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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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