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      1 // Copyright (c) 2013 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_RENDERER_NET_NET_ERROR_HELPER_H_
      6 #define CHROME_RENDERER_NET_NET_ERROR_HELPER_H_
      7 
      8 #include <string>
      9 
     10 #include "chrome/common/net/net_error_info.h"
     11 #include "content/public/renderer/render_view_observer.h"
     12 #include "third_party/WebKit/public/platform/WebURLError.h"
     13 
     14 namespace base {
     15 class DictionaryValue;
     16 }
     17 
     18 namespace blink {
     19 class WebFrame;
     20 }
     21 
     22 // Listens for NetErrorInfo messages from the NetErrorTabHelper on the
     23 // browser side and updates the error page with more details (currently, just
     24 // DNS probe results) if/when available.
     25 class NetErrorHelper : public content::RenderViewObserver {
     26  public:
     27   explicit NetErrorHelper(content::RenderView* render_view);
     28   virtual ~NetErrorHelper();
     29 
     30   // RenderViewObserver implementation.
     31   virtual void DidStartProvisionalLoad(blink::WebFrame* frame) OVERRIDE;
     32   virtual void DidFailProvisionalLoad(
     33       blink::WebFrame* frame,
     34       const blink::WebURLError& error) OVERRIDE;
     35   virtual void DidCommitProvisionalLoad(
     36       blink::WebFrame* frame,
     37       bool is_new_navigation) OVERRIDE;
     38   virtual void DidFinishLoad(blink::WebFrame* frame) OVERRIDE;
     39 
     40   // IPC::Listener implementation.
     41   virtual bool OnMessageReceived(const IPC::Message& message) OVERRIDE;
     42 
     43   // Examines |frame| and |error| to see if this is an error worthy of a DNS
     44   // probe.  If it is, initializes |error_strings| based on |error|,
     45   // |is_failed_post|, and |locale| with suitable strings and returns true.
     46   // If not, returns false, in which case the caller should look up error
     47   // strings directly using LocalizedError::GetNavigationErrorStrings.
     48   static bool GetErrorStringsForDnsProbe(
     49       blink::WebFrame* frame,
     50       const blink::WebURLError& error,
     51       bool is_failed_post,
     52       const std::string& locale,
     53       const std::string& accept_languages,
     54       base::DictionaryValue* error_strings);
     55 
     56  protected:
     57   // These methods handle tracking the actual state of the page; this allows
     58   // unit-testing of the state tracking without having to mock out WebFrames
     59   // and such.
     60   void OnStartLoad(bool is_main_frame, bool is_error_page);
     61   void OnFailLoad(bool is_main_frame, bool is_dns_error);
     62   void OnCommitLoad(bool is_main_frame);
     63   void OnFinishLoad(bool is_main_frame);
     64 
     65   void OnNetErrorInfo(int status);
     66 
     67   // |UpdateErrorPage| is virtual so it can be mocked out in the unittest.
     68   virtual void UpdateErrorPage();
     69 
     70   // The last DnsProbeStatus received from the browser.
     71   chrome_common_net::DnsProbeStatus last_probe_status_;
     72 
     73  private:
     74   blink::WebURLError GetUpdatedError() const;
     75 
     76   // Whether the last provisional load started was for an error page.
     77   bool last_start_was_error_page_;
     78 
     79   // Whether the last provisional load failure failed with a DNS error.
     80   bool last_fail_was_dns_error_;
     81 
     82   // Ideally, this would be simply "last_commit_was_dns_error_page_".
     83   //
     84   // Unfortunately, that breaks if two DNS errors occur in a row; after the
     85   // second failure, but before the second page commits, the helper can receive
     86   // probe results.  If all it knows is that the last commit was a DNS error
     87   // page, it will cheerfully forward the results for the second probe to the
     88   // first page.
     89   //
     90   // Thus, the semantics of this flag are a little weird.  It is set whenever
     91   // a DNS error page commits, and cleared whenever any other page commits,
     92   // but it is also cleared whenever a DNS error occurs, to prevent the race
     93   // described above.
     94   bool forwarding_probe_results_;
     95 
     96   // The last main frame error seen by the helper.
     97   blink::WebURLError last_error_;
     98 
     99   bool is_failed_post_;
    100 };
    101 
    102 #endif  // CHROME_RENDERER_NET_NET_ERROR_HELPER_H_
    103