chrome/browser/chromeos/geolocation/simple_geolocation_request.h

   1 // Copyright 2014 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_CHROMEOS_GEOLOCATION_SIMPLE_GEOLOCATION_REQUEST_H_
   6 #define CHROME_BROWSER_CHROMEOS_GEOLOCATION_SIMPLE_GEOLOCATION_REQUEST_H_
   7
   8 #include "base/basictypes.h"
   9 #include "base/callback.h"
  10 #include "base/compiler_specific.h"
  11 #include "base/memory/ref_counted.h"
  12 #include "base/memory/scoped_ptr.h"
  13 #include "base/threading/thread_checker.h"
  14 #include "base/timer/timer.h"
  15 #include "chrome/browser/chromeos/geolocation/geoposition.h"
  16 #include "net/url_request/url_fetcher.h"
  17 #include "net/url_request/url_fetcher_delegate.h"
  18 #include "url/gurl.h"
  19
  20 namespace net {
  21 class URLRequestContextGetter;
  22 }
  23
  24 namespace chromeos {
  25
  26 // Sends request to a server to get local geolocation information.
  27 // It performs formatting of the request and interpretation of the response.
  28 // Request is owned and destroyed by caller (usually SimpleGeolocationProvider).
  29 // - If error occurs, request is retried until timeout.
  30 // - On successul response, callback is called.
  31 // - On timeout, callback with last (failed) position is called.
  32 // (position.status is set to STATUS_TIMEOUT.)
  33 // - If request is destroyed while callback has not beed called yet, request
  34 // is silently cancelled.
  35 class SimpleGeolocationRequest : private net::URLFetcherDelegate {
  36  public:
  37   // Called when a new geo geolocation information is available.
  38   // The second argument indicates whether there was a server error or not.
  39   // It is true when there was a server or network error - either no response
  40   // or a 500 error code.
  41   typedef base::Callback<void(const Geoposition& /* position*/,
  42                               bool /* server_error */,
  43                               const base::TimeDelta elapsed)> ResponseCallback;
  44
  45   // |url| is the server address to which the request wil be sent.
  46   // |timeout| retry request on error until timeout.
  47   SimpleGeolocationRequest(net::URLRequestContextGetter* url_context_getter,
  48                            const GURL& service_url,
  49                            base::TimeDelta timeout);
  50
  51   virtual ~SimpleGeolocationRequest();
  52
  53   // Initiates request.
  54   // Note: if request object is destroyed before callback is called,
  55   // request will be silently cancelled.
  56   void MakeRequest(const ResponseCallback& callback);
  57
  58  private:
  59   // net::URLFetcherDelegate
  60   virtual void OnURLFetchComplete(const net::URLFetcher* source) OVERRIDE;
  61
  62   // Start new request.
  63   void StartRequest();
  64
  65   // Schedules retry.
  66   void Retry(bool server_error);
  67
  68   // Run callback and destroy "this".
  69   void ReplyAndDestroySelf(const base::TimeDelta elapsed, bool server_error);
  70
  71   // Called by timeout_timer_ .
  72   void OnTimeout();
  73
  74   scoped_refptr<net::URLRequestContextGetter> url_context_getter_;
  75
  76   // Service URL from constructor arguments.
  77   const GURL service_url_;
  78
  79   ResponseCallback callback_;
  80
  81   // Actual URL with parameters.
  82   GURL request_url_;
  83
  84   scoped_ptr<net::URLFetcher> url_fetcher_;
  85
  86   // When request was actually started.
  87   base::Time request_started_at_;
  88
  89   const base::TimeDelta timeout_;
  90
  91   // Pending retry.
  92   base::OneShotTimer<SimpleGeolocationRequest> request_scheduled_;
  93
  94   // Stop request on timeout.
  95   base::OneShotTimer<SimpleGeolocationRequest> timeout_timer_;
  96
  97   // Number of retry attempts.
  98   unsigned retries_;
  99
 100   // This is updated on each retry.
 101   Geoposition position_;
 102
 103   // Creation and destruction should happen on the same thread.
 104   base::ThreadChecker thread_checker_;
 105
 106   DISALLOW_COPY_AND_ASSIGN(SimpleGeolocationRequest);
 107 };
 108
 109 }  // namespace chromeos
 110
 111 #endif  // CHROME_BROWSER_CHROMEOS_GEOLOCATION_SIMPLE_GEOLOCATION_REQUEST_H_