Mercurial > hg
view rust/hg-core/src/dirstate_tree/status.rs @ 48260:269ff8978086
dirstate: store mtimes with nanosecond precision in memory
Keep integer seconds since the Unix epoch,
together with integer nanoseconds in the `0 <= n < 1e9` range.
For now, nanoseconds are still always zero.
This commit is about data structure changes.
Differential Revision: https://phab.mercurial-scm.org/D11684
author | Simon Sapin <simon.sapin@octobus.net> |
---|---|
date | Mon, 18 Oct 2021 11:23:07 +0200 |
parents | f45d35950db6 |
children | 83d0bd45b662 |
line wrap: on
line source
use crate::dirstate::entry::TruncatedTimestamp; use crate::dirstate::status::IgnoreFnType; use crate::dirstate_tree::dirstate_map::BorrowedPath; use crate::dirstate_tree::dirstate_map::ChildNodesRef; use crate::dirstate_tree::dirstate_map::DirstateMap; use crate::dirstate_tree::dirstate_map::NodeData; use crate::dirstate_tree::dirstate_map::NodeRef; use crate::dirstate_tree::on_disk::DirstateV2ParseError; use crate::matchers::get_ignore_function; use crate::matchers::Matcher; use crate::utils::files::get_bytes_from_os_string; use crate::utils::files::get_path_from_bytes; use crate::utils::hg_path::HgPath; use crate::BadMatch; use crate::DirstateStatus; use crate::EntryState; use crate::HgPathBuf; use crate::PatternFileWarning; use crate::StatusError; use crate::StatusOptions; use micro_timer::timed; use rayon::prelude::*; use sha1::{Digest, Sha1}; use std::borrow::Cow; use std::io; use std::path::Path; use std::path::PathBuf; use std::sync::Mutex; use std::time::SystemTime; /// Returns the status of the working directory compared to its parent /// changeset. /// /// This algorithm is based on traversing the filesystem tree (`fs` in function /// and variable names) and dirstate tree at the same time. The core of this /// traversal is the recursive `traverse_fs_directory_and_dirstate` function /// and its use of `itertools::merge_join_by`. When reaching a path that only /// exists in one of the two trees, depending on information requested by /// `options` we may need to traverse the remaining subtree. #[timed] pub fn status<'tree, 'on_disk: 'tree>( dmap: &'tree mut DirstateMap<'on_disk>, matcher: &(dyn Matcher + Sync), root_dir: PathBuf, ignore_files: Vec<PathBuf>, options: StatusOptions, ) -> Result<(DirstateStatus<'on_disk>, Vec<PatternFileWarning>), StatusError> { let (ignore_fn, warnings, patterns_changed): (IgnoreFnType, _, _) = if options.list_ignored || options.list_unknown { let mut hasher = Sha1::new(); let (ignore_fn, warnings) = get_ignore_function( ignore_files, &root_dir, &mut |pattern_bytes| hasher.update(pattern_bytes), )?; let new_hash = *hasher.finalize().as_ref(); let changed = new_hash != dmap.ignore_patterns_hash; dmap.ignore_patterns_hash = new_hash; (ignore_fn, warnings, Some(changed)) } else { (Box::new(|&_| true), vec![], None) }; let common = StatusCommon { dmap, options, matcher, ignore_fn, outcome: Default::default(), ignore_patterns_have_changed: patterns_changed, new_cachable_directories: Default::default(), outated_cached_directories: Default::default(), filesystem_time_at_status_start: filesystem_now(&root_dir).ok(), }; let is_at_repo_root = true; let hg_path = &BorrowedPath::OnDisk(HgPath::new("")); let has_ignored_ancestor = false; let root_cached_mtime = None; let root_dir_metadata = None; // If the path we have for the repository root is a symlink, do follow it. // (As opposed to symlinks within the working directory which are not // followed, using `std::fs::symlink_metadata`.) common.traverse_fs_directory_and_dirstate( has_ignored_ancestor, dmap.root.as_ref(), hg_path, &root_dir, root_dir_metadata, root_cached_mtime, is_at_repo_root, )?; let mut outcome = common.outcome.into_inner().unwrap(); let new_cachable = common.new_cachable_directories.into_inner().unwrap(); let outdated = common.outated_cached_directories.into_inner().unwrap(); outcome.dirty = common.ignore_patterns_have_changed == Some(true) || !outdated.is_empty() || !new_cachable.is_empty(); // Remove outdated mtimes before adding new mtimes, in case a given // directory is both for path in &outdated { let node = dmap.get_or_insert(path)?; if let NodeData::CachedDirectory { .. } = &node.data { node.data = NodeData::None } } for (path, mtime) in &new_cachable { let node = dmap.get_or_insert(path)?; match &node.data { NodeData::Entry(_) => {} // Don’t overwrite an entry NodeData::CachedDirectory { .. } | NodeData::None => { node.data = NodeData::CachedDirectory { mtime: *mtime } } } } Ok((outcome, warnings)) } /// Bag of random things needed by various parts of the algorithm. Reduces the /// number of parameters passed to functions. struct StatusCommon<'a, 'tree, 'on_disk: 'tree> { dmap: &'tree DirstateMap<'on_disk>, options: StatusOptions, matcher: &'a (dyn Matcher + Sync), ignore_fn: IgnoreFnType<'a>, outcome: Mutex<DirstateStatus<'on_disk>>, new_cachable_directories: Mutex<Vec<(Cow<'on_disk, HgPath>, TruncatedTimestamp)>>, outated_cached_directories: Mutex<Vec<Cow<'on_disk, HgPath>>>, /// Whether ignore files like `.hgignore` have changed since the previous /// time a `status()` call wrote their hash to the dirstate. `None` means /// we don’t know as this run doesn’t list either ignored or uknown files /// and therefore isn’t reading `.hgignore`. ignore_patterns_have_changed: Option<bool>, /// The current time at the start of the `status()` algorithm, as measured /// and possibly truncated by the filesystem. filesystem_time_at_status_start: Option<SystemTime>, } impl<'a, 'tree, 'on_disk> StatusCommon<'a, 'tree, 'on_disk> { fn read_dir( &self, hg_path: &HgPath, fs_path: &Path, is_at_repo_root: bool, ) -> Result<Vec<DirEntry>, ()> { DirEntry::read_dir(fs_path, is_at_repo_root) .map_err(|error| self.io_error(error, hg_path)) } fn io_error(&self, error: std::io::Error, hg_path: &HgPath) { let errno = error.raw_os_error().expect("expected real OS error"); self.outcome .lock() .unwrap() .bad .push((hg_path.to_owned().into(), BadMatch::OsError(errno))) } fn check_for_outdated_directory_cache( &self, dirstate_node: &NodeRef<'tree, 'on_disk>, ) -> Result<(), DirstateV2ParseError> { if self.ignore_patterns_have_changed == Some(true) && dirstate_node.cached_directory_mtime()?.is_some() { self.outated_cached_directories.lock().unwrap().push( dirstate_node .full_path_borrowed(self.dmap.on_disk)? .detach_from_tree(), ) } Ok(()) } /// If this returns true, we can get accurate results by only using /// `symlink_metadata` for child nodes that exist in the dirstate and don’t /// need to call `read_dir`. fn can_skip_fs_readdir( &self, directory_metadata: Option<&std::fs::Metadata>, cached_directory_mtime: Option<TruncatedTimestamp>, ) -> bool { if !self.options.list_unknown && !self.options.list_ignored { // All states that we care about listing have corresponding // dirstate entries. // This happens for example with `hg status -mard`. return true; } if !self.options.list_ignored && self.ignore_patterns_have_changed == Some(false) { if let Some(cached_mtime) = cached_directory_mtime { // The dirstate contains a cached mtime for this directory, set // by a previous run of the `status` algorithm which found this // directory eligible for `read_dir` caching. if let Some(meta) = directory_metadata { if cached_mtime .likely_equal_to_mtime_of(meta) .unwrap_or(false) { // The mtime of that directory has not changed // since then, which means that the results of // `read_dir` should also be unchanged. return true; } } } } false } /// Returns whether all child entries of the filesystem directory have a /// corresponding dirstate node or are ignored. fn traverse_fs_directory_and_dirstate( &self, has_ignored_ancestor: bool, dirstate_nodes: ChildNodesRef<'tree, 'on_disk>, directory_hg_path: &BorrowedPath<'tree, 'on_disk>, directory_fs_path: &Path, directory_metadata: Option<&std::fs::Metadata>, cached_directory_mtime: Option<TruncatedTimestamp>, is_at_repo_root: bool, ) -> Result<bool, DirstateV2ParseError> { if self.can_skip_fs_readdir(directory_metadata, cached_directory_mtime) { dirstate_nodes .par_iter() .map(|dirstate_node| { let fs_path = directory_fs_path.join(get_path_from_bytes( dirstate_node.base_name(self.dmap.on_disk)?.as_bytes(), )); match std::fs::symlink_metadata(&fs_path) { Ok(fs_metadata) => self.traverse_fs_and_dirstate( &fs_path, &fs_metadata, dirstate_node, has_ignored_ancestor, ), Err(e) if e.kind() == std::io::ErrorKind::NotFound => { self.traverse_dirstate_only(dirstate_node) } Err(error) => { let hg_path = dirstate_node.full_path(self.dmap.on_disk)?; Ok(self.io_error(error, hg_path)) } } }) .collect::<Result<_, _>>()?; // We don’t know, so conservatively say this isn’t the case let children_all_have_dirstate_node_or_are_ignored = false; return Ok(children_all_have_dirstate_node_or_are_ignored); } let mut fs_entries = if let Ok(entries) = self.read_dir( directory_hg_path, directory_fs_path, is_at_repo_root, ) { entries } else { // Treat an unreadable directory (typically because of insufficient // permissions) like an empty directory. `self.read_dir` has // already called `self.io_error` so a warning will be emitted. Vec::new() }; // `merge_join_by` requires both its input iterators to be sorted: let dirstate_nodes = dirstate_nodes.sorted(); // `sort_unstable_by_key` doesn’t allow keys borrowing from the value: // https://github.com/rust-lang/rust/issues/34162 fs_entries.sort_unstable_by(|e1, e2| e1.base_name.cmp(&e2.base_name)); // Propagate here any error that would happen inside the comparison // callback below for dirstate_node in &dirstate_nodes { dirstate_node.base_name(self.dmap.on_disk)?; } itertools::merge_join_by( dirstate_nodes, &fs_entries, |dirstate_node, fs_entry| { // This `unwrap` never panics because we already propagated // those errors above dirstate_node .base_name(self.dmap.on_disk) .unwrap() .cmp(&fs_entry.base_name) }, ) .par_bridge() .map(|pair| { use itertools::EitherOrBoth::*; let has_dirstate_node_or_is_ignored; match pair { Both(dirstate_node, fs_entry) => { self.traverse_fs_and_dirstate( &fs_entry.full_path, &fs_entry.metadata, dirstate_node, has_ignored_ancestor, )?; has_dirstate_node_or_is_ignored = true } Left(dirstate_node) => { self.traverse_dirstate_only(dirstate_node)?; has_dirstate_node_or_is_ignored = true; } Right(fs_entry) => { has_dirstate_node_or_is_ignored = self.traverse_fs_only( has_ignored_ancestor, directory_hg_path, fs_entry, ) } } Ok(has_dirstate_node_or_is_ignored) }) .try_reduce(|| true, |a, b| Ok(a && b)) } fn traverse_fs_and_dirstate( &self, fs_path: &Path, fs_metadata: &std::fs::Metadata, dirstate_node: NodeRef<'tree, 'on_disk>, has_ignored_ancestor: bool, ) -> Result<(), DirstateV2ParseError> { self.check_for_outdated_directory_cache(&dirstate_node)?; let hg_path = &dirstate_node.full_path_borrowed(self.dmap.on_disk)?; let file_type = fs_metadata.file_type(); let file_or_symlink = file_type.is_file() || file_type.is_symlink(); if !file_or_symlink { // If we previously had a file here, it was removed (with // `hg rm` or similar) or deleted before it could be // replaced by a directory or something else. self.mark_removed_or_deleted_if_file( &hg_path, dirstate_node.state()?, ); } if file_type.is_dir() { if self.options.collect_traversed_dirs { self.outcome .lock() .unwrap() .traversed .push(hg_path.detach_from_tree()) } let is_ignored = has_ignored_ancestor || (self.ignore_fn)(hg_path); let is_at_repo_root = false; let children_all_have_dirstate_node_or_are_ignored = self .traverse_fs_directory_and_dirstate( is_ignored, dirstate_node.children(self.dmap.on_disk)?, hg_path, fs_path, Some(fs_metadata), dirstate_node.cached_directory_mtime()?, is_at_repo_root, )?; self.maybe_save_directory_mtime( children_all_have_dirstate_node_or_are_ignored, fs_metadata, dirstate_node, )? } else { if file_or_symlink && self.matcher.matches(hg_path) { if let Some(state) = dirstate_node.state()? { match state { EntryState::Added => self .outcome .lock() .unwrap() .added .push(hg_path.detach_from_tree()), EntryState::Removed => self .outcome .lock() .unwrap() .removed .push(hg_path.detach_from_tree()), EntryState::Merged => self .outcome .lock() .unwrap() .modified .push(hg_path.detach_from_tree()), EntryState::Normal => self .handle_normal_file(&dirstate_node, fs_metadata)?, } } else { // `node.entry.is_none()` indicates a "directory" // node, but the filesystem has a file self.mark_unknown_or_ignored( has_ignored_ancestor, hg_path, ); } } for child_node in dirstate_node.children(self.dmap.on_disk)?.iter() { self.traverse_dirstate_only(child_node)? } } Ok(()) } fn maybe_save_directory_mtime( &self, children_all_have_dirstate_node_or_are_ignored: bool, directory_metadata: &std::fs::Metadata, dirstate_node: NodeRef<'tree, 'on_disk>, ) -> Result<(), DirstateV2ParseError> { if children_all_have_dirstate_node_or_are_ignored { // All filesystem directory entries from `read_dir` have a // corresponding node in the dirstate, so we can reconstitute the // names of those entries without calling `read_dir` again. if let (Some(status_start), Ok(directory_mtime)) = ( &self.filesystem_time_at_status_start, directory_metadata.modified(), ) { // Although the Rust standard library’s `SystemTime` type // has nanosecond precision, the times reported for a // directory’s (or file’s) modified time may have lower // resolution based on the filesystem (for example ext3 // only stores integer seconds), kernel (see // https://stackoverflow.com/a/14393315/1162888), etc. if &directory_mtime >= status_start { // The directory was modified too recently, don’t cache its // `read_dir` results. // // A timeline like this is possible: // // 1. A change to this directory (direct child was // added or removed) cause its mtime to be set // (possibly truncated) to `directory_mtime` // 2. This `status` algorithm calls `read_dir` // 3. An other change is made to the same directory is // made so that calling `read_dir` agin would give // different results, but soon enough after 1. that // the mtime stays the same // // On a system where the time resolution poor, this // scenario is not unlikely if all three steps are caused // by the same script. } else { // We’ve observed (through `status_start`) that time has // “progressed” since `directory_mtime`, so any further // change to this directory is extremely likely to cause a // different mtime. // // Having the same mtime again is not entirely impossible // since the system clock is not monotonous. It could jump // backward to some point before `directory_mtime`, then a // directory change could potentially happen during exactly // the wrong tick. // // We deem this scenario (unlike the previous one) to be // unlikely enough in practice. let truncated = TruncatedTimestamp::from(directory_mtime); let is_up_to_date = if let Some(cached) = dirstate_node.cached_directory_mtime()? { cached.likely_equal(truncated) } else { false }; if !is_up_to_date { let hg_path = dirstate_node .full_path_borrowed(self.dmap.on_disk)? .detach_from_tree(); self.new_cachable_directories .lock() .unwrap() .push((hg_path, truncated)) } } } } Ok(()) } /// A file with `EntryState::Normal` in the dirstate was found in the /// filesystem fn handle_normal_file( &self, dirstate_node: &NodeRef<'tree, 'on_disk>, fs_metadata: &std::fs::Metadata, ) -> Result<(), DirstateV2ParseError> { // Keep the low 31 bits fn truncate_u64(value: u64) -> i32 { (value & 0x7FFF_FFFF) as i32 } let entry = dirstate_node .entry()? .expect("handle_normal_file called with entry-less node"); let hg_path = &dirstate_node.full_path_borrowed(self.dmap.on_disk)?; let mode_changed = || self.options.check_exec && entry.mode_changed(fs_metadata); let size = entry.size(); let size_changed = size != truncate_u64(fs_metadata.len()); if size >= 0 && size_changed && fs_metadata.file_type().is_symlink() { // issue6456: Size returned may be longer due to encryption // on EXT-4 fscrypt. TODO maybe only do it on EXT4? self.outcome .lock() .unwrap() .unsure .push(hg_path.detach_from_tree()) } else if dirstate_node.has_copy_source() || entry.is_from_other_parent() || (size >= 0 && (size_changed || mode_changed())) { self.outcome .lock() .unwrap() .modified .push(hg_path.detach_from_tree()) } else { let mtime_looks_clean; if let Some(dirstate_mtime) = entry.truncated_mtime() { let fs_mtime = TruncatedTimestamp::for_mtime_of(fs_metadata) .expect("OS/libc does not support mtime?") // For now don’t use sub-second precision for file mtimes .to_integer_second(); mtime_looks_clean = fs_mtime.likely_equal(dirstate_mtime) && !fs_mtime.likely_equal(self.options.last_normal_time) } else { // No mtime in the dirstate entry mtime_looks_clean = false }; if !mtime_looks_clean { self.outcome .lock() .unwrap() .unsure .push(hg_path.detach_from_tree()) } else if self.options.list_clean { self.outcome .lock() .unwrap() .clean .push(hg_path.detach_from_tree()) } } Ok(()) } /// A node in the dirstate tree has no corresponding filesystem entry fn traverse_dirstate_only( &self, dirstate_node: NodeRef<'tree, 'on_disk>, ) -> Result<(), DirstateV2ParseError> { self.check_for_outdated_directory_cache(&dirstate_node)?; self.mark_removed_or_deleted_if_file( &dirstate_node.full_path_borrowed(self.dmap.on_disk)?, dirstate_node.state()?, ); dirstate_node .children(self.dmap.on_disk)? .par_iter() .map(|child_node| self.traverse_dirstate_only(child_node)) .collect() } /// A node in the dirstate tree has no corresponding *file* on the /// filesystem /// /// Does nothing on a "directory" node fn mark_removed_or_deleted_if_file( &self, hg_path: &BorrowedPath<'tree, 'on_disk>, dirstate_node_state: Option<EntryState>, ) { if let Some(state) = dirstate_node_state { if self.matcher.matches(hg_path) { if let EntryState::Removed = state { self.outcome .lock() .unwrap() .removed .push(hg_path.detach_from_tree()) } else { self.outcome .lock() .unwrap() .deleted .push(hg_path.detach_from_tree()) } } } } /// Something in the filesystem has no corresponding dirstate node /// /// Returns whether that path is ignored fn traverse_fs_only( &self, has_ignored_ancestor: bool, directory_hg_path: &HgPath, fs_entry: &DirEntry, ) -> bool { let hg_path = directory_hg_path.join(&fs_entry.base_name); let file_type = fs_entry.metadata.file_type(); let file_or_symlink = file_type.is_file() || file_type.is_symlink(); if file_type.is_dir() { let is_ignored = has_ignored_ancestor || (self.ignore_fn)(&hg_path); let traverse_children = if is_ignored { // Descendants of an ignored directory are all ignored self.options.list_ignored } else { // Descendants of an unknown directory may be either unknown or // ignored self.options.list_unknown || self.options.list_ignored }; if traverse_children { let is_at_repo_root = false; if let Ok(children_fs_entries) = self.read_dir( &hg_path, &fs_entry.full_path, is_at_repo_root, ) { children_fs_entries.par_iter().for_each(|child_fs_entry| { self.traverse_fs_only( is_ignored, &hg_path, child_fs_entry, ); }) } } if self.options.collect_traversed_dirs { self.outcome.lock().unwrap().traversed.push(hg_path.into()) } is_ignored } else { if file_or_symlink { if self.matcher.matches(&hg_path) { self.mark_unknown_or_ignored( has_ignored_ancestor, &BorrowedPath::InMemory(&hg_path), ) } else { // We haven’t computed whether this path is ignored. It // might not be, and a future run of status might have a // different matcher that matches it. So treat it as not // ignored. That is, inhibit readdir caching of the parent // directory. false } } else { // This is neither a directory, a plain file, or a symlink. // Treat it like an ignored file. true } } } /// Returns whether that path is ignored fn mark_unknown_or_ignored( &self, has_ignored_ancestor: bool, hg_path: &BorrowedPath<'_, 'on_disk>, ) -> bool { let is_ignored = has_ignored_ancestor || (self.ignore_fn)(&hg_path); if is_ignored { if self.options.list_ignored { self.outcome .lock() .unwrap() .ignored .push(hg_path.detach_from_tree()) } } else { if self.options.list_unknown { self.outcome .lock() .unwrap() .unknown .push(hg_path.detach_from_tree()) } } is_ignored } } struct DirEntry { base_name: HgPathBuf, full_path: PathBuf, metadata: std::fs::Metadata, } impl DirEntry { /// Returns **unsorted** entries in the given directory, with name and /// metadata. /// /// If a `.hg` sub-directory is encountered: /// /// * At the repository root, ignore that sub-directory /// * Elsewhere, we’re listing the content of a sub-repo. Return an empty /// list instead. fn read_dir(path: &Path, is_at_repo_root: bool) -> io::Result<Vec<Self>> { let mut results = Vec::new(); for entry in path.read_dir()? { let entry = entry?; let metadata = entry.metadata()?; let name = get_bytes_from_os_string(entry.file_name()); // FIXME don't do this when cached if name == b".hg" { if is_at_repo_root { // Skip the repo’s own .hg (might be a symlink) continue; } else if metadata.is_dir() { // A .hg sub-directory at another location means a subrepo, // skip it entirely. return Ok(Vec::new()); } } results.push(DirEntry { base_name: name.into(), full_path: entry.path(), metadata, }) } Ok(results) } } /// Return the `mtime` of a temporary file newly-created in the `.hg` directory /// of the give repository. /// /// This is similar to `SystemTime::now()`, with the result truncated to the /// same time resolution as other files’ modification times. Using `.hg` /// instead of the system’s default temporary directory (such as `/tmp`) makes /// it more likely the temporary file is in the same disk partition as contents /// of the working directory, which can matter since different filesystems may /// store timestamps with different resolutions. /// /// This may fail, typically if we lack write permissions. In that case we /// should continue the `status()` algoritm anyway and consider the current /// date/time to be unknown. fn filesystem_now(repo_root: &Path) -> Result<SystemTime, io::Error> { tempfile::tempfile_in(repo_root.join(".hg"))? .metadata()? .modified() }