85 lines · 2.9 KB · Rust
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use crate::store::packed; impl AsRef<[u8]> for packed::Buffer {    fn as_ref(&self) -> &[u8] {        match &self.data {            packed::Backing::InMemory(data) => &data[self.offset..],            packed::Backing::Mapped(map) => &map[self.offset..],        }    }} impl AsRef<[u8]> for packed::Backing {    fn as_ref(&self) -> &[u8] {        match self {            packed::Backing::InMemory(data) => data,            packed::Backing::Mapped(map) => map,        }    }} ///pub mod open {    use crate::store::packed;    use filebuffer::FileBuffer;    use std::path::PathBuf;     /// Initialization    impl packed::Buffer {        /// Open the file at `path` and map it into memory if the file size is larger than `use_memory_map_if_larger_than_bytes`.        ///        /// In order to allow fast lookups and optimizations, the contents of the packed refs must be sorted.        /// If that's not the case, they will be sorted on the fly with the data being written into a memory buffer.        pub fn open(path: impl Into<PathBuf>, use_memory_map_if_larger_than_bytes: u64) -> Result<Self, Error> {            let path = path.into();            let backing = if std::fs::metadata(&path)?.len() <= use_memory_map_if_larger_than_bytes {                packed::Backing::InMemory(std::fs::read(&path)?)            } else {                packed::Backing::Mapped(FileBuffer::open(&path)?)            };             let (offset, sorted) = {                let data = backing.as_ref();                if *data.get(0).unwrap_or(&b' ') == b'#' {                    let (records, header) = packed::decode::header::<()>(data).map_err(|_| Error::HeaderParsing)?;                    let offset = records.as_ptr() as usize - data.as_ptr() as usize;                    (offset, header.sorted)                } else {                    (0, false)                }            };            if !sorted {                return Err(Error::Unsorted);            }            Ok(packed::Buffer {                offset,                data: backing,                path,            })        }    }     mod error {        use quick_error::quick_error;         quick_error! {            /// The error returned by [`open()`][super::packed::Buffer::open()].            #[derive(Debug)]            #[allow(missing_docs)]            pub enum Error {                Unsorted {                    display("The packed-refs file did not have a header or wasn't sorted.")                }                HeaderParsing {                    display("The header could not be parsed, even though first line started with '#'")                }                Io(err: std::io::Error) {                    display("The buffer could not be opened or read")                    from()                    source(err)                }            }        }    }    pub use error::Error;}