Support "scope" for machine tag default semantics

Proposed fix for ros#1884

tools/roslaunch/src/roslaunch/loader.py

@@ -155,7 +155,8 @@ class LoaderContext(object):
     """
 
     def __init__(self, ns, filename, parent=None, params=None, env_args=None, \
-                     resolve_dict=None, include_resolve_dict=None, arg_names=None):
+                     resolve_dict=None, include_resolve_dict=None, arg_names=None, \
+                     default_machine=None):
         """
         @param ns: namespace
         @type  ns: str
@@ -169,6 +170,9 @@ def __init__(self, ns, filename, parent=None, params=None, env_args=None, \
         @type include_resolve_dict: dict
         @param arg_names: name of args that have been declared in this context
         @type  arg_names: [str]
+        @param default_machine: name of the machine to use as default only
+        within this context.
+        @type  default_machine: str
         """
         self.parent = parent
         self.ns = make_global_ns(ns or '/')
@@ -184,6 +188,8 @@ def __init__(self, ns, filename, parent=None, params=None, env_args=None, \
         self.include_resolve_dict = include_resolve_dict or None
         # when this context was created via include, was pass_all_args set?
         self.pass_all_args = False
+        # default machine to use for nodes defined later in this context
+        self.default_machine = default_machine
 
     def add_param(self, p):
         """
@@ -323,8 +329,9 @@ def child(self, ns):
         return LoaderContext(child_ns, self.filename, parent=self,
                              params=self.params, env_args=self.env_args[:],
                              resolve_dict=deepcopy(self.resolve_dict),
-                             arg_names=self.arg_names[:], include_resolve_dict=self.include_resolve_dict)
-
+                             arg_names=self.arg_names[:], include_resolve_dict=self.include_resolve_dict,
+                             default_machine=self.default_machine)
+
 #TODO: in-progress refactorization. I'm slowly separating out
 #non-XML-specific logic from xmlloader and moving into Loader. Soon
 #this will mean that it will be easier to write coverage tests for

tools/roslaunch/src/roslaunch/xmlloader.py

@@ -153,9 +153,12 @@ def _float_attr(v, default, label):
 
 
 # maps machine 'default' attribute to Machine default property
-_is_default = {'true': True, 'false': False, 'never': False }
+_is_default = {'true': True, 'scope': False, 'false': False, 'never': False }
 # maps machine 'default' attribute to Machine assignable property
-_assignable = {'true': True, 'false': True, 'never': False }
+_assignable = {'true': True, 'scope': True, 'false': True, 'never': False }
+# maps machine 'default' attribute to whether this sets the default_machine in
+# the loader context
+_is_context_default = {'true': True, 'scope': True, 'false': False, 'never': False }
 
 # NOTE: code is currently in a semi-refactored state. I'm slowly
 # migrating common routines into the Loader class in the hopes it will
@@ -388,8 +391,11 @@ def _node_tag(self, tag, context, ros_config, default_machine, is_test=False, ve
                     required = self.opt_attrs(tag, context, ('machine', 'args',
                         'output', 'respawn', 'respawn_delay', 'cwd',
                         'launch-prefix', 'required'))
-            if not machine and default_machine:
-                machine = default_machine.name
+            if not machine:
+                if context.default_machine:
+                    machine = context.default_machine.name
+                elif default_machine:
+                    machine = default_machine.name
             # validate respawn, required
             required, respawn = [_bool_attr(*rr) for rr in ((required, False, 'required'),\
                                                                 (respawn, False, 'respawn'))]
@@ -484,8 +490,12 @@ def _machine_tag(self, tag, context, ros_config, verbose=True):
             try:
                 assignable = _assignable[default]
                 is_default = _is_default[default]
+                is_context_default = _is_context_default[default]
             except KeyError as e:
                 raise XmlParseException("Invalid value for 'attribute': %s"%default)
+            # if the default tag is 'scope' set the default_machine for the current context
+            if is_context_default:
+                context.parent.default_machine = m
 
             # load env args
             for t in [c for c in tag.childNodes if c.nodeType == DomNode.ELEMENT_NODE]:

tools/roslaunch/test/unit/test_xmlloader.py

@@ -636,7 +636,14 @@ def test_machines(self):
             elif m.name == 'machine9':
                 self.assertEquals(m.env_loader, '/opt/ros/fuerte/env.sh')
 
-
+    def test_scoped_machine(self):
+        test_file = os.path.join(self.xml_dir, 'test-machine-scoped.xml')
+        mock = self._load(test_file)
+        expect_nodes = {'n1': 'machine2', 'n2': 'machine1'}
+        self.assertEquals(len(mock.nodes), len(expect_nodes))
+        for node in mock.nodes:
+            self.assertEquals(node.machine_name, expect_nodes[node.name])
+
     def test_node_subst(self):
         test_file =os.path.join(self.xml_dir, 'test-node-substitution.xml')
         keys = ['PACKAGE', 'TYPE', 'OUTPUT', 'RESPAWN']

tools/roslaunch/test/xml/test-machine-scoped.xml

@@ -0,0 +1,11 @@
+<launch>
+  <machine name="machine1" address="address1" default="true" />
+
+  <group>
+    <machine name="machine2" address="address2" default="scope" />
+    <node name="n1" pkg="pack1" type="foo_node" />  <!-- machine2 -->
+  </group>
+
+  <node name="n2" pkg="pack2" type="bar_node" />  <!-- machine1 -->
+
+</launch>