52 lines
992 B
Go
52 lines
992 B
Go
package httpd
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import (
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"net"
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"sync"
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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 and will drop extra connections.
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func LimitListener(l net.Listener, n int) net.Listener {
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return &limitListener{Listener: l, sem: make(chan struct{}, n)}
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}
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// limitListener is a listener that limits the number of active connections
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// at any given time.
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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) release() {
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<-l.sem
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}
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func (l *limitListener) Accept() (net.Conn, error) {
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for {
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c, err := l.Listener.Accept()
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if err != nil {
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return nil, err
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}
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select {
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case l.sem <- struct{}{}:
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return &limitListenerConn{Conn: c, release: l.release}, nil
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default:
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c.Close()
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}
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}
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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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