Add device status reports to policy requests.

chrome/browser/policy/device_status_collector.cc

+// Copyright (c) 2011 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 "chrome/browser/policy/device_status_collector.h"
+
+#include "base/bind.h"
+#include "base/callback.h"
+#include "base/message_loop.h"
+#include "base/string_number_conversions.h"
+#include "base/task.h"
+#include "base/time.h"
+#include "chrome/browser/idle.h"
+#include "chrome/browser/policy/proto/device_management_backend.pb.h"
+#include "chrome/browser/prefs/pref_service.h"
+#include "chrome/browser/prefs/scoped_user_pref_update.h"
+
+using base::Time;
+using base::TimeDelta;
+
+namespace em = enterprise_management;
+
+namespace {
+// How many seconds of inactivity triggers the idle state.
+const unsigned int kIdleStateThresholdSeconds = 300;
+
+// The maximum number of time periods stored in the local state.
+const unsigned int kMaxStoredActivePeriods = 500;
+
+// Stores the baseline timestamp, to which the active periods are relative.
+const char* const kPrefBaselineTime = "device_status.baseline_timestamp";
+
+// Stores a list of timestamps representing device active periods.
+const char* const kPrefDeviceActivePeriods = "device_status.active_periods";
+
+bool GetTimestamp(const ListValue* list, int index, int64* out_value) {
+  std::string string_value;
+  if (list->GetString(index, &string_value))
+    return base::StringToInt64(string_value, out_value);
+  return false;
+}
+
+}  // namespace
+
+namespace policy {
+
+DeviceStatusCollector::DeviceStatusCollector(PrefService* local_state)
+    : max_stored_active_periods_(kMaxStoredActivePeriods),
+      local_state_(local_state),
+      last_idle_check_(Time()),
+      last_idle_state_(IDLE_STATE_UNKNOWN) {
+  // Only start the timer if we have a message loop. The only time this should
+  // matter is in unit_tests.
+  if (MessageLoop::current()) {

[Mattias Nissler (ping if slow), 2011/12/06 15:20:18]

That's a poor way of detecting whether this is a unit test :) Can't you just add
a message loop to the unit test? The task won't run, but as far as I understand,
that should be OK for the tests.

[Patrick Dubroy, 2011/12/06 16:41:57]

Done.

+    timer_.Start(FROM_HERE,
+                 TimeDelta::FromSeconds(
+                     DeviceStatusCollector::kPollIntervalSeconds),
+                 this, &DeviceStatusCollector::CheckIdleState);
+  }
+}
+
+// static
+void DeviceStatusCollector::RegisterPrefs(PrefService* local_state) {
+  local_state->RegisterInt64Pref(kPrefBaselineTime, Time::Now().ToTimeT());
+  local_state->RegisterListPref(kPrefDeviceActivePeriods, new ListValue);
+}
+
+void DeviceStatusCollector::CheckIdleState() {
+  CalculateIdleState(kIdleStateThresholdSeconds,
+      base::Bind(&DeviceStatusCollector::IdleStateCallback,
+                 base::Unretained(this)));
+}
+
+Time DeviceStatusCollector::GetCurrentTime() {
+  return Time::Now();
+}
+
+void DeviceStatusCollector::AddActivePeriod(Time start, Time end) {
+  // Maintain the list of active periods in a local_state pref.
+  ListPrefUpdate update(local_state_, kPrefDeviceActivePeriods);
+  ListValue* active_periods = update.Get();
+
+  // Cap the number of active periods that we store.
+  if (active_periods->GetSize() >= 2 * max_stored_active_periods_)
+    return;
+
+  Time epoch = Time::UnixEpoch();
+  int64 start_timestamp = (start - epoch).InMilliseconds();
+  Value* end_value = new StringValue(
+      base::Int64ToString((end - epoch).InMilliseconds()));
+
+  int list_size = active_periods->GetSize();
+  DCHECK(list_size % 2 == 0);
+
+  // Check if this period can be combined with the previous one.
+  if (list_size > 0 && last_idle_state_ == IDLE_STATE_ACTIVE) {
+    int64 last_period_end;
+    if (GetTimestamp(active_periods, list_size - 1, &last_period_end) &&
+        last_period_end == start_timestamp) {
+      active_periods->Set(list_size - 1, end_value);
+      return;
+    }
+  }
+  // Add a new period to the list.
+  active_periods->Append(
+      new StringValue(base::Int64ToString(start_timestamp)));
+  active_periods->Append(end_value);
+}
+
+void DeviceStatusCollector::IdleStateCallback(IdleState state) {
+  Time now = GetCurrentTime();
+
+  if (state == IDLE_STATE_ACTIVE) {
+    unsigned int poll_interval = DeviceStatusCollector::kPollIntervalSeconds;
+
+    // If it's been too long since the last report, assume that the system was
+    // in standby, and only count a single interval of activity.
+    if ((now - last_idle_check_).InSeconds() >= (2 * poll_interval))
+      AddActivePeriod(now - TimeDelta::FromSeconds(poll_interval), now);
+    else
+      AddActivePeriod(last_idle_check_, now);
+  }
+  last_idle_check_ = now;
+  last_idle_state_ = state;
+}
+
+void DeviceStatusCollector::GetStatus(em::DeviceStatusReportRequest* request) {
+  const ListValue* active_periods =
+      local_state_->GetList(kPrefDeviceActivePeriods);
+  em::TimePeriod* time_period;
+
+  DCHECK(active_periods->GetSize() % 2 == 0);
+
+  int period_count = active_periods->GetSize() / 2;
+  for (int i = 0; i < period_count; i++) {
+    int64 start, end;
+
+    if (!GetTimestamp(active_periods, 2 * i, &start) ||
+        !GetTimestamp(active_periods, 2 * i + 1, &end) ||
+        end < start) {
+      // Something is amiss -- bail out.
+      NOTREACHED();
+      break;
+    }
+    time_period = request->add_active_time();
+    time_period->set_start_timestamp(start);
+    time_period->set_end_timestamp(end);
+  }
+  ListPrefUpdate update(local_state_, kPrefDeviceActivePeriods);
+  update.Get()->Clear();
+}
+
+}  // namespace policy