moq-dir 0.3.4

Media over QUIC
Documentation 
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use std::{
    collections::HashMap,
    sync::{Arc, Mutex},
};

use moq_transport::coding::TrackNamespace;
use moq_transport::serve::{ServeError, Tracks, TracksReader, TracksWriter};

use crate::{ListingReader, ListingWriter};

struct State {
    writer: TracksWriter,
    active: HashMap<String, ListingWriter>,
}

#[derive(Clone)]
pub struct Listings {
    state: Arc<Mutex<State>>,
    reader: TracksReader,
}

impl Listings {
    pub fn new(namespace: String) -> Self {
        let (writer, _, reader) = Tracks::new(TrackNamespace::from_utf8_path(&namespace)).produce();

        let state = State {
            writer,
            active: HashMap::new(),
        };

        Self {
            state: Arc::new(Mutex::new(state)),
            reader,
        }
    }

    // Returns a Registration that removes on drop.
    pub fn register(&mut self, path: &str) -> Result<Option<Registration>, ServeError> {
        let (prefix, base) = Self::prefix(path);

        let namespace = self.reader.namespace.to_utf8_path();

        if !prefix.starts_with(&namespace) {
            // Ignore anything that isn't in our namespace.
            return Ok(None);
        }

        // Remove the namespace prefix from the path.
        let prefix = &prefix[namespace.len()..];

        let mut state = self.state.lock().unwrap();
        if let Some(listing) = state.active.get_mut(prefix) {
            listing.insert(base.to_string())?;
        } else {
            log::info!("creating prefix: {}", prefix);
            let track = state.writer.create(prefix).unwrap();

            let mut listing = ListingWriter::new(track);
            listing.insert(base.to_string())?;
            state.active.insert(prefix.to_string(), listing);
        }

        log::info!("added listing: {} {}", prefix, base);

        Ok(Some(Registration {
            listing: self.clone(),
            prefix: prefix.to_string(),
            base: base.to_string(),
        }))
    }

    fn remove(&mut self, prefix: &str, base: &str) -> Result<(), ServeError> {
        let mut state = self.state.lock().unwrap();

        let listing = state.active.get_mut(prefix).ok_or(ServeError::NotFound)?;
        listing.remove(base)?;

        log::info!("removed listing: {} {}", prefix, base);

        if listing.is_empty() {
            log::info!("removed prefix: {}", prefix);
            state.active.remove(prefix);
            state.writer.remove(prefix);
        }

        Ok(())
    }

    pub fn subscribe(&mut self, name: &str) -> Option<ListingReader> {
        self.reader.subscribe(name).map(ListingReader::new)
    }

    pub fn tracks(&self) -> TracksReader {
        self.reader.clone()
    }

    // Returns the prefix for the string.
    // This is just the content before the last '/', like a directory name.
    // ex. "/foo/bar/baz" -> ("/foo/bar", "baz")
    pub fn prefix(path: &str) -> (&str, &str) {
        // Find the last '/' and return the parts.
        match path.rfind('.') {
            Some(index) => (&path[..index + 1], &path[index + 1..]),
            None => ("", path),
        }
    }
}

// Used to remove the registration on drop.
pub struct Registration {
    listing: Listings,
    prefix: String,
    base: String,
}

impl Drop for Registration {
    fn drop(&mut self) {
        self.listing.remove(&self.prefix, &self.base).ok();
    }
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn test_bucket() {
        assert!(Listings::prefix(".") == (".", ""));
        assert!(Listings::prefix(".foo") == (".", "foo"));
        assert!(Listings::prefix(".foo.") == (".foo.", ""));
        assert!(Listings::prefix(".foo.bar") == (".foo.", "bar"));
        assert!(Listings::prefix(".foo.bar.") == (".foo.bar.", ""));
        assert!(Listings::prefix(".foo.bar.baz") == (".foo.bar.", "baz"));
        assert!(Listings::prefix(".foo.bar.baz.") == (".foo.bar.baz.", ""));

        assert!(Listings::prefix("") == ("", ""));
        assert!(Listings::prefix("foo") == ("", "foo"));
        assert!(Listings::prefix("foo.") == ("foo.", ""));
        assert!(Listings::prefix("foo.bar") == ("foo.", "bar"));
        assert!(Listings::prefix("foo.bar.") == ("foo.bar.", ""));
        assert!(Listings::prefix("foo.bar.baz") == ("foo.bar.", "baz"));
        assert!(Listings::prefix("foo.bar.baz.") == ("foo.bar.baz.", ""));
    }
}