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
|
package patch
import (
"strings"
"github.com/samber/lo"
)
type patchTransformer struct {
patch *Patch
opts TransformOpts
}
type TransformOpts struct {
// Create a patch that will applied in reverse with `git apply --reverse`.
// This affects how unselected lines are treated when only parts of a hunk
// are selected: usually, for unselected lines we change '-' lines to
// context lines and remove '+' lines, but when Reverse is true we need to
// turn '+' lines into context lines and remove '-' lines.
Reverse bool
// If set, we will replace the original header with one referring to this file name.
// For staging/unstaging lines we don't want the original header because
// it makes git confused e.g. when dealing with deleted/added files
// but with building and applying patches the original header gives git
// information it needs to cleanly apply patches
FileNameOverride string
// Custom patches tend to work better when treating new files as diffs
// against an empty file. The only case where we need this to be false is
// when moving a custom patch to an earlier commit; in that case the patch
// command would fail with the error "file does not exist in index" if we
// treat it as a diff against an empty file.
TurnAddedFilesIntoDiffAgainstEmptyFile bool
// The indices of lines that should be included in the patch.
IncludedLineIndices []int
}
func transform(patch *Patch, opts TransformOpts) *Patch {
transformer := &patchTransformer{
patch: patch,
opts: opts,
}
return transformer.transform()
}
// helper function that takes a start and end index and returns a slice of all
// indexes inbetween (inclusive)
func ExpandRange(start int, end int) []int {
expanded := []int{}
for i := start; i <= end; i++ {
expanded = append(expanded, i)
}
return expanded
}
func (self *patchTransformer) transform() *Patch {
header := self.transformHeader()
hunks := self.transformHunks()
return &Patch{
header: header,
hunks: hunks,
}
}
func (self *patchTransformer) transformHeader() []string {
if self.opts.FileNameOverride != "" {
return []string{
"--- a/" + self.opts.FileNameOverride,
"+++ b/" + self.opts.FileNameOverride,
}
} else if self.opts.TurnAddedFilesIntoDiffAgainstEmptyFile {
result := make([]string, 0, len(self.patch.header))
for idx, line := range self.patch.header {
if strings.HasPrefix(line, "new file mode") {
continue
}
if line == "--- /dev/null" && strings.HasPrefix(self.patch.header[idx+1], "+++ b/") {
line = "--- a/" + self.patch.header[idx+1][6:]
}
result = append(result, line)
}
return result
} else {
return self.patch.header
}
}
func (self *patchTransformer) transformHunks() []*Hunk {
newHunks := make([]*Hunk, 0, len(self.patch.hunks))
startOffset := 0
var formattedHunk *Hunk
for i, hunk := range self.patch.hunks {
startOffset, formattedHunk = self.transformHunk(
hunk,
startOffset,
self.patch.HunkStartIdx(i),
)
if formattedHunk.containsChanges() {
newHunks = append(newHunks, formattedHunk)
}
}
return newHunks
}
func (self *patchTransformer) transformHunk(hunk *Hunk, startOffset int, firstLineIdx int) (int, *Hunk) {
newLines := self.transformHunkLines(hunk, firstLineIdx)
newNewStart, newStartOffset := self.transformHunkHeader(newLines, hunk.oldStart, startOffset)
newHunk := &Hunk{
bodyLines: newLines,
oldStart: hunk.oldStart,
newStart: newNewStart,
headerContext: hunk.headerContext,
}
return newStartOffset, newHunk
}
func (self *patchTransformer) transformHunkLines(hunk *Hunk, firstLineIdx int) []*PatchLine {
skippedNewlineMessageIndex := -1
newLines := []*PatchLine{}
for i, line := range hunk.bodyLines {
lineIdx := i + firstLineIdx + 1 // plus one for header line
if line.Content == "" {
break
}
isLineSelected := lo.Contains(self.opts.IncludedLineIndices, lineIdx)
if isLineSelected || (line.Kind == NEWLINE_MESSAGE && skippedNewlineMessageIndex != lineIdx) || line.Kind == CONTEXT {
newLines = append(newLines, line)
continue
}
if (line.Kind == DELETION && !self.opts.Reverse) || (line.Kind == ADDITION && self.opts.Reverse) {
content := " " + line.Content[1:]
newLines = append(newLines, &PatchLine{
Kind: CONTEXT,
Content: content,
})
continue
}
if line.Kind == ADDITION {
// we don't want to include the 'newline at end of file' line if it involves an addition we're not including
skippedNewlineMessageIndex = lineIdx + 1
}
}
return newLines
}
func (self *patchTransformer) transformHunkHeader(newBodyLines []*PatchLine, oldStart int, startOffset int) (int, int) {
oldLength := nLinesWithKind(newBodyLines, []PatchLineKind{CONTEXT, DELETION})
newLength := nLinesWithKind(newBodyLines, []PatchLineKind{CONTEXT, ADDITION})
var newStartOffset int
// if the hunk went from zero to positive length, we need to increment the starting point by one
// if the hunk went from positive to zero length, we need to decrement the starting point by one
if oldLength == 0 {
newStartOffset = 1
} else if newLength == 0 {
newStartOffset = -1
} else {
newStartOffset = 0
}
newStart := oldStart + startOffset + newStartOffset
newStartOffset = startOffset + newLength - oldLength
return newStart, newStartOffset
}
|
