resources.py

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#
# License: BSD
#   https://raw.github.com/robotics-in-concert/rocon_tools/license/LICENSE
#

##############################################################################
# Imports
##############################################################################

# system
import os

# ros
import rospkg
import roslib.names

from .catkin import package_index_from_package_path

##############################################################################
# Resources
##############################################################################


def find_resource_from_string(resource, rospack=None, extension=None):
    '''
      Convenience wrapper around roslib to find a resource (file) inside
      a package. This function passes off the work to find_resource
      once the input string is split.

      @param package : ros package
      @param resource : string resource identifier of the form package/filename

      @param extension : file name extension to look for/expect
      @type string

      @return full pathname to the resource
      @rtype str

      @raise rospkg.ResourceNotFound : raised if the resource is not found or has an inappropriate extension.
    '''
    if extension is not None:
        filename_extension = os.path.splitext(resource)[-1]
        if filename_extension == '':  # no ext given
            resource += ".%s" % extension
        elif filename_extension != "." + extension and filename_extension != extension:
            raise rospkg.ResourceNotFound("resource with invalid filename extension specified [%s][%s]" % (resource, extension))
    package, filename = roslib.names.package_resource_name(resource)
    if not package:
        raise rospkg.ResourceNotFound("resource could not be split with a valid leading package name [%s]" % (resource))
    return find_resource(package, filename, rospack)


def find_resource(package, filename, rospack=None):
    '''
      Convenience wrapper around roslib to find a resource (file) inside
      a package. It checks the output, and provides the appropriate
      error if there is one.

      @param package : ros package
      @param filename : some file inside the specified package
      @return str : absolute path to the file

      @raise rospkg.ResourceNotFound : raised if there is nothing found or multiple objects found.
    '''
    try:
        resolved = roslib.packages.find_resource(package, filename, rospack=rospack)
        if not resolved:
            raise rospkg.ResourceNotFound("cannot locate [%s] in package [%s]" % (filename, package))
        elif len(resolved) == 1:
            return resolved[0]
        elif len(resolved) > 1:
            raise rospkg.ResourceNotFound("multiple resources named [%s] in package [%s]:%s\nPlease specify full path instead" % (filename, package, ''.join(['\n- %s' % r for r in resolved])))
    except rospkg.ResourceNotFound:
        raise rospkg.ResourceNotFound("[%s] is not a package or launch file name [%s]" % (package, package + '/' + filename))
    return None


def resource_index_from_package_exports(export_tag, package_paths=None, package_whitelist=None, package_blacklist=[]):
    '''
      Scans the package path looking for exports and grab the ones we are interested in.

      @param export_tag : export tagname
      @type str

      @return the dictionary of resource and its absolute path
      @type { resource_name : os.path }
    '''
    package_index = _get_package_index(package_paths)
    resources = {}
    invalid_resources = {}
    for package in package_index.values():

        if package_whitelist:
            if package.name not in package_whitelist:
                continue
        elif package.name in package_blacklist:
            continue
        for export in package.exports:
            if export.tagname == export_tag:
                filename_relative_path = export.content
                resource_name = package.name + '/' + os.path.splitext(os.path.basename(filename_relative_path))[0]
                resource_filename = os.path.join(os.path.dirname(package.filename), filename_relative_path)
                if not os.path.isfile(resource_filename):
                    invalid_resources[resource_name] = resource_filename
                else:
                    resources[resource_name] = (resource_filename, package)
    return (resources, invalid_resources)


def _get_package_index(package_paths):
    # should make use of rospkg.get_ros_paths here.
    # http://docs.ros.org/independent/api/rospkg/html/rospkg_environment.html
    ros_package_path = package_paths if package_paths else os.getenv('ROS_PACKAGE_PATH', '')
    ros_package_path = [x for x in ros_package_path.split(':') if x]
    package_index = package_index_from_package_path(ros_package_path)
    return package_index