Work with Multihashes directly

[hsanjuan]

This will be breaking for anyone using filestore who has not migrated
the underlying storage and coverted CIDs to raw multihashes.

It keeps the outside interfaces intact except for ListRes which includes
a multihash rather than a Cid.

[Stebalien]

Other than the nits, my only real concern is that switching everything to multihashes is, strictly speaking, throwing away correct information that we have. We only reference "raw leaves" with the filestore so we always know the codec.

[hsanjuan]

switching everything to multihashes is, strictly speaking, throwing away correct information that we have

We are doing this in general right? IPFS will lose any clue on what type of content it is storing in the datastore, other than that provided by context (in this case knowing that /filestore things are raw). But that was the case with CID v0s anyways..

[Stebalien]

We are doing this in general right? IPFS will lose any clue on what type of content it is storing in the datastore, other than that provided by context (in this case knowing that /filestore things are raw). But that was the case with CID v0s anyways..

Not quite.

• The blockstore stores blocks with different versions/formats. We're intentionally throwing this information away so we don't have to re-download blocks when we're just changing the CID version.
• The filestore only stores CIDv1-raw blocks so we don't have this issue.

[Stebalien]

Now we just need the filestore migration.

[Stebalien]

Comment on where this lives in the migration process (context for anyone wondering):

This change isn't strictly speaking necessary for stage 1 as (a) the blockstore interfaces still use CIDs and (b) all blocks in the filestore will be cidv1 raw blocks. However, when we migrate the blockstore interfaces to multihashes, we'd either have to convert inbound multihashes back into CIDs when looking them up in the filestore's section of the datastore or we'd have to migrate at that point.

Migrating now and using multihashes everywhere is likely the cleanest solution.

[hsanjuan]

Migrating now and using multihashes everywhere is likely the cleanest solution.

I'll add this to the migration

[hsanjuan]

Do not merge: I need to set the right go-ipfs-blockstore dependency here before merging

[hsanjuan]

I have fixed the deps and merged. I tagged v1.0.0 even if this was not breaking and things worked without needing a migration because all filestore blocks are CidV1.Raw. Just in case someone, somewhere, has done something else with this or misused it somehow.