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49 lines
1.2 KiB
Go
49 lines
1.2 KiB
Go
// Copyright 2017, Google
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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 b2
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import (
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"io"
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"sync"
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)
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type readerAt struct {
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rs io.ReadSeeker
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mu sync.Mutex
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}
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func (r *readerAt) ReadAt(p []byte, off int64) (int, error) {
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r.mu.Lock()
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defer r.mu.Unlock()
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// ReadAt is supposed to preserve the offset.
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cur, err := r.rs.Seek(0, io.SeekCurrent)
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if err != nil {
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return 0, err
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}
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defer func() { r.rs.Seek(cur, io.SeekStart) }()
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if _, err := r.rs.Seek(off, io.SeekStart); err != nil {
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return 0, err
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}
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return io.ReadFull(r.rs, p)
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}
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// wraps a ReadSeeker in a mutex to provite a ReaderAt how is this not in the
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// io package?
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func enReaderAt(rs io.ReadSeeker) io.ReaderAt {
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return &readerAt{rs: rs}
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}
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