add GetBattorPathFromPhoneSerial to find_usb_devices

devil/devil/utils/usb_hubs.py

Index: devil/devil/utils/usb_hubs.py
diff --git a/devil/devil/utils/usb_hubs.py b/devil/devil/utils/usb_hubs.py
new file mode 100644
index 0000000000000000000000000000000000000000..a37cb3b47b56ea004f80e4e296634b4cab86fad6
--- /dev/null
+++ b/devil/devil/utils/usb_hubs.py
@@ -0,0 +1,98 @@
+# 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.
+
+PLUGABLE_7PORT_LAYOUT = {1:7,
+                         2:6,
+                         3:5,
+                         4:{1:4, 2:3, 3:2, 4:1}}
+
+class HubType(object):
+  def __init__(self, id_func, port_mapping):
+    """Defines a type of hub.
+
+    Args:
+      id_func: [USBNode -> bool] is a function that can be run on a node
+        to determine if the node represents this type of hub.
+      port_mapping: [dict(int:(int|dict))] maps virtual to physical port
+        numbers. For instance, {3:1, 1:2, 2:3} means that virtual port 3
+        corresponds to physical port 1, virtual port 1 corresponds to physical
+        port 2, and virtual port 2 corresponds to physical port 3. In the
+        case of hubs with "internal" topology, this is represented by nested
+        maps. For instance, {1:{1:1,2:2},2:{1:3,2:4}} means, e.g. that the
+        device plugged into physical port 3 will show up as being connected
+        to port 1, on a device which is connected to port 2 on the hub.
+    """
+    self._id_func = id_func
+    # v2p = "virtual to physical" ports
+    self._v2p_port = port_mapping
+
+  def IsType(self, node):
+    """Determines if the given Node is a hub of this type.
+
+    Args:
+      node: [USBNode] Node to check.
+    """
+    return self._id_func(node)
+
+  def GetPhysicalPortToNodeTuples(self, node):
+    """Gets devices connected to the physical ports on a hub of this type.
+
+    Args:
+      node: [USBNode] Node representing a hub of this type.
+
+    Yields:
+      A series of (int, USBNode) tuples giving a physical port
+      and the USBNode connected to it.
+
+    Raises:
+      ValueError: If the given node isn't a hub of this type.
+    """
+    if self.IsType(node):
+      for res in self._GppHelper(node, self._v2p_port):
+        yield res
+    else:
+      raise ValueError('Node must be a hub of this type')
+
+  def _GppHelper(self, node, mapping):
+    """Helper function for GetPhysicalPortToNodeMap.
+
+    Gets devices connected to physical ports, based on device tree
+    rooted at the given node and the mapping between virtual and physical
+    ports.
+
+    Args:
+      node: [USBNode] Root of tree to search for devices.
+      mapping: [dict] Mapping between virtual and physical ports.
+
+    Yields:
+      A series of (int, USBNode) tuples giving a physical port
+      and the Node connected to it.
+    """
+    for (virtual, physical) in mapping.iteritems():
+      if node.HasPort(virtual):
+        if isinstance(physical, dict):
+          for res in self._GppHelper(node.PortToDevice(virtual), physical):
+            yield res
+        else:
+          yield (physical, node.PortToDevice(virtual))
+
+def _is_plugable_7port_hub(node):
+  """Check if a node is a Plugable 7-Port Hub
+  (Model USB2-HUB7BC)
+  The topology of this device is a 4-port hub,
+  with another 4-port hub connected on port 4.
+  """
+  if '1a40:0101' not in node.desc:
+    return False
+  if not node.HasPort(4):
+    return False
+  return '1a40:0101' in node.PortToDevice(4).desc
+
+PLUGABLE_7PORT = HubType(_is_plugable_7port_hub, PLUGABLE_7PORT_LAYOUT)
+
+def GetHubType(type_name):
+  if type_name == 'plugable_7port':
+    return PLUGABLE_7PORT
+  else:
+    raise ValueError('Invalid hub type')