Remove minidump analysis aides from URLRequestThrottlerManager. New

net/base/backoff_entry.h

+// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef NET_BASE_BACKOFF_ITEM_H_
+#define NET_BASE_BACKOFF_ITEM_H_
+#pragma once
+
+#include "base/threading/non_thread_safe.h"
+#include "base/time.h"
+
+namespace net {
+
+// Provides the core logic needed for randomized exponential back-off
+// on requests to a given resource, given a back-off policy.
+//
+// This utility class knows nothing about network specifics; it is
+// intended for reuse in various networking scenarios.
+class BackoffEntry : public base::NonThreadSafe {
+ public:
+
+  // The set of parameters that define a back-off policy.
+  struct Policy {
+    // Number of initial errors (in sequence) to ignore before applying
+    // exponential back-off rules.
+    int num_errors_to_ignore_;
+
+    // Initial delay for exponential back-off.
+    int initial_backoff_ms_;
+
+    // Factor by which the waiting time will be multiplied.
+    double multiply_factor_;
+
+    // Fuzzing percentage. ex: 10% will spread requests randomly
+    // between 90%-100% of the calculated time.
+    double jitter_factor_;
+
+    // Maximum amount of time we are willing to delay our request.
+    int maximum_backoff_ms_;
+
+    // Time to keep an entry from being discarded even when it
+    // has no significant state, -1 to never discard.
+    int entry_lifetime_ms_;
+  };
+
+  // Lifetime of policy must enclose lifetime of BackoffEntry. The
+  // pointer must be valid but is not dereferenced during construction.
+  BackoffEntry(const Policy* policy);
+  ~BackoffEntry();
+
+  // Inform this item that a request for the network resource it is
+  // tracking was made, and whether it failed or succeeded.
+  void InformOfRequest(bool succeeded);
+
+  // Returns true if a request for the resource this item tracks should
+  // be rejected at the present time due to exponential backoff policy.
+  bool ShouldRejectRequest() const;
+
+  // Returns the absolute time after which this entry (given its present
+  // state) will no longer reject requests.
+  base::TimeTicks GetReleaseTime() const;
+
+  // Causes this object reject requests until the specified absolute time.
+  // This can be used to e.g. implement support for a Retry-After header.
+  void SetCustomReleaseTime(const base::TimeTicks release_time);
+
+  // Returns true if this object has no significant state (i.e. you could
+  // just as well start with a fresh BackoffEntry object), and hasn't
+  // had for Policy::entry_lifetime_ms_.
+  bool CanDiscard() const;
+
+ protected:
+
+  // Equivalent to TimeTicks::Now(), virtual so unit tests can override.
+  virtual base::TimeTicks GetTimeNow() const;
+
+  // Calculates when requests should again be allowed through.
+  base::TimeTicks CalculateReleaseTime() const;
+
+ private:
+
+  // Timestamp calculated by the exponential back-off algorithm at which we are
+  // allowed to start sending requests again.
+  base::TimeTicks exponential_backoff_release_time_;
+
+  // Counts request errors; reset on success.
+  int failure_count_;
+
+  const Policy* policy_;
+
+  DISALLOW_COPY_AND_ASSIGN(BackoffEntry);
+};
+
+}  // namespace net
+
+#endif  // NET_BASE_BACKOFF_ITEM_H_