223 lines · 8.5 KB · Rust
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use std::{    convert::TryInto,    path::PathBuf,    sync::atomic::{AtomicBool, Ordering},    time::{Instant, SystemTime},}; use git_features::progress::Progress; use crate::multi_index; mod error {    /// The error returned by [multi_index::File::write_from_index_paths()][super::multi_index::File::write_from_index_paths()]..    #[derive(Debug, thiserror::Error)]    #[allow(missing_docs)]    pub enum Error {        #[error(transparent)]        Io(#[from] std::io::Error),        #[error("Interrupted")]        Interrupted,        #[error(transparent)]        OpenIndex(#[from] crate::index::init::Error),    }}pub use error::Error; /// An entry suitable for sorting and writingpub(crate) struct Entry {    pub(crate) id: git_hash::ObjectId,    pub(crate) pack_index: u32,    pub(crate) pack_offset: crate::data::Offset,    /// Used for sorting in case of duplicates    index_mtime: SystemTime,} /// Options for use in [`multi_index::File::write_from_index_paths()`].pub struct Options {    /// The kind of hash to use for objects and to expect in the input files.    pub object_hash: git_hash::Kind,} /// The result of [`multi_index::File::write_from_index_paths()`].pub struct Outcome<P> {    /// The calculated multi-index checksum of the file at `multi_index_path`.    pub multi_index_checksum: git_hash::ObjectId,    /// The input progress    pub progress: P,} impl multi_index::File {    pub(crate) const SIGNATURE: &'static [u8] = b"MIDX";    pub(crate) const HEADER_LEN: usize = 4 /*signature*/ +        1 /*version*/ +        1 /*object id version*/ +        1 /*num chunks */ +        1 /*num base files */ +        4 /*num pack files*/;     /// Create a new multi-index file for writing to `out` from the pack index files at `index_paths`.    ///    /// Progress is sent to `progress` and interruptions checked via `should_interrupt`.    pub fn write_from_index_paths<P>(        mut index_paths: Vec<PathBuf>,        out: impl std::io::Write,        mut progress: P,        should_interrupt: &AtomicBool,        Options { object_hash }: Options,    ) -> Result<Outcome<P>, Error>    where        P: Progress,    {        let out = git_features::hash::Write::new(out, object_hash);        let (index_paths_sorted, index_filenames_sorted) = {            index_paths.sort();            let file_names = index_paths                .iter()                .map(|p| PathBuf::from(p.file_name().expect("file name present")))                .collect::<Vec<_>>();            (index_paths, file_names)        };         let entries = {            let mut entries = Vec::new();            let start = Instant::now();            let mut progress = progress.add_child_with_id("Collecting entries", *b"MPCE"); /* Multiindex from Paths Collecting Entries */            progress.init(Some(index_paths_sorted.len()), git_features::progress::count("indices"));             // This could be parallelized… but it's probably not worth it unless you have 500mio objects.            for (index_id, index) in index_paths_sorted.iter().enumerate() {                let mtime = index                    .metadata()                    .and_then(|m| m.modified())                    .unwrap_or(SystemTime::UNIX_EPOCH);                let index = crate::index::File::at(index, object_hash)?;                 entries.reserve(index.num_objects() as usize);                entries.extend(index.iter().map(|e| Entry {                    id: e.oid,                    pack_index: index_id as u32,                    pack_offset: e.pack_offset,                    index_mtime: mtime,                }));                progress.inc();                if should_interrupt.load(Ordering::Relaxed) {                    return Err(Error::Interrupted);                }            }            progress.show_throughput(start);             let start = Instant::now();            progress.set_name("Deduplicate");            progress.init(Some(entries.len()), git_features::progress::count("entries"));            entries.sort_by(|l, r| {                l.id.cmp(&r.id)                    .then_with(|| l.index_mtime.cmp(&r.index_mtime).reverse())                    .then_with(|| l.pack_index.cmp(&r.pack_index))            });            entries.dedup_by_key(|e| e.id);            progress.inc_by(entries.len());            progress.show_throughput(start);            if should_interrupt.load(Ordering::Relaxed) {                return Err(Error::Interrupted);            }            entries        };         let mut cf = git_chunk::file::Index::for_writing();        cf.plan_chunk(            multi_index::chunk::index_names::ID,            multi_index::chunk::index_names::storage_size(&index_filenames_sorted),        );        cf.plan_chunk(multi_index::chunk::fanout::ID, multi_index::chunk::fanout::SIZE as u64);        cf.plan_chunk(            multi_index::chunk::lookup::ID,            multi_index::chunk::lookup::storage_size(entries.len(), object_hash),        );        cf.plan_chunk(            multi_index::chunk::offsets::ID,            multi_index::chunk::offsets::storage_size(entries.len()),        );         let num_large_offsets = multi_index::chunk::large_offsets::num_large_offsets(&entries);        if let Some(num_large_offsets) = num_large_offsets {            cf.plan_chunk(                multi_index::chunk::large_offsets::ID,                multi_index::chunk::large_offsets::storage_size(num_large_offsets),            );        }         let mut write_progress = progress.add_child_with_id("Writing multi-index", *b"MPBW"); /* Multiindex Bytes Written  */        let write_start = Instant::now();        write_progress.init(            Some(cf.planned_storage_size() as usize + Self::HEADER_LEN),            git_features::progress::bytes(),        );        let mut out = git_features::progress::Write {            inner: out,            progress: write_progress,        };         let bytes_written = Self::write_header(            &mut out,            cf.num_chunks().try_into().expect("BUG: wrote more than 256 chunks"),            index_paths_sorted.len() as u32,            object_hash,        )?;         {            progress.set_name("Writing chunks");            progress.init(Some(cf.num_chunks()), git_features::progress::count("chunks"));             let mut chunk_write = cf.into_write(&mut out, bytes_written)?;            while let Some(chunk_to_write) = chunk_write.next_chunk() {                match chunk_to_write {                    multi_index::chunk::index_names::ID => {                        multi_index::chunk::index_names::write(&index_filenames_sorted, &mut chunk_write)?                    }                    multi_index::chunk::fanout::ID => multi_index::chunk::fanout::write(&entries, &mut chunk_write)?,                    multi_index::chunk::lookup::ID => multi_index::chunk::lookup::write(&entries, &mut chunk_write)?,                    multi_index::chunk::offsets::ID => {                        multi_index::chunk::offsets::write(&entries, num_large_offsets.is_some(), &mut chunk_write)?                    }                    multi_index::chunk::large_offsets::ID => multi_index::chunk::large_offsets::write(                        &entries,                        num_large_offsets.expect("available if planned"),                        &mut chunk_write,                    )?,                    unknown => unreachable!("BUG: forgot to implement chunk {:?}", std::str::from_utf8(&unknown)),                }                progress.inc();                if should_interrupt.load(Ordering::Relaxed) {                    return Err(Error::Interrupted);                }            }        }         // write trailing checksum        let multi_index_checksum: git_hash::ObjectId = out.inner.hash.digest().into();        out.inner.inner.write_all(multi_index_checksum.as_slice())?;        out.progress.show_throughput(write_start);         Ok(Outcome {            multi_index_checksum,            progress,        })    }     fn write_header(        mut out: impl std::io::Write,        num_chunks: u8,        num_indices: u32,        object_hash: git_hash::Kind,    ) -> std::io::Result<usize> {        out.write_all(Self::SIGNATURE)?;        out.write_all(&[crate::multi_index::Version::V1 as u8])?;        out.write_all(&[object_hash as u8])?;        out.write_all(&[num_chunks])?;        out.write_all(&[0])?; /* unused number of base files */        out.write_all(&num_indices.to_be_bytes())?;         Ok(Self::HEADER_LEN)    }}