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Differential D12581

rust-dirstate-v2: clean up previous data file after the docket is written
ClosedPublic

Authored by Alphare on Apr 21 2022, 9:40 AM.

Details

Reviewers
None
Group Reviewers
hg-reviewers
Commits
rHG802e2c25dab8: rust-dirstate-v2: clean up previous data file after the docket is written
Summary

This was overlooked before and caused many data files to keep living forever.
We could potentially consider adding a random cleanup of them in case they
slipped through one day.

Diff Detail

Repository
rHG Mercurial
Lint
Automatic diff as part of commit; lint not applicable.
Unit
Automatic diff as part of commit; unit tests not applicable.

Revision Contents
Changeset List

PathPackages
Mrust/hg-core/src/repo.rs (30 lines)

Diff 33306

rust/hg-core/src/repo.rs

/// ///
/// TODO: have a `WritableRepo` type only accessible while holding the /// TODO: have a `WritableRepo` type only accessible while holding the
/// lock? /// lock?
pub fn write_dirstate(&self) -> Result<(), DirstateError> { pub fn write_dirstate(&self) -> Result<(), DirstateError> {
let map = self.dirstate_map()?; let map = self.dirstate_map()?;
// TODO: Maintain a `DirstateMap::dirty` flag, and return early here if // TODO: Maintain a `DirstateMap::dirty` flag, and return early here if
// it’s unset // it’s unset
let parents = self.dirstate_parents()?; let parents = self.dirstate_parents()?;
let packed_dirstate = if self.has_dirstate_v2() { let (packed_dirstate, old_uuid_to_remove) = if self.has_dirstate_v2() {
let uuid = self.dirstate_data_file_uuid.get_or_init(self)?; let uuid = self.dirstate_data_file_uuid.get_or_init(self)?;
let mut uuid = uuid.as_ref(); let mut uuid = uuid.as_ref();
let can_append = uuid.is_some(); let can_append = uuid.is_some();
let (data, tree_metadata, append, old_data_size) = let (data, tree_metadata, append, old_data_size) =
map.pack_v2(can_append)?; map.pack_v2(can_append)?;
if !append { if !append {
uuid = None uuid = None
} }
let uuid = if let Some(uuid) = uuid { let (uuid, old_uuid) = if let Some(uuid) = uuid {
std::str::from_utf8(uuid) let as_str = std::str::from_utf8(uuid)
.map_err(|_| { .map_err(|_| {
HgError::corrupted("non-UTF-8 dirstate data file ID") HgError::corrupted("non-UTF-8 dirstate data file ID")
})? })?
.to_owned() .to_owned();
let old_uuid_to_remove = Some(as_str.to_owned());
(as_str, old_uuid_to_remove)
} else { } else {
DirstateDocket::new_uid() (DirstateDocket::new_uid(), None)
}; };
let data_filename = format!("dirstate.{}", uuid); let data_filename = format!("dirstate.{}", uuid);
let data_filename = self.hg_vfs().join(data_filename); let data_filename = self.hg_vfs().join(data_filename);
let mut options = std::fs::OpenOptions::new(); let mut options = std::fs::OpenOptions::new();
if append { if append {
options.append(true); options.append(true);
} else { } else {
options.write(true).create_new(true); options.write(true).create_new(true);
} else { } else {
file.write_all(&data)?; file.write_all(&data)?;
file.flush()?; file.flush()?;
// TODO: use https://doc.rust-lang.org/std/io/trait.Seek.html#method.stream_position when we require Rust 1.51+ // TODO: use https://doc.rust-lang.org/std/io/trait.Seek.html#method.stream_position when we require Rust 1.51+
file.seek(SeekFrom::Current(0)) file.seek(SeekFrom::Current(0))
} }
})() })()
.when_writing_file(&data_filename)?; .when_writing_file(&data_filename)?;
DirstateDocket::serialize(
let packed_dirstate = DirstateDocket::serialize(
parents, parents,
tree_metadata, tree_metadata,
data_size, data_size,
uuid.as_bytes(), uuid.as_bytes(),
) )
.map_err(|_: std::num::TryFromIntError| { .map_err(|_: std::num::TryFromIntError| {
HgError::corrupted("overflow in dirstate docket serialization") HgError::corrupted("overflow in dirstate docket serialization")
})? })?;
(packed_dirstate, old_uuid)
} else { } else {
map.pack_v1(parents)? (map.pack_v1(parents)?, None)
}; };
self.hg_vfs().atomic_write("dirstate", &packed_dirstate)?;
let vfs = self.hg_vfs();
vfs.atomic_write("dirstate", &packed_dirstate)?;
if let Some(uuid) = old_uuid_to_remove {
// Remove the old data file after the new docket pointing to the
// new data file was written.
vfs.remove_file(format!("dirstate.{}", uuid))?;
}
Ok(()) Ok(())
} }
} }
/// Lazily-initialized component of `Repo` with interior mutability /// Lazily-initialized component of `Repo` with interior mutability
/// ///
/// This differs from `OnceCell` in that the value can still be "deinitialized" /// This differs from `OnceCell` in that the value can still be "deinitialized"
/// later by setting its inner `Option` to `None`. /// later by setting its inner `Option` to `None`.