integrations/fuse3/src/file.rs

// Licensed to the Apache Software Foundation (ASF) under one
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// distributed with this work for additional information
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// to you under the Apache License, Version 2.0 (the
// "License"); you may not use this file except in compliance
// with the License.  You may obtain a copy of the License at
//
//   http://www.apache.org/licenses/LICENSE-2.0
//
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// software distributed under the License is distributed on an
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use std::ffi::OsString;
use std::sync::Arc;

use fuse3::Errno;
use opendal::Writer;
use tokio::sync::Mutex;

/// Opened file represents file that opened in memory.
///
/// # FIXME
///
/// We should remove the `pub` filed to avoid unexpected changes.
pub struct OpenedFile {
    pub path: OsString,
    pub is_read: bool,
    pub inner_writer: Option<Arc<Mutex<InnerWriter>>>,
}

/// # FIXME
///
/// We need better naming and API for this struct.
pub struct InnerWriter {
    pub writer: Writer,
    pub written: u64,
}

/// File key is the key of opened file.
///
/// # FIXME
///
/// We should remove the `pub` filed to avoid unexpected changes.
#[derive(Debug, Clone, Copy)]
pub struct FileKey(pub usize);

impl TryFrom<u64> for FileKey {
    type Error = Errno;

    fn try_from(value: u64) -> std::result::Result<Self, Self::Error> {
        match value {
            0 => Err(Errno::from(libc::EBADF)),
            _ => Ok(FileKey(value as usize - 1)),
        }
    }
}

impl FileKey {
    pub fn to_fh(self) -> u64 {
        self.0 as u64 + 1 // ensure fh is not 0
    }
}