1 /*
2 * Copyright (c) 2021 Huawei Device Co., Ltd.
3 * Licensed under the Apache License, Version 2.0 (the "License");
4 * you may not use this file except in compliance with the License.
5 * You may obtain a copy of the License at
6 *
7 * http://www.apache.org/licenses/LICENSE-2.0
8 *
9 * Unless required by applicable law or agreed to in writing, software
10 * distributed under the License is distributed on an "AS IS" BASIS,
11 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 * See the License for the specific language governing permissions and
13 * limitations under the License.
14 */
15
16 #define LOG_TAG "KvStoreFlowCtrlManager"
17
18 #include "kvstore_flowctrl_manager.h"
19 #include <cinttypes>
20 #include <sys/time.h>
21
22 namespace OHOS {
23 namespace DistributedKv {
24 const int SECOND_TO_MICROSECOND = 1000;
CurrentTimeMicros()25 uint64_t CurrentTimeMicros()
26 {
27 struct timeval tv = { 0, 0 };
28 gettimeofday(&tv, nullptr);
29 return (tv.tv_sec * SECOND_TO_MICROSECOND + tv.tv_usec / SECOND_TO_MICROSECOND);
30 }
31
KvStoreFlowCtrlManager(const int burstCapacity,const int sustainedCapacity)32 KvStoreFlowCtrlManager::KvStoreFlowCtrlManager(const int burstCapacity, const int sustainedCapacity)
33 {
34 burstTokenBucket_.maxCapacity = burstCapacity;
35 burstTokenBucket_.refreshTimeGap = BURST_REFRESH_TIME;
36 sustainedTokenBucket_.maxCapacity = sustainedCapacity;
37 sustainedTokenBucket_.refreshTimeGap = SUSTAINED_REFRESH_TIME;
38 }
39
RefreshTokenBucket(TokenBucket & tokenBucket,uint64_t timestamp)40 void KvStoreFlowCtrlManager::RefreshTokenBucket(TokenBucket &tokenBucket, uint64_t timestamp)
41 {
42 tokenBucket.leftNumInTokenBucket = tokenBucket.maxCapacity;
43 tokenBucket.tokenBucketRefreshTime = timestamp;
44 }
45
IsTokenEnough()46 bool KvStoreFlowCtrlManager::IsTokenEnough()
47 {
48 uint64_t curTime = CurrentTimeMicros();
49 if (IsTokenEnoughSlice(burstTokenBucket_, curTime) && IsTokenEnoughSlice(sustainedTokenBucket_, curTime)) {
50 burstTokenBucket_.lastAccessTime = curTime;
51 burstTokenBucket_.leftNumInTokenBucket--;
52
53 sustainedTokenBucket_.lastAccessTime = curTime;
54 sustainedTokenBucket_.leftNumInTokenBucket--;
55 return true;
56 }
57 return false;
58 }
59
IsTokenEnoughSlice(TokenBucket & tokenBucket,uint64_t timestamp)60 bool KvStoreFlowCtrlManager::IsTokenEnoughSlice(TokenBucket &tokenBucket, uint64_t timestamp)
61 {
62 // the first time to get token will be allowed;
63 // if the gap between this time to get token and the least time to fill the bucket
64 // to the full is larger than 10ms, this operation will be allowed;
65 if (tokenBucket.tokenBucketRefreshTime == 0 ||
66 timestamp - tokenBucket.tokenBucketRefreshTime > tokenBucket.refreshTimeGap) {
67 RefreshTokenBucket(tokenBucket, timestamp);
68 return true;
69 } else {
70 return tokenBucket.leftNumInTokenBucket >= 1;
71 }
72 }
73 } // namespace DistributedKv
74 } // namespace OHOS
75