Before this change, buildRustCrate always called rustc with
--extern libName=[...]libName[...]
However, Cargo permits using a different name under which a dependency
is known to a crate. For example, rand 0.7.0 uses:
[dependencies]
getrandom_package = { version = "0.1.1", package = "getrandom", optional = true }
Which introduces the getrandom dependency such that it is known as
getrandom_package to the rand crate. In this case, the correct extern
flag is of the form
--extern getrandom_package=[...]getrandom[...]
which is currently not supported. In order to support such cases, this
change introduces a crateRenames argument to buildRustCrate. This
argument is an attribute set of dependencies that should be renamed. In
this case, crateRenames would be:
{
"getrandom" = "getrandom_package";
}
The extern options are then built such that if the libName occurs as
an attribute in this set, it value will be used as the local
name. Otherwise libName will be used as before.
This commit adds test based on real-world crates (brotli).
There were a few more edge cases that were missing beforehand. Also it
turned out that we can get rid of the `finalBins` list since that will
now be handled during runtime.
Cargo has a few odd (old) ways of picking source files if the `bin.path`
attribute isn't given in the Cargo.toml. This commit adds support for
some of those. The previous behaviour always defaulted to `src/main.rs`
which was not always the right choice.
Since there is look-ahead into the unpacked sources before running the
actual builder the path selection logic has to be embedded within the
build script.
`buildRustCrate` currently supports two ways of running building
binaries when processing a crate:
- Explicit definition of all the binaries (& optionally the paths to
their respective `main.rs`) and,
- if not binary was explictly configured all files matching the patterns
`src/main.rs`, `src/bin/*.rs`.
When the explicit list is given without path information paths are now
being picked from a list of candidates. The first match wins. The order
is the same as within the cargo compatibility code.
If the crate does not provide any libraries the path `src/{bin_name}.rs`
is also considered.
All underscores within the binary names are translated into dashes (`-`)
before the lookups are made. This seems to be a common convention.
