[feature] Single Asset Vault

[thejohnfreeman]

This PR exists for incremental review. It remade XRPLF#5147. The branch is based on a merge of:

• MPT w/ STIssue wrapping Asset (Add MPTIssue to STIssue XRPLF/rippled#5200)
• STNumber (Add a new serialized type: STNumber XRPLF/rippled#5121)
• levelization, which moved XRPIssue and IOUIssue from the basics module to the protocol module (Enforce levelization in libxrpl with CMake XRPLF/rippled#5111)

Below is how to rebase this work when one of the above branches changes. If one of them is merged into develop, then generally it is best to wait until Greg merges develop into his feature/mpt-stissue branch.

# First, create the vault-base branch.
git fetch gregt feature/mpt-stissue
git fetch jfreeman levels
git checkout -b tmp gregt/feature/mpt-stissue
git merge jfreeman/levels
git checkout vault-base
# Make sure the old state is saved somewhere.
git branch old-vault-base
git reset --hard tmp
git push --force
git branch -D tmp
# Rebase the vault branch. Assumes you have the old vault-base saved in old-vault-base.
# Otherwise, you need to pick through the commit history to find it.
git checkout vault
git rebase --onto vault-base old-vault-base
# Test and then push
cupcake install
.install/bin/rippled --unittest ripple.tx.Vault
git push --force
git branch -D old-vault-base

[Bronek]

please do not use _ as a variable or data member name; C++ is about to get special meaning for it https://wg21.link/P2169

[Bronek]

... already in C++ draft https://eel.is/c++draft/basic.scope.scope#5

[Bronek]

can this be explicit ?

[thejohnfreeman]

It's a function call operator. What is there to make explicit?

[Bronek]

Doh. For some reason I thought this to be conversion. NVM :)

[Bronek]

I guess we do not have flag lsfShareNonTransferable because, for this purpose, we will rely on lsfMPTCanTransfer instead ?

[Bronek]

also need flag lsfFrozen

[thejohnfreeman]

Answer to lsfShareNonTransferable: correct. Please refer to the spec.

Answer to lsfFrozen: there is no vault freeze, thus no lsfFrozen.

[Bronek]

I am confused by the use of STAmount and Number in the above three function signatures. I would assume that when we return take/shares, it would be STAmount (but that's not correct) or when we take/return assets that would be ... Number ?? but that's also not correct.

[thejohnfreeman]

When I first wrote these, they returned Number. They had no callers. Now that I'm calling them, I want STAmount. I've switched the first one now that it has a caller. I expect to switch the others when I write a call for them.

[Bronek]

please add comment what these things are (e.g. hexadecimal blobs equivalent to N many bytes)