127 lines
3.8 KiB
Go
127 lines
3.8 KiB
Go
// Copyright 2018 The gVisor 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 secio
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import (
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"bytes"
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"errors"
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"io"
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"io/ioutil"
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"math"
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"testing"
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)
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var errEndOfBuffer = errors.New("write beyond end of buffer")
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// buffer resembles bytes.Buffer, but implements io.ReaderAt and io.WriterAt.
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// Reads beyond the end of the buffer return io.EOF. Writes beyond the end of
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// the buffer return errEndOfBuffer.
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type buffer struct {
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Bytes []byte
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}
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// ReadAt implements io.ReaderAt.ReadAt.
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func (b *buffer) ReadAt(dst []byte, off int64) (int, error) {
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if off >= int64(len(b.Bytes)) {
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return 0, io.EOF
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}
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n := copy(dst, b.Bytes[off:])
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if n < len(dst) {
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return n, io.EOF
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}
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return n, nil
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}
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// WriteAt implements io.WriterAt.WriteAt.
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func (b *buffer) WriteAt(src []byte, off int64) (int, error) {
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if off >= int64(len(b.Bytes)) {
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return 0, errEndOfBuffer
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}
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n := copy(b.Bytes[off:], src)
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if n < len(src) {
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return n, errEndOfBuffer
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}
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return n, nil
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}
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func newBufferString(s string) *buffer {
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return &buffer{[]byte(s)}
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}
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func TestOffsetReader(t *testing.T) {
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buf := newBufferString("foobar")
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r := NewOffsetReader(buf, 3)
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dst, err := ioutil.ReadAll(r)
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if want := []byte("bar"); !bytes.Equal(dst, want) || err != nil {
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t.Errorf("ReadAll: got (%q, %v), wanted (%q, nil)", dst, err, want)
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}
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}
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func TestSectionReader(t *testing.T) {
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buf := newBufferString("foobarbaz")
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r := NewSectionReader(buf, 3, 3)
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dst, err := ioutil.ReadAll(r)
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if want, wantErr := []byte("bar"), ErrReachedLimit; !bytes.Equal(dst, want) || err != wantErr {
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t.Errorf("ReadAll: got (%q, %v), wanted (%q, %v)", dst, err, want, wantErr)
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}
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}
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func TestSectionReaderLimitOverflow(t *testing.T) {
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// SectionReader behaves like OffsetReader when limit overflows int64.
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buf := newBufferString("foobar")
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r := NewSectionReader(buf, 3, math.MaxInt64)
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dst, err := ioutil.ReadAll(r)
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if want := []byte("bar"); !bytes.Equal(dst, want) || err != nil {
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t.Errorf("ReadAll: got (%q, %v), wanted (%q, nil)", dst, err, want)
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}
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}
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func TestOffsetWriter(t *testing.T) {
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buf := newBufferString("ABCDEF")
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w := NewOffsetWriter(buf, 3)
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n, err := w.Write([]byte("foobar"))
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if wantN, wantErr := 3, errEndOfBuffer; n != wantN || err != wantErr {
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t.Errorf("WriteAt: got (%v, %v), wanted (%v, %v)", n, err, wantN, wantErr)
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}
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if got, want := buf.Bytes, []byte("ABCfoo"); !bytes.Equal(got, want) {
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t.Errorf("buf.Bytes: got %q, wanted %q", got, want)
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}
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}
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func TestSectionWriter(t *testing.T) {
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buf := newBufferString("ABCDEFGHI")
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w := NewSectionWriter(buf, 3, 3)
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n, err := w.Write([]byte("foobar"))
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if wantN, wantErr := 3, ErrReachedLimit; n != wantN || err != wantErr {
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t.Errorf("WriteAt: got (%v, %v), wanted (%v, %v)", n, err, wantN, wantErr)
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}
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if got, want := buf.Bytes, []byte("ABCfooGHI"); !bytes.Equal(got, want) {
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t.Errorf("buf.Bytes: got %q, wanted %q", got, want)
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}
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}
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func TestSectionWriterLimitOverflow(t *testing.T) {
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// SectionWriter behaves like OffsetWriter when limit overflows int64.
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buf := newBufferString("ABCDEF")
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w := NewSectionWriter(buf, 3, math.MaxInt64)
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n, err := w.Write([]byte("foobar"))
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if wantN, wantErr := 3, errEndOfBuffer; n != wantN || err != wantErr {
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t.Errorf("WriteAt: got (%v, %v), wanted (%v, %v)", n, err, wantN, wantErr)
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}
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if got, want := buf.Bytes, []byte("ABCfoo"); !bytes.Equal(got, want) {
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t.Errorf("buf.Bytes: got %q, wanted %q", got, want)
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}
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}
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