ref: f5ed04bd4a2ba1a62482b381470f04aad98375f5
parent: 7730d683e8b030c64c5f986b8166c8e65b777ab3
author: Bjørn Erik Pedersen <[email protected]>
date: Wed Nov 15 20:23:37 EST 2017
tpl/partials: Fix cache locking To make sure a cached partial is ony executed exactly once. Performance same: ```bash name old time/op new time/op delta TemplateParamsKeysToLower-4 17.2µs ± 0% 16.5µs ± 0% ~ (p=1.000 n=1+1) Partial-4 18.6µs ± 0% 19.4µs ± 0% ~ (p=1.000 n=1+1) PartialCached-4 64.2ns ± 0% 63.7ns ± 0% ~ (p=1.000 n=1+1) name old alloc/op new alloc/op delta TemplateParamsKeysToLower-4 2.66kB ± 0% 2.66kB ± 0% ~ (all equal) Partial-4 1.31kB ± 0% 1.31kB ± 0% ~ (all equal) PartialCached-4 0.00B 0.00B ~ (all equal) name old allocs/op new allocs/op delta TemplateParamsKeysToLower-4 92.0 ± 0% 92.0 ± 0% ~ (all equal) Partial-4 41.0 ± 0% 41.0 ± 0% ~ (all equal) ```
--- a/tpl/partials/partials.go
+++ b/tpl/partials/partials.go
@@ -110,27 +110,30 @@
return ns.getOrCreate(key, name, context)
}
-func (ns *Namespace) getOrCreate(key, name string, context interface{}) (p interface{}, err error) {- var ok bool
+func (ns *Namespace) getOrCreate(key, name string, context interface{}) (interface{}, error) {ns.cachedPartials.RLock()
- p, ok = ns.cachedPartials.p[key]
+ p, ok := ns.cachedPartials.p[key]
ns.cachedPartials.RUnlock()
if ok {- return
+ return p, nil
}
ns.cachedPartials.Lock()
- if p, ok = ns.cachedPartials.p[key]; !ok {- ns.cachedPartials.Unlock()
- p, err = ns.Include(name, context)
+ defer ns.cachedPartials.Unlock()
- ns.cachedPartials.Lock()
- ns.cachedPartials.p[key] = p
+ // Double-check.
+ if p, ok = ns.cachedPartials.p[key]; ok {+ return p, nil
+ }
+ p, err := ns.Include(name, context)
+ if err != nil {+ return nil, err
}
- ns.cachedPartials.Unlock()
- return
+ ns.cachedPartials.p[key] = p
+
+ return p, nil
}