• Philip Withnall's avatar
    core: Support lazy initialisation of properties · 4a59af5c
    Philip Withnall authored
    Creating several HashSets and HashMultiMaps for every Individual turns
    out to be quite wasteful, especially when most of them will typically be
    empty (as address books are generally quite sparse on properties) and never
    accessed (since most clients don’t need local IDs or web service addresses).
    
    This commit delays initialisation of various multi-valued Individual
    properties to the first time they’re accessed, giving them a null value
    before that time. It preserves the existing API for Individual, i.e. the
    properties themselves remain non-nullable, and only the object members
    backing them become nullable.
    
    This does introduce a slight behaviour change, in that an Individual will
    now emit change notifications for a non-initialised multi-valued property if
    *any* of the Personas in the Individual emit a notification for that
    property. This is because the Individual can’t compare the current value of
    its property to the new one resulting from the change in the Persona’s
    property value to determine if a change has really occurred. Therefore the
    Individual makes a safe over-estimate and emits notifications which might
    be false positives.
    
    This shouldn’t be a problem: if a client is interested in the property,
    they will have already queried it and caused it to be initialised.
    Initialised properties have the same notification behaviour as before.
    If a client isn’t interested in the property, it won’t be connected to the
    property notifications anyway.
    
    This change roughly quarters the number of GObjects being created when
    opening folks-inspect with the Telepathy, key-file and EDS backends enabled
    and ~115 personas in the system.
    4a59af5c
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