Bug 18055

Summary:	[abi-break] telepathy-glib should use glib-mkenums for enums not exposed on D-Bus
Product:	Telepathy	Reporter:	Murray Cumming <murrayc>
Component:	tp-glib	Assignee:	Telepathy bugs list <telepathy-bugs>
Status:	RESOLVED FIXED	QA Contact:	Telepathy bugs list <telepathy-bugs>
Severity:	normal
Priority:	medium	CC:	danielle
Version:	unspecified
Hardware:	Other
OS:	All
Whiteboard:	ABI-break
i915 platform:		i915 features:
Attachments:	0001-2008-10-14-Murray-Cumming-murrayc-murrayc.com.patch

Description Murray Cumming 2008-10-14 01:48:19 UTC

telepathy-glib should use glib-mkenums to generate tp-enum-types.[h|c], so that it can register correct types for signals and properties.

For instance, that would allow the attached patch to work.

It's difficult to integrate glib-mkenums into a Makefile.am, particularly when you are generating other code already. Pango is probably a good example:
http://svn.gnome.org/viewvc/pango/trunk/pango/Makefile.am?view=markup

Comment 1 Murray Cumming 2008-10-14 01:48:59 UTC

Created attachment 19649 [details] [review]
0001-2008-10-14-Murray-Cumming-murrayc-murrayc.com.patch

Comment 2 Will Thompson 2008-10-24 09:15:19 UTC

In the case you attach a patch for, we can't fix this without breaking ABI; we'll aim to do this right in future when adding new enums not exposed in the D-Bus API, and I'm marking this bug as one we can deal with when we decide to break telepathy-glib's ABI.

In the cases where enums come from the Telepathy D-Bus specification, we can't fix this because dbus-glib expects G_TYPE_UINT for them, rather than some GType corresponding to a GEnum.

Comment 3 Murray Cumming 2009-01-12 08:02:25 UTC

This would also allow us to use g_value_set_enum() instead of g_value_set_int(), as people expect when writing code, for instance when setting a GValue to TP_HANDLE_TYPE_CONTACT.

Comment 4 Murray Cumming 2009-01-12 08:03:41 UTC

(In reply to comment #2)
> In the cases where enums come from the Telepathy D-Bus specification, we can't
> fix this because dbus-glib expects G_TYPE_UINT for them, rather than some GType
> corresponding to a GEnum.

This seems like an error in your code that calls dbus-glib. Surely you can just transform the type where necessary.

Comment 5 Danielle Madeley 2009-09-18 04:16:23 UTC

So I recently asked why the new TpAccount wrapper-API wasn't using GEnums and was pointed to this bug.

It seems to me like we could possibly use GEnum in new API, except for the following problems:
 * API would be inconsistent between old and new APIs
 * GEnum is strict about guarding against values outside the range, this is a problem if the other end is using a newer version of the Telepathy spec.

It's possible that the second problem could be fixed with the addition of a g_value_force_enum(), which would be like set_enum() but without the bounds checking. The idea being that you enforce enum bounds checking on the API side, but you accept any incoming value on the D-Bus side.

I wonder if, even if it's not used in the API, it's worth adding glib-mkenums to the build, so that we can dump the names of specified enum values for debugging with g_enum_get_value().

Comment 6 Simon McVittie 2010-05-10 08:53:27 UTC

I'm going to call this FIXED, since Danielle added enum/flags types for all the hand-written enums.

TpConnectionManager:info-source is still of type UINT since otherwise it'd be an ABI break, but this is now flagged in the documentation.

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