aboutsummaryrefslogtreecommitdiffstats
path: root/bug/operation.go
blob: 2298a0082bc55fdfa7c38fd02bc3acae97cb36b2 (plain) (blame)
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
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
package bug

import (
	"crypto/sha256"
	"encoding/json"
	"fmt"
	"time"

	"github.com/MichaelMure/git-bug/identity"

	"github.com/MichaelMure/git-bug/util/git"
	"github.com/pkg/errors"
)

// OperationType is an operation type identifier
type OperationType int

const (
	_ OperationType = iota
	CreateOp
	SetTitleOp
	AddCommentOp
	SetStatusOp
	LabelChangeOp
	EditCommentOp
	NoOpOp
	SetMetadataOp
)

const unsetIDMarker = "unset"

// Operation define the interface to fulfill for an edit operation of a Bug
type Operation interface {
	// base return the OpBase of the Operation, for package internal use
	base() *OpBase
	// ID return the identifier of the operation, to be used for back references
	ID() string
	// Time return the time when the operation was added
	Time() time.Time
	// GetUnixTime return the unix timestamp when the operation was added
	GetUnixTime() int64
	// GetFiles return the files needed by this operation
	GetFiles() []git.Hash
	// Apply the operation to a Snapshot to create the final state
	Apply(snapshot *Snapshot)
	// Validate check if the operation is valid (ex: a title is a single line)
	Validate() error
	// SetMetadata store arbitrary metadata about the operation
	SetMetadata(key string, value string)
	// GetMetadata retrieve arbitrary metadata about the operation
	GetMetadata(key string) (string, bool)
	// AllMetadata return all metadata for this operation
	AllMetadata() map[string]string
	// GetAuthor return the author identity
	GetAuthor() identity.Interface
}

func hashRaw(data []byte) string {
	hasher := sha256.New()
	// Write can't fail
	_, _ = hasher.Write(data)
	return fmt.Sprintf("%x", hasher.Sum(nil))
}

func idOperation(op Operation) string {
	base := op.base()

	if base.id == "" {
		// something went really wrong
		panic("op's id not set")
	}
	if base.id == "unset" {
		// This means we are trying to get the op's ID *before* it has been stored, for instance when
		// adding multiple ops in one go in an OperationPack.
		// As the ID is computed based on the actual bytes written on the disk, we are going to predict
		// those and then get the ID. This is safe as it will be the exact same code writing on disk later.

		data, err := json.Marshal(op)
		if err != nil {
			panic(err)
		}

		base.id = hashRaw(data)
	}
	return base.id
}

func IDIsValid(id string) bool {
	// IDs have the same format as a git hash
	if len(id) != 40 && len(id) != 64 {
		return false
	}
	for _, r := range id {
		if (r < 'a' || r > 'z') && (r < '0' || r > '9') {
			return false
		}
	}
	return true
}

// OpBase implement the common code for all operations
type OpBase struct {
	OperationType OperationType
	Author        identity.Interface
	UnixTime      int64
	Metadata      map[string]string
	// Not serialized. Store the op's id in memory.
	id string
	// Not serialized. Store the extra metadata in memory,
	// compiled from SetMetadataOperation.
	extraMetadata map[string]string
}

// newOpBase is the constructor for an OpBase
func newOpBase(opType OperationType, author identity.Interface, unixTime int64) OpBase {
	return OpBase{
		OperationType: opType,
		Author:        author,
		UnixTime:      unixTime,
		id:            unsetIDMarker,
	}
}

func (op OpBase) MarshalJSON() ([]byte, error) {
	return json.Marshal(struct {
		OperationType OperationType      `json:"type"`
		Author        identity.Interface `json:"author"`
		UnixTime      int64              `json:"timestamp"`
		Metadata      map[string]string  `json:"metadata,omitempty"`
	}{
		OperationType: op.OperationType,
		Author:        op.Author,
		UnixTime:      op.UnixTime,
		Metadata:      op.Metadata,
	})
}

func (op *OpBase) UnmarshalJSON(data []byte) error {
	// Compute the ID when loading the op from disk.
	op.id = hashRaw(data)

	aux := struct {
		OperationType OperationType     `json:"type"`
		Author        json.RawMessage   `json:"author"`
		UnixTime      int64             `json:"timestamp"`
		Metadata      map[string]string `json:"metadata,omitempty"`
	}{}

	if err := json.Unmarshal(data, &aux); err != nil {
		return err
	}

	// delegate the decoding of the identity
	author, err := identity.UnmarshalJSON(aux.Author)
	if err != nil {
		return err
	}

	op.OperationType = aux.OperationType
	op.Author = author
	op.UnixTime = aux.UnixTime
	op.Metadata = aux.Metadata

	return nil
}

// Time return the time when the operation was added
func (op *OpBase) Time() time.Time {
	return time.Unix(op.UnixTime, 0)
}

// GetUnixTime return the unix timestamp when the operation was added
func (op *OpBase) GetUnixTime() int64 {
	return op.UnixTime
}

// GetFiles return the files needed by this operation
func (op *OpBase) GetFiles() []git.Hash {
	return nil
}

// Validate check the OpBase for errors
func opBaseValidate(op Operation, opType OperationType) error {
	if op.base().OperationType != opType {
		return fmt.Errorf("incorrect operation type (expected: %v, actual: %v)", opType, op.base().OperationType)
	}

	if op.GetUnixTime() == 0 {
		return fmt.Errorf("time not set")
	}

	if op.base().Author == nil {
		return fmt.Errorf("author not set")
	}

	if err := op.base().Author.Validate(); err != nil {
		return errors.Wrap(err, "author")
	}

	for _, hash := range op.GetFiles() {
		if !hash.IsValid() {
			return fmt.Errorf("file with invalid hash %v", hash)
		}
	}

	return nil
}

// SetMetadata store arbitrary metadata about the operation
func (op *OpBase) SetMetadata(key string, value string) {
	if op.Metadata == nil {
		op.Metadata = make(map[string]string)
	}

	op.Metadata[key] = value
	op.id = unsetIDMarker
}

// GetMetadata retrieve arbitrary metadata about the operation
func (op *OpBase) GetMetadata(key string) (string, bool) {
	val, ok := op.Metadata[key]

	if ok {
		return val, true
	}

	// extraMetadata can't replace the original operations value if any
	val, ok = op.extraMetadata[key]

	return val, ok
}

// AllMetadata return all metadata for this operation
func (op *OpBase) AllMetadata() map[string]string {
	result := make(map[string]string)

	for key, val := range op.extraMetadata {
		result[key] = val
	}

	// Original metadata take precedence
	for key, val := range op.Metadata {
		result[key] = val
	}

	return result
}

// GetAuthor return author identity
func (op *OpBase) GetAuthor() identity.Interface {
	return op.Author
}