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-rw-r--r--swarm/storage/feeds/feed.go125
1 files changed, 125 insertions, 0 deletions
diff --git a/swarm/storage/feeds/feed.go b/swarm/storage/feeds/feed.go
new file mode 100644
index 000000000..8a807d506
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+++ b/swarm/storage/feeds/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 feeds
+
+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())
+}