Scaffold utility and library (#3)

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

crates/solc-binaries/src/cache.rs

@@ -0,0 +1,71 @@
+//! Helper for caching the solc binaries.
+
+use std::{
+    collections::HashSet,
+    fs::{File, create_dir_all},
+    io::{BufWriter, Write},
+    os::unix::fs::PermissionsExt,
+    path::{Path, PathBuf},
+    sync::{LazyLock, Mutex},
+};
+
+use crate::download::GHDownloader;
+
+pub const SOLC_CACHE_DIRECTORY: &str = "solc";
+pub(crate) static SOLC_CACHER: LazyLock<Mutex<HashSet<PathBuf>>> = LazyLock::new(Default::default);
+
+pub(crate) fn get_or_download(
+    working_directory: &Path,
+    downloader: &GHDownloader,
+) -> anyhow::Result<PathBuf> {
+    let target_directory = working_directory
+        .join(SOLC_CACHE_DIRECTORY)
+        .join(downloader.version.to_string());
+    let target_file = target_directory.join(downloader.target);
+
+    let mut cache = SOLC_CACHER.lock().unwrap();
+    if cache.contains(&target_file) {
+        log::debug!("using cached solc: {}", target_file.display());
+        return Ok(target_file);
+    }
+
+    create_dir_all(target_directory)?;
+    download_to_file(&target_file, downloader)?;
+    cache.insert(target_file.clone());
+
+    Ok(target_file)
+}
+
+fn download_to_file(path: &Path, downloader: &GHDownloader) -> anyhow::Result<()> {
+    log::info!("caching file: {}", path.display());
+
+    let Ok(file) = File::create_new(path) else {
+        log::debug!("cache file already exists: {}", path.display());
+        return Ok(());
+    };
+
+    #[cfg(unix)]
+    {
+        let mut permissions = file.metadata()?.permissions();
+        permissions.set_mode(permissions.mode() | 0o111);
+        file.set_permissions(permissions)?;
+    }
+
+    let mut file = BufWriter::new(file);
+    file.write_all(&downloader.download()?)?;
+    file.flush()?;
+    drop(file);
+
+    #[cfg(target_os = "macos")]
+    std::process::Command::new("xattr")
+        .arg("-d")
+        .arg("com.apple.quarantine")
+        .arg(&path)
+        .stderr(std::process::Stdio::null())
+        .stdout(std::process::Stdio::null())
+        .stdout(std::process::Stdio::null())
+        .spawn()?
+        .wait()?;
+
+    Ok(())
+}

crates/solc-binaries/src/download.rs

@@ -0,0 +1,146 @@
+//! This module downloads solc binaries.
+
+use std::{
+    collections::HashMap,
+    sync::{LazyLock, Mutex},
+};
+
+use semver::Version;
+use sha2::{Digest, Sha256};
+
+use crate::list::List;
+
+pub static LIST_CACHE: LazyLock<Mutex<HashMap<&'static str, List>>> =
+    LazyLock::new(Default::default);
+
+impl List {
+    pub const LINUX_URL: &str = "https://binaries.soliditylang.org/linux-amd64/list.json";
+    pub const WINDOWS_URL: &str = "https://binaries.soliditylang.org/windows-amd64/list.json";
+    pub const MACOSX_URL: &str = "https://binaries.soliditylang.org/macosx-amd64/list.json";
+    pub const WASM_URL: &str = "https://binaries.soliditylang.org/wasm/list.json";
+
+    /// Try to downloads the list from the given URL.
+    ///
+    /// Caches the list retrieved from the `url` into [LIST_CACHE],
+    /// subsequent calls with the same `url` will return the cached list.
+    pub fn download(url: &'static str) -> anyhow::Result<Self> {
+        if let Some(list) = LIST_CACHE.lock().unwrap().get(url) {
+            return Ok(list.clone());
+        }
+
+        let body: List = reqwest::blocking::get(url)?.json()?;
+
+        LIST_CACHE.lock().unwrap().insert(url, body.clone());
+
+        Ok(body)
+    }
+}
+
+/// Download solc binaries from GitHub releases (IPFS links aren't reliable).
+#[derive(Clone, Debug)]
+pub struct GHDownloader {
+    pub version: Version,
+    pub target: &'static str,
+    pub list: &'static str,
+}
+
+impl GHDownloader {
+    pub const BASE_URL: &str = "https://github.com/ethereum/solidity/releases/download";
+
+    pub const LINUX_NAME: &str = "solc-static-linux";
+    pub const MACOSX_NAME: &str = "solc-macos";
+    pub const WINDOWS_NAME: &str = "solc-windows.exe";
+    pub const WASM_NAME: &str = "soljson.js";
+
+    fn new(version: Version, target: &'static str, list: &'static str) -> Self {
+        Self {
+            version,
+            target,
+            list,
+        }
+    }
+
+    pub fn linux(version: Version) -> Self {
+        Self::new(version, Self::LINUX_NAME, List::LINUX_URL)
+    }
+
+    pub fn macosx(version: Version) -> Self {
+        Self::new(version, Self::MACOSX_NAME, List::MACOSX_URL)
+    }
+
+    pub fn windows(version: Version) -> Self {
+        Self::new(version, Self::WINDOWS_NAME, List::WINDOWS_URL)
+    }
+
+    pub fn wasm(version: Version) -> Self {
+        Self::new(version, Self::WASM_NAME, List::WASM_URL)
+    }
+
+    /// Returns the download link.
+    pub fn url(&self) -> String {
+        format!("{}/v{}/{}", Self::BASE_URL, &self.version, &self.target)
+    }
+
+    /// Download the solc binary.
+    ///
+    /// Errors out if the download fails or the digest of the downloaded file
+    /// mismatches the expected digest from the release [List].
+    pub fn download(&self) -> anyhow::Result<Vec<u8>> {
+        log::info!("downloading solc: {self:?}");
+        let expected_digest = List::download(self.list)?
+            .builds
+            .iter()
+            .find(|build| build.version == self.version)
+            .ok_or_else(|| anyhow::anyhow!("solc v{} not found builds", self.version))
+            .map(|b| b.sha256.strip_prefix("0x").unwrap_or(&b.sha256).to_string())?;
+
+        let file = reqwest::blocking::get(self.url())?.bytes()?.to_vec();
+
+        if hex::encode(Sha256::digest(&file)) != expected_digest {
+            anyhow::bail!("sha256 mismatch for solc version {}", self.version);
+        }
+
+        Ok(file)
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::{download::GHDownloader, list::List};
+
+    #[test]
+    fn try_get_windows() {
+        let version = List::download(List::WINDOWS_URL)
+            .unwrap()
+            .latest_release
+            .into();
+        GHDownloader::windows(version).download().unwrap();
+    }
+
+    #[test]
+    fn try_get_macosx() {
+        let version = List::download(List::MACOSX_URL)
+            .unwrap()
+            .latest_release
+            .into();
+        GHDownloader::macosx(version).download().unwrap();
+    }
+
+    #[test]
+    fn try_get_linux() {
+        let version = List::download(List::LINUX_URL)
+            .unwrap()
+            .latest_release
+            .into();
+        GHDownloader::linux(version).download().unwrap();
+    }
+
+    #[test]
+    fn try_get_wasm() {
+        let version = List::download(List::WASM_URL)
+            .unwrap()
+            .latest_release
+            .into();
+        GHDownloader::wasm(version).download().unwrap();
+    }
+}

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)
+}

crates/solc-binaries/src/list.rs

@@ -0,0 +1,26 @@
+//! Rust type definitions for the solc binary lists.
+
+use std::{collections::HashMap, path::PathBuf};
+
+use semver::Version;
+use serde::Deserialize;
+
+#[derive(Debug, Deserialize, Clone, Eq, PartialEq)]
+pub struct List {
+    pub builds: Vec<Build>,
+    pub releases: HashMap<Version, String>,
+    #[serde(rename = "latestRelease")]
+    pub latest_release: Version,
+}
+
+#[derive(Debug, Deserialize, Clone, Eq, PartialEq)]
+pub struct Build {
+    pub path: PathBuf,
+    pub version: Version,
+    pub build: String,
+    #[serde(rename = "longVersion")]
+    pub long_version: String,
+    pub keccak256: String,
+    pub sha256: String,
+    pub urls: Vec<String>,
+}