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use crate::{
store_impl::file::{transaction::PackedRefs, Transaction},
transaction::{Change, LogChange, RefEdit, RefLog},
Target,
};
impl<'s, 'p> Transaction<'s, 'p> {
/// Make all [prepared][Transaction::prepare()] permanent and return the performed edits which represent the current
/// state of the affected refs in the ref store in that instant. Please note that the obtained edits may have been
/// adjusted to contain more dependent edits or additional information.
/// `committer` is used in the reflog and only if the reflog is actually written, which is why it is optional. Please note
/// that if `None` is passed and the reflog needs to be written, the operation will be aborted late and a few refs may have been
/// successfully committed already, making clear the non-atomic nature of multi-file edits.
///
/// On error the transaction may have been performed partially, depending on the nature of the error, and no attempt to roll back
/// partial changes is made.
///
/// In this stage, we perform the following operations:
///
/// * update the ref log
/// * move updated refs into place
/// * delete reflogs and empty parent directories
/// * delete packed refs
/// * delete their corresponding reference (if applicable)
/// along with empty parent directories
///
/// Note that transactions will be prepared automatically as needed.
pub fn commit<'a>(self, committer: impl Into<Option<git_actor::SignatureRef<'a>>>) -> Result<Vec<RefEdit>, Error> {
self.commit_inner(committer.into())
}
fn commit_inner(self, committer: Option<git_actor::SignatureRef<'_>>) -> Result<Vec<RefEdit>, Error> {
let mut updates = self.updates.expect("BUG: must call prepare before commit");
let delete_loose_refs = matches!(
self.packed_refs,
PackedRefs::DeletionsAndNonSymbolicUpdatesRemoveLooseSourceReference(_)
);
// Perform updates first so live commits remain referenced
for change in updates.iter_mut() {
assert!(!change.update.deref, "Deref mode is turned into splits and turned off");
match &change.update.change {
// reflog first, then reference
Change::Update { log, new, expected } => {
let lock = change.lock.take();
let (update_ref, update_reflog) = match log.mode {
RefLog::Only => (false, true),
RefLog::AndReference => (true, true),
};
if update_reflog {
let log_update = match new {
Target::Symbolic(_) => {
// no reflog for symref changes, unless the ref is new and we can obtain a peeled id
// identified by the expectation of what could be there, as is the case when cloning.
match expected {
PreviousValue::ExistingMustMatch(Target::Peeled(oid)) => {
Some((Some(git_hash::ObjectId::null(oid.kind())), oid))
}
_ => None,
}
}
Target::Peeled(new_oid) => {
let previous = match expected {
PreviousValue::MustExistAndMatch(Target::Peeled(oid)) => Some(oid.to_owned()),
_ => None,
}
.or(change.leaf_referent_previous_oid);
Some((previous, new_oid))
}
};
if let Some((previous, new_oid)) = log_update {
let do_update = previous.as_ref().map_or(true, |previous| previous != new_oid);
if do_update {
self.store.reflog_create_or_append(
change.update.name.as_ref(),
previous,
new_oid,
committer,
log.message.as_ref(),
log.force_create_reflog,
)?;
}
}
}
// Don't do anything else while keeping the lock after potentially updating the reflog.
// We delay deletion of the reference and dropping the lock to after the packed-refs were
// safely written.
if delete_loose_refs && matches!(new, Target::Peeled(_)) {
change.lock = lock;
continue;
}
if update_ref {
if let Some(Err(err)) = lock.map(|l| l.commit()) {
// TODO: when Kind::IsADirectory becomes stable, use that.
let err = if err.instance.resource_path().is_dir() {
git_tempfile::remove_dir::empty_depth_first(err.instance.resource_path())
.map_err(|io_err| std::io::Error::new(std::io::ErrorKind::Other, io_err))
.and_then(|_| err.instance.commit().map_err(|err| err.error))
.err()
} else {
Some(err.error)
};
if let Some(err) = err {
return Err(Error::LockCommit {
source: err,
full_name: change.name(),
});
}
};
}
}
Change::Delete { .. } => {}
}
}
for change in updates.iter_mut() {
let (reflog_root, relative_name) = self.store.reflog_base_and_relative_path(change.update.name.as_ref());
match &change.update.change {
Change::Update { .. } => {}
Change::Delete { .. } => {
// Reflog deletion happens first in case it fails a ref without log is less terrible than
// a log without a reference.
let reflog_path = reflog_root.join(relative_name);
if let Err(err) = std::fs::remove_file(&reflog_path) {
if err.kind() != std::io::ErrorKind::NotFound {
return Err(Error::DeleteReflog {
source: err,
full_name: change.name(),
});
}
} else {
git_tempfile::remove_dir::empty_upward_until_boundary(
reflog_path.parent().expect("never without parent"),
&reflog_root,
)
.ok();
}
}
}
}
if let Some(t) = self.packed_transaction {
t.commit().map_err(Error::PackedTransactionCommit)?;
// Always refresh ourselves right away to avoid races. We ignore errors as there may be many reasons this fails, and it's not
// critical to be done here. In other words, the pack may be refreshed at a later time and then it might work.
self.store.force_refresh_packed_buffer().ok();
}
for change in updates.iter_mut() {
let take_lock_and_delete = match &change.update.change {
Change::Update {
log: LogChange { mode, .. },
new,
..
} => delete_loose_refs && *mode == RefLog::AndReference && matches!(new, Target::Peeled(_)),
Change::Delete { log: mode, .. } => *mode == RefLog::AndReference,
};
if take_lock_and_delete {
let lock = change.lock.take();
let reference_path = self.store.reference_path(change.update.name.as_ref());
if let Err(err) = std::fs::remove_file(reference_path) {
if err.kind() != std::io::ErrorKind::NotFound {
return Err(Error::DeleteReference {
err,
full_name: change.name(),
});
}
}
drop(lock)
}
}
Ok(updates.into_iter().map(|edit| edit.update).collect())
}
}
mod error {
use git_object::bstr::BString;
use crate::store_impl::{file, packed};
/// The error returned by various [`Transaction`][super::Transaction] methods.
#[derive(Debug, thiserror::Error)]
#[allow(missing_docs)]
pub enum Error {
#[error("The packed-ref transaction could not be committed")]
PackedTransactionCommit(#[source] packed::transaction::commit::Error),
#[error("Edit preprocessing failed with error")]
PreprocessingFailed { source: std::io::Error },
#[error("The change for reference {full_name:?} could not be committed")]
LockCommit { source: std::io::Error, full_name: BString },
#[error("The reference {full_name} could not be deleted")]
DeleteReference { full_name: BString, err: std::io::Error },
#[error("The reflog of reference {full_name:?} could not be deleted")]
DeleteReflog { full_name: BString, source: std::io::Error },
#[error("The reflog could not be created or updated")]
CreateOrUpdateRefLog(#[from] file::log::create_or_update::Error),
}
}
pub use error::Error;
use crate::transaction::PreviousValue;