Struct virtual_fs::mem_fs::file::FileHandle

pub(super) struct FileHandle {
    inode: usize,
    filesystem: FileSystem,
    readable: bool,
    writable: bool,
    append_mode: bool,
    cursor: u64,
    arc_file: Option<Result<Box<dyn VirtualFile + Send + Sync + 'static>>>,
}

A file handle. The file system doesn’t return the File type directly, but rather this FileHandle type, which contains the inode, the flags, and (a light copy of) the filesystem. For each operations, it is checked that the permissions allow the operations to be executed, and then it is checked that the file still exists in the file system. After that, the operation is delegated to the file itself.

Fields

inode: usize

filesystem: FileSystem

readable: bool

writable: bool

append_mode: bool

cursor: u64

arc_file: Option<Result<Box<dyn VirtualFile + Send + Sync + 'static>>>

Implementations

impl FileHandle

pub(super) fn new( inode: usize, filesystem: FileSystem, readable: bool, writable: bool, append_mode: bool, cursor: u64 ) -> Self

fn lazy_load_arc_file_mut(&mut self) -> Result<&mut dyn VirtualFile>

Trait Implementations

impl AsyncRead for FileHandle

fn poll_read( self: Pin<&mut Self>, cx: &mut Context<'_>, buf: &mut ReadBuf<'_> ) -> Poll<Result<()>>

Attempts to read from the AsyncRead into buf.

impl AsyncSeek for FileHandle

fn start_seek(self: Pin<&mut Self>, position: SeekFrom) -> Result<()>

Attempts to seek to an offset, in bytes, in a stream.

fn poll_complete( self: Pin<&mut Self>, cx: &mut Context<'_> ) -> Poll<Result<u64>>

Waits for a seek operation to complete.

impl AsyncWrite for FileHandle

fn poll_write( self: Pin<&mut Self>, cx: &mut Context<'_>, buf: &[u8] ) -> Poll<Result<usize>>

Attempt to write bytes from buf into the object.

fn poll_write_vectored( self: Pin<&mut Self>, cx: &mut Context<'_>, bufs: &[IoSlice<'_>] ) -> Poll<Result<usize>>

Like poll_write, except that it writes from a slice of buffers.

fn poll_flush(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<()>>

Attempts to flush the object, ensuring that any buffered data reach their destination.

fn poll_shutdown(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<()>>

Initiates or attempts to shut down this writer, returning success when the I/O connection has completely shut down.

fn is_write_vectored(&self) -> bool

Determines if this writer has an efficient poll_write_vectored implementation.

impl Clone for FileHandle

fn clone(&self) -> Self

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for FileHandle

fn fmt(&self, formatter: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl VirtualFile for FileHandle

fn last_accessed(&self) -> u64

the last time the file was accessed in nanoseconds as a UNIX timestamp

fn last_modified(&self) -> u64

the last time the file was modified in nanoseconds as a UNIX timestamp

fn created_time(&self) -> u64

the time at which the file was created in nanoseconds as a UNIX timestamp

fn set_times(&mut self, atime: Option<u64>, mtime: Option<u64>) -> Result<()>

sets accessed and modified time

fn size(&self) -> u64

the size of the file in bytes

fn set_len(&mut self, new_size: u64) -> Result<()>

Change the size of the file, if the new_size is greater than the current size the extra bytes will be allocated and zeroed

fn unlink(&mut self) -> Result<()>

Request deletion of the file

fn get_special_fd(&self) -> Option<u32>

Used for “special” files such as stdin, stdout and stderr. Always returns the same file descriptor (0, 1 or 2). Returns None on normal files

fn copy_reference( &mut self, src: Box<dyn VirtualFile + Send + Sync + 'static> ) -> BoxFuture<'_, Result<()>>

This method will copy a file from a source to this destination where the default is to do a straight byte copy however file system implementors may optimize this to do a zero copy

fn poll_read_ready( self: Pin<&mut Self>, cx: &mut Context<'_> ) -> Poll<Result<usize>>

Polls the file for when there is data to be read

fn poll_write_ready( self: Pin<&mut Self>, cx: &mut Context<'_> ) -> Poll<Result<usize>>

Polls the file for when it is available for writing

fn write_from_mmap(&mut self, offset: u64, size: u64) -> Result<()>

Writes to this file using an mmap offset and reference (this method only works for mmap optimized file systems)

fn is_open(&self) -> bool

Indicates if the file is opened or closed. This function must not block Defaults to a status of being constantly open