Cleanup of page_measurement_results object

tools/telemetry/telemetry/value/histogram.py

Index: tools/telemetry/telemetry/value/histogram.py
diff --git a/tools/telemetry/telemetry/value/histogram.py b/tools/telemetry/telemetry/value/histogram.py
new file mode 100644
index 0000000000000000000000000000000000000000..a681cf26b6d112fb6c44655d3a1fd76d6f424682
--- /dev/null
+++ b/tools/telemetry/telemetry/value/histogram.py
@@ -0,0 +1,97 @@
+# 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.
+import json
+
+from telemetry import value as value_module
+from telemetry.page import perf_tests_helper
+
+class HistogramValueBucket(object):
+  def __init__(self, low, high, count=0):
+    self.low = low
+    self.high = high
+    self.count = count
+
+  def ToJSONString(self):
+    return '{%s}' % ', '.join([
+      '"low": %i' % self.low,
+      '"high": %i' % self.high,
+      '"count": %i' % self.count])
+
+class HistogramValue(value_module.Value):
+  def __init__(self, page, name, units,
+               raw_value=None, raw_value_json=None, important=True):
+    super(HistogramValue, self).__init__(page, name, units, important)
+    if raw_value_json:
+      assert raw_value == None, 'Dont specify both raw_value and raw_value_json'
+      raw_value = json.loads(raw_value_json)
+    if raw_value:
+      assert 'buckets' in raw_value
+      assert isinstance(raw_value['buckets'], list)
+      self.buckets = []
+      for bucket in raw_value['buckets']:
+        self.buckets.append(HistogramValueBucket(
+          low=bucket['low'],
+          high=bucket['high'],
+          count=bucket['count']))
+    else:
+      self.buckets = []
+
+  def __repr__(self):
+    if self.page:
+      page_name = self.page.url
+    else:
+      page_name = None
+    return 'HistogramValue(%s, %s, %s, raw_json_string="%s", important=%s)' % (
+      page_name,
+      self.name, self.units,
+      self.ToJSONString(),
+      self.important)
+
+  def GetBuildbotDataType(self, output_context):
+    if self._IsImportantGivenOutputIntent(output_context):
+      return 'histogram'
+    return 'unimportant-histogram'
+
+  def GetBuildbotValue(self):
+    # More buildbot insanity: perf_tests_results_helper requires the histogram
+    # to be an array of size one.
+    return [self.ToJSONString()]
+
+  def ToJSONString(self):
+    # This has to hand-JSONify the histogram to ensure the order of keys
+    # produced is stable across different systems.
+    #
+    # This is done because the buildbot unittests are string equality
+    # assertions. Thus, tests that contain histograms require stable
+    # stringification of the histogram.
+    #
+    # Sigh, buildbot, Y U gotta be that way.
+    return '{"buckets": [%s]}' % (
+      ', '.join([b.ToJSONString() for b in self.buckets]))
+
+  def GetRepresentativeNumber(self):
+    (mean, _) = perf_tests_helper.GeomMeanAndStdDevFromHistogram(
+        self.ToJSONString())
+    return mean
+
+  def GetRepresentativeString(self):
+    return self.GetBuildbotValue()
+
+  @classmethod
+  def MergeLikeValuesFromSamePage(cls, values):
+    assert len(values) > 0
+    v0 = values[0]
+    return HistogramValue(
+        v0.page, v0.name, v0.units,
+        raw_value_json=v0.ToJSONString(),
+        important=v0.important)
+
+  @classmethod
+  def MergeLikeValuesFromDifferentPages(cls, values,
+                                        group_by_name_suffix=False):
+    # Histograms cannot be merged across pages, at least for now. It should be
+    # theoretically possible, just requires more work. Instead, return None.
+    # This signals to the merging code that the data is unmergable and it will
+    # cope accordingly.
+    return None