Update parsing of dumpsys batterystats

tools/telemetry/telemetry/core/platform/power_monitor/android_dumpsys_power_monitor.py

Index: tools/telemetry/telemetry/core/platform/power_monitor/android_dumpsys_power_monitor.py
diff --git a/tools/telemetry/telemetry/core/platform/power_monitor/android_dumpsys_power_monitor.py b/tools/telemetry/telemetry/core/platform/power_monitor/android_dumpsys_power_monitor.py
index 9432d7079a9e96acfe9b4b0ed88084df2b2e4fa8..e1e58198e26d860d452dfe5d3de3ccef4bcb29ce 100644
--- a/tools/telemetry/telemetry/core/platform/power_monitor/android_dumpsys_power_monitor.py
+++ b/tools/telemetry/telemetry/core/platform/power_monitor/android_dumpsys_power_monitor.py
@@ -57,6 +57,9 @@ class DumpsysPowerMonitor(power_monitor.PowerMonitor):
   def ParseSamplingOutput(package, dumpsys_output):
     """Parse output of 'dumpsys batterystats -c'
 
+    See:
+    https://android.googlesource.com/platform/frameworks/base/+/master/core/java/android/os/BatteryStats.java
+
     Returns:
         Dictionary in the format returned by StopMonitoringPower().
     """
@@ -65,32 +68,53 @@ class DumpsysPowerMonitor(power_monitor.PowerMonitor):
     out_dict['identifier'] = 'dumpsys'
     out_dict['power_samples_mw'] = []
 
-    # csv columns
+    # The list of useful CSV columns.
+    # Index of the column containing the format version.
     DUMP_VERSION_INDEX = 0
-    COLUMN_TYPE_INDEX = 3
+    # Index of the column containing the type of the row.
+    ROW_TYPE_INDEX = 3
+
+    # Index for columns of type unique identifier ('uid')
+    # Index of the column containing the uid.
     PACKAGE_UID_INDEX = 4
-    PWI_POWER_COMSUMPTION_INDEX = 5
+    # Index of the column containing the application package.
+    PACKAGE_NAME_INDEX = 5
+
+    # Index for columns of type power use ('pwi')
+    # The column containing the uid of the item.
     PWI_UID_INDEX = 1
+    # The column containing the type of consumption. Only consumtion since last
+    # charge are of interest here.
     PWI_AGGREGATION_INDEX = 2
-    PWI_SUBTYPE_INDEX = 4
+    # The column containing the amount of power used, in mah.
+    PWI_POWER_COMSUMPTION_INDEX = 5
     csvreader = csv.reader(dumpsys_output)
-    entries_by_type = defaultdict(list)
+    uid_entries = {}
+    pwi_entries = defaultdict(list)
     for entry in csvreader:
-      if len(entry) < 4 or entry[DUMP_VERSION_INDEX] != '7':
+      if entry[DUMP_VERSION_INDEX] != '8':
+        # Wrong file version.
+        break

[tonyg, 2014/07/22 03:12:50]

Should we logging.warn here?

[qsr, 2014/07/22 07:51:23]

 We will warn line 112 if we reach this.

+      if ROW_TYPE_INDEX >= len(entry):
         continue
-      entries_by_type[entry[COLUMN_TYPE_INDEX]].append(entry)
+      if entry[ROW_TYPE_INDEX] == 'uid':
+        current_package = entry[PACKAGE_NAME_INDEX]
+        assert current_package not in uid_entries
+        uid_entries[current_package] = entry[PACKAGE_UID_INDEX]
+      elif (PWI_POWER_COMSUMPTION_INDEX < len(entry) and
+            entry[ROW_TYPE_INDEX] == 'pwi' and
+            entry[PWI_AGGREGATION_INDEX] == 'l'):
+        pwi_entries[entry[PWI_UID_INDEX]].append(
+            float(entry[PWI_POWER_COMSUMPTION_INDEX]))
+
     # Find the uid of for the given package.
-    if not package in entries_by_type:
-      logging.warning('Unable to parse dumpsys output. Please upgrade the OS.')
+    if not package in uid_entries:
+      logging.warning('Unable to parse dumpsys output. ' +
+                      'Please upgrade the OS version of the device.')
       out_dict['energy_consumption_mwh'] = 0
       return out_dict
-    assert len(entries_by_type[package]) == 1, 'Multiple entries for package.'
-    uid = entries_by_type[package][0][PACKAGE_UID_INDEX]
-    consumptions_mah = [float(entry[PWI_POWER_COMSUMPTION_INDEX])
-                        for entry in entries_by_type['pwi']
-                        if entry[PWI_UID_INDEX] == uid and
-                        entry[PWI_AGGREGATION_INDEX] == 't' and
-                        entry[PWI_SUBTYPE_INDEX] == 'uid']
+    uid = uid_entries[package]
+    consumptions_mah = pwi_entries[uid]
     consumption_mah = sum(consumptions_mah)
     # Converting at a nominal voltage of 4.0V, as those values are obtained by a
     # heuristic, and 4.0V is the voltage we set when using a monsoon device.