src/chrome/browser/net/preconnect.cc

   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 #include "chrome/browser/net/preconnect.h"
   6
   7 #include "base/bind.h"
   8 #include "base/logging.h"
   9 #include "base/metrics/histogram.h"
  10 #include "content/public/browser/browser_thread.h"
  11 #include "net/base/net_log.h"
  12 #include "net/http/http_network_session.h"
  13 #include "net/http/http_request_info.h"
  14 #include "net/http/http_stream_factory.h"
  15 #include "net/http/http_transaction_factory.h"
  16 #include "net/ssl/ssl_config_service.h"
  17 #include "net/url_request/http_user_agent_settings.h"
  18 #include "net/url_request/url_request_context.h"
  19 #include "net/url_request/url_request_context_getter.h"
  20
  21 using content::BrowserThread;
  22
  23 namespace chrome_browser_net {
  24
  25 void PreconnectOnUIThread(
  26     const GURL& url,
  27     const GURL& first_party_for_cookies,
  28     UrlInfo::ResolutionMotivation motivation,
  29     int count,
  30     net::URLRequestContextGetter* getter) {
  31   // Prewarm connection to Search URL.
  32   BrowserThread::PostTask(
  33       BrowserThread::IO,
  34       FROM_HERE,
  35       base::Bind(&PreconnectOnIOThread, url, first_party_for_cookies,
  36                  motivation, count, make_scoped_refptr(getter)));
  37   return;
  38 }
  39
  40
  41 void PreconnectOnIOThread(
  42     const GURL& url,
  43     const GURL& first_party_for_cookies,
  44     UrlInfo::ResolutionMotivation motivation,
  45     int count,
  46     net::URLRequestContextGetter* getter) {
  47   if (!BrowserThread::CurrentlyOn(BrowserThread::IO)) {
  48     LOG(DFATAL) << "This must be run only on the IO thread.";
  49     return;
  50   }
  51   if (!getter)
  52     return;
  53   // We are now commited to doing the async preconnection call.
  54   UMA_HISTOGRAM_ENUMERATION("Net.PreconnectMotivation", motivation,
  55                             UrlInfo::MAX_MOTIVATED);
  56
  57   net::URLRequestContext* context = getter->GetURLRequestContext();
  58   net::HttpTransactionFactory* factory = context->http_transaction_factory();
  59   net::HttpNetworkSession* session = factory->GetSession();
  60
  61   std::string user_agent;
  62   if (context->http_user_agent_settings())
  63     user_agent = context->http_user_agent_settings()->GetUserAgent();
  64   net::HttpRequestInfo request_info;
  65   request_info.url = url;
  66   request_info.method = "GET";
  67   request_info.extra_headers.SetHeader(net::HttpRequestHeaders::kUserAgent,
  68                                        user_agent);
  69
  70   net::NetworkDelegate* delegate = context->network_delegate();
  71   if (delegate->CanEnablePrivacyMode(url, first_party_for_cookies))
  72     request_info.privacy_mode = net::PRIVACY_MODE_ENABLED;
  73
  74   // It almost doesn't matter whether we use net::LOWEST or net::HIGHEST
  75   // priority here, as we won't make a request, and will surrender the created
  76   // socket to the pool as soon as we can.  However, we would like to mark the
  77   // speculative socket as such, and IF we use a net::LOWEST priority, and if
  78   // a navigation asked for a socket (after us) then it would get our socket,
  79   // and we'd get its later-arriving socket, which might make us record that
  80   // the speculation didn't help :-/.  By using net::HIGHEST, we ensure that
  81   // a socket is given to us if "we asked first" and this allows us to mark it
  82   // as speculative, and better detect stats (if it gets used).
  83   // TODO(jar): histogram to see how often we accidentally use a previously-
  84   // unused socket, when a previously used socket was available.
  85   net::RequestPriority priority = net::HIGHEST;
  86
  87   // Translate the motivation from UrlRequest motivations to HttpRequest
  88   // motivations.
  89   switch (motivation) {
  90     case UrlInfo::OMNIBOX_MOTIVATED:
  91       request_info.motivation = net::HttpRequestInfo::OMNIBOX_MOTIVATED;
  92       break;
  93     case UrlInfo::LEARNED_REFERAL_MOTIVATED:
  94       request_info.motivation = net::HttpRequestInfo::PRECONNECT_MOTIVATED;
  95       break;
  96     case UrlInfo::MOUSE_OVER_MOTIVATED:
  97     case UrlInfo::SELF_REFERAL_MOTIVATED:
  98     case UrlInfo::EARLY_LOAD_MOTIVATED:
  99       request_info.motivation = net::HttpRequestInfo::EARLY_LOAD_MOTIVATED;
 100       break;
 101     default:
 102       // Other motivations should never happen here.
 103       NOTREACHED();
 104       break;
 105   }
 106
 107   // Setup the SSL Configuration.
 108   net::SSLConfig ssl_config;
 109   session->ssl_config_service()->GetSSLConfig(&ssl_config);
 110   if (session->http_stream_factory()->has_next_protos())
 111     ssl_config.next_protos = session->http_stream_factory()->next_protos();
 112
 113   // All preconnects should perform EV certificate verification.
 114   ssl_config.verify_ev_cert = true;
 115
 116   net::HttpStreamFactory* http_stream_factory = session->http_stream_factory();
 117   http_stream_factory->PreconnectStreams(count, request_info, priority,
 118                                          ssl_config, ssl_config);
 119 }
 120
 121 }  // namespace chrome_browser_net