A `is_spent` field is added to LocalUtxo; when a txo is spent we set
this field to true instead of deleting the entire utxo from the
database.
This allows us to create txs double-spending txs already in blockchain.
Listunspent won't return spent utxos, effectively excluding them from the
coin selection and balance calculation
Although somewhat convenient to have, coupling the Wallet with
the blockchain trait causes development friction and complexity.
What if sometimes the wallet is "offline" (no access to the blockchain)
but sometimes its online?
The only thing the Wallet needs the blockchain for is to sync.
But not all applications will even use the sync method and the sync
method doesn't require the full blockchain functionality.
So we instead pass the blockchain in when we want to sync.
- To further reduce the coupling with blockchain I removed the get_height call from `new` and just use the height of the
last sync in the database.
- I split up the blockchain trait a bit into subtraits.
Verify the unconfirmed transactions we download against the consensus
rules. This is currently exposed as an extra `verify` feature, since it
depends on a pre-release version of `bitcoinconsensus`.
Closes#352
Currently we use `F: f` for the argument that is the default function
passed to `map_or_else` and pass a closure for the second argument. This
bent my brain while reading the documentation because the docs use
`default: D` for the first and `f: F` for the second. Although this is
totally trivial it makes deciphering the combinator chain easier if we
name the arguments the same way the Rust docs do.
Use `default: D` for the identifier of the default function passed into `map_or_else`.
Remove the TODO; refactor matching to correctly handle conditionally
built `Sled` variants. Use `unreachable` instead of `unimplemented` with
a comment hinting that this is a bug, this makes it explicit, both at
runtime and when reading the code, that this match arm should not be hit.
A `[cfg(test)]` function is not as helpful as a macro since it can't be
called in the context of a doctest.
Also adds doctest_wallet macro which can be used to create a wallet in a
doctest.
Change the return type of the `descriptor!()` macro and `ToWalletDescriptor` to
avoid having to map errors.
Also introduce more checks to validate descriptors built using the macro.
