Xray-core/app/router/weight.go

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package router
import (
"context"
"regexp"
"strconv"
"strings"
"sync"
"github.com/xtls/xray-core/common/errors"
)
type weightScaler func(value, weight float64) float64
var numberFinder = regexp.MustCompile(`\d+(\.\d+)?`)
// NewWeightManager creates a new WeightManager with settings
func NewWeightManager(s []*StrategyWeight, defaultWeight float64, scaler weightScaler) *WeightManager {
return &WeightManager{
settings: s,
cache: make(map[string]float64),
scaler: scaler,
defaultWeight: defaultWeight,
}
}
// WeightManager manages weights for specific settings
type WeightManager struct {
settings []*StrategyWeight
cache map[string]float64
scaler weightScaler
defaultWeight float64
mu sync.Mutex
}
// Get get the weight of specified tag
func (s *WeightManager) Get(tag string) float64 {
s.mu.Lock()
defer s.mu.Unlock()
weight, ok := s.cache[tag]
if ok {
return weight
}
weight = s.findValue(tag)
s.cache[tag] = weight
return weight
}
// Apply applies weight to the value
func (s *WeightManager) Apply(tag string, value float64) float64 {
return s.scaler(value, s.Get(tag))
}
func (s *WeightManager) findValue(tag string) float64 {
for _, w := range s.settings {
matched := s.getMatch(tag, w.Match, w.Regexp)
if matched == "" {
continue
}
if w.Value > 0 {
return float64(w.Value)
}
// auto weight from matched
numStr := numberFinder.FindString(matched)
if numStr == "" {
return s.defaultWeight
}
weight, err := strconv.ParseFloat(numStr, 64)
if err != nil {
errors.LogError(context.Background(), "unexpected error from ParseFloat: ", err)
return s.defaultWeight
}
return weight
}
return s.defaultWeight
}
func (s *WeightManager) getMatch(tag, find string, isRegexp bool) string {
if !isRegexp {
idx := strings.Index(tag, find)
if idx < 0 {
return ""
}
return find
}
r, err := regexp.Compile(find)
if err != nil {
errors.LogError(context.Background(), "invalid regexp: ", find, "err: ", err)
return ""
}
return r.FindString(tag)
}