יובל קוג'מן (Yuval Kogman) > KiokuDB-0.51 > KiokuDB::Linker



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Source   Latest Release: KiokuDB-0.57


KiokuDB::Linker - Relinks live objects from storage entries


    # mostly internal


The linker reconnects entry data, recreating the connected object graph in memory.

The linkage process starts with an ID (or several IDs) to be loaded passed to the get_or_load_objects method.

This ID will first be searched for in the live object set (KiokuDB::LiveObjects). If the object is already live, then it will be returned as is.

If the object is not live, then the corresponding entry is fetched from the backend, and expanded into an actual instance.

Expansion consults the KiokuDB::TypeMap using KiokuDB::TypeMap::Resolver, to find the correct typemap entry (see "COLLAPSING STRATEGIES" in KiokuDB::Collapser and KiokuDB::TypeMap), and that is used for the actual expansion.

Most of the grunt work is delegated by the entries back to the linker using the inflate_data method, which handles circular structures, retrying of tied structures, etc.

Inflated objects are registered with KiokuDB::LiveObjects, and get inserted into the current live object scope (KiokuDB::LiveObjects::Scope). The scope's job is to maintain a reference count of at least 1 for any loaded object, until it is destroyed itself. This ensures that weak references are not destroyed prematurely, but allows their use in order to avoid memory leaks.

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