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#![allow(clippy::result_large_err)]
use std::convert::TryInto;
use std::ops::DerefMut;
use gix_hash::ObjectId;
use gix_odb::{Find, FindExt, Write};
use gix_ref::{
transaction::{LogChange, PreviousValue, RefLog},
FullName,
};
use crate::{commit, ext::ObjectIdExt, object, tag, Id, Object, Reference, Tree};
/// Methods related to object creation.
impl crate::Repository {
/// Find the object with `id` in the object database or return an error if it could not be found.
///
/// There are various legitimate reasons for an object to not be present, which is why
/// [`try_find_object(…)`][crate::Repository::try_find_object()] might be preferable instead.
///
/// # Performance Note
///
/// In order to get the kind of the object, is must be fully decoded from storage if it is packed with deltas.
/// Loose object could be partially decoded, even though that's not implemented.
pub fn find_object(&self, id: impl Into<ObjectId>) -> Result<Object<'_>, object::find::existing::Error> {
let id = id.into();
if id == gix_hash::ObjectId::empty_tree(self.object_hash()) {
return Ok(Object {
id,
kind: gix_object::Kind::Tree,
data: Vec::new(),
repo: self,
});
}
let mut buf = self.free_buf();
let kind = self.objects.find(id, &mut buf)?.kind;
Ok(Object::from_data(id, kind, buf, self))
}
/// Try to find the object with `id` or return `None` if it wasn't found.
pub fn try_find_object(&self, id: impl Into<ObjectId>) -> Result<Option<Object<'_>>, object::find::Error> {
let id = id.into();
if id == gix_hash::ObjectId::empty_tree(self.object_hash()) {
return Ok(Some(Object {
id,
kind: gix_object::Kind::Tree,
data: Vec::new(),
repo: self,
}));
}
let mut buf = self.free_buf();
match self.objects.try_find(id, &mut buf)? {
Some(obj) => {
let kind = obj.kind;
Ok(Some(Object::from_data(id, kind, buf, self)))
}
None => Ok(None),
}
}
fn shared_empty_buf(&self) -> std::cell::RefMut<'_, Vec<u8>> {
let mut bufs = self.bufs.borrow_mut();
if bufs.last().is_none() {
bufs.push(Vec::with_capacity(512));
}
std::cell::RefMut::map(bufs, |bufs| {
let buf = bufs.last_mut().expect("we assure one is present");
buf.clear();
buf
})
}
/// Write the given object into the object database and return its object id.
///
/// Note that we hash the object in memory to avoid storing objects that are already present. That way,
/// we avoid writing duplicate objects using slow disks that will eventually have to be garbage collected.
pub fn write_object(&self, object: impl gix_object::WriteTo) -> Result<Id<'_>, object::write::Error> {
let mut buf = self.shared_empty_buf();
object.write_to(buf.deref_mut())?;
let oid = gix_object::compute_hash(self.object_hash(), object.kind(), &buf);
if self.objects.contains(oid) {
return Ok(oid.attach(self));
}
self.objects
.write_buf(object.kind(), &buf)
.map(|oid| oid.attach(self))
.map_err(Into::into)
}
/// Write a blob from the given `bytes`.
///
/// We avoid writing duplicate objects to slow disks that will eventually have to be garbage collected by
/// pre-hashing the data, and checking if the object is already present.
pub fn write_blob(&self, bytes: impl AsRef<[u8]>) -> Result<Id<'_>, object::write::Error> {
let bytes = bytes.as_ref();
let oid = gix_object::compute_hash(self.object_hash(), gix_object::Kind::Blob, bytes);
if self.objects.contains(oid) {
return Ok(oid.attach(self));
}
self.objects
.write_buf(gix_object::Kind::Blob, bytes)
.map(|oid| oid.attach(self))
}
/// Write a blob from the given `Read` implementation.
///
/// Note that we hash the object in memory to avoid storing objects that are already present. That way,
/// we avoid writing duplicate objects using slow disks that will eventually have to be garbage collected.
///
/// If that is prohibitive, use the object database directly.
pub fn write_blob_stream(
&self,
mut bytes: impl std::io::Read + std::io::Seek,
) -> Result<Id<'_>, object::write::Error> {
let mut buf = self.shared_empty_buf();
std::io::copy(&mut bytes, buf.deref_mut())?;
let oid = gix_object::compute_hash(self.object_hash(), gix_object::Kind::Blob, &buf);
if self.objects.contains(oid) {
return Ok(oid.attach(self));
}
self.objects
.write_buf(gix_object::Kind::Blob, &buf)
.map(|oid| oid.attach(self))
}
/// Create a tag reference named `name` (without `refs/tags/` prefix) pointing to a newly created tag object
/// which in turn points to `target` and return the newly created reference.
///
/// It will be created with `constraint` which is most commonly to [only create it][PreviousValue::MustNotExist]
/// or to [force overwriting a possibly existing tag](PreviousValue::Any).
pub fn tag(
&self,
name: impl AsRef<str>,
target: impl AsRef<gix_hash::oid>,
target_kind: gix_object::Kind,
tagger: Option<gix_actor::SignatureRef<'_>>,
message: impl AsRef<str>,
constraint: PreviousValue,
) -> Result<Reference<'_>, tag::Error> {
let tag = gix_object::Tag {
target: target.as_ref().into(),
target_kind,
name: name.as_ref().into(),
tagger: tagger.map(|t| t.to_owned()),
message: message.as_ref().into(),
pgp_signature: None,
};
let tag_id = self.write_object(&tag)?;
self.tag_reference(name, tag_id, constraint).map_err(Into::into)
}
/// Similar to [`commit(…)`][crate::Repository::commit()], but allows to create the commit with `committer` and `author` specified.
///
/// This forces setting the commit time and author time by hand. Note that typically, committer and author are the same.
pub fn commit_as<'a, 'c, Name, E>(
&self,
committer: impl Into<gix_actor::SignatureRef<'c>>,
author: impl Into<gix_actor::SignatureRef<'a>>,
reference: Name,
message: impl AsRef<str>,
tree: impl Into<ObjectId>,
parents: impl IntoIterator<Item = impl Into<ObjectId>>,
) -> Result<Id<'_>, commit::Error>
where
Name: TryInto<FullName, Error = E>,
commit::Error: From<E>,
{
use gix_ref::{
transaction::{Change, RefEdit},
Target,
};
// TODO: possibly use CommitRef to save a few allocations (but will have to allocate for object ids anyway.
// This can be made vastly more efficient though if we wanted to, so we lie in the API
let reference = reference.try_into()?;
let commit = gix_object::Commit {
message: message.as_ref().into(),
tree: tree.into(),
author: author.into().to_owned(),
committer: committer.into().to_owned(),
encoding: None,
parents: parents.into_iter().map(|id| id.into()).collect(),
extra_headers: Default::default(),
};
let commit_id = self.write_object(&commit)?;
self.edit_reference(RefEdit {
change: Change::Update {
log: LogChange {
mode: RefLog::AndReference,
force_create_reflog: false,
message: crate::reference::log::message("commit", commit.message.as_ref(), commit.parents.len()),
},
expected: match commit.parents.first().map(|p| Target::Peeled(*p)) {
Some(previous) => {
if reference.as_bstr() == "HEAD" {
PreviousValue::MustExistAndMatch(previous)
} else {
PreviousValue::ExistingMustMatch(previous)
}
}
None => PreviousValue::MustNotExist,
},
new: Target::Peeled(commit_id.inner),
},
name: reference,
deref: true,
})?;
Ok(commit_id)
}
/// Create a new commit object with `message` referring to `tree` with `parents`, and point `reference`
/// to it. The commit is written without message encoding field, which can be assumed to be UTF-8.
/// `author` and `committer` fields are pre-set from the configuration, which can be altered
/// [temporarily][crate::Repository::config_snapshot_mut()] before the call if required.
///
/// `reference` will be created if it doesn't exist, and can be `"HEAD"` to automatically write-through to the symbolic reference
/// that `HEAD` points to if it is not detached. For this reason, detached head states cannot be created unless the `HEAD` is detached
/// already. The reflog will be written as canonical git would do, like `<operation> (<detail>): <summary>`.
///
/// The first parent id in `parents` is expected to be the current target of `reference` and the operation will fail if it is not.
/// If there is no parent, the `reference` is expected to not exist yet.
///
/// The method fails immediately if a `reference` lock can't be acquired.
pub fn commit<Name, E>(
&self,
reference: Name,
message: impl AsRef<str>,
tree: impl Into<ObjectId>,
parents: impl IntoIterator<Item = impl Into<ObjectId>>,
) -> Result<Id<'_>, commit::Error>
where
Name: TryInto<FullName, Error = E>,
commit::Error: From<E>,
{
let author = self.author().ok_or(commit::Error::AuthorMissing)??;
let committer = self.committer().ok_or(commit::Error::CommitterMissing)??;
self.commit_as(committer, author, reference, message, tree, parents)
}
/// Return an empty tree object, suitable for [getting changes](crate::Tree::changes()).
///
/// Note that it is special and doesn't physically exist in the object database even though it can be returned.
/// This means that this object can be used in an uninitialized, empty repository which would report to have no objects at all.
pub fn empty_tree(&self) -> Tree<'_> {
self.find_object(gix_hash::ObjectId::empty_tree(self.object_hash()))
.expect("always present")
.into_tree()
}
}
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