Reland [telemetry] Timeline model cleanups

tools/telemetry/telemetry/core/timeline/counter.py

Index: tools/telemetry/telemetry/core/timeline/counter.py
diff --git a/tools/telemetry/telemetry/core/timeline/tracing/counter.py b/tools/telemetry/telemetry/core/timeline/counter.py
similarity index 50%
rename from tools/telemetry/telemetry/core/timeline/tracing/counter.py
rename to tools/telemetry/telemetry/core/timeline/counter.py
index 33f5e86b1b99414a3bc162ddc83ed8ca1b9e077f..f21f5162fe487a3979ba96c3816ca9919993c1b4 100644
--- a/tools/telemetry/telemetry/core/timeline/tracing/counter.py
+++ b/tools/telemetry/telemetry/core/timeline/counter.py
@@ -2,32 +2,56 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
-class Counter(object):
-  ''' Stores all the samples for a given counter.
-  '''
+import telemetry.core.timeline.event_container as event_container
+
+# Doesn't inherit from TimelineEvent because its only a temporary wrapper of a
+# counter sample into an event. During stable operation, the samples are stored
+# a dense array of values rather than in the long-form done by an Event.
+class CounterSample(object):
+  def __init__(self, counter, sample_index):
+    self._counter = counter
+    self._sample_index = sample_index
+
+  @property
+  def name(self):
+    return None
+
+  @property
+  def start(self):
+    return self._counter.timestamps[self._sample_index]
+
+  @start.setter
+  def start(self, start):
+    self._counter.timestamps[self._sample_index] = start
+
+  @property
+  def duration(self):
+    return 0
+
+  @property
+  def end(self):
+    return self.start
+
+
+class Counter(event_container.TimelineEventContainer):
+  """ Stores all the samples for a given counter.
+  """
   def __init__(self, parent, category, name):
-    self.parent = parent
-    self.full_name  = category + '.' + name
+    super(Counter, self).__init__(name, parent)
     self.category = category
-    self.name = name
+    self.full_name  = category + '.' + name
     self.samples = []
     self.timestamps = []
     self.series_names = []
     self.totals = []
     self.max_total = 0
-    self._bounds = None
 
-  @property
-  def min_timestamp(self):
-    if not self._bounds:
-      self.UpdateBounds()
-    return self._bounds[0]
+  def IterChildContainers(self):
+    return iter([])
 
-  @property
-  def max_timestamp(self):
-    if not self._bounds:
-      self.UpdateBounds()
-    return self._bounds[1]
+  def IterEventsInThisContainer(self):
+    for i in range(len(self.timestamps)):
+      yield CounterSample(self, i)
 
   @property
   def num_series(self):
@@ -37,7 +61,7 @@ class Counter(object):
   def num_samples(self):
     return len(self.timestamps)
 
-  def UpdateBounds(self):
+  def FinalizeImport(self):
     if self.num_series * self.num_samples != len(self.samples):
       raise ValueError(
           'Length of samples must be a multiple of length of timestamps.')
@@ -47,8 +71,6 @@ class Counter(object):
     if not len(self.samples):
       return
 
-    self._bounds = (self.timestamps[0], self.timestamps[-1])
-
     max_total = None
     for i in xrange(self.num_samples):
       total = 0
@@ -58,4 +80,3 @@ class Counter(object):
       if max_total is None or total > max_total:
         max_total = total
     self.max_total = max_total
-