aboutsummaryrefslogtreecommitdiffstats
path: root/modules/lfs/content_store.go
blob: c794a1feccc6fb985f2f167b4f16a448fd21b3f1 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
// Copyright 2020 The Gitea Authors. All rights reserved.
// Use of this source code is governed by a MIT-style
// license that can be found in the LICENSE file.

package lfs

import (
	"crypto/sha256"
	"encoding/hex"
	"errors"
	"fmt"
	"hash"
	"io"
	"os"

	"code.gitea.io/gitea/modules/log"
	"code.gitea.io/gitea/modules/storage"
)

var (
	// ErrHashMismatch occurs if the content has does not match OID
	ErrHashMismatch = errors.New("Content hash does not match OID")
	// ErrSizeMismatch occurs if the content size does not match
	ErrSizeMismatch = errors.New("Content size does not match")
)

// ErrRangeNotSatisfiable represents an error which request range is not satisfiable.
type ErrRangeNotSatisfiable struct {
	FromByte int64
}

// IsErrRangeNotSatisfiable returns true if the error is an ErrRangeNotSatisfiable
func IsErrRangeNotSatisfiable(err error) bool {
	_, ok := err.(ErrRangeNotSatisfiable)
	return ok
}

func (err ErrRangeNotSatisfiable) Error() string {
	return fmt.Sprintf("Requested range %d is not satisfiable", err.FromByte)
}

// ContentStore provides a simple file system based storage.
type ContentStore struct {
	storage.ObjectStorage
}

// NewContentStore creates the default ContentStore
func NewContentStore() *ContentStore {
	contentStore := &ContentStore{ObjectStorage: storage.LFS}
	return contentStore
}

// Get takes a Meta object and retrieves the content from the store, returning
// it as an io.ReadSeekCloser.
func (s *ContentStore) Get(pointer Pointer) (storage.Object, error) {
	f, err := s.Open(pointer.RelativePath())
	if err != nil {
		log.Error("Whilst trying to read LFS OID[%s]: Unable to open Error: %v", pointer.Oid, err)
		return nil, err
	}
	return f, err
}

// Put takes a Meta object and an io.Reader and writes the content to the store.
func (s *ContentStore) Put(pointer Pointer, r io.Reader) error {
	p := pointer.RelativePath()

	// Wrap the provided reader with an inline hashing and size checker
	wrappedRd := newHashingReader(pointer.Size, pointer.Oid, r)

	// now pass the wrapped reader to Save - if there is a size mismatch or hash mismatch then
	// the errors returned by the newHashingReader should percolate up to here
	written, err := s.Save(p, wrappedRd, pointer.Size)
	if err != nil {
		log.Error("Whilst putting LFS OID[%s]: Failed to copy to tmpPath: %s Error: %v", pointer.Oid, p, err)
		return err
	}

	// This shouldn't happen but it is sensible to test
	if written != pointer.Size {
		if err := s.Delete(p); err != nil {
			log.Error("Cleaning the LFS OID[%s] failed: %v", pointer.Oid, err)
		}
		return ErrSizeMismatch
	}

	return nil
}

// Exists returns true if the object exists in the content store.
func (s *ContentStore) Exists(pointer Pointer) (bool, error) {
	_, err := s.ObjectStorage.Stat(pointer.RelativePath())
	if err != nil {
		if os.IsNotExist(err) {
			return false, nil
		}
		return false, err
	}
	return true, nil
}

// Verify returns true if the object exists in the content store and size is correct.
func (s *ContentStore) Verify(pointer Pointer) (bool, error) {
	p := pointer.RelativePath()
	fi, err := s.ObjectStorage.Stat(p)
	if os.IsNotExist(err) || (err == nil && fi.Size() != pointer.Size) {
		return false, nil
	} else if err != nil {
		log.Error("Unable stat file: %s for LFS OID[%s] Error: %v", p, pointer.Oid, err)
		return false, err
	}

	return true, nil
}

// ReadMetaObject will read a git_model.LFSMetaObject and return a reader
func ReadMetaObject(pointer Pointer) (io.ReadCloser, error) {
	contentStore := NewContentStore()
	return contentStore.Get(pointer)
}

type hashingReader struct {
	internal     io.Reader
	currentSize  int64
	expectedSize int64
	hash         hash.Hash
	expectedHash string
}

func (r *hashingReader) Read(b []byte) (int, error) {
	n, err := r.internal.Read(b)

	if n > 0 {
		r.currentSize += int64(n)
		wn, werr := r.hash.Write(b[:n])
		if wn != n || werr != nil {
			return n, werr
		}
	}

	if err != nil && err == io.EOF {
		if r.currentSize != r.expectedSize {
			return n, ErrSizeMismatch
		}

		shaStr := hex.EncodeToString(r.hash.Sum(nil))
		if shaStr != r.expectedHash {
			return n, ErrHashMismatch
		}
	}

	return n, err
}

func newHashingReader(expectedSize int64, expectedHash string, reader io.Reader) *hashingReader {
	return &hashingReader{
		internal:     reader,
		expectedSize: expectedSize,
		expectedHash: expectedHash,
		hash:         sha256.New(),
	}
}