net/url_request/url_request_throttler_entry_interface.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 NET_URL_REQUEST_URL_REQUEST_THROTTLER_ENTRY_INTERFACE_H_
   6 #define NET_URL_REQUEST_URL_REQUEST_THROTTLER_ENTRY_INTERFACE_H_
   7
   8 #include <string>
   9
  10 #include "base/basictypes.h"
  11 #include "base/memory/ref_counted.h"
  12 #include "base/time/time.h"
  13 #include "net/base/net_export.h"
  14
  15 namespace net {
  16
  17 class URLRequest;
  18 class URLRequestThrottlerHeaderInterface;
  19
  20 // Interface provided on entries of the URL request throttler manager.
  21 class NET_EXPORT URLRequestThrottlerEntryInterface
  22     : public base::RefCountedThreadSafe<URLRequestThrottlerEntryInterface> {
  23  public:
  24   URLRequestThrottlerEntryInterface() {}
  25
  26   // Returns true when we have encountered server errors and are doing
  27   // exponential back-off, unless the request has load flags that mean
  28   // it is likely to be user-initiated, or the NetworkDelegate returns
  29   // false for |CanThrottleRequest(request)|.
  30   //
  31   // URLRequestHttpJob checks this method prior to every request; it
  32   // cancels requests if this method returns true.
  33   virtual bool ShouldRejectRequest(const URLRequest& request) const = 0;
  34
  35   // Calculates a recommended sending time for the next request and reserves it.
  36   // The sending time is not earlier than the current exponential back-off
  37   // release time or |earliest_time|. Moreover, the previous results of
  38   // the method are taken into account, in order to make sure they are spread
  39   // properly over time.
  40   // Returns the recommended delay before sending the next request, in
  41   // milliseconds. The return value is always positive or 0.
  42   // Although it is not mandatory, respecting the value returned by this method
  43   // is helpful to avoid traffic overload.
  44   virtual int64 ReserveSendingTimeForNextRequest(
  45       const base::TimeTicks& earliest_time) = 0;
  46
  47   // Returns the time after which requests are allowed.
  48   virtual base::TimeTicks GetExponentialBackoffReleaseTime() const = 0;
  49
  50   // This method needs to be called each time a response is received.
  51   virtual void UpdateWithResponse(
  52       const std::string& host,
  53       const URLRequestThrottlerHeaderInterface* response) = 0;
  54
  55   // Lets higher-level modules, that know how to parse particular response
  56   // bodies, notify of receiving malformed content for the given URL. This will
  57   // be handled by the throttler as if an HTTP 503 response had been received to
  58   // the request, i.e. it will count as a failure, unless the HTTP response code
  59   // indicated is already one of those that will be counted as an error.
  60   virtual void ReceivedContentWasMalformed(int response_code) = 0;
  61
  62  protected:
  63   friend class base::RefCountedThreadSafe<URLRequestThrottlerEntryInterface>;
  64   virtual ~URLRequestThrottlerEntryInterface() {}
  65
  66  private:
  67   friend class base::RefCounted<URLRequestThrottlerEntryInterface>;
  68   DISALLOW_COPY_AND_ASSIGN(URLRequestThrottlerEntryInterface);
  69 };
  70
  71 }  // namespace net
  72
  73 #endif  // NET_URL_REQUEST_URL_REQUEST_THROTTLER_ENTRY_INTERFACE_H_