peridot/vendor/github.com/antchfx/xmlquery/cache.go

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2022-07-07 20:11:50 +00:00
package xmlquery
import (
"sync"
"github.com/golang/groupcache/lru"
"github.com/antchfx/xpath"
)
// DisableSelectorCache will disable caching for the query selector if value is true.
var DisableSelectorCache = false
// SelectorCacheMaxEntries allows how many selector object can be caching. Default is 50.
// Will disable caching if SelectorCacheMaxEntries <= 0.
var SelectorCacheMaxEntries = 50
var (
cacheOnce sync.Once
cache *lru.Cache
cacheMutex sync.Mutex
)
func getQuery(expr string) (*xpath.Expr, error) {
if DisableSelectorCache || SelectorCacheMaxEntries <= 0 {
return xpath.Compile(expr)
}
cacheOnce.Do(func() {
cache = lru.New(SelectorCacheMaxEntries)
})
cacheMutex.Lock()
defer cacheMutex.Unlock()
if v, ok := cache.Get(expr); ok {
return v.(*xpath.Expr), nil
}
v, err := xpath.Compile(expr)
if err != nil {
return nil, err
}
cache.Add(expr, v)
return v, nil
}