[CrOS Tether] Create the ActiveHost class, which stores metadata related to the current connection …

chromeos/components/tether/active_host.cc

Index: chromeos/components/tether/active_host.cc
diff --git a/chromeos/components/tether/active_host.cc b/chromeos/components/tether/active_host.cc
new file mode 100644
index 0000000000000000000000000000000000000000..c54dcc93469f7e1ade1bd4e8e9f5adc834cf54ca
--- /dev/null
+++ b/chromeos/components/tether/active_host.cc
@@ -0,0 +1,136 @@
+// Copyright 2017 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 "chromeos/components/tether/active_host.h"
+
+#include "base/bind.h"
+#include "base/values.h"
+#include "chromeos/components/tether/pref_names.h"
+#include "chromeos/components/tether/tether_host_fetcher.h"
+#include "components/cryptauth/remote_device.h"
+#include "components/prefs/pref_registry_simple.h"
+#include "components/prefs/pref_service.h"
+#include "components/proximity_auth/logging/logging.h"
+
+namespace chromeos {
+
+namespace tether {
+
+ActiveHost::ActiveHost(TetherHostFetcher* tether_host_fetcher,
+                       PrefService* pref_service)
+    : tether_host_fetcher_(tether_host_fetcher),
+      pref_service_(pref_service),
+      weak_ptr_factory_(this) {}
+
+ActiveHost::~ActiveHost() {}
+
+// static
+void ActiveHost::RegisterPrefs(PrefRegistrySimple* registry) {
+  registry->RegisterIntegerPref(
+      prefs::kActiveHostStatus,
+      static_cast<int>(ActiveHostStatus::DISCONNECTED));
+  registry->RegisterStringPref(prefs::kActiveHostDeviceId, "");
+  registry->RegisterStringPref(prefs::kTetherNetworkSsid, "");
+}
+
+void ActiveHost::SetActiveHostDisconnected() {
+  SetActiveHost(ActiveHostStatus::DISCONNECTED, "" /* active_host_device_id */,
+                "" /* tether_network_ssid */);
+}
+
+void ActiveHost::SetActiveHostConnecting(
+    const std::string& active_host_device_id) {
+  DCHECK(!active_host_device_id.empty());
+
+  SetActiveHost(ActiveHostStatus::CONNECTING, active_host_device_id,
+                "" /* tether_network_ssid */);
+}
+
+void ActiveHost::SetActiveHostConnected(
+    const std::string& active_host_device_id,
+    const std::string& tether_network_ssid) {
+  DCHECK(!active_host_device_id.empty());
+  DCHECK(!tether_network_ssid.empty());
+
+  SetActiveHost(ActiveHostStatus::CONNECTED, active_host_device_id,
+                tether_network_ssid);
+}
+
+void ActiveHost::GetActiveHost(const ActiveHostCallback& active_host_callback) {
+  ActiveHostStatus status = GetActiveHostStatus();
+
+  if (status == ActiveHostStatus::DISCONNECTED) {
+    active_host_callback.Run(status, nullptr, "");
+    return;
+  }
+
+  std::string active_host_device_id = GetActiveHostDeviceId();
+  DCHECK(!active_host_device_id.empty());
+
+  tether_host_fetcher_->FetchTetherHost(
+      active_host_device_id,
+      base::Bind(&ActiveHost::OnTetherHostFetched,
+                 weak_ptr_factory_.GetWeakPtr(), active_host_callback));
+}
+
+ActiveHost::ActiveHostStatus ActiveHost::GetActiveHostStatus() const {
+  return static_cast<ActiveHostStatus>(
+      pref_service_->GetInteger(prefs::kActiveHostStatus));
+}
+
+const std::string ActiveHost::GetActiveHostDeviceId() const {
+  return pref_service_->GetString(prefs::kActiveHostDeviceId);
+}
+
+const std::string ActiveHost::GetTetherNetworkSsid() const {
+  return pref_service_->GetString(prefs::kTetherNetworkSsid);
+}
+
+void ActiveHost::SetActiveHost(ActiveHostStatus active_host_status,
+                               const std::string& active_host_device_id,
+                               const std::string& tether_network_ssid) {
+  pref_service_->Set(prefs::kActiveHostStatus,
+                     base::Value(static_cast<int>(active_host_status)));
+  pref_service_->Set(prefs::kActiveHostDeviceId,
+                     base::Value(active_host_device_id));
+  pref_service_->Set(prefs::kTetherNetworkSsid,
+                     base::Value(tether_network_ssid));
+}
+
+void ActiveHost::OnTetherHostFetched(
+    const ActiveHostCallback& active_host_callback,
+    std::unique_ptr<cryptauth::RemoteDevice> remote_device) {
+  if (GetActiveHostDeviceId().empty() || !remote_device) {
+    DCHECK(GetActiveHostStatus() == ActiveHostStatus::DISCONNECTED);
+    DCHECK(GetTetherNetworkSsid().empty());
+
+    // If the active host became disconnected while the tether host was being
+    // fetched, forward this information to the callback.
+    active_host_callback.Run(ActiveHostStatus::DISCONNECTED, nullptr, "");
+    return;
+  }
+
+  if (GetActiveHostDeviceId() != remote_device->GetDeviceId()) {
+    // If the active host has changed while the tether host was being fetched,
+    // perform the fetch again.
+    GetActiveHost(active_host_callback);
+    return;
+  }
+
+  if (GetActiveHostStatus() == ActiveHostStatus::CONNECTING) {
+    DCHECK(GetTetherNetworkSsid().empty());

[Ryan Hansberry, 2017/03/09 17:20:48]

It's possible that the network_id is known (non-empty) but the Wi-Fi network is
still connecting (for example, we recently received the ConnectTetheringResponse
and have configured the Wi-Fi network, but are waiting to fully connect). tldr;
this check is incorrect.

[Kyle Horimoto, 2017/03/09 18:42:00]

As discussed offline, this is an implementation detail of the "connecting"
state. Leaving as is.

+    active_host_callback.Run(ActiveHostStatus::CONNECTING,
+                             std::move(remote_device), "");

[Ryan Hansberry, 2017/03/09 17:20:48]

add a /* argument comment */

[Kyle Horimoto, 2017/03/09 18:42:00]

Done.

+    return;
+  }
+
+  DCHECK(GetActiveHostStatus() == ActiveHostStatus::CONNECTED);
+  DCHECK(!GetTetherNetworkSsid().empty());
+  active_host_callback.Run(ActiveHostStatus::CONNECTED,
+                           std::move(remote_device), GetTetherNetworkSsid());
+}
+
+}  // namespace tether
+
+}  // namespace chromeos