Merge pull request #24 from anguslees/diff

Implement diff subcommand

cmd/delete.go

@@ -2,6 +2,7 @@ package cmd
 
 import (
 	"fmt"
+	"sort"
 
 	"github.com/golang/glog"
 	"github.com/spf13/cobra"
@@ -44,7 +45,7 @@ var deleteCmd = &cobra.Command{
 
 		defaultNs, _, err := clientConfig.Namespace()
 
-		utils.SortDepLast(objs)
+		sort.Sort(sort.Reverse(utils.DependencyOrder(objs)))
 
 		deleteOpts := v1.DeleteOptions{OrphanDependents: &boolFalse}
 		if gracePeriod >= 0 {

cmd/diff.go

+package cmd
+
+import (
+	"fmt"
+	"io"
+	"os"
+	"sort"
+
+	"github.com/golang/glog"
+	"github.com/mattn/go-isatty"
+	"github.com/spf13/cobra"
+	"github.com/yudai/gojsondiff"
+	"github.com/yudai/gojsondiff/formatter"
+	"k8s.io/client-go/pkg/api/errors"
+
+	"github.com/ksonnet/kubecfg/utils"
+)
+
+func init() {
+	RootCmd.AddCommand(diffCmd)
+}
+
+var diffCmd = &cobra.Command{
+	Use:   "diff",
+	Short: "Display differences between server and local config",
+	RunE: func(cmd *cobra.Command, args []string) error {
+		out := cmd.OutOrStdout()
+
+		objs, err := readObjs(cmd, args)
+		if err != nil {
+			return err
+		}
+
+		clientpool, disco, err := restClientPool(cmd)
+		if err != nil {
+			return err
+		}
+
+		defaultNs, _, err := clientConfig.Namespace()
+		if err != nil {
+			return err
+		}
+
+		sort.Sort(utils.AlphabeticalOrder(objs))
+
+		for _, obj := range objs {
+			desc := fmt.Sprintf("%s/%s", obj.GetKind(), fqName(obj))
+			glog.V(2).Info("Fetching ", desc)
+
+			c, err := clientForResource(clientpool, disco, obj, defaultNs)
+			if err != nil {
+				return err
+			}
+
+			liveObj, err := c.Get(obj.GetName())
+			if err != nil && errors.IsNotFound(err) {
+				glog.V(2).Infof("%s doesn't exist on the server", desc)
+				liveObj = nil
+			} else if err != nil {
+				return fmt.Errorf("Error fetching %s: %v", desc, err)
+			}
+
+			fmt.Fprintln(out, "---")
+			fmt.Fprintf(out, "- live %s\n+ config %s", desc, desc)
+			if liveObj == nil {
+				fmt.Fprintf(out, "%s doesn't exist on server\n", desc)
+				continue
+			}
+
+			diff := gojsondiff.New().CompareObjects(liveObj.Object, obj.Object)
+
+			if diff.Modified() {
+				fcfg := formatter.AsciiFormatterConfig{
+					Coloring: istty(out),
+				}
+				formatter := formatter.NewAsciiFormatter(liveObj.Object, fcfg)
+				text, err := formatter.Format(diff)
+				if err != nil {
+					return err
+				}
+				fmt.Fprintf(out, "%s", text)
+			} else {
+				fmt.Fprintf(out, "%s unchanged\n", desc)
+			}
+		}
+
+		return nil
+	},
+}
+
+func istty(w io.Writer) bool {
+	if f, ok := w.(*os.File); ok {
+		return isatty.IsTerminal(f.Fd())
+	}
+	return false
+}

cmd/update.go

@@ -3,6 +3,7 @@ package cmd
 import (
 	"encoding/json"
 	"fmt"
+	"sort"
 
 	"github.com/golang/glog"
 	"github.com/spf13/cobra"
@@ -49,7 +50,7 @@ var updateCmd = &cobra.Command{
 			return err
 		}
 
-		utils.SortDepFirst(objs)
+		sort.Sort(utils.DependencyOrder(objs))
 
 		for _, obj := range objs {
 			desc := fmt.Sprintf("%s/%s", obj.GetKind(), fqName(obj))

utils/sort.go

 package utils
 
 import (
-	"sort"
-
 	"k8s.io/client-go/pkg/api/unversioned"
 	"k8s.io/client-go/pkg/runtime"
 )
@@ -42,23 +40,32 @@ func depTier(o *runtime.Unstructured) int {
 	}
 }
 
-type dependentObjects []*runtime.Unstructured
+// DependencyOrder is a `sort.Interface` that *best-effort* sorts the
+// objects so that known dependencies appear earlier in the list.  The
+// idea is to prevent *some* of the "crash-restart" loops when
+// creating inter-dependent resources.
+type DependencyOrder []*runtime.Unstructured
 
-func (l dependentObjects) Len() int      { return len(l) }
-func (l dependentObjects) Swap(i, j int) { l[i], l[j] = l[j], l[i] }
-func (l dependentObjects) Less(i, j int) bool {
+func (l DependencyOrder) Len() int      { return len(l) }
+func (l DependencyOrder) Swap(i, j int) { l[i], l[j] = l[j], l[i] }
+func (l DependencyOrder) Less(i, j int) bool {
 	return depTier(l[i]) < depTier(l[j])
 }
 
-// SortDepFirst *best-effort* sorts the objects so that known
-// dependencies appear earlier in the list.  The idea is to prevent
-// *some* of the "crash-restart" loops when creating inter-dependent
-// resources.
-func SortDepFirst(objs []*runtime.Unstructured) {
-	sort.Sort(dependentObjects(objs))
-}
+// AlphabeticalOrder is a `sort.Interface` that sorts the
+// objects by namespace/name/kind alphabetical order
+type AlphabeticalOrder []*runtime.Unstructured
+
+func (l AlphabeticalOrder) Len() int      { return len(l) }
+func (l AlphabeticalOrder) Swap(i, j int) { l[i], l[j] = l[j], l[i] }
+func (l AlphabeticalOrder) Less(i, j int) bool {
+	a, b := l[i], l[j]
 
-// SortDepLast is the reverse order of SortDepFirst.
-func SortDepLast(objs []*runtime.Unstructured) {
-	sort.Sort(sort.Reverse(dependentObjects(objs)))
+	if a.GetNamespace() != b.GetNamespace() {
+		return a.GetNamespace() < b.GetNamespace()
+	}
+	if a.GetName() != b.GetName() {
+		return a.GetName() < b.GetName()
+	}
+	return a.GetKind() < b.GetKind()
 }

utils/sort_test.go

 package utils
 
 import (
+	"reflect"
+	"sort"
 	"testing"
 
 	"k8s.io/client-go/pkg/runtime"
 )
 
-func newObj(apiVersion, kind string) *runtime.Unstructured {
-	return &runtime.Unstructured{
-		Object: map[string]interface{}{
-			"apiVersion": apiVersion,
-			"kind":       kind,
-		},
+var _ sort.Interface = DependencyOrder{}
+
+func TestDepSort(t *testing.T) {
+	newObj := func(apiVersion, kind string) *runtime.Unstructured {
+		return &runtime.Unstructured{
+			Object: map[string]interface{}{
+				"apiVersion": apiVersion,
+				"kind":       kind,
+			},
+		}
 	}
-}
 
-func TestSort(t *testing.T) {
 	objs := []*runtime.Unstructured{
 		newObj("extensions/v1beta1", "Deployment"),
 		newObj("v1", "ConfigMap"),
@@ -23,7 +27,7 @@ func TestSort(t *testing.T) {
 		newObj("v1", "Service"),
 	}
 
-	SortDepFirst(objs)
+	sort.Sort(DependencyOrder(objs))
 
 	if objs[0].GetKind() != "Namespace" {
 		t.Error("Namespace should be sorted first")
@@ -32,3 +36,35 @@ func TestSort(t *testing.T) {
 		t.Error("Deployment should be sorted after other objects")
 	}
 }
+
+func TestAlphaSort(t *testing.T) {
+	newObj := func(ns, name, kind string) *runtime.Unstructured {
+		o := runtime.Unstructured{}
+		o.SetNamespace(ns)
+		o.SetName(name)
+		o.SetKind(kind)
+		return &o
+	}
+
+	objs := []*runtime.Unstructured{
+		newObj("default", "mysvc", "Deployment"),
+		newObj("", "default", "StorageClass"),
+		newObj("", "default", "ClusterRole"),
+		newObj("default", "mydeploy", "Deployment"),
+		newObj("default", "mysvc", "Secret"),
+	}
+
+	expected := []*runtime.Unstructured{
+		objs[2],
+		objs[1],
+		objs[3],
+		objs[0],
+		objs[4],
+	}
+
+	sort.Sort(AlphabeticalOrder(objs))
+
+	if !reflect.DeepEqual(objs, expected) {
+		t.Errorf("actual != expected: %v != %v", objs, expected)
+	}
+}

vendor/github.com/mattn/go-isatty/LICENSE

+Copyright (c) Yasuhiro MATSUMOTO <mattn.jp@gmail.com>
+
+MIT License (Expat)
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

vendor/github.com/mattn/go-isatty/README.md

+# go-isatty
+
+[![Godoc Reference](https://godoc.org/github.com/mattn/go-isatty?status.svg)](http://godoc.org/github.com/mattn/go-isatty)
+[![Build Status](https://travis-ci.org/mattn/go-isatty.svg?branch=master)](https://travis-ci.org/mattn/go-isatty)
+[![Coverage Status](https://coveralls.io/repos/github/mattn/go-isatty/badge.svg?branch=master)](https://coveralls.io/github/mattn/go-isatty?branch=master)
+[![Go Report Card](https://goreportcard.com/badge/mattn/go-isatty)](https://goreportcard.com/report/mattn/go-isatty)
+
+isatty for golang
+
+## Usage
+
+```go
+package main
+
+import (
+	"fmt"
+	"github.com/mattn/go-isatty"
+	"os"
+)
+
+func main() {
+	if isatty.IsTerminal(os.Stdout.Fd()) {
+		fmt.Println("Is Terminal")
+	} else if isatty.IsCygwinTerminal(os.Stdout.Fd()) {
+		fmt.Println("Is Cygwin/MSYS2 Terminal")
+	} else {
+		fmt.Println("Is Not Terminal")
+	}
+}
+```
+
+## Installation
+
+```
+$ go get github.com/mattn/go-isatty
+```
+
+## License
+
+MIT
+
+## Author
+
+Yasuhiro Matsumoto (a.k.a mattn)
+
+## Thanks
+
+* k-takata: base idea for IsCygwinTerminal
+
+    https://github.com/k-takata/go-iscygpty

vendor/github.com/mattn/go-isatty/doc.go

+// Package isatty implements interface to isatty
+package isatty

vendor/github.com/mattn/go-isatty/isatty_appengine.go

+// +build appengine
+
+package isatty
+
+// IsTerminal returns true if the file descriptor is terminal which
+// is always false on on appengine classic which is a sandboxed PaaS.
+func IsTerminal(fd uintptr) bool {
+	return false
+}
+
+// IsCygwinTerminal() return true if the file descriptor is a cygwin or msys2
+// terminal. This is also always false on this environment.
+func IsCygwinTerminal(fd uintptr) bool {
+	return false
+}

vendor/github.com/mattn/go-isatty/isatty_bsd.go

+// +build darwin freebsd openbsd netbsd dragonfly
+// +build !appengine
+
+package isatty
+
+import (
+	"syscall"
+	"unsafe"
+)
+
+const ioctlReadTermios = syscall.TIOCGETA
+
+// IsTerminal return true if the file descriptor is terminal.
+func IsTerminal(fd uintptr) bool {
+	var termios syscall.Termios
+	_, _, err := syscall.Syscall6(syscall.SYS_IOCTL, fd, ioctlReadTermios, uintptr(unsafe.Pointer(&termios)), 0, 0, 0)
+	return err == 0
+}

vendor/github.com/mattn/go-isatty/isatty_linux.go

+// +build linux
+// +build !appengine
+
+package isatty
+
+import (
+	"syscall"
+	"unsafe"
+)
+
+const ioctlReadTermios = syscall.TCGETS
+
+// IsTerminal return true if the file descriptor is terminal.
+func IsTerminal(fd uintptr) bool {
+	var termios syscall.Termios
+	_, _, err := syscall.Syscall6(syscall.SYS_IOCTL, fd, ioctlReadTermios, uintptr(unsafe.Pointer(&termios)), 0, 0, 0)
+	return err == 0
+}

vendor/github.com/mattn/go-isatty/isatty_others.go

+// +build !windows
+// +build !appengine
+
+package isatty
+
+// IsCygwinTerminal() return true if the file descriptor is a cygwin or msys2
+// terminal. This is also always false on this environment.
+func IsCygwinTerminal(fd uintptr) bool {
+	return false
+}

vendor/github.com/mattn/go-isatty/isatty_solaris.go

+// +build solaris
+// +build !appengine
+
+package isatty
+
+import (
+	"golang.org/x/sys/unix"
+)
+
+// IsTerminal returns true if the given file descriptor is a terminal.
+// see: http://src.illumos.org/source/xref/illumos-gate/usr/src/lib/libbc/libc/gen/common/isatty.c
+func IsTerminal(fd uintptr) bool {
+	var termio unix.Termio
+	err := unix.IoctlSetTermio(int(fd), unix.TCGETA, &termio)
+	return err == nil
+}

vendor/github.com/mattn/go-isatty/isatty_windows.go

+// +build windows
+// +build !appengine
+
+package isatty
+
+import (
+	"strings"
+	"syscall"
+	"unicode/utf16"
+	"unsafe"
+)
+
+const (
+	fileNameInfo uintptr = 2
+	fileTypePipe         = 3
+)
+
+var (
+	kernel32                         = syscall.NewLazyDLL("kernel32.dll")
+	procGetConsoleMode               = kernel32.NewProc("GetConsoleMode")
+	procGetFileInformationByHandleEx = kernel32.NewProc("GetFileInformationByHandleEx")
+	procGetFileType                  = kernel32.NewProc("GetFileType")
+)
+
+func init() {
+	// Check if GetFileInformationByHandleEx is available.
+	if procGetFileInformationByHandleEx.Find() != nil {
+		procGetFileInformationByHandleEx = nil
+	}
+}
+
+// IsTerminal return true if the file descriptor is terminal.
+func IsTerminal(fd uintptr) bool {
+	var st uint32
+	r, _, e := syscall.Syscall(procGetConsoleMode.Addr(), 2, fd, uintptr(unsafe.Pointer(&st)), 0)
+	return r != 0 && e == 0
+}
+
+// Check pipe name is used for cygwin/msys2 pty.
+// Cygwin/MSYS2 PTY has a name like:
+//   \{cygwin,msys}-XXXXXXXXXXXXXXXX-ptyN-{from,to}-master
+func isCygwinPipeName(name string) bool {
+	token := strings.Split(name, "-")
+	if len(token) < 5 {
+		return false
+	}
+
+	if token[0] != `\msys` && token[0] != `\cygwin` {
+		return false
+	}
+
+	if token[1] == "" {
+		return false
+	}
+
+	if !strings.HasPrefix(token[2], "pty") {
+		return false
+	}
+
+	if token[3] != `from` && token[3] != `to` {
+		return false
+	}
+
+	if token[4] != "master" {
+		return false
+	}
+
+	return true
+}
+
+// IsCygwinTerminal() return true if the file descriptor is a cygwin or msys2
+// terminal.
+func IsCygwinTerminal(fd uintptr) bool {
+	if procGetFileInformationByHandleEx == nil {
+		return false
+	}
+
+	// Cygwin/msys's pty is a pipe.
+	ft, _, e := syscall.Syscall(procGetFileType.Addr(), 1, fd, 0, 0)
+	if ft != fileTypePipe || e != 0 {
+		return false
+	}
+
+	var buf [2 + syscall.MAX_PATH]uint16
+	r, _, e := syscall.Syscall6(procGetFileInformationByHandleEx.Addr(),
+		4, fd, fileNameInfo, uintptr(unsafe.Pointer(&buf)),
+		uintptr(len(buf)*2), 0, 0)
+	if r == 0 || e != 0 {
+		return false
+	}
+
+	l := *(*uint32)(unsafe.Pointer(&buf))
+	return isCygwinPipeName(string(utf16.Decode(buf[2 : 2+l/2])))
+}

vendor/github.com/sergi/go-diff/LICENSE

+Copyright (c) 2012-2016 The go-diff Authors. All rights reserved.
+
+Permission is hereby granted, free of charge, to any person obtaining a
+copy of this software and associated documentation files (the "Software"),
+to deal in the Software without restriction, including without limitation
+the rights to use, copy, modify, merge, publish, distribute, sublicense,
+and/or sell copies of the Software, and to permit persons to whom the
+Software is furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included
+in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+DEALINGS IN THE SOFTWARE.
+

vendor/github.com/sergi/go-diff/diffmatchpatch/diffmatchpatch.go

+// Copyright (c) 2012-2016 The go-diff authors. All rights reserved.
+// https://github.com/sergi/go-diff
+// See the included LICENSE file for license details.
+//
+// go-diff is a Go implementation of Google's Diff, Match, and Patch library
+// Original library is Copyright (c) 2006 Google Inc.
+// http://code.google.com/p/google-diff-match-patch/
+
+// Package diffmatchpatch offers robust algorithms to perform the operations required for synchronizing plain text.
+package diffmatchpatch
+
+import (
+	"time"
+)
+
+// DiffMatchPatch holds the configuration for diff-match-patch operations.
+type DiffMatchPatch struct {
+	// Number of seconds to map a diff before giving up (0 for infinity).
+	DiffTimeout time.Duration
+	// Cost of an empty edit operation in terms of edit characters.
+	DiffEditCost int
+	// How far to search for a match (0 = exact location, 1000+ = broad match). A match this many characters away from the expected location will add 1.0 to the score (0.0 is a perfect match).
+	MatchDistance int
+	// When deleting a large block of text (over ~64 characters), how close do the contents have to be to match the expected contents. (0.0 = perfection, 1.0 = very loose).  Note that MatchThreshold controls how closely the end points of a delete need to match.
+	PatchDeleteThreshold float64
+	// Chunk size for context length.
+	PatchMargin int
+	// The number of bits in an int.
+	MatchMaxBits int
+	// At what point is no match declared (0.0 = perfection, 1.0 = very loose).
+	MatchThreshold float64
+}
+
+// New creates a new DiffMatchPatch object with default parameters.
+func New() *DiffMatchPatch {
+	// Defaults.
+	return &DiffMatchPatch{
+		DiffTimeout:          time.Second,
+		DiffEditCost:         4,
+		MatchThreshold:       0.5,
+		MatchDistance:        1000,
+		PatchDeleteThreshold: 0.5,
+		PatchMargin:          4,
+		MatchMaxBits:         32,
+	}
+}

vendor/github.com/sergi/go-diff/diffmatchpatch/match.go

+// Copyright (c) 2012-2016 The go-diff authors. All rights reserved.
+// https://github.com/sergi/go-diff
+// See the included LICENSE file for license details.
+//
+// go-diff is a Go implementation of Google's Diff, Match, and Patch library
+// Original library is Copyright (c) 2006 Google Inc.
+// http://code.google.com/p/google-diff-match-patch/
+
+package diffmatchpatch
+
+import (
+	"math"
+)
+
+// MatchMain locates the best instance of 'pattern' in 'text' near 'loc'.
+// Returns -1 if no match found.
+func (dmp *DiffMatchPatch) MatchMain(text, pattern string, loc int) int {
+	// Check for null inputs not needed since null can't be passed in C#.
+
+	loc = int(math.Max(0, math.Min(float64(loc), float64(len(text)))))
+	if text == pattern {
+		// Shortcut (potentially not guaranteed by the algorithm)
+		return 0
+	} else if len(text) == 0 {
+		// Nothing to match.
+		return -1
+	} else if loc+len(pattern) <= len(text) && text[loc:loc+len(pattern)] == pattern {
+		// Perfect match at the perfect spot!  (Includes case of null pattern)
+		return loc
+	}
+	// Do a fuzzy compare.
+	return dmp.MatchBitap(text, pattern, loc)
+}
+
+// MatchBitap locates the best instance of 'pattern' in 'text' near 'loc' using the Bitap algorithm.
+// Returns -1 if no match was found.
+func (dmp *DiffMatchPatch) MatchBitap(text, pattern string, loc int) int {
+	// Initialise the alphabet.
+	s := dmp.MatchAlphabet(pattern)
+
+	// Highest score beyond which we give up.
+	scoreThreshold := dmp.MatchThreshold
+	// Is there a nearby exact match? (speedup)
+	bestLoc := indexOf(text, pattern, loc)
+	if bestLoc != -1 {
+		scoreThreshold = math.Min(dmp.matchBitapScore(0, bestLoc, loc,
+			pattern), scoreThreshold)
+		// What about in the other direction? (speedup)
+		bestLoc = lastIndexOf(text, pattern, loc+len(pattern))
+		if bestLoc != -1 {
+			scoreThreshold = math.Min(dmp.matchBitapScore(0, bestLoc, loc,
+				pattern), scoreThreshold)
+		}
+	}
+
+	// Initialise the bit arrays.
+	matchmask := 1 << uint((len(pattern) - 1))
+	bestLoc = -1
+
+	var binMin, binMid int
+	binMax := len(pattern) + len(text)
+	lastRd := []int{}
+	for d := 0; d < len(pattern); d++ {
+		// Scan for the best match; each iteration allows for one more error. Run a binary search to determine how far from 'loc' we can stray at this error level.
+		binMin = 0
+		binMid = binMax
+		for binMin < binMid {
+			if dmp.matchBitapScore(d, loc+binMid, loc, pattern) <= scoreThreshold {
+				binMin = binMid
+			} else {
+				binMax = binMid
+			}
+			binMid = (binMax-binMin)/2 + binMin
+		}
+		// Use the result from this iteration as the maximum for the next.
+		binMax = binMid
+		start := int(math.Max(1, float64(loc-binMid+1)))
+		finish := int(math.Min(float64(loc+binMid), float64(len(text))) + float64(len(pattern)))
+
+		rd := make([]int, finish+2)
+		rd[finish+1] = (1 << uint(d)) - 1
+
+		for j := finish; j >= start; j-- {
+			var charMatch int
+			if len(text) <= j-1 {
+				// Out of range.
+				charMatch = 0
+			} else if _, ok := s[text[j-1]]; !ok {
+				charMatch = 0
+			} else {
+				charMatch = s[text[j-1]]
+			}
+
+			if d == 0 {
+				// First pass: exact match.
+				rd[j] = ((rd[j+1] << 1) | 1) & charMatch
+			} else {
+				// Subsequent passes: fuzzy match.
+				rd[j] = ((rd[j+1]<<1)|1)&charMatch | (((lastRd[j+1] | lastRd[j]) << 1) | 1) | lastRd[j+1]
+			}
+			if (rd[j] & matchmask) != 0 {
+				score := dmp.matchBitapScore(d, j-1, loc, pattern)
+				// This match will almost certainly be better than any existing match.  But check anyway.
+				if score <= scoreThreshold {
+					// Told you so.
+					scoreThreshold = score
+					bestLoc = j - 1
+					if bestLoc > loc {
+						// When passing loc, don't exceed our current distance from loc.
+						start = int(math.Max(1, float64(2*loc-bestLoc)))
+					} else {
+						// Already passed loc, downhill from here on in.
+						break
+					}
+				}
+			}
+		}
+		if dmp.matchBitapScore(d+1, loc, loc, pattern) > scoreThreshold {
+			// No hope for a (better) match at greater error levels.
+			break
+		}
+		lastRd = rd
+	}
+	return bestLoc
+}
+
+// matchBitapScore computes and returns the score for a match with e errors and x location.
+func (dmp *DiffMatchPatch) matchBitapScore(e, x, loc int, pattern string) float64 {
+	accuracy := float64(e) / float64(len(pattern))
+	proximity := math.Abs(float64(loc - x))
+	if dmp.MatchDistance == 0 {
+		// Dodge divide by zero error.
+		if proximity == 0 {
+			return accuracy
+		}
+
+		return 1.0
+	}
+	return accuracy + (proximity / float64(dmp.MatchDistance))
+}
+
+// MatchAlphabet initialises the alphabet for the Bitap algorithm.
+func (dmp *DiffMatchPatch) MatchAlphabet(pattern string) map[byte]int {
+	s := map[byte]int{}
+	charPattern := []byte(pattern)
+	for _, c := range charPattern {
+		_, ok := s[c]
+		if !ok {
+			s[c] = 0
+		}
+	}
+	i := 0
+
+	for _, c := range charPattern {
+		value := s[c] | int(uint(1)<<uint((len(pattern)-i-1)))
+		s[c] = value
+		i++
+	}
+	return s
+}

vendor/github.com/sergi/go-diff/diffmatchpatch/mathutil.go

+// Copyright (c) 2012-2016 The go-diff authors. All rights reserved.
+// https://github.com/sergi/go-diff
+// See the included LICENSE file for license details.
+//
+// go-diff is a Go implementation of Google's Diff, Match, and Patch library
+// Original library is Copyright (c) 2006 Google Inc.
+// http://code.google.com/p/google-diff-match-patch/
+
+package diffmatchpatch
+
+func min(x, y int) int {
+	if x < y {
+		return x
+	}
+	return y
+}
+
+func max(x, y int) int {
+	if x > y {
+		return x
+	}
+	return y
+}

vendor/github.com/sergi/go-diff/diffmatchpatch/patch.go

+// Copyright (c) 2012-2016 The go-diff authors. All rights reserved.
+// https://github.com/sergi/go-diff
+// See the included LICENSE file for license details.
+//
+// go-diff is a Go implementation of Google's Diff, Match, and Patch library
+// Original library is Copyright (c) 2006 Google Inc.
+// http://code.google.com/p/google-diff-match-patch/
+
+package diffmatchpatch
+
+import (
+	"bytes"
+	"errors"
+	"math"
+	"net/url"
+	"regexp"
+	"strconv"
+	"strings"
+)
+
+// Patch represents one patch operation.
+type Patch struct {
+	diffs   []Diff
+	start1  int
+	start2  int
+	length1 int
+	length2 int
+}
+
+// String emulates GNU diff's format.
+// Header: @@ -382,8 +481,9 @@
+// Indicies are printed as 1-based, not 0-based.
+func (p *Patch) String() string {
+	var coords1, coords2 string
+
+	if p.length1 == 0 {
+		coords1 = strconv.Itoa(p.start1) + ",0"
+	} else if p.length1 == 1 {
+		coords1 = strconv.Itoa(p.start1 + 1)
+	} else {
+		coords1 = strconv.Itoa(p.start1+1) + "," + strconv.Itoa(p.length1)
+	}
+
+	if p.length2 == 0 {
+		coords2 = strconv.Itoa(p.start2) + ",0"
+	} else if p.length2 == 1 {
+		coords2 = strconv.Itoa(p.start2 + 1)
+	} else {
+		coords2 = strconv.Itoa(p.start2+1) + "," + strconv.Itoa(p.length2)
+	}
+
+	var text bytes.Buffer
+	_, _ = text.WriteString("@@ -" + coords1 + " +" + coords2 + " @@\n")
+
+	// Escape the body of the patch with %xx notation.
+	for _, aDiff := range p.diffs {
+		switch aDiff.Type {
+		case DiffInsert:
+			_, _ = text.WriteString("+")
+		case DiffDelete:
+			_, _ = text.WriteString("-")
+		case DiffEqual:
+			_, _ = text.WriteString(" ")
+		}
+
+		_, _ = text.WriteString(strings.Replace(url.QueryEscape(aDiff.Text), "+", " ", -1))
+		_, _ = text.WriteString("\n")
+	}
+
+	return unescaper.Replace(text.String())
+}
+
+// PatchAddContext increases the context until it is unique, but doesn't let the pattern expand beyond MatchMaxBits.
+func (dmp *DiffMatchPatch) PatchAddContext(patch Patch, text string) Patch {
+	if len(text) == 0 {
+		return patch
+	}
+
+	pattern := text[patch.start2 : patch.start2+patch.length1]
+	padding := 0
+
+	// Look for the first and last matches of pattern in text.  If two different matches are found, increase the pattern length.
+	for strings.Index(text, pattern) != strings.LastIndex(text, pattern) &&
+		len(pattern) < dmp.MatchMaxBits-2*dmp.PatchMargin {
+		padding += dmp.PatchMargin
+		maxStart := max(0, patch.start2-padding)
+		minEnd := min(len(text), patch.start2+patch.length1+padding)
+		pattern = text[maxStart:minEnd]
+	}
+	// Add one chunk for good luck.
+	padding += dmp.PatchMargin
+
+	// Add the prefix.
+	prefix := text[max(0, patch.start2-padding):patch.start2]
+	if len(prefix) != 0 {
+		patch.diffs = append([]Diff{Diff{DiffEqual, prefix}}, patch.diffs...)
+	}
+	// Add the suffix.
+	suffix := text[patch.start2+patch.length1 : min(len(text), patch.start2+patch.length1+padding)]
+	if len(suffix) != 0 {
+		patch.diffs = append(patch.diffs, Diff{DiffEqual, suffix})
+	}
+
+	// Roll back the start points.
+	patch.start1 -= len(prefix)
+	patch.start2 -= len(prefix)
+	// Extend the lengths.
+	patch.length1 += len(prefix) + len(suffix)
+	patch.length2 += len(prefix) + len(suffix)
+
+	return patch
+}
+
+// PatchMake computes a list of patches.
+func (dmp *DiffMatchPatch) PatchMake(opt ...interface{}) []Patch {
+	if len(opt) == 1 {
+		diffs, _ := opt[0].([]Diff)
+		text1 := dmp.DiffText1(diffs)
+		return dmp.PatchMake(text1, diffs)
+	} else if len(opt) == 2 {
+		text1 := opt[0].(string)
+		switch t := opt[1].(type) {
+		case string:
+			diffs := dmp.DiffMain(text1, t, true)
+			if len(diffs) > 2 {
+				diffs = dmp.DiffCleanupSemantic(diffs)
+				diffs = dmp.DiffCleanupEfficiency(diffs)
+			}
+			return dmp.PatchMake(text1, diffs)
+		case []Diff:
+			return dmp.patchMake2(text1, t)
+		}
+	} else if len(opt) == 3 {
+		return dmp.PatchMake(opt[0], opt[2])
+	}
+	return []Patch{}
+}
+
+// patchMake2 computes a list of patches to turn text1 into text2.
+// text2 is not provided, diffs are the delta between text1 and text2.
+func (dmp *DiffMatchPatch) patchMake2(text1 string, diffs []Diff) []Patch {
+	// Check for null inputs not needed since null can't be passed in C#.
+	patches := []Patch{}
+	if len(diffs) == 0 {
+		return patches // Get rid of the null case.
+	}
+
+	patch := Patch{}
+	charCount1 := 0 // Number of characters into the text1 string.
+	charCount2 := 0 // Number of characters into the text2 string.
+	// Start with text1 (prepatchText) and apply the diffs until we arrive at text2 (postpatchText). We recreate the patches one by one to determine context info.
+	prepatchText := text1
+	postpatchText := text1
+
+	for i, aDiff := range diffs {
+		if len(patch.diffs) == 0 && aDiff.Type != DiffEqual {
+			// A new patch starts here.
+			patch.start1 = charCount1
+			patch.start2 = charCount2
+		}
+
+		switch aDiff.Type {
+		case DiffInsert:
+			patch.diffs = append(patch.diffs, aDiff)
+			patch.length2 += len(aDiff.Text)
+			postpatchText = postpatchText[:charCount2] +
+				aDiff.Text + postpatchText[charCount2:]
+		case DiffDelete:
+			patch.length1 += len(aDiff.Text)
+			patch.diffs = append(patch.diffs, aDiff)
+			postpatchText = postpatchText[:charCount2] + postpatchText[charCount2+len(aDiff.Text):]
+		case DiffEqual:
+			if len(aDiff.Text) <= 2*dmp.PatchMargin &&
+				len(patch.diffs) != 0 && i != len(diffs)-1 {
+				// Small equality inside a patch.
+				patch.diffs = append(patch.diffs, aDiff)
+				patch.length1 += len(aDiff.Text)
+				patch.length2 += len(aDiff.Text)
+			}
+			if len(aDiff.Text) >= 2*dmp.PatchMargin {
+				// Time for a new patch.
+				if len(patch.diffs) != 0 {
+					patch = dmp.PatchAddContext(patch, prepatchText)
+					patches = append(patches, patch)
+					patch = Patch{}
+					// Unlike Unidiff, our patch lists have a rolling context. http://code.google.com/p/google-diff-match-patch/wiki/Unidiff Update prepatch text & pos to reflect the application of the just completed patch.
+					prepatchText = postpatchText
+					charCount1 = charCount2
+				}
+			}
+		}
+
+		// Update the current character count.
+		if aDiff.Type != DiffInsert {
+			charCount1 += len(aDiff.Text)
+		}
+		if aDiff.Type != DiffDelete {
+			charCount2 += len(aDiff.Text)
+		}
+	}
+
+	// Pick up the leftover patch if not empty.
+	if len(patch.diffs) != 0 {
+		patch = dmp.PatchAddContext(patch, prepatchText)
+		patches = append(patches, patch)
+	}
+
+	return patches
+}
+
+// PatchDeepCopy returns an array that is identical to a given an array of patches.
+func (dmp *DiffMatchPatch) PatchDeepCopy(patches []Patch) []Patch {
+	patchesCopy := []Patch{}
+	for _, aPatch := range patches {
+		patchCopy := Patch{}
+		for _, aDiff := range aPatch.diffs {
+			patchCopy.diffs = append(patchCopy.diffs, Diff{
+				aDiff.Type,
+				aDiff.Text,
+			})
+		}
+		patchCopy.start1 = aPatch.start1
+		patchCopy.start2 = aPatch.start2
+		patchCopy.length1 = aPatch.length1
+		patchCopy.length2 = aPatch.length2
+		patchesCopy = append(patchesCopy, patchCopy)
+	}
+	return patchesCopy
+}
+
+// PatchApply merges a set of patches onto the text.  Returns a patched text, as well as an array of true/false values indicating which patches were applied.
+func (dmp *DiffMatchPatch) PatchApply(patches []Patch, text string) (string, []bool) {
+	if len(patches) == 0 {
+		return text, []bool{}
+	}
+
+	// Deep copy the patches so that no changes are made to originals.
+	patches = dmp.PatchDeepCopy(patches)
+
+	nullPadding := dmp.PatchAddPadding(patches)
+	text = nullPadding + text + nullPadding
+	patches = dmp.PatchSplitMax(patches)
+
+	x := 0
+	// delta keeps track of the offset between the expected and actual location of the previous patch.  If there are patches expected at positions 10 and 20, but the first patch was found at 12, delta is 2 and the second patch has an effective expected position of 22.
+	delta := 0
+	results := make([]bool, len(patches))
+	for _, aPatch := range patches {
+		expectedLoc := aPatch.start2 + delta
+		text1 := dmp.DiffText1(aPatch.diffs)
+		var startLoc int
+		endLoc := -1
+		if len(text1) > dmp.MatchMaxBits {
+			// PatchSplitMax will only provide an oversized pattern in the case of a monster delete.
+			startLoc = dmp.MatchMain(text, text1[:dmp.MatchMaxBits], expectedLoc)
+			if startLoc != -1 {
+				endLoc = dmp.MatchMain(text,
+					text1[len(text1)-dmp.MatchMaxBits:], expectedLoc+len(text1)-dmp.MatchMaxBits)
+				if endLoc == -1 || startLoc >= endLoc {
+					// Can't find valid trailing context.  Drop this patch.
+					startLoc = -1
+				}
+			}
+		} else {
+			startLoc = dmp.MatchMain(text, text1, expectedLoc)
+		}
+		if startLoc == -1 {
+			// No match found.  :(
+			results[x] = false
+			// Subtract the delta for this failed patch from subsequent patches.
+			delta -= aPatch.length2 - aPatch.length1
+		} else {
+			// Found a match.  :)
+			results[x] = true
+			delta = startLoc - expectedLoc
+			var text2 string
+			if endLoc == -1 {
+				text2 = text[startLoc:int(math.Min(float64(startLoc+len(text1)), float64(len(text))))]
+			} else {
+				text2 = text[startLoc:int(math.Min(float64(endLoc+dmp.MatchMaxBits), float64(len(text))))]
+			}
+			if text1 == text2 {
+				// Perfect match, just shove the Replacement text in.
+				text = text[:startLoc] + dmp.DiffText2(aPatch.diffs) + text[startLoc+len(text1):]
+			} else {
+				// Imperfect match.  Run a diff to get a framework of equivalent indices.
+				diffs := dmp.DiffMain(text1, text2, false)
+				if len(text1) > dmp.MatchMaxBits && float64(dmp.DiffLevenshtein(diffs))/float64(len(text1)) > dmp.PatchDeleteThreshold {
+					// The end points match, but the content is unacceptably bad.
+					results[x] = false
+				} else {
+					diffs = dmp.DiffCleanupSemanticLossless(diffs)
+					index1 := 0
+					for _, aDiff := range aPatch.diffs {
+						if aDiff.Type != DiffEqual {
+							index2 := dmp.DiffXIndex(diffs, index1)
+							if aDiff.Type == DiffInsert {
+								// Insertion
+								text = text[:startLoc+index2] + aDiff.Text + text[startLoc+index2:]
+							} else if aDiff.Type == DiffDelete {
+								// Deletion
+								startIndex := startLoc + index2
+								text = text[:startIndex] +
+									text[startIndex+dmp.DiffXIndex(diffs, index1+len(aDiff.Text))-index2:]
+							}
+						}
+						if aDiff.Type != DiffDelete {
+							index1 += len(aDiff.Text)
+						}
+					}
+				}
+			}
+		}
+		x++
+	}
+	// Strip the padding off.
+	text = text[len(nullPadding) : len(nullPadding)+(len(text)-2*len(nullPadding))]
+	return text, results
+}
+
+// PatchAddPadding adds some padding on text start and end so that edges can match something.
+// Intended to be called only from within patchApply.
+func (dmp *DiffMatchPatch) PatchAddPadding(patches []Patch) string {
+	paddingLength := dmp.PatchMargin
+	nullPadding := ""
+	for x := 1; x <= paddingLength; x++ {
+		nullPadding += string(x)
+	}
+
+	// Bump all the patches forward.
+	for i := range patches {
+		patches[i].start1 += paddingLength
+		patches[i].start2 += paddingLength
+	}
+
+	// Add some padding on start of first diff.
+	if len(patches[0].diffs) == 0 || patches[0].diffs[0].Type != DiffEqual {
+		// Add nullPadding equality.
+		patches[0].diffs = append([]Diff{Diff{DiffEqual, nullPadding}}, patches[0].diffs...)
+		patches[0].start1 -= paddingLength // Should be 0.
+		patches[0].start2 -= paddingLength // Should be 0.
+		patches[0].length1 += paddingLength
+		patches[0].length2 += paddingLength
+	} else if paddingLength > len(patches[0].diffs[0].Text) {
+		// Grow first equality.
+		extraLength := paddingLength - len(patches[0].diffs[0].Text)
+		patches[0].diffs[0].Text = nullPadding[len(patches[0].diffs[0].Text):] + patches[0].diffs[0].Text
+		patches[0].start1 -= extraLength
+		patches[0].start2 -= extraLength
+		patches[0].length1 += extraLength
+		patches[0].length2 += extraLength
+	}
+
+	// Add some padding on end of last diff.
+	last := len(patches) - 1
+	if len(patches[last].diffs) == 0 || patches[last].diffs[len(patches[last].diffs)-1].Type != DiffEqual {
+		// Add nullPadding equality.
+		patches[last].diffs = append(patches[last].diffs, Diff{DiffEqual, nullPadding})
+		patches[last].length1 += paddingLength
+		patches[last].length2 += paddingLength
+	} else if paddingLength > len(patches[last].diffs[len(patches[last].diffs)-1].Text) {
+		// Grow last equality.
+		lastDiff := patches[last].diffs[len(patches[last].diffs)-1]
+		extraLength := paddingLength - len(lastDiff.Text)
+		patches[last].diffs[len(patches[last].diffs)-1].Text += nullPadding[:extraLength]
+		patches[last].length1 += extraLength
+		patches[last].length2 += extraLength
+	}
+
+	return nullPadding
+}
+
+// PatchSplitMax looks through the patches and breaks up any which are longer than the maximum limit of the match algorithm.
+// Intended to be called only from within patchApply.
+func (dmp *DiffMatchPatch) PatchSplitMax(patches []Patch) []Patch {
+	patchSize := dmp.MatchMaxBits
+	for x := 0; x < len(patches); x++ {
+		if patches[x].length1 <= patchSize {
+			continue
+		}
+		bigpatch := patches[x]
+		// Remove the big old patch.
+		patches = append(patches[:x], patches[x+1:]...)
+		x--
+
+		start1 := bigpatch.start1
+		start2 := bigpatch.start2
+		precontext := ""
+		for len(bigpatch.diffs) != 0 {
+			// Create one of several smaller patches.
+			patch := Patch{}
+			empty := true
+			patch.start1 = start1 - len(precontext)
+			patch.start2 = start2 - len(precontext)
+			if len(precontext) != 0 {
+				patch.length1 = len(precontext)
+				patch.length2 = len(precontext)
+				patch.diffs = append(patch.diffs, Diff{DiffEqual, precontext})
+			}
+			for len(bigpatch.diffs) != 0 && patch.length1 < patchSize-dmp.PatchMargin {
+				diffType := bigpatch.diffs[0].Type
+				diffText := bigpatch.diffs[0].Text
+				if diffType == DiffInsert {
+					// Insertions are harmless.
+					patch.length2 += len(diffText)
+					start2 += len(diffText)
+					patch.diffs = append(patch.diffs, bigpatch.diffs[0])
+					bigpatch.diffs = bigpatch.diffs[1:]
+					empty = false
+				} else if diffType == DiffDelete && len(patch.diffs) == 1 && patch.diffs[0].Type == DiffEqual && len(diffText) > 2*patchSize {
+					// This is a large deletion.  Let it pass in one chunk.
+					patch.length1 += len(diffText)
+					start1 += len(diffText)
+					empty = false
+					patch.diffs = append(patch.diffs, Diff{diffType, diffText})
+					bigpatch.diffs = bigpatch.diffs[1:]
+				} else {
+					// Deletion or equality.  Only take as much as we can stomach.
+					diffText = diffText[:min(len(diffText), patchSize-patch.length1-dmp.PatchMargin)]
+
+					patch.length1 += len(diffText)
+					start1 += len(diffText)
+					if diffType == DiffEqual {
+						patch.length2 += len(diffText)
+						start2 += len(diffText)
+					} else {
+						empty = false
+					}
+					patch.diffs = append(patch.diffs, Diff{diffType, diffText})
+					if diffText == bigpatch.diffs[0].Text {
+						bigpatch.diffs = bigpatch.diffs[1:]
+					} else {
+						bigpatch.diffs[0].Text =
+							bigpatch.diffs[0].Text[len(diffText):]
+					}
+				}
+			}
+			// Compute the head context for the next patch.
+			precontext = dmp.DiffText2(patch.diffs)
+			precontext = precontext[max(0, len(precontext)-dmp.PatchMargin):]
+
+			postcontext := ""
+			// Append the end context for this patch.
+			if len(dmp.DiffText1(bigpatch.diffs)) > dmp.PatchMargin {
+				postcontext = dmp.DiffText1(bigpatch.diffs)[:dmp.PatchMargin]
+			} else {
+				postcontext = dmp.DiffText1(bigpatch.diffs)
+			}
+
+			if len(postcontext) != 0 {
+				patch.length1 += len(postcontext)
+				patch.length2 += len(postcontext)
+				if len(patch.diffs) != 0 && patch.diffs[len(patch.diffs)-1].Type == DiffEqual {
+					patch.diffs[len(patch.diffs)-1].Text += postcontext
+				} else {
+					patch.diffs = append(patch.diffs, Diff{DiffEqual, postcontext})
+				}
+			}
+			if !empty {
+				x++
+				patches = append(patches[:x], append([]Patch{patch}, patches[x:]...)...)
+			}
+		}
+	}
+	return patches
+}
+
+// PatchToText takes a list of patches and returns a textual representation.
+func (dmp *DiffMatchPatch) PatchToText(patches []Patch) string {
+	var text bytes.Buffer
+	for _, aPatch := range patches {
+		_, _ = text.WriteString(aPatch.String())
+	}
+	return text.String()
+}
+
+// PatchFromText parses a textual representation of patches and returns a List of Patch objects.
+func (dmp *DiffMatchPatch) PatchFromText(textline string) ([]Patch, error) {
+	patches := []Patch{}
+	if len(textline) == 0 {
+		return patches, nil
+	}
+	text := strings.Split(textline, "\n")
+	textPointer := 0
+	patchHeader := regexp.MustCompile("^@@ -(\\d+),?(\\d*) \\+(\\d+),?(\\d*) @@$")
+
+	var patch Patch
+	var sign uint8
+	var line string
+	for textPointer < len(text) {
+
+		if !patchHeader.MatchString(text[textPointer]) {
+			return patches, errors.New("Invalid patch string: " + text[textPointer])
+		}
+
+		patch = Patch{}
+		m := patchHeader.FindStringSubmatch(text[textPointer])
+
+		patch.start1, _ = strconv.Atoi(m[1])
+		if len(m[2]) == 0 {
+			patch.start1--
+			patch.length1 = 1
+		} else if m[2] == "0" {
+			patch.length1 = 0
+		} else {
+			patch.start1--
+			patch.length1, _ = strconv.Atoi(m[2])
+		}
+
+		patch.start2, _ = strconv.Atoi(m[3])
+
+		if len(m[4]) == 0 {
+			patch.start2--
+			patch.length2 = 1
+		} else if m[4] == "0" {
+			patch.length2 = 0
+		} else {
+			patch.start2--
+			patch.length2, _ = strconv.Atoi(m[4])
+		}
+		textPointer++
+
+		for textPointer < len(text) {
+			if len(text[textPointer]) > 0 {
+				sign = text[textPointer][0]
+			} else {
+				textPointer++
+				continue
+			}
+
+			line = text[textPointer][1:]
+			line = strings.Replace(line, "+", "%2b", -1)
+			line, _ = url.QueryUnescape(line)
+			if sign == '-' {
+				// Deletion.
+				patch.diffs = append(patch.diffs, Diff{DiffDelete, line})
+			} else if sign == '+' {
+				// Insertion.
+				patch.diffs = append(patch.diffs, Diff{DiffInsert, line})
+			} else if sign == ' ' {
+				// Minor equality.
+				patch.diffs = append(patch.diffs, Diff{DiffEqual, line})
+			} else if sign == '@' {
+				// Start of next patch.
+				break
+			} else {
+				// WTF?
+				return patches, errors.New("Invalid patch mode '" + string(sign) + "' in: " + string(line))
+			}
+			textPointer++
+		}
+
+		patches = append(patches, patch)
+	}
+	return patches, nil
+}