chrome/browser/sync/retry_verifier.h

   1 // Copyright (c) 2012 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 #ifndef CHROME_BROWSER_SYNC_RETRY_VERIFIER_H_
   6 #define CHROME_BROWSER_SYNC_RETRY_VERIFIER_H_
   7
   8 #include "base/time.h"
   9
  10 // TODO(akalin): Move this to somewhere in sync/ and make
  11 // sync/engine/polling_constants.h private.
  12
  13 namespace syncer {
  14 namespace sessions {
  15 class SyncSessionSnapshot;
  16 }  // namespace sessions
  17 }  // namespace syncer
  18
  19 namespace browser_sync {
  20
  21 // The minimum and maximum wait times for a retry. The actual retry would take
  22 // place somewhere in this range. The algorithm that calculates the retry wait
  23 // time uses rand functions.
  24 struct DelayInfo {
  25   int64 min_delay;
  26   int64 max_delay;
  27 };
  28
  29 // Class to verify retries take place using the exponential backoff algorithm.
  30 class RetryVerifier {
  31  public:
  32   static const int kMaxRetry = 3;
  33   RetryVerifier();
  34   ~RetryVerifier();
  35   int retry_count() const { return retry_count_; }
  36
  37   // Initialize with the current sync session snapshot. Using the snapshot
  38   // we will figure out when the first retry sync happened.
  39   void Initialize(const syncer::sessions::SyncSessionSnapshot& snap);
  40   void VerifyRetryInterval(
  41       const syncer::sessions::SyncSessionSnapshot& snap);
  42   bool done() const { return done_; }
  43   bool Succeeded() const { return done() && success_; }
  44
  45  private:
  46   int retry_count_;
  47   base::Time last_sync_time_;
  48   DelayInfo delay_table_[kMaxRetry];
  49   bool success_;
  50   bool done_;
  51   DISALLOW_COPY_AND_ASSIGN(RetryVerifier);
  52 };
  53
  54 }  // namespace browser_sync
  55
  56 #endif  // CHROME_BROWSER_SYNC_RETRY_VERIFIER_H_