Update to use new Builder interface for creating CIDs.

[kevina]

No description provided.

[kevina]

This is separated into two commits. The first does the minimal amount of change to support the fact that a Merkeldag has a cid.Builder and not a cid.Prefix. The second renames methods and such so the name is consistent. If the second is too much I can drop it.

[Stebalien]

LGTM but @schomatis may have opinions.

@schomatis for context, this patch allows us to pass around more complex cid "builders" instead of cid prefixes.

The key insight here is that cid.Prefix is informational, it tells you about an existing CID. However, we tend to use it as a "config" or CID builder. This patch replaces those uses with an actual CID builder (introduced here: ipfs/go-cid#53).

[schomatis]

(@Stebalien Thanks for including me and for the context.) This is a great change! I agree that the old Prefix structure was being overextended.

@kevina I'm trying to build this PR but I'm having trouble finding QmWjvVuzD3Dqf3VznGAXUs1VqpG4dd35ounVCnLam8v7Xt (go-ipfs-posinfo), could you help me?

[kevina]

@schomatis Fixed. Forgot to pin that.

[schomatis]

Thanks @kevina, this LGTM but I can't build against go-ipfs because of multiple errors, not related to the PR itself but to the current package management system, so I'm approving this.

(For background, go-cid is imported under the old and new versions, see gx deps dupes, which is more than understandable because it's one of the core packages in the IPFS stack, and gx-go rewrite when building the map ends up -by pure chance- pointing to the old version -that has overwritten the new version previously recorded on the map- and the result is that go-unixfs uses a dependency different from the one it declared in package.json. I have more to say about this but I'll discuss it in more appropriate issues, we need to fix this workflow or I fear that this is going to start blocking contributions.)

[kevina]

@schomatis thanks, I am not 100% following you, but I mostly agree. The way to get around this is to use gx-go link.

In any case this is an API change so to build so it won't build anyway. I will update ipfs/kubo#5281 and id necessary split the automatic inline part into a separate P.R. to avoid blocking anything.