// Copyright (c) 2012 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 EXTENSIONS_BROWSER_EXTENSION_THROTTLE_ENTRY_INTERFACE_H_
#define EXTENSIONS_BROWSER_EXTENSION_THROTTLE_ENTRY_INTERFACE_H_

#include <stdint.h>

#include <string>

#include "base/macros.h"
#include "base/memory/ref_counted.h"
#include "base/time/time.h"
#include "net/base/net_export.h"

namespace net {
class URLRequest;
}  // namespace net

namespace extensions {

// Interface provided on entries of the URL request throttler manager.
class ExtensionThrottleEntryInterface
    : public base::RefCountedThreadSafe<ExtensionThrottleEntryInterface> {
 public:
  ExtensionThrottleEntryInterface() {}

  // Returns true when we have encountered server errors and are doing
  // exponential back-off, unless the request has load flags that mean
  // it is likely to be user-initiated, or the NetworkDelegate returns
  // false for |CanThrottleRequest(request)|.
  //
  // URLRequestHttpJob checks this method prior to every request; it
  // cancels requests if this method returns true.
  virtual bool ShouldRejectRequest(const net::URLRequest& request) const = 0;

  // Calculates a recommended sending time for the next request and reserves it.
  // The sending time is not earlier than the current exponential back-off
  // release time or |earliest_time|. Moreover, the previous results of
  // the method are taken into account, in order to make sure they are spread
  // properly over time.
  // Returns the recommended delay before sending the next request, in
  // milliseconds. The return value is always positive or 0.
  // Although it is not mandatory, respecting the value returned by this method
  // is helpful to avoid traffic overload.
  virtual int64_t ReserveSendingTimeForNextRequest(
      const base::TimeTicks& earliest_time) = 0;

  // Returns the time after which requests are allowed.
  virtual base::TimeTicks GetExponentialBackoffReleaseTime() const = 0;

  // This method needs to be called each time a response is received.
  virtual void UpdateWithResponse(int status_code) = 0;

  // Lets higher-level modules, that know how to parse particular response
  // bodies, notify of receiving malformed content for the given URL. This will
  // be handled by the throttler as if an HTTP 503 response had been received to
  // the request, i.e. it will count as a failure, unless the HTTP response code
  // indicated is already one of those that will be counted as an error.
  virtual void ReceivedContentWasMalformed(int response_code) = 0;

  // Get the URL ID associated with this entry. Should only be used for
  // debugging purpose.
  virtual const std::string& GetURLIdForDebugging() const = 0;

 protected:
  friend class base::RefCountedThreadSafe<ExtensionThrottleEntryInterface>;
  virtual ~ExtensionThrottleEntryInterface() {}

 private:
  friend class base::RefCounted<ExtensionThrottleEntryInterface>;
  DISALLOW_COPY_AND_ASSIGN(ExtensionThrottleEntryInterface);
};

}  // namespace extensions

#endif  // EXTENSIONS_BROWSER_EXTENSION_THROTTLE_ENTRY_INTERFACE_H_