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| 1 // Copyright 2015 The Chromium Authors. All rights reserved. | 1 // Copyright 2015 The Chromium Authors. All rights reserved. |
| 2 // Use of this source code is governed by a BSD-style license that can be | 2 // Use of this source code is governed by a BSD-style license that can be |
| 3 // found in the LICENSE file. | 3 // found in the LICENSE file. |
| 4 | 4 |
| 5 package dscache | 5 package dscache |
| 6 | 6 |
| 7 import ( | 7 import ( |
| 8 ds "github.com/luci/gae/service/datastore" | 8 ds "github.com/luci/gae/service/datastore" |
| 9 "github.com/luci/gae/service/info" | 9 "github.com/luci/gae/service/info" |
| 10 mc "github.com/luci/gae/service/memcache" | 10 mc "github.com/luci/gae/service/memcache" |
| (...skipping 10 matching lines...) Expand all Loading... |
| 21 // shardsForKey is a user-controllable function which calculates the number of | 21 // shardsForKey is a user-controllable function which calculates the number of |
| 22 // shards to use for a certain datastore key. The provided key will always be | 22 // shards to use for a certain datastore key. The provided key will always be |
| 23 // valid and complete. | 23 // valid and complete. |
| 24 // | 24 // |
| 25 // The # of shards returned may be between 1 and 256. Values above this range | 25 // The # of shards returned may be between 1 and 256. Values above this range |
| 26 // will be clamped into that range. A return value of 0 means that NO cache | 26 // will be clamped into that range. A return value of 0 means that NO cache |
| 27 // operations should be done for this key, regardless of the dscache.enable | 27 // operations should be done for this key, regardless of the dscache.enable |
| 28 // setting. | 28 // setting. |
| 29 // | 29 // |
| 30 // If shardsForKey is nil, the value of DefaultShards is used for all keys. | 30 // If shardsForKey is nil, the value of DefaultShards is used for all keys. |
| 31 func FilterRDS(c context.Context, shardsForKey func(ds.Key) int) context.Context
{ | 31 func FilterRDS(c context.Context, shardsForKey func(*ds.Key) int) context.Contex
t { |
| 32 if !IsGloballyEnabled(c) { | 32 if !IsGloballyEnabled(c) { |
| 33 return c | 33 return c |
| 34 } | 34 } |
| 35 | 35 |
| 36 return ds.AddRawFilters(c, func(c context.Context, ds ds.RawInterface) d
s.RawInterface { | 36 return ds.AddRawFilters(c, func(c context.Context, ds ds.RawInterface) d
s.RawInterface { |
| 37 i := info.Get(c) | 37 i := info.Get(c) |
| 38 | 38 |
| 39 sc := &supportContext{ | 39 sc := &supportContext{ |
| 40 i.AppID(), | 40 i.AppID(), |
| 41 i.GetNamespace(), | 41 i.GetNamespace(), |
| 42 c, | 42 c, |
| 43 mc.Get(c), | 43 mc.Get(c), |
| 44 mathrand.Get(c), | 44 mathrand.Get(c), |
| 45 shardsForKey, | 45 shardsForKey, |
| 46 } | 46 } |
| 47 | 47 |
| 48 v := c.Value(dsTxnCacheKey) | 48 v := c.Value(dsTxnCacheKey) |
| 49 if v == nil { | 49 if v == nil { |
| 50 return &dsCache{ds, sc} | 50 return &dsCache{ds, sc} |
| 51 } | 51 } |
| 52 return &dsTxnCache{ds, v.(*dsTxnState), sc} | 52 return &dsTxnCache{ds, v.(*dsTxnState), sc} |
| 53 }) | 53 }) |
| 54 } | 54 } |
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