[API] introduce reference counting for all modules/objects

[dgollub]

There are still modules/objects without reference-counting. Usually you can identify them since they provide interfaces like osync_XXXX_free().

Task:

1. introduce ref-counter in module/object-struct
2. implement _ref and _unref functions
3. drop osync_xyz_free()

[ianmartin]

Patch to add reference counting to osync_plugin_env

[ianmartin]

Patch to add reference counting to OSyncPluginEnv

[dgollub]

Thanks, patch looks good, testsuite is running...

[dgollub]

Replying to ianmartin:

Patch to add reference counting to OSyncPluginEnv

Committed with r4333 - thanks a lot!

Left candidates:

1. OSyncFormatEnv
2. OSyncGroupEnv
3. OSyncQueue
4. OSyncCapability
5. OSyncModule
6. OSyncThread
7. OSyncXMLFieldList
8. OSyncXMLField

Exclude:

1. OSyncList (to stay in sync with GList)

[ianmartin]

OSyncFormatEnv reference counting added in r4343

This patch introducs two new and removes one public interface(s): -osync_format_env_free +osync_format_env_unref +osync_format_env_ref

[chi70]

patch for vformat

[felixmoeller]

my query just detects the patch in front. See  http://opensync.org/report/12

[ianmartin]

OSyncGroupEnv committed in r4372

OSyncQueue committed in r4373

[ianmartin]

OSyncModule committed in r4374

[dgollub]

All mentioned patches got committed - including the vformat.diff with r4347

[ianmartin]

OSyncThread reference counting adding in r4375

[ianmartin]

Left are:

# OSyncCapability # OSyncXMLFieldList # OSyncXMLField

OSyncCapability is essentially a linked list of OSyncCapability elements. So in the same way as OSyncList does it make sense to have reference counting?

The XMLField elements are used in a very non OO way in xmlformat so this is a more complicated task. Is this a change we want to make?

[dgollub]

Replying to ianmartin:

Left are:

# OSyncCapability # OSyncXMLFieldList # OSyncXMLField

OSyncCapability is essentially a linked list of OSyncCapability elements. So in the same way as OSyncList does it make sense to have reference counting?

No.

The XMLField elements are used in a very non OO way in xmlformat so this is a more complicated task. Is this a change we want to make?

Not quite sure - internally we have still some _free() method for this. Introducing here ref-confing for OSyncXMLField as well would help to keep a clean API design. Since every "object" would have ref-counting.

Reg. OSyncCapability - i need to check if this get used at all. Maybe we can drop this - not quite sure - but is this used in the Public API at all in combination with other interfaces? e.g. OSyncPluginInfo? If not, what about dropping OSyncCapability entirely?

Reg. OSyncXMLFieldList - i need to check if there is any different to OSyncList. Maybe this got changed introduced to "wrap" GList...

[dgollub]

Replying to dgollub:

Replying to ianmartin:

Left are:

# OSyncCapability # OSyncXMLFieldList # OSyncXMLField

OSyncCapability is essentially a linked list of OSyncCapability elements. So in the same way as OSyncList does it make sense to have reference counting?

No.

Just checked - OSyncCapability doesn't get used at all in the Public API. For "attaching" Capabilities to a plugin OSyncCapabilities get used instead. So i would vote for dropping OSyncCapability completely. Thoughts?

[...]

[ianmartin]

Replying to dgollub:

Replying to dgollub:

Replying to ianmartin:

Left are:

# OSyncCapability # OSyncXMLFieldList # OSyncXMLField

OSyncCapability is essentially a linked list of OSyncCapability elements. So in the same way as OSyncList does it make sense to have reference counting?

No.

Just checked - OSyncCapability doesn't get used at all in the Public API. For "attaching" Capabilities to a plugin OSyncCapabilities get used instead. So i would vote for dropping OSyncCapability completely. Thoughts?

Dynamic capability generation in plugins requires the use of osync_capability_new so it cant be dropped.

[ianmartin]

osync_field_free is internal to OSyncField. I dont think reference counting makes sense as a OSyncField only makes sense as part of an OSyncXMLFormat. It cannot be part of two OSyncXMLFormats and if you free the parent OSyncXMLFormat the field would be corrupted if you tried to use it. There can therefore only be one meaningful reference to the field from the parent format.

The only external 'free' function is osync_field_delete which removes the field from the OSyncXMLFormat and frees it.

[dgollub]

So everything expect OSyncXMLField got reference counting. Thanks Ian!