[CrOS Tether] Create KeepAliveScheduler, a class which schedules keep-alive tickles to be sent to a…

chromeos/components/tether/keep_alive_scheduler.cc

+// 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/keep_alive_scheduler.h"
+
+#include "base/bind.h"
+
+namespace chromeos {
+
+namespace tether {
+
+// static
+const uint32_t KeepAliveScheduler::kKeepAliveIntervalMinutes = 4;
+
+KeepAliveScheduler::KeepAliveScheduler(ActiveHost* active_host,
+                                       BleConnectionManager* connection_manager)
+    : KeepAliveScheduler(active_host,
+                         connection_manager,
+                         base::MakeUnique<base::RepeatingTimer>()) {}
+
+KeepAliveScheduler::KeepAliveScheduler(ActiveHost* active_host,
+                                       BleConnectionManager* connection_manager,
+                                       std::unique_ptr<base::Timer> timer)

[Jeremy Klein, 2017/03/10 23:58:08]

Should this also just be a RepeatingTimer? I know it doesn't matter in practice,
but think this class isn't really valid with a OneShotTimer.

[Kyle Horimoto, 2017/03/11 00:03:09]

Yeah, but unfortunately MockTimer doesn't derive from RepeatingTimer. Do you
have any suggestions for how to make this work?

[Jeremy Klein, 2017/03/11 00:09:18]

Gah, bummer :-/. Nah, not really. It's not a huge deal.

+    : active_host_(active_host),
+      connection_manager_(connection_manager),
+      timer_(std::move(timer)),
+      weak_ptr_factory_(this) {
+  if (active_host_) {

[Jeremy Klein, 2017/03/10 23:58:08]

When would active_host_ be null here? Is that a legit use case?

[Kyle Horimoto, 2017/03/11 00:03:09]

Done.

+    active_host_->AddObserver(this);
+  }
+}
+
+KeepAliveScheduler::~KeepAliveScheduler() {
+  if (active_host_) {
+    active_host_->RemoveObserver(this);
+  }
+}
+
+void KeepAliveScheduler::OnActiveHostChanged(
+    ActiveHost::ActiveHostStatus active_host_status,
+    std::unique_ptr<cryptauth::RemoteDevice> active_host_device,
+    const std::string& wifi_network_id) {
+  if (active_host_status == ActiveHost::ActiveHostStatus::DISCONNECTED) {
+    DCHECK(!active_host_device);
+    DCHECK(wifi_network_id.empty());
+
+    keep_alive_operation_.reset();
+    active_host_device_.reset();
+    timer_->Stop();
+    return;
+  }
+
+  if (active_host_status == ActiveHost::ActiveHostStatus::CONNECTED) {
+    DCHECK(active_host_device);
+    active_host_device_ = std::move(active_host_device);
+    timer_->Start(FROM_HERE,
+                  base::TimeDelta::FromMinutes(kKeepAliveIntervalMinutes),
+                  base::Bind(&KeepAliveScheduler::SendKeepAliveTickle,
+                             weak_ptr_factory_.GetWeakPtr()));
+    SendKeepAliveTickle();
+  }
+}
+
+void KeepAliveScheduler::OnOperationFinished() {
+  keep_alive_operation_->RemoveObserver(this);
+  keep_alive_operation_.reset();
+}
+
+void KeepAliveScheduler::SendKeepAliveTickle() {
+  DCHECK(active_host_device_);
+
+  keep_alive_operation_ = KeepAliveOperation::Factory::NewInstance(
+      *active_host_device_, connection_manager_);
+  keep_alive_operation_->AddObserver(this);
+  keep_alive_operation_->Initialize();
+}
+
+}  // namespace tether
+
+}  // namespace chromeos