D9941: rhg: initial support for shared repositories
SimonSapin
phabricator at mercurial-scm.org
Mon Feb 1 18:41:21 UTC 2021
SimonSapin created this revision.
Herald added a reviewer: hg-reviewers.
Herald added a subscriber: mercurial-patches.
REPOSITORY
rHG Mercurial
BRANCH
default
REVISION DETAIL
https://phab.mercurial-scm.org/D9941
AFFECTED FILES
rust/hg-core/src/errors.rs
rust/hg-core/src/repo.rs
rust/hg-core/src/requirements.rs
rust/rhg/src/commands/debugrequirements.rs
tests/test-rhg.t
CHANGE DETAILS
diff --git a/tests/test-rhg.t b/tests/test-rhg.t
--- a/tests/test-rhg.t
+++ b/tests/test-rhg.t
@@ -218,9 +218,9 @@
$ cd repo2
$ rhg files
- [252]
+ a
$ rhg cat -r 0 a
- [252]
+ a
Same with relative sharing
@@ -231,9 +231,9 @@
$ cd repo3
$ rhg files
- [252]
+ a
$ rhg cat -r 0 a
- [252]
+ a
Same with share-safe
diff --git a/rust/rhg/src/commands/debugrequirements.rs b/rust/rhg/src/commands/debugrequirements.rs
--- a/rust/rhg/src/commands/debugrequirements.rs
+++ b/rust/rhg/src/commands/debugrequirements.rs
@@ -2,7 +2,6 @@
use crate::error::CommandError;
use crate::ui::Ui;
use hg::repo::Repo;
-use hg::requirements;
pub const HELP_TEXT: &str = "
Print the current repo requirements.
@@ -20,8 +19,10 @@
fn run(&self, ui: &Ui) -> Result<(), CommandError> {
let repo = Repo::find()?;
let mut output = String::new();
- for req in requirements::load(&repo)? {
- output.push_str(&req);
+ let mut requirements: Vec<_> = repo.requirements().iter().collect();
+ requirements.sort();
+ for req in requirements {
+ output.push_str(req);
output.push('\n');
}
ui.write_stdout(output.as_bytes())?;
diff --git a/rust/hg-core/src/requirements.rs b/rust/hg-core/src/requirements.rs
--- a/rust/hg-core/src/requirements.rs
+++ b/rust/hg-core/src/requirements.rs
@@ -1,7 +1,8 @@
use crate::errors::{HgError, HgResultExt};
-use crate::repo::Repo;
+use crate::repo::{Repo, Vfs};
+use std::collections::HashSet;
-fn parse(bytes: &[u8]) -> Result<Vec<String>, HgError> {
+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`.
@@ -21,10 +22,8 @@
.collect()
}
-pub fn load(repo: &Repo) -> Result<Vec<String>, HgError> {
- if let Some(bytes) =
- repo.hg_vfs().read("requires").io_not_found_as_none()?
- {
+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.
@@ -34,13 +33,13 @@
// > 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(Vec::new())
+ Ok(HashSet::new())
}
}
-pub fn check(repo: &Repo) -> Result<(), HgError> {
- for feature in load(repo)? {
- if !SUPPORTED.contains(&&*feature) {
+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!(
@@ -58,10 +57,77 @@
"fncache",
"generaldelta",
"revlogv1",
- "sparserevlog",
+ 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, itâll 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";
diff --git a/rust/hg-core/src/repo.rs b/rust/hg-core/src/repo.rs
--- a/rust/hg-core/src/repo.rs
+++ b/rust/hg-core/src/repo.rs
@@ -1,6 +1,8 @@
use crate::errors::{HgError, IoResultExt};
use crate::requirements;
+use crate::utils::files::get_path_from_bytes;
use memmap::{Mmap, MmapOptions};
+use std::collections::HashSet;
use std::path::{Path, PathBuf};
/// A repository on disk
@@ -8,6 +10,7 @@
working_directory: PathBuf,
dot_hg: PathBuf,
store: PathBuf,
+ requirements: HashSet<String>,
}
#[derive(Debug, derive_more::From)]
@@ -32,15 +35,8 @@
let current_directory = crate::utils::current_dir()?;
// ancestors() is inclusive: it first yields `current_directory` as-is.
for ancestor in current_directory.ancestors() {
- let dot_hg = ancestor.join(".hg");
- if dot_hg.is_dir() {
- let repo = Self {
- store: dot_hg.join("store"),
- dot_hg,
- working_directory: ancestor.to_owned(),
- };
- requirements::check(&repo)?;
- return Ok(repo);
+ if ancestor.join(".hg").is_dir() {
+ return Ok(Self::new_at_path(ancestor.to_owned())?);
}
}
Err(RepoFindError::NotFoundInCurrentDirectoryOrAncestors {
@@ -48,10 +44,54 @@
})
}
+ /// To be called after checking that `.hg` is a sub-directory
+ fn new_at_path(working_directory: PathBuf) -> Result<Self, HgError> {
+ let dot_hg = working_directory.join(".hg");
+ let hg_vfs = Vfs { base: &dot_hg };
+ let reqs = requirements::load_if_exists(hg_vfs)?;
+ let relative =
+ reqs.contains(requirements::RELATIVE_SHARED_REQUIREMENT);
+ let shared =
+ reqs.contains(requirements::SHARED_REQUIREMENT) || relative;
+ let store_path;
+ if !shared {
+ store_path = dot_hg.join("store");
+ } else {
+ let bytes = hg_vfs.read("sharedpath")?;
+ let mut shared_path = get_path_from_bytes(&bytes).to_owned();
+ if relative {
+ shared_path = dot_hg.join(shared_path)
+ }
+ if !shared_path.is_dir() {
+ return Err(HgError::corrupted(format!(
+ ".hg/sharedpath points to nonexistent directory {}",
+ shared_path.display()
+ )));
+ }
+
+ store_path = shared_path.join("store");
+ }
+
+ let repo = Self {
+ requirements: reqs,
+ working_directory,
+ store: store_path,
+ dot_hg,
+ };
+
+ requirements::check(&repo)?;
+
+ Ok(repo)
+ }
+
pub fn working_directory_path(&self) -> &Path {
&self.working_directory
}
+ pub fn requirements(&self) -> &HashSet<String> {
+ &self.requirements
+ }
+
/// For accessing repository files (in `.hg`), except for the store
/// (`.hg/store`).
pub(crate) fn hg_vfs(&self) -> Vfs<'_> {
diff --git a/rust/hg-core/src/errors.rs b/rust/hg-core/src/errors.rs
--- a/rust/hg-core/src/errors.rs
+++ b/rust/hg-core/src/errors.rs
@@ -40,6 +40,10 @@
// https://doc.rust-lang.org/std/backtrace/struct.Backtrace.html
HgError::CorruptedRepository(explanation.into())
}
+
+ pub fn unsupported(explanation: impl Into<String>) -> Self {
+ HgError::UnsupportedFeature(explanation.into())
+ }
}
// TODO: use `DisplayBytes` instead to show non-Unicode filenames losslessly?
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