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/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/
package thrift
import (
"net"
"sync/atomic"
)
// socketConn is a wrapped net.Conn that tries to do connectivity check.
type socketConn struct {
net.Conn
buffer [1]byte
closed int32
}
var _ net.Conn = (*socketConn)(nil)
// createSocketConnFromReturn is a language sugar to help create socketConn from
// return values of functions like net.Dial, tls.Dial, net.Listener.Accept, etc.
func createSocketConnFromReturn(conn net.Conn, err error) (*socketConn, error) {
if err != nil {
return nil, err
}
return &socketConn{
Conn: conn,
}, nil
}
// wrapSocketConn wraps an existing net.Conn into *socketConn.
func wrapSocketConn(conn net.Conn) *socketConn {
// In case conn is already wrapped,
// return it as-is and avoid double wrapping.
if sc, ok := conn.(*socketConn); ok {
return sc
}
return &socketConn{
Conn: conn,
}
}
// isValid checks whether there's a valid connection.
//
// It's nil safe, and returns false if sc itself is nil, or if the underlying
// connection is nil.
//
// It's the same as the previous implementation of TSocket.IsOpen and
// TSSLSocket.IsOpen before we added connectivity check.
func (sc *socketConn) isValid() bool {
return sc != nil && sc.Conn != nil && atomic.LoadInt32(&sc.closed) == 0
}
// IsOpen checks whether the connection is open.
//
// It's nil safe, and returns false if sc itself is nil, or if the underlying
// connection is nil.
//
// Otherwise, it tries to do a connectivity check and returns the result.
//
// It also has the side effect of resetting the previously set read deadline on
// the socket. As a result, it shouldn't be called between setting read deadline
// and doing actual read.
func (sc *socketConn) IsOpen() bool {
if !sc.isValid() {
return false
}
return sc.checkConn() == nil
}
// Read implements io.Reader.
//
// On Windows, it behaves the same as the underlying net.Conn.Read.
//
// On non-Windows, it treats len(p) == 0 as a connectivity check instead of
// readability check, which means instead of blocking until there's something to
// read (readability check), or always return (0, nil) (the default behavior of
// go's stdlib implementation on non-Windows), it never blocks, and will return
// an error if the connection is lost.
func (sc *socketConn) Read(p []byte) (n int, err error) {
if len(p) == 0 {
return 0, sc.read0()
}
return sc.Conn.Read(p)
}
func (sc *socketConn) Close() error {
if !sc.isValid() {
// Already closed
return net.ErrClosed
}
atomic.StoreInt32(&sc.closed, 1)
return sc.Conn.Close()
}
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