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| 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 |
| 3 // found in the LICENSE file. |
| 4 |
| 5 #include "net/base/backoff_entry_serializer.h" |
| 6 |
| 7 #include "base/strings/string_number_conversions.h" |
| 8 #include "base/time/tick_clock.h" |
| 9 #include "base/values.h" |
| 10 #include "net/base/backoff_entry.h" |
| 11 |
| 12 namespace { |
| 13 // Increment this number when changing the serialization format, to avoid old |
| 14 // serialized values loaded from disk etc being misinterpreted. |
| 15 const int kSerializationFormatVersion = 1; |
| 16 } // namespace |
| 17 |
| 18 namespace net { |
| 19 |
| 20 scoped_ptr<base::Value> BackoffEntrySerializer::SerializeToValue( |
| 21 const BackoffEntry& entry, base::Time time_now) { |
| 22 scoped_ptr<base::ListValue> serialized(new base::ListValue()); |
| 23 serialized->AppendInteger(kSerializationFormatVersion); |
| 24 |
| 25 serialized->AppendInteger(entry.failure_count()); |
| 26 |
| 27 // Can't use entry.GetTimeUntilRelease as it doesn't allow negative deltas. |
| 28 base::TimeDelta backoff_duration = |
| 29 entry.GetReleaseTime() - entry.tick_clock()->NowTicks(); |
| 30 // Redundantly stores both the remaining time delta and the absolute time. |
| 31 // The delta is used to work around some cases where wall clock time changes. |
| 32 serialized->AppendDouble(backoff_duration.InSecondsF()); |
| 33 base::Time absolute_release_time = backoff_duration + time_now; |
| 34 serialized->AppendString( |
| 35 base::Int64ToString(absolute_release_time.ToInternalValue())); |
| 36 |
| 37 return serialized.Pass(); |
| 38 } |
| 39 |
| 40 scoped_ptr<BackoffEntry> BackoffEntrySerializer::DeserializeFromValue( |
| 41 const base::Value& serialized, const BackoffEntry::Policy* policy, |
| 42 base::TickClock* tick_clock, base::Time time_now) { |
| 43 const base::ListValue* serialized_list = nullptr; |
| 44 if (!serialized.GetAsList(&serialized_list)) |
| 45 return nullptr; |
| 46 if (serialized_list->GetSize() != 4) |
| 47 return nullptr; |
| 48 int version_number; |
| 49 if (!serialized_list->GetInteger(0, &version_number) || |
| 50 version_number != kSerializationFormatVersion) { |
| 51 return nullptr; |
| 52 } |
| 53 |
| 54 int failure_count; |
| 55 if (!serialized_list->GetInteger(1, &failure_count) || failure_count < 0) |
| 56 return nullptr; |
| 57 double original_backoff_duration_double; |
| 58 if (!serialized_list->GetDouble(2, &original_backoff_duration_double)) |
| 59 return nullptr; |
| 60 std::string absolute_release_time_string; |
| 61 if (!serialized_list->GetString(3, &absolute_release_time_string)) |
| 62 return nullptr; |
| 63 int64 absolute_release_time_us; |
| 64 if (!base::StringToInt64(absolute_release_time_string, |
| 65 &absolute_release_time_us) || |
| 66 absolute_release_time_us < 0) { |
| 67 return nullptr; |
| 68 } |
| 69 |
| 70 scoped_ptr<BackoffEntry> entry(new BackoffEntry(policy, tick_clock)); |
| 71 |
| 72 for (int n = 0; n < failure_count; n++) |
| 73 entry->InformOfRequest(false); |
| 74 |
| 75 base::TimeDelta original_backoff_duration = |
| 76 base::TimeDelta::FromSecondsD(original_backoff_duration_double); |
| 77 base::Time absolute_release_time = |
| 78 base::Time::FromInternalValue(absolute_release_time_us); |
| 79 base::TimeDelta backoff_duration = absolute_release_time - time_now; |
| 80 // In cases where the system wall clock is rewound, use the redundant |
| 81 // original_backoff_duration to ensure the backoff duration isn't longer |
| 82 // than it was before serializing (note that it's not possible to protect |
| 83 // against the clock being wound forward). |
| 84 if (backoff_duration > original_backoff_duration) |
| 85 backoff_duration = original_backoff_duration; |
| 86 entry->SetCustomReleaseTime( |
| 87 entry->BackoffDurationToReleaseTime(backoff_duration)); |
| 88 |
| 89 return entry; |
| 90 } |
| 91 |
| 92 } // namespace net |
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