mirror of
https://github.com/minio/minio.git
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102 lines
2.6 KiB
Go
102 lines
2.6 KiB
Go
/*
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* Minio Cloud Storage, (C) 2016 Minio, Inc.
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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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*/
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package main
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import (
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"crypto/sha512"
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"hash"
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"io"
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"github.com/klauspost/reedsolomon"
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)
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// newHashWriters - inititialize a slice of hashes for the disk count.
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func newHashWriters(diskCount int) []hash.Hash {
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hashWriters := make([]hash.Hash, diskCount)
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for index := range hashWriters {
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hashWriters[index] = newHash("sha512")
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}
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return hashWriters
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}
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// newHash - gives you a newly allocated hash depending on the input algorithm.
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func newHash(algo string) hash.Hash {
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switch algo {
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case "sha512":
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return sha512.New()
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// Add new hashes here.
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default:
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return sha512.New()
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}
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}
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func hashSum(disk StorageAPI, volume, path string, writer hash.Hash) ([]byte, error) {
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startOffset := int64(0)
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// Read until io.EOF.
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for {
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buf := make([]byte, blockSizeV1)
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n, err := disk.ReadFile(volume, path, startOffset, buf)
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if err == io.EOF {
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break
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}
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if err != nil {
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return nil, err
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}
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writer.Write(buf[:n])
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startOffset += n
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}
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return writer.Sum(nil), nil
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}
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// getDataBlocks - fetches the data block only part of the input encoded blocks.
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func getDataBlocks(enBlocks [][]byte, dataBlocks int, curBlockSize int) (data []byte, err error) {
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if len(enBlocks) < dataBlocks {
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return nil, reedsolomon.ErrTooFewShards
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}
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size := 0
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blocks := enBlocks[:dataBlocks]
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for _, block := range blocks {
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size += len(block)
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}
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if size < curBlockSize {
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return nil, reedsolomon.ErrShortData
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}
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write := curBlockSize
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for _, block := range blocks {
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if write < len(block) {
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data = append(data, block[:write]...)
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return data, nil
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}
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data = append(data, block...)
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write -= len(block)
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}
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return data, nil
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}
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// getBlockInfo - find start/end block and bytes to skip for given offset, length and block size.
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func getBlockInfo(offset, length, blockSize int64) (startBlock, bytesToSkip, endBlock int64) {
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// Calculate start block for given offset and how many bytes to skip to get the offset.
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startBlock = offset / blockSize
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bytesToSkip = offset % blockSize
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// Calculate end block for given size to read
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endBlock = (offset + length) / blockSize
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return
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}
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