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      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_
     74