Record policy usage statistics every 24 hours.

chrome/browser/policy/policy_statistics_collector.cc

+// Copyright (c) 2012 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/policy_statistics_collector.h"
+
+#include "base/bind.h"
+#include "base/location.h"
+#include "base/logging.h"

[Joao da Silva, 2012/09/12 13:29:38]

Used?

[qfel, 2012/09/18 11:30:56]

Oh, that DCHECK is no longer there.
Done.

+#include "base/metrics/histogram.h"
+#include "base/task_runner.h"
+#include "chrome/browser/policy/policy_service.h"
+#include "chrome/browser/prefs/pref_service.h"
+#include "chrome/common/pref_names.h"
+#include "policy/policy_constants.h"
+
+namespace policy {
+
+namespace {
+// The time delta specifying how often policy usage statistics are collected.
+const base::TimeDelta kStatisticsUpdateRate = base::TimeDelta::FromDays(1);

[Joao da Silva, 2012/09/12 13:29:38]

This requires a static initializer, which are avoided in chromium. Store the
default in an int instead.

[qfel, 2012/09/18 11:30:56]

Done.

+}
+
+PolicyStatisticsCollector::PolicyStatisticsCollector(
+    PolicyService* policy_service,
+    PrefService* prefs,
+    const scoped_refptr<base::TaskRunner>& task_runner)
+    : policy_service_(policy_service),
+      prefs_(prefs),
+      task_runner_(task_runner) {
+  base::Time last_update = base::Time::FromInternalValue(
+      prefs_->GetInt64(prefs::kLastPolicyStatisticsUpdate));
+  base::TimeDelta delay = base::Time::Now() - last_update;

[Joao da Silva, 2012/09/12 13:29:38]

|last_update| should be clamped to at most Now(). If for some reason it is much
larger than Now() then the next update will be in the far future (e.g. if the
system time is changed in a broken way).

[qfel, 2012/09/18 11:30:56]

Done.

+  if (delay >= kStatisticsUpdateRate)
+    CollectStatistics();
+  else
+    ScheduleUpdate(kStatisticsUpdateRate - delay);
+}
+
+PolicyStatisticsCollector::~PolicyStatisticsCollector() {
+}
+
+// static
+void PolicyStatisticsCollector::RegisterPrefs(PrefService* prefs) {
+  prefs->RegisterInt64Pref(prefs::kLastPolicyStatisticsUpdate, 0,
+                           PrefService::UNSYNCABLE_PREF);
+}
+
+void PolicyStatisticsCollector::CollectStatistics() {
+  const PolicyMap& policies = policy_service_->GetPolicies(POLICY_DOMAIN_CHROME,
+                                                           "");

[Mattias Nissler (ping if slow), 2012/09/12 13:06:27]

use std::string() instead of ""

[qfel, 2012/09/18 11:30:56]

Done.

+  const policy::PolicyDefinitionList* policy_list =
+      policy::GetChromePolicyDefinitionList();
+
+  // Set the boundary to be max policy id + 1. Note that this may decrease in
+  // future builds if the policy with maximum id is removed. This does not
+  // pose a problem.
+  int boundary = 0;
+  for (const policy::PolicyDefinitionList::Entry* policy = policy_list->begin;
+       policy != policy_list->end; ++policy) {
+    if (policy->id > boundary)

[Mattias Nissler (ping if slow), 2012/09/12 13:06:27]

boundary = std::max(policy->id, boundary)?

[qfel, 2012/09/18 11:30:56]

Why is it better?

+      boundary = policy->id;
+  }
+  boundary++;
+
+  // Collect statistics.
+  for (const policy::PolicyDefinitionList::Entry* policy = policy_list->begin;
+       policy != policy_list->end; ++policy) {
+    if (policies.Get(policy->name))
+      UMA_HISTOGRAM_ENUMERATION("Enterprise.Policies", policy->id, boundary);
+  }
+
+  // Take care of next update.
+  prefs_->SetInt64(prefs::kLastPolicyStatisticsUpdate,
+                   base::Time::Now().ToInternalValue());
+  ScheduleUpdate(kStatisticsUpdateRate);
+}
+
+void PolicyStatisticsCollector::ScheduleUpdate(base::TimeDelta delay) {
+  update_callback_.Reset(base::Bind(
+      &PolicyStatisticsCollector::CollectStatistics,
+      base::Unretained(this)));
+  task_runner_->PostDelayedTask(FROM_HERE, update_callback_.callback(), delay);
+}
+
+}  // namespace policy