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rust: Add type annotation to fix inference on Rust Nightly...
rust: Add type annotation to fix inference on Rust Nightly When compiling with Rust Nightly, the im-rs crate silently makes use of the experimental language feature for trait impl specialization. This apperently changes public its APIs in subtle ways such that type inference of some user code can fail where it succeeds when specialization is disabled. This made Mercurial’s Rust unit tests have compilation errors on Nightly. I have not managed to find the exactl root cause, but I wrote down my findings so far at https://github.com/bodil/im-rs/issues/188 This adds type annotation to make unit tests rely less on type inference and work around the issue. Differential Revision: https://phab.mercurial-scm.org/D10742

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config.rs
481 lines | 15.9 KiB | application/rls-services+xml | RustLexer
// config.rs
//
// Copyright 2020
// Valentin Gatien-Baron,
// Raphaël Gomès <rgomes@octobus.net>
//
// This software may be used and distributed according to the terms of the
// GNU General Public License version 2 or any later version.
use super::layer;
use super::values;
use crate::config::layer::{
ConfigError, ConfigLayer, ConfigOrigin, ConfigValue,
};
use crate::utils::files::get_bytes_from_os_str;
use crate::utils::SliceExt;
use format_bytes::{write_bytes, DisplayBytes};
use std::collections::HashSet;
use std::env;
use std::fmt;
use std::path::{Path, PathBuf};
use std::str;
use crate::errors::{HgResultExt, IoResultExt};
/// Holds the config values for the current repository
/// TODO update this docstring once we support more sources
#[derive(Clone)]
pub struct Config {
layers: Vec<layer::ConfigLayer>,
}
impl DisplayBytes for Config {
fn display_bytes(
&self,
out: &mut dyn std::io::Write,
) -> std::io::Result<()> {
for (index, layer) in self.layers.iter().rev().enumerate() {
write_bytes!(
out,
b"==== Layer {} (trusted: {}) ====\n{}",
index,
if layer.trusted {
&b"yes"[..]
} else {
&b"no"[..]
},
layer
)?;
}
Ok(())
}
}
pub enum ConfigSource {
/// Absolute path to a config file
AbsPath(PathBuf),
/// Already parsed (from the CLI, env, Python resources, etc.)
Parsed(layer::ConfigLayer),
}
#[derive(Debug)]
pub struct ConfigValueParseError {
pub origin: ConfigOrigin,
pub line: Option<usize>,
pub section: Vec<u8>,
pub item: Vec<u8>,
pub value: Vec<u8>,
pub expected_type: &'static str,
}
impl fmt::Display for ConfigValueParseError {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
// TODO: add origin and line number information, here and in
// corresponding python code
write!(
f,
"config error: {}.{} is not a {} ('{}')",
String::from_utf8_lossy(&self.section),
String::from_utf8_lossy(&self.item),
self.expected_type,
String::from_utf8_lossy(&self.value)
)
}
}
impl Config {
/// Load system and user configuration from various files.
///
/// This is also affected by some environment variables.
pub fn load(
cli_config_args: impl IntoIterator<Item = impl AsRef<[u8]>>,
) -> Result<Self, ConfigError> {
let mut config = Self { layers: Vec::new() };
let opt_rc_path = env::var_os("HGRCPATH");
// HGRCPATH replaces system config
if opt_rc_path.is_none() {
config.add_system_config()?
}
config.add_for_environment_variable("EDITOR", b"ui", b"editor");
config.add_for_environment_variable("VISUAL", b"ui", b"editor");
config.add_for_environment_variable("PAGER", b"pager", b"pager");
// These are set by `run-tests.py --rhg` to enable fallback for the
// entire test suite. Alternatives would be setting configuration
// through `$HGRCPATH` but some tests override that, or changing the
// `hg` shell alias to include `--config` but that disrupts tests that
// print command lines and check expected output.
config.add_for_environment_variable(
"RHG_ON_UNSUPPORTED",
b"rhg",
b"on-unsupported",
);
config.add_for_environment_variable(
"RHG_FALLBACK_EXECUTABLE",
b"rhg",
b"fallback-executable",
);
// HGRCPATH replaces user config
if opt_rc_path.is_none() {
config.add_user_config()?
}
if let Some(rc_path) = &opt_rc_path {
for path in env::split_paths(rc_path) {
if !path.as_os_str().is_empty() {
if path.is_dir() {
config.add_trusted_dir(&path)?
} else {
config.add_trusted_file(&path)?
}
}
}
}
if let Some(layer) = ConfigLayer::parse_cli_args(cli_config_args)? {
config.layers.push(layer)
}
Ok(config)
}
fn add_trusted_dir(&mut self, path: &Path) -> Result<(), ConfigError> {
if let Some(entries) = std::fs::read_dir(path)
.when_reading_file(path)
.io_not_found_as_none()?
{
let mut file_paths = entries
.map(|result| {
result.when_reading_file(path).map(|entry| entry.path())
})
.collect::<Result<Vec<_>, _>>()?;
file_paths.sort();
for file_path in &file_paths {
if file_path.extension() == Some(std::ffi::OsStr::new("rc")) {
self.add_trusted_file(&file_path)?
}
}
}
Ok(())
}
fn add_trusted_file(&mut self, path: &Path) -> Result<(), ConfigError> {
if let Some(data) = std::fs::read(path)
.when_reading_file(path)
.io_not_found_as_none()?
{
self.layers.extend(ConfigLayer::parse(path, &data)?)
}
Ok(())
}
fn add_for_environment_variable(
&mut self,
var: &str,
section: &[u8],
key: &[u8],
) {
if let Some(value) = env::var_os(var) {
let origin = layer::ConfigOrigin::Environment(var.into());
let mut layer = ConfigLayer::new(origin);
layer.add(
section.to_owned(),
key.to_owned(),
get_bytes_from_os_str(value),
None,
);
self.layers.push(layer)
}
}
#[cfg(unix)] // TODO: other platforms
fn add_system_config(&mut self) -> Result<(), ConfigError> {
let mut add_for_prefix = |prefix: &Path| -> Result<(), ConfigError> {
let etc = prefix.join("etc").join("mercurial");
self.add_trusted_file(&etc.join("hgrc"))?;
self.add_trusted_dir(&etc.join("hgrc.d"))
};
let root = Path::new("/");
// TODO: use `std::env::args_os().next().unwrap()` a.k.a. argv[0]
// instead? TODO: can this be a relative path?
let hg = crate::utils::current_exe()?;
// TODO: this order (per-installation then per-system) matches
// `systemrcpath()` in `mercurial/scmposix.py`, but
// `mercurial/helptext/config.txt` suggests it should be reversed
if let Some(installation_prefix) = hg.parent().and_then(Path::parent) {
if installation_prefix != root {
add_for_prefix(&installation_prefix)?
}
}
add_for_prefix(root)?;
Ok(())
}
#[cfg(unix)] // TODO: other plateforms
fn add_user_config(&mut self) -> Result<(), ConfigError> {
let opt_home = home::home_dir();
if let Some(home) = &opt_home {
self.add_trusted_file(&home.join(".hgrc"))?
}
let darwin = cfg!(any(target_os = "macos", target_os = "ios"));
if !darwin {
if let Some(config_home) = env::var_os("XDG_CONFIG_HOME")
.map(PathBuf::from)
.or_else(|| opt_home.map(|home| home.join(".config")))
{
self.add_trusted_file(&config_home.join("hg").join("hgrc"))?
}
}
Ok(())
}
/// Loads in order, which means that the precedence is the same
/// as the order of `sources`.
pub fn load_from_explicit_sources(
sources: Vec<ConfigSource>,
) -> Result<Self, ConfigError> {
let mut layers = vec![];
for source in sources.into_iter() {
match source {
ConfigSource::Parsed(c) => layers.push(c),
ConfigSource::AbsPath(c) => {
// TODO check if it should be trusted
// mercurial/ui.py:427
let data = match std::fs::read(&c) {
Err(_) => continue, // same as the python code
Ok(data) => data,
};
layers.extend(ConfigLayer::parse(&c, &data)?)
}
}
}
Ok(Config { layers })
}
/// Loads the per-repository config into a new `Config` which is combined
/// with `self`.
pub(crate) fn combine_with_repo(
&self,
repo_config_files: &[PathBuf],
) -> Result<Self, ConfigError> {
let (cli_layers, other_layers) = self
.layers
.iter()
.cloned()
.partition(ConfigLayer::is_from_command_line);
let mut repo_config = Self {
layers: other_layers,
};
for path in repo_config_files {
// TODO: check if this file should be trusted:
// `mercurial/ui.py:427`
repo_config.add_trusted_file(path)?;
}
repo_config.layers.extend(cli_layers);
Ok(repo_config)
}
fn get_parse<'config, T: 'config>(
&'config self,
section: &[u8],
item: &[u8],
expected_type: &'static str,
parse: impl Fn(&'config [u8]) -> Option<T>,
) -> Result<Option<T>, ConfigValueParseError> {
match self.get_inner(&section, &item) {
Some((layer, v)) => match parse(&v.bytes) {
Some(b) => Ok(Some(b)),
None => Err(ConfigValueParseError {
origin: layer.origin.to_owned(),
line: v.line,
value: v.bytes.to_owned(),
section: section.to_owned(),
item: item.to_owned(),
expected_type,
}),
},
None => Ok(None),
}
}
/// Returns an `Err` if the first value found is not a valid UTF-8 string.
/// Otherwise, returns an `Ok(value)` if found, or `None`.
pub fn get_str(
&self,
section: &[u8],
item: &[u8],
) -> Result<Option<&str>, ConfigValueParseError> {
self.get_parse(section, item, "ASCII or UTF-8 string", |value| {
str::from_utf8(value).ok()
})
}
/// Returns an `Err` if the first value found is not a valid unsigned
/// integer. Otherwise, returns an `Ok(value)` if found, or `None`.
pub fn get_u32(
&self,
section: &[u8],
item: &[u8],
) -> Result<Option<u32>, ConfigValueParseError> {
self.get_parse(section, item, "valid integer", |value| {
str::from_utf8(value).ok()?.parse().ok()
})
}
/// Returns an `Err` if the first value found is not a valid file size
/// value such as `30` (default unit is bytes), `7 MB`, or `42.5 kb`.
/// Otherwise, returns an `Ok(value_in_bytes)` if found, or `None`.
pub fn get_byte_size(
&self,
section: &[u8],
item: &[u8],
) -> Result<Option<u64>, ConfigValueParseError> {
self.get_parse(section, item, "byte quantity", values::parse_byte_size)
}
/// Returns an `Err` if the first value found is not a valid boolean.
/// Otherwise, returns an `Ok(option)`, where `option` is the boolean if
/// found, or `None`.
pub fn get_option(
&self,
section: &[u8],
item: &[u8],
) -> Result<Option<bool>, ConfigValueParseError> {
self.get_parse(section, item, "boolean", values::parse_bool)
}
/// Returns the corresponding boolean in the config. Returns `Ok(false)`
/// if the value is not found, an `Err` if it's not a valid boolean.
pub fn get_bool(
&self,
section: &[u8],
item: &[u8],
) -> Result<bool, ConfigValueParseError> {
Ok(self.get_option(section, item)?.unwrap_or(false))
}
/// Returns the corresponding list-value in the config if found, or `None`.
///
/// This is appropriate for new configuration keys. The value syntax is
/// **not** the same as most existing list-valued config, which has Python
/// parsing implemented in `parselist()` in
/// `mercurial/utils/stringutil.py`. Faithfully porting that parsing
/// algorithm to Rust (including behavior that are arguably bugs)
/// turned out to be non-trivial and hasn’t been completed as of this
/// writing.
///
/// Instead, the "simple" syntax is: split on comma, then trim leading and
/// trailing whitespace of each component. Quotes or backslashes are not
/// interpreted in any way. Commas are mandatory between values. Values
/// that contain a comma are not supported.
pub fn get_simple_list(
&self,
section: &[u8],
item: &[u8],
) -> Option<impl Iterator<Item = &[u8]>> {
self.get(section, item).map(|value| {
value
.split(|&byte| byte == b',')
.map(|component| component.trim())
})
}
/// Returns the raw value bytes of the first one found, or `None`.
pub fn get(&self, section: &[u8], item: &[u8]) -> Option<&[u8]> {
self.get_inner(section, item)
.map(|(_, value)| value.bytes.as_ref())
}
/// Returns the layer and the value of the first one found, or `None`.
fn get_inner(
&self,
section: &[u8],
item: &[u8],
) -> Option<(&ConfigLayer, &ConfigValue)> {
for layer in self.layers.iter().rev() {
if !layer.trusted {
continue;
}
if let Some(v) = layer.get(&section, &item) {
return Some((&layer, v));
}
}
None
}
/// Return all keys defined for the given section
pub fn get_section_keys(&self, section: &[u8]) -> HashSet<&[u8]> {
self.layers
.iter()
.flat_map(|layer| layer.iter_keys(section))
.collect()
}
/// Get raw values bytes from all layers (even untrusted ones) in order
/// of precedence.
#[cfg(test)]
fn get_all(&self, section: &[u8], item: &[u8]) -> Vec<&[u8]> {
let mut res = vec![];
for layer in self.layers.iter().rev() {
if let Some(v) = layer.get(&section, &item) {
res.push(v.bytes.as_ref());
}
}
res
}
}
#[cfg(test)]
mod tests {
use super::*;
use pretty_assertions::assert_eq;
use std::fs::File;
use std::io::Write;
#[test]
fn test_include_layer_ordering() {
let tmpdir = tempfile::tempdir().unwrap();
let tmpdir_path = tmpdir.path();
let mut included_file =
File::create(&tmpdir_path.join("included.rc")).unwrap();
included_file.write_all(b"[section]\nitem=value1").unwrap();
let base_config_path = tmpdir_path.join("base.rc");
let mut config_file = File::create(&base_config_path).unwrap();
let data =
b"[section]\nitem=value0\n%include included.rc\nitem=value2\n\
[section2]\ncount = 4\nsize = 1.5 KB\nnot-count = 1.5\nnot-size = 1 ub";
config_file.write_all(data).unwrap();
let sources = vec![ConfigSource::AbsPath(base_config_path)];
let config = Config::load_from_explicit_sources(sources)
.expect("expected valid config");
let (_, value) = config.get_inner(b"section", b"item").unwrap();
assert_eq!(
value,
&ConfigValue {
bytes: b"value2".to_vec(),
line: Some(4)
}
);
let value = config.get(b"section", b"item").unwrap();
assert_eq!(value, b"value2",);
assert_eq!(
config.get_all(b"section", b"item"),
[b"value2", b"value1", b"value0"]
);
assert_eq!(config.get_u32(b"section2", b"count").unwrap(), Some(4));
assert_eq!(
config.get_byte_size(b"section2", b"size").unwrap(),
Some(1024 + 512)
);
assert!(config.get_u32(b"section2", b"not-count").is_err());
assert!(config.get_byte_size(b"section2", b"not-size").is_err());
}
}