rosaction.py

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# Author: Isaac Saito under the influence of rosmsg.__init__.py

# TODO 3/11/2013 (Isaac) This is moved from rqt_action pkg due to circular
# dependency issue. This rosaction is supposed to be moved (pull requested) to
# actionlib in the future.

"""
Modifying rosaction.__init__.py to add functionality for ROS Action.

Implements rosaction command-line tools.

The code API of the rosaction module is unstable (inheriting the status of
rosmsg)

(2/4/2013) Most of codes are not tested with actinlib. There's
"#NOT_TESTED_FROM_HERE" sign in the code below.
"""

from __future__ import print_function

import collections
import inspect
import os
import sys
import yaml
from optparse import OptionParser

import genmsg
# import genpy
import rosbag
import roslib
import roslib.message
import rospkg
import rospy

class ROSActionException(Exception): pass
class ROSActionProtoException(Exception): pass
class RosActionProtoArgsException(Exception): pass

# If flowtype chosen is default, instead use flow-style
# False except if meeting objects or arrays with more than
# this size of sub-elements
MAX_DEFAULT_NON_FLOW_ITEMS = 4

MODE_ACTION = '.action'


def rosaction_cmd_list(mode, full, argv=None):
    if argv is None:
        argv = sys.argv[1:]
    parser = OptionParser(usage="usage: ros%s list" % mode[1:])
    options, args = parser.parse_args(argv[1:])
    if mode == MODE_ACTION:
        subdir = 'action'
    else:
        raise ValueError('Unknown mode for iterate_packages: %s' % mode)

    rospack = rospkg.RosPack()
    packs = sorted([x for x in iterate_packages(rospack, mode)])
    for (p, direc) in packs:
        for file_ in _list_types(direc, subdir, mode):
            rospy.loginfo("%s/%s" % (p, file_))


def _get_action_class_genpy(type_str, message_type, reload_on_error=False):
    """
    Taken from genpy.message._get_message_or_service_class

    Utility for retrieving message/service class instances. Used by
    get_message_class and get_service_class.
    :param type_str: 'msg' or 'srv', ``str``
    :param message_type: type name of message/service, ``str``
    :returns: Message/Service  for message/service type or None, ``class``
    :raises: :exc:`ValueError` If message_type is invalidly specified
    """
    # # parse package and local type name for import
    package, base_type = genmsg.package_resource_name(message_type)
    if not package:
        if base_type == 'Header':
            package = 'std_msgs'
        else:
            raise ValueError("message type is missing package name: %s"
                             % str(message_type))
    pypkg = val = None
    try:
        # import the package and return the class
        pypkg = __import__('%s.%s' % (package, type_str))
        val = getattr(getattr(pypkg, type_str), base_type)
    except ImportError:
        val = None
    except AttributeError:
        val = None

"""
Taken from genpy.message
cache for get_message_class
"""
_message_class_cache_genpy = {}


def get_message_class_genpy(message_type, reload_on_error=False):
    """
    Taken from genpy.message.get_message_class

    Get the message class. NOTE: this function maintains a
    local cache of results to improve performance.
    :param message_type: type name of message, ``str``
    :param reload_on_error: (optional). Attempt to reload the Python
      module if unable to load message the first time. Defaults to
      False. This is necessary if messages are built after the first load.
    :returns: Message class for message/service type, ``Message class``
    :raises :exc:`ValueError`: if  message_type is invalidly specified
    """
    if message_type in _message_class_cache_genpy:
        return _message_class_cache_genpy[message_type]
    cls = _get_action_class_genpy('action', message_type,
                                  reload_on_error=reload_on_error)
    if cls:
        _message_class_cache_genpy[message_type] = cls
    return cls


def _get_action_class(type_str, message_type, reload_on_error=False):
    """
    Taken from roslib.message._get_message_or_service_class
    """

    # # parse package and local type name for import
    package, base_type = genmsg.package_resource_name(message_type)
    if not package:
        if base_type == 'Header':
            package = 'std_msgs'
        else:
            raise ValueError("message type is missing package name: %s" % 
                             str(message_type))
    pypkg = val = None
    try:
        # bootstrap our sys.path
        roslib.launcher.load_manifest(package)

        rospy.loginfo('package={} type_str={} base_type={}'.format(
                                         package, type_str, base_type))

        # import the package and return the class
        pypkg = __import__('%s/%s' % (package, type_str))
        # pypkg = __import__('%s.%s'%(package, type_str))
        val = getattr(getattr(pypkg, type_str), base_type)

    except rospkg.ResourceNotFound:
        val = None
        rospy.loginfo('_get_action_class except 1')
    except ImportError:
        val = None
        rospy.loginfo('_get_action_class except 2')
    except AttributeError:
        val = None
        rospy.loginfo('_get_action_class except 3')

    # this logic is mainly to support rosh, so that a user doesn't
    # have to exit a shell just because a message wasn't built yet
    if val is None and reload_on_error:
        try:
            if pypkg:
                reload(pypkg)
            val = getattr(getattr(pypkg, type_str), base_type)
        except:
            val = None
    return val

"""
Taken from roslib.message
"""
# # cache for get_message_class
_action_class_cache = {}


def get_action_class(action_type, reload_on_error=False):
    """
    Taken from roslib.message.get_action_class
    """

    if action_type in _action_class_cache:
        return _action_class_cache[action_type]
    # try w/o bootstrapping
    cls = get_message_class_genpy(action_type, reload_on_error=reload_on_error)
    if cls is None:
        # try old loader w/ bootstrapping
        cls = _get_action_class('action', action_type,
                                            reload_on_error=reload_on_error)
    if cls:
        _action_class_cache[action_type] = cls
    return cls


def iterate_packages(rospack, mode):
    """
    Iterator for packages that contain actions
    :param mode: .action, ``str``
    """
    if mode == MODE_ACTION:
        subdir = 'action'
    else:
        raise ValueError('Unknown mode for iterate_packages: %s' % mode)
    pkgs = rospack.list()
    for p in pkgs:
        d = os.path.join(rospack.get_path(p), subdir)
        if os.path.isdir(d):
            yield p, d


def _msg_filter(ext):
    def mfilter(f):
        """
        Predicate for filtering directory list. matches message files
        :param f: filename, ``str``
        """
        return os.path.isfile(f) and f.endswith(ext)
    return mfilter


def _list_resources(path, rfilter=os.path.isfile):
    """
    List resources in a package directory within a particular
    subdirectory. This is useful for listing messages, services, etc...
    :param rfilter: resource filter function that returns true if filename is
    the desired resource type, ``fn(filename)->bool``
    """
    resources = []
    if os.path.isdir(path):
        resources = [f for f in os.listdir(path) if rfilter(os.path.join(path, f))]
    else:
        resources = []
    return resources


def _list_types(path, subdir, ext):
    """
    List all messages in the specified package
    :param package str: name of package to search
    :param include_depends bool: if True, will also list messages in package
                                 dependencies
    :returns [str]: message type names
    """
    types = _list_resources(path, _msg_filter(ext))
    result = [x[:-len(ext)] for x in types]
    result.sort()

    rospy.loginfo('_list_types result={}'.format(result))

    return result


def list_types(package, mode=MODE_ACTION):
    """
    Lists msg/srvs contained in package
    :param package: package name, ``str``
    :param mode: MODE_ACTION. Defaults to msgs, ``str``
    :returns: list of msgs/srv in package, ``[str]``
    """

    rospack = rospkg.RosPack()
    if mode == MODE_ACTION:
        subdir = 'action'
    else:
        raise ValueError('Unknown mode for list_types: %s' % mode)
    path = os.path.join(rospack.get_path(package), subdir)

    rospy.loginfo('list_types package={} mode={} path={}'.format(package, mode,
                                                                 path))

    return [genmsg.resource_name(package, t)
            for t in _list_types(path, subdir, mode)]


def list_actions(package):
    """
    List actions contained in package
    :param package: package name, ``str``
    :returns: list of actions in package, ``[str]``
    """
    return list_types(package, mode=MODE_ACTION)


def rosactionmain(mode=MODE_ACTION):
    """
    Main entry point for command-line tools (rosaction).

    rosaction can interact with either ros messages or ros services. The mode
    param indicates which
    :param mode: MODE_ACTION or MODE_SRV, ``str``
    """
    try:
        if mode == MODE_ACTION:
            ext, full = mode, "message type"
        else:
            raise ROSActionException("Invalid mode: %s" % mode)

        if len(sys.argv) == 1:
            rospy.loginfo(fullusage('ros' + mode[1:]))
            sys.exit(0)

        command = sys.argv[1]
#        if command == 'show':
#            rosaction_cmd_show(ext, full)
#        elif command == 'package':
#            rosaction_cmd_package(ext, full)
#        elif command == 'packages':
#            rosaction_cmd_packages(ext, full)
        if command == 'list':
            rosaction_cmd_list(ext, full)
#        elif command == 'md5':
#            rosaction_cmd_md5(ext, full)
        elif command == '--help':
            print(fullusage('ros' + mode[1:]))
            sys.exit(0)
        else:
            print(fullusage('ros' + mode[1:]))
            sys.exit(getattr(os, 'EX_USAGE', 1))
    except KeyError as e:
        print("Unknown message type: %s" % e, file=sys.stderr)
        sys.exit(getattr(os, 'EX_USAGE', 1))
    except rospkg.ResourceNotFound as e:
        print("Invalid package: %s" % e, file=sys.stderr)
        sys.exit(getattr(os, 'EX_USAGE', 1))
    except ValueError as e:
        print("Invalid type: '%s'" % e, file=sys.stderr)
        sys.exit(getattr(os, 'EX_USAGE', 1))
    except ROSActionException as e:
        print(str(e), file=sys.stderr)
        sys.exit(1)
    except KeyboardInterrupt:
        pass

"""
"#NOT_TESTED_FROM_HERE"----------------------------------------
From here are what are copied from __init__.py that I don't know yet
if they are necessary/useful.
"""
 ## copied from the web, recipe for ordered yaml output ######
def construct_ordered_mapping(self, node, deep=False):
    if not isinstance(node, yaml.MappingNode):
        raise yaml.constructor.ConstructorError(None, None,
                "expected a mapping node, but found %s" % node.id,
                node.start_mark)
    mapping = collections.OrderedDict()
    for key_node, value_node in node.value:
        key = self.construct_object(key_node, deep=deep)
        if not isinstance(key, collections.Hashable):
            raise yaml.constructor.ConstructorError("while constructing a mapping",
                                                    node.start_mark,
                    "found unhashable key", key_node.start_mark)
        value = self.construct_object(value_node, deep=deep)
        mapping[key] = value
    return mapping

def construct_yaml_map_with_ordered_dict(self, node):
    data = collections.OrderedDict()
    yield data
    value = self.construct_mapping(node)
    data.update(value)

def represent_ordered_mapping(self, tag, mapping, flow_style=None):
    value = []
    node = yaml.MappingNode(tag, value, flow_style=flow_style)
    if self.alias_key is not None:
        self.represented_objects[self.alias_key] = node
    best_style = True
    if hasattr(mapping, 'items'):
        mapping = list(mapping.items())
    for item_key, item_value in mapping:
        node_key = self.represent_data(item_key)
        node_value = self.represent_data(item_value)
        if not (isinstance(node_key, yaml.ScalarNode) and not node_key.style):
            best_style = False
        if not (isinstance(node_value, yaml.ScalarNode) and not node_value.style):
            best_style = False
        value.append((node_key, node_value))
    if flow_style is None:
        if self.default_flow_style is not None:
            node.flow_style = self.default_flow_style
        else:
            node.flow_style = best_style
    return node

## end recipe for ordered yaml output ######


def get_array_type_instance(field_type, default_package=None):
    """
    returns a single instance of field_type, where field_type can be a
    message or ros primitive or an flexible size array.
    """
    field_type = field_type.strip().rstrip("[]")
    if field_type == "empty":
        return None
    if not "/" in field_type:
        # is either built-in, Header, or in same package
        # it seems built-in types get a priority
        if field_type in ['byte', 'int8', 'int16', 'int32', 'int64', \
                          'char', 'uint8', 'uint16', 'uint32', 'uint64']:
            return 0
        elif field_type in ['float32', 'float64']:
            return 0
        elif field_type in ['string']:
            return ""
        elif field_type == 'bool':
            return False
        elif field_type == 'time':
            field_type = "std_msgs/Time"
        elif field_type == 'duration':
            field_type = "std_msgs/Duration"
        elif field_type == 'Header':
            field_type = "std_msgs/Header"
        else:
            if default_package is None:
                return None
            field_type = default_package + "/" + field_type
    msg_class = roslib.message.get_message_class(field_type)
    if (msg_class == None):
        # not important enough to raise exception?
        return None
    instance = msg_class()
    return instance

def get_yaml_for_msg(msg, prefix='', time_offset=None, current_time=None,
                     field_filter=None, flow_style_=None, fill_arrays_=False):
    """
    Builds a YAML string of message.
    @param msg: A object, dict or array
    @param flow_style_: if True, produces one line with brackets, if false uses multiple lines with indentation, if None uses both using heuristics
    @param prefix: prefixes all lines with this string
    @param fill_arrays_: if True, for all flexible size arrays an element will be generated
    @param current_time: currently not used. Only provided for API compatibility. current_time passes in the current time with respect to the message.
    @type  current_time: Time
    @param field_filter: filter the fields that are strified for Messages.
    @type  field_filter: fn(Message)->iter(str)
    @type  flow_style_: bool
    @return: a string
    """
    def object_representer(dumper, obj):
        ndict = collections.OrderedDict()
        index = 0
        # allow caller to select which fields of message are strified
        if field_filter != None:
            fields = list(field_filter(obj))
        else:
            fields = obj.__slots__
        for key in fields:
            if not key.startswith('_'):
                val = getattr(obj, key)
                if type(val) == list and len(val) > MAX_DEFAULT_NON_FLOW_ITEMS:
                     dumper.default_flow_style = flow_style_
                if time_offset is not None and isinstance(val, Time):
                    ndict[key] = val - time_offset
                # create initial array element (e.g. for code completion)
                elif fill_arrays_ == True and val == []:
                    message_type = obj._slot_types[index]
                    if (obj._type != None) and "/" in obj._type:
                        def_pack = obj._type.split("/")[0]
                        instance = get_array_type_instance(message_type, default_package=def_pack)
                    if instance == None:
                        # not important enough to raise exception?
                        ndict[key] = val
                    else:
                        ndict[key] = [instance]
                elif not inspect.ismethod(val) and not inspect.isfunction(val):
                    ndict[key] = val
            index += 1
        # as a hack, we improve the heuristics of pyyaml and say with less than 5 objects, no need for brackets
        if len(ndict) > MAX_DEFAULT_NON_FLOW_ITEMS:
            dumper.default_flow_style = flow_style_
        return dumper.represent_dict(ndict)
    yaml.representer.SafeRepresenter.add_representer(None, object_representer)

     # we force False over None here and set the style in dumper, to
     # avoid unecessary outer brackets pyyaml chooses e.g. to
     # represent msg Int32 as "{data: 0}"
    initial_flow_style = False
    if flow_style_ == True:
        initial_flow_style = True

    # need to set default flow style True for bash prototype
    # means will generate one line with [] and {} brackets
    # bash needs bracket notation for rostopic pub
    txt = yaml.safe_dump(msg,
                         # None, True, False (None chooses a compromise)
                         default_flow_style=initial_flow_style,
                         # Can be None, '', '\'', '"', '|', '>'.
                         default_style='',
                         # indent=2, #>=2, indentation depth
                         # line_break=?,
                         # allow_unicode=?,
                         # if true writes plenty of tags
                         # canonical = False,
                         # version={}?,
                         # width=40,
                         # encoding=?,
                         # tags={}?,
                         # when True, produces --- at start
                         # explicit_start=False,
                         # when True, produces ... at end
                         # explicit_end=False
                         )
    if prefix != None and prefix != '':
        result = prefix + ("\n" + prefix).join(txt.splitlines())
    else:
        result = txt.rstrip('\n')
    return result


def create_names_filter(names):
    """
    returns a function to use as filter that returns all objects slots except those with names in list.
    """
    return lambda obj : filter(lambda slotname : not slotname in names, obj.__slots__)


def init_rosaction_proto():
    if "OrderedDict" in collections.__dict__:
        yaml.constructor.BaseConstructor.construct_mapping = construct_ordered_mapping
        yaml.constructor.Constructor.add_constructor(
            'tag:yaml.org,2002:map',
            construct_yaml_map_with_ordered_dict)

        yaml.representer.BaseRepresenter.represent_mapping = represent_ordered_mapping
        yaml.representer.Representer.add_representer(collections.OrderedDict,
                                                     yaml.representer.SafeRepresenter.represent_dict)
    
def rosaction_cmd_prototype(args):
    init_rosaction_proto()
    parser = OptionParser(usage="usage: rosactionproto msg/srv [options]",
                          description="Produces output or a msg or service request, intended for tab completion support.")
    parser.add_option("-f", "--flow_style",
                      dest="flow_style", type="int", default=None, action="store",
                      help="if 1 always use brackets, if 0 never use brackets. Default is a heuristic mix.")
    parser.add_option("-e", "--empty-arrays",
                      dest="empty_arrays", default=False, action="store_true",
                      help="if true flexible size arrays are not filled with default instance")
    parser.add_option("-s", "--silent",
                      dest="silent", default=False, action="store_true",
                      help="if true supresses all error messages")
    parser.add_option("-p", "--prefix", metavar="prefix", default="",
                      help="prefix to print before each line, can be used for indent")
    parser.add_option("-H", "--no-hyphens",
                      dest="no_hyphens", default="", action="store_true",
                      help="if true output has no outer hyphens")
    parser.add_option("-x", "--exclude-slots", metavar="exclude_slots", default="",
                      help="comma separated list of slot names not to print")

    options, args = parser.parse_args(args)

    try:
        if len(args) < 2:
            raise RosActionProtoArgsException("Insufficient arguments")
        mode = ".%s" % args[0]
        message_type = args[1]
        field_filter = None
        if options.exclude_slots != None and options.exclude_slots.strip() != "":
            field_filter = create_names_filter(options.exclude_slots.split(','))
    
        # possible extentions: options for
        # - target language
        # - initial values for standard types
        # - get partial message (subtree)

        # try to catch the user specifying code-style types and error
        if '::' in message_type:
            if not options.silent:
                parser.error("rosactionproto does not understand C++-style namespaces (i.e. '::').\nPlease refer to msg/srv types as 'package_name/Type'.")
        elif '.' in message_type:
            if not options.silent:
                parser.error("invalid message type '%s'.\nPlease refer to msg/srv types as 'package_name/Type'." % message_type)
        if not '/' in message_type:
            # if only one such msg or srv exists, use it
            results = []
            for found in rosaction_search(rospkg.RosPack(), mode, message_type):
                results.append(found)
            if len(results) > 1:
                raise ROSActionProtoException("Ambiguous message name %s" % message_type)
            elif len(results) < 1:
                raise ROSActionProtoException("Unknown message name %s" % message_type)
            else:
                message_type = results[0]
    
        if mode == MODE_ACTION:
            msg_class = roslib.message.get_message_class(message_type)
            if (msg_class == None):
                raise ROSActionProtoException("Unknown message class: %s" % message_type)
            instance = msg_class()
        else:
            raise ROSActionProtoException("Invalid mode: %s" % mode)
        txt = get_yaml_for_msg(instance,
                               prefix=options.prefix,
                               flow_style_=options.flow_style,
                               fill_arrays_=not options.empty_arrays,
                               field_filter=field_filter)

        if options.no_hyphens == True:
            return txt
        else:
            return '"' + txt + '"'

    except KeyError as e:
        if not options.silent:
            sys.stderr.write("Unknown message type: %s" % e, file=sys.stderr)
            sys.exit(getattr(os, 'EX_USAGE', 1))
    # except rospkg.InvalidROSPkgException as e:
    #     if not options.silent:
    #         print(file=sys.stderr, "Invalid package: '%s'"%e)
    #         sys.exit(getattr(os, 'EX_USAGE', 1))
    except ValueError as e:
        if not options.silent:
            sys.stderr.write("Invalid type: '%s'" % e)
            sys.exit(getattr(os, 'EX_USAGE', 1))
    except ROSActionProtoException as e:
        if not options.silent:
            sys.stderr.write(str(e))
            sys.exit(1)
    except RosActionProtoArgsException as e:
        if not options.silent:
            sys.stderr.write("%s" % e)
            sys.exit(getattr(os, 'EX_USAGE', 1))
    except KeyboardInterrupt:
        pass

#### Start of rosmsg ####

try:
    from cStringIO import StringIO  # Python 2.x
except ImportError:
    from io import StringIO  # Python 3.x
def spec_to_str(action_context, spec, buff=None, indent=''):
    """
    Convert spec into a string representation. Helper routine for MsgSpec.
    :param indent: internal use only, ``str``
    :param buff: internal use only, ``StringIO``
    :returns: string representation of spec, ``str``
    """
    if buff is None:
        buff = StringIO()
    for c in spec.constants:
        buff.write("%s%s %s=%s\n" % (indent, c.type, c.name, c.val_text))
    for type_, name in zip(spec.types, spec.names):
        buff.write("%s%s %s\n" % (indent, type_, name))
        base_type = genmsg.msgs.bare_msg_type(type_)
        if not base_type in genmsg.msgs.BUILTIN_TYPES:
            subspec = msg_context.get_registered(base_type)
            spec_to_str(msg_context, subspec, buff, indent + '  ')
    return buff.getvalue()

def get_msg_text(type_, raw=False, rospack=None):
    """
    Get .msg file for type_ as text
    :param type_: message type, ``str``
    :param raw: if True, include comments and whitespace (default False), ``bool``
    :returns: text of .msg file, ``str``
    :raises :exc:`ROSActionException` If type_ is unknown
    """
    if rospack is None:
        rospack = rospkg.RosPack()
    search_path = {}
    for p in rospack.list():
        search_path[p] = [os.path.join(rospack.get_path(p), 'msg')]

    context = genmsg.MsgContext.create_default()
    try:
        spec = genmsg.load_msg_by_type(context, type_, search_path)
        genmsg.load_depends(context, spec, search_path)
    except Exception as e:
        raise ROSActionException("Unable to load msg [%s]: %s" % (type_, e))
    
    if raw:
        return spec.text
    else:
        return spec_to_str(context, spec)

def _msg_filter(ext):
    def mfilter(f):
        """
        Predicate for filtering directory list. matches message files
        :param f: filename, ``str``
        """
        return os.path.isfile(f) and f.endswith(ext)
    return mfilter


def rosaction_search(rospack, mode, base_type):
    """
    Iterator for all packages that contain a message matching base_type

    :param base_type: message base type to match, e.g. 'String' would match std_msgs/String, ``str``
    """
    for p, path in iterate_packages(rospack, mode):
        if os.path.isfile(os.path.join(path, "%s%s" % (base_type, mode))):
            yield genmsg.resource_name(p, base_type)

def _stdin_arg(parser, full):
    options, args = parser.parse_args(sys.argv[2:])    
    # read in args from stdin pipe if not present
    if not args:
        arg = None
        while not arg:
            arg = sys.stdin.readline().strip()
        return options, arg
    else:
        if len(args) > 1:
            parser.error("you may only specify one %s" % full)
        return options, args[0]
    
def rosaction_cmd_show(mode, full):
    cmd = "ros%s" % (mode[1:])
    parser = OptionParser(usage="usage: %s show [options] <%s>" % (cmd, full))
    parser.add_option("-r", "--raw",
                      dest="raw", default=False, action="store_true",
                      help="show raw message text, including comments")
    parser.add_option("-b", "--bag",
                      dest="bag", default=None,
                      help="show message from .bag file", metavar="BAGFILE")
    options, arg = _stdin_arg(parser, full)
    if arg.endswith(mode):
        arg = arg[:-(len(mode))]

    # try to catch the user specifying code-style types and error
    if '::' in arg:
        parser.error(cmd + " does not understand C++-style namespaces (i.e. '::').\nPlease refer to msg/srv types as 'package_name/Type'.")
    elif '.' in arg:
        parser.error("invalid message type '%s'.\nPlease refer to msg/srv types as 'package_name/Type'." % arg)
    if options.bag:
        bag_file = options.bag
        if not os.path.exists(bag_file):
            raise ROSActionException("ERROR: bag file [%s] does not exist" % bag_file)
        for topic, msg, t in rosbag.Bag(bag_file).read_messages(raw=True):
            datatype, _, _, _, pytype = msg
            if datatype == arg:
                print(get_msg_text(datatype, options.raw, pytype._full_text))
                break
    else:
        rospack = rospkg.RosPack()
        if '/' in arg:  # package specified
            rosaction_debug(rospack, mode, arg, options.raw)
        else:
            for found in rosaction_search(rospack, mode, arg):
                print("[%s]:" % found)
                rosaction_debug(rospack, mode, found, options.raw)

def rosaction_md5(mode, type_):
    try:
        if mode == MODE_ACTION:
            msg_class = roslib.message.get_message_class(type_)
        else:
            msg_class = roslib.message.get_service_class(type_)            
    except ImportError:
        raise IOError("cannot load [%s]" % (type_))
    if msg_class is not None:
        return msg_class._md5sum
    else:
        raise IOError("cannot load [%s]" % (type_))        
    
def rosaction_cmd_md5(mode, full):
    parser = OptionParser(usage="usage: ros%s md5 <%s>" % (mode[1:], full))
    options, arg = _stdin_arg(parser, full)

    if '/' in arg:  # package specified
        try:
            md5 = rosaction_md5(mode, arg)
            print(md5)
        except IOError:
            print("Cannot locate [%s]" % arg, file=sys.stderr)
    else:
        rospack = rospkg.RosPack()
        matches = [m for m in rosaction_search(rospack, mode, arg)]
        for found in matches:
            try:
                md5 = rosaction_md5(mode, found)
                print("[%s]: %s" % (found, md5))
            except IOError:
                print("Cannot locate [%s]" % found, file=sys.stderr)
        if not matches:
            print("No messages matching the name [%s]" % arg, file=sys.stderr)
                
def rosaction_cmd_package(mode, full):
    parser = OptionParser(usage="usage: ros%s package <package>" % mode[1:])
    parser.add_option("-s",
                      dest="single_line", default=False, action="store_true",
                      help="list all msgs on a single line")
    options, arg = _stdin_arg(parser, full)
    joinstring = '\n'
    if options.single_line:
        joinstring = ' '
    print(joinstring.join(list_types(arg, mode=mode)))
    
def rosaction_cmd_packages(mode, full, argv=None):
    if argv is None:
        argv = sys.argv[1:]
    parser = OptionParser(usage="usage: ros%s packages" % mode[1:])
    parser.add_option("-s",
                      dest="single_line", default=False, action="store_true",
                      help="list all packages on a single line")
    options, args = parser.parse_args(argv[1:])
    rospack = rospkg.RosPack()
    joinstring = '\n'
    if options.single_line:
        joinstring = ' '
    p1 = [p for p, _ in iterate_packages(rospack, mode)]
    p1.sort()
    print(joinstring.join(p1))

def rosaction_debug(rospack, mode, type_, raw=False):
    """
    Prints contents of msg/srv file
    :param mode: MODE_ACTION or MODE_SRV, ``str``
    """
    if mode == MODE_ACTION:
        print(get_msg_text(type_, raw=raw, rospack=rospack))
    else:
        raise ROSActionException("Invalid mode for debug: %s" % mode)