[CrOS Tether] Sort Tether network lists.

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 e95ba4f933e7f194fb4f7a195450912dac57e161..c0e8f2925c3f8af3ee919a4e3058812098198af7 100644
--- a/chromeos/network/network_state_handler.cc
+++ b/chromeos/network/network_state_handler.cc
@@ -67,6 +67,26 @@ std::string ValueAsString(const base::Value& value) {
   return vstr.empty() ? "''" : vstr;
 }
 
+void EnsureActiveNetworksInFrontOfList(
+    NetworkStateHandler::NetworkStateList* list) {
+  size_t last_active_network_index = -1;

[stevenjb, 2017/06/22 00:25:19]

Don't use size_t with negative values, it's generally unsigned.

You can use std::numeric_limits<size_t>::max() (include <limits>), but then will
need to change the logic... see below...

[Kyle Horimoto, 2017/06/22 02:08:01]

Acknowledged.

+  for (size_t i = 0; i < list->size(); ++i) {
+    const NetworkState* network = list->at(i);
+    if (network->IsConnectingState() || network->IsConnectedState()) {

[stevenjb, 2017/06/22 00:25:19]

I started to make some suggestions here, but this is a) confusing and b) not
super efficient (inserting into a vector is slow), see alternate suggestion
below.

[Kyle Horimoto, 2017/06/22 02:08:01]

Acknowledged.

+      // A new active network has been found in the list.
+      last_active_network_index++;
+
+      if (i != last_active_network_index) {
+        // If this is an active network that is not in the correct order
+        // (i.e., it is listed after non-active networks), move it to the
+        // correct spot.
+        list->erase(list->begin() + i);
+        list->insert(list->begin() + last_active_network_index, network);
+      }
+    }
+  }
+}
+
 }  // namespace
 
 const char NetworkStateHandler::kDefaultCheckPortalList[] =
@@ -428,15 +448,9 @@ void NetworkStateHandler::GetNetworkListByType(const NetworkTypePattern& type,
 
   int count = list->size();
 
-  if (type.Equals(NetworkTypePattern::Tether()) ||
-      (limit != 0 && count >= limit)) {
-    // 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;
-  }
-
-  for (auto iter = network_list_.begin(); iter != network_list_.end(); ++iter) {
+  // Only add more networks if the limit has not yet been reached.
+  for (auto iter = network_list_.begin();
+       iter != network_list_.end() && (limit == 0 || count < limit); ++iter) {

[stevenjb, 2017/06/22 00:25:19]

Now that we've changed the logic, this is probably more clear without |count|,
just use list->size() (which arguably would have been more clear before also).

[Kyle Horimoto, 2017/06/22 02:08:01]

Done.

     const NetworkState* network = (*iter)->AsNetworkState();
     DCHECK(network);
     if (!network->update_received() || !network->Matches(type))
@@ -445,14 +459,29 @@ void NetworkStateHandler::GetNetworkListByType(const NetworkTypePattern& type,
       continue;
     if (visible_only && !network->visible())
       continue;
+    if (network->type() == shill::kTypeWifi &&
+        !network->tether_guid().empty()) {
+      // Wi-Fi networks which are actually underlying Wi-Fi hotspots for a
+      // Tether network should not be returned since they should only be shown
+      // to the user as Tether networks.
+      continue;
+    }

[stevenjb, 2017/06/22 00:25:19]

Move all of the above logic into helper method (e.g.
IncludeNetworkInList(network, configured_only, visible_only)), then...

[Kyle Horimoto, 2017/06/22 02:08:01]

Done.

     if (network->type() == shill::kTypeEthernet) {
       // Ethernet networks should always be in front.
       list->insert(list->begin(), network);
     } else {
       list->push_back(network);
     }

[stevenjb, 2017/06/22 00:25:19]

break if this is not an active network (note: Ethernet will *always* be active)

[Kyle Horimoto, 2017/06/22 02:08:01]

Done.

-    if (limit > 0 && ++count >= limit)
-      break;
+    count++;
+  }
+
+  if (type.MatchesPattern(NetworkTypePattern::Tether())) {
+    // Tether networks were added to |list| above before non-Tether networks.
+    // Thus, if |type| includes Tether networks, it is possible that |list|
+    // contains some non-active Tether networks before some active (i.e.,
+    // connecting or connected) non-Tether networks. Active networks should
+    // always be listed first, so adjust the list accordingly.
+    EnsureActiveNetworksInFrontOfList(list);

[stevenjb, 2017/06/22 00:25:19]

Append GetTetherNetworkList(limit, list, active=false) here

Then continue iterating network_list and append inactive networks.

So the code will look like:

  GetTetherNetworkList(limit, list, true /* active */);

  for ((auto iter = network_list_.begin();
       iter != network_list_.end() && (limit == 0 || list->size() < limit);
       ++iter) {
    const NetworkState* network = (*iter)->AsNetworkState();
    if (!IncludeNetworkInList(network, configured_only, visible_only)
      continue;
    if (!IsActiveNetwork(network))
      break;
    if (network->type() == shill::kTypeEthernet) {
      // Ethernet networks should always be in front.
      list->insert(list->begin(), network);
    } else {
      list->push_back(network);
    }
  }

  GetTetherNetworkList(limit, list, false /* active */);

  for ((auto iter = network_list_.begin();
       iter != network_list_.end() && (limit == 0 || list->size() < limit);
       ++iter) {
    const NetworkState* network = (*iter)->AsNetworkState();
    if (!IncludeNetworkInList(network, configured_only, visible_only)
      continue;
    list->push_back(network);
  }

The advantage to this approach is that it is immediately clear that the order
is:
Active Tether
Active Shill networks
Inactive Tether
Inactive Shill networks

[Kyle Horimoto, 2017/06/22 02:08:01]

Done.

   }
 }
 
@@ -538,6 +567,8 @@ void NetworkStateHandler::AddTetherNetworkState(const std::string& guid,
   tether_network_state->set_signal_strength(signal_strength);
 
   tether_network_list_.push_back(std::move(tether_network_state));
+  network_list_sorted_ = false;
+
   NotifyNetworkListChanged();
 }
 
@@ -562,6 +593,7 @@ bool NetworkStateHandler::UpdateTetherNetworkProperties(
   tether_network_state->set_carrier(carrier);
   tether_network_state->set_battery_percentage(battery_percentage);
   tether_network_state->set_signal_strength(signal_strength);
+  network_list_sorted_ = false;
 
   NotifyNetworkPropertiesUpdated(tether_network_state);
   return true;
@@ -581,6 +613,7 @@ bool NetworkStateHandler::SetTetherNetworkHasConnectedToHost(
   }
 
   tether_network_state->set_tether_has_connected_to_host(true);
+  network_list_sorted_ = false;
 
   NotifyNetworkPropertiesUpdated(tether_network_state);
   return true;
@@ -634,6 +667,7 @@ bool NetworkStateHandler::DisassociateTetherNetworkStateFromWifiNetwork(
 
   wifi_network_state->set_tether_guid(std::string());
   tether_network_state->set_tether_guid(std::string());
+  network_list_sorted_ = false;
 
   NotifyNetworkPropertiesUpdated(wifi_network_state);
   NotifyNetworkPropertiesUpdated(tether_network_state);
@@ -681,6 +715,7 @@ bool NetworkStateHandler::AssociateTetherNetworkStateWithWifiNetwork(
 
   tether_network_state->set_tether_guid(wifi_network_guid);
   wifi_network_state->set_tether_guid(tether_network_guid);
+  network_list_sorted_ = false;
 
   NotifyNetworkPropertiesUpdated(wifi_network_state);
   NotifyNetworkPropertiesUpdated(tether_network_state);
@@ -739,8 +774,9 @@ void NetworkStateHandler::SetTetherNetworkStateConnectionState(
 
   std::string prev_connection_state = tether_network_state->connection_state();
   tether_network_state->set_connection_state(connection_state);
-  DCHECK(!tether_network_state->is_captive_portal());
+  network_list_sorted_ = false;
 
+  DCHECK(!tether_network_state->is_captive_portal());
   if (ConnectionStateChanged(tether_network_state, prev_connection_state,
                              false /* prev_is_captive_portal */)) {
     NET_LOG(EVENT) << "Changing connection state for Tether network with GUID "
@@ -1207,8 +1243,10 @@ void NetworkStateHandler::ManagedStateListChanged(
   }
 }
 
-// TODO(khorimoto): Add sorting for the Tether network list as well.
 void NetworkStateHandler::SortNetworkList() {
+  if (tether_sort_delegate_)
+    tether_sort_delegate_->SortTetherNetworkList(&tether_network_list_);
+
   // Note: usually active networks will precede inactive networks, however
   // this may briefly be untrue during state transitions (e.g. a network may
   // transition to idle before the list is updated).