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//! Base paths for use with arti clients.
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//!
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//! This code is defined in `tor-config-path` rather than in `arti-client` so that other programs
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//! (notably `arti-rpc-client-core`) can use it.
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use std::{borrow::Cow, path::PathBuf};
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use directories::ProjectDirs;
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use once_cell::sync::Lazy;
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use crate::{CfgPathError, CfgPathResolver};
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/// A [`CfgPathResolver`] with the base variables configured for a `TorClientConfig`
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/// in `arti-client`.
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///
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/// A `TorClientConfig` may set additional variables on its resolver.
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///
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/// This should only be used by `TorClient` users
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/// and others that need to use the same variables.
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/// Libraries should be written in a
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/// resolver-agnostic way (shouldn't rely on resolving `ARTI_CONFIG` for example).
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///
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/// The supported variables are:
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///   * `ARTI_CACHE`: an arti-specific cache directory.
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///   * `ARTI_CONFIG`: an arti-specific configuration directory.
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///   * `ARTI_SHARED_DATA`: an arti-specific directory in the user's "shared
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///     data" space.
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///   * `ARTI_LOCAL_DATA`: an arti-specific directory in the user's "local
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///     data" space.
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///   * `PROGRAM_DIR`: the directory of the currently executing binary.
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///     See documentation for [`std::env::current_exe`] for security notes.
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///   * `USER_HOME`: the user's home directory.
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///
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/// These variables are implemented using the [`directories`] crate, and
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/// so should use appropriate system-specific overrides under the
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/// hood. (Some of those overrides are based on environment variables.)
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/// For more information, see that crate's documentation.
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pub fn arti_client_base_resolver() -> CfgPathResolver {
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    let arti_cache = project_dirs().map(|x| Cow::Owned(x.cache_dir().to_owned()));
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    let arti_config = project_dirs().map(|x| Cow::Owned(x.config_dir().to_owned()));
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    let arti_shared_data = project_dirs().map(|x| Cow::Owned(x.data_dir().to_owned()));
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    let arti_local_data = project_dirs().map(|x| Cow::Owned(x.data_local_dir().to_owned()));
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    let program_dir = get_program_dir().map(Cow::Owned);
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    let user_home = crate::home().map(Cow::Borrowed);
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    let mut resolver = CfgPathResolver::default();
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    resolver.set_var("ARTI_CACHE", arti_cache);
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    resolver.set_var("ARTI_CONFIG", arti_config);
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    resolver.set_var("ARTI_SHARED_DATA", arti_shared_data);
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    resolver.set_var("ARTI_LOCAL_DATA", arti_local_data);
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    resolver.set_var("PROGRAM_DIR", program_dir);
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    resolver.set_var("USER_HOME", user_home);
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    resolver
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}
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/// Return the directory holding the currently executing program.
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fn get_program_dir() -> Result<PathBuf, CfgPathError> {
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    let binary = std::env::current_exe().map_err(|_| CfgPathError::NoProgramPath)?;
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    let directory = binary.parent().ok_or(CfgPathError::NoProgramDir)?;
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    Ok(directory.to_owned())
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}
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/// Return a ProjectDirs object for the Arti project.
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fn project_dirs() -> Result<&'static ProjectDirs, CfgPathError> {
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    /// lazy cell holding the ProjectDirs object.
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    static PROJECT_DIRS: Lazy<Option<ProjectDirs>> =
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        Lazy::new(|| ProjectDirs::from("org", "torproject", "Arti"));
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    PROJECT_DIRS.as_ref().ok_or(CfgPathError::NoProjectDirs)
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}
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#[cfg(test)]
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mod test {
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    // @@ begin test lint list maintained by maint/add_warning @@
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    #![allow(clippy::bool_assert_comparison)]
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    #![allow(clippy::clone_on_copy)]
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    #![allow(clippy::dbg_macro)]
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    #![allow(clippy::mixed_attributes_style)]
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    #![allow(clippy::print_stderr)]
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    #![allow(clippy::print_stdout)]
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    #![allow(clippy::single_char_pattern)]
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    #![allow(clippy::unwrap_used)]
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    #![allow(clippy::unchecked_duration_subtraction)]
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    #![allow(clippy::useless_vec)]
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    #![allow(clippy::needless_pass_by_value)]
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    //! <!-- @@ end test lint list maintained by maint/add_warning @@ -->
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    use super::*;
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    use crate::CfgPath;
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    fn cfg_variables() -> impl IntoIterator<Item = (&'static str, PathBuf)> {
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        let list = [
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            ("ARTI_CACHE", project_dirs().unwrap().cache_dir()),
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            ("ARTI_CONFIG", project_dirs().unwrap().config_dir()),
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            ("ARTI_SHARED_DATA", project_dirs().unwrap().data_dir()),
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            ("ARTI_LOCAL_DATA", project_dirs().unwrap().data_local_dir()),
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            ("PROGRAM_DIR", &get_program_dir().unwrap()),
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            ("USER_HOME", crate::home().unwrap()),
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        ];
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        list.into_iter()
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            .map(|(a, b)| (a, b.to_owned()))
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            .collect::<Vec<_>>()
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    }
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    #[cfg(not(target_family = "windows"))]
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    #[test]
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    fn expand_variables() {
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        let path_resolver = arti_client_base_resolver();
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        for (var, val) in cfg_variables() {
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            let p = CfgPath::new(format!("${{{var}}}/example"));
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            assert_eq!(p.to_string(), format!("${{{var}}}/example"));
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            let expected = val.join("example");
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            assert_eq!(p.path(&path_resolver).unwrap().to_str(), expected.to_str());
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        }
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        let p = CfgPath::new("${NOT_A_REAL_VAR}/example".to_string());
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        assert!(p.path(&path_resolver).is_err());
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    }
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    #[cfg(target_family = "windows")]
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    #[test]
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    fn expand_variables() {
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        let path_resolver = arti_client_base_resolver();
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        for (var, val) in cfg_variables() {
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            let p = CfgPath::new(format!("${{{var}}}\\example"));
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            assert_eq!(p.to_string(), format!("${{{var}}}\\example"));
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            let expected = val.join("example");
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            assert_eq!(p.path(&path_resolver).unwrap().to_str(), expected.to_str());
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        }
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        let p = CfgPath::new("${NOT_A_REAL_VAR}\\example".to_string());
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        assert!(p.path(&path_resolver).is_err());
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    }
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}