OXYGENHUB
◆ v0.3.0 oxygenhub / crates / hub / src / repos / archive.rs
4.0 KiB · Rust · last changed Milestone 0.6: releases, Git mirror, code search, anchored API comments 1 month ago source blame history raw
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//! Source archives of a state (hub spec §9): `.tar.zst` and `.zip` of the
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//! materialised tree, cached by state hash since a state never changes.
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use super::cache::Loaded;
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use oxy_core::objects::NodeKind;
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use oxy_core::repo::Repo;
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use oxy_core::state::FileContent;
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use std::io::Write;
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use std::path::{Path, PathBuf};
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#[derive(Clone, Copy, Debug, PartialEq, Eq)]
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pub enum Format {
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    TarZst,
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    Zip,
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}
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impl Format {
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    pub fn parse(ext: &str) -> Option<Format> {
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        match ext {
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            "tar.zst" => Some(Format::TarZst),
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            "zip" => Some(Format::Zip),
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            _ => None,
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        }
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    }
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    pub fn ext(self) -> &'static str {
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        match self {
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            Format::TarZst => "tar.zst",
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            Format::Zip => "zip",
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        }
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    }
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    pub fn mime(self) -> &'static str {
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        match self {
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            Format::TarZst => "application/zstd",
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            Format::Zip => "application/zip",
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        }
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    }
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}
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/// One archive member: path, bytes, executable, symlink.
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type Member = (String, Vec<u8>, bool, bool);
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/// Every regular file and symlink of the state.
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fn entries(repo: &Repo, loaded: &Loaded) -> anyhow::Result<Vec<Member>> {
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    let mut out = Vec::new();
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    for (path, f) in &loaded.snapshot.files {
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        let bytes = match (&f.kind, &f.content) {
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            (NodeKind::Dir, _) | (_, FileContent::Dir) => continue,
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            (_, FileContent::Text { bytes, .. }) => bytes.clone(),
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            (_, FileContent::Opaque { blobs }) => match blobs.first() {
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                Some(b) => repo.read_blob(b)?,
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                None => vec![],
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            },
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        };
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        out.push((path.clone(), bytes, f.mode.exec, f.kind == NodeKind::Symlink));
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    }
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    Ok(out)
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}
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/// Write the archive of `loaded` under `prefix/` to `dest` (atomically).
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pub fn build(repo: &Repo, loaded: &Loaded, prefix: &str, format: Format, dest: &Path) -> anyhow::Result<()> {
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    if let Some(dir) = dest.parent() {
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        std::fs::create_dir_all(dir)?;
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    }
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    let tmp = dest.with_extension("partial");
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    let files = entries(repo, loaded)?;
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    match format {
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        Format::TarZst => {
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            let out = std::fs::File::create(&tmp)?;
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            let enc = zstd::Encoder::new(out, 19)?;
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            let mut tar = tar::Builder::new(enc);
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            for (path, bytes, exec, symlink) in &files {
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                let name = format!("{prefix}/{path}");
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                let mut h = tar::Header::new_gnu();
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                h.set_mtime(0);
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                if *symlink {
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                    h.set_entry_type(tar::EntryType::Symlink);
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                    h.set_size(0);
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                    h.set_mode(0o777);
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                    tar.append_link(&mut h, &name, String::from_utf8_lossy(bytes).as_ref())?;
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                } else {
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                    h.set_size(bytes.len() as u64);
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                    h.set_mode(if *exec { 0o755 } else { 0o644 });
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                    tar.append_data(&mut h, &name, bytes.as_slice())?;
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                }
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            }
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            tar.into_inner()?.finish()?.flush()?;
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        }
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        Format::Zip => {
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            let out = std::fs::File::create(&tmp)?;
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            let mut zip = zip::ZipWriter::new(out);
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            for (path, bytes, exec, symlink) in &files {
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                let name = format!("{prefix}/{path}");
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                let opts = zip::write::SimpleFileOptions::default()
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                    .compression_method(zip::CompressionMethod::Deflated)
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                    .unix_permissions(if *exec { 0o755 } else { 0o644 });
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                if *symlink {
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                    zip.add_symlink(name, String::from_utf8_lossy(bytes).as_ref(), opts)?;
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                } else {
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                    zip.start_file(name, opts)?;
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                    zip.write_all(bytes)?;
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                }
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            }
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            zip.finish()?.flush()?;
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        }
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    }
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    std::fs::rename(&tmp, dest)?;
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    Ok(())
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}
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/// Where the cached archive of a state lives.
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pub fn cache_path(data: &Path, state: &str, prefix: &str, format: Format) -> PathBuf {
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    data.join("cache").join("archives").join(format!("{state}-{prefix}.{}", format.ext()))
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}