commit ff73cf261ccf5daef1489db05d11b49aeab270a0
author Alex Vakulenko <avakulenko@chromium.org> Wed Oct 29 09:53:52 2014 -0700
committer chrome-internal-fetch <chrome-internal-fetch@google.com> Wed Nov 05 18:30:14 2014 +0000
tree c2abddefa60e4df713a63f3cca202bea0eae94b1
parent 6d2569e4260293816b8b9416d5e6993f843869b2

buffet: Fix issues in StateChangeQueue

Addressed additional code review issues brought after the original
code has been published.

- NotifyPropertiesUpdated() now takes timestamp and property set
  as separate parameters to simplify implementation of StateManager.
- StateChangeQueue::max_queue_size_ is made 'const'
- StateChangeQueue now maintains a time-to-event map instead of
  a vector of StateChange. This allows to keep the events sorted
  by time stamp. Also adding discrete events with the same time stamp
  coalesces the property changes.
- added a unit test for coalescing property set changes based on
  the timestamp.

BUG=None
TEST=FEATURES=test emerge-link buffet

Change-Id: I309816d1f040558620fa68a844b05251d0e4319b
Reviewed-on: https://chromium-review.googlesource.com/226300
Reviewed-by: Christopher Wiley <wiley@chromium.org>
Reviewed-by: Anton Muhin <antonm@chromium.org>
Commit-Queue: Alex Vakulenko <avakulenko@chromium.org>
Tested-by: Alex Vakulenko <avakulenko@chromium.org>

buffet/states/state_change_queue_interface.h

diff --git a/buffet/states/state_change_queue_interface.h b/buffet/states/state_change_queue_interface.h
index 5810bff..84704dd 100644
--- a/buffet/states/state_change_queue_interface.h
+++ b/buffet/states/state_change_queue_interface.h
@@ -14,12 +14,14 @@
 
 // A simple notification record event to track device state changes.
 // The |timestamp| records the time of the state change.
-// |property_set| contains a property set with the new property values.
-// The property set contains only the properties updated at the time the event
-// was recorded.
+// |changed_properties| contains a property set with the new property values
+// which were updated at the time the event was recorded.
 struct StateChange {
+  StateChange(base::Time time,
+              chromeos::VariantDictionary properties)
+    : timestamp(time), changed_properties(std::move(properties)) {}
   base::Time timestamp;
-  chromeos::VariantDictionary property_set;
+  chromeos::VariantDictionary changed_properties;
 };
 
 // An abstract interface to StateChangeQueue to record and retrieve state
@@ -30,7 +32,9 @@
   virtual bool IsEmpty() const = 0;
 
   // Called by StateManager when device state properties are updated.
-  virtual bool NotifyPropertiesUpdated(const StateChange& change) = 0;
+  virtual bool NotifyPropertiesUpdated(
+      base::Time timestamp,
+      chromeos::VariantDictionary changed_properties) = 0;
 
   // Returns the recorded state changes since last time this method was called.
   virtual std::vector<StateChange> GetAndClearRecordedStateChanges() = 0;