//! Preserves read-only mount errors for mutations through open descriptors.
use crate::*;
pub(crate) struct Readonly(pub Arc<dyn File>);
fn denied<T>() -> Result<T> {
    Err(error(io::ErrorKind::ReadOnlyFilesystem))
}
#[async_trait]
impl File for Readonly {
    async fn stat(&self) -> Result<Stat> {
        self.0.stat().await
    }
    async fn read(&self, offset: u64, length: usize) -> Result<Vec<u8>> {
        self.0.read(offset, length).await
    }
    async fn write(&self, _: u64, _: Vec<u8>) -> Result<usize> {
        denied()
    }
    async fn append(&self, _: Vec<u8>) -> Result<usize> {
        denied()
    }
    async fn set_size(&self, _: u64) -> Result<()> {
        denied()
    }
    async fn sync(&self) -> Result<()> {
        self.0.sync().await
    }
    async fn set_times(&self, _: Option<SystemTime>, _: Option<SystemTime>) -> Result<()> {
        denied()
    }
}