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| 1 // Copyright (c) 2006-2008 The Chromium Authors. All rights reserved. | |
| 2 // Use of this source code is governed by a BSD-style license that can be | |
| 3 // found in the LICENSE file. | |
| 4 | |
| 5 #include "chrome/browser/url_fetcher_protect.h" | |
| 6 | |
| 7 // URLFetcherProtectEntry ---------------------------------------------------- | |
| 8 | |
| 9 using base::TimeDelta; | |
| 10 using base::TimeTicks; | |
| 11 | |
| 12 // Default parameters. Time is in milliseconds. | |
| 13 // static | |
| 14 const int URLFetcherProtectEntry::kDefaultSlidingWindowPeriod = 2000; | |
| 15 | |
| 16 const int URLFetcherProtectEntry::kDefaultMaxSendThreshold = 20; | |
| 17 const int URLFetcherProtectEntry::kDefaultMaxRetries = 0; | |
| 18 | |
| 19 const int URLFetcherProtectEntry::kDefaultInitialTimeout = 100; | |
| 20 const double URLFetcherProtectEntry::kDefaultMultiplier = 2.0; | |
| 21 const int URLFetcherProtectEntry::kDefaultConstantFactor = 100; | |
| 22 const int URLFetcherProtectEntry::kDefaultMaximumTimeout = 60000; | |
| 23 | |
| 24 | |
| 25 URLFetcherProtectEntry::URLFetcherProtectEntry() | |
| 26 : sliding_window_period_(kDefaultSlidingWindowPeriod), | |
| 27 max_send_threshold_(kDefaultMaxSendThreshold), | |
| 28 max_retries_(kDefaultMaxRetries), | |
| 29 initial_timeout_(kDefaultInitialTimeout), | |
| 30 multiplier_(kDefaultMultiplier), | |
| 31 constant_factor_(kDefaultConstantFactor), | |
| 32 maximum_timeout_(kDefaultMaximumTimeout) { | |
| 33 ResetBackoff(); | |
| 34 } | |
| 35 | |
| 36 URLFetcherProtectEntry::URLFetcherProtectEntry(int sliding_window_period, | |
| 37 int max_send_threshold, | |
| 38 int max_retries, | |
| 39 int initial_timeout, | |
| 40 double multiplier, | |
| 41 int constant_factor, | |
| 42 int maximum_timeout) | |
| 43 : sliding_window_period_(sliding_window_period), | |
| 44 max_send_threshold_(max_send_threshold), | |
| 45 max_retries_(max_retries), | |
| 46 initial_timeout_(initial_timeout), | |
| 47 multiplier_(multiplier), | |
| 48 constant_factor_(constant_factor), | |
| 49 maximum_timeout_(maximum_timeout) { | |
| 50 ResetBackoff(); | |
| 51 } | |
| 52 | |
| 53 int URLFetcherProtectEntry::UpdateBackoff(EventType event_type) { | |
| 54 // request may be sent in different threads | |
| 55 AutoLock lock(lock_); | |
| 56 | |
| 57 TimeDelta t; | |
| 58 switch (event_type) { | |
| 59 case SEND: | |
| 60 t = AntiOverload(); | |
| 61 break; | |
| 62 case SUCCESS: | |
| 63 t = ResetBackoff(); | |
| 64 break; | |
| 65 case FAILURE: | |
| 66 t = IncreaseBackoff(); | |
| 67 break; | |
| 68 default: | |
| 69 NOTREACHED(); | |
| 70 } | |
| 71 | |
| 72 int wait = static_cast<int>(t.InMilliseconds()); | |
| 73 DCHECK(wait >= 0); | |
| 74 return wait; | |
| 75 } | |
| 76 | |
| 77 TimeDelta URLFetcherProtectEntry::AntiOverload() { | |
| 78 TimeDelta sw = TimeDelta::FromMilliseconds(sliding_window_period_); | |
| 79 TimeTicks now = TimeTicks::Now(); | |
| 80 // Estimate when the next request will be sent. | |
| 81 release_time_ = now; | |
| 82 if (send_log_.size() > 0) { | |
| 83 release_time_ = std::max(release_time_, send_log_.back()); | |
| 84 } | |
| 85 // Checks if there are too many send events in recent time. | |
| 86 if (send_log_.size() >= static_cast<unsigned>(max_send_threshold_)) { | |
| 87 release_time_ = std::max(release_time_, send_log_.front() + sw); | |
| 88 } | |
| 89 // Logs the new send event. | |
| 90 send_log_.push(release_time_); | |
| 91 // Drops the out-of-date events in the event list. | |
| 92 while (!send_log_.empty() && | |
| 93 (send_log_.front() + sw <= send_log_.back())) { | |
| 94 send_log_.pop(); | |
| 95 } | |
| 96 return release_time_ - now; | |
| 97 } | |
| 98 | |
| 99 TimeDelta URLFetcherProtectEntry::ResetBackoff() { | |
| 100 timeout_period_ = initial_timeout_; | |
| 101 release_time_ = TimeTicks::Now(); | |
| 102 return TimeDelta::FromMilliseconds(0); | |
| 103 } | |
| 104 | |
| 105 TimeDelta URLFetcherProtectEntry::IncreaseBackoff() { | |
| 106 TimeTicks now = TimeTicks::Now(); | |
| 107 | |
| 108 release_time_ = std::max(release_time_, now) + | |
| 109 TimeDelta::FromMilliseconds(timeout_period_); | |
| 110 | |
| 111 // Calculates the new backoff time. | |
| 112 timeout_period_ = static_cast<int> | |
| 113 (multiplier_ * timeout_period_ + constant_factor_); | |
| 114 if (maximum_timeout_ && timeout_period_ > maximum_timeout_) | |
| 115 timeout_period_ = maximum_timeout_; | |
| 116 | |
| 117 return release_time_ - now; | |
| 118 } | |
| 119 | |
| 120 // URLFetcherProtectManager -------------------------------------------------- | |
| 121 | |
| 122 // static | |
| 123 scoped_ptr<URLFetcherProtectManager> URLFetcherProtectManager::protect_manager_; | |
| 124 Lock URLFetcherProtectManager::lock_; | |
| 125 | |
| 126 URLFetcherProtectManager::~URLFetcherProtectManager() { | |
| 127 // Deletes all entries | |
| 128 ProtectService::iterator i; | |
| 129 for (i = services_.begin(); i != services_.end(); ++i) { | |
| 130 if (i->second) | |
| 131 delete i->second; | |
| 132 } | |
| 133 } | |
| 134 | |
| 135 // static | |
| 136 URLFetcherProtectManager* URLFetcherProtectManager::GetInstance() { | |
| 137 AutoLock lock(lock_); | |
| 138 | |
| 139 if (protect_manager_.get() == NULL) { | |
| 140 protect_manager_.reset(new URLFetcherProtectManager()); | |
| 141 } | |
| 142 return protect_manager_.get(); | |
| 143 } | |
| 144 | |
| 145 URLFetcherProtectEntry* URLFetcherProtectManager::Register(std::string id) { | |
| 146 AutoLock lock(lock_); | |
| 147 | |
| 148 ProtectService::iterator i = services_.find(id); | |
| 149 | |
| 150 if (i != services_.end()) { | |
| 151 // The entry exists. | |
| 152 return i->second; | |
| 153 } | |
| 154 | |
| 155 // Creates a new entry. | |
| 156 URLFetcherProtectEntry* entry = new URLFetcherProtectEntry(); | |
| 157 services_[id] = entry; | |
| 158 return entry; | |
| 159 } | |
| 160 | |
| 161 URLFetcherProtectEntry* URLFetcherProtectManager::Register( | |
| 162 std::string id, URLFetcherProtectEntry* entry) { | |
| 163 AutoLock lock(lock_); | |
| 164 | |
| 165 ProtectService::iterator i = services_.find(id); | |
| 166 if (i != services_.end()) { | |
| 167 // The entry exists. | |
| 168 delete i->second; | |
| 169 } | |
| 170 | |
| 171 services_[id] = entry; | |
| 172 return entry; | |
| 173 } | |
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