annotate rust/hg-core/src/config/config.rs @ 48335:b7fde9237c92

rhg: Enable `rhg status` in most tests

This subcommand is disabled by default because of bugs that make some test fail.
Enable it in the rest of the tests in order to avoid regressing them.

As with `RHG_ON_UNSUPPORTED`, an environment variable is used instead of
a configuration file and `HGRCPATH` because some tests override `HGRCPATH`.

Running `unset RHG_STATUS` at the start of a test restores the default of
`rhg status` being disabled. Hopefully it can be increasingly removed
from test files as bugs are fixed.

Differential Revision: https://phab.mercurial-scm.org/D11756

// config.rs
//
// Copyright 2020
//      Valentin Gatien-Baron,
//      Raphaël Gomès <[e-mail]>
//
// 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 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_non_repo() -> 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",
        );
        config.add_for_environment_variable("RHG_STATUS", b"rhg", b"status");

        // 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)?
                    }
                }
            }
        }
        Ok(config)
    }

    pub fn load_cli_args_config(
        &mut self,
        cli_config_args: impl IntoIterator<Item = impl AsRef<[u8]>>,
    ) -> Result<(), ConfigError> {
        if let Some(layer) = ConfigLayer::parse_cli_args(cli_config_args)? {
            self.layers.push(layer)
        }
        Ok(())
    }

    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))
    }

    /// If there is an `item` value in `section`, parse and return a list of
    /// byte strings.
    pub fn get_list(
        &self,
        section: &[u8],
        item: &[u8],
    ) -> Option<Vec<Vec<u8>>> {
        self.get(section, item).map(values::parse_list)
    }

    /// 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());
    }
}