1. 1
2. 2
3. 3
4. 4
5. 5
6. 6
7. 7
8. 8
9. 9
10. 10
11. 11
12. 12
13. 13
14. 14
15. 15
16. 16
17. 17
18. 18
19. 19
20. 20
21. 21
22. 22
23. 23
24. 24
25. 25
26. 26
27. 27
28. 28
29. 29
30. 30
31. 31
32. 32
33. 33
34. 34
35. 35
36. 36
37. 37
38. 38
39. 39
40. 40
41. 41
42. 42
43. 43
44. 44
45. 45
46. 46
47. 47
48. 48
49. 49
50. 50
51. 51
52. 52
53. 53
54. 54
55. 55
56. 56
57. 57
58. 58
59. 59
60. 60
61. 61
62. 62
63. 63
64. 64
65. 65
66. 66
67. 67
68. 68
69. 69
70. 70
71. 71
72. 72
73. 73
74. 74
75. 75
76. 76
77. 77
78. 78
79. 79
80. 80
81. 81
82. 82
83. 83
84. 84
85. 85
86. 86
87. 87
88. 88
89. 89
90. 90
91. 91
92. 92
93. 93
94. 94
95. 95
96. 96
97. 97
98. 98
99. 99
100. 100
101. 101
102. 102
103. 103
104. 104
105. 105
106. 106
107. 107
108. 108
109. 109
110. 110
111. 111
112. 112
113. 113
114. 114
115. 115
116. 116
117. 117
118. 118
119. 119
120. 120
121. 121
122. 122
123. 123
124. 124
125. 125
126. 126
127. 127
128. 128
129. 129
130. 130
131. 131
132. 132
133. 133
134. 134
135. 135
136. 136
137. 137
138. 138
139. 139
140. 140
141. 141
142. 142
143. 143
144. 144
145. 145
146. 146
147. 147
148. 148
149. 149
150. 150
151. 151
152. 152
153. 153
154. 154
155. 155
156. 156
157. 157
158. 158
159. 159
160. 160
161. 161
162. 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 models.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(),
	}
}