101 lines
3.0 KiB
Go
101 lines
3.0 KiB
Go
// Copyright 2015 The go-ethereum Authors
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// This file is part of the go-ethereum library.
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//
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// The go-ethereum 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 go-ethereum library 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 the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
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// Contains the external API side message filter for watching, pooling and polling
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// matched whisper messages, also serializing data access to avoid duplications.
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package xeth
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import (
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"sync"
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"time"
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"github.com/ethereum/go-ethereum/common"
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)
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// whisperFilter is the message cache matching a specific filter, accumulating
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// inbound messages until the are requested by the client.
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type whisperFilter struct {
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id int // Filter identifier for old message retrieval
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ref *Whisper // Whisper reference for old message retrieval
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cache []WhisperMessage // Cache of messages not yet polled
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skip map[common.Hash]struct{} // List of retrieved messages to avoid duplication
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update time.Time // Time of the last message query
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lock sync.RWMutex // Lock protecting the filter internals
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}
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// newWhisperFilter creates a new serialized, poll based whisper topic filter.
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func newWhisperFilter(id int, ref *Whisper) *whisperFilter {
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return &whisperFilter{
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id: id,
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ref: ref,
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update: time.Now(),
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skip: make(map[common.Hash]struct{}),
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}
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}
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// messages retrieves all the cached messages from the entire pool matching the
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// filter, resetting the filter's change buffer.
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func (w *whisperFilter) messages() []WhisperMessage {
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w.lock.Lock()
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defer w.lock.Unlock()
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w.cache = nil
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w.update = time.Now()
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w.skip = make(map[common.Hash]struct{})
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messages := w.ref.Messages(w.id)
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for _, message := range messages {
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w.skip[message.ref.Hash] = struct{}{}
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}
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return messages
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}
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// insert injects a new batch of messages into the filter cache.
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func (w *whisperFilter) insert(messages ...WhisperMessage) {
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w.lock.Lock()
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defer w.lock.Unlock()
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for _, message := range messages {
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if _, ok := w.skip[message.ref.Hash]; !ok {
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w.cache = append(w.cache, messages...)
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}
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}
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}
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// retrieve fetches all the cached messages from the filter.
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func (w *whisperFilter) retrieve() (messages []WhisperMessage) {
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w.lock.Lock()
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defer w.lock.Unlock()
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messages, w.cache = w.cache, nil
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w.update = time.Now()
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return
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}
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// activity returns the last time instance when client requests were executed on
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// the filter.
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func (w *whisperFilter) activity() time.Time {
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w.lock.RLock()
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defer w.lock.RUnlock()
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return w.update
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}
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