Migrate to go-git/go-git v5.0.0 (#10735)

vendor/github.com/go-git/go-git/v5/utils/diff/diff.go

@@ -0,0 +1,61 @@
+// Package diff implements line oriented diffs, similar to the ancient
+// Unix diff command.
+//
+// The current implementation is just a wrapper around Sergi's
+// go-diff/diffmatchpatch library, which is a go port of Neil
+// Fraser's google-diff-match-patch code
+package diff
+
+import (
+	"bytes"
+	"time"
+
+	"github.com/sergi/go-diff/diffmatchpatch"
+)
+
+// Do computes the (line oriented) modifications needed to turn the src
+// string into the dst string. The underlying algorithm is Meyers,
+// its complexity is O(N*d) where N is min(lines(src), lines(dst)) and d
+// is the size of the diff.
+func Do(src, dst string) (diffs []diffmatchpatch.Diff) {
+	// the default timeout is time.Second which may be too small under heavy load
+	return DoWithTimeout(src, dst, time.Hour)
+}
+
+// DoWithTimeout computes the (line oriented) modifications needed to turn the src
+// string into the dst string. The `timeout` argument specifies the maximum
+// amount of time it is allowed to spend in this function. If the timeout
+// is exceeded, the parts of the strings which were not considered are turned into
+// a bulk delete+insert and the half-baked suboptimal result is returned at once.
+// The underlying algorithm is Meyers, its complexity is O(N*d) where N is
+// min(lines(src), lines(dst)) and d is the size of the diff.
+func DoWithTimeout (src, dst string, timeout time.Duration) (diffs []diffmatchpatch.Diff) {
+	dmp := diffmatchpatch.New()
+	dmp.DiffTimeout = timeout
+	wSrc, wDst, warray := dmp.DiffLinesToRunes(src, dst)
+	diffs = dmp.DiffMainRunes(wSrc, wDst, false)
+	diffs = dmp.DiffCharsToLines(diffs, warray)
+	return diffs
+}
+
+// Dst computes and returns the destination text.
+func Dst(diffs []diffmatchpatch.Diff) string {
+	var text bytes.Buffer
+	for _, d := range diffs {
+		if d.Type != diffmatchpatch.DiffDelete {
+			text.WriteString(d.Text)
+		}
+	}
+	return text.String()
+}
+
+// Src computes and returns the source text
+func Src(diffs []diffmatchpatch.Diff) string {
+	var text bytes.Buffer
+	for _, d := range diffs {
+		if d.Type != diffmatchpatch.DiffInsert {
+			text.WriteString(d.Text)
+		}
+	}
+	return text.String()
+}