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