text: // Copyright (c) 2012 The Chromium Authors. All rights reserved.
  // Use of this source code is governed by a BSD-style license that can be
  // found in the LICENSE file.
  
  #ifndef REMOTING_HOST_SIGNALING_CONNECTOR_H_
  #define REMOTING_HOST_SIGNALING_CONNECTOR_H_
  
  #include "base/basictypes.h"
  #include "base/memory/weak_ptr.h"
  #include "base/threading/non_thread_safe.h"
  #include "base/timer/timer.h"
  #include "google_apis/gaia/gaia_oauth_client.h"
  #include "net/base/network_change_notifier.h"
  #include "remoting/jingle_glue/xmpp_signal_strategy.h"
  
  namespace net {
  class URLFetcher;
  class URLRequestContextGetter;
  }  // namespace net
  
  namespace remoting {
  
  class DnsBlackholeChecker;
  
  // SignalingConnector listens for SignalStrategy status notifications
  // and attempts to keep it connected when possible. When signalling is
  // not connected it keeps trying to reconnect it until it is
  // connected. It limits connection attempt rate using exponential
  // backoff. It also monitors network state and reconnects signalling
  // whenever connection type changes or IP address changes.
  class SignalingConnector
      : public base::SupportsWeakPtr<SignalingConnector>,
        public base::NonThreadSafe,
        public SignalStrategy::Listener,
        public net::NetworkChangeNotifier::ConnectionTypeObserver,
        public net::NetworkChangeNotifier::IPAddressObserver,
        public gaia::GaiaOAuthClient::Delegate {
   public:
    // This structure contains information required to perform
    // authentication to OAuth2.
    struct OAuthCredentials {
      OAuthCredentials(const std::string& login_value,
                       const std::string& refresh_token_value);
  
      // The user's account name (i.e. their email address).
      std::string login;
  
      // Token delegating authority to us to act as the user.
      std::string refresh_token;
    };
  
    // The |auth_failed_callback| is called when authentication fails.
    SignalingConnector(
        XmppSignalStrategy* signal_strategy,
        scoped_refptr<net::URLRequestContextGetter> url_request_context_getter,
        scoped_ptr<DnsBlackholeChecker> dns_blackhole_checker,
        const base::Closure& auth_failed_callback);
    virtual ~SignalingConnector();
  
    // May be called immediately after the constructor to enable OAuth
    // access token updating.
    void EnableOAuth(scoped_ptr<OAuthCredentials> oauth_credentials);
  
    // SignalStrategy::Listener interface.
    virtual void OnSignalStrategyStateChange(
        SignalStrategy::State state) OVERRIDE;
    virtual bool OnSignalStrategyIncomingStanza(
        const buzz::XmlElement* stanza) OVERRIDE;
  
    // NetworkChangeNotifier::ConnectionTypeObserver interface.
    virtual void OnConnectionTypeChanged(
        net::NetworkChangeNotifier::ConnectionType type) OVERRIDE;
  
    // NetworkChangeNotifier::IPAddressObserver interface.
    virtual void OnIPAddressChanged() OVERRIDE;
  
    // gaia::GaiaOAuthClient::Delegate interface.
    virtual void OnGetTokensResponse(const std::string& user_email,
                                     const std::string& access_token,
                                     int expires_seconds) OVERRIDE;
    virtual void OnRefreshTokenResponse(const std::string& access_token,
                                        int expires_in_seconds) OVERRIDE;
    virtual void OnGetUserEmailResponse(const std::string& user_email) OVERRIDE;
    virtual void OnOAuthError() OVERRIDE;
    virtual void OnNetworkError(int response_code) OVERRIDE;
  
   private:
    void ScheduleTryReconnect();
    void ResetAndTryReconnect();
    void TryReconnect();
    void OnDnsBlackholeCheckerDone(bool allow);
  
    void RefreshOAuthToken();
  
    XmppSignalStrategy* signal_strategy_;
    scoped_refptr<net::URLRequestContextGetter> url_request_context_getter_;
    base::Closure auth_failed_callback_;
  
    scoped_ptr<OAuthCredentials> oauth_credentials_;
    scoped_ptr<gaia::GaiaOAuthClient> gaia_oauth_client_;
    scoped_ptr<DnsBlackholeChecker> dns_blackhole_checker_;
  
    // Number of times we tried to connect without success.
    int reconnect_attempts_;
  
    bool refreshing_oauth_token_;
    std::string oauth_access_token_;
    base::Time auth_token_expiry_time_;
  
    base::OneShotTimer<SignalingConnector> timer_;
  
    DISALLOW_COPY_AND_ASSIGN(SignalingConnector);
  };
  
  }  // namespace remoting
  
  #endif  // REMOTING_HOST_SIGNALING_CONNECTOR_H_
  