Merge pull request #30 from tofay/zstd-no-tar

allow users to get ZstdLayerWriter directly

.github/workflows/ci.yml

@@ -34,12 +34,12 @@ jobs:
       - name: Cache build artifacts
         uses: Swatinem/rust-cache@v2
       - name: cargo build
-        run: cargo build --all-targets
+        run: cargo build --all-targets --all-features
       - name: cargo test
-        run: cargo test --all-targets
+        run: cargo test --all-targets --all-features
       # https://github.com/rust-lang/cargo/issues/6669
       - name: cargo test --doc
-        run: cargo test --doc
+        run: cargo test --doc --all-features
   linting:
     name: Lints, pinned toolchain
     runs-on: ubuntu-latest
@@ -56,4 +56,4 @@ jobs:
       - name: cargo fmt (check)
         run: cargo fmt -- --check -l
       - name: cargo clippy (warnings)
-        run: cargo clippy --all-targets -- -D warnings
+        run: cargo clippy --all-targets --all-features -- -D warnings

Cargo.toml

@@ -24,6 +24,7 @@ zstd = { version = "0.13.2", optional = true }
 
 [dev-dependencies]
 anyhow = "1.0.89"
+cap-tempfile = "3.3.0"
 
 [features]
 zstd = ["dep:zstd"]

examples/zstd.rs

@@ -2,34 +2,40 @@
 fn main() {
     use std::{env, path::PathBuf};
 
+    use cap_tempfile::TempDir;
     use oci_spec::image::Platform;
-    use ocidir::{cap_std::fs::Dir, new_empty_manifest, OciDir};
-    let dir = Dir::open_ambient_dir(env::temp_dir(), ocidir::cap_std::ambient_authority()).unwrap();
-    let oci_dir = OciDir::ensure(&dir).unwrap();
+    use ocidir::{new_empty_manifest, OciDir};
+    let dir = TempDir::new(ocidir::cap_std::ambient_authority()).unwrap();
+    let oci_dir = OciDir::ensure(dir.try_clone().unwrap()).unwrap();
 
     let mut manifest = new_empty_manifest().build().unwrap();
     let mut config = ocidir::oci_spec::image::ImageConfigurationBuilder::default()
         .build()
         .unwrap();
 
     // Add the src as a layer
-    let mut writer = oci_dir.create_layer_zstd(Some(0)).unwrap();
-    writer
+    let writer = oci_dir.create_layer_zstd(Some(0)).unwrap();
+    let mut builder = tar::Builder::new(writer);
+    builder.follow_symlinks(false);
+
+    builder
         .append_dir_all(".", PathBuf::from(env!("CARGO_MANIFEST_DIR")).join("src"))
         .unwrap();
 
-    let layer = writer.into_inner().unwrap().complete().unwrap();
+    let layer = builder.into_inner().unwrap().complete().unwrap();
     oci_dir.push_layer(&mut manifest, &mut config, layer, "src", None);
 
     // Add the examples as a layer, using multithreaded compression
-    let mut writer = oci_dir.create_layer_zstd_multithread(Some(0), 4).unwrap();
-    writer
+    let writer = oci_dir.create_layer_zstd_multithread(Some(0), 4).unwrap();
+    let mut builder = tar::Builder::new(writer);
+    builder.follow_symlinks(false);
+    builder
         .append_dir_all(
             ".",
             PathBuf::from(env!("CARGO_MANIFEST_DIR")).join("examples"),
         )
         .unwrap();
-    let layer = writer.into_inner().unwrap().complete().unwrap();
+    let layer = builder.into_inner().unwrap().complete().unwrap();
     oci_dir.push_layer(&mut manifest, &mut config, layer, "examples", None);
 
     println!(

src/lib.rs

@@ -276,22 +276,18 @@ impl OciDir {
     }
 
     #[cfg(feature = "zstd")]
-    /// Create a tar output stream, backed by a zstd compressed blob
+    /// Create a writer for a new zstd+tar blob; the contents
+    /// are not parsed, but are expected to be a tarball.
     ///
     /// This method is only available when the `zstd` feature is enabled.
-    pub fn create_layer_zstd(
-        &self,
-        compression_level: Option<i32>,
-    ) -> Result<tar::Builder<ZstdLayerWriter>> {
-        Ok(tar::Builder::new(ZstdLayerWriter::new(
-            &self.dir,
-            compression_level,
-        )?))
+    pub fn create_layer_zstd(&self, compression_level: Option<i32>) -> Result<ZstdLayerWriter> {
+        ZstdLayerWriter::new(&self.dir, compression_level)
     }
 
     #[cfg(feature = "zstdmt")]
-    /// Create a tar output stream, backed by a zstd compressed blob
-    /// using multithreaded compression.
+    /// Create a writer for a new zstd+tar blob; the contents
+    /// are not parsed, but are expected to be a tarball.
+    /// The compression is multithreaded.
     ///
     /// The `n_workers` parameter specifies the number of threads to use for compression, per
     /// [zstd::Encoder::multithread]]
@@ -301,12 +297,8 @@ impl OciDir {
         &self,
         compression_level: Option<i32>,
         n_workers: u32,
-    ) -> Result<tar::Builder<ZstdLayerWriter>> {
-        Ok(tar::Builder::new(ZstdLayerWriter::multithread(
-            &self.dir,
-            compression_level,
-            n_workers,
-        )?))
+    ) -> Result<ZstdLayerWriter> {
+        ZstdLayerWriter::multithread(&self.dir, compression_level, n_workers)
     }
 
     /// Add a layer to the top of the image stack.  The firsh pushed layer becomes the root.