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// Copyright 2018 The gVisor Authors.
//
// Licensed 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 vecnet provides access to recvmsg syscalls on net.Conns.
package vecnet
import (
"io"
"net"
"syscall"
)
// Buffers points to zero or more buffers to read into.
//
// On connections that support it, ReadFrom is optimized into the batch read
// operation recvmsg.
type Buffers net.Buffers
// ReadFrom reads into the pre-allocated bufs. Returns bytes read.
//
// ReadFrom keeps reading until all bufs are filled or EOF is received.
//
// The pre-allocatted space used by ReadFrom is based upon slice lengths.
func (bufs Buffers) ReadFrom(r io.Reader) (int64, error) {
if conn, ok := r.(syscall.Conn); ok && readFromBuffers != nil {
return readFromBuffers(bufs, conn)
}
var total int64
for _, buf := range bufs {
for filled := 0; filled < len(buf); {
n, err := r.Read(buf[filled:])
total += int64(n)
filled += n
if (n == 0 && err == nil) || err == io.EOF {
return total, io.EOF
} else if err != nil {
return total, err
}
}
}
return total, nil
}
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