Trait FileSystemTraits

Source

pub trait FileSystemTraits: Send + Sync {
Show 23 methods    // Required methods
    fn open(
        &self,
        task: TaskIdentifier,
        path: &Path,
        flags: Flags,
        time: Time,
        user: UserIdentifier,
        group: GroupIdentifier,
    ) -> Result<LocalFileIdentifier>;
    fn close(&self, file: LocalFileIdentifier) -> Result<()>;
    fn close_all(&self, task: TaskIdentifier) -> Result<()>;
    fn duplicate(
        &self,
        file: LocalFileIdentifier,
    ) -> Result<LocalFileIdentifier>;
    fn transfert(
        &self,
        new_task: TaskIdentifier,
        file: LocalFileIdentifier,
        new_file: Option<FileIdentifier>,
    ) -> Result<LocalFileIdentifier>;
    fn remove(&self, path: &Path) -> Result<()>;
    fn read(
        &self,
        file: LocalFileIdentifier,
        buffer: &mut [u8],
        time_type: Time,
    ) -> Result<Size>;
    fn write(
        &self,
        file: LocalFileIdentifier,
        buffer: &[u8],
        time_type: Time,
    ) -> Result<Size>;
    fn rename(&self, source: &Path, destination: &Path) -> Result<()>;
    fn set_position(
        &self,
        file: LocalFileIdentifier,
        position: &Position,
    ) -> Result<Size>;
    fn flush(&self, file: LocalFileIdentifier) -> Result<()>;
    fn create_directory(
        &self,
        path: &Path,
        time: Time,
        user: UserIdentifier,
        group: GroupIdentifier,
    ) -> Result<()>;
    fn open_directory(
        &self,
        path: &Path,
        task: TaskIdentifier,
    ) -> Result<LocalFileIdentifier>;
    fn read_directory(&self, file: LocalFileIdentifier) -> Result<Option<Entry>>;
    fn set_position_directory(
        &self,
        file: LocalFileIdentifier,
        position: Size,
    ) -> Result<()>;
    fn get_position_directory(&self, file: LocalFileIdentifier) -> Result<Size>;
    fn rewind_directory(&self, file: LocalFileIdentifier) -> Result<()>;
    fn close_directory(&self, file: LocalFileIdentifier) -> Result<()>;
    fn get_metadata(&self, file: LocalFileIdentifier) -> Result<Metadata>;
    fn set_metadata_from_path(
        &self,
        path: &Path,
        metadata: &Metadata,
    ) -> Result<()>;
    fn get_metadata_from_path(&self, path: &Path) -> Result<Metadata>;
    fn get_statistics(
        &self,
        file: LocalFileIdentifier,
    ) -> Result<Statistics_type>;
    fn get_mode(&self, file: LocalFileIdentifier) -> Result<Mode>;
}

Expand description

Core trait for all file system implementations.

This trait defines the complete interface that file systems must implement to integrate with the Xila operating system. It provides a POSIX-like API with additional features for multi-user environments, task isolation, and modern file system operations.

§Design Principles

§Task Isolation

All file operations are associated with a TaskIdentifier to ensure proper isolation between processes. File descriptors are local to each task.

§User Security

Operations include user and group identifiers for permission checking, ensuring secure multi-user operation.

§Concurrent Access

Implementations must handle concurrent access safely. The trait requires Send + Sync and implementations should use appropriate synchronization primitives like RwLock or Mutex.

§Non-blocking Operations

All operations should avoid blocking indefinitely. If an operation would block, implementations should return Error::RessourceBusy.

§File Operations

The trait supports standard file operations including:

Opening and closing files with various flags
Reading and writing data
Seeking to specific positions
File and directory creation/deletion
Metadata operations

§Directory Operations

Directory operations include:

Creating and removing directories
Opening directories for iteration
Reading directory entries
Position management for directory iteration

§Example Implementation Pattern


struct MyFileSystem {
    // Use RwLock for thread safety
    files: RwLock<CriticalSectionRawMutex, BTreeMap<Local_file_identifier_type, u32>>,
    // ... other fields
}

impl File_system_traits for MyFileSystem {
    fn Open(&self, task: TaskIdentifier, path: &Path_type, flags: Flags_type,
            time: Time_type, user: User_identifier_type, group: Group_identifier_type)
            -> Result<Local_file_identifier_type> {
        todo!()
    }
    // ... other methods would be implemented here
}

Required Methods§

Source

fn open( &self, task: TaskIdentifier, path: &Path, flags: Flags, time: Time, user: UserIdentifier, group: GroupIdentifier, ) -> Result<LocalFileIdentifier>

Open a file for I/O operations.

Opens a file at the specified path with the given flags and associates it with the specified task. The operation is subject to permission checking based on the provided user and group identifiers.

§Arguments

Task - Task identifier for file descriptor ownership
Path - Path to the file to open
Flags - Open flags (read, write, create, etc.)
Time - Current time for metadata updates
User - User identifier for permission checking
Group - Group identifier for permission checking

§Returns

Ok(Local_file_identifier_type) - File descriptor for the opened file
Err(Error) - Error if file cannot be opened

§Errors

Error::NotFound - File doesn’t exist and create flag not set
Error::PermissionDenied - Insufficient permissions
Error::AlreadyExists - File exists and exclusive create flag set
Error::TooManyOpenFiles - File descriptor limit reached

Source

fn close(&self, file: LocalFileIdentifier) -> Result<()>

Close a file and release its resources.

Closes the file associated with the given file identifier and releases any resources associated with it. After calling this method, the file identifier becomes invalid for the task.

§Arguments

file - File identifier to close

§Returns

Ok(()) - File successfully closed
Err(Error) - Error closing file

§Errors

Error::InvalidIdentifier - File identifier is invalid
Error::InputOutput - I/O error during close operation

Source

fn close_all(&self, task: TaskIdentifier) -> Result<()>

Close all files opened by a specific task.

This is typically called during task cleanup to ensure all file descriptors are properly released when a task terminates.

§Arguments

task - Task identifier whose files should be closed

§Returns

Ok(()) - All files successfully closed
Err(Error) - Error during cleanup

Source

fn duplicate(&self, file: LocalFileIdentifier) -> Result<LocalFileIdentifier>

Create a duplicate file identifier for the same file.

Creates a new file identifier that refers to the same open file. This is similar to the dup() system call in Unix systems. Both identifiers can be used independently and must be closed separately.

§Arguments

File - File identifier to duplicate

§Returns

Ok(Local_file_identifier_type) - New file identifier for the same file
Err(Error) - Error creating duplicate

§Errors

Error::InvalidIdentifier - Original file identifier is invalid
Error::TooManyOpenFiles - File descriptor limit reached

Source

fn transfert( &self, new_task: TaskIdentifier, file: LocalFileIdentifier, new_file: Option<FileIdentifier>, ) -> Result<LocalFileIdentifier>

Transfer a file identifier from one task to another.

Moves ownership of a file identifier from the current task to another task. This is useful for inter-process communication and file descriptor passing.