Option to keep a node(sub)queues content unique

Great patch.

It seems that the nodequeue-module has several ways of adding nodes to a queue. We have to handle when people call the nodequeue_save_subqueue_order-function, as it manually clears queue and adds entries, in database. I have attached a revised patch.

I have used this patch and tested the case of adding nodes from the ui. the patch works fine.

Resubmit for testing.

Should apply to HEAD now.

Any ideas why this error is showing up in the tests?

exception: [Notice] Line 1009 of sites/all/modules/nodequeue/nodequeue.module:
Undefined property: stdClass::$unique_entries

I also had a similar use case for implementing uniqueness in the queue. My patch also has a similar approach by having the 'unique_items' field but with much less code to evaluate uniqueness as I used the already available nodequeue_get_subqueue_position() to check if an item is available in the queue instead of a DB query. Also nodequeue_subqueue_add() will only be called only when the uniqueness check is passed.

I get this error when trying to apply the patch in #25 or #24

error: patch failed: nodequeue.module:582
error: nodequeue.module: patch does not apply
error: tests/nodequeue.test: No such file or directory

@danquah Thanks, this works for me now and passes the tests.

It would be great to write a test for this new feature. If anyone has time to write a test, that would be great. Otherwise, I might commit this as-is.

applied patch in #25, its works fine...
attached screenshot

Merged into 7.x-2.x