Enum tempfile_fast::PersistableTempFile [−][src]
pub enum PersistableTempFile {
Linux(File),
Fallback(NamedTempFile),
}
Expand description
An abstraction over different platform-specific temporary file optimisations.
Variants
Tuple Fields of Linux
0: File
Tuple Fields of Fallback
Implementations
Create a temporary file in a given filesystem, or, if the filesystem
does not support creating secure temporary files, create a
tempfile::NamedTempFile
.
Store this temporary file into a real file path.
The path must not exist and must be on the same mounted filesystem.
(Note: Linux permits a filesystem to be mounted at multiple points,
but the link()
function does not work across different mount points,
even if the same filesystem is mounted on both.)
Store this temporary file into a real name.
The path must be on the same mounted filesystem. It may exist, and will be overwritten.
This method may create a named temporary file, and, in pathological failure cases, may silently fail to remove this temporary file. Sorry.
(Note: Linux permits a filesystem to be mounted at multiple points,
but the link()
function does not work across different mount points,
even if the same filesystem is mounted on both.)
Methods from Deref<Target = File>
Attempts to sync all OS-internal metadata to disk.
This function will attempt to ensure that all in-memory data reaches the filesystem before returning.
This can be used to handle errors that would otherwise only be caught
when the File
is closed. Dropping a file will ignore errors in
synchronizing this in-memory data.
Examples
use std::fs::File;
use std::io::prelude::*;
fn main() -> std::io::Result<()> {
let mut f = File::create("foo.txt")?;
f.write_all(b"Hello, world!")?;
f.sync_all()?;
Ok(())
}
This function is similar to sync_all
, except that it might 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
.
Examples
use std::fs::File;
use std::io::prelude::*;
fn main() -> std::io::Result<()> {
let mut f = File::create("foo.txt")?;
f.write_all(b"Hello, world!")?;
f.sync_data()?;
Ok(())
}
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. Also, std::io::ErrorKind::InvalidInput will be returned if the desired length would cause an overflow due to the implementation specifics.
Examples
use std::fs::File;
fn main() -> std::io::Result<()> {
let mut f = File::create("foo.txt")?;
f.set_len(10)?;
Ok(())
}
Note that this method alters the content of the underlying file, even
though it takes &self
rather than &mut self
.
Queries metadata about the underlying file.
Examples
use std::fs::File;
fn main() -> std::io::Result<()> {
let mut f = File::open("foo.txt")?;
let metadata = f.metadata()?;
Ok(())
}
Creates 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.
Examples
Creates two handles for a file named foo.txt
:
use std::fs::File;
fn main() -> std::io::Result<()> {
let mut file = File::open("foo.txt")?;
let file_copy = file.try_clone()?;
Ok(())
}
Assuming there’s a file named foo.txt
with contents abcdef\n
, create
two handles, seek one of them, and read the remaining bytes from the
other handle:
use std::fs::File;
use std::io::SeekFrom;
use std::io::prelude::*;
fn main() -> std::io::Result<()> {
let mut file = File::open("foo.txt")?;
let mut file_copy = file.try_clone()?;
file.seek(SeekFrom::Start(3))?;
let mut contents = vec![];
file_copy.read_to_end(&mut contents)?;
assert_eq!(contents, b"def\n");
Ok(())
}
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.
Examples
fn main() -> std::io::Result<()> {
use std::fs::File;
let file = File::open("foo.txt")?;
let mut perms = file.metadata()?.permissions();
perms.set_readonly(true);
file.set_permissions(perms)?;
Ok(())
}
Note that this method alters the permissions of the underlying file,
even though it takes &self
rather than &mut self
.
Trait Implementations
Pull some bytes from this source into the specified buffer, returning how many bytes were read. Read more
Like read
, except that it reads into a slice of buffers. Read more
can_vector
)Determines if this Read
er has an efficient read_vectored
implementation. Read more
read_initializer
)Determines if this Read
er can work with buffers of uninitialized
memory. Read more
Read all bytes until EOF in this source, placing them into buf
. Read more
Read all bytes until EOF in this source, appending them to buf
. Read more
Read the exact number of bytes required to fill buf
. Read more
Creates a “by reference” adapter for this instance of Read
. Read more
Creates an adapter which will chain this stream with another. Read more
Pull some bytes from this source into the specified buffer, returning how many bytes were read. Read more
Like read
, except that it reads into a slice of buffers. Read more
can_vector
)Determines if this Read
er has an efficient read_vectored
implementation. Read more
read_initializer
)Determines if this Read
er can work with buffers of uninitialized
memory. Read more
Read all bytes until EOF in this source, placing them into buf
. Read more
Read all bytes until EOF in this source, appending them to buf
. Read more
Read the exact number of bytes required to fill buf
. Read more
Creates a “by reference” adapter for this instance of Read
. Read more
Creates an adapter which will chain this stream with another. Read more
Write a buffer into this writer, returning how many bytes were written. Read more
Flush this output stream, ensuring that all intermediately buffered contents reach their destination. Read more
can_vector
)Determines if this Write
r has an efficient write_vectored
implementation. Read more
Attempts to write an entire buffer into this writer. Read more
write_all_vectored
)Attempts to write multiple buffers into this writer. Read more
Writes a formatted string into this writer, returning any error encountered. Read more
Write a buffer into this writer, returning how many bytes were written. Read more
Flush this output stream, ensuring that all intermediately buffered contents reach their destination. Read more
can_vector
)Determines if this Write
r has an efficient write_vectored
implementation. Read more
Attempts to write an entire buffer into this writer. Read more
write_all_vectored
)Attempts to write multiple buffers into this writer. Read more
Writes a formatted string into this writer, returning any error encountered. Read more