| // +build !windows |
| |
| /* |
| * 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 ( |
| "errors" |
| "io" |
| "syscall" |
| "time" |
| ) |
| |
| // We rely on this variable to be the zero time, |
| // but define it as global variable to avoid repetitive allocations. |
| // Please DO NOT mutate this variable in any way. |
| var zeroTime time.Time |
| |
| func (sc *socketConn) read0() error { |
| return sc.checkConn() |
| } |
| |
| func (sc *socketConn) checkConn() error { |
| syscallConn, ok := sc.Conn.(syscall.Conn) |
| if !ok { |
| // No way to check, return nil |
| return nil |
| } |
| |
| // The reading about to be done here is non-blocking so we don't really |
| // need a read deadline. We just need to clear the previously set read |
| // deadline, if any. |
| sc.Conn.SetReadDeadline(zeroTime) |
| |
| rc, err := syscallConn.SyscallConn() |
| if err != nil { |
| return err |
| } |
| |
| var n int |
| |
| if readErr := rc.Read(func(fd uintptr) bool { |
| n, _, err = syscall.Recvfrom(int(fd), sc.buffer[:], syscall.MSG_PEEK|syscall.MSG_DONTWAIT) |
| return true |
| }); readErr != nil { |
| return readErr |
| } |
| |
| if n > 0 { |
| // We got something, which means we are good |
| return nil |
| } |
| |
| if errors.Is(err, syscall.EAGAIN) || errors.Is(err, syscall.EWOULDBLOCK) { |
| // This means the connection is still open but we don't have |
| // anything to read right now. |
| return nil |
| } |
| |
| if err != nil { |
| return err |
| } |
| |
| // At this point, it means the other side already closed the connection. |
| return io.EOF |
| } |