From: Mark Wooding <mdw@distorted.org.uk>
Date: Sun, 24 May 2015 18:22:29 +0000 (+0100)
Subject: catacomb/pwsafe.py, pwsafe: Dispatching for multiple backends.
X-Git-Tag: 1.1.0~9
X-Git-Url: https://www.chiark.greenend.org.uk/ucgi/~mdw/git/catacomb-python/commitdiff_plain/6baae40547e9218221e7ce5901e28991cedeb60c?ds=inline;hp=6baae40547e9218221e7ce5901e28991cedeb60c

catacomb/pwsafe.py, pwsafe: Dispatching for multiple backends.

This commit introduces a number of tightly related changes.

  * Have concrete backends declare a `NAME' attribute.  This lets users
    name them, and lets us determine which classes are concrete.

  * Introduce a metaclass which registers concrete StorageClass
    subclasses.

  * Extend the `_open' protocol, so that it can raise the new
    StorageBackendRefusal exception to indicate that some other backend
    should try to open the given file.

  * Introduce a `StorageBackend.open' method which examines all
    registered backends and gives each of them an opportunity to open
    the file in some priority order.

  * Add a new method for looking up backends by name.

  * introduce a new DBCLS parameter to `PW.create', which is the backend
    class to use when creating a new database.

  * Introduce a new option to the `create' command to choose the
    database backend by name.

There's only one backend at the moment, though that will change soon.
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