Add basic daily active use logging.

src/platform/metrics/metrics_daemon.h

Index: src/platform/metrics/metrics_daemon.h
diff --git a/src/platform/metrics/metrics_daemon.h b/src/platform/metrics/metrics_daemon.h
index 23f0eb25fd804db5c9aa575efb872923e219dd61..99f76d087198f3e653893d8f42d72fb4ac83db80 100644
--- a/src/platform/metrics/metrics_daemon.h
+++ b/src/platform/metrics/metrics_daemon.h
@@ -6,16 +6,23 @@
 #define METRICS_DAEMON_H_
 
 #include <dbus/dbus.h>
+#include <glib.h>
 #include <time.h>
 
 class MetricsDaemon {
 
  public:
   MetricsDaemon()
-      : testing_(false),
-        network_state_(kUnknownNetworkState),
-        network_state_changed_(0),
-        power_state_(kUnknownPowerState) {}
+      : network_state_(kUnknownNetworkState),
+        network_state_last_(0),
+        power_state_(kUnknownPowerState),
+        screensaver_state_(kUnknownScreenSaverState),
+        session_state_(kUnknownSessionState),
+        user_active_(false),
+        user_active_last_(0),
+        daily_use_day_last_(0),
+        usemon_interval_(0),
+        usemon_source_(NULL) {}
   ~MetricsDaemon() {}
 
   // Does all the work. If |run_as_daemon| is true, daemonizes by
@@ -40,6 +47,45 @@ class MetricsDaemon {
     kNumberPowerStates
   };
 
+  // The screen-saver states (see screensaver_states.h).
+  enum ScreenSaverState {
+    kUnknownScreenSaverState = -1, // Initial/unknown screen-saver state.
+#define STATE(name, capname) kScreenSaverState ## capname,
+#include "screensaver_states.h"
+    kNumberScreenSaverStates
+  };
+
+  // The user session states (see session_states.h).
+  enum SessionState {
+    kUnknownSessionState = -1, // Initial/unknown user session state.
+#define STATE(name, capname) kSessionState ## capname,
+#include "session_states.h"
+    kNumberSessionStates
+  };
+
+  // Data record for aggregating daily usage.
+  class UseRecord {
+   public:
+    UseRecord() : day_(0), seconds_(0) {}
+    int day_;
+    int seconds_;
+  };
+
+  // D-Bus message match strings.
+  static const char* kDBusMatches_[];
+
+  // Array of network states.
+  static const char* kNetworkStates_[kNumberNetworkStates];
+
+  // Array of power states.
+  static const char* kPowerStates_[kNumberPowerStates];
+
+  // Array of screen-saver states.
+  static const char* kScreenSaverStates_[kNumberScreenSaverStates];
+
+  // Array of user session states.
+  static const char* kSessionStates_[kNumberSessionStates];
+
   // Initializes.
   void Init(bool testing);
 
@@ -52,36 +98,103 @@ class MetricsDaemon {
                                          void* user_data);
 
   // Processes network state change.
-  void NetStateChanged(const char* state_name);
+  void NetStateChanged(const char* state_name, time_t now);
 
   // Given the state name, returns the state id.
   NetworkState LookupNetworkState(const char* state_name);
 
   // Processes power state change.
-  void PowerStateChanged(const char* state_name);
+  void PowerStateChanged(const char* state_name, time_t now);
 
   // Given the state name, returns the state id.
   PowerState LookupPowerState(const char* state_name);
 
+  // Processes screen-saver state change.
+  void ScreenSaverStateChanged(const char* state_name, time_t now);
+
+  // Given the state name, returns the state id.
+  ScreenSaverState LookupScreenSaverState(const char* state_name);
+
+  // Processes user session state change.
+  void SessionStateChanged(const char* state_name, time_t now);
+
+  // Given the state name, returns the state id.
+  SessionState LookupSessionState(const char* state_name);
+
+  // Updates the user-active state to |active| and logs the usage data
+  // since the last update. If the user has just become active,
+  // reschedule the daily use monitor for more frequent updates --
+  // this is followed by an exponential back-off (see UseMonitor).
+  void SetUserActiveState(bool active, time_t now);
+
+  // Updates the daily usage file, if necessary, by adding |seconds|
+  // of active use to the |day| since Epoch. If there's usage data for
+  // day in the past in the usage file, that data is sent to UMA and
+  // removed from the file. If there's already usage data for |day| in
+  // the usage file, the |seconds| are accumulated.
+  void LogDailyUseRecord(int day, int seconds);
+
+  // Callbacks for the daily use monitor. The daily use monitor uses
+  // LogDailyUseRecord to aggregate current usage data and send it to
+  // UMA, if necessary. It also reschedules itself using an
+  // exponentially bigger interval (up to a certain maximum) -- so
+  // usage is monitored less frequently with longer active use.
+  static gboolean UseMonitorStatic(gpointer data);
+  bool UseMonitor();
+
+  // Schedules or reschedules a daily use monitor for |interval|
+  // seconds from now. |backoff| mode is used by the use monitor to
+  // reschedule itself. If there's a monitor scheduled already and
+  // |backoff| is false, unschedules it first. Doesn't schedule a
+  // monitor for more than kUseMonitorIntervalMax seconds in the
+  // future (see metrics_daemon.cc). Returns true if a new use monitor
+  // was scheduled, false otherwise (note that if |backoff| is false a
+  // new use monitor will always be scheduled).
+  bool ScheduleUseMonitor(int interval, bool backoff);
+
+  // Unschedules a scheduled use monitor, if any.
+  void UnscheduleUseMonitor();
+
   // Sends a stat to Chrome for transport to UMA (or prints it for
   // testing). See MetricsLibrary::SendToChrome in metrics_library.h
   // for a description of the arguments.
   void PublishMetric(const char* name, int sample,
                      int min, int max, int nbuckets);
 
-  // D-Bus message match strings.
-  static const char* dbus_matches_[];
+  // Testing mode.
+  bool testing_;
 
-  // Array of network states.
-  static const char* network_states_[kNumberNetworkStates];
+  // Current network state.
+  NetworkState network_state_;
 
-  // Array of power states.
-  static const char* power_states_[kNumberPowerStates];
+  // Timestamps last network state update.
+  time_t network_state_last_;
+
+  // Current power state.
+  PowerState power_state_;
+
+  // Current screen-saver state.
+  ScreenSaverState screensaver_state_;
+
+  // Current user session state.
+  SessionState session_state_;
+
+  // Is the user currently active: power is on, user session has
+  // started, screen is not locked.
+  bool user_active_;
+
+  // Timestamps last user active update.
+  time_t user_active_last_;
+
+  // Last stored daily use day (since epoch).
+  int daily_use_day_last_;
+
+  // Sleep period until the next daily usage aggregation performed by
+  // the daily use monitor (see ScheduleUseMonitor).
+  int usemon_interval_;
 
-  bool testing_;                  // just testing
-  NetworkState network_state_;    // current network state
-  time_t network_state_changed_;  // timestamp last net state change
-  PowerState power_state_;        // current power state
+  // Scheduled daily use monitor source (see ScheduleUseMonitor).
+  GSource* usemon_source_;
 };
 
 #endif  // METRICS_DAEMON_H_