedContent, _ := hexutil.Decode(values.Get("relatedcontent")) + if len(relatedContent) > 0 { + if len(relatedContent) < storage.AddressLength { + return NewErrorf(ErrInvalidValue, "relatedcontent field must be a hex-encoded byte array exactly %d bytes long", storage.AddressLength) + } + relatedContent = relatedContent[:storage.AddressLength] + } + f.Topic, err = NewTopic(name, relatedContent) + if err != nil { + return err + } + } + f.User = common.HexToAddress(values.Get("user")) + return nil +} + +// AppendValues serializes this structure into the provided string key-value store +// useful to build query strings +func (f *Feed) AppendValues(values Values) { + values.Set("topic", f.Topic.Hex()) + values.Set("user", f.User.Hex()) +} |