133 lines
4.1 KiB
Go
133 lines
4.1 KiB
Go
// Copyright 2014 The go-ethereum Authors
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// This file is part of go-ethereum.
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//
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// go-ethereum 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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// go-ethereum is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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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 go-ethereum. If not, see <http://www.gnu.org/licenses/>.
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// Contains the message filter for fine grained subscriptions.
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package whisper
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import (
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"crypto/ecdsa"
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"github.com/ethereum/go-ethereum/event/filter"
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)
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// Filter is used to subscribe to specific types of whisper messages.
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type Filter struct {
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To *ecdsa.PublicKey // Recipient of the message
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From *ecdsa.PublicKey // Sender of the message
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Topics [][]Topic // Topics to filter messages with
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Fn func(msg *Message) // Handler in case of a match
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}
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// NewFilterTopics creates a 2D topic array used by whisper.Filter from binary
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// data elements.
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func NewFilterTopics(data ...[][]byte) [][]Topic {
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filter := make([][]Topic, len(data))
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for i, condition := range data {
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// Handle the special case of condition == [[]byte{}]
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if len(condition) == 1 && len(condition[0]) == 0 {
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filter[i] = []Topic{}
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continue
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}
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// Otherwise flatten normally
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filter[i] = NewTopics(condition...)
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}
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return filter
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}
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// NewFilterTopicsFlat creates a 2D topic array used by whisper.Filter from flat
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// binary data elements.
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func NewFilterTopicsFlat(data ...[]byte) [][]Topic {
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filter := make([][]Topic, len(data))
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for i, element := range data {
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// Only add non-wildcard topics
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filter[i] = make([]Topic, 0, 1)
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if len(element) > 0 {
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filter[i] = append(filter[i], NewTopic(element))
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}
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}
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return filter
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}
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// NewFilterTopicsFromStrings creates a 2D topic array used by whisper.Filter
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// from textual data elements.
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func NewFilterTopicsFromStrings(data ...[]string) [][]Topic {
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filter := make([][]Topic, len(data))
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for i, condition := range data {
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// Handle the special case of condition == [""]
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if len(condition) == 1 && condition[0] == "" {
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filter[i] = []Topic{}
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continue
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}
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// Otherwise flatten normally
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filter[i] = NewTopicsFromStrings(condition...)
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}
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return filter
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}
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// NewFilterTopicsFromStringsFlat creates a 2D topic array used by whisper.Filter from flat
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// binary data elements.
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func NewFilterTopicsFromStringsFlat(data ...string) [][]Topic {
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filter := make([][]Topic, len(data))
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for i, element := range data {
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// Only add non-wildcard topics
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filter[i] = make([]Topic, 0, 1)
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if element != "" {
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filter[i] = append(filter[i], NewTopicFromString(element))
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}
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}
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return filter
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}
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// filterer is the internal, fully initialized filter ready to match inbound
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// messages to a variety of criteria.
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type filterer struct {
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to string // Recipient of the message
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from string // Sender of the message
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matcher *topicMatcher // Topics to filter messages with
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fn func(data interface{}) // Handler in case of a match
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}
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// Compare checks if the specified filter matches the current one.
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func (self filterer) Compare(f filter.Filter) bool {
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filter := f.(filterer)
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// Check the message sender and recipient
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if len(self.to) > 0 && self.to != filter.to {
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return false
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}
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if len(self.from) > 0 && self.from != filter.from {
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return false
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}
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// Check the topic filtering
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topics := make([]Topic, len(filter.matcher.conditions))
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for i, group := range filter.matcher.conditions {
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// Message should contain a single topic entry, extract
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for topics[i], _ = range group {
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break
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}
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}
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if !self.matcher.Matches(topics) {
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return false
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}
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return true
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}
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// Trigger is called when a filter successfully matches an inbound message.
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func (self filterer) Trigger(data interface{}) {
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self.fn(data)
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}
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