Addresses #96.
Turns out it was being used for hex encoding/decoding, so replaced that with the `hex` crate.
i chose to import the `decode` method as:
```
use hex::decode as hex_decode
```
so that it is clear to the reader what is being decoded when it is called. "decode" is such a generic sounding function name that it would get confusing otherwise.
This code was unmaintained, is unlikely to work on the majority of systems
(since it holds the whole utxoset in RAM, and not in a terribly efficient
manner), and has a dependency on `eventual` which has been broken for a
long time.
The library no longer compiles on nightly because of this, and without any
known usecases for `UtxoSet`, nor good ability to test it, I'm simply
removing the code.
I recommend anyone who cares about this extracts the code from the previous
commit and creates a new crate. It should be more featureful anyway, e.g.
support a backing store.
Work is stalled on some other library work (to give better lifetime
requirements on `eventual::Future` and avoid some unsafety), so
committing here.
There are only three errors left in this round :)
Also all the indenting is done, so there should be no more massive
rewrite commits. Depending how invasive the lifetime-error fixes
are, I may even be able to do sanely sized commits from here on.
BTW after all this is done I'm gonna indent the entire codebase...
so `git blame` is gonna be totally broken anyway, hence my
capricious cadence of commits.
Now unspendable outs are determined by attempting to create a minimal
satisfying input script. If this can't be done, the output is unspendable.
(Unfortunately this "minimal satisfying script" is not (yet) something
that can be shown to the user, since it is more a bundle of constraints
than actual data pushes.)
Current limitations:
- OP_ADD and friends mean the checker gives the script a free pass.
There is no fundamental reason for this, I just didn't get to it
yet.
- Pubkeys are checked for DER encoding but signatures aren't. This
is because secp256k1 exposes a method for pubkeys, but not one
for sigs :). Signatures are loosely length checked.
Sorry for so many things in one commit ... it was an iterative
process depending as I worked on BIP32 to get the other stuff
working. (And I was too lazy to separate it out after the fact.)
A breaking change by the array newtyping is that Show for Sha256dHash
now outputs the slice Show. You have to use `{:x}` to get the old hex
output.
We get a speed up (~5%) and memory savings (~10%) on initial sync from
using a HashMap, though it's hard to tell precisely how much savings
because it's quite nonlinear.
I haven't tested de/serialization. Some work needs to be done there to
split up the UTXO set since it takes forever to saveload.
Savil Srivastava
Andrew Poelstra
Tamas Blummer
Demur Rumed