use std::{    path::Path,    sync::atomic::{AtomicBool, Ordering},}; use gix_features::progress::DynNestedProgress; use crate::fetch::{    Arguments, Context, Error, Negotiate, NegotiateOutcome, Options, Outcome, ProgressId, Shallow, Tags, negotiate,};#[crate::bisync::only_async]use crate::transport::client::async_io::{ExtendedBufRead, HandleProgress, Transport};#[crate::bisync::only_sync]use crate::transport::client::blocking_io::{ExtendedBufRead, HandleProgress, Transport}; /// Perform one fetch operation, relying on a `transport`./// `negotiate` is used to run the negotiation of objects that should be contained in the pack, *if* one is to be received./// `progress` and `should_interrupt` is passed to all potentially long-running parts of the operation.////// `consume_pack(pack_read, progress, interrupt) -> bool` is always called to consume all bytes that are sent by the server, returning `true` if we should assure the pack is read to the end,/// or `false` to do nothing. Dropping the reader without reading to EOF (i.e. returning `false`) is an offense to the server, and/// `transport` won't be in the correct state to perform additional operations, or indicate the end of operation./// Note that the passed reader blocking as the pack-writing is blocking as well.////// The `Context` and `Options` further define parts of this `fetch` operation.////// As opposed to a full `git fetch`, this operation does *not*…////// * …update local refs/// * …end the interaction after the fetch////// **Note that the interaction will never be ended**, even on error or failure, leaving it up to the caller to do that, maybe/// with the help of [`SendFlushOnDrop`](crate::SendFlushOnDrop) which can wrap `transport`./// Generally, the `transport` is left in a state that allows for more commands to be run.////// Return `Ok(None)` if there was nothing to do because all remote refs are at the same state as they are locally,/// or there was nothing wanted, or `Ok(Some(outcome))` to inform about all the changes that were made.#[crate::bisync::bisync]pub async fn fetch<P, T, E>(    negotiate: &mut impl Negotiate,    consume_pack: impl FnOnce(&mut dyn std::io::BufRead, &mut dyn DynNestedProgress, &AtomicBool) -> Result<bool, E>,    mut progress: P,    should_interrupt: &AtomicBool,    Context {        handshake,        transport,        user_agent,        trace_packetlines,    }: Context<'_, T>,    Options {        shallow_file,        shallow,        tags,        reject_shallow_remote,    }: Options<'_>,) -> Result<Option<Outcome>, Error>where    P: gix_features::progress::NestedProgress,    P::SubProgress: 'static,    T: Transport,    E: Into<Box<dyn std::error::Error + Send + Sync + 'static>>,{    let _span = gix_trace::coarse!("gix_protocol::fetch()");    let v1_shallow_updates = handshake.v1_shallow_updates.take();    let protocol_version = handshake.server_protocol_version;     let fetch = crate::Command::Fetch;    let fetch_features = {        let mut f = fetch.default_features(protocol_version, &handshake.capabilities);        f.push(user_agent);        f    };     crate::fetch::Response::check_required_features(protocol_version, &fetch_features)?;    let sideband_all = fetch_features.iter().any(|(n, _)| *n == "sideband-all");    let mut arguments = Arguments::new(protocol_version, fetch_features, trace_packetlines);    if matches!(tags, Tags::Included) {        if !arguments.can_use_include_tag() {            return Err(Error::MissingServerFeature {                    feature: "include-tag",                    description:                    // NOTE: if this is an issue, we could probably do what's proposed here.                    "To make this work we would have to implement another pass to fetch attached tags separately",                });        }        arguments.use_include_tag();    }    let (shallow_commits, mut shallow_lock) = add_shallow_args(&mut arguments, shallow, &shallow_file)?;     let negotiate_span = gix_trace::detail!(        "negotiate",        protocol_version = handshake.server_protocol_version as usize    );    let action = negotiate.mark_complete_and_common_ref()?;    let mut previous_response = None::<crate::fetch::Response>;    match &action {        negotiate::Action::NoChange | negotiate::Action::SkipToRefUpdate => Ok(None),        negotiate::Action::MustNegotiate {            remote_ref_target_known,        } => {            if !negotiate.add_wants(&mut arguments, remote_ref_target_known) {                return Ok(None);            }            let mut rounds = Vec::new();            let is_stateless = arguments.is_stateless(!transport.connection_persists_across_multiple_requests());            let mut state = negotiate::one_round::State::new(is_stateless);            let reader = 'negotiation: loop {                let _round = gix_trace::detail!("negotiate round", round = rounds.len() + 1);                progress.step();                progress.set_name(format!("negotiate (round {})", rounds.len() + 1));                if should_interrupt.load(Ordering::Relaxed) {                    return Err(Error::Negotiate(negotiate::Error::NegotiationFailed {                        rounds: rounds.len(),                    }));                }                 let is_done = match negotiate.one_round(&mut state, &mut arguments, previous_response.as_ref()) {                    Ok((round, is_done)) => {                        rounds.push(round);                        is_done                    }                    Err(err) => {                        return Err(err.into());                    }                };                let mut reader = arguments.send(transport, is_done).await?;                if sideband_all {                    setup_remote_progress(&mut progress, &mut reader, should_interrupt);                }                let response =                    crate::fetch::Response::from_line_reader(protocol_version, &mut reader, is_done, !is_done).await?;                let has_pack = response.has_pack();                previous_response = Some(response);                if has_pack {                    progress.step();                    progress.set_name("receiving pack".into());                    if !sideband_all {                        setup_remote_progress(&mut progress, &mut reader, should_interrupt);                    }                    break 'negotiation reader;                }            };            // This needs drop if tracing is compiled in. We just don't know it.            drop(negotiate_span);             let mut previous_response = previous_response.expect("knowledge of a pack means a response was received");            previous_response.append_v1_shallow_updates(v1_shallow_updates);            if !previous_response.shallow_updates().is_empty() && shallow_lock.is_none() {                if reject_shallow_remote {                    return Err(Error::RejectShallowRemote);                }                shallow_lock = acquire_shallow_lock(&shallow_file).map(Some)?;            }             let (mut reader, may_read_to_end) =                consume_received_pack(reader, consume_pack, &mut progress, should_interrupt)?;             if may_read_to_end {                // Assure the final flush packet is consumed.                let has_read_to_end = reader.stopped_at().is_some();                if !has_read_to_end {                    read_remaining(&mut reader).await.map_err(Error::ReadRemainingBytes)?;                }            }            drop(reader);             if let Some(shallow_lock) = shallow_lock                && !previous_response.shallow_updates().is_empty()            {                gix_shallow::write(shallow_lock, shallow_commits, previous_response.shallow_updates())?;            }            Ok(Some(Outcome {                last_response: previous_response,                negotiate: NegotiateOutcome { action, rounds },            }))        }    }} #[crate::bisync::only_async]fn consume_received_pack<R, E>(    reader: R,    consume: impl FnOnce(&mut dyn std::io::BufRead, &mut dyn DynNestedProgress, &AtomicBool) -> Result<bool, E>,    progress: &mut dyn DynNestedProgress,    should_interrupt: &AtomicBool,) -> Result<(R, bool), Error>where    R: crate::futures_io::AsyncBufRead + Unpin,    E: Into<Box<dyn std::error::Error + Send + Sync + 'static>>,{    let mut reader = crate::futures_lite::io::BlockOn::new(reader);    let may_read_to_end =        consume(&mut reader, progress, should_interrupt).map_err(|err| Error::ConsumePack(err.into()))?;    Ok((reader.into_inner(), may_read_to_end))} #[crate::bisync::only_sync]fn consume_received_pack<R, E>(    mut reader: R,    consume: impl FnOnce(&mut dyn std::io::BufRead, &mut dyn DynNestedProgress, &AtomicBool) -> Result<bool, E>,    progress: &mut dyn DynNestedProgress,    should_interrupt: &AtomicBool,) -> Result<(R, bool), Error>where    R: std::io::BufRead,    E: Into<Box<dyn std::error::Error + Send + Sync + 'static>>,{    let may_read_to_end =        consume(&mut reader, progress, should_interrupt).map_err(|err| Error::ConsumePack(err.into()))?;    Ok((reader, may_read_to_end))} #[crate::bisync::only_async]async fn read_remaining(reader: &mut (impl crate::futures_io::AsyncRead + Unpin)) -> std::io::Result<()> {    crate::futures_lite::io::copy(reader, &mut crate::futures_lite::io::sink())        .await        .map(|_| ())} #[crate::bisync::only_sync]fn read_remaining(reader: &mut impl std::io::Read) -> std::io::Result<()> {    std::io::copy(reader, &mut std::io::sink()).map(|_| ())} fn acquire_shallow_lock(shallow_file: &Path) -> Result<gix_lock::File, Error> {    gix_lock::File::acquire_to_update_resource(shallow_file, gix_lock::acquire::Fail::Immediately, None, 0)        .map_err(Into::into)} fn add_shallow_args(    args: &mut Arguments,    shallow: &Shallow,    shallow_file: &std::path::Path,) -> Result<(Option<nonempty::NonEmpty<gix_hash::ObjectId>>, Option<gix_lock::File>), Error> {    let expect_change = *shallow != Shallow::NoChange;    let shallow_lock = expect_change.then(|| acquire_shallow_lock(shallow_file)).transpose()?;     let shallow_commits = gix_shallow::read(shallow_file)?;    if (shallow_commits.is_some() || expect_change) && !args.can_use_shallow() {        // NOTE: if this is an issue, we can always unshallow the repo ourselves.        return Err(Error::MissingServerFeature {            feature: "shallow",            description: "shallow clones need server support to remain shallow, otherwise bigger than expected packs are sent effectively unshallowing the repository",        });    }    if let Some(shallow_commits) = &shallow_commits {        for commit in shallow_commits.iter() {            args.shallow(commit);        }    }    match shallow {        Shallow::NoChange => {}        Shallow::DepthAtRemote(commits) => args.deepen(commits.get() as usize),        Shallow::Deepen(commits) => {            args.deepen(*commits as usize);            args.deepen_relative();        }        Shallow::Since { cutoff } => {            args.deepen_since(cutoff.seconds);        }        Shallow::Exclude {            remote_refs,            since_cutoff,        } => {            if let Some(cutoff) = since_cutoff {                args.deepen_since(cutoff.seconds);            }            for ref_ in remote_refs {                args.deepen_not(ref_.as_ref().as_bstr());            }        }    }    Ok((shallow_commits, shallow_lock))} fn setup_remote_progress<'a>(    progress: &mut dyn gix_features::progress::DynNestedProgress,    reader: &mut Box<dyn ExtendedBufRead<'a> + Unpin + 'a>,    should_interrupt: &'a AtomicBool,) {    reader.set_progress_handler(Some(Box::new({        let mut remote_progress = progress.add_child_with_id("remote".to_string(), ProgressId::RemoteProgress.into());        move |is_err: bool, data: &[u8]| {            crate::RemoteProgress::translate_to_progress(is_err, data, &mut remote_progress);            if should_interrupt.load(Ordering::Relaxed) {                std::ops::ControlFlow::Break(())            } else {                std::ops::ControlFlow::Continue(())            }        }    }) as HandleProgress<'a>));}