Fix#1020 (see more relevant discussion there)
This definitely makes the amount of generics compiler
has to generate by avoding generating the same functions
for `R`, &mut R`, `&mut &mut R` and so on.
old:
```
> ls -al target/release/deps/bitcoin-07a9dabf1f3e0266
-rwxrwxr-x 1 dpc dpc 9947832 Jun 2 22:42 target/release/deps/bitcoin-07a9dabf1f3e0266
> strip target/release/deps/bitcoin-07a9dabf1f3e0266
> ls -al target/release/deps/bitcoin-07a9dabf1f3e0266
-rwxrwxr-x 1 dpc dpc 4463024 Jun 2 22:46 target/release/deps/bitcoin-07a9dabf1f3e0266
```
new:
```
> ls -al target/release/deps/bitcoin-07a9dabf1f3e0266
-rwxrwxr-x 1 dpc dpc 9866800 Jun 2 22:44 target/release/deps/bitcoin-07a9dabf1f3e0266
> strip target/release/deps/bitcoin-07a9dabf1f3e0266
> ls -al target/release/deps/bitcoin-07a9dabf1f3e0266
-rwxrwxr-x 1 dpc dpc 4393392 Jun 2 22:45 target/release/deps/bitcoin-07a9dabf1f3e0266
```
In the unit-test binary itself, it saves ~100KB of data.
I did not expect much performance gains, but turn out I was wrong(*):
old:
```
test blockdata::block::benches::bench_block_deserialize ... bench: 1,072,710 ns/iter (+/- 21,871)
test blockdata::block::benches::bench_block_serialize ... bench: 191,223 ns/iter (+/- 5,833)
test blockdata::block::benches::bench_block_serialize_logic ... bench: 37,543 ns/iter (+/- 732)
test blockdata::block::benches::bench_stream_reader ... bench: 1,872,455 ns/iter (+/- 149,519)
test blockdata::transaction::benches::bench_transaction_deserialize ... bench: 136 ns/iter (+/- 3)
test blockdata::transaction::benches::bench_transaction_serialize ... bench: 51 ns/iter (+/- 8)
test blockdata::transaction::benches::bench_transaction_serialize_logic ... bench: 5 ns/iter (+/- 0)
test blockdata::transaction::benches::bench_transaction_size ... bench: 3 ns/iter (+/- 0)
```
new:
```
test blockdata::block::benches::bench_block_deserialize ... bench: 1,028,574 ns/iter (+/- 10,910)
test blockdata::block::benches::bench_block_serialize ... bench: 162,143 ns/iter (+/- 3,363)
test blockdata::block::benches::bench_block_serialize_logic ... bench: 30,725 ns/iter (+/- 695)
test blockdata::block::benches::bench_stream_reader ... bench: 1,437,071 ns/iter (+/- 53,694)
test blockdata::transaction::benches::bench_transaction_deserialize ... bench: 92 ns/iter (+/- 2)
test blockdata::transaction::benches::bench_transaction_serialize ... bench: 17 ns/iter (+/- 0)
test blockdata::transaction::benches::bench_transaction_serialize_logic ... bench: 5 ns/iter (+/- 0)
test blockdata::transaction::benches::bench_transaction_size ... bench: 4 ns/iter (+/- 0)
```
(*) - I'm benchmarking on a noisy laptop. Take this with a grain of salt. But I think
at least it doesn't make anything slower.
While doing all this manual labor that will probably generate conflicts,
I took a liberty of changing generic type names and variable names to
`r` and `R` (reader) and `w` and `W` for writer.
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`.
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.
Dawid Ciężarkiewicz
Tobin C. Harding
Ben Carman