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Differential D7789

rust-revlog: a trait for the revlog index
ClosedPublic

Authored by gracinet on Jan 6 2020, 2:25 PM.

Details

Reviewers
martinvonz
Group Reviewers
hg-reviewers
Commits
rHG3fb39dc2e356: rust-revlog: a trait for the revlog index
Summary

As explained in the doc comment, this is the minimum needed
for our immediate concern, which is to implement a nodemap
in Rust.

The trait will be later implemented in hg-cpython by the
index Python object implemented in C, thanks to exposition
of the corresponding functions as a capsule.

The None return cases in node() match what the index_node()
C function does.

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.

Event Timeline

gracinet created this revision.Jan 6 2020, 2:25 PM
martinvonz added a subscriber: martinvonz.Jan 17 2020, 8:30 PM

The None return cases in node() match what the index_node()
C function does.

You mean the code on https://www.mercurial-scm.org/repo/hg/file/fdaa4233dc18/mercurial/cext/revlog.c#l388? Line 394 there returns nullid, so does that really match? Why not return the nullid when given nullrev as input?

martinvonz requested changes to this revision.Jan 21 2020, 1:03 PM
This revision now requires changes to proceed.Jan 21 2020, 1:03 PM
gracinet added a comment.Jan 23 2020, 3:41 PM

@martinvonz yeah, probably wrote the doc-comment too fast

Of course it's meant to match what revlog.c does, since the first implementation willl actually be re-exposure of the C version

gracinet updated this revision to Diff 19629.Jan 27 2020, 10:49 AM
martinvonz accepted this revision.Jan 27 2020, 1:24 PM
This revision is now accepted and ready to land.Jan 27 2020, 1:24 PM
gracinet added a commit: rHG3fb39dc2e356: rust-revlog: a trait for the revlog index.Jan 27 2020, 1:36 PM
Closed by commit rHG3fb39dc2e356: rust-revlog: a trait for the revlog index (authored by gracinet). · Explain Why
This revision was automatically updated to reflect the committed changes.

Revision Contents
Changeset List

PathPackages
Mrust/hg-core/src/revlog.rs (14 lines)

Diff 19642

rust/hg-core/src/revlog.rs

fn parents(&self, rev: Revision) -> Result<[Revision; 2], GraphError>; fn parents(&self, rev: Revision) -> Result<[Revision; 2], GraphError>;
} }
#[derive(Clone, Debug, PartialEq)] #[derive(Clone, Debug, PartialEq)]
pub enum GraphError { pub enum GraphError {
ParentOutOfRange(Revision), ParentOutOfRange(Revision),
WorkingDirectoryUnsupported, WorkingDirectoryUnsupported,
} }
/// The Mercurial Revlog Index
///
/// This is currently limited to the minimal interface that is needed for
/// the [`nodemap`](nodemap/index.html) module
pub trait RevlogIndex {
/// Total number of Revisions referenced in this index
fn len(&self) -> usize;
/// Return a reference to the Node or `None` if rev is out of bounds
///
/// `NULL_REVISION` is not considered to be out of bounds.
fn node(&self, rev: Revision) -> Option<&Node>;
}