// FilterRDS installs a transaction buffer datastore filter in the context.
func FilterRDS(c context.Context) context.Context {
// TODO(riannucci): allow the specification of the set of roots to limit this
// transaction to, transitively.
return ds.AddRawFilters(c, func(c context.Context, rds ds.RawInterface) ds.RawInterface {
if par, _ := c.Value(dsTxnBufParent).(*txnBufState); par != nil {
haveLock, _ := c.Value(dsTxnBufHaveLock).(bool)
return &dsTxnBuf{c, par, haveLock}
}
return &dsBuf{rds}
})
}
// AlwaysFilterRDS installs a caching RawDatastore filter in the context.
//
// Unlike FilterRDS it doesn't check GlobalConfig via IsGloballyEnabled call,
// assuming caller already knows whether filter should be applied or not.
func AlwaysFilterRDS(c context.Context, shardsForKey func(*ds.Key) int) context.Context {
return ds.AddRawFilters(c, func(c context.Context, ds ds.RawInterface) ds.RawInterface {
i := info.Get(c)
sc := &supportContext{
i.AppID(),
i.GetNamespace(),
c,
mc.Get(c),
mathrand.Get(c),
shardsForKey,
}
v := c.Value(dsTxnCacheKey)
if v == nil {
return &dsCache{ds, sc}
}
return &dsTxnCache{ds, v.(*dsTxnState), sc}
})
}
// FilterRDS installs a counter datastore filter in the context.
func FilterRDS(c context.Context) (context.Context, *DSCounter) {
state := &DSCounter{}
return ds.AddRawFilters(c, func(ic context.Context, ds ds.RawInterface) ds.RawInterface {
return &dsCounter{state, ds}
}), state
}
// FilterRDS installs a featureBreaker datastore filter in the context.
func FilterRDS(c context.Context, defaultError error) (context.Context, FeatureBreaker) {
state := newState(defaultError)
return ds.AddRawFilters(c, func(ic context.Context, RawDatastore ds.RawInterface) ds.RawInterface {
return &dsState{state, RawDatastore}
}), state
}