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
--- /dev/null
+++ 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())
+}