1 files changed, 190 insertions, 0 deletions
diff --git a/vendor/gix-features/src/hash.rs b/vendor/gix-features/src/hash.rs
new file mode 100644
index 000000000..fe064139a
--- /dev/null
+++ b/vendor/gix-features/src/hash.rs
@@ -0,0 +1,190 @@
+//! Hash functions and hash utilities
+//!
+//! With the `fast-sha1` feature, the `Sha1` hash type will use a more elaborate implementation utilizing hardware support
+//! in case it is available. Otherwise the `rustsha1` feature should be set. `fast-sha1` will take precedence.
+//! Otherwise, a minimal yet performant implementation is used instead for a decent trade-off between compile times and run-time performance.
+#[cfg(all(feature = "rustsha1", not(feature = "fast-sha1")))]
+mod _impl {
+    use super::Sha1Digest;
+
+    /// A implementation of the Sha1 hash, which can be used once.
+    #[derive(Default, Clone)]
+    pub struct Sha1(sha1_smol::Sha1);
+
+    impl Sha1 {
+        /// Digest the given `bytes`.
+        pub fn update(&mut self, bytes: &[u8]) {
+            self.0.update(bytes)
+        }
+        /// Finalize the hash and produce a digest.
+        pub fn digest(self) -> Sha1Digest {
+            self.0.digest().bytes()
+        }
+    }
+}
+
+/// A 20 bytes digest produced by a [`Sha1`] hash implementation.
+#[cfg(any(feature = "fast-sha1", feature = "rustsha1"))]
+pub type Sha1Digest = [u8; 20];
+
+#[cfg(feature = "fast-sha1")]
+mod _impl {
+    use sha1::Digest;
+
+    use super::Sha1Digest;
+
+    /// A implementation of the Sha1 hash, which can be used once.
+    #[derive(Default, Clone)]
+    pub struct Sha1(sha1::Sha1);
+
+    impl Sha1 {
+        /// Digest the given `bytes`.
+        pub fn update(&mut self, bytes: &[u8]) {
+            self.0.update(bytes)
+        }
+        /// Finalize the hash and produce a digest.
+        pub fn digest(self) -> Sha1Digest {
+            self.0.finalize().into()
+        }
+    }
+}
+
+#[cfg(any(feature = "rustsha1", feature = "fast-sha1"))]
+pub use _impl::Sha1;
+
+/// Compute a CRC32 hash from the given `bytes`, returning the CRC32 hash.
+///
+/// When calling this function for the first time, `previous_value` should be `0`. Otherwise it
+/// should be the previous return value of this function to provide a hash of multiple sequential
+/// chunks of `bytes`.
+#[cfg(feature = "crc32")]
+pub fn crc32_update(previous_value: u32, bytes: &[u8]) -> u32 {
+    let mut h = crc32fast::Hasher::new_with_initial(previous_value);
+    h.update(bytes);
+    h.finalize()
+}
+
+/// Compute a CRC32 value of the given input `bytes`.
+///
+/// In case multiple chunks of `bytes` are present, one should use [`crc32_update()`] instead.
+#[cfg(feature = "crc32")]
+pub fn crc32(bytes: &[u8]) -> u32 {
+    let mut h = crc32fast::Hasher::new();
+    h.update(bytes);
+    h.finalize()
+}
+
+/// Produce a hasher suitable for the given kind of hash.
+#[cfg(any(feature = "rustsha1", feature = "fast-sha1"))]
+pub fn hasher(kind: gix_hash::Kind) -> Sha1 {
+    match kind {
+        gix_hash::Kind::Sha1 => Sha1::default(),
+    }
+}
+
+/// Compute the hash of `kind` for the bytes in the file at `path`, hashing only the first `num_bytes_from_start`
+/// while initializing and calling `progress`.
+///
+/// `num_bytes_from_start` is useful to avoid reading trailing hashes, which are never part of the hash itself,
+/// denoting the amount of bytes to hash starting from the beginning of the file.
+///
+/// # Note
+///
+/// * Only available with the `gix-object` feature enabled due to usage of the [`gix_hash::Kind`] enum and the
+///   [`gix_hash::ObjectId`] return value.
+/// * [Interrupts][crate::interrupt] are supported.
+#[cfg(all(feature = "progress", any(feature = "rustsha1", feature = "fast-sha1")))]
+pub fn bytes_of_file(
+    path: impl AsRef<std::path::Path>,
+    num_bytes_from_start: usize,
+    kind: gix_hash::Kind,
+    progress: &mut impl crate::progress::Progress,
+    should_interrupt: &std::sync::atomic::AtomicBool,
+) -> std::io::Result<gix_hash::ObjectId> {
+    bytes(
+        std::fs::File::open(path)?,
+        num_bytes_from_start,
+        kind,
+        progress,
+        should_interrupt,
+    )
+}
+
+/// Similar to [`bytes_of_file`], but operates on an already open file.
+#[cfg(all(feature = "progress", any(feature = "rustsha1", feature = "fast-sha1")))]
+pub fn bytes(
+    mut read: impl std::io::Read,
+    num_bytes_from_start: usize,
+    kind: gix_hash::Kind,
+    progress: &mut impl crate::progress::Progress,
+    should_interrupt: &std::sync::atomic::AtomicBool,
+) -> std::io::Result<gix_hash::ObjectId> {
+    let mut hasher = hasher(kind);
+    let start = std::time::Instant::now();
+    // init progress before the possibility for failure, as convenience in case people want to recover
+    progress.init(Some(num_bytes_from_start), crate::progress::bytes());
+
+    const BUF_SIZE: usize = u16::MAX as usize;
+    let mut buf = [0u8; BUF_SIZE];
+    let mut bytes_left = num_bytes_from_start;
+
+    while bytes_left > 0 {
+        let out = &mut buf[..BUF_SIZE.min(bytes_left)];
+        read.read_exact(out)?;
+        bytes_left -= out.len();
+        progress.inc_by(out.len());
+        hasher.update(out);
+        if should_interrupt.load(std::sync::atomic::Ordering::SeqCst) {
+            return Err(std::io::Error::new(std::io::ErrorKind::Other, "Interrupted"));
+        }
+    }
+
+    let id = gix_hash::ObjectId::from(hasher.digest());
+    progress.show_throughput(start);
+    Ok(id)
+}
+
+#[cfg(any(feature = "rustsha1", feature = "fast-sha1"))]
+mod write {
+    use crate::hash::Sha1;
+
+    /// A utility to automatically generate a hash while writing into an inner writer.
+    pub struct Write<T> {
+        /// The hash implementation.
+        pub hash: Sha1,
+        /// The inner writer.
+        pub inner: T,
+    }
+
+    impl<T> std::io::Write for Write<T>
+    where
+        T: std::io::Write,
+    {
+        fn write(&mut self, buf: &[u8]) -> std::io::Result<usize> {
+            let written = self.inner.write(buf)?;
+            self.hash.update(&buf[..written]);
+            Ok(written)
+        }
+
+        fn flush(&mut self) -> std::io::Result<()> {
+            self.inner.flush()
+        }
+    }
+
+    impl<T> Write<T>
+    where
+        T: std::io::Write,
+    {
+        /// Create a new hash writer which hashes all bytes written to `inner` with a hash of `kind`.
+        pub fn new(inner: T, object_hash: gix_hash::Kind) -> Self {
+            match object_hash {
+                gix_hash::Kind::Sha1 => Write {
+                    inner,
+                    hash: Sha1::default(),
+                },
+            }
+        }
+    }
+}
+#[cfg(any(feature = "rustsha1", feature = "fast-sha1"))]
+pub use write::Write;