55 строки
1.6 KiB
Go
55 строки
1.6 KiB
Go
// Copyright (c) Microsoft. All rights reserved.
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// Licensed under the MIT license. See LICENSE file in the project root for details.
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package main
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import (
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"errors"
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"github.com/colinmarc/hdfs"
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)
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// Allows to open HDFS file as a seekable/flushable/truncatable write-only stream
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// Concurrency: not thread safe: at most on request at a time
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type HdfsWriter interface {
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Seek(pos int64) error // Seeks to a given position
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Write(buffer []byte) (int, error) // Writes chunk of data
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Flush() error // Flushes all the data
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Close() error // Closes the stream
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Truncate() error // Truncate the HDFS file at a given position
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}
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type hdfsWriterImpl struct {
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BackendWriter *hdfs.FileWriter
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}
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var _ HdfsWriter = (*hdfsWriterImpl)(nil) // ensure hdfsWriterImpl implements HdfsWriter
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// Creates new instance of HdfsWriter
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func NewHdfsWriter(backendWriter *hdfs.FileWriter) HdfsWriter {
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return &hdfsWriterImpl{BackendWriter: backendWriter}
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}
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// Seeks to a given position
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func (this *hdfsWriterImpl) Seek(pos int64) error {
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return errors.New("Seek is not implemented")
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}
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// Writes chunk of data
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func (this *hdfsWriterImpl) Write(buffer []byte) (int, error) {
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return this.BackendWriter.Write(buffer)
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}
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// Flushes all the data
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func (this *hdfsWriterImpl) Flush() error {
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return errors.New("Flush is not implemented")
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}
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// Closes the stream
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func (this *hdfsWriterImpl) Truncate() error {
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return errors.New("Truncate is not implemented")
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}
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// Truncate the HDFS file at a given position
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func (this *hdfsWriterImpl) Close() error {
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return this.BackendWriter.Close()
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}
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