43 lines
658 B
Go
43 lines
658 B
Go
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package rcache
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import (
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"crypto/md5"
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"regexp"
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"runtime"
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"sync"
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)
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var (
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cores int
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cache map[[16]byte]*regexp.Regexp = map[[16]byte]*regexp.Regexp{}
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lock sync.RWMutex
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)
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func Get(expression string) *regexp.Regexp {
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if cores == 0 {
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cores = runtime.NumCPU()
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}
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key := md5.Sum([]byte(expression))
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if cores > 1 {
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lock.RLock()
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}
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if cache[key] != nil {
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if cores > 1 {
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defer lock.RUnlock()
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}
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return cache[key].Copy()
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}
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if cores > 1 {
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lock.RUnlock()
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}
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if regex, err := regexp.Compile(expression); err == nil {
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if cores > 1 {
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lock.Lock()
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defer lock.Unlock()
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}
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cache[key] = regex
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return cache[key].Copy()
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}
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return nil
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}
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