aboutsummaryrefslogtreecommitdiffstats
path: root/plumbing/object/patch.go
blob: 068589eff8e1e59908458a2e9463aac90cd54bc1 (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
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
package object

import (
	"bytes"
	"context"
	"errors"
	"fmt"
	"io"
	"math"
	"strings"

	"gopkg.in/src-d/go-git.v4/plumbing"
	"gopkg.in/src-d/go-git.v4/plumbing/filemode"
	fdiff "gopkg.in/src-d/go-git.v4/plumbing/format/diff"
	"gopkg.in/src-d/go-git.v4/utils/diff"

	dmp "github.com/sergi/go-diff/diffmatchpatch"
)

var (
	ErrCanceled = errors.New("operation canceled")
)

func getPatch(message string, changes ...*Change) (*Patch, error) {
	ctx := context.Background()
	return getPatchContext(ctx, message, changes...)
}

func getPatchContext(ctx context.Context, message string, changes ...*Change) (*Patch, error) {
	var filePatches []fdiff.FilePatch
	for _, c := range changes {
		select {
		case <-ctx.Done():
			return nil, ErrCanceled
		default:
		}

		fp, err := filePatchWithContext(ctx, c)
		if err != nil {
			return nil, err
		}

		filePatches = append(filePatches, fp)
	}

	return &Patch{message, filePatches}, nil
}

func filePatchWithContext(ctx context.Context, c *Change) (fdiff.FilePatch, error) {
	from, to, err := c.Files()
	if err != nil {
		return nil, err
	}
	fromContent, fIsBinary, err := fileContent(from)
	if err != nil {
		return nil, err
	}

	toContent, tIsBinary, err := fileContent(to)
	if err != nil {
		return nil, err
	}

	if fIsBinary || tIsBinary {
		return &textFilePatch{from: c.From, to: c.To}, nil
	}

	diffs := diff.Do(fromContent, toContent)

	var chunks []fdiff.Chunk
	for _, d := range diffs {
		select {
		case <-ctx.Done():
			return nil, ErrCanceled
		default:
		}

		var op fdiff.Operation
		switch d.Type {
		case dmp.DiffEqual:
			op = fdiff.Equal
		case dmp.DiffDelete:
			op = fdiff.Delete
		case dmp.DiffInsert:
			op = fdiff.Add
		}

		chunks = append(chunks, &textChunk{d.Text, op})
	}

	return &textFilePatch{
		chunks: chunks,
		from:   c.From,
		to:     c.To,
	}, nil

}

func filePatch(c *Change) (fdiff.FilePatch, error) {
	return filePatchWithContext(context.Background(), c)
}

func fileContent(f *File) (content string, isBinary bool, err error) {
	if f == nil {
		return
	}

	isBinary, err = f.IsBinary()
	if err != nil || isBinary {
		return
	}

	content, err = f.Contents()

	return
}

// textPatch is an implementation of fdiff.Patch interface
type Patch struct {
	message     string
	filePatches []fdiff.FilePatch
}

func (t *Patch) FilePatches() []fdiff.FilePatch {
	return t.filePatches
}

func (t *Patch) Message() string {
	return t.message
}

func (p *Patch) Encode(w io.Writer) error {
	ue := fdiff.NewUnifiedEncoder(w, fdiff.DefaultContextLines)

	return ue.Encode(p)
}

func (p *Patch) Stats() FileStats {
	return getFileStatsFromFilePatches(p.FilePatches())
}

func (p *Patch) String() string {
	buf := bytes.NewBuffer(nil)
	err := p.Encode(buf)
	if err != nil {
		return fmt.Sprintf("malformed patch: %s", err.Error())
	}

	return buf.String()
}

// changeEntryWrapper is an implementation of fdiff.File interface
type changeEntryWrapper struct {
	ce ChangeEntry
}

func (f *changeEntryWrapper) Hash() plumbing.Hash {
	if !f.ce.TreeEntry.Mode.IsFile() {
		return plumbing.ZeroHash
	}

	return f.ce.TreeEntry.Hash
}

func (f *changeEntryWrapper) Mode() filemode.FileMode {
	return f.ce.TreeEntry.Mode
}
func (f *changeEntryWrapper) Path() string {
	if !f.ce.TreeEntry.Mode.IsFile() {
		return ""
	}

	return f.ce.Name
}

func (f *changeEntryWrapper) Empty() bool {
	return !f.ce.TreeEntry.Mode.IsFile()
}

// textFilePatch is an implementation of fdiff.FilePatch interface
type textFilePatch struct {
	chunks   []fdiff.Chunk
	from, to ChangeEntry
}

func (tf *textFilePatch) Files() (from fdiff.File, to fdiff.File) {
	f := &changeEntryWrapper{tf.from}
	t := &changeEntryWrapper{tf.to}

	if !f.Empty() {
		from = f
	}

	if !t.Empty() {
		to = t
	}

	return
}

func (t *textFilePatch) IsBinary() bool {
	return len(t.chunks) == 0
}

func (t *textFilePatch) Chunks() []fdiff.Chunk {
	return t.chunks
}

// textChunk is an implementation of fdiff.Chunk interface
type textChunk struct {
	content string
	op      fdiff.Operation
}

func (t *textChunk) Content() string {
	return t.content
}

func (t *textChunk) Type() fdiff.Operation {
	return t.op
}

// FileStat stores the status of changes in content of a file.
type FileStat struct {
	Name     string
	Addition int
	Deletion int
}

func (fs FileStat) String() string {
	return printStat([]FileStat{fs})
}

// FileStats is a collection of FileStat.
type FileStats []FileStat

func (fileStats FileStats) String() string {
	return printStat(fileStats)
}

func printStat(fileStats []FileStat) string {
	padLength := float64(len(" "))
	newlineLength := float64(len("\n"))
	separatorLength := float64(len("|"))
	// Soft line length limit. The text length calculation below excludes
	// length of the change number. Adding that would take it closer to 80,
	// but probably not more than 80, until it's a huge number.
	lineLength := 72.0

	// Get the longest filename and longest total change.
	var longestLength float64
	var longestTotalChange float64
	for _, fs := range fileStats {
		if int(longestLength) < len(fs.Name) {
			longestLength = float64(len(fs.Name))
		}
		totalChange := fs.Addition + fs.Deletion
		if int(longestTotalChange) < totalChange {
			longestTotalChange = float64(totalChange)
		}
	}

	// Parts of the output:
	// <pad><filename><pad>|<pad><changeNumber><pad><+++/---><newline>
	// example: " main.go | 10 +++++++--- "

	// <pad><filename><pad>
	leftTextLength := padLength + longestLength + padLength

	// <pad><number><pad><+++++/-----><newline>
	// Excluding number length here.
	rightTextLength := padLength + padLength + newlineLength

	totalTextArea := leftTextLength + separatorLength + rightTextLength
	heightOfHistogram := lineLength - totalTextArea

	// Scale the histogram.
	var scaleFactor float64
	if longestTotalChange > heightOfHistogram {
		// Scale down to heightOfHistogram.
		scaleFactor = float64(longestTotalChange / heightOfHistogram)
	} else {
		scaleFactor = 1.0
	}

	finalOutput := ""
	for _, fs := range fileStats {
		addn := float64(fs.Addition)
		deln := float64(fs.Deletion)
		adds := strings.Repeat("+", int(math.Floor(addn/scaleFactor)))
		dels := strings.Repeat("-", int(math.Floor(deln/scaleFactor)))
		finalOutput += fmt.Sprintf(" %s | %d %s%s\n", fs.Name, (fs.Addition + fs.Deletion), adds, dels)
	}

	return finalOutput
}

func getFileStatsFromFilePatches(filePatches []fdiff.FilePatch) FileStats {
	var fileStats FileStats

	for _, fp := range filePatches {
		// ignore empty patches (binary files, submodule refs updates)
		if len(fp.Chunks()) == 0 {
			continue
		}

		cs := FileStat{}
		from, to := fp.Files()
		if from == nil {
			// New File is created.
			cs.Name = to.Path()
		} else if to == nil {
			// File is deleted.
			cs.Name = from.Path()
		} else if from.Path() != to.Path() {
			// File is renamed. Not supported.
			// cs.Name = fmt.Sprintf("%s => %s", from.Path(), to.Path())
		} else {
			cs.Name = from.Path()
		}

		for _, chunk := range fp.Chunks() {
			s := chunk.Content()
			switch chunk.Type() {
			case fdiff.Add:
				cs.Addition += strings.Count(s, "\n")
				if s[len(s)-1] != '\n' {
					cs.Addition++
				}
			case fdiff.Delete:
				cs.Deletion += strings.Count(s, "\n")
				if s[len(s)-1] != '\n' {
					cs.Deletion++
				}
			}
		}

		fileStats = append(fileStats, cs)
	}

	return fileStats
}