Mercurial > hg
view rust/hg-core/src/requirements.rs @ 46462:d03b0601e0eb
rhg: initial support for shared repositories
Differential Revision: https://phab.mercurial-scm.org/D9941
author | Simon Sapin <simon.sapin@octobus.net> |
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date | Thu, 14 Jan 2021 13:04:12 +0100 |
parents | 43d63979a75e |
children | 95b276283b67 |
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use crate::errors::{HgError, HgResultExt}; use crate::repo::{Repo, Vfs}; use std::collections::HashSet; fn parse(bytes: &[u8]) -> Result<HashSet<String>, HgError> { // The Python code reading this file uses `str.splitlines` // which looks for a number of line separators (even including a couple of // non-ASCII ones), but Python code writing it always uses `\n`. let lines = bytes.split(|&byte| byte == b'\n'); lines .filter(|line| !line.is_empty()) .map(|line| { // Python uses Unicode `str.isalnum` but feature names are all // ASCII if line[0].is_ascii_alphanumeric() && line.is_ascii() { Ok(String::from_utf8(line.into()).unwrap()) } else { Err(HgError::corrupted("parse error in 'requires' file")) } }) .collect() } pub(crate) fn load_if_exists(hg_vfs: Vfs) -> Result<HashSet<String>, HgError> { if let Some(bytes) = hg_vfs.read("requires").io_not_found_as_none()? { parse(&bytes) } else { // Treat a missing file the same as an empty file. // From `mercurial/localrepo.py`: // > requires file contains a newline-delimited list of // > features/capabilities the opener (us) must have in order to use // > the repository. This file was introduced in Mercurial 0.9.2, // > which means very old repositories may not have one. We assume // > a missing file translates to no requirements. Ok(HashSet::new()) } } pub(crate) fn check(repo: &Repo) -> Result<(), HgError> { for feature in repo.requirements() { if !SUPPORTED.contains(&feature.as_str()) { // TODO: collect and all unknown features and include them in the // error message? return Err(HgError::UnsupportedFeature(format!( "repository requires feature unknown to this Mercurial: {}", feature ))); } } Ok(()) } // TODO: set this to actually-supported features const SUPPORTED: &[&str] = &[ "dotencode", "fncache", "generaldelta", "revlogv1", SHARED_REQUIREMENT, SPARSEREVLOG_REQUIREMENT, RELATIVE_SHARED_REQUIREMENT, "store", // As of this writing everything rhg does is read-only. // When it starts writing to the repository, it’ll need to either keep the // persistent nodemap up to date or remove this entry: "persistent-nodemap", ]; // Copied from mercurial/requirements.py: /// When narrowing is finalized and no longer subject to format changes, /// we should move this to just "narrow" or similar. #[allow(unused)] pub(crate) const NARROW_REQUIREMENT: &str = "narrowhg-experimental"; /// Enables sparse working directory usage #[allow(unused)] pub(crate) const SPARSE_REQUIREMENT: &str = "exp-sparse"; /// Enables the internal phase which is used to hide changesets instead /// of stripping them #[allow(unused)] pub(crate) const INTERNAL_PHASE_REQUIREMENT: &str = "internal-phase"; /// Stores manifest in Tree structure #[allow(unused)] pub(crate) const TREEMANIFEST_REQUIREMENT: &str = "treemanifest"; /// Increment the sub-version when the revlog v2 format changes to lock out old /// clients. #[allow(unused)] pub(crate) const REVLOGV2_REQUIREMENT: &str = "exp-revlogv2.1"; /// A repository with the sparserevlog feature will have delta chains that /// can spread over a larger span. Sparse reading cuts these large spans into /// pieces, so that each piece isn't too big. /// Without the sparserevlog capability, reading from the repository could use /// huge amounts of memory, because the whole span would be read at once, /// including all the intermediate revisions that aren't pertinent for the /// chain. This is why once a repository has enabled sparse-read, it becomes /// required. #[allow(unused)] pub(crate) const SPARSEREVLOG_REQUIREMENT: &str = "sparserevlog"; /// A repository with the sidedataflag requirement will allow to store extra /// information for revision without altering their original hashes. #[allow(unused)] pub(crate) const SIDEDATA_REQUIREMENT: &str = "exp-sidedata-flag"; /// A repository with the the copies-sidedata-changeset requirement will store /// copies related information in changeset's sidedata. #[allow(unused)] pub(crate) const COPIESSDC_REQUIREMENT: &str = "exp-copies-sidedata-changeset"; /// The repository use persistent nodemap for the changelog and the manifest. #[allow(unused)] pub(crate) const NODEMAP_REQUIREMENT: &str = "persistent-nodemap"; /// Denotes that the current repository is a share #[allow(unused)] pub(crate) const SHARED_REQUIREMENT: &str = "shared"; /// Denotes that current repository is a share and the shared source path is /// relative to the current repository root path #[allow(unused)] pub(crate) const RELATIVE_SHARED_REQUIREMENT: &str = "relshared"; /// A repository with share implemented safely. The repository has different /// store and working copy requirements i.e. both `.hg/requires` and /// `.hg/store/requires` are present. #[allow(unused)] pub(crate) const SHARESAFE_REQUIREMENT: &str = "exp-sharesafe";