Struct sgx_tstd::untrusted::fs::File

pub struct File { /* fields omitted */ }

A reference to an open file on the filesystem.

An instance of a File can be read and/or written depending on what options it was opened with. Files also implement [Seek] to alter the logical cursor that the file contains internally.

Files are automatically closed when they go out of scope.

Methods

impl File

pub fn open<P: AsRef<Path>>(path: P) -> Result<File>

Attempts to open a file in read-only mode.

pub fn create<P: AsRef<Path>>(path: P) -> Result<File>

Opens a file in write-only mode.

This function will create a file if it does not exist, and will truncate it if it does.

pub fn sync_all(&self) -> Result<()>

Attempts to sync all OS-internal metadata to disk.

This function will attempt to ensure that all in-core data reaches the filesystem before returning.

pub fn sync_data(&self) -> Result<()>

This function is similar to sync_all, except that it may not synchronize file metadata to the filesystem.

This is intended for use cases that must synchronize content, but don't need the metadata on disk. The goal of this method is to reduce disk operations.

Note that some platforms may simply implement this in terms of sync_all.

pub fn set_len(&self, size: u64) -> Result<()>

Truncates or extends the underlying file, updating the size of this file to become size.

If the size is less than the current file's size, then the file will be shrunk. If it is greater than the current file's size, then the file will be extended to size and have all of the intermediate data filled in with 0s.

The file's cursor isn't changed. In particular, if the cursor was at the end and the file is shrunk using this operation, the cursor will now be past the end.

Errors

This function will return an error if the file is not opened for writing.

pub fn metadata(&self) -> Result<Metadata>

Queries metadata about the underlying file.

pub fn try_clone(&self) -> Result<File>

Create a new File instance that shares the same underlying file handle as the existing File instance. Reads, writes, and seeks will affect both File instances simultaneously.

pub fn set_permissions(&self, perm: Permissions) -> Result<()>

Changes the permissions on the underlying file.

Platform-specific behavior

This function currently corresponds to the fchmod function on Unix and the SetFileInformationByHandle function on Windows. Note that, this may change in the future.

Errors

This function will return an error if the user lacks permission change attributes on the underlying file. It may also return an error in other os-specific unspecified cases.

Trait Implementations

impl AsRawFd for File

fn as_raw_fd(&self) -> RawFd

Extracts the raw file descriptor.

impl FromRawFd for File

unsafe fn from_raw_fd(fd: RawFd) -> File

Constructs a new instance of Self from the given raw file descriptor.

impl IntoRawFd for File

fn into_raw_fd(self) -> RawFd

Consumes this object, returning the raw underlying file descriptor.

impl FileExt for File

fn read_at(&self, buf: &mut [u8], offset: u64) -> Result<usize>

Reads a number of bytes starting from a given offset.

fn write_at(&self, buf: &[u8], offset: u64) -> Result<usize>

Writes a number of bytes starting from a given offset.

impl Debug for File

fn fmt(&self, f: &mut Formatter) -> Result

Formats the value using the given formatter.

impl Read for File

fn read(&mut self, buf: &mut [u8]) -> Result<usize>

Pull some bytes from this source into the specified buffer, returning how many bytes were read.

unsafe fn initializer(&self) -> Initializer

Determines if this Reader can work with buffers of uninitialized memory.

fn read_to_end(&mut self, buf: &mut Vec<u8>) -> Result<usize>

Read all bytes until EOF in this source, placing them into buf.

fn read_to_string(&mut self, buf: &mut String) -> Result<usize>

Read all bytes until EOF in this source, appending them to buf.

fn read_exact(&mut self, buf: &mut [u8]) -> Result<()>

Read the exact number of bytes required to fill buf.

fn by_ref(&mut self) -> &mut Self where     Self: Sized,

Creates a "by reference" adaptor for this instance of Read.

Important traits for Bytes<R>

impl<R: Read> Iterator for Bytes<R> type Item = Result<u8>;

fn bytes(self) -> Bytes<Self> where     Self: Sized,

Transforms this Read instance to an Iterator over its bytes.

Important traits for Chars<R>

impl<R: Read> Iterator for Chars<R> type Item = Result<char, CharsError>;

fn chars(self) -> Chars<Self> where     Self: Sized,

Transforms this Read instance to an Iterator over chars.

fn chain<R: Read>(self, next: R) -> Chain<Self, R> where     Self: Sized,

Creates an adaptor which will chain this stream with another.

fn take(self, limit: u64) -> Take<Self> where     Self: Sized,

Creates an adaptor which will read at most limit bytes from it.

impl Write for File

fn write(&mut self, buf: &[u8]) -> Result<usize>

Write a buffer into this object, returning how many bytes were written.

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

Flush this output stream, ensuring that all intermediately buffered contents reach their destination.

fn write_all(&mut self, buf: &[u8]) -> Result<()>

Attempts to write an entire buffer into this write.

fn write_fmt(&mut self, fmt: Arguments) -> Result<()>

Writes a formatted string into this writer, returning any error encountered.

fn by_ref(&mut self) -> &mut Self where     Self: Sized,

Creates a "by reference" adaptor for this instance of Write.

impl Seek for File

fn seek(&mut self, pos: SeekFrom) -> Result<u64>

Seek to an offset, in bytes, in a stream.

impl<'a> Read for &'a File

fn read(&mut self, buf: &mut [u8]) -> Result<usize>

Pull some bytes from this source into the specified buffer, returning how many bytes were read.

unsafe fn initializer(&self) -> Initializer

Determines if this Reader can work with buffers of uninitialized memory.

fn read_to_end(&mut self, buf: &mut Vec<u8>) -> Result<usize>

Read all bytes until EOF in this source, placing them into buf.

fn read_to_string(&mut self, buf: &mut String) -> Result<usize>

Read all bytes until EOF in this source, appending them to buf.

fn read_exact(&mut self, buf: &mut [u8]) -> Result<()>

Read the exact number of bytes required to fill buf.

fn by_ref(&mut self) -> &mut Self where     Self: Sized,

Creates a "by reference" adaptor for this instance of Read.

Important traits for Bytes<R>

impl<R: Read> Iterator for Bytes<R> type Item = Result<u8>;

fn bytes(self) -> Bytes<Self> where     Self: Sized,

Transforms this Read instance to an Iterator over its bytes.

Important traits for Chars<R>

impl<R: Read> Iterator for Chars<R> type Item = Result<char, CharsError>;

fn chars(self) -> Chars<Self> where     Self: Sized,

Transforms this Read instance to an Iterator over chars.

fn chain<R: Read>(self, next: R) -> Chain<Self, R> where     Self: Sized,

Creates an adaptor which will chain this stream with another.

fn take(self, limit: u64) -> Take<Self> where     Self: Sized,

Creates an adaptor which will read at most limit bytes from it.

impl<'a> Write for &'a File

fn write(&mut self, buf: &[u8]) -> Result<usize>

Write a buffer into this object, returning how many bytes were written.

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

Flush this output stream, ensuring that all intermediately buffered contents reach their destination.

fn write_all(&mut self, buf: &[u8]) -> Result<()>

Attempts to write an entire buffer into this write.

fn write_fmt(&mut self, fmt: Arguments) -> Result<()>

Writes a formatted string into this writer, returning any error encountered.

fn by_ref(&mut self) -> &mut Self where     Self: Sized,

Creates a "by reference" adaptor for this instance of Write.

impl<'a> Seek for &'a File

fn seek(&mut self, pos: SeekFrom) -> Result<u64>

Seek to an offset, in bytes, in a stream.