arch_pkg_db/text/

local.rs

use super::{Text, TextCollection};
use core::error::Error;
use derive_more::{Display, Error};
use pipe_trait::Pipe;
use rayon::prelude::*;
use std::{
    fs::{read_dir, read_to_string},
    io::{self, ErrorKind},
    path::{Path, PathBuf},
};

/// Error when trying to read the directory of the local pacman database.
#[derive(Debug, Display, Error)]
#[display("Failed to read {path:?} as a directory: {error}")]
pub struct ReadLocalDbDirError<'a> {
    #[error(source)]
    error: io::Error,
    path: &'a Path,
}

impl<'a> ReadLocalDbDirError<'a> {
    /// Create an error.
    fn new(error: io::Error, path: &'a Path) -> Self {
        Self { error, path }
    }

    /// The source of this error.
    pub fn source(&self) -> &io::Error {
        &self.error
    }

    /// Path to the directory of the local pacman database.
    pub fn path(&self) -> &Path {
        self.path
    }
}

/// Error when trying to read a file in the local pacman database.
#[derive(Debug, Display, Error)]
#[display("Failed to read {path:?} as a text file: {error}")]
pub struct ReadLocalDbFileError {
    #[error(source)]
    error: io::Error,
    path: PathBuf,
}

impl ReadLocalDbFileError {
    /// Create an error.
    fn new(error: io::Error, path: PathBuf) -> Self {
        Self { error, path }
    }

    /// The source of this error.
    pub fn source(&self) -> &io::Error {
        &self.error
    }

    /// Path to the directory of the local pacman database.
    pub fn path(&self) -> &Path {
        &self.path
    }
}

/// Error when trying to load data from a local pacman database.
#[derive(Debug, Display)]
pub enum LoadLocalDbError<'a> {
    ReadDir(ReadLocalDbDirError<'a>),
    ReadFile(ReadLocalDbFileError),
}

// We implement Error manually because derive_more::Error was unable to handle it.
// Issue: <https://github.com/JelteF/derive_more/issues/511>
impl<'a> Error for LoadLocalDbError<'a> {
    fn source(&self) -> Option<&(dyn Error + 'static)> {
        match self {
            LoadLocalDbError::ReadDir(error) => Error::source(error),
            LoadLocalDbError::ReadFile(error) => Error::source(error),
        }
    }
}

impl TextCollection {
    /// Load data from a local pacman database.
    ///
    /// A local pacman database is a directory usually located at `$ARCH_ROOT/var/lib/pacman/local/`.
    pub fn extend_from_local_db<'path>(
        &mut self,
        local_db_path: &'path Path,
    ) -> Result<(), LoadLocalDbError<'path>> {
        let entries = local_db_path
            .pipe(read_dir)
            .map_err(|error| ReadLocalDbDirError::new(error, local_db_path))
            .map_err(LoadLocalDbError::ReadDir)?;

        for entry in entries {
            let Ok(entry) = entry else { continue };
            let Ok(file_type) = entry.file_type() else {
                continue;
            };
            if !file_type.is_dir() {
                continue;
            }
            let file_path = entry.path().join("desc");
            match read_to_string(&file_path) {
                Ok(text) => self.insert(text.into()),
                Err(error) if error.kind() == ErrorKind::NotFound => continue,
                Err(error) => {
                    return ReadLocalDbFileError::new(error, file_path)
                        .pipe(LoadLocalDbError::ReadFile)
                        .pipe(Err);
                }
            };
        }

        Ok(())
    }

    /// Load data from a local pacman database.
    ///
    /// A local pacman database is a directory usually located at `$ARCH_ROOT/var/lib/pacman/local/`.
    pub fn add_local_db(mut self, local_db_path: &'_ Path) -> Result<Self, LoadLocalDbError<'_>> {
        self.extend_from_local_db(local_db_path)?;
        Ok(self)
    }

    /// Load data from a local pacman database.
    ///
    /// A local pacman database is a directory usually located at `$ARCH_ROOT/var/lib/pacman/local/`.
    pub fn from_local_db(local_db_path: &'_ Path) -> Result<Self, LoadLocalDbError<'_>> {
        TextCollection::new().add_local_db(local_db_path)
    }

    /// Load data from a local pacman database in parallel.
    ///
    /// A local pacman database is a directory usually located at `$ARCH_ROOT/var/lib/pacman/local/`.
    pub fn par_extend_from_local_db<'path>(
        &mut self,
        local_db_path: &'path Path,
    ) -> Result<(), LoadLocalDbError<'path>> {
        let texts = local_db_path
            .pipe(read_dir)
            .map_err(|error| ReadLocalDbDirError::new(error, local_db_path))
            .map_err(LoadLocalDbError::ReadDir)?
            .par_bridge()
            .flatten()
            .filter(|entry| {
                entry
                    .file_type()
                    .ok()
                    .map(|file_type| file_type.is_dir())
                    .unwrap_or(false)
            })
            .map(|entry| -> Result<Option<String>, LoadLocalDbError> {
                let file_path = entry.path().join("desc");
                match read_to_string(&file_path) {
                    Ok(text) => Ok(Some(text)),
                    Err(error) if error.kind() == ErrorKind::NotFound => Ok(None),
                    Err(error) => ReadLocalDbFileError::new(error, file_path)
                        .pipe(LoadLocalDbError::ReadFile)
                        .pipe(Err),
                }
            })
            .collect::<Result<Vec<Option<String>>, LoadLocalDbError>>()?
            .into_iter()
            .flatten()
            .map(Text::from);
        self.extend(texts);
        Ok(())
    }

    /// Load data from a local pacman database in parallel.
    ///
    /// A local pacman database is a directory usually located at `$ARCH_ROOT/var/lib/pacman/local/`.
    pub fn par_add_local_db(
        mut self,
        local_db_path: &'_ Path,
    ) -> Result<Self, LoadLocalDbError<'_>> {
        self.par_extend_from_local_db(local_db_path)?;
        Ok(self)
    }

    /// Load data from a local pacman database in parallel.
    ///
    /// A local pacman database is a directory usually located at `$ARCH_ROOT/var/lib/pacman/local/`.
    pub fn par_from_local_db(local_db_path: &Path) -> Result<Self, LoadLocalDbError<'_>> {
        TextCollection::new().par_add_local_db(local_db_path)
    }
}