87 lines
2.0 KiB
Go
87 lines
2.0 KiB
Go
// Copyright (C) 2019 Storj Labs, Inc.
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// See LICENSE for copying information
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package sync2
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import (
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"io"
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"os"
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"sync/atomic"
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"github.com/zeebo/errs"
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)
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// ReadAtWriteAtCloser implements all io.ReaderAt, io.WriterAt and io.Closer
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type ReadAtWriteAtCloser interface {
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io.ReaderAt
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io.WriterAt
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io.Closer
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}
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// PipeWriter allows closing the writer with an error
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type PipeWriter interface {
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io.WriteCloser
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CloseWithError(reason error) error
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}
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// PipeReader allows closing the reader with an error
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type PipeReader interface {
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io.ReadCloser
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CloseWithError(reason error) error
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}
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// memory implements ReadAtWriteAtCloser on a memory buffer
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type memory []byte
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// Size returns size of memory buffer
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func (memory memory) Size() int { return len(memory) }
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// ReadAt implements io.ReaderAt methods
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func (memory memory) ReadAt(data []byte, at int64) (amount int, err error) {
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if at > int64(len(memory)) {
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return 0, io.ErrClosedPipe
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}
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amount = copy(data, memory[at:])
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return amount, nil
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}
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// WriteAt implements io.WriterAt methods
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func (memory memory) WriteAt(data []byte, at int64) (amount int, err error) {
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if at > int64(len(memory)) {
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return 0, io.ErrClosedPipe
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}
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amount = copy(memory[at:], data)
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return amount, nil
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}
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// Close implements io.Closer implementation
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func (memory memory) Close() error { return nil }
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// offsetFile implements ReadAt, WriteAt offset to the file with reference counting
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type offsetFile struct {
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file *os.File
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offset int64
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open *int64 // number of handles open
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}
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// ReadAt implements io.ReaderAt methods
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func (file offsetFile) ReadAt(data []byte, at int64) (amount int, err error) {
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return file.file.ReadAt(data, file.offset+at)
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}
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// WriteAt implements io.WriterAt methods
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func (file offsetFile) WriteAt(data []byte, at int64) (amount int, err error) {
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return file.file.WriteAt(data, file.offset+at)
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}
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// Close implements io.Closer methods
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func (file offsetFile) Close() error {
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if atomic.AddInt64(file.open, -1) == 0 {
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return errs.Combine(
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file.file.Close(),
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os.Remove(file.file.Name()),
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)
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}
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return nil
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}
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