mirror of https://github.com/stashapp/stash.git
43 lines
1.0 KiB
Go
43 lines
1.0 KiB
Go
package sqlite
|
|
|
|
import (
|
|
"regexp"
|
|
|
|
lru "github.com/hashicorp/golang-lru"
|
|
)
|
|
|
|
// size of the regex LRU cache in elements.
|
|
// A small number number was chosen because it's most likely use is for a
|
|
// single query - this function gets called for every row in the (filtered)
|
|
// results. It's likely to only need no more than 1 or 2 in any given query.
|
|
// After that point, it's just sitting in the cache and is unlikely to be used
|
|
// again.
|
|
const regexCacheSize = 10
|
|
|
|
var regexCache *lru.Cache
|
|
|
|
func init() {
|
|
regexCache, _ = lru.New(regexCacheSize)
|
|
}
|
|
|
|
// regexFn is registered as an SQLite function as "regexp"
|
|
// It uses an LRU cache to cache recent regex patterns to reduce CPU load over
|
|
// identical patterns.
|
|
func regexFn(re, s string) (bool, error) {
|
|
entry, ok := regexCache.Get(re)
|
|
var compiled *regexp.Regexp
|
|
|
|
if !ok {
|
|
var err error
|
|
compiled, err = regexp.Compile(re)
|
|
if err != nil {
|
|
return false, err
|
|
}
|
|
regexCache.Add(re, compiled)
|
|
} else {
|
|
compiled = entry.(*regexp.Regexp)
|
|
}
|
|
|
|
return compiled.MatchString(s), nil
|
|
}
|