Add policies to control power management on the Chrome OS login screen

chromeos/dbus/power_policy_controller.cc

 // Copyright (c) 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 "chromeos/dbus/power_policy_controller.h"
 
 #include "base/format_macros.h"
 #include "base/logging.h"
 #include "base/strings/string_util.h"
 #include "base/strings/stringprintf.h"
@@ skipping 139 matching lines @@
   delays->set_screen_off_ms(values.ac_screen_off_delay_ms);
   delays->set_screen_lock_ms(values.ac_screen_lock_delay_ms);
   delays->set_idle_warning_ms(values.ac_idle_warning_delay_ms);
   delays->set_idle_ms(values.ac_idle_delay_ms);
 
   // If screen-locking is enabled, ensure that the screen is locked soon
   // after it's turned off due to user inactivity.
   int64 lock_ms = delays->screen_off_ms() + kScreenLockAfterOffDelayMs;
   if (values.enable_screen_lock && delays->screen_off_ms() > 0 &&
       (delays->screen_lock_ms() <= 0 || lock_ms < delays->screen_lock_ms()) &&
-      lock_ms < delays->idle_ms())
+      lock_ms < delays->idle_ms()) {

[Daniel Erat, 2013/06/28 17:05:09]

for what it's worth, i've been told in previous reviews that curly brackets
should be left off in this case. i don't care much one way or the other

[bartfab (slow), 2013/07/01 12:32:59]

The style guide definitely does not forbid them:

"In general, curly braces are not required for single-line statements, but they
are allowed if you like them; conditional or loop statements with complex
conditions or statements may be more readable with curly braces. Some projects
require that an if must always always have an accompanying brace."

And I have been told in previous reviews that curly braces would be required
here as it is seen as a multi-line statement. Given the choice, I would prefer
to keep them.

[Daniel Erat, 2013/07/01 14:29:05]

sounds fine. for what it's worth, the distinction that i've heard is that a
multi-line statement requires braces, while a multi-line condition with a
single-line statement shouldn't have them:

if (SomeVeryLongConditionIsTrue() &&
    SomeOtherVeryLongConditionIsTrue())
  DoSomething();

if (ConditionIsTrue) {
  DoSomethingWithALotOfArguments(
      this_variable_name_seems_awfully_long,
      really_cant_you_come_up_with_something_shorter,
      it_is_not_like_we_are_paid_by_the_line_after_all);
}

but i don't think that this has ever been spelled out in a style guide, and i'm
not interested in wading through years of style discussions on chromium-dev to
see if it's ever actually come up there. :-P

[bartfab (slow), 2013/07/01 14:53:08]

It seems that different reviewers interpret the style guide differently. If you
are OK with the code as it is, I will just leave it like that rather than
starting a bikeshed discussion on chromium-dev :).

[Daniel Erat, 2013/07/01 14:53:52]

i'm certainly fine with leaving it like this

     delays->set_screen_lock_ms(lock_ms);
+  }
 
   delays = prefs_policy_.mutable_battery_delays();
   delays->set_screen_dim_ms(values.battery_screen_dim_delay_ms);
   delays->set_screen_off_ms(values.battery_screen_off_delay_ms);
   delays->set_screen_lock_ms(values.battery_screen_lock_delay_ms);
   delays->set_idle_warning_ms(values.battery_idle_warning_delay_ms);
   delays->set_idle_ms(values.battery_idle_delay_ms);
 
   lock_ms = delays->screen_off_ms() + kScreenLockAfterOffDelayMs;
   if (values.enable_screen_lock && delays->screen_off_ms() > 0 &&
       (delays->screen_lock_ms() <= 0 || lock_ms < delays->screen_lock_ms()) &&
-      lock_ms < delays->idle_ms())
+      lock_ms < delays->idle_ms()) {
     delays->set_screen_lock_ms(lock_ms);
+  }
 
   prefs_policy_.set_ac_idle_action(GetProtoAction(values.ac_idle_action));
   prefs_policy_.set_battery_idle_action(
       GetProtoAction(values.battery_idle_action));
   prefs_policy_.set_lid_closed_action(GetProtoAction(values.lid_closed_action));
   prefs_policy_.set_use_audio_activity(values.use_audio_activity);
   prefs_policy_.set_use_video_activity(values.use_video_activity);
   prefs_policy_.set_presentation_screen_dim_delay_factor(
       values.presentation_screen_dim_delay_factor);
   prefs_policy_.set_user_activity_screen_dim_delay_factor(
       values.user_activity_screen_dim_delay_factor);
 
   honor_screen_wake_locks_ = values.allow_screen_wake_locks;
 
   prefs_were_set_ = true;
   SendCurrentPolicy();
 }
 
+void PowerPolicyController::ClearPrefs() {
+  prefs_policy_.Clear();
+  honor_screen_wake_locks_ = true;
+  prefs_were_set_ = false;
+  SendCurrentPolicy();
+}
+
 int PowerPolicyController::AddScreenWakeLock(const std::string& reason) {
   int id = next_wake_lock_id_++;
   screen_wake_locks_[id] = reason;
   SendCurrentPolicy();
   return id;
 }
 
 int PowerPolicyController::AddSystemWakeLock(const std::string& reason) {
   int id = next_wake_lock_id_++;
   system_wake_locks_[id] = reason;
@@ skipping 59 matching lines @@
   if (!reason.empty())
     policy.set_reason(reason);
   client_->SetPolicy(policy);
 }
 
 void PowerPolicyController::SendEmptyPolicy() {
   client_->SetPolicy(power_manager::PowerManagementPolicy());
 }
 
 }  // namespace chromeos