ThrottledDevice: speed up quick reactivation

[~helmut/onoff.git] / onoff / dbusutils.py

diff --git a/onoff/dbusutils.py b/onoff/dbusutils.py
index 1305917..c248ed5 100644 (file)
--- a/onoff/dbusutils.py
+++ b/onoff/dbusutils.py
@@ -1,29 +1,146 @@
 import argparse
+import logging
+import socket
+import xml.parsers.expat
 
 import dbus
+import dbus.service
+from gi.repository import GObject
+
+logger = logging.getLogger("onoff.dbusutils")
 
 object_prefix = "/de/subdivi/onoff0"
+default_busname = "de.subdivi.onoff0"
 
 dbus_options = argparse.ArgumentParser(add_help=False)
 dbus_options.add_argument("--bus", default="session",
                           choices=("system", "session"),
                           help="which bus to use (default: %(default)s)")
-dbus_options.add_argument("--busname", type=str, required=True,
-                          help="which busname (i.e. client) to use")
-dbus_options.add_argument("--device", type=str, required=True,
+dbus_options.add_argument("--busname", type=str, default=default_busname,
+                          help="which busname (i.e. client) to use " +
+                               "(default: %(default)s)")
+dbus_options.add_argument("--device", type=str,
                           help="which device to control")
 
-def get_dbus_proxy(namespace):
+def get_dbus(namespace):
     """
     @param namespace: a namespace returned from a dbus_options argument parser
-    @returns: a dbus object proxy
+    @rtype: dbus.Bus
+    @returns: the requested bus
     """
     if namespace.bus == "session":
-        bus = dbus.SessionBus()
+        return dbus.SessionBus()
     elif namespace.bus == "system":
-        bus = dbus.SystemBus()
+        return dbus.SystemBus()
     else:
         raise AssertionError("namespace.bus %r is neither session nor system",
                              namespace.bus)
+
+def get_dbus_proxy(namespace):
+    """
+    @param namespace: a namespace returned from a dbus_options argument parser
+    @returns: a dbus object proxy
+    """
+    bus = get_dbus(namespace)
+    if not namespace.device:
+        raise ValueError("no --device given")
     objname = "%s/%s" % (object_prefix, namespace.device)
     return bus.get_object(namespace.busname, objname)
+
+def socketpair():
+    """Create a socket pair where the latter end is already wrapped for
+    transmission over dbus.
+
+    @rtype: (socket, dbus.types.UnixFd)
+    """
+    s1, s2 = socket.socketpair()
+    s3 = dbus.types.UnixFd(s2)
+    s2.close()
+    return s1, s3
+
+def list_objects(bus, busname, path=None):
+    """List objects on the given bus and busname starting with path. Only the
+    trailing components after the slash are returned.
+
+    @type bus: dbus.Bus
+    @type busname: str
+    @type path: None or str
+    @param path: prefix for searching objects. Defaults to
+        dbusutils.object_prefix.
+    @rtype: [str]
+    @returns: the trailing components of the objects found
+    """
+    if path is None:
+        path = object_prefix
+    xmlstring = bus.get_object(busname, path).Introspect()
+    parser = xml.parsers.expat.ParserCreate()
+    nodes = []
+    def start_element(name, attrs):
+        if name != "node":
+            return
+        try:
+            value = attrs["name"]
+        except KeyError:
+            return
+        nodes.append(value)
+    parser.StartElementHandler = start_element
+    parser.Parse(xmlstring)
+    return nodes
+
+class OnoffControl(dbus.service.Object):
+    domain = default_busname
+    path = object_prefix
+
+    def __init__(self, bus, name, device):
+        """
+        @type bus: dbus.Bus
+        @type name: str
+        @type device: OnoffDevice
+        """
+        busname = dbus.service.BusName(self.domain, bus=bus)
+        dbus.service.Object.__init__(self, busname, "%s/%s" % (self.path, name))
+        self.device = device
+        self.usecount = 0
+        device.notify.add(self.changestate)
+
+    @dbus.service.signal(domain, signature="q")
+    def changestate(self, state):
+        logger.debug("emitting state %d", state)
+
+    @dbus.service.method(domain, out_signature="q")
+    def state(self):
+        return self.device.state
+
+    @dbus.service.method(domain, in_signature="q", out_signature="q")
+    def activatetime(self, duration):
+        """Activate the device for a given number of seconds."""
+        logger.info("activatetime %d", duration)
+        GObject.timeout_add(duration * 1000, self.unuse)
+        return self.use()
+
+    @dbus.service.method(domain, in_signature="", out_signature="qh")
+    def activatefd(self):
+        """Activate a device until the returned file descriptor is closed."""
+        logger.info("activatefd")
+        notifyfd, retfd = socketpair()
+        def callback(fd, _):
+            logger.info("fd %d completed", fd.fileno())
+            fd.close()
+            self.unuse()
+            return False
+        GObject.io_add_watch(notifyfd, GObject.IO_HUP|GObject.IO_ERR, callback)
+        return (self.use(), retfd)
+
+    def use(self):
+        self.usecount += 1
+        if self.usecount <= 1:
+            self.device.activate()
+        return self.device.state
+
+    def unuse(self):
+        self.usecount -= 1
+        if not self.usecount:
+            self.device.deactivate()
+        else:
+            logger.debug("%d users left", self.usecount)
+        return False