Emit clear when a range of blocks is cleared from local storage - #849
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gmaclennan wants to merge 1 commit into
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Emit clear when a range of blocks is cleared from local storage#849gmaclennan wants to merge 1 commit into
clear when a range of blocks is cleared from local storage#849gmaclennan wants to merge 1 commit into
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append and truncate emit session events, but core.clear() emits nothing, so there is no way to observe blocks being removed from local storage (e.g. to re-announce state derived from the local bitfield) without wrapping core.clear. Emit a clear event with the cleared range after the state has been flushed, mirroring the truncate event.
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appendandtruncateemit session events, butcore.clear()emits nothing, so there is no way to observe blocks being removed from local storage. Applications that derive state from the local bitfield (e.g. announcing what they have to other peers over a side channel) need to know when that state shrinks as well as when it grows.This PR emits a
clearevent with the cleared range(start, end)after the clear has been flushed, mirroring thetruncateevent. It is emitted only from the default session state, so atomic batches and named sessions do not emit until their changes land.No behavior change; observability only.
Use case: CoMapeo peers broadcast their "haves" to each other on first connection, before replicating cores. We need to re-broadcast these haves after a clear.
(start, end)matchesclear(start, end)'s arguments. If preferred, we could followtruncate's style, which could carry a richer payload, but the range is what the one known consumer needs.