diff --git a/rust/hg-core/src/revlog/changelog.rs b/rust/hg-core/src/revlog/changelog.rs --- a/rust/hg-core/src/revlog/changelog.rs +++ b/rust/hg-core/src/revlog/changelog.rs @@ -1,6 +1,6 @@ use crate::errors::HgError; -use crate::revlog::Revision; use crate::revlog::{Node, NodePrefix}; +use crate::revlog::{Revision, NULL_REVISION}; use crate::revlog::{Revlog, RevlogEntry, RevlogError}; use crate::utils::hg_path::HgPath; use crate::vfs::Vfs; @@ -32,30 +32,29 @@ impl Changelog { self.data_for_rev(rev) } - /// Return the `RevlogEntry` for the given revision number. + /// Return the [`ChangelogEntry`] for the given revision number. pub fn entry_for_rev( &self, rev: Revision, - ) -> Result { - self.revlog.get_entry(rev) + ) -> Result { + let revlog_entry = self.revlog.get_entry(rev)?; + Ok(ChangelogEntry { revlog_entry }) } /// Return the [`ChangelogRevisionData`] for the given revision number. + /// + /// This is a useful shortcut in case the caller does not need the + /// generic revlog information (parents, hashes etc). Otherwise + /// consider taking a [`ChangelogEntry`] with + /// [entry_for_rev](`Self::entry_for_rev`) and doing everything from there. pub fn data_for_rev( &self, rev: Revision, ) -> Result { - let bytes = self.revlog.get_rev_data(rev)?; - if bytes.is_empty() { - Ok(ChangelogRevisionData::null()) - } else { - Ok(ChangelogRevisionData::new(bytes).map_err(|err| { - RevlogError::Other(HgError::CorruptedRepository(format!( - "Invalid changelog data for revision {}: {:?}", - rev, err - ))) - })?) + if rev == NULL_REVISION { + return Ok(ChangelogRevisionData::null()); } + self.entry_for_rev(rev)?.data() } pub fn node_from_rev(&self, rev: Revision) -> Option<&Node> { @@ -70,6 +69,45 @@ impl Changelog { } } +/// A specialized `RevlogEntry` for `changelog` data format +/// +/// This is a `RevlogEntry` with the added semantics that the associated +/// data should meet the requirements for `changelog`, materialized by +/// the fact that `data()` constructs a `ChangelogRevisionData`. +/// In case that promise would be broken, the `data` method returns an error. +#[derive(Clone)] +pub struct ChangelogEntry<'changelog> { + /// Same data, as a generic `RevlogEntry`. + pub(crate) revlog_entry: RevlogEntry<'changelog>, +} + +impl<'changelog> ChangelogEntry<'changelog> { + pub fn data<'a>( + &'a self, + ) -> Result, RevlogError> { + let bytes = self.revlog_entry.data()?; + if bytes.is_empty() { + Ok(ChangelogRevisionData::null()) + } else { + Ok(ChangelogRevisionData::new(bytes).map_err(|err| { + RevlogError::Other(HgError::CorruptedRepository(format!( + "Invalid changelog data for revision {}: {:?}", + self.revlog_entry.revision(), + err + ))) + })?) + } + } + + /// Obtain a reference to the underlying `RevlogEntry`. + /// + /// This allows the caller to access the information that is common + /// to all revlog entries: revision number, node id, parent revisions etc. + pub fn as_revlog_entry(&self) -> &RevlogEntry { + &self.revlog_entry + } +} + /// `Changelog` entry which knows how to interpret the `changelog` data bytes. #[derive(PartialEq)] pub struct ChangelogRevisionData<'changelog> {