105 lines
2.9 KiB
Go
105 lines
2.9 KiB
Go
// Copyright 2019 The Waku Library Authors.
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//
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// The Waku library is free software: you can redistribute it and/or modify
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// it under the terms of the GNU Lesser General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// The Waku library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty off
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU Lesser General Public License for more details.
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//
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// You should have received a copy of the GNU Lesser General Public License
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// along with the Waku library. If not, see <http://www.gnu.org/licenses/>.
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//
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// This software uses the go-ethereum library, which is licensed
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// under the GNU Lesser General Public Library, version 3 or any later.
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package common
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import (
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"errors"
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"strings"
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"github.com/ethereum/go-ethereum/common/hexutil"
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)
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// TopicType represents a cryptographically secure, probabilistic partial
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// classifications of a message, determined as the first (leftmost) 4 bytes of the
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// SHA3 hash of some arbitrary data given by the original author of the message.
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type TopicType [TopicLength]byte
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type TopicSet map[TopicType]struct{}
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func NewTopicSet(topics []TopicType) TopicSet {
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s := make(TopicSet, len(topics))
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for _, t := range topics {
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s[t] = struct{}{}
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}
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return s
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}
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func NewTopicSetFromBytes(byteArrays [][]byte) TopicSet {
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topics := make([]TopicType, len(byteArrays))
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for i, byteArr := range byteArrays {
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topics[i] = BytesToTopic(byteArr)
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}
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return NewTopicSet(topics)
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}
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// BytesToTopic converts from the byte array representation of a topic
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// into the TopicType type.
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func BytesToTopic(b []byte) (t TopicType) {
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sz := TopicLength
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if x := len(b); x < TopicLength {
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sz = x
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}
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for i := 0; i < sz; i++ {
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t[i] = b[i]
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}
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return t
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}
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func StringToTopic(s string) (t TopicType) {
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str, _ := hexutil.Decode(s)
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return BytesToTopic(str)
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}
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// String converts a topic byte array to a string representation.
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func (t *TopicType) String() string {
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return hexutil.Encode(t[:])
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}
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// MarshalText returns the hex representation of t.
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func (t TopicType) MarshalText() ([]byte, error) {
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return hexutil.Bytes(t[:]).MarshalText()
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}
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// UnmarshalText parses a hex representation to a topic.
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func (t *TopicType) UnmarshalText(input []byte) error {
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return hexutil.UnmarshalFixedText("Topic", input, t[:])
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}
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// Converts a topic to its 23/WAKU2-TOPICS representation
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func (t TopicType) ContentTopic() string {
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enc := hexutil.Encode(t[:])
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return "/waku/1/" + enc + "/rfc26"
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}
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func ExtractTopicFromContentTopic(s string) (TopicType, error) {
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p := strings.Split(s, "/")
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if len(p) != 5 || p[1] != "waku" || p[2] != "1" || p[4] != "rfc26" {
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return TopicType{}, errors.New("invalid content topic format")
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}
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str, err := hexutil.Decode(p[3])
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if err != nil {
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return TopicType{}, err
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}
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result := BytesToTopic(str)
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return result, nil
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}
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