filter: introduce pattern struct

This commit is contained in:
Michael Eischer 2021-09-17 23:01:58 +02:00 committed by Alexander Neumann
parent 13c40d4199
commit 5f145f0c7e
1 changed files with 23 additions and 21 deletions

View File

@ -17,7 +17,9 @@ type patternPart struct {
} }
// Pattern represents a preparsed filter pattern // Pattern represents a preparsed filter pattern
type Pattern []patternPart type Pattern struct {
parts []patternPart
}
func prepareStr(str string) ([]string, error) { func prepareStr(str string) ([]string, error) {
if str == "" { if str == "" {
@ -39,7 +41,7 @@ func preparePattern(pattern string) Pattern {
patterns[i] = patternPart{part, isSimple} patterns[i] = patternPart{part, isSimple}
} }
return patterns return Pattern{patterns}
} }
// Split p into path components. Assuming p has been Cleaned, no component // Split p into path components. Assuming p has been Cleaned, no component
@ -103,7 +105,7 @@ func ChildMatch(pattern, str string) (matched bool, err error) {
} }
func childMatch(patterns Pattern, strs []string) (matched bool, err error) { func childMatch(patterns Pattern, strs []string) (matched bool, err error) {
if patterns[0].pattern != "/" { if patterns.parts[0].pattern != "/" {
// relative pattern can always be nested down // relative pattern can always be nested down
return true, nil return true, nil
} }
@ -116,16 +118,16 @@ func childMatch(patterns Pattern, strs []string) (matched bool, err error) {
// match path against absolute pattern prefix // match path against absolute pattern prefix
l := 0 l := 0
if len(strs) > len(patterns) { if len(strs) > len(patterns.parts) {
l = len(patterns) l = len(patterns.parts)
} else { } else {
l = len(strs) l = len(strs)
} }
return match(patterns[0:l], strs) return match(Pattern{patterns.parts[0:l]}, strs)
} }
func hasDoubleWildcard(list Pattern) (ok bool, pos int) { func hasDoubleWildcard(list Pattern) (ok bool, pos int) {
for i, item := range list { for i, item := range list.parts {
if item.pattern == "" { if item.pattern == "" {
return true, i return true, i
} }
@ -137,19 +139,19 @@ func hasDoubleWildcard(list Pattern) (ok bool, pos int) {
func match(patterns Pattern, strs []string) (matched bool, err error) { func match(patterns Pattern, strs []string) (matched bool, err error) {
if ok, pos := hasDoubleWildcard(patterns); ok { if ok, pos := hasDoubleWildcard(patterns); ok {
// gradually expand '**' into separate wildcards // gradually expand '**' into separate wildcards
newPat := make(Pattern, len(strs)) newPat := make([]patternPart, len(strs))
// copy static prefix once // copy static prefix once
copy(newPat, patterns[:pos]) copy(newPat, patterns.parts[:pos])
for i := 0; i <= len(strs)-len(patterns)+1; i++ { for i := 0; i <= len(strs)-len(patterns.parts)+1; i++ {
// limit to static prefix and already appended '*' // limit to static prefix and already appended '*'
newPat := newPat[:pos+i] newPat := newPat[:pos+i]
// in the first iteration the wildcard expands to nothing // in the first iteration the wildcard expands to nothing
if i > 0 { if i > 0 {
newPat[pos+i-1] = patternPart{"*", false} newPat[pos+i-1] = patternPart{"*", false}
} }
newPat = append(newPat, patterns[pos+1:]...) newPat = append(newPat, patterns.parts[pos+1:]...)
matched, err := match(newPat, strs) matched, err := match(Pattern{newPat}, strs)
if err != nil { if err != nil {
return false, err return false, err
} }
@ -162,20 +164,20 @@ func match(patterns Pattern, strs []string) (matched bool, err error) {
return false, nil return false, nil
} }
if len(patterns) == 0 && len(strs) == 0 { if len(patterns.parts) == 0 && len(strs) == 0 {
return true, nil return true, nil
} }
// an empty pattern never matches a non-empty path // an empty pattern never matches a non-empty path
if len(patterns) == 0 { if len(patterns.parts) == 0 {
return false, nil return false, nil
} }
if len(patterns) <= len(strs) { if len(patterns.parts) <= len(strs) {
minOffset := 0 minOffset := 0
maxOffset := len(strs) - len(patterns) maxOffset := len(strs) - len(patterns.parts)
// special case absolute patterns // special case absolute patterns
if patterns[0].pattern == "/" { if patterns.parts[0].pattern == "/" {
maxOffset = 0 maxOffset = 0
} else if strs[0] == "/" { } else if strs[0] == "/" {
// skip absolute path marker if pattern is not rooted // skip absolute path marker if pattern is not rooted
@ -184,12 +186,12 @@ func match(patterns Pattern, strs []string) (matched bool, err error) {
outer: outer:
for offset := maxOffset; offset >= minOffset; offset-- { for offset := maxOffset; offset >= minOffset; offset-- {
for i := len(patterns) - 1; i >= 0; i-- { for i := len(patterns.parts) - 1; i >= 0; i-- {
var ok bool var ok bool
if patterns[i].isSimple { if patterns.parts[i].isSimple {
ok = patterns[i].pattern == strs[offset+i] ok = patterns.parts[i].pattern == strs[offset+i]
} else { } else {
ok, err = filepath.Match(patterns[i].pattern, strs[offset+i]) ok, err = filepath.Match(patterns.parts[i].pattern, strs[offset+i])
if err != nil { if err != nil {
return false, errors.Wrap(err, "Match") return false, errors.Wrap(err, "Match")
} }