first draft for a simple hooks based custom attribute storage, with a BytesFileSystemStorage POC implementation. Basically: * a dictionary contains maps from which attribute of which entity types are mapped to which custom storage * hooks check for one of these entity type being added/modified/deleted * read is based on the sql generator callback mecanism (used in vcsfile for instance) * all storages have the same basic interface (read, add, update, delete), and should be pluggable in a transparent way (except at migration time when one want to change from a storage to another) * the sample BytesFileSystemStorage: * may store Bytes attributes content of any entity type as file on the file system * is based on one FSPATH rql/sql function and another _fsopen only available in sql * has a dumb file name allocation algorithm

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/* -*- sql -*- 

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   mysql specific registered procedures, 

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*/

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/* XXX limit_size version dealing with format as postgres version does.

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   XXX mysql doesn't support overloading, each function should have a different name

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   NOTE: fulltext renamed since it cause a mysql name conflict

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 */

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CREATE FUNCTION text_limit_size(vfulltext TEXT, maxsize INT)

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RETURNS TEXT

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NO SQL

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BEGIN

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    IF LENGTH(vfulltext) < maxsize THEN

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       RETURN vfulltext;

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    ELSE

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       RETURN SUBSTRING(vfulltext from 1 for maxsize) || '...';

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    END IF;

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END ;;