webkit/common/user_agent/user_agent.cc

   1 // Copyright 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 "webkit/common/user_agent/user_agent.h"
   6
   7 #include "base/lazy_instance.h"
   8 #include "base/logging.h"
   9 #include "base/strings/string_util.h"
  10 #include "base/strings/stringprintf.h"
  11 #include "base/synchronization/lock.h"
  12 #include "webkit/common/user_agent/user_agent_util.h"
  13
  14 namespace webkit_glue {
  15
  16 namespace {
  17
  18 class UserAgentState {
  19  public:
  20   UserAgentState();
  21   ~UserAgentState();
  22
  23   void Set(const std::string& user_agent, bool overriding);
  24   const std::string& Get(const GURL& url) const;
  25
  26  private:
  27   mutable std::string user_agent_;
  28   // The UA string when we're pretending to be Mac Safari or Win Firefox.
  29   mutable std::string user_agent_for_spoofing_hack_;
  30
  31   mutable bool user_agent_requested_;
  32   bool user_agent_is_overridden_;
  33
  34   // This object can be accessed from multiple threads, so use a lock around
  35   // accesses to the data members.
  36   mutable base::Lock lock_;
  37 };
  38
  39 UserAgentState::UserAgentState()
  40     : user_agent_requested_(false),
  41       user_agent_is_overridden_(false) {
  42 }
  43
  44 UserAgentState::~UserAgentState() {
  45 }
  46
  47 void UserAgentState::Set(const std::string& user_agent, bool overriding) {
  48   base::AutoLock auto_lock(lock_);
  49   if (user_agent == user_agent_) {
  50     // We allow the user agent to be set multiple times as long as it
  51     // is set to the same value, in order to simplify unit testing
  52     // given g_user_agent is a global.
  53     return;
  54   }
  55   DCHECK(!user_agent.empty());
  56   DCHECK(!user_agent_requested_) << "Setting the user agent after someone has "
  57       "already requested it can result in unexpected behavior.";
  58   user_agent_is_overridden_ = overriding;
  59   user_agent_ = user_agent;
  60 }
  61
  62 bool IsMicrosoftSiteThatNeedsSpoofingForSilverlight(const GURL& url) {
  63 #if defined(OS_MACOSX) && !defined(OS_IOS)
  64   // The landing page for updating Silverlight gives a confusing experience
  65   // in browsers that Silverlight doesn't officially support; spoof as
  66   // Safari to reduce the chance that users won't complete updates.
  67   // Should be removed if the sniffing is removed: http://crbug.com/88211
  68   if (url.host() == "www.microsoft.com" &&
  69       StartsWithASCII(url.path(), "/getsilverlight", false)) {
  70     return true;
  71   }
  72 #endif
  73   return false;
  74 }
  75
  76 bool IsYahooSiteThatNeedsSpoofingForSilverlight(const GURL& url) {
  77 #if defined(OS_MACOSX) && !defined(OS_IOS)
  78   if ((url.host() == "downloads.yahoo.co.jp" &&
  79       StartsWithASCII(url.path(), "/docs/silverlight/", true)) ||
  80       url.host() == "gyao.yahoo.co.jp") {
  81     return true;
  82   }
  83 #elif defined(OS_WIN)
  84   if (url.host() == "promotion.shopping.yahoo.co.jp") {
  85     return true;
  86   }
  87 #endif
  88   return false;
  89 }
  90
  91 const std::string& UserAgentState::Get(const GURL& url) const {
  92   base::AutoLock auto_lock(lock_);
  93   user_agent_requested_ = true;
  94
  95   DCHECK(!user_agent_.empty());
  96
  97   // Workarounds for sites that use misguided UA sniffing.
  98   if (!user_agent_is_overridden_) {
  99     if (IsMicrosoftSiteThatNeedsSpoofingForSilverlight(url) ||
 100         IsYahooSiteThatNeedsSpoofingForSilverlight(url)) {
 101       if (user_agent_for_spoofing_hack_.empty()) {
 102 #if defined(OS_MACOSX) && !defined(OS_IOS)
 103         user_agent_for_spoofing_hack_ =
 104             BuildUserAgentFromProduct("Version/5.1.1 Safari/534.51.22");
 105 #elif defined(OS_WIN)
 106         // Pretend to be Firefox. Silverlight doesn't support Win Safari.
 107         base::StringAppendF(
 108             &user_agent_for_spoofing_hack_,
 109             "Mozilla/5.0 (%s) Gecko/20100101 Firefox/8.0",
 110             webkit_glue::BuildOSCpuInfo().c_str());
 111 #endif
 112       }
 113       DCHECK(!user_agent_for_spoofing_hack_.empty());
 114       return user_agent_for_spoofing_hack_;
 115     }
 116   }
 117
 118   return user_agent_;
 119 }
 120
 121 base::LazyInstance<UserAgentState> g_user_agent = LAZY_INSTANCE_INITIALIZER;
 122
 123 }  // namespace
 124
 125 void SetUserAgent(const std::string& user_agent, bool overriding) {
 126   g_user_agent.Get().Set(user_agent, overriding);
 127 }
 128
 129 const std::string& GetUserAgent(const GURL& url) {
 130   return g_user_agent.Get().Get(url);
 131 }
 132
 133 }  // namespace webkit_glue