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      1 // Copyright (c) 2010 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 #include "chrome/browser/net/connect_interceptor.h"
      6 
      7 #include "chrome/browser/net/predictor_api.h"
      8 #include "net/base/load_flags.h"
      9 
     10 namespace chrome_browser_net {
     11 
     12 ConnectInterceptor::ConnectInterceptor() {
     13   net::URLRequest::RegisterRequestInterceptor(this);
     14 }
     15 
     16 ConnectInterceptor::~ConnectInterceptor() {
     17   net::URLRequest::UnregisterRequestInterceptor(this);
     18 }
     19 
     20 net::URLRequestJob* ConnectInterceptor::MaybeIntercept(
     21     net::URLRequest* request) {
     22   GURL request_scheme_host(request->url().GetWithEmptyPath());
     23 
     24   // Learn what URLs are likely to be needed during next startup.
     25   LearnAboutInitialNavigation(request_scheme_host);
     26 
     27   bool redirected_host = false;
     28   if (request->referrer().empty()) {
     29     if (request->url() != request->original_url()) {
     30       // This request was completed with a redirect.
     31       GURL original_scheme_host(request->original_url().GetWithEmptyPath());
     32       if (request_scheme_host != original_scheme_host) {
     33         redirected_host = true;
     34         // Don't learn from redirects that take path as an argument, but do
     35         // learn from short-hand typing entries, such as "cnn.com" redirects to
     36         // "www.cnn.com".  We can't just check for has_path(), as a mere "/"
     37         // will count as a path, so we check that the path is at most a "/"
     38         // (1 character long) to decide the redirect is "definitive" and has no
     39         // significant path.
     40         // TODO(jar): It may be ok to learn from all redirects, as the adaptive
     41         // system will not respond until several identical redirects have taken
     42         // place.  Hence a use of a path (that changes) wouldn't really be
     43         // learned from anyway.
     44         if (request->original_url().path().length() <= 1) {
     45           // TODO(jar): These definite redirects could be learned much faster.
     46           LearnFromNavigation(original_scheme_host, request_scheme_host);
     47         }
     48       }
     49     }
     50   } else {
     51     GURL referring_scheme_host = GURL(request->referrer()).GetWithEmptyPath();
     52     bool is_subresource = !(request->load_flags() & net::LOAD_MAIN_FRAME);
     53     // Learn about our referring URL, for use in the future.
     54     if (is_subresource)
     55       LearnFromNavigation(referring_scheme_host, request_scheme_host);
     56     if (referring_scheme_host == request_scheme_host) {
     57       // We've already made any/all predictions when we navigated to the
     58       // referring host, so we can bail out here.
     59       return NULL;
     60     }
     61   }
     62 
     63   // Subresources for main frames usually get predicted when we detected the
     64   // main frame request - way back in RenderViewHost::Navigate.  So only handle
     65   // predictions now for subresources or for redirected hosts.
     66   if ((request->load_flags() & net::LOAD_SUB_FRAME) || redirected_host)
     67     PredictFrameSubresources(request_scheme_host);
     68   return NULL;
     69 }
     70 
     71 net::URLRequestJob* ConnectInterceptor::MaybeInterceptResponse(
     72     net::URLRequest* request) {
     73   return NULL;
     74 }
     75 
     76 net::URLRequestJob* ConnectInterceptor::MaybeInterceptRedirect(
     77     net::URLRequest* request,
     78     const GURL& location) {
     79   return NULL;
     80 }
     81 
     82 }  // namespace chrome_browser_net
     83