Start calculating new combined NetworkChangeNotifier signal

net/base/network_change_notifier.cc

 // 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.
 
 #include "net/base/network_change_notifier.h"
 
 #include "base/metrics/histogram.h"
 #include "base/synchronization/lock.h"
 #include "build/build_config.h"
 #include "googleurl/src/gurl.h"
@@ skipping 17 matching lines @@
 // in ways that would require us to place locks around access to this object.
 // (The prohibition on global non-POD objects makes it tricky to do such a thing
 // anyway.)
 NetworkChangeNotifier* g_network_change_notifier = NULL;
 
 // Class factory singleton.
 NetworkChangeNotifierFactory* g_network_change_notifier_factory = NULL;
 
 class MockNetworkChangeNotifier : public NetworkChangeNotifier {
  public:
+  MockNetworkChangeNotifier()
+      : NetworkChangeNotifier(NetworkChangeCalculatorParams()) {}
   virtual ConnectionType GetCurrentConnectionType() const OVERRIDE {
     return CONNECTION_UNKNOWN;
   }
 };
 
 }  // namespace
 
 // The main observer class that records UMAs for network events.
 class HistogramWatcher
     : public NetworkChangeNotifier::ConnectionTypeObserver,
       public NetworkChangeNotifier::IPAddressObserver,
-      public NetworkChangeNotifier::DNSObserver {
+      public NetworkChangeNotifier::DNSObserver,
+      public NetworkChangeNotifier::NetworkChangeObserver {
  public:
   HistogramWatcher()
       : last_ip_address_change_(base::TimeTicks::Now()),
         last_connection_change_(base::TimeTicks::Now()),
         last_dns_change_(base::TimeTicks::Now()),
+        last_network_change_(base::TimeTicks::Now()),
         last_connection_type_(NetworkChangeNotifier::CONNECTION_UNKNOWN),
         offline_packets_received_(0) {}
 
   // Registers our three Observer implementations.  This is called from the
   // network thread so that our Observer implementations are also called
   // from the network thread.  This avoids multi-threaded race conditions
   // because the only other interface, |NotifyDataReceived| is also
   // only called from the network thread.
   void Init() {
     NetworkChangeNotifier::AddConnectionTypeObserver(this);
     NetworkChangeNotifier::AddIPAddressObserver(this);
     NetworkChangeNotifier::AddDNSObserver(this);
+    NetworkChangeNotifier::AddNetworkChangeObserver(this);
   }
 
   virtual ~HistogramWatcher() {}
 
   // NetworkChangeNotifier::IPAddressObserver implementation.
   virtual void OnIPAddressChanged() OVERRIDE {
     UMA_HISTOGRAM_MEDIUM_TIMES("NCN.IPAddressChange",
                                SinceLast(&last_ip_address_change_));
+    UMA_HISTOGRAM_MEDIUM_TIMES(
+        "NCN.ConnectionTypeChangeToIPAddressChange",
+        last_ip_address_change_ - last_connection_change_);
   }
 
   // NetworkChangeNotifier::ConnectionTypeObserver implementation.
   virtual void OnConnectionTypeChanged(
       NetworkChangeNotifier::ConnectionType type) OVERRIDE {
     if (type != NetworkChangeNotifier::CONNECTION_NONE) {
       UMA_HISTOGRAM_MEDIUM_TIMES("NCN.OnlineChange",
                                  SinceLast(&last_connection_change_));
 
       if (offline_packets_received_) {
         if ((last_connection_change_ - last_offline_packet_received_) <
             base::TimeDelta::FromSeconds(5)) {
           // We can compare this sum with the sum of NCN.OfflineDataRecv.
           UMA_HISTOGRAM_COUNTS_10000(
               "NCN.OfflineDataRecvAny5sBeforeOnline",
               offline_packets_received_);
         }
 
         UMA_HISTOGRAM_MEDIUM_TIMES("NCN.OfflineDataRecvUntilOnline",
                                    last_connection_change_ -
                                        last_offline_packet_received_);
       }
     } else {
       UMA_HISTOGRAM_MEDIUM_TIMES("NCN.OfflineChange",
                                  SinceLast(&last_connection_change_));
     }
+    UMA_HISTOGRAM_MEDIUM_TIMES(
+        "NCN.IPAddressChangeToConnectionTypeChange",
+        last_connection_change_ - last_ip_address_change_);
 
     offline_packets_received_ = 0;
     last_connection_type_ = type;
     polling_interval_ = base::TimeDelta::FromSeconds(1);
   }
 
   // NetworkChangeNotifier::DNSObserver implementation.
   virtual void OnDNSChanged() OVERRIDE {
     UMA_HISTOGRAM_MEDIUM_TIMES("NCN.DNSConfigChange",
                                SinceLast(&last_dns_change_));
   }
 
+  // NetworkChangeNotifier::NetworkChangeObserver implementation.
+  virtual void OnNetworkChanged(
+      NetworkChangeNotifier::ConnectionType type) OVERRIDE {
+    if (type != NetworkChangeNotifier::CONNECTION_NONE) {
+      UMA_HISTOGRAM_MEDIUM_TIMES("NCN.NetworkOnlineChange",
+                                 SinceLast(&last_network_change_));
+    } else {
+      UMA_HISTOGRAM_MEDIUM_TIMES("NCN.NetworkOfflineChange",
+                                 SinceLast(&last_network_change_));
+    }
+  }
+
   // Record histogram data whenever we receive a packet but think we're
   // offline.  Should only be called from the network thread.
   void NotifyDataReceived(const GURL& source) {
     if (last_connection_type_ != NetworkChangeNotifier::CONNECTION_NONE ||
         IsLocalhost(source.host()) ||
         !(source.SchemeIs("http") || source.SchemeIs("https"))) {
       return;
     }
 
     base::TimeTicks current_time = base::TimeTicks::Now();
@@ skipping 23 matching lines @@
   static base::TimeDelta SinceLast(base::TimeTicks *last_time) {
     base::TimeTicks current_time = base::TimeTicks::Now();
     base::TimeDelta delta = current_time - *last_time;
     *last_time = current_time;
     return delta;
   }
 
   base::TimeTicks last_ip_address_change_;
   base::TimeTicks last_connection_change_;
   base::TimeTicks last_dns_change_;
+  base::TimeTicks last_network_change_;
   base::TimeTicks last_offline_packet_received_;
   base::TimeTicks last_polled_connection_;
   // |polling_interval_| is initialized by |OnConnectionTypeChanged| on our
   // first transition to offline and on subsequent transitions.  Once offline,
   // |polling_interval_| doubles as offline data is received and we poll
   // with |NetworkChangeNotifier::GetConnectionType| to verify the connection
   // state.
   base::TimeDelta polling_interval_;
   // |last_connection_type_| is the last value passed to
   // |OnConnectionTypeChanged|.
@@ skipping 20 matching lines @@
   void SetDnsConfig(const DnsConfig& dns_config) {
     base::AutoLock lock(lock_);
     dns_config_ = dns_config;
   }
 
  private:
   mutable base::Lock lock_;
   DnsConfig dns_config_;
 };
 
+NetworkChangeNotifier::NetworkChangeCalculatorParams::
+    NetworkChangeCalculatorParams() {
+}
+
+// Calculates NetworkChange signal from IPAddress and ConnectionType signals.
+class NetworkChangeNotifier::NetworkChangeCalculator
+    : public ConnectionTypeObserver,
+      public IPAddressObserver {
+ public:
+  NetworkChangeCalculator(const NetworkChangeCalculatorParams& params)
+      : params_(params),
+        have_announced_(false),
+        last_announced_connection_type_(CONNECTION_NONE),
+        pending_connection_type_(CONNECTION_NONE) {}
+  void Init() {

[szym, 2012/11/27 22:22:05]

nit: add blank line

+    AddConnectionTypeObserver(this);
+    AddIPAddressObserver(this);

[szym, 2012/11/27 22:22:05]

This makes it so that NetworkChangeCalculator will be called on the UI thread
before anything else is called (on the UI thread) on those changes. Not yet sure
if this matters, but worth keeping in mind.

+  }

[szym, 2012/11/27 22:22:05]

nit: add blank line

+  virtual ~NetworkChangeCalculator() {
+    RemoveConnectionTypeObserver(this);
+    RemoveIPAddressObserver(this);
+  }
+
+  // NetworkChangeNotifier::IPAddressObserver implementation.
+  virtual void OnIPAddressChanged() OVERRIDE {
+    base::TimeDelta delay = last_announced_connection_type_ == CONNECTION_NONE
+        ? params_.ip_address_offline_delay_ : params_.ip_address_online_delay_;
+    // Cancels any previous timer.
+    timer_.Start(FROM_HERE, delay, this, &NetworkChangeCalculator::Notify);
+  }
+
+  // NetworkChangeNotifier::ConnectionTypeObserver implementation.
+  virtual void OnConnectionTypeChanged(ConnectionType type) OVERRIDE {
+    pending_connection_type_ = type;
+    base::TimeDelta delay = last_announced_connection_type_ == CONNECTION_NONE
+        ? params_.connection_type_offline_delay_
+        : params_.connection_type_online_delay_;
+    // Cancels any previous timer.
+    timer_.Start(FROM_HERE, delay, this, &NetworkChangeCalculator::Notify);
+  }
+
+ private:
+  void Notify() {
+    // Don't bother signaling about dead connections.
+    if (have_announced_ &&
+        (last_announced_connection_type_ == CONNECTION_NONE) &&
+        (pending_connection_type_ == CONNECTION_NONE)) {
+      return;
+    }
+    have_announced_ = true;
+    last_announced_connection_type_ = pending_connection_type_;
+    // Immediately before sending out an online signal, send out an offline
+    // signal to perform any destructive actions before constructive actions.
+    if (pending_connection_type_ != CONNECTION_NONE)
+      NetworkChangeNotifier::NotifyObserversOfNetworkChange(CONNECTION_NONE);
+    NetworkChangeNotifier::NotifyObserversOfNetworkChange(
+        pending_connection_type_);
+  }
+
+  const NetworkChangeCalculatorParams params_;
+
+  // Indicates if NotifyObserversOfNetworkChange has been called yet.
+  bool have_announced_;
+  // Last value passed to NotifyObserversOfNetworkChange.
+  ConnectionType last_announced_connection_type_;
+  // Value to pass to NotifyObserversOfNetworkChange when Notify is called.
+  ConnectionType pending_connection_type_;
+  // Used to delay notifications so duplicates can be combined.
+  base::OneShotTimer<NetworkChangeCalculator> timer_;
+};
+
 NetworkChangeNotifier::~NetworkChangeNotifier() {
   DCHECK_EQ(this, g_network_change_notifier);
   g_network_change_notifier = NULL;
 }
 
 // static
 void NetworkChangeNotifier::SetFactory(
     NetworkChangeNotifierFactory* factory) {
   CHECK(!g_network_change_notifier_factory);
   g_network_change_notifier_factory = factory;
@@ skipping 133 matching lines @@
   }
 }
 
 void NetworkChangeNotifier::AddDNSObserver(DNSObserver* observer) {
   if (g_network_change_notifier) {
     g_network_change_notifier->resolver_state_observer_list_->AddObserver(
         observer);
   }
 }
 
+void NetworkChangeNotifier::AddNetworkChangeObserver(
+    NetworkChangeObserver* observer) {
+  if (g_network_change_notifier) {
+    g_network_change_notifier->network_change_observer_list_->AddObserver(
+        observer);
+  }
+}
+
 void NetworkChangeNotifier::RemoveIPAddressObserver(
     IPAddressObserver* observer) {
   if (g_network_change_notifier) {
     g_network_change_notifier->ip_address_observer_list_->RemoveObserver(
         observer);
   }
 }
 
 void NetworkChangeNotifier::RemoveConnectionTypeObserver(
     ConnectionTypeObserver* observer) {
   if (g_network_change_notifier) {
     g_network_change_notifier->connection_type_observer_list_->RemoveObserver(
         observer);
   }
 }
 
 void NetworkChangeNotifier::RemoveDNSObserver(DNSObserver* observer) {
   if (g_network_change_notifier) {
     g_network_change_notifier->resolver_state_observer_list_->RemoveObserver(
         observer);
   }
 }
 
-NetworkChangeNotifier::NetworkChangeNotifier()
+void NetworkChangeNotifier::RemoveNetworkChangeObserver(
+    NetworkChangeObserver* observer) {
+  if (g_network_change_notifier) {
+    g_network_change_notifier->network_change_observer_list_->RemoveObserver(
+        observer);
+  }
+}
+
+NetworkChangeNotifier::NetworkChangeNotifier(
+    const NetworkChangeCalculatorParams& params)
     : ip_address_observer_list_(
         new ObserverListThreadSafe<IPAddressObserver>(
             ObserverListBase<IPAddressObserver>::NOTIFY_EXISTING_ONLY)),
       connection_type_observer_list_(
         new ObserverListThreadSafe<ConnectionTypeObserver>(
             ObserverListBase<ConnectionTypeObserver>::NOTIFY_EXISTING_ONLY)),
       resolver_state_observer_list_(
         new ObserverListThreadSafe<DNSObserver>(
             ObserverListBase<DNSObserver>::NOTIFY_EXISTING_ONLY)),
+      network_change_observer_list_(
+        new ObserverListThreadSafe<NetworkChangeObserver>(
+            ObserverListBase<NetworkChangeObserver>::NOTIFY_EXISTING_ONLY)),
       network_state_(new NetworkState()),
-      histogram_watcher_(new HistogramWatcher()) {
+      histogram_watcher_(new HistogramWatcher()),
+      network_change_calculator_(new NetworkChangeCalculator(params)) {
   DCHECK(!g_network_change_notifier);
   g_network_change_notifier = this;
+  network_change_calculator_->Init();
 }
 
 #if defined(OS_LINUX)
 const internal::AddressTrackerLinux*
 NetworkChangeNotifier::GetAddressTrackerInternal() const {
   return NULL;
 }
 #endif
 
 // static
@@ skipping 21 matching lines @@
 }
 
 void NetworkChangeNotifier::NotifyObserversOfConnectionTypeChange() {
   if (g_network_change_notifier) {
     g_network_change_notifier->connection_type_observer_list_->Notify(
         &ConnectionTypeObserver::OnConnectionTypeChanged,
         GetConnectionType());
   }
 }
 
+void NetworkChangeNotifier::NotifyObserversOfNetworkChange(
+    ConnectionType type) {
+  if (g_network_change_notifier) {
+    g_network_change_notifier->network_change_observer_list_->Notify(
+        &NetworkChangeObserver::OnNetworkChanged,
+        type);
+  }
+}
+
 NetworkChangeNotifier::DisableForTest::DisableForTest()
     : network_change_notifier_(g_network_change_notifier) {
   DCHECK(g_network_change_notifier);
   g_network_change_notifier = NULL;
 }
 
 NetworkChangeNotifier::DisableForTest::~DisableForTest() {
   DCHECK(!g_network_change_notifier);
   g_network_change_notifier = network_change_notifier_;
 }
 
 }  // namespace net