Re: [Bluez-devel] CUPS plugin discovery bits

[Bastien Nocera <hadess@hadess.net>]

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On Wed, 2007-05-23 at 17:51 +0200, Marcel Holtmann wrote:
> Hi Bastien,
> 
> > Here's a patch against CVS bluez-utils to add discovery to the CUPS
> > backend. With this, it means that most CUPS front-end will be able to
> > list visible printers when adding a new one, be it through the web
> > interface or other front-ends (like Fedora' system-config-printer).
> > 
> > It adds D-Bus and glib as dependencies for the backend (not that it
> > matters that much...).
> 
> it actually does. We provide an eGlib for embedded systems and so when
> compiled with GLib, we only use that function subset.
> 
> And second you use the GLib D-Bus bindings. I am not willing to create
> these dependencies for a "daemon" package.

The dependency is already optional (and if not, I can make it so).

I've looked at what using dbus directly would entail, and I'm not sure
that's a good use of my (or anyone's) time. The code would be much more
complicated than it would need to be, and certainly not any more
readable.

In the worst case, how about moving the cups plugin to another module?

> Actually that is the reason why we wanna go
> for a printing service in the future.

I still haven't heard the benefits, or features that service would have.

Unless you want to pass data from a client, over dbus to this printing
service, which I don't think is a good idea given the potential size of
the data being passed over.

If anyone is involved with that, a draft API would be appreciated.

This latest patch avoids untranslated messages getting to the end-user.

Cheers

-- 
Bastien Nocera <hadess@hadess.net> 

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Index: acinclude.m4
===================================================================
RCS file: /cvsroot/bluez/utils/acinclude.m4,v
retrieving revision 1.107
diff -u -p -r1.107 acinclude.m4
--- acinclude.m4	8 Apr 2007 19:56:52 -0000	1.107
+++ acinclude.m4	24 May 2007 14:54:17 -0000
@@ -78,6 +78,8 @@ AC_DEFUN([AC_PATH_GLIB], [
 	PKG_CHECK_MODULES(GLIB, glib-2.0, glib_found=yes, glib_found=no)
 	AC_SUBST(GLIB_CFLAGS)
 	AC_SUBST(GLIB_LIBS)
+	GLIB_GENMARSHAL=`$PKG_CONFIG --variable=glib_genmarshal glib-2.0`
+	AC_SUBST(GLIB_GENMARSHAL)
 ])
 
 AC_DEFUN([AC_PATH_DBUS], [
Index: cups/Makefile.am
===================================================================
RCS file: /cvsroot/bluez/utils/cups/Makefile.am,v
retrieving revision 1.9
diff -u -p -r1.9 Makefile.am
--- cups/Makefile.am	20 Aug 2006 02:21:03 -0000	1.9
+++ cups/Makefile.am	24 May 2007 14:54:17 -0000
@@ -7,9 +7,19 @@ else
 noinst_PROGRAMS = bluetooth
 endif
 
-bluetooth_SOURCES = main.c sdp.c spp.c hcrp.c
-bluetooth_LDADD = @BLUEZ_LIBS@
+MARSHAL_FILES = bluez-cups-marshal.h bluez-cups-marshal.c
 
-AM_CFLAGS = @BLUEZ_CFLAGS@
+bluetooth_SOURCES = main.c sdp.c spp.c hcrp.c $(MARSHAL_FILES)
+bluetooth_LDADD = @DBUS_GLIB_LIBS@ @BLUEZ_LIBS@
 
-MAINTAINERCLEANFILES = Makefile.in
+bluez-cups-marshal.h: bluez-cups-marshal.list
+	$(GLIB_GENMARSHAL) --prefix=bluez_cups_marshal $< --header > $@
+bluez-cups-marshal.c: bluez-cups-marshal.list
+	$(GLIB_GENMARSHAL) --prefix=bluez_cups_marshal $< --body > $@
+main.c: $(MARSHAL_FILES)
+
+AM_CFLAGS = @BLUEZ_CFLAGS@ @DBUS_GLIB_CFLAGS@
+
+MAINTAINERCLEANFILES = Makefile.in $(MARSHAL_FILES)
+CLEANFILES = $(MARSHAL_FILES)
+EXTRA_DIST = bluez-cups-marshal.list
Index: cups/main.c
===================================================================
RCS file: /cvsroot/bluez/utils/cups/main.c,v
retrieving revision 1.6
diff -u -p -r1.6 main.c
--- cups/main.c	3 Jan 2006 13:28:57 -0000	1.6
+++ cups/main.c	24 May 2007 14:54:17 -0000
@@ -38,12 +38,313 @@
 #include <bluetooth/sdp.h>
 #include <bluetooth/sdp_lib.h>
 
+#include <dbus/dbus-glib.h>
+#include "bluez-cups-marshal.h"
+
 extern int sdp_search_spp(sdp_session_t *sdp, uint8_t *channel);
 extern int sdp_search_hcrp(sdp_session_t *sdp, unsigned short *ctrl_psm, unsigned short *data_psm);
 
 extern int spp_print(bdaddr_t *src, bdaddr_t *dst, uint8_t channel, int fd, int copies);
 extern int hcrp_print(bdaddr_t *src, bdaddr_t *dst, unsigned short ctrl_psm, unsigned short data_psm, int fd, int copies);
 
+#define PRINTER_SERVICE_CLASS_NAME "printer"
+
+typedef struct {
+	char *bdaddr;
+	char *name;
+} BluezCupsDevice;
+
+static GList *device_list = NULL;
+static GMainLoop *loop = NULL;
+
+static void
+add_device_to_list(const char *name, const char *bdaddr)
+{
+	BluezCupsDevice *device;
+	GList *l;
+
+	/* Look for the device in the list */
+	for (l = device_list; l != NULL; l = l->next) {
+		device = (BluezCupsDevice *) l->data;
+
+		if (strcmp(device->bdaddr, bdaddr) == 0) {
+			g_free(device->name);
+			device->name = g_strdup(name);
+			return;
+		}
+	}
+
+	/* Or add it to the list if it's not there */
+	device = g_new0(BluezCupsDevice, 1);
+	device->bdaddr = g_strdup(bdaddr);
+	device->name = g_strdup(name);
+
+	device_list = g_list_prepend(device_list, device);
+}
+
+static void
+print_printer_details(const char *name, const char *bdaddr)
+{
+	char *uri, *escaped;
+
+	escaped = g_strdelimit(g_strdup(name), "\"", '\'');
+	uri = g_strdup_printf("bluetooth://%c%c%c%c%c%c%c%c%c%c%c%c",
+			       bdaddr[0], bdaddr[1],
+			       bdaddr[3], bdaddr[4],
+			       bdaddr[6], bdaddr[7],
+			       bdaddr[9], bdaddr[10],
+			       bdaddr[12], bdaddr[13],
+			       bdaddr[15], bdaddr[16]);
+	g_print("network %s \"Unknown\" \"%s (Bluetooth)\"\n", uri, escaped);
+	g_free(escaped);
+}
+
+static gboolean
+device_is_printer(DBusGProxy *object, const char *bdaddr)
+{
+	GError *e = NULL;
+	char *class;
+
+	dbus_g_proxy_call(object, "GetRemoteMinorClass", &e,
+			   G_TYPE_STRING, bdaddr, G_TYPE_INVALID,
+			   G_TYPE_STRING, &class, G_TYPE_INVALID);
+
+	if (e == NULL && g_str_equal(class, PRINTER_SERVICE_CLASS_NAME)) {
+		return TRUE;
+	} else if(e != NULL) {
+		g_error_free(e);
+	}
+
+	return FALSE;
+}
+
+static void
+add_devices_to_list(DBusGProxy *object, const char **array)
+{
+	GError *e = NULL;
+	while (*array) {
+		const char *name;
+
+		if (!device_is_printer(object, *array)) {
+			array++;
+			continue;
+		}
+		dbus_g_proxy_call (object, "GetRemoteName", &e,
+				   G_TYPE_STRING, *array, G_TYPE_INVALID,
+				   G_TYPE_STRING, &name, G_TYPE_INVALID);
+		if (e == NULL) {
+			add_device_to_list (name, *array);
+		} else {
+			g_error_free (e);
+			e = NULL;
+		}
+		array++;
+	}
+}
+
+static void
+remote_device_found(DBusGProxy *object,
+		     const char *bdaddr, guint class, int rssi,
+		     gpointer user_data)
+{
+	GError *e = NULL;
+	const char *name;
+
+	/* Don't add non-printer devices */
+	if (!device_is_printer(object, bdaddr))
+		return;
+
+	dbus_g_proxy_call(object, "GetRemoteName", &e,
+			   G_TYPE_STRING, bdaddr, G_TYPE_INVALID,
+			   G_TYPE_STRING, &name, G_TYPE_INVALID);
+
+	if(e != NULL) {
+		const char *name;
+
+		name = dbus_g_error_get_name(e);
+		if (g_str_equal(name, "org.bluez.Error.RequestDeferred") != FALSE) {
+			add_device_to_list(NULL, bdaddr);
+		}
+		g_error_free(e);
+	} else {
+		add_device_to_list(name, bdaddr);
+	}
+}
+
+static void
+remote_name_updated(DBusGProxy *object,
+		     const char *bdaddr, const char *name,
+		     gpointer user_data)
+{
+	add_device_to_list(name, bdaddr);
+}
+
+static void
+discovery_completed(DBusGProxy *object, gpointer user_data)
+{
+	GList *l;
+
+	for (l = device_list; l != NULL; l = l->next) {
+		BluezCupsDevice *device = (BluezCupsDevice *) l->data;
+
+		if (device->name == NULL) {
+			device->name = g_strdelimit(g_strdup(device->bdaddr),
+						    ":", '-');
+		}
+		print_printer_details(device->name, device->bdaddr);
+		g_free(device->name);
+		g_free(device->bdaddr);
+		g_free(device);
+	}
+
+	g_list_free(device_list);
+	device_list = NULL;
+
+	g_main_loop_quit(loop);
+}
+
+static void
+remote_device_disappeared(DBusGProxy *object,
+			   const char *bdaddr,
+			   gpointer user_data)
+{
+	GList *l;
+
+	for (l = device_list; l != NULL; l = l->next) {
+		BluezCupsDevice *device = (BluezCupsDevice *) l->data;
+
+		if (strcmp(device->bdaddr, bdaddr) == 0) {
+			g_free(device->name);
+			g_free(device->bdaddr);
+			g_free(device);
+			device_list = g_list_delete_link(device_list, l);
+			return;
+		}
+	}
+}
+
+static gboolean
+list_known_printers(DBusGProxy *object)
+{
+	GError *e = NULL;
+	const char **array;
+
+	dbus_g_proxy_call (object, "ListRemoteDevices", &e,
+			   G_TYPE_INVALID, G_TYPE_STRV, &array, G_TYPE_INVALID);
+	if (e == NULL) {
+		add_devices_to_list (object, array);
+	} else {
+		/* Most likely bluez-utils < 3.8, so no ListRemoteDevices */
+		const char *name;
+
+		name = dbus_g_error_get_name (e);
+		if (g_str_equal (name, "org.bluez.Error.UnknownMethod") != FALSE) {
+			g_error_free (e);
+			e = NULL;
+			dbus_g_proxy_call (object, "ListBondings", &e,
+					   G_TYPE_INVALID, G_TYPE_STRV, &array, G_TYPE_INVALID);
+			if (e == NULL) {
+				add_devices_to_list (object, array);
+			} else {
+				g_error_free (e);
+			}
+		} else {
+			g_error_free (e);
+		}
+	}
+
+	return FALSE;
+}
+
+static void
+list_printers(void)
+{
+	/* 1. Connect to the bus
+	 * 2. Get the manager
+	 * 3. Get the default adapter
+	 * 4. Get a list of devices
+	 * 5. Get the class of each device
+	 * 6. Print the details from each printer device
+	 */
+	GError *e = NULL;
+	DBusGConnection *conn;
+	DBusGProxy *object;
+	const char *adapter;
+
+	g_type_init();
+
+	conn = dbus_g_bus_get(DBUS_BUS_SYSTEM, &e);
+	if (e != NULL) {
+		g_warning("Couldn't connect to bus: %s", e->message);
+		g_error_free(e);
+		return;
+	}
+
+	object = dbus_g_proxy_new_for_name(conn, "org.bluez",
+					    "/org/bluez", "org.bluez.Manager");
+	dbus_g_proxy_call(object, "DefaultAdapter", &e,
+			   G_TYPE_INVALID, G_TYPE_STRING, &adapter, G_TYPE_INVALID);
+	if (e != NULL) {
+		const char *name;
+
+		name = dbus_g_error_get_name(e);
+
+		/* No adapter */
+		if (g_str_equal(name, "org.bluez.Error.NoSuchAdapter") != FALSE) {
+			g_error_free(e);
+			return;
+		}
+
+		g_warning("Couldn't get default bluetooth adapter: %s",
+			   e->message);
+		g_error_free(e);
+		return;
+	}
+
+	object = dbus_g_proxy_new_for_name(conn, "org.bluez",
+					    adapter, "org.bluez.Adapter");
+
+	dbus_g_object_register_marshaller(bluez_cups_marshal_VOID__STRING_UINT_INT,
+					  G_TYPE_NONE, G_TYPE_STRING, G_TYPE_UINT,
+					  G_TYPE_INT, G_TYPE_INVALID);
+	dbus_g_proxy_add_signal(object, "RemoteDeviceFound",
+				 G_TYPE_STRING, G_TYPE_UINT, G_TYPE_INT, G_TYPE_INVALID);
+	dbus_g_proxy_connect_signal(object, "RemoteDeviceFound",
+				     G_CALLBACK(remote_device_found), NULL, NULL);
+
+	dbus_g_object_register_marshaller(bluez_cups_marshal_VOID__STRING_STRING,
+					  G_TYPE_NONE, G_TYPE_STRING,
+					  G_TYPE_STRING, G_TYPE_INVALID);
+	dbus_g_proxy_add_signal(object, "RemoteNameUpdated",
+				 G_TYPE_STRING, G_TYPE_STRING, G_TYPE_INVALID);
+	dbus_g_proxy_connect_signal(object, "RemoteNameUpdated",
+				     G_CALLBACK(remote_name_updated), NULL, NULL);
+
+	dbus_g_proxy_add_signal(object, "RemoteDeviceDisappeared",
+				 G_TYPE_STRING, G_TYPE_INVALID);
+	dbus_g_proxy_connect_signal(object, "RemoteDeviceDisappeared",
+				     G_CALLBACK(remote_device_disappeared), NULL, NULL);
+
+	dbus_g_proxy_add_signal(object, "DiscoveryCompleted", G_TYPE_INVALID);
+	dbus_g_proxy_connect_signal(object, "DiscoveryCompleted",
+				     G_CALLBACK(discovery_completed), NULL, NULL);
+
+	dbus_g_proxy_call(object, "DiscoverDevicesWithoutNameResolving", &e,
+			   G_TYPE_INVALID, G_TYPE_INVALID);
+	if (e != NULL) {
+		g_warning("Couldn't start discovery: %s: %s",
+			   dbus_g_error_get_name(e), e->message);
+		g_error_free(e);
+		return;
+	}
+
+	/* Also add the the recent devices */
+	g_idle_add ((GSourceFunc) list_known_printers, object);
+
+	loop = g_main_loop_new(NULL, TRUE);
+	g_main_loop_run(loop);
+}
+
 /*
  *  Usage: printer-uri job-id user title copies options [file]
  *
@@ -73,7 +374,7 @@ int main(int argc, char *argv[])
 #endif /* HAVE_SIGSET */
 
 	if (argc == 1) {
-		puts("network bluetooth \"Unknown\" \"Bluetooth printer\"");
+		list_printers();
 		return 0;
 	}
 
--- /dev/null	2007-05-24 12:42:54.675807888 +0100
+++ cups/bluez-cups-marshal.list	2007-05-23 11:51:07.000000000 +0100
@@ -0,0 +1,2 @@
+VOID:STRING,UINT,INT
+VOID:STRING,STRING

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