When `rust-bitcoin` was started in 2014 the SPDX license list and short
identifiers where not a thing. Now that we have short identifiers and
they are gaining popularity in other projects we can consider using
them.
- Add links to the SPDX website in the readme
- Shorten the author section to a single line
- Remove all the licence information in each file and replace it with an
SPDX ID (see https://spdx.dev/ids/#how)
Of note:
- If the author of a file is explicitly listed, maintain this
information
- If the 'author' is listed as the generic 'Rust Bitcoin developers'
just remove the attribution, this is implicit. This does loose the date
info but that can be seen at any time from the git index using
`git log --follow --format=%ad --date default <FILE> | tail -1`
Use cargo to upgrade from edition 2015 to edition 2018.
cargo fix --edition
No manual changes made. The result of the command above is just to fix
all the use statements (add `crate::`) and fix the fully qualified path
formats i.e., `::Foo` -> `crate::Foo`.
Rust idiomatic style is to put the rustdoc _above_ any attributes on
types, functions, etc.
Audit the codebase and move comments/attributes to the correct place.
Add a trailing full stop at times to neaten things up a little extra.
Docs can always do with a bit of love.
Clean up the module level (`//!`) rustdocs for all public modules.
I claim uniform is better than any specific method/style. I tried to fit
in with what ever was either most sane of most prevalent, therefore
attaining uniformity without unnecessary code churn (one exception being
the changes to headings described below).
Notes:
* Headings - use heading as a regular sentence for all modules e.g.,
```
//! Bitcoin network messages.
```
as opposed to
```
//! # Bitcoin Network Messages
```
It was not clear which style to use so I picked a 'random' mature
project and copied their style.
* Added 'This module' in _most_ places as the start of the module
description, however I was not religious about this one.
* Fixed line length if necessary since most of our code seems to follow
short (80 char) line lengths for comments anyways.
* Added periods and fixed obvious (and sometimes not so obvious)
grammatically errors.
* Added a trailing `//!` to every block since this was almost universal
already. I don't really like this one but I'm guessing it is Andrew's
preferred style since its on the copyright notices as well.
`cloudhead` on IRC was asking how to properly use
`BlockHeader::validate_pow()` on genesis (or similar) when the
pow_limit field isn't expressible as a compact target (and, thus,
does not actually represent the PoW limit/genesis target). We
swap it for the actual PoW limit by truncating the way a compact
encoding round-trip would.
Note that, in Bitcoin Core, the original value is only ever used
once in its original form:
```
if (bnNew > bnPowLimit) // Note: bnPowLimit is params.powLimit
bnNew = bnPowLimit;
return bnNew.GetCompact();
```
Thus, even if Core adopted our change, as long as there exist no
256-bit integer x which satisfies
`x <= powLimit && x > encoding_roundtrip_truncated(powLimit)` and
`enoding_roundtrip_truncated(x) != powLimit`, the change would have
no impact on consensus.
It is trivial to show that there are no values which are between
the new value
(0x00000000ffff0000000000000000000000000000000000000000000000000000)
and the original value
(0x00000000ffffffffffffffffffffffffffffffffffffffffffffffffffffffff)
which can be encoded in compact form, but it is also critically, no
such values will encode to a compact form of anything different than
the new value as the encoding always truncates the low bits, never
rounding up.
Tobin C. Harding
Karl-Johan Alm
Matt Corallo
Carl Dong
Dimitris Apostolou