diff options
Diffstat (limited to 'vendor/gotest.tools/internal/format/diff.go')
-rw-r--r-- | vendor/gotest.tools/internal/format/diff.go | 161 |
1 files changed, 161 insertions, 0 deletions
diff --git a/vendor/gotest.tools/internal/format/diff.go b/vendor/gotest.tools/internal/format/diff.go new file mode 100644 index 00000000..c938c97b --- /dev/null +++ b/vendor/gotest.tools/internal/format/diff.go @@ -0,0 +1,161 @@ +package format + +import ( + "bytes" + "fmt" + "strings" + "unicode" + + "gotest.tools/internal/difflib" +) + +const ( + contextLines = 2 +) + +// DiffConfig for a unified diff +type DiffConfig struct { + A string + B string + From string + To string +} + +// UnifiedDiff is a modified version of difflib.WriteUnifiedDiff with better +// support for showing the whitespace differences. +func UnifiedDiff(conf DiffConfig) string { + a := strings.SplitAfter(conf.A, "\n") + b := strings.SplitAfter(conf.B, "\n") + groups := difflib.NewMatcher(a, b).GetGroupedOpCodes(contextLines) + if len(groups) == 0 { + return "" + } + + buf := new(bytes.Buffer) + writeFormat := func(format string, args ...interface{}) { + buf.WriteString(fmt.Sprintf(format, args...)) + } + writeLine := func(prefix string, s string) { + buf.WriteString(prefix + s) + } + if hasWhitespaceDiffLines(groups, a, b) { + writeLine = visibleWhitespaceLine(writeLine) + } + formatHeader(writeFormat, conf) + for _, group := range groups { + formatRangeLine(writeFormat, group) + for _, opCode := range group { + in, out := a[opCode.I1:opCode.I2], b[opCode.J1:opCode.J2] + switch opCode.Tag { + case 'e': + formatLines(writeLine, " ", in) + case 'r': + formatLines(writeLine, "-", in) + formatLines(writeLine, "+", out) + case 'd': + formatLines(writeLine, "-", in) + case 'i': + formatLines(writeLine, "+", out) + } + } + } + return buf.String() +} + +// hasWhitespaceDiffLines returns true if any diff groups is only different +// because of whitespace characters. +func hasWhitespaceDiffLines(groups [][]difflib.OpCode, a, b []string) bool { + for _, group := range groups { + in, out := new(bytes.Buffer), new(bytes.Buffer) + for _, opCode := range group { + if opCode.Tag == 'e' { + continue + } + for _, line := range a[opCode.I1:opCode.I2] { + in.WriteString(line) + } + for _, line := range b[opCode.J1:opCode.J2] { + out.WriteString(line) + } + } + if removeWhitespace(in.String()) == removeWhitespace(out.String()) { + return true + } + } + return false +} + +func removeWhitespace(s string) string { + var result []rune + for _, r := range s { + if !unicode.IsSpace(r) { + result = append(result, r) + } + } + return string(result) +} + +func visibleWhitespaceLine(ws func(string, string)) func(string, string) { + mapToVisibleSpace := func(r rune) rune { + switch r { + case '\n': + case ' ': + return '·' + case '\t': + return '▷' + case '\v': + return '▽' + case '\r': + return '↵' + case '\f': + return '↓' + default: + if unicode.IsSpace(r) { + return '�' + } + } + return r + } + return func(prefix, s string) { + ws(prefix, strings.Map(mapToVisibleSpace, s)) + } +} + +func formatHeader(wf func(string, ...interface{}), conf DiffConfig) { + if conf.From != "" || conf.To != "" { + wf("--- %s\n", conf.From) + wf("+++ %s\n", conf.To) + } +} + +func formatRangeLine(wf func(string, ...interface{}), group []difflib.OpCode) { + first, last := group[0], group[len(group)-1] + range1 := formatRangeUnified(first.I1, last.I2) + range2 := formatRangeUnified(first.J1, last.J2) + wf("@@ -%s +%s @@\n", range1, range2) +} + +// Convert range to the "ed" format +func formatRangeUnified(start, stop int) string { + // Per the diff spec at http://www.unix.org/single_unix_specification/ + beginning := start + 1 // lines start numbering with one + length := stop - start + if length == 1 { + return fmt.Sprintf("%d", beginning) + } + if length == 0 { + beginning-- // empty ranges begin at line just before the range + } + return fmt.Sprintf("%d,%d", beginning, length) +} + +func formatLines(writeLine func(string, string), prefix string, lines []string) { + for _, line := range lines { + writeLine(prefix, line) + } + // Add a newline if the last line is missing one so that the diff displays + // properly. + if !strings.HasSuffix(lines[len(lines)-1], "\n") { + writeLine("", "\n") + } +} |