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// Copyright 2014 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/>.
// Contains the message filter for fine grained subscriptions.
package whisper
import (
"crypto/ecdsa"
"github.com/ethereum/go-ethereum/event/filter"
)
// Filter is used to subscribe to specific types of whisper messages.
type Filter struct {
To *ecdsa.PublicKey // Recipient of the message
From *ecdsa.PublicKey // Sender of the message
Topics [][]Topic // Topics to filter messages with
Fn func(msg *Message) // Handler in case of a match
}
// NewFilterTopics creates a 2D topic array used by whisper.Filter from binary
// data elements.
func NewFilterTopics(data ...[][]byte) [][]Topic {
filter := make([][]Topic, len(data))
for i, condition := range data {
// Handle the special case of condition == [[]byte{}]
if len(condition) == 1 && len(condition[0]) == 0 {
filter[i] = []Topic{}
continue
}
// Otherwise flatten normally
filter[i] = NewTopics(condition...)
}
return filter
}
// NewFilterTopicsFlat creates a 2D topic array used by whisper.Filter from flat
// binary data elements.
func NewFilterTopicsFlat(data ...[]byte) [][]Topic {
filter := make([][]Topic, len(data))
for i, element := range data {
// Only add non-wildcard topics
filter[i] = make([]Topic, 0, 1)
if len(element) > 0 {
filter[i] = append(filter[i], NewTopic(element))
}
}
return filter
}
// NewFilterTopicsFromStrings creates a 2D topic array used by whisper.Filter
// from textual data elements.
func NewFilterTopicsFromStrings(data ...[]string) [][]Topic {
filter := make([][]Topic, len(data))
for i, condition := range data {
// Handle the special case of condition == [""]
if len(condition) == 1 && condition[0] == "" {
filter[i] = []Topic{}
continue
}
// Otherwise flatten normally
filter[i] = NewTopicsFromStrings(condition...)
}
return filter
}
// NewFilterTopicsFromStringsFlat creates a 2D topic array used by whisper.Filter from flat
// binary data elements.
func NewFilterTopicsFromStringsFlat(data ...string) [][]Topic {
filter := make([][]Topic, len(data))
for i, element := range data {
// Only add non-wildcard topics
filter[i] = make([]Topic, 0, 1)
if element != "" {
filter[i] = append(filter[i], NewTopicFromString(element))
}
}
return filter
}
// filterer is the internal, fully initialized filter ready to match inbound
// messages to a variety of criteria.
type filterer struct {
to string // Recipient of the message
from string // Sender of the message
matcher *topicMatcher // Topics to filter messages with
fn func(data interface{}) // Handler in case of a match
}
// Compare checks if the specified filter matches the current one.
func (self filterer) Compare(f filter.Filter) bool {
filter := f.(filterer)
// Check the message sender and recipient
if len(self.to) > 0 && self.to != filter.to {
return false
}
if len(self.from) > 0 && self.from != filter.from {
return false
}
// Check the topic filtering
topics := make([]Topic, len(filter.matcher.conditions))
for i, group := range filter.matcher.conditions {
// Message should contain a single topic entry, extract
for topics[i], _ = range group {
break
}
}
if !self.matcher.Matches(topics) {
return false
}
return true
}
// Trigger is called when a filter successfully matches an inbound message.
func (self filterer) Trigger(data interface{}) {
self.fn(data)
}
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