mirror of https://github.com/poanetwork/quorum.git
81 lines
2.0 KiB
Go
81 lines
2.0 KiB
Go
// Copyright 2013 The etcd Authors
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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// Package transport provides network utility functions, complementing the more
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// common ones in the net package.
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package transport
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import (
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"errors"
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"net"
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"sync"
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"time"
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)
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var (
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ErrNotTCP = errors.New("only tcp connections have keepalive")
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)
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// LimitListener returns a Listener that accepts at most n simultaneous
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// connections from the provided Listener.
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func LimitListener(l net.Listener, n int) net.Listener {
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return &limitListener{l, make(chan struct{}, n)}
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}
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type limitListener struct {
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net.Listener
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sem chan struct{}
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}
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func (l *limitListener) acquire() { l.sem <- struct{}{} }
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func (l *limitListener) release() { <-l.sem }
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func (l *limitListener) Accept() (net.Conn, error) {
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l.acquire()
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c, err := l.Listener.Accept()
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if err != nil {
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l.release()
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return nil, err
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}
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return &limitListenerConn{Conn: c, release: l.release}, nil
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}
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type limitListenerConn struct {
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net.Conn
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releaseOnce sync.Once
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release func()
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}
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func (l *limitListenerConn) Close() error {
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err := l.Conn.Close()
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l.releaseOnce.Do(l.release)
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return err
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}
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func (l *limitListenerConn) SetKeepAlive(doKeepAlive bool) error {
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tcpc, ok := l.Conn.(*net.TCPConn)
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if !ok {
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return ErrNotTCP
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}
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return tcpc.SetKeepAlive(doKeepAlive)
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}
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func (l *limitListenerConn) SetKeepAlivePeriod(d time.Duration) error {
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tcpc, ok := l.Conn.(*net.TCPConn)
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if !ok {
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return ErrNotTCP
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}
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return tcpc.SetKeepAlivePeriod(d)
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}
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