-
Notifications
You must be signed in to change notification settings - Fork 146
/
changes_xpather.go
91 lines (83 loc) · 2.47 KB
/
changes_xpather.go
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
package uast
import (
"bytes"
"io"
"log"
"sort"
"github.com/minio/highwayhash"
"gopkg.in/bblfsh/client-go.v3/tools"
"gopkg.in/bblfsh/sdk.v2/uast/nodes"
"gopkg.in/src-d/go-git.v4/plumbing"
)
// ChangesXPather extracts changed UAST nodes from files changed in the current commit.
type ChangesXPather struct {
XPath string
}
var hashKey = []byte{
0, 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,
}
// Extract returns the list of (inserted, removed) UAST nodes filtered by XPath.
func (xpather ChangesXPather) Extract(changes []Change) ([]nodes.Node, []nodes.Node) {
var resultAdded, resultRemoved []nodes.Node
for _, change := range changes {
if change.After == nil {
continue
}
oldNodes := xpather.filter(change.Before, change.Change.From.TreeEntry.Hash)
newNodes := xpather.filter(change.After, change.Change.To.TreeEntry.Hash)
oldHashes := xpather.hash(oldNodes)
newHashes := xpather.hash(newNodes)
// there can be hash collisions; we ignore them
for hash, node := range newHashes {
if _, exists := oldHashes[hash]; !exists {
resultAdded = append(resultAdded, node)
}
}
for hash, node := range oldHashes {
if _, exists := newHashes[hash]; !exists {
resultRemoved = append(resultRemoved, node)
}
}
}
return resultAdded, resultRemoved
}
func (xpather ChangesXPather) filter(root nodes.Node, origin plumbing.Hash) []nodes.Node {
if root == nil {
return nil
}
filtered, err := tools.Filter(root, xpather.XPath)
if err != nil {
log.Printf("libuast filter error on object %s: %v", origin.String(), err)
return []nodes.Node{}
}
var result []nodes.Node
for filtered.Next() {
result = append(result, filtered.Node().(nodes.Node))
}
return result
}
func (xpather ChangesXPather) hash(nodesToHash []nodes.Node) map[uint64]nodes.Node {
result := map[uint64]nodes.Node{}
for _, node := range nodesToHash {
buffer := &bytes.Buffer{}
stringifyUASTNode(node, buffer)
result[highwayhash.Sum64(buffer.Bytes(), hashKey)] = node
}
return result
}
func stringifyUASTNode(node nodes.Node, writer io.Writer) {
for element := range tools.Iterate(tools.NewIterator(node, tools.PositionOrder)) {
var keys []string
obj := element.(nodes.Object)
for key, val := range obj {
if _, ok := val.(nodes.String); ok {
keys = append(keys, key)
}
}
sort.Strings(keys)
for _, key := range keys {
writer.Write([]byte(key + "=" + string(obj[key].(nodes.String)) + ";"))
}
}
}