preconnect.cc revision 5821806d5e7f356e8fa4b058a389a808ea183019 
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/base/ssl_config_service.h"
13#include "net/http/http_network_session.h"
14#include "net/http/http_request_info.h"
15#include "net/http/http_stream_factory.h"
16#include "net/http/http_transaction_factory.h"
17#include "net/url_request/url_request_context.h"
18#include "net/url_request/url_request_context_getter.h"
19
20using content::BrowserThread;
21
22namespace chrome_browser_net {
23
24void PreconnectOnUIThread(
25    const GURL& url,
26    UrlInfo::ResolutionMotivation motivation,
27    int count,
28    net::URLRequestContextGetter* getter) {
29  // Prewarm connection to Search URL.
30  BrowserThread::PostTask(
31      BrowserThread::IO,
32      FROM_HERE,
33      base::Bind(&PreconnectOnIOThread, url, motivation, count,
34                 make_scoped_refptr(getter)));
35  return;
36}
37
38
39void PreconnectOnIOThread(
40    const GURL& url,
41    UrlInfo::ResolutionMotivation motivation,
42    int count,
43    net::URLRequestContextGetter* getter) {
44  if (!BrowserThread::CurrentlyOn(BrowserThread::IO)) {
45    LOG(DFATAL) << "This must be run only on the IO thread.";
46    return;
47  }
48  if (!getter)
49    return;
50  // We are now commited to doing the async preconnection call.
51  UMA_HISTOGRAM_ENUMERATION("Net.PreconnectMotivation", motivation,
52                            UrlInfo::MAX_MOTIVATED);
53
54  net::URLRequestContext* context = getter->GetURLRequestContext();
55  net::HttpTransactionFactory* factory = context->http_transaction_factory();
56  net::HttpNetworkSession* session = factory->GetSession();
57
58  net::HttpRequestInfo request_info;
59  request_info.url = url;
60  request_info.method = "GET";
61  request_info.extra_headers.SetHeader(net::HttpRequestHeaders::kUserAgent,
62                                       context->GetUserAgent(url));
63  // It almost doesn't matter whether we use net::LOWEST or net::HIGHEST
64  // priority here, as we won't make a request, and will surrender the created
65  // socket to the pool as soon as we can.  However, we would like to mark the
66  // speculative socket as such, and IF we use a net::LOWEST priority, and if
67  // a navigation asked for a socket (after us) then it would get our socket,
68  // and we'd get its later-arriving socket, which might make us record that
69  // the speculation didn't help :-/.  By using net::HIGHEST, we ensure that
70  // a socket is given to us if "we asked first" and this allows us to mark it
71  // as speculative, and better detect stats (if it gets used).
72  // TODO(jar): histogram to see how often we accidentally use a previously-
73  // unused socket, when a previously used socket was available.
74  request_info.priority = net::HIGHEST;
75
76  // Translate the motivation from UrlRequest motivations to HttpRequest
77  // motivations.
78  switch (motivation) {
79    case UrlInfo::OMNIBOX_MOTIVATED:
80      request_info.motivation = net::HttpRequestInfo::OMNIBOX_MOTIVATED;
81      break;
82    case UrlInfo::LEARNED_REFERAL_MOTIVATED:
83      request_info.motivation = net::HttpRequestInfo::PRECONNECT_MOTIVATED;
84      break;
85    case UrlInfo::SELF_REFERAL_MOTIVATED:
86    case UrlInfo::EARLY_LOAD_MOTIVATED:
87      request_info.motivation = net::HttpRequestInfo::EARLY_LOAD_MOTIVATED;
88      break;
89    default:
90      // Other motivations should never happen here.
91      NOTREACHED();
92      break;
93  }
94
95  // Setup the SSL Configuration.
96  net::SSLConfig ssl_config;
97  session->ssl_config_service()->GetSSLConfig(&ssl_config);
98  if (session->http_stream_factory()->has_next_protos())
99    ssl_config.next_protos = session->http_stream_factory()->next_protos();
100
101  // All preconnects should perform EV certificate verification.
102  ssl_config.verify_ev_cert = true;
103
104  net::HttpStreamFactory* http_stream_factory = session->http_stream_factory();
105  http_stream_factory->PreconnectStreams(count, request_info, ssl_config,
106                                         ssl_config);
107}
108
109}  // namespace chrome_browser_net
110