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#include "chrome/browser/net/connect_interceptor.h"
6
7#include "chrome/browser/net/predictor.h"
8#include "net/base/load_flags.h"
9#include "net/url_request/url_request.h"
10
11namespace chrome_browser_net {
12
13ConnectInterceptor::ConnectInterceptor(Predictor* predictor)
14    : timed_cache_(base::TimeDelta::FromSeconds(
15          Predictor::kMaxUnusedSocketLifetimeSecondsWithoutAGet)),
16      predictor_(predictor) {
17  DCHECK(predictor);
18}
19
20ConnectInterceptor::~ConnectInterceptor() {
21}
22
23void ConnectInterceptor::WitnessURLRequest(net::URLRequest* request) {
24  GURL request_scheme_host(Predictor::CanonicalizeUrl(request->url()));
25  if (request_scheme_host == GURL::EmptyGURL())
26    return;
27
28  // Learn what URLs are likely to be needed during next startup.
29  predictor_->LearnAboutInitialNavigation(request_scheme_host);
30
31  bool redirected_host = false;
32  bool is_subresource = !(request->load_flags() & net::LOAD_MAIN_FRAME);
33  if (request->referrer().empty()) {
34    if (request->url() != request->original_url()) {
35      // This request was completed with a redirect.
36      GURL original_scheme_host(request->original_url().GetWithEmptyPath());
37      if (request_scheme_host != original_scheme_host) {
38        redirected_host = true;
39        // Don't learn from redirects that take path as an argument, but do
40        // learn from short-hand typing entries, such as "cnn.com" redirects to
41        // "www.cnn.com".  We can't just check for has_path(), as a mere "/"
42        // will count as a path, so we check that the path is at most a "/"
43        // (1 character long) to decide the redirect is "definitive" and has no
44        // significant path.
45        // TODO(jar): It may be ok to learn from all redirects, as the adaptive
46        // system will not respond until several identical redirects have taken
47        // place.  Hence a use of a path (that changes) wouldn't really be
48        // learned from anyway.
49        if (request->original_url().path().length() <= 1 &&
50            timed_cache_.WasRecentlySeen(original_scheme_host)) {
51          // TODO(jar): These definite redirects could be learned much faster.
52          predictor_->LearnFromNavigation(original_scheme_host,
53                                          request_scheme_host);
54        }
55      }
56    }
57  } else {
58    GURL referring_scheme_host = GURL(request->referrer()).GetWithEmptyPath();
59    // Learn about our referring URL, for use in the future.
60    if (is_subresource && timed_cache_.WasRecentlySeen(referring_scheme_host))
61      predictor_->LearnFromNavigation(referring_scheme_host,
62                                      request_scheme_host);
63    if (referring_scheme_host == request_scheme_host) {
64      // We've already made any/all predictions when we navigated to the
65      // referring host, so we can bail out here.
66      // We don't update the RecentlySeen() time because any preconnections
67      // need to be made at the first navigation (i.e., when referer was loaded)
68      // and wouldn't have waited for this current request navigation.
69      return;
70    }
71  }
72  timed_cache_.SetRecentlySeen(request_scheme_host);
73
74  // Subresources for main frames usually get predicted when we detected the
75  // main frame request - way back in RenderViewHost::Navigate.  So only handle
76  // predictions now for subresources or for redirected hosts.
77  if ((request->load_flags() & net::LOAD_SUB_FRAME) || redirected_host)
78    predictor_->PredictFrameSubresources(request_scheme_host,
79                                         request->first_party_for_cookies());
80  return;
81}
82
83}  // namespace chrome_browser_net
84