xsd-parser 1.1.0

use std::fs::File;
use std::io::{BufReader, Error};

use url::Url;

use super::{ResolveRequest, Resolver};

/// Implements a [`Resolver`] that can be used to load local files.
#[must_use]
#[derive(Default, Debug)]
pub struct FileResolver;

impl FileResolver {
    /// Create a new [`FileResolver`] instance.
    pub fn new() -> Self {
        Self
    }
}

impl Resolver for FileResolver {
    type Buffer = BufReader<File>;
    type Error = Error;

    fn resolve(
        &mut self,
        req: &ResolveRequest,
    ) -> Result<Option<(Url, Self::Buffer)>, Self::Error> {
        let url = if let Some(current) = &req.current_location {
            current.join(&req.requested_location)
        } else {
            Url::parse(&req.requested_location)
        };

        let Ok(url) = url else {
            return Ok(None);
        };

        let Ok(path) = url.to_file_path() else {
            return Ok(None);
        };

        let file = File::open(&path)?;
        let buffer = BufReader::new(file);

        Ok(Some((url, buffer)))
    }
}