[Xapian-tickets] [Xapian] #504: Add is_closed() to Database class

[Xapian]

#504: Add is_closed() to Database class
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 Reporter:  jcassee      |       Owner:  olly
     Type:  enhancement  |      Status:  new 
 Priority:  normal       |   Milestone:      
Component:  Library API  |     Version:      
 Severity:  minor        |    Keywords:      
Blockedby:               |    Platform:  All 
 Blocking:               |  
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Comment(by jcassee):

 I meant 'dire' in a tongue-in-cheek way. I was reacting to the "this may
 happen or that may happen, and you will not know which one" feel of the
 text. I agree with [comment:1 Olly] that the behaviour is consistent and
 necessary for performance reasons. It is something I had to think about,
 though, and I thought "let's just not use the database when it is closed".

 A search function that uses Xapian will be a relatively expensive action,
 and in that case a check whether the database is still open is relatively
 cheap. I was thinking that such function would have to keep a 'database is
 closed' flag if it were interested in that fact. And then I thought, what
 code knows better whether the database is closed than the database itself?
 Why would I not be able to ask the database whether it is closed?

 I may have come on a bit strong in my ticket description, sorry. The lack
 of an `is_closed()` method seemed an oversight, but I had not considered
 that even a small change means an investment of your time and must add
 real value.

 A suggestion to improve the documentation of the `close()` method would be
 to reduce the 'heavyness' of the second half:

 "After this call, calls made to methods of the database will either behave
 exactly as they would have done if the database had not been closed (if
 the method uses cached data) or raise a Xapian::DatabaseError indicating
 that the database is closed."

 Too much information here indicates that the caller must be very cautious,
 which is not the case.

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Ticket URL: <http://trac.xapian.org/ticket/504#comment:3>
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