Bug 11396

Summary:	Hash tables should be freed with g_hash_table_unref()
Product:	dbus	Reporter:	Marco Barisione <marco.barisione>
Component:	GLib	Assignee:	Rob Taylor <rob.taylor>
Status:	RESOLVED FIXED	QA Contact:	John (J5) Palmieri <johnp>
Severity:	normal
Priority:	medium	CC:	walters
Version:	unspecified
Hardware:	All
OS:	All
Whiteboard:
i915 platform:		i915 features:
Attachments:	Depend on glib 2.10 Use g_hash_table_unref() instead of g_hash_table_destroy() in hash_table_simple_free() Change every occurrence of g_hash_table_destroy() to g_hash_table_unref()

Description Marco Barisione 2007-06-27 08:02:48 UTC

GHashTables are freed with g_hash_table_destroy() instead of g_hash_table_unref().

This could be a problem when dbus-glib passes a hash table to the user's code and the user calls g_hash_table_ref() to keep a reference. After dbus-glib has called g_hash_table_destroy() the user will get an emptied hash table.

g_hash_table_unref() is available only since glib 2.10.

Comment 1 Marco Barisione 2007-06-27 08:03:59 UTC

Created attachment 10472 [details] [review]
Depend on glib 2.10

Comment 2 Marco Barisione 2007-06-27 08:09:25 UTC

Created attachment 10473 [details] [review]
Use g_hash_table_unref() instead of g_hash_table_destroy() in hash_table_simple_free()

This change is backward compatible, nothing should happen because now you always need to copy the table so you don't care if dbus is using _destroy or _unref. The only difference would be in the case you are using _ref to get an empty hash table :)

However, this change should be documented so, if you are depending on an older version of dbus-glib, you know that you should dup the hash table.

Comment 3 Marco Barisione 2007-06-27 08:11:01 UTC

Created attachment 10474 [details] [review]
Change every occurrence of g_hash_table_destroy() to g_hash_table_unref()

Other occurrences of g_hash_table_destroy() should not be a problem for users, but maybe it's a good idea to change them too.

Comment 4 Colin Walters 2008-05-27 11:35:18 UTC

I like the non-wholesale version; trying to be conservative with changes.  We can revisit changing to _unref in other places if necessary later.

I also modified the patch to use GLIB_CHECK_VERSION to allow compilation on older glibs.

commit a8bf32ab8b0e30e0c74e07c58e9bc79a448683b2
Author: Colin Walters <walters@verbum.org>
Date:   Tue May 27 14:31:58 2008 -0400

    Bug 11396: Use g_hash_table_unref if available (Marco Barisione)
    
    This lets users ref hashes with g_hash_table_ref.

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