add GetBattorPathFromPhoneSerial to find_usb_devices

devil/devil/utils/battor_device_mapping.py

Index: devil/devil/utils/battor_device_mapping.py
diff --git a/devil/devil/utils/battor_device_mapping.py b/devil/devil/utils/battor_device_mapping.py
new file mode 100644
index 0000000000000000000000000000000000000000..1abb504298508c48baae286441e1323f98bd8ce2
--- /dev/null
+++ b/devil/devil/utils/battor_device_mapping.py
@@ -0,0 +1,207 @@
+#!/usr/bin/python
+# Copyright 2016 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
+import collections
+
+from devil import base_error
+from devil.utils import usb_hubs
+from devil.utils import find_usb_devices
+
+def GetBattorList(device_tree_map):
+  return [x for x in find_usb_devices.GetTTYList()
+          if IsBattor(x, device_tree_map)]
+
+
+def IsBattor(tty_string, device_tree_map):
+  (bus, device) = find_usb_devices.GetBusDeviceFromTTY(tty_string)
+  node = device_tree_map[bus].FindDeviceNumber(device)
+  return '0403:6001' in node.desc

[jbudorick, 2016/03/31 20:57:31]

This holds for all BattOrs? This logic changed from earlier this week...

[alexandermont, 2016/03/31 22:11:18]

Yes. I did test this with several different BattOrs. The "ID" here is a vendor
ID (the 4 hexdigits before the : ) and a prodoct ID (the 4 hexdigits after the :
). The reason I changed it to look at the ID rather than the rest of the string
is that I found out that the ID number is stable but the rest of the string is
not necessarily stable.

+

[jbudorick, 2016/03/31 20:57:31]

nit: two blank lines between functions at module scope

[alexandermont, 2016/03/31 22:11:18]

Done

+def GetBattorSerialNumbers(device_tree_map):
+  for x in find_usb_devices.GetTTYList():
+    if IsBattor(x, device_tree_map):
+      (bus, device) = find_usb_devices.GetBusDeviceFromTTY(x)
+      devnode = device_tree_map[bus].FindDeviceNumber(device)
+      yield devnode.serial
+
+class BattorError(base_error.BaseError):
+  pass
+
+def ReadSerialMapFile(filename):
+  """Reads JSON file giving phone-to-battor serial number map.
+
+  Parses a JSON file consisting of a list of items of the following form:
+  [{'phone': <phone serial 1>, 'battor': <battor serial 1>},
+  {'phone': <phone serial 2>, 'battor': <battor serial 2>}, ...]
+
+  indicating which phone serial numbers should be matched with
+  which BattOr serial numbers. Returns dictionary of the form:
+
+  {<phone serial 1>: <BattOr serial 1>,
+   <phone serial 2>: <BattOr serial 2>}
+
+  Args:
+      filename: Name of file to read.
+  """
+  result = {}
+  with open(filename, 'r') as infile:
+    in_dict = json.load(infile)
+  for x in in_dict:
+    result[x['phone']] = x['battor']
+  return result
+
+def GenerateSerialMapFile(filename, hub_types=None):
+  """Writes a map of phone serial numbers to BattOr serial numbers to file.
+
+  Writes a JSON file consisting of a list of items of the following form:
+  [{'phone': <phone serial 1>, 'battor': <battor serial 1>},
+  {'phone': <phone serial 2>, 'battor': <battor serial 2>}, ...]
+
+  indicating which phone serial numbers should be matched with
+  which BattOr serial numbers. Mapping is based on the physical port numbers
+  of the hubs that the BattOrs and phones are connected to.
+
+  Args:
+      filename: Name of file to write.
+  """
+  result = []
+  for (phone, battor) in GenerateSerialMap(hub_types).iteritems():
+    result.append({'phone': phone, 'battor': battor})
+  with open(filename, 'w') as outfile:
+    json.dump(result, outfile)
+
+def GenerateSerialMap(hub_types=None):
+  """Generates a map of phone serial numbers to BattOr serial numbers.
+
+  Generates a dict of:
+  {<phone serial 1>: <battor serial 1>,
+   <phone serial 2>: <battor serial 2>}
+  indicating which phone serial numbers should be matched with
+  which BattOr serial numbers. Mapping is based on the physical port numbers
+  of the hubs that the BattOrs and phones are connected to.
+
+  Args:
+      hub_types: List of hub types to check for.
+      Defaults to ['plugable_7port']
+  """
+  hub_types = [usb_hubs.GetHubType(x)
+               for x in hub_types or ['plugable_7port']]
+  devtree = find_usb_devices.GetBusNumberToDeviceTreeMap()
+
+  # List of serial numbers in the system that represent BattOrs.
+  battor_serials = list(GetBattorSerialNumbers(devtree))
+
+  # List of dictionaries, one for each hub, that maps the physical
+  # port number to the serial number of that hub. For instance, in a 2
+  # hub system, this could return [{1:'ab', 2:'cd'}, {1:'jkl', 2:'xyz'}]
+  # where 'ab' and 'cd' are the phone serial numbers and 'jkl' and 'xyz'
+  # are the BattOr serial numbers.
+  port_to_serial = find_usb_devices.GetAllPhysicalPortToSerialMaps(
+      hub_types, device_tree_map=devtree)
+
+  class serials(object):
+    def __init__(self):
+      self.phone = None
+      self.battor = None
+
+  # Map of {physical port number: [phone serial #, BattOr serial #]. This
+  # map is populated by executing the code below. For instance, in the above
+  # example, after the code below is executed, port_to_devices would equal
+  # {1: ['ab', 'jkl'], 2: ['cd', 'xyz']}
+  port_to_devices = collections.defaultdict(serials)
+  for hub in port_to_serial:
+    for (port, serial) in hub.iteritems():
+      if serial in battor_serials:
+        if port_to_devices[port].battor is not None:
+          raise BattorError('Multiple BattOrs on same port number')
+        else:
+          port_to_devices[port].battor = serial
+      else:
+        if port_to_devices[port].phone is not None:
+          raise BattorError('Multiple phones on same port number')
+        else:
+          port_to_devices[port].phone = serial
+
+  # Turn the port_to_devices map into a map of the form
+  # {phone serial number: BattOr serial number}.
+  result = {}
+  for pair in port_to_devices.values():
+    result[pair.phone] = pair.battor

[jbudorick, 2016/03/31 20:57:31]

Wasn't this going to do some error checking for None values of either pair.phone
or pair.battor?

[alexandermont, 2016/03/31 22:11:18]

Done.

+  return result
+
+def _PhoneToPathMap(serial, serial_map, devtree):

[jbudorick, 2016/03/31 20:57:31]

Are callers ok with this returning None if it doesn't find a node matching the
battor serial?

[alexandermont, 2016/03/31 22:11:18]

Yes. The only caller is GetBattorPathFromPhoneSerial, which checks the output of
this function and raises a BattorError if it is None.

+  """Maps phone serial number to TTY path, assuming serial map is provided."""
+  battor_serial = serial_map[serial]
+  for tree in devtree.values():
+    for node in tree.AllNodes():
+      if isinstance(node, find_usb_devices.USBDeviceNode):
+        if node.serial == battor_serial:
+          bus_device_to_tty = find_usb_devices.GetBusDeviceToTTYMap()
+          bus_device = (node.bus_num, node.device_num)
+          try:
+            return bus_device_to_tty[bus_device]
+          except KeyError:
+            raise BattorError('Device with given serial number not a BattOr '
+                              '(does not have TTY path)')
+
+
+def GetBattorPathFromPhoneSerial(serial, serial_map=None,
+                                 serial_map_file=None):
+  """Gets the TTY path (e.g. '/dev/ttyUSB0')  to communicate with the BattOr.
+
+  (1) If serial_map is given, it is treated as a dictionary mapping
+  phone serial numbers to BattOr serial numbers. This function will get the
+  TTY path for the given BattOr serial number.
+
+  (2) If serial_map_file is given, it is treated as the name of a
+  phone-to-BattOr mapping file (generated with GenerateSerialMapFile)
+  and this will be loaded and used as the dict to map port numbers to
+  BattOr serial numbers.
+
+  You can only give one of serial_map and serial_map_file.
+
+  Args:
+    serial: Serial number of phone connected on the same physical port that
+    the BattOr is connected to.
+    serial_map: Map of phone serial numbers to BattOr serial numbers, given
+    as a dictionary.
+    serial_map_file: Map of phone serial numbers to BattOr serial numbers,
+    given as a file.
+    hub_types: List of hub types to check for. Used only if serial_map_file
+    is None.
+
+  Returns:
+    Device string used to communicate with device.
+
+  Raises:
+    ValueError: If serial number is not given.
+    BattorError: If BattOr not found or unexpected USB topology.
+  """
+  # If there's only one BattOr connected to the system, just use that one.
+  # This allows for use on, e.g., a developer's workstation with no hubs.
+  devtree = find_usb_devices.GetBusNumberToDeviceTreeMap()
+  all_battors = GetBattorList(devtree)
+  if len(all_battors) == 1:
+    return '/dev/' + all_battors[0]
+
+  if serial_map and serial_map_file:
+    raise ValueError('Cannot specify both serial_map and serial_map_file')
+
+  if serial_map_file:
+    serial_map = ReadSerialMapFile(serial_map)
+
+  if not serial:

[jbudorick, 2016/03/31 20:57:31]

nit: move this check before the serial_map and serial_map_file handling.

[alexandermont, 2016/03/31 22:11:18]

Done

+    raise BattorError('Two or more BattOrs connected, no serial provided')
+
+  tty_string = _PhoneToPathMap(serial, serial_map, devtree)
+
+  if not tty_string:
+    raise BattorError('No device with given serial number detected.')
+
+  if IsBattor(tty_string, devtree):
+    return '/dev/' + tty_string
+  else:
+    raise BattorError('Device with given serial number is not a BattOr.')