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Replace strings with byte slices for filters #23

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merged 3 commits into from
Mar 28, 2017
Merged

Replace strings with byte slices for filters #23

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1b39bcf
Replace strings with byte slices for filters
Mar 23, 2017
803b9e3
Merge branch 'master' into r/replace-strings-with-byte-slices
Mar 24, 2017
5a8262c
Remove matchedValue struct and add note about UTF8 support
Mar 28, 2017
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116 changes: 61 additions & 55 deletions filters/filter.go
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Original file line number Diff line number Diff line change
Expand Up @@ -24,7 +24,6 @@ import (
"bytes"
"errors"
"fmt"
"strings"
)

var (
Expand Down Expand Up @@ -60,21 +59,24 @@ const (
multiRangeStartChar = '{'
multiRangeEndChar = '}'
invalidNestedChars = "?[{"
multiRangeSplit = ","
)

var (
multiRangeSplit = []byte(",")
)

// Filter matches a string against certain conditions
type Filter interface {
fmt.Stringer

// Matches returns true if the conditions are met
Matches(val string) bool
Matches(val []byte) bool
}

// NewFilter supports startsWith, endsWith, contains and a single wildcard
// along with negation and glob matching support
// TODO(martinm): Provide more detailed error messages
func NewFilter(pattern string) (Filter, error) {
func NewFilter(pattern []byte) (Filter, error) {
if len(pattern) == 0 {
return newEqualityFilter(pattern), nil
}
Expand All @@ -98,8 +100,10 @@ func NewFilter(pattern string) (Filter, error) {

// newWildcardFilter creates a filter that segments the pattern based
// on wildcards, creating a rangeFilter for each segment
func newWildcardFilter(pattern string) (Filter, error) {
wIdx := strings.IndexRune(pattern, wildcardChar)
func newWildcardFilter(pattern []byte) (Filter, error) {
wIdx := bytes.IndexRune(pattern, wildcardChar)

// TODO(r): use utf8 to take into account size of rune in byte slice

if wIdx == -1 {
// No wildcards
Expand All @@ -116,7 +120,7 @@ func newWildcardFilter(pattern string) (Filter, error) {
return newRangeFilter(pattern[:len(pattern)-1], false, start)
}

secondWIdx := strings.IndexRune(pattern[wIdx+1:], wildcardChar)
secondWIdx := bytes.IndexRune(pattern[wIdx+1:], wildcardChar)
if secondWIdx == -1 {
if wIdx == 0 {
// Single wildcard at start
Expand Down Expand Up @@ -147,7 +151,7 @@ func newWildcardFilter(pattern string) (Filter, error) {

// newRangeFilter creates a filter that checks for ranges (? or [] or {}) and segments
// the pattern into a multiple chain filters based on ranges found
func newRangeFilter(pattern string, backwards bool, seg chainSegment) (Filter, error) {
func newRangeFilter(pattern []byte, backwards bool, seg chainSegment) (Filter, error) {
var filters []chainFilter
eqIdx := -1
for i := 0; i < len(pattern); i++ {
Expand All @@ -159,7 +163,7 @@ func newRangeFilter(pattern string, backwards bool, seg chainSegment) (Filter, e
eqIdx = -1
}

endIdx := strings.IndexRune(pattern[i+1:], singleRangeEndChar)
endIdx := bytes.IndexRune(pattern[i+1:], singleRangeEndChar)
if endIdx == -1 {
return nil, errInvalidFilterPattern
}
Expand All @@ -179,7 +183,7 @@ func newRangeFilter(pattern string, backwards bool, seg chainSegment) (Filter, e
eqIdx = -1
}

endIdx := strings.IndexRune(pattern[i+1:], multiRangeEndChar)
endIdx := bytes.IndexRune(pattern[i+1:], multiRangeEndChar)
if endIdx == -1 {
return nil, errInvalidFilterPattern
}
Expand Down Expand Up @@ -218,44 +222,44 @@ type allowFilter struct{}

func newAllowFilter() Filter { return allowAllFilter }
func (f allowFilter) String() string { return "All" }
func (f allowFilter) Matches(val string) bool { return true }
func (f allowFilter) Matches(val []byte) bool { return true }

// equalityFilter is a filter that matches exact values
type equalityFilter struct {
pattern string
pattern []byte
}

func newEqualityFilter(pattern string) Filter {
func newEqualityFilter(pattern []byte) Filter {
return &equalityFilter{pattern: pattern}
}

func (f *equalityFilter) String() string {
return "Equals(\"" + f.pattern + "\")"
return "Equals(\"" + string(f.pattern) + "\")"
}

func (f *equalityFilter) Matches(val string) bool {
return f.pattern == val
func (f *equalityFilter) Matches(val []byte) bool {
return bytes.Equal(f.pattern, val)
}

// containsFilter is a filter that performs contains matches
type containsFilter struct {
pattern string
pattern []byte
}

func newContainsFilter(pattern string) (Filter, error) {
if strings.ContainsAny(pattern, invalidNestedChars) {
func newContainsFilter(pattern []byte) (Filter, error) {
if bytes.ContainsAny(pattern, invalidNestedChars) {
return nil, errInvalidFilterPattern
}

return &containsFilter{pattern: pattern}, nil
}

func (f *containsFilter) String() string {
return "Contains(\"" + f.pattern + "\")"
return "Contains(\"" + string(f.pattern) + "\")"
}

func (f *containsFilter) Matches(val string) bool {
return strings.Contains(val, f.pattern)
func (f *containsFilter) Matches(val []byte) bool {
return bytes.Contains(val, f.pattern)
}

// negationFilter is a filter that matches the opposite of the provided filter
Expand All @@ -271,7 +275,7 @@ func (f *negationFilter) String() string {
return "Not(" + f.filter.String() + ")"
}

func (f *negationFilter) Matches(val string) bool {
func (f *negationFilter) Matches(val []byte) bool {
return !f.filter.Matches(val)
}

Expand Down Expand Up @@ -300,7 +304,7 @@ func (f *multiFilter) String() string {
return buf.String()
}

func (f *multiFilter) Matches(val string) bool {
func (f *multiFilter) Matches(val []byte) bool {
if len(f.filters) == 0 {
return true
}
Expand All @@ -324,34 +328,34 @@ func (f *multiFilter) Matches(val string) bool {
type chainFilter interface {
fmt.Stringer

matches(val string) (string, bool)
matches(val []byte) ([]byte, bool)
}

// equalityChainFilter is a filter that performs equality string matches
// from either the front or back of the string
type equalityChainFilter struct {
pattern string
pattern []byte
backwards bool
}

func newEqualityChainFilter(pattern string, backwards bool) chainFilter {
func newEqualityChainFilter(pattern []byte, backwards bool) chainFilter {
return &equalityChainFilter{pattern: pattern, backwards: backwards}
}

func (f *equalityChainFilter) String() string {
return "Equals(\"" + f.pattern + "\")"
return "Equals(\"" + string(f.pattern) + "\")"
}

func (f *equalityChainFilter) matches(val string) (string, bool) {
if f.backwards && strings.HasSuffix(val, f.pattern) {
func (f *equalityChainFilter) matches(val []byte) ([]byte, bool) {
if f.backwards && bytes.HasSuffix(val, f.pattern) {
return val[:len(val)-len(f.pattern)], true
}

if !f.backwards && strings.HasPrefix(val, f.pattern) {
if !f.backwards && bytes.HasPrefix(val, f.pattern) {
return val[len(f.pattern):], true
}

return "", false
return nil, false
}

// singleAnyCharFilter is a filter that allows any one char
Expand All @@ -369,9 +373,9 @@ func newSingleAnyCharFilter(backwards bool) chainFilter {

func (f *singleAnyCharFilter) String() string { return "AnyChar" }

func (f *singleAnyCharFilter) matches(val string) (string, bool) {
func (f *singleAnyCharFilter) matches(val []byte) ([]byte, bool) {
if len(val) == 0 {
return "", false
return nil, false
}

if f.backwards {
Expand All @@ -383,7 +387,7 @@ func (f *singleAnyCharFilter) matches(val string) (string, bool) {

// newSingleRangeFilter creates a filter that performs range matching
// on a single char
func newSingleRangeFilter(pattern string, backwards bool) (chainFilter, error) {
func newSingleRangeFilter(pattern []byte, backwards bool) (chainFilter, error) {
if len(pattern) == 0 {
return nil, errInvalidFilterPattern
}
Expand All @@ -401,7 +405,7 @@ func newSingleRangeFilter(pattern string, backwards bool) (chainFilter, error) {
return nil, errInvalidFilterPattern
}

patterns := make([]string, 0, len(pattern)%3)
patterns := make([][]byte, 0, len(pattern)%3)
for i := 0; i < len(pattern); i += 3 {
if pattern[i+1] != rangeChar || pattern[i] > pattern[i+2] {
return nil, errInvalidFilterPattern
Expand All @@ -419,7 +423,7 @@ func newSingleRangeFilter(pattern string, backwards bool) (chainFilter, error) {
// singleRangeFilter is a filter that performs a single character match against
// a range of chars given in a range format eg. [a-z]
type singleRangeFilter struct {
patterns []string
patterns [][]byte
backwards bool
negate bool
}
Expand All @@ -431,12 +435,14 @@ func (f *singleRangeFilter) String() string {
negateSuffix = ")"
}

return negatePrefix + "Range(\"" + strings.Join(f.patterns, " "+string(Disjunction)+" ") + "\")" + negateSuffix
return negatePrefix + "Range(\"" +
string(bytes.Join(f.patterns, []byte(fmt.Sprintf(" %s ", Disjunction)))) +
"\")" + negateSuffix
}

func (f *singleRangeFilter) matches(val string) (string, bool) {
func (f *singleRangeFilter) matches(val []byte) ([]byte, bool) {
if len(val) == 0 {
return "", false
return nil, false
}

match := false
Expand Down Expand Up @@ -464,7 +470,7 @@ func (f *singleRangeFilter) matches(val string) (string, bool) {
// singleCharSetFilter is a filter that performs a single character match against
// a set of chars given explicity eg. [abcdefg]
type singleCharSetFilter struct {
pattern string
pattern []byte
backwards bool
negate bool
}
Expand All @@ -476,12 +482,12 @@ func (f *singleCharSetFilter) String() string {
negateSuffix = ")"
}

return negatePrefix + "Range(\"" + f.pattern + "\")" + negateSuffix
return negatePrefix + "Range(\"" + string(f.pattern) + "\")" + negateSuffix
}

func (f *singleCharSetFilter) matches(val string) (string, bool) {
func (f *singleCharSetFilter) matches(val []byte) ([]byte, bool) {
if len(val) == 0 {
return "", false
return nil, false
}

match := false
Expand Down Expand Up @@ -511,41 +517,41 @@ func (f *singleCharSetFilter) matches(val string) (string, bool) {
// multiCharRangeFilter is a filter that performs matches against multiple sets of chars
// eg. {abc,defg}
type multiCharSequenceFilter struct {
patterns []string
patterns [][]byte
backwards bool
}

func newMultiCharSequenceFilter(patterns string, backwards bool) (chainFilter, error) {
func newMultiCharSequenceFilter(patterns []byte, backwards bool) (chainFilter, error) {
if len(patterns) == 0 {
return nil, errInvalidFilterPattern
}

return &multiCharSequenceFilter{
patterns: strings.Split(patterns, multiRangeSplit),
patterns: bytes.Split(patterns, multiRangeSplit),
backwards: backwards,
}, nil
}

func (f *multiCharSequenceFilter) String() string {
return "Range(\"" + strings.Join(f.patterns, multiRangeSplit) + "\")"
return "Range(\"" + string(bytes.Join(f.patterns, multiRangeSplit)) + "\")"
}

func (f *multiCharSequenceFilter) matches(val string) (string, bool) {
func (f *multiCharSequenceFilter) matches(val []byte) ([]byte, bool) {
if len(val) == 0 {
return "", false
return nil, false
}

for _, pattern := range f.patterns {
if f.backwards && strings.HasSuffix(val, pattern) {
if f.backwards && bytes.HasSuffix(val, pattern) {
return val[:len(val)-len(pattern)], true
}

if !f.backwards && strings.HasPrefix(val, pattern) {
if !f.backwards && bytes.HasPrefix(val, pattern) {
return val[len(pattern):], true
}
}

return "", false
return nil, false
}

// multiChainFilter chains multiple chainFilters together with &&
Expand Down Expand Up @@ -586,7 +592,7 @@ func (f *multiChainFilter) String() string {
return buf.String()
}

func (f *multiChainFilter) Matches(val string) bool {
func (f *multiChainFilter) Matches(val []byte) bool {
if len(f.filters) == 0 {
return true
}
Expand All @@ -609,7 +615,7 @@ func (f *multiChainFilter) Matches(val string) bool {
}
}

if f.seg == middle && val != "" {
if f.seg == middle && len(val) != 0 {
// chain was middle segment and some value was left over at end of chain
return false
}
Expand Down
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