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Add missing go-difflib vendoring

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Signed-off-by: Kenfe-Mickael Laventure <mickael.laventure@gmail.com>
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Kenfe-Mickael Laventure 2017-05-15 11:23:52 -07:00
parent 0ea0b2becf
commit 8c340b7edf
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1
vendor.conf
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@ -19,6 +19,7 @@ github.com/docker/go-units 9e638d38cf6977a37a8ea0078f3ee75a7cdb2dd1
github.com/docker/go-connections e15c02316c12de00874640cd76311849de2aeed5
golang.org/x/text f72d8390a633d5dfb0cc84043294db9f6c935756
github.com/stretchr/testify 4d4bfba8f1d1027c4fdbe371823030df51419987
github.com/pmezard/go-difflib v1.0.0
github.com/RackSec/srslog 456df3a81436d29ba874f3590eeeee25d666f8a5
github.com/imdario/mergo 0.2.1

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vendor/github.com/pmezard/go-difflib/LICENSE generated vendored Normal file
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@ -0,0 +1,27 @@
Copyright (c) 2013, Patrick Mezard
All rights reserved.
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are
met:
Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.
Redistributions in binary form must reproduce the above copyright
notice, this list of conditions and the following disclaimer in the
documentation and/or other materials provided with the distribution.
The names of its contributors may not be used to endorse or promote
products derived from this software without specific prior written
permission.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

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vendor/github.com/pmezard/go-difflib/README.md generated vendored Normal file
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go-difflib
==========
[![Build Status](https://travis-ci.org/pmezard/go-difflib.png?branch=master)](https://travis-ci.org/pmezard/go-difflib)
[![GoDoc](https://godoc.org/github.com/pmezard/go-difflib/difflib?status.svg)](https://godoc.org/github.com/pmezard/go-difflib/difflib)
Go-difflib is a partial port of python 3 difflib package. Its main goal
was to make unified and context diff available in pure Go, mostly for
testing purposes.
The following class and functions (and related tests) have be ported:
* `SequenceMatcher`
* `unified_diff()`
* `context_diff()`
## Installation
```bash
$ go get github.com/pmezard/go-difflib/difflib
```
### Quick Start
Diffs are configured with Unified (or ContextDiff) structures, and can
be output to an io.Writer or returned as a string.
```Go
diff := UnifiedDiff{
A: difflib.SplitLines("foo\nbar\n"),
B: difflib.SplitLines("foo\nbaz\n"),
FromFile: "Original",
ToFile: "Current",
Context: 3,
}
text, _ := GetUnifiedDiffString(diff)
fmt.Printf(text)
```
would output:
```
--- Original
+++ Current
@@ -1,3 +1,3 @@
foo
-bar
+baz
```

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vendor/github.com/pmezard/go-difflib/difflib/difflib.go generated vendored Normal file
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// Package difflib is a partial port of Python difflib module.
//
// It provides tools to compare sequences of strings and generate textual diffs.
//
// The following class and functions have been ported:
//
// - SequenceMatcher
//
// - unified_diff
//
// - context_diff
//
// Getting unified diffs was the main goal of the port. Keep in mind this code
// is mostly suitable to output text differences in a human friendly way, there
// are no guarantees generated diffs are consumable by patch(1).
package difflib
import (
"bufio"
"bytes"
"fmt"
"io"
"strings"
)
func min(a, b int) int {
if a < b {
return a
}
return b
}
func max(a, b int) int {
if a > b {
return a
}
return b
}
func calculateRatio(matches, length int) float64 {
if length > 0 {
return 2.0 * float64(matches) / float64(length)
}
return 1.0
}
type Match struct {
A int
B int
Size int
}
type OpCode struct {
Tag byte
I1 int
I2 int
J1 int
J2 int
}
// SequenceMatcher compares sequence of strings. The basic
// algorithm predates, and is a little fancier than, an algorithm
// published in the late 1980's by Ratcliff and Obershelp under the
// hyperbolic name "gestalt pattern matching". The basic idea is to find
// the longest contiguous matching subsequence that contains no "junk"
// elements (R-O doesn't address junk). The same idea is then applied
// recursively to the pieces of the sequences to the left and to the right
// of the matching subsequence. This does not yield minimal edit
// sequences, but does tend to yield matches that "look right" to people.
//
// SequenceMatcher tries to compute a "human-friendly diff" between two
// sequences. Unlike e.g. UNIX(tm) diff, the fundamental notion is the
// longest *contiguous* & junk-free matching subsequence. That's what
// catches peoples' eyes. The Windows(tm) windiff has another interesting
// notion, pairing up elements that appear uniquely in each sequence.
// That, and the method here, appear to yield more intuitive difference
// reports than does diff. This method appears to be the least vulnerable
// to synching up on blocks of "junk lines", though (like blank lines in
// ordinary text files, or maybe "<P>" lines in HTML files). That may be
// because this is the only method of the 3 that has a *concept* of
// "junk" <wink>.
//
// Timing: Basic R-O is cubic time worst case and quadratic time expected
// case. SequenceMatcher is quadratic time for the worst case and has
// expected-case behavior dependent in a complicated way on how many
// elements the sequences have in common; best case time is linear.
type SequenceMatcher struct {
a []string
b []string
b2j map[string][]int
IsJunk func(string) bool
autoJunk bool
bJunk map[string]struct{}
matchingBlocks []Match
fullBCount map[string]int
bPopular map[string]struct{}
opCodes []OpCode
}
func NewMatcher(a, b []string) *SequenceMatcher {
m := SequenceMatcher{autoJunk: true}
m.SetSeqs(a, b)
return &m
}
func NewMatcherWithJunk(a, b []string, autoJunk bool,
isJunk func(string) bool) *SequenceMatcher {
m := SequenceMatcher{IsJunk: isJunk, autoJunk: autoJunk}
m.SetSeqs(a, b)
return &m
}
// Set two sequences to be compared.
func (m *SequenceMatcher) SetSeqs(a, b []string) {
m.SetSeq1(a)
m.SetSeq2(b)
}
// Set the first sequence to be compared. The second sequence to be compared is
// not changed.
//
// SequenceMatcher computes and caches detailed information about the second
// sequence, so if you want to compare one sequence S against many sequences,
// use .SetSeq2(s) once and call .SetSeq1(x) repeatedly for each of the other
// sequences.
//
// See also SetSeqs() and SetSeq2().
func (m *SequenceMatcher) SetSeq1(a []string) {
if &a == &m.a {
return
}
m.a = a
m.matchingBlocks = nil
m.opCodes = nil
}
// Set the second sequence to be compared. The first sequence to be compared is
// not changed.
func (m *SequenceMatcher) SetSeq2(b []string) {
if &b == &m.b {
return
}
m.b = b
m.matchingBlocks = nil
m.opCodes = nil
m.fullBCount = nil
m.chainB()
}
func (m *SequenceMatcher) chainB() {
// Populate line -> index mapping
b2j := map[string][]int{}
for i, s := range m.b {
indices := b2j[s]
indices = append(indices, i)
b2j[s] = indices
}
// Purge junk elements
m.bJunk = map[string]struct{}{}
if m.IsJunk != nil {
junk := m.bJunk
for s, _ := range b2j {
if m.IsJunk(s) {
junk[s] = struct{}{}
}
}
for s, _ := range junk {
delete(b2j, s)
}
}
// Purge remaining popular elements
popular := map[string]struct{}{}
n := len(m.b)
if m.autoJunk && n >= 200 {
ntest := n/100 + 1
for s, indices := range b2j {
if len(indices) > ntest {
popular[s] = struct{}{}
}
}
for s, _ := range popular {
delete(b2j, s)
}
}
m.bPopular = popular
m.b2j = b2j
}
func (m *SequenceMatcher) isBJunk(s string) bool {
_, ok := m.bJunk[s]
return ok
}
// Find longest matching block in a[alo:ahi] and b[blo:bhi].
//
// If IsJunk is not defined:
//
// Return (i,j,k) such that a[i:i+k] is equal to b[j:j+k], where
// alo <= i <= i+k <= ahi
// blo <= j <= j+k <= bhi
// and for all (i',j',k') meeting those conditions,
// k >= k'
// i <= i'
// and if i == i', j <= j'
//
// In other words, of all maximal matching blocks, return one that
// starts earliest in a, and of all those maximal matching blocks that
// start earliest in a, return the one that starts earliest in b.
//
// If IsJunk is defined, first the longest matching block is
// determined as above, but with the additional restriction that no
// junk element appears in the block. Then that block is extended as
// far as possible by matching (only) junk elements on both sides. So
// the resulting block never matches on junk except as identical junk
// happens to be adjacent to an "interesting" match.
//
// If no blocks match, return (alo, blo, 0).
func (m *SequenceMatcher) findLongestMatch(alo, ahi, blo, bhi int) Match {
// CAUTION: stripping common prefix or suffix would be incorrect.
// E.g.,
// ab
// acab
// Longest matching block is "ab", but if common prefix is
// stripped, it's "a" (tied with "b"). UNIX(tm) diff does so
// strip, so ends up claiming that ab is changed to acab by
// inserting "ca" in the middle. That's minimal but unintuitive:
// "it's obvious" that someone inserted "ac" at the front.
// Windiff ends up at the same place as diff, but by pairing up
// the unique 'b's and then matching the first two 'a's.
besti, bestj, bestsize := alo, blo, 0
// find longest junk-free match
// during an iteration of the loop, j2len[j] = length of longest
// junk-free match ending with a[i-1] and b[j]
j2len := map[int]int{}
for i := alo; i != ahi; i++ {
// look at all instances of a[i] in b; note that because
// b2j has no junk keys, the loop is skipped if a[i] is junk
newj2len := map[int]int{}
for _, j := range m.b2j[m.a[i]] {
// a[i] matches b[j]
if j < blo {
continue
}
if j >= bhi {
break
}
k := j2len[j-1] + 1
newj2len[j] = k
if k > bestsize {
besti, bestj, bestsize = i-k+1, j-k+1, k
}
}
j2len = newj2len
}
// Extend the best by non-junk elements on each end. In particular,
// "popular" non-junk elements aren't in b2j, which greatly speeds
// the inner loop above, but also means "the best" match so far
// doesn't contain any junk *or* popular non-junk elements.
for besti > alo && bestj > blo && !m.isBJunk(m.b[bestj-1]) &&
m.a[besti-1] == m.b[bestj-1] {
besti, bestj, bestsize = besti-1, bestj-1, bestsize+1
}
for besti+bestsize < ahi && bestj+bestsize < bhi &&
!m.isBJunk(m.b[bestj+bestsize]) &&
m.a[besti+bestsize] == m.b[bestj+bestsize] {
bestsize += 1
}
// Now that we have a wholly interesting match (albeit possibly
// empty!), we may as well suck up the matching junk on each
// side of it too. Can't think of a good reason not to, and it
// saves post-processing the (possibly considerable) expense of
// figuring out what to do with it. In the case of an empty
// interesting match, this is clearly the right thing to do,
// because no other kind of match is possible in the regions.
for besti > alo && bestj > blo && m.isBJunk(m.b[bestj-1]) &&
m.a[besti-1] == m.b[bestj-1] {
besti, bestj, bestsize = besti-1, bestj-1, bestsize+1
}
for besti+bestsize < ahi && bestj+bestsize < bhi &&
m.isBJunk(m.b[bestj+bestsize]) &&
m.a[besti+bestsize] == m.b[bestj+bestsize] {
bestsize += 1
}
return Match{A: besti, B: bestj, Size: bestsize}
}
// Return list of triples describing matching subsequences.
//
// Each triple is of the form (i, j, n), and means that
// a[i:i+n] == b[j:j+n]. The triples are monotonically increasing in
// i and in j. It's also guaranteed that if (i, j, n) and (i', j', n') are
// adjacent triples in the list, and the second is not the last triple in the
// list, then i+n != i' or j+n != j'. IOW, adjacent triples never describe
// adjacent equal blocks.
//
// The last triple is a dummy, (len(a), len(b), 0), and is the only
// triple with n==0.
func (m *SequenceMatcher) GetMatchingBlocks() []Match {
if m.matchingBlocks != nil {
return m.matchingBlocks
}
var matchBlocks func(alo, ahi, blo, bhi int, matched []Match) []Match
matchBlocks = func(alo, ahi, blo, bhi int, matched []Match) []Match {
match := m.findLongestMatch(alo, ahi, blo, bhi)
i, j, k := match.A, match.B, match.Size
if match.Size > 0 {
if alo < i && blo < j {
matched = matchBlocks(alo, i, blo, j, matched)
}
matched = append(matched, match)
if i+k < ahi && j+k < bhi {
matched = matchBlocks(i+k, ahi, j+k, bhi, matched)
}
}
return matched
}
matched := matchBlocks(0, len(m.a), 0, len(m.b), nil)
// It's possible that we have adjacent equal blocks in the
// matching_blocks list now.
nonAdjacent := []Match{}
i1, j1, k1 := 0, 0, 0
for _, b := range matched {
// Is this block adjacent to i1, j1, k1?
i2, j2, k2 := b.A, b.B, b.Size
if i1+k1 == i2 && j1+k1 == j2 {
// Yes, so collapse them -- this just increases the length of
// the first block by the length of the second, and the first
// block so lengthened remains the block to compare against.
k1 += k2
} else {
// Not adjacent. Remember the first block (k1==0 means it's
// the dummy we started with), and make the second block the
// new block to compare against.
if k1 > 0 {
nonAdjacent = append(nonAdjacent, Match{i1, j1, k1})
}
i1, j1, k1 = i2, j2, k2
}
}
if k1 > 0 {
nonAdjacent = append(nonAdjacent, Match{i1, j1, k1})
}
nonAdjacent = append(nonAdjacent, Match{len(m.a), len(m.b), 0})
m.matchingBlocks = nonAdjacent
return m.matchingBlocks
}
// Return list of 5-tuples describing how to turn a into b.
//
// Each tuple is of the form (tag, i1, i2, j1, j2). The first tuple
// has i1 == j1 == 0, and remaining tuples have i1 == the i2 from the
// tuple preceding it, and likewise for j1 == the previous j2.
//
// The tags are characters, with these meanings:
//
// 'r' (replace): a[i1:i2] should be replaced by b[j1:j2]
//
// 'd' (delete): a[i1:i2] should be deleted, j1==j2 in this case.
//
// 'i' (insert): b[j1:j2] should be inserted at a[i1:i1], i1==i2 in this case.
//
// 'e' (equal): a[i1:i2] == b[j1:j2]
func (m *SequenceMatcher) GetOpCodes() []OpCode {
if m.opCodes != nil {
return m.opCodes
}
i, j := 0, 0
matching := m.GetMatchingBlocks()
opCodes := make([]OpCode, 0, len(matching))
for _, m := range matching {
// invariant: we've pumped out correct diffs to change
// a[:i] into b[:j], and the next matching block is
// a[ai:ai+size] == b[bj:bj+size]. So we need to pump
// out a diff to change a[i:ai] into b[j:bj], pump out
// the matching block, and move (i,j) beyond the match
ai, bj, size := m.A, m.B, m.Size
tag := byte(0)
if i < ai && j < bj {
tag = 'r'
} else if i < ai {
tag = 'd'
} else if j < bj {
tag = 'i'
}
if tag > 0 {
opCodes = append(opCodes, OpCode{tag, i, ai, j, bj})
}
i, j = ai+size, bj+size
// the list of matching blocks is terminated by a
// sentinel with size 0
if size > 0 {
opCodes = append(opCodes, OpCode{'e', ai, i, bj, j})
}
}
m.opCodes = opCodes
return m.opCodes
}
// Isolate change clusters by eliminating ranges with no changes.
//
// Return a generator of groups with up to n lines of context.
// Each group is in the same format as returned by GetOpCodes().
func (m *SequenceMatcher) GetGroupedOpCodes(n int) [][]OpCode {
if n < 0 {
n = 3
}
codes := m.GetOpCodes()
if len(codes) == 0 {
codes = []OpCode{OpCode{'e', 0, 1, 0, 1}}
}
// Fixup leading and trailing groups if they show no changes.
if codes[0].Tag == 'e' {
c := codes[0]
i1, i2, j1, j2 := c.I1, c.I2, c.J1, c.J2
codes[0] = OpCode{c.Tag, max(i1, i2-n), i2, max(j1, j2-n), j2}
}
if codes[len(codes)-1].Tag == 'e' {
c := codes[len(codes)-1]
i1, i2, j1, j2 := c.I1, c.I2, c.J1, c.J2
codes[len(codes)-1] = OpCode{c.Tag, i1, min(i2, i1+n), j1, min(j2, j1+n)}
}
nn := n + n
groups := [][]OpCode{}
group := []OpCode{}
for _, c := range codes {
i1, i2, j1, j2 := c.I1, c.I2, c.J1, c.J2
// End the current group and start a new one whenever
// there is a large range with no changes.
if c.Tag == 'e' && i2-i1 > nn {
group = append(group, OpCode{c.Tag, i1, min(i2, i1+n),
j1, min(j2, j1+n)})
groups = append(groups, group)
group = []OpCode{}
i1, j1 = max(i1, i2-n), max(j1, j2-n)
}
group = append(group, OpCode{c.Tag, i1, i2, j1, j2})
}
if len(group) > 0 && !(len(group) == 1 && group[0].Tag == 'e') {
groups = append(groups, group)
}
return groups
}
// Return a measure of the sequences' similarity (float in [0,1]).
//
// Where T is the total number of elements in both sequences, and
// M is the number of matches, this is 2.0*M / T.
// Note that this is 1 if the sequences are identical, and 0 if
// they have nothing in common.
//
// .Ratio() is expensive to compute if you haven't already computed
// .GetMatchingBlocks() or .GetOpCodes(), in which case you may
// want to try .QuickRatio() or .RealQuickRation() first to get an
// upper bound.
func (m *SequenceMatcher) Ratio() float64 {
matches := 0
for _, m := range m.GetMatchingBlocks() {
matches += m.Size
}
return calculateRatio(matches, len(m.a)+len(m.b))
}
// Return an upper bound on ratio() relatively quickly.
//
// This isn't defined beyond that it is an upper bound on .Ratio(), and
// is faster to compute.
func (m *SequenceMatcher) QuickRatio() float64 {
// viewing a and b as multisets, set matches to the cardinality
// of their intersection; this counts the number of matches
// without regard to order, so is clearly an upper bound
if m.fullBCount == nil {
m.fullBCount = map[string]int{}
for _, s := range m.b {
m.fullBCount[s] = m.fullBCount[s] + 1
}
}
// avail[x] is the number of times x appears in 'b' less the
// number of times we've seen it in 'a' so far ... kinda
avail := map[string]int{}
matches := 0
for _, s := range m.a {
n, ok := avail[s]
if !ok {
n = m.fullBCount[s]
}
avail[s] = n - 1
if n > 0 {
matches += 1
}
}
return calculateRatio(matches, len(m.a)+len(m.b))
}
// Return an upper bound on ratio() very quickly.
//
// This isn't defined beyond that it is an upper bound on .Ratio(), and
// is faster to compute than either .Ratio() or .QuickRatio().
func (m *SequenceMatcher) RealQuickRatio() float64 {
la, lb := len(m.a), len(m.b)
return calculateRatio(min(la, lb), la+lb)
}
// 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 -= 1 // empty ranges begin at line just before the range
}
return fmt.Sprintf("%d,%d", beginning, length)
}
// Unified diff parameters
type UnifiedDiff struct {
A []string // First sequence lines
FromFile string // First file name
FromDate string // First file time
B []string // Second sequence lines
ToFile string // Second file name
ToDate string // Second file time
Eol string // Headers end of line, defaults to LF
Context int // Number of context lines
}
// Compare two sequences of lines; generate the delta as a unified diff.
//
// Unified diffs are a compact way of showing line changes and a few
// lines of context. The number of context lines is set by 'n' which
// defaults to three.
//
// By default, the diff control lines (those with ---, +++, or @@) are
// created with a trailing newline. This is helpful so that inputs
// created from file.readlines() result in diffs that are suitable for
// file.writelines() since both the inputs and outputs have trailing
// newlines.
//
// For inputs that do not have trailing newlines, set the lineterm
// argument to "" so that the output will be uniformly newline free.
//
// The unidiff format normally has a header for filenames and modification
// times. Any or all of these may be specified using strings for
// 'fromfile', 'tofile', 'fromfiledate', and 'tofiledate'.
// The modification times are normally expressed in the ISO 8601 format.
func WriteUnifiedDiff(writer io.Writer, diff UnifiedDiff) error {
buf := bufio.NewWriter(writer)
defer buf.Flush()
wf := func(format string, args ...interface{}) error {
_, err := buf.WriteString(fmt.Sprintf(format, args...))
return err
}
ws := func(s string) error {
_, err := buf.WriteString(s)
return err
}
if len(diff.Eol) == 0 {
diff.Eol = "\n"
}
started := false
m := NewMatcher(diff.A, diff.B)
for _, g := range m.GetGroupedOpCodes(diff.Context) {
if !started {
started = true
fromDate := ""
if len(diff.FromDate) > 0 {
fromDate = "\t" + diff.FromDate
}
toDate := ""
if len(diff.ToDate) > 0 {
toDate = "\t" + diff.ToDate
}
if diff.FromFile != "" || diff.ToFile != "" {
err := wf("--- %s%s%s", diff.FromFile, fromDate, diff.Eol)
if err != nil {
return err
}
err = wf("+++ %s%s%s", diff.ToFile, toDate, diff.Eol)
if err != nil {
return err
}
}
}
first, last := g[0], g[len(g)-1]
range1 := formatRangeUnified(first.I1, last.I2)
range2 := formatRangeUnified(first.J1, last.J2)
if err := wf("@@ -%s +%s @@%s", range1, range2, diff.Eol); err != nil {
return err
}
for _, c := range g {
i1, i2, j1, j2 := c.I1, c.I2, c.J1, c.J2
if c.Tag == 'e' {
for _, line := range diff.A[i1:i2] {
if err := ws(" " + line); err != nil {
return err
}
}
continue
}
if c.Tag == 'r' || c.Tag == 'd' {
for _, line := range diff.A[i1:i2] {
if err := ws("-" + line); err != nil {
return err
}
}
}
if c.Tag == 'r' || c.Tag == 'i' {
for _, line := range diff.B[j1:j2] {
if err := ws("+" + line); err != nil {
return err
}
}
}
}
}
return nil
}
// Like WriteUnifiedDiff but returns the diff a string.
func GetUnifiedDiffString(diff UnifiedDiff) (string, error) {
w := &bytes.Buffer{}
err := WriteUnifiedDiff(w, diff)
return string(w.Bytes()), err
}
// Convert range to the "ed" format.
func formatRangeContext(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 == 0 {
beginning -= 1 // empty ranges begin at line just before the range
}
if length <= 1 {
return fmt.Sprintf("%d", beginning)
}
return fmt.Sprintf("%d,%d", beginning, beginning+length-1)
}
type ContextDiff UnifiedDiff
// Compare two sequences of lines; generate the delta as a context diff.
//
// Context diffs are a compact way of showing line changes and a few
// lines of context. The number of context lines is set by diff.Context
// which defaults to three.
//
// By default, the diff control lines (those with *** or ---) are
// created with a trailing newline.
//
// For inputs that do not have trailing newlines, set the diff.Eol
// argument to "" so that the output will be uniformly newline free.
//
// The context diff format normally has a header for filenames and
// modification times. Any or all of these may be specified using
// strings for diff.FromFile, diff.ToFile, diff.FromDate, diff.ToDate.
// The modification times are normally expressed in the ISO 8601 format.
// If not specified, the strings default to blanks.
func WriteContextDiff(writer io.Writer, diff ContextDiff) error {
buf := bufio.NewWriter(writer)
defer buf.Flush()
var diffErr error
wf := func(format string, args ...interface{}) {
_, err := buf.WriteString(fmt.Sprintf(format, args...))
if diffErr == nil && err != nil {
diffErr = err
}
}
ws := func(s string) {
_, err := buf.WriteString(s)
if diffErr == nil && err != nil {
diffErr = err
}
}
if len(diff.Eol) == 0 {
diff.Eol = "\n"
}
prefix := map[byte]string{
'i': "+ ",
'd': "- ",
'r': "! ",
'e': " ",
}
started := false
m := NewMatcher(diff.A, diff.B)
for _, g := range m.GetGroupedOpCodes(diff.Context) {
if !started {
started = true
fromDate := ""
if len(diff.FromDate) > 0 {
fromDate = "\t" + diff.FromDate
}
toDate := ""
if len(diff.ToDate) > 0 {
toDate = "\t" + diff.ToDate
}
if diff.FromFile != "" || diff.ToFile != "" {
wf("*** %s%s%s", diff.FromFile, fromDate, diff.Eol)
wf("--- %s%s%s", diff.ToFile, toDate, diff.Eol)
}
}
first, last := g[0], g[len(g)-1]
ws("***************" + diff.Eol)
range1 := formatRangeContext(first.I1, last.I2)
wf("*** %s ****%s", range1, diff.Eol)
for _, c := range g {
if c.Tag == 'r' || c.Tag == 'd' {
for _, cc := range g {
if cc.Tag == 'i' {
continue
}
for _, line := range diff.A[cc.I1:cc.I2] {
ws(prefix[cc.Tag] + line)
}
}
break
}
}
range2 := formatRangeContext(first.J1, last.J2)
wf("--- %s ----%s", range2, diff.Eol)
for _, c := range g {
if c.Tag == 'r' || c.Tag == 'i' {
for _, cc := range g {
if cc.Tag == 'd' {
continue
}
for _, line := range diff.B[cc.J1:cc.J2] {
ws(prefix[cc.Tag] + line)
}
}
break
}
}
}
return diffErr
}
// Like WriteContextDiff but returns the diff a string.
func GetContextDiffString(diff ContextDiff) (string, error) {
w := &bytes.Buffer{}
err := WriteContextDiff(w, diff)
return string(w.Bytes()), err
}
// Split a string on "\n" while preserving them. The output can be used
// as input for UnifiedDiff and ContextDiff structures.
func SplitLines(s string) []string {
lines := strings.SplitAfter(s, "\n")
lines[len(lines)-1] += "\n"
return lines
}