Add support for argNpath in add_signal_receiver

Match messages whose n´th argument equals the given value or match in a
path-like manner.

Signed-off-by: Jeroen Hofstee <jhofstee@victronenergy.com>

2 files changed, 56 insertions, 6 deletions

diff --git a/dbus/connection.py b/dbus/connection.py
index 621e54b..2bada4b 100644
--- a/dbus/connection.py
+++ b/dbus/connection.py
@@ -26,6 +26,7 @@ __all__ = ('Connection', 'SignalMatch')
 __docformat__ = 'reStructuredText'
 
 import logging
+import re
 import threading
 import weakref
 
@@ -39,7 +40,7 @@ from dbus.lowlevel import (
 from dbus.proxies import ProxyObject
 from dbus._compat import is_py2, is_py3
 
-from _dbus_bindings import String
+from _dbus_bindings import (ObjectPath, String)
 
 
 _logger = logging.getLogger('dbus.connection')
@@ -56,7 +57,7 @@ class SignalMatch(object):
               '_destination_keyword', '_interface_keyword',
               '_message_keyword', '_member_keyword',
               '_sender_keyword', '_path_keyword', '_int_args_match',
-              '_arg0namespace'
+              '_arg0namespace', '_int_args_paths'
               ]
 
     __slots__ = tuple(_slots)
@@ -103,21 +104,30 @@ class SignalMatch(object):
         self._args_match = kwargs
         if not kwargs:
             self._int_args_match = None
+            self._int_args_paths = None
         else:
             self._int_args_match = {}
+            self._int_args_paths = {}
             for kwarg in kwargs:
-                if not kwarg.startswith('arg'):
+                match = re.match("arg(\d+)(\w+)?$", kwarg)
+                if not match:
                     raise TypeError('SignalMatch: unknown keyword argument %s'
                                     % kwarg)
                 try:
-                    index = int(kwarg[3:])
+                    index = int(match[1])
                 except ValueError:
                     raise TypeError('SignalMatch: unknown keyword argument %s'
                                     % kwarg)
                 if index < 0 or index > 63:
                     raise TypeError('SignalMatch: arg match index must be in '
                                     'range(64), not %d' % index)
-                self._int_args_match[index] = kwargs[kwarg]
+                if match[2] is None:
+                    self._int_args_match[index] = kwargs[kwarg]
+                elif match[2] == "path":
+                    self._int_args_paths[index] = kwargs[kwarg]
+                else:
+                    raise TypeError('SignalMatch: unknown keyword argument %s'
+                                    % kwarg)
 
     def __hash__(self):
         """SignalMatch objects are compared by identity."""
@@ -149,6 +159,9 @@ class SignalMatch(object):
             if self._int_args_match is not None:
                 for index, value in self._int_args_match.items():
                     rule.append("arg%d='%s'" % (index, value))
+            if self._int_args_paths is not None:
+                for index, value in self._int_args_paths.items():
+                    rule.append("arg%dpath='%s'" % (index, value))
 
             self._rule = ','.join(rule)
 
@@ -183,7 +196,7 @@ class SignalMatch(object):
         # these haven't been checked yet by the match tree
         if self._sender_name_owner not in (None, message.get_sender()):
             return False
-        if self._int_args_match is not None:
+        if self._int_args_match is not None or self._int_args_paths is not None:
             # extracting args with byte_arrays is less work
             kwargs = dict(byte_arrays=True)
             args = message.get_args_list(**kwargs)
@@ -192,6 +205,23 @@ class SignalMatch(object):
                     or not isinstance(args[index], String)
                     or args[index] != value):
                     return False
+
+            if self._int_args_paths is not None:
+                for index, value in self._int_args_paths.items():
+                    if index >= len(args):
+                        return False
+
+                    arg = args[index]
+                    if not isinstance(arg, String) and not isinstance(arg, ObjectPath):
+                        return False
+
+                    if not (
+                                value == arg or
+                                value[-1:] == "/" and arg.startswith(value) or
+                                arg[-1:] == "/" and value.startswith(arg)
+                            ):
+                        return False
+
         if self._arg0namespace is not None:
             kwargs = dict(byte_arrays=True)
             args = message.get_args_list(**kwargs)
@@ -402,6 +432,16 @@ class Connection(_Connection):
                 argument is a string that either is equal to the
                 keyword parameter, or starts with the keyword parameter
                 followed by a dot (and optionally more text).
+            `arg...path`: str
+                If there are additional keyword parameters of the form
+                ``arg``\\ *n* ``path``, match only signals where the *n*\\ th
+                argument is either equal or matches in a path like manner.
+                A path-like comparison matches when either the keyword or the
+                argument ends with a '/' and is a prefix of the other. An
+                example argument path match is arg0path='/aa/bb/'. This would
+                match messages with first arguments of '/', '/aa/', '/aa/bb/',
+                '/aa/bb/cc/' and '/aa/bb/cc'. It would not match messages with
+                first arguments of '/aa/b', '/aa' or even '/aa/bb'.
             `named_service` : str
                 A deprecated alias for `bus_name`.
         """
diff --git a/dbus/proxies.py b/dbus/proxies.py
index a31b5ea..523399e 100644
--- a/dbus/proxies.py
+++ b/dbus/proxies.py
@@ -366,6 +366,16 @@ class ProxyObject(object):
                 argument is a string that either is equal to the
                 keyword parameter, or starts with the keyword parameter
                 followed by a dot (and optionally more text).
+            `arg...path`: str
+                If there are additional keyword parameters of the form
+                ``arg``\\ *n* ``path``, match only signals where the *n*\\ th
+                argument is either equal or matches in a path-like manner.
+                A path-like comparison matches when either the keyword or the
+                argument ends with a '/' and is a prefix of the other. An
+                example argument path match is arg0path='/aa/bb/'. This would
+                match messages with first arguments of '/', '/aa/', '/aa/bb/',
+                '/aa/bb/cc/' and '/aa/bb/cc'. It would not match messages with
+                first arguments of '/aa/b', '/aa' or even '/aa/bb'.
         """
         return \
         self._bus.add_signal_receiver(handler_function,