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|
package main
import (
"path"
"strings"
)
const (
Cadd = iota
Cdel
Cmod
Cmove
Cskip
)
const (
Fkind = 1 << iota
Fmode
Ftime
Fdata
Flink
)
type Change struct {
kind int
e1, e2 *Entry
fields int
path string
from string
}
type DiffEntFunc func(e1, e2 *Entry) (int, bool)
type Walker interface {
Here() *Entry
Dive() ([]Walker, error)
Path() string
}
func changes(w Walker, mk func(w Walker) Change, ch *[]Change) error {
ent := w.Here()
if ent == nil {
panic("unexpected nil entry")
}
*ch = append(*ch, mk(w))
ws, err := w.Dive()
if err != nil {
return err
}
for _, w := range ws {
err := changes(w, mk, ch)
if err != nil {
return err
}
}
return nil
}
func Diff(w1, w2 Walker, diffent DiffEntFunc, deep bool) ([]Change, error) {
type Wp struct{ w1, w2 Walker }
mkdel := func(w Walker) Change {
return Change{kind: Cdel, e1: w.Here(), path: w.Path()}
}
mkadd := func(w Walker) Change {
return Change{kind: Cadd, e2: w.Here(), path: w.Path()}
}
var chg []Change
stk := make([]Wp, 0, 32)
stk = append(stk, Wp{w1, w2})
for len(stk) > 0 {
wp := stk[len(stk)-1]
stk = stk[:len(stk)-1]
ws1, err := wp.w1.Dive()
if err != nil {
return chg, err
}
ws2, err := wp.w2.Dive()
if err != nil {
return chg, err
}
i1, i2 := 0, 0
for {
var e1, e2 *Entry
if i1 < len(ws1) {
e1 = ws1[i1].Here()
}
if i2 < len(ws2) {
e2 = ws2[i2].Here()
}
if e1 == nil && e2 == nil {
break
}
if e1 == nil || (e2 != nil && e2.Name < e1.Name) {
if deep {
err := changes(ws2[i2], mkadd, &chg)
if err != nil {
return chg, err
}
} else {
chg = append(chg, mkadd(ws2[i2]))
}
i2++
continue
}
if e2 == nil || (e1 != nil && e1.Name < e2.Name) {
if deep {
err := changes(ws1[i1], mkdel, &chg)
if err != nil {
return chg, err
}
} else {
chg = append(chg, mkdel(ws1[i1]))
}
i1++
continue
}
flds, skip := diffent(e1, e2)
if !skip {
stk = append(stk, Wp{ws1[i1], ws2[i2]})
}
if flds != 0 {
path := ws1[i1].Path()
c := Change{Cmod, e1, e2, flds, path, ""}
chg = append(chg, c)
}
i1++
i2++
}
}
return chg, nil
}
func simpleDiff(e1, e2 *Entry) (flds int, skip bool) {
if e1.Kind != e2.Kind {
return Fkind, false
}
skip = false
switch e1.Kind {
case Ereg:
if e1.Mode != e2.Mode {
flds |= Fmode
}
if e1.Msec != e2.Msec {
flds |= Ftime
}
if e1.Size != e2.Size {
flds |= Fdata
}
if e1.Addr.Ok() && e2.Addr.Ok() {
if !AddrEqual(e1.Addr, e2.Addr) {
flds |= Fdata
}
} else if e1.Xxh != 0 && e2.Xxh != 0 {
if e1.Xxh != e2.Xxh {
flds |= Fdata
}
}
case Elnk:
if e1.Dest != e2.Dest {
flds |= Flink
}
case Edir:
if e1.Mode != e2.Mode {
flds |= Fmode
}
if e1.Addr.Ok() {
skip = AddrEqual(e1.Addr, e2.Addr)
}
}
return flds, skip
}
/* strings form some kind of dummy walker */
type DummyWalker string
func (w DummyWalker) Path() string {
return string(w)
}
func (w DummyWalker) Here() *Entry {
return nil
}
func (w DummyWalker) Dive() ([]Walker, error) {
return nil, nil
}
/* Unlike path.Split, this will split on the first '/';
* leading '/' are removed */
func PopDir(p string) (string, string) {
p = StripLeadingSlashes(p)
i := strings.Index(p, "/")
if i == -1 {
return p, ""
}
return p[:i], p[i+1:]
}
/* Follows the path p in the walker w; if at some point
* the walker cannot be moved along the path, a dummy
* walker is returned with no errors */
func WalkTo(w Walker, p string) (Walker, error) {
dir := path.Clean(p)
for {
if dir == "/" || dir == "." || dir == "" {
return w, nil
}
lhs, rhs := PopDir(dir)
ws, err := w.Dive()
if err != nil {
return nil, err
}
var i int
for i = 0; i < len(ws); i++ {
if ws[i].Here().Name == lhs {
break
}
}
if i == len(ws) {
return DummyWalker(p), nil
}
w = ws[i]
dir = rhs
}
}
|
