[CrOS Tether] Add the notion of a tether DeviceState.

chromeos/network/network_state_handler.cc

Index: chromeos/network/network_state_handler.cc
diff --git a/chromeos/network/network_state_handler.cc b/chromeos/network/network_state_handler.cc
index d1fe75c1ebad0dac0bd732bcc7960573fac3f965..8f4265d1a1c4f5624147157fbae68e8d04f18ceb 100644
--- a/chromeos/network/network_state_handler.cc
+++ b/chromeos/network/network_state_handler.cc
@@ -126,9 +126,7 @@ NetworkStateHandler::TechnologyState NetworkStateHandler::GetTechnologyState(
   std::string technology = GetTechnologyForType(type);
 
   if (technology == kTypeTether) {
-    bool is_tether_enabled = base::CommandLine::ForCurrentProcess()->HasSwitch(
-        chromeos::switches::kEnableTether);
-    return is_tether_enabled ? TECHNOLOGY_ENABLED : TECHNOLOGY_UNAVAILABLE;
+    return tether_technology_state_;
   }
 
   TechnologyState state;
@@ -154,6 +152,14 @@ void NetworkStateHandler::SetTechnologyEnabled(
     const network_handler::ErrorCallback& error_callback) {
   std::vector<std::string> technologies = GetTechnologiesForType(type);
   for (const std::string& technology : technologies) {
+    if (technology == kTypeTether) {
+      // Tether does not exist in Shill, so set |tether_technology_state_| and
+      // skip the below interactions with |shill_property_handler_|.
+      tether_technology_state_ =
+          enabled ? TECHNOLOGY_ENABLED : TECHNOLOGY_AVAILABLE;

[stevenjb, 2017/04/20 16:49:41]

We need to ensure that this transition is valid:
if (tether_technology_state_ != avaialble or enabled) trigger error callback;
else set tether_technology_state_

[Kyle Horimoto, 2017/04/20 19:38:46]

Done.

+      continue;
+    }
+
     if (!shill_property_handler_->IsTechnologyAvailable(technology))
       continue;
     NET_LOG_USER("SetTechnologyEnabled",
@@ -165,11 +171,53 @@ void NetworkStateHandler::SetTechnologyEnabled(
   NotifyDeviceListChanged();
 }
 
+void NetworkStateHandler::SetTetherTechnologyState(
+    TechnologyState technology_state) {
+  if (tether_technology_state_ == technology_state)
+    return;
+
+  tether_technology_state_ = technology_state;

[stevenjb, 2017/04/20 18:13:45]

So, to go with my comments in UpdateManagedList(), we should probably add a
helper, EnsureTetherDeviceState(), and call that here and at the top of
SetTetherScanState.

Also, EnsureTetherDeviceState() should only add a device if the technology state
is not unavailable, and should remove it if the technology becomes unavailable.
i.e. there should not be a DeviceState entry when tether is not available.

[Kyle Horimoto, 2017/04/20 19:38:46]

Done.

+
+  // Signal Device/Technology state changed.
+  NotifyDeviceListChanged();
+}
+
+void NetworkStateHandler::SetTetherScanState(bool is_scanning) {
+  DeviceState* tether_device_state =
+      GetModifiableDeviceState(kTetherDevicePath);
+  DCHECK(tether_device_state);
+
+  bool was_scanning = tether_device_state->scanning();
+  tether_device_state->set_scanning(is_scanning);
+
+  if (was_scanning && !is_scanning) {
+    // If a scan was in progress but has completed, notify observers.
+    NotifyScanCompleted(tether_device_state);
+  }
+}
+
 void NetworkStateHandler::SetProhibitedTechnologies(
     const std::vector<std::string>& prohibited_technologies,
     const network_handler::ErrorCallback& error_callback) {
-  shill_property_handler_->SetProhibitedTechnologies(prohibited_technologies,
-                                                     error_callback);
+  // Make a copy of |prohibited_technologies| since the list may be edited
+  // within this function.
+  std::vector<std::string> prohibited_technologies_copy =
+      prohibited_technologies;
+
+  for (auto it = prohibited_technologies_copy.begin();
+       it < prohibited_technologies_copy.end(); ++it) {
+    if (*it == kTypeTether) {
+      // If Tether networks are prohibited, set |tether_technology_state_| and
+      // remove |kTypeTether| from the list before passing it to
+      // |shill_property_handler_| below. Shill does not have a concept of
+      // Tether networks, so it cannot prohibit that technology type.
+      tether_technology_state_ = TECHNOLOGY_PROHIBITED;
+      it = prohibited_technologies_copy.erase(it);
+    }
+  }
+
+  shill_property_handler_->SetProhibitedTechnologies(
+      prohibited_technologies_copy, error_callback);
   // Signal Device/Technology state changed.
   NotifyDeviceListChanged();
 }
@@ -300,7 +348,7 @@ const NetworkState* NetworkStateHandler::FirstNetworkByType(
   if (!network_list_sorted_)
     SortNetworkList();  // Sort to ensure visible networks are listed first.
 
-  // If |type| matches tether networks and at least one tether network is
+  // If |type| matches Tether networks and at least one Tether network is
   // present, return the first network (since it has been sorted already).
   if (type.MatchesPattern(NetworkTypePattern::Tether()) &&
       !tether_network_list_.empty()) {
@@ -323,9 +371,14 @@ const NetworkState* NetworkStateHandler::FirstNetworkByType(
 std::string NetworkStateHandler::FormattedHardwareAddressForType(
     const NetworkTypePattern& type) const {
   const NetworkState* network = ConnectedNetworkByType(type);
+  if (network && network->type() == kTypeTether) {
+    // If this is a Tether network, get the MAC address corresponding to that
+    // network instead.
+    network = GetNetworkStateFromGuid(network->tether_guid());
+  }
   const DeviceState* device = network ? GetDeviceState(network->device_path())
                                       : GetDeviceStateByType(type);
-  if (!device)
+  if (!device || device->mac_address().empty())
     return std::string();
   return network_util::FormattedMacAddress(device->mac_address());
 }
@@ -361,7 +414,7 @@ void NetworkStateHandler::GetNetworkListByType(const NetworkTypePattern& type,
 
   if (type.Equals(NetworkTypePattern::Tether()) ||
       (limit != 0 && count >= limit)) {
-    // If only searching for tether networks, there is no need to continue
+    // If only searching for Tether networks, there is no need to continue
     // searching through other network types; likewise, if the limit has already
     // been reached, there is no need to continue searching.
     return;
@@ -431,6 +484,7 @@ void NetworkStateHandler::AddTetherNetworkState(const std::string& guid,
   DCHECK(!guid.empty());
   DCHECK(battery_percentage >= 0 && battery_percentage <= 100);
   DCHECK(signal_strength >= 0 && signal_strength <= 100);
+  DCHECK(tether_technology_state_ == TECHNOLOGY_ENABLED);

[stevenjb, 2017/04/20 16:49:41]

This probably shouldn't be a DCHECK. I can imagine a situation where one part of
the UI posts a task to add a network state (e.g. from JS) while another part of
the code (e.g. policy) disables tether. Instead we should just log an error and
return.

[Kyle Horimoto, 2017/04/20 19:38:46]

Done.

 
   // If the network already exists, do nothing.
   if (GetNetworkStateFromGuid(guid)) {
@@ -463,6 +517,8 @@ bool NetworkStateHandler::UpdateTetherNetworkProperties(
     const std::string& carrier,
     int battery_percentage,
     int signal_strength) {
+  DCHECK(tether_technology_state_ == TECHNOLOGY_ENABLED);

[stevenjb, 2017/04/20 16:49:41]

ditto

[Kyle Horimoto, 2017/04/20 19:38:46]

Done.

+
   NetworkState* tether_network_state = GetModifiableNetworkStateFromGuid(guid);
   if (!tether_network_state)
     return false;
@@ -494,6 +550,8 @@ void NetworkStateHandler::RemoveTetherNetworkState(const std::string& guid) {
 bool NetworkStateHandler::AssociateTetherNetworkStateWithWifiNetwork(
     const std::string& tether_network_guid,
     const std::string& wifi_network_guid) {
+  DCHECK(tether_technology_state_ == TECHNOLOGY_ENABLED);

[stevenjb, 2017/04/20 16:49:41]

ditto

[Kyle Horimoto, 2017/04/20 19:38:46]

Done.

+
   NetworkState* tether_network =
       GetModifiableNetworkStateFromGuid(tether_network_guid);
   if (!tether_network) {
@@ -525,14 +583,14 @@ bool NetworkStateHandler::AssociateTetherNetworkStateWithWifiNetwork(
 
 void NetworkStateHandler::SetTetherNetworkStateDisconnected(
     const std::string& guid) {
-  // TODO(khorimoto): Remove the tether network as the default network, and
+  // TODO(khorimoto): Remove the Tether network as the default network, and
   // send a connection status change.
   SetTetherNetworkStateConnectionState(guid, shill::kStateDisconnect);
 }
 
 void NetworkStateHandler::SetTetherNetworkStateConnecting(
     const std::string& guid) {
-  // TODO(khorimoto): Set the tether network as the default network, and send
+  // TODO(khorimoto): Set the Tether network as the default network, and send
   // a connection status change.
   SetTetherNetworkStateConnectionState(guid, shill::kStateConfiguration);
 }
@@ -693,6 +751,17 @@ void NetworkStateHandler::UpdateManagedList(ManagedState::ManagedType type,
   ManagedStateList* managed_list = GetManagedList(type);
   NET_LOG_DEBUG("UpdateManagedList: " + ManagedState::TypeToString(type),
                 base::StringPrintf("%" PRIuS, entries.GetSize()));
+
+  // Create a copy of |entries| since it may be edited below.
+  base::ListValue entries_copy(entries);
+  if (type == ManagedState::ManagedType::MANAGED_TYPE_DEVICE) {
+    // If a device list update is received from Shill, the list supplied will
+    // never contain an entry for Tether networks since Shill does not recognize
+    // Tether networks as a device type. Before processing the list, add an
+    // entry for the tether device type with the constant tether device path.
+    entries_copy.Append(base::MakeUnique<base::Value>(kTetherDevicePath));
+  }

[stevenjb, 2017/04/20 16:49:41]

This seems unnecessary, and placing the code at 790 inside the loop seems
awkward.

Instead, at line 807, managed_map should still contain a tether device if there
is one. At that point we should move it to managed_list and call
set_update_received/requested.

[Kyle Horimoto, 2017/04/20 19:38:46]

Done.

+
   // Create a map of existing entries. Assumes all entries in |managed_list|
   // are unique.
   std::map<std::string, std::unique_ptr<ManagedState>> managed_map;
@@ -705,7 +774,7 @@ void NetworkStateHandler::UpdateManagedList(ManagedState::ManagedType type,
   managed_list->clear();
   // Updates managed_list and request updates for new entries.
   std::set<std::string> list_entries;
-  for (auto& iter : entries) {
+  for (auto& iter : entries_copy) {
     std::string path;
     iter.GetAsString(&path);
     if (path.empty() || path == shill::kFlimflamServicePath) {
@@ -718,7 +787,17 @@ void NetworkStateHandler::UpdateManagedList(ManagedState::ManagedType type,
         NET_LOG_ERROR("Duplicate entry in list", path);
         continue;
       }
-      managed_list->push_back(ManagedState::Create(type, path));
+      std::unique_ptr<ManagedState> state = ManagedState::Create(type, path);
+      if (type == ManagedState::ManagedType::MANAGED_TYPE_DEVICE &&
+          path == kTetherDevicePath) {
+        // If adding the tether DeviceState, set appropriate properties since
+        // it will never receive a properties update from Shill.
+        state->set_update_received();
+        state->set_update_requested(false);
+        state->set_name(kTetherDeviceName);
+        state->set_type(kTypeTether);
+      }
+      managed_list->push_back(std::move(state));
     } else {
       managed_list->push_back(std::move(found->second));
       managed_map.erase(found);
@@ -971,7 +1050,7 @@ void NetworkStateHandler::ManagedStateListChanged(
   }
 }
 
-// TODO(khorimoto): Add sorting for the tether network list as well.
+// TODO(khorimoto): Add sorting for the Tether network list as well.
 void NetworkStateHandler::SortNetworkList() {
   // Note: usually active networks will precede inactive networks, however
   // this may briefly be untrue during state transitions (e.g. a network may
@@ -1275,6 +1354,8 @@ std::vector<std::string> NetworkStateHandler::GetTechnologiesForType(
     technologies.emplace_back(shill::kTypeBluetooth);
   if (type.MatchesType(shill::kTypeVPN))
     technologies.emplace_back(shill::kTypeVPN);
+  if (type.MatchesType(kTypeTether))
+    technologies.emplace_back(kTypeTether);
 
   CHECK_GT(technologies.size(), 0ul);
   return technologies;