restic/filter/filter.go

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2015-07-13 20:05:21 +00:00
package filter
import (
"errors"
"path/filepath"
"strings"
)
// ErrBadString is returned when Match is called with the empty string as the
// second argument.
var ErrBadString = errors.New("filter.Match: string is empty")
// Match returns true if str matches the pattern. When the pattern is
// malformed, filepath.ErrBadPattern is returned. The empty pattern matches
// everything, when str is the empty string ErrBadString is returned.
//
// Pattern can be a combination of patterns suitable for filepath.Match, joined
// by filepath.Separator.
func Match(pattern, str string) (matched bool, err error) {
if pattern == "" {
return true, nil
}
if str == "" {
return false, ErrBadString
}
patterns := strings.Split(pattern, string(filepath.Separator))
strs := strings.Split(str, string(filepath.Separator))
return match(patterns, strs)
}
func match(patterns, strs []string) (matched bool, err error) {
if len(patterns) == 0 && len(strs) == 0 {
return true, nil
}
if len(patterns) <= len(strs) {
outer:
for offset := len(strs) - len(patterns); offset >= 0; offset-- {
for i := len(patterns) - 1; i >= 0; i-- {
ok, err := filepath.Match(patterns[i], strs[offset+i])
if err != nil {
return false, err
}
if !ok {
continue outer
}
}
return true, nil
}
}
return false, nil
}
// MatchList returns true if str matches one of the patterns.
func MatchList(patterns []string, str string) (matched bool, err error) {
for _, pat := range patterns {
matched, err = Match(pat, str)
if err != nil {
return false, err
}
if matched {
return true, nil
}
}
return false, nil
}
// matchList returns true if str matches one of the patterns.
func matchList(patterns [][]string, str []string) (matched bool, err error) {
for _, pat := range patterns {
matched, err = match(pat, str)
if err != nil {
return false, err
}
if matched {
return true, nil
}
}
return false, nil
}
// Filter contains include and exclude patterns. If both lists of patterns are
// empty, all files are accepted.
type Filter struct {
include, exclude [][]string
}
// New returns a new filter with the given include/exclude lists of patterns.
func New(include, exclude []string) *Filter {
f := &Filter{}
for _, pat := range include {
f.include = append(f.include, strings.Split(pat, string(filepath.Separator)))
}
for _, pat := range exclude {
f.exclude = append(f.exclude, strings.Split(pat, string(filepath.Separator)))
}
return f
}
// Match tests a filename against the filter. If include and exclude patterns
// are both empty, true is returned.
//
// If only include patterns and no exclude patterns are configured, true is
// returned iff name matches one of the include patterns.
//
// If only exclude patterns and no include patterns are configured, true is
// returned iff name does not match all of the exclude patterns.
func (f Filter) Match(name string) (matched bool, err error) {
if name == "" {
return false, ErrBadString
}
if len(f.include) == 0 && len(f.exclude) == 0 {
return true, nil
}
names := strings.Split(name, string(filepath.Separator))
if len(f.exclude) == 0 {
return matchList(f.include, names)
}
if len(f.include) == 0 {
match, err := matchList(f.exclude, names)
return !match, err
}
excluded, err := matchList(f.exclude, names)
if err != nil {
return false, err
}
if !excluded {
return true, nil
}
return matchList(f.include, names)
}