refactor!(stump): Move updated data to its own function #81
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Before this change, `modify` would return the data needed to update a proof for the new block. This requires additional internal computation and extra allocations. During IBD we may never use this, since proof update is only meant for updating a few blocks worth of changes. Now there's a method specific to pull the modify_data, and `modify` itself will only return a new Stump. When refactoring the addition function, I've modified it a little to allow a smarter one with a very nice property: it can pretend that it added a node, but actually represent it as deleted. The goal here is to do a Swift Sync-style protocol where you don't need deletions. If a txout is already spent, you give an empty hash (BitcoinNodeHash::empty()). This will be exactly equivalent as giving this txo's hash and later on calling delete for with this txo's hash. However, it does this with only one call to modify and doesn't require proofs to achieve that. This is an API breaking change, as modify now only returns one parameter, otherwise the behavior stays unchanged.
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| /// and txos to be removed, along with it's proof. Either may be | ||
| /// empty. | ||
| /// | ||
| /// ## Adding stoxs to the stump |
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No. Spent transaction outputs
| /// assert!(s.roots.contains(&utxos[0])); | ||
| /// assert!(!s.roots.contains(&utxos[1])); // The empty hash won't be in the roots |
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So if i got this correctly, you can pass a BitcoinNodeHash::empty() to tell the stump that this UTXO is spent in the future, making the acc not even adding it as a leave right ?
If im correct i would prefer to assert that the num leaves keeps being 1 and the roots num are 1.
correct me if im mistaken but, the roots in that case, if the acc included the other spent UTXO, would never be the spent UTXO, so the check
/// assert!(!s.roots.contains(&utxos[1])); // The empty hash won't be in the roots
doesnt make sense ?
That feature is already proven when you assert that the first utxo became the root right ?
| Ok(new_stump) | ||
| } | ||
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| /// Utreexo is a dynamic accumulator, meaning that leaves can be added and removed. |
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This documentation is good but WYT about a short description on what get_updated_data does before ?
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Before this change,
modifywould return the data needed to update a proof for the new block. This requires additional internal computation and extra allocations. During IBD we may never use this, since proof update is only meant for updating a few blocks worth of changes. Now there's a method specific to pull the modify_data, andmodifyitself will only return a new Stump.When refactoring the addition function, I've modified it a little to allow a smarter one with a very nice property: it can pretend that it added a node, but actually represent it as deleted. The goal here is to do a Swift Sync-style protocol where you don't need deletions.
If a txout is already spent, you give an empty hash (BitcoinNodeHash::empty()). This will be exactly equivalent as giving this txo's hash and later on calling delete for with this txo's hash. However, it does this with only one call to modify and doesn't require proofs to achieve that.
This is an API breaking change, as modify now only returns one parameter, otherwise the behavior stays unchanged.