Scaffold utility and library (#3)

Signed-off-by: Cyrill Leutwiler <bigcyrill@hotmail.com>
Signed-off-by: xermicus <bigcyrill@hotmail.com>

crates/solc-binaries/src/lib.rs

@@ -0,0 +1,39 @@
+//! This crates provides serializable Rust type definitions for the [solc binary lists][0]
+//! and download helpers.
+//!
+//! [0]: https://binaries.soliditylang.org
+
+use std::path::{Path, PathBuf};
+
+use cache::get_or_download;
+use download::GHDownloader;
+use semver::Version;
+
+pub mod cache;
+pub mod download;
+pub mod list;
+
+/// Downloads the solc binary for Wasm is `wasm` is set, otherwise for
+/// the target platform.
+///
+/// Subsequent calls for the same version will use a cached artifact
+/// and not download it again.
+pub fn download_solc(
+    cache_directory: &Path,
+    version: Version,
+    wasm: bool,
+) -> anyhow::Result<PathBuf> {
+    let downloader = if wasm {
+        GHDownloader::wasm(version)
+    } else if cfg!(target_os = "linux") {
+        GHDownloader::linux(version)
+    } else if cfg!(target_os = "macos") {
+        GHDownloader::macosx(version)
+    } else if cfg!(target_os = "windows") {
+        GHDownloader::windows(version)
+    } else {
+        unimplemented!()
+    };
+
+    get_or_download(cache_directory, &downloader)
+}