Cursors as context managers #99
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This adds methods __enter__ and __exit__ to a cursor, providing it with context manager functionality. Leaving a cursor context will close the cursor. It is important to close cursors in a multi-threaded or multi-process SQLite situation with writers present, as open cursors will keep read locks on the database and timely garbage-collection cannot be counted on.
This adds a simple test of cursors as context managers to the test suite.
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Hi,
I think it would be great if cursors could be used as context managers as well. They acquire a limiting resource: Read locks on the database file. In a multi-threaded or multi-process situation, it is important to not rely on (unreliable) garbage collection to mop up any old, open, unused cursors. In such a case, it is easy to end up with 'OperationalError: database is locked' errors on any process attempting to write.
This adds code to use cursors as context managers, like there is already for connections. Included is a simple test case (passes fine on python 2.7.6) and documentation of these methods.
But as a further suggestion, the docs might become more helpful if they would state this problem more clearly. Currently, the code examples do not deal with this problem and implicitly suggest the assumption that Python's garbage collection is sufficient and so implicitly assume a read-only or a single-threaded use-case of pysqlite.