qubit-mime 0.5.2

/*******************************************************************************
 *
 *    Copyright (c) 2026 Haixing Hu.
 *
 *    SPDX-License-Identifier: Apache-2.0
 *
 *    Licensed under the Apache License, Version 2.0.
 *
 ******************************************************************************/
//! File-backed media stream classifier helpers.

use std::fmt::Debug;
use std::io::Read;
use std::path::Path;

use crate::{
    MediaStreamClassifierBackend,
    MediaStreamType,
    MimeResult,
};

use super::media_stream_classifier_helpers::with_temp_reader;

/// Core implementation contract for classifiers that only operate on local files.
pub trait FileBasedMediaStreamClassifier: Debug + Send + Sync {
    /// Classifies one validated local file.
    ///
    /// # Parameters
    /// - `file`: Readable local media file.
    ///
    /// # Returns
    /// Media stream classification.
    ///
    /// # Errors
    /// Returns [`MimeError::Io`](crate::MimeError::Io) or another [`MimeError`](crate::MimeError)
    /// when backend classification fails.
    fn classify_by_local_file(&self, file: &Path) -> MimeResult<MediaStreamType>;
}

impl<T> MediaStreamClassifierBackend for T
where
    T: FileBasedMediaStreamClassifier,
{
    /// Delegates local-file classification to the file-based hook.
    fn classify_by_local_file(&self, file: &Path) -> MimeResult<MediaStreamType> {
        FileBasedMediaStreamClassifier::classify_by_local_file(self, file)
    }

    /// Stages stream content to a temporary local file before classification.
    fn classify_by_content(&self, reader: &mut dyn Read) -> MimeResult<MediaStreamType> {
        with_temp_reader(reader, |path| {
            FileBasedMediaStreamClassifier::classify_by_local_file(self, path)
        })
    }
}