Struct File

pub struct File { /* private fields */ }

Implementations

impl File

pub fn new() -> Result<Self>

Creates a new empty temporary file with read-write permissions.

pub async fn from_file_picker( filter_name: &str, extensions: &[impl ToString], ) -> Result<(Self, String)>

Attempts to prompt the user to choose a file from their local machine. Then creates a File allowing read-write access to that directory if they chose one successfully, along with the name of the file including the extension.

extensions should be a list of accepted file extensions for the file, without the leading .

pub async fn save(&self, filename: &str, filter_name: &str) -> Result<()>

Saves this file to a location of the user’s choice.

In native, this will open a file picker dialog, wait for the user to choose a location to save a file, and then copy this file to the new location. This function will wait for the user to finish picking a file location before returning.

In web, this will use the browser’s native file downloading method to save the file, which may or may not open a file picker. Due to platform limitations, this function will return immediately after making a download request and will not wait for the user to pick a file location if a file picker is shown.

You must flush the file yourself before saving. It will not be flushed for you.

filename should be the default filename, with extension, to show in the file picker if one is shown. filter_name should be the name of the file type shown in the part of the file picker where the user selects a file extension. filter_name works only in native builds; it is ignored in web builds.

Trait Implementations

impl AsyncRead for File

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

Attempt to read from the AsyncRead into buf.

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

Attempt to read from the AsyncRead into bufs using vectored IO operations.

impl AsyncSeek for File

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

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

impl AsyncWrite for File

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>>

Attempt to write bytes from bufs into the object using vectored IO operations.

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

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

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

Attempt to close the object.

impl Debug for File

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

Formats the value using the given formatter.

impl File for File

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

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

Truncates or extends the size of the file. If the file is extended, the file will be null-padded at the end. The file cursor never changes when truncating or extending, even if the cursor would be put outside the file bounds by this operation.

fn as_file(&mut self) -> &mut Self

where Self: Sized,

Casts a mutable reference to this file into &mut luminol_filesystem::File.

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.

fn read_vectored(&mut self, bufs: &mut [IoSliceMut<'_>]) -> Result<usize>

Like read, except that it reads into a slice of buffers.

fn is_read_vectored(&self) -> bool

🔬This is a nightly-only experimental API. (can_vector)

Determines if this Reader has an efficient read_vectored implementation.

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

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

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

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

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

Reads the exact number of bytes required to fill buf.

fn read_buf(&mut self, buf: BorrowedCursor<'_>) -> Result<(), Error>

🔬This is a nightly-only experimental API. (read_buf)

Pull some bytes from this source into the specified buffer.

fn read_buf_exact(&mut self, cursor: BorrowedCursor<'_>) -> Result<(), Error>

🔬This is a nightly-only experimental API. (read_buf)

Reads the exact number of bytes required to fill cursor.

fn by_ref(&mut self) -> &mut Self

where Self: Sized,

Creates a “by reference” adaptor for this instance of Read.

fn bytes(self) -> Bytes<Self>

where Self: Sized,

Transforms this Read instance to an Iterator over its bytes.

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

where R: Read, Self: Sized,

Creates an adapter which will chain this stream with another.

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

where Self: Sized,

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

impl Seek for File

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

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

fn rewind(&mut self) -> Result<(), Error>

Rewind to the beginning of a stream.

fn stream_len(&mut self) -> Result<u64, Error>

🔬This is a nightly-only experimental API. (seek_stream_len)

Returns the length of this stream (in bytes).

fn stream_position(&mut self) -> Result<u64, Error>

Returns the current seek position from the start of the stream.

fn seek_relative(&mut self, offset: i64) -> Result<(), Error>

Seeks relative to the current position.

impl Write for File

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

Writes a buffer into this writer, returning how many bytes were written.

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

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

fn write_vectored(&mut self, bufs: &[IoSlice<'_>]) -> Result<usize>

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

fn is_write_vectored(&self) -> bool

🔬This is a nightly-only experimental API. (can_vector)

Determines if this Writer has an efficient write_vectored implementation.

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

Attempts to write an entire buffer into this writer.

fn write_all_vectored(&mut self, bufs: &mut [IoSlice<'_>]) -> Result<(), Error>

🔬This is a nightly-only experimental API. (write_all_vectored)

Attempts to write multiple buffers into this writer.

fn write_fmt(&mut self, args: Arguments<'_>) -> Result<(), Error>

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” adapter for this instance of Write.

impl<'pin> Unpin for File

where PinnedFieldsOf<__File<'pin>>: Unpin,