[GCM] Add heartbeat manager and reconnection logic due to heartbeat failure

google_apis/gcm/engine/heartbeat_manager.cc

+// Copyright 2013 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 "google_apis/gcm/engine/heartbeat_manager.h"
+
+#include "google_apis/gcm/protocol/mcs.pb.h"
+#include "net/base/network_change_notifier.h"
+
+namespace gcm {
+
+namespace {
+// The default heartbeat when on a mobile or unknown network .
+const int64 kCellHeartbeatDefaultMs = 1000 * 60 * 15;  // 15 minutes.

[fgorski, 2013/12/19 23:55:13]

Cell should be 28, wifi 15. 

[Nicolas Zea, 2013/12/20 22:52:56]

Good catch, done.

+// The default heartbeat when on WiFi (also used for ethernet).
+const int64 kWifiHeartbeatDefaultMs = 1000 * 60 * 28;  // 28 minutes.
+// The default heartbeat ack interval.
+const int64 kHeartbeatAckDefaultMs = 1000 * 60 * 1;  // 1 minute.
+}  // namespace
+
+HeartbeatManager::HeartbeatManager()
+   : waiting_for_ack_(false),
+     server_interval_ms_(0),
+     heartbeat_timer_(true  /* retain user task */, false  /* not repeating */),
+     weak_ptr_factory_(this) {}
+HeartbeatManager::~HeartbeatManager() {}
+
+void HeartbeatManager::Start(
+    const base::Closure& send_heartbeat_callback,
+    const base::Closure& trigger_reconnect_callback) {

[fgorski, 2013/12/19 23:55:13]

DCHECK both callbacks. You are doing that in OnHeartbeatAcked, you can do it
much earlier here.

[Nicolas Zea, 2013/12/20 22:52:56]

Done.

+  send_heartbeat_callback_ = send_heartbeat_callback;
+  trigger_reconnect_callback_ = trigger_reconnect_callback;
+
+  // Kicks off the timer.
+  waiting_for_ack_ = false;
+  RestartTimer();
+}
+
+void HeartbeatManager::Stop() {
+  heartbeat_timer_.Stop();
+  waiting_for_ack_ = false;
+}
+
+void HeartbeatManager::OnHeartbeatAcked() {
+  if (!heartbeat_timer_.IsRunning())
+    return;
+
+  DCHECK(!send_heartbeat_callback_.is_null());
+  DCHECK(!trigger_reconnect_callback_.is_null());
+  waiting_for_ack_ = false;
+  RestartTimer();
+}
+
+void HeartbeatManager::UpdateHeartbeatConfig(
+    const mcs_proto::HeartbeatConfig& config) {
+  if (!config.IsInitialized() ||
+      !config.has_interval_ms() ||
+      config.interval_ms() <= 0) {
+    return;
+  }
+  DVLOG(1) << "Updating heartbeat interval to " << config.interval_ms();
+  server_interval_ms_ = config.interval_ms();
+  heartbeat_interval_ = base::TimeDelta::FromMilliseconds(server_interval_ms_);
+}
+
+base::TimeTicks HeartbeatManager::GetNextHeartbeatTime() const {
+  if (heartbeat_timer_.IsRunning())
+    return heartbeat_timer_.desired_run_time();
+  else
+    return base::TimeTicks();

[fgorski, 2013/12/19 23:55:13]

Based on the documentation of the method it can be interpreted as HB Ack is due,
even though the time is not running. Can that backfire?

[Nicolas Zea, 2013/12/20 22:52:56]

Updated documentation.

+}
+
+void HeartbeatManager::OnHeartbeatTriggered() {
+  if (waiting_for_ack_) {
+    LOG(WARNING) << "Lost connection to MCS, reconnecting.";
+    Stop();
+    trigger_reconnect_callback_.Run();
+    return;
+  }
+
+  waiting_for_ack_ = true;
+  RestartTimer();
+  send_heartbeat_callback_.Run();
+}
+
+void HeartbeatManager::RestartTimer() {
+  if (!waiting_for_ack_) {
+    // Recalculate the timer interval based network type.
+    if (server_interval_ms_ != 0) {
+      // If a server interval is set, it overrides any local one.
+      heartbeat_interval_ =
+          base::TimeDelta::FromMilliseconds(server_interval_ms_);
+    } else if (net::NetworkChangeNotifier::GetConnectionType() ==
+                   net::NetworkChangeNotifier::CONNECTION_WIFI ||
+               net::NetworkChangeNotifier::GetConnectionType() ==
+                   net::NetworkChangeNotifier::CONNECTION_ETHERNET) {
+      heartbeat_interval_ =
+          base::TimeDelta::FromMilliseconds(kWifiHeartbeatDefaultMs);
+    } else {
+      // For unknown connections, use the shorter cellular heartbeat interval.

[fgorski, 2013/12/19 23:55:13]

longer :)

[Nicolas Zea, 2013/12/20 22:52:56]

Done.

+      heartbeat_interval_ =
+          base::TimeDelta::FromMilliseconds(kCellHeartbeatDefaultMs);
+    }
+    DVLOG(1) << "Sending next heartbeat in "
+             << heartbeat_interval_.InSeconds() << " seconds.";
+    heartbeat_timer_.Start(FROM_HERE,
+                           heartbeat_interval_,
+                           base::Bind(&HeartbeatManager::OnHeartbeatTriggered,
+                                      weak_ptr_factory_.GetWeakPtr()));
+  } else {
+    heartbeat_interval_ =
+        base::TimeDelta::FromMilliseconds(kHeartbeatAckDefaultMs);
+    DVLOG(1) << "Resetting timer for ack with "
+             << heartbeat_interval_.InSeconds() << " second interval.";
+    heartbeat_timer_.Reset();
+  }
+}
+
+}  // namespace gcm