ltt/branches/poly/doc/developer/hook_prio.txt

   1 Linux Trace Toolkit
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   3 Mathieu Desnoyers 18-05-2004
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   6 Seeing that a very precise hook call ordering is needed when processing events
   7 (especially the order for calling state update hooks and event delivery hooks),
   8 this document defines a new type and interface that permits to merge all kind of
   9 hooks, eventually sorted by the priority associated to them.
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  11 - Type LttvHooks with priorities
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  13 This is a modification to the actual LttvHooks that associates a priority with
  14 each hook. The container for this type would be a garray, just like hook.c, but
  15 a lttv_hooks_prio_sort would be called every time a hook is added to a list. It
  16 would sort the hooks in a hook list by priority : from highest priority (-19) to
  17 lowest (20). The default priority is 0.
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  19 In order to make lttv_hooks_call aware of the different kind of hooks it has to
  20 call, the LttvHooksById will be modified to integrate a new "main" list : a
  21 pointer to a LttvHooks that will be called for any Id.
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  23 A new lttv_hooks_by_id_call that will get the hooks from the main and by_id
  24 lists in the right order will deal with the multiple lists priority problem.
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