kernel/object/capability/file/
mod.rs

1//! File operations capability module
2//! 
3//! This module provides system calls and traits for FileObject capability,
4//! which extends StreamOps with file-specific operations like seek and metadata.
5
6use crate::object::capability::stream::{StreamOps, StreamError};
7
8pub mod syscall;
9
10pub use syscall::{sys_file_seek, sys_file_truncate};
11
12/// Seek operations for file positioning
13#[derive(Debug, Clone, Copy)]
14pub enum SeekFrom {
15    /// Seek from the beginning of the file
16    Start(u64),
17    /// Seek relative to the current position
18    Current(i64),
19    /// Seek relative to the end of the file
20    End(i64),
21}
22
23/// Trait for file objects
24/// 
25/// This trait represents a file-like object that supports both stream operations
26/// and file-specific operations like seeking and metadata access.
27/// Directory reading is handled through normal read() operations.
28pub trait FileObject: StreamOps {
29    /// Seek to a position in the file stream
30    fn seek(&self, whence: SeekFrom) -> Result<u64, StreamError>;
31    
32    /// Get metadata about the file
33    fn metadata(&self) -> Result<crate::fs::FileMetadata, StreamError>;
34
35    /// Truncate the file to the specified size
36    /// 
37    /// This method changes the size of the file to the specified length.
38    /// If the new size is smaller than the current size, the file is truncated.
39    /// If the new size is larger, the file is extended with zero bytes.
40    /// 
41    /// # Arguments
42    /// 
43    /// * `size` - New size of the file in bytes
44    /// 
45    /// # Returns
46    /// 
47    /// * `Result<(), StreamError>` - Ok if the file was truncated successfully
48    /// 
49    /// # Errors
50    /// 
51    /// * `StreamError` - If the file is a directory or the operation is not supported
52    fn truncate(&self, size: u64) -> Result<(), StreamError> {
53        let _ = size;
54        Err(StreamError::NotSupported)
55    }
56}
kernel/object/capability/file/mod.rs

kernel/object/capability/file/
mod.rs
