Struct base::descriptor_reflection::FileSerdeWrapper
source · pub struct FileSerdeWrapper(pub File);Expand description
A simple wrapper around File that implements Serialize/Deserialize, which is useful when
the #[serde(with = "with_as_descriptor")] trait is infeasible, such as for a field with type
Option<File>.
Tuple Fields§
§0: FileMethods from Deref<Target = File>§
1.0.0 · sourcepub fn sync_all(&self) -> Result<(), Error>
pub fn sync_all(&self) -> Result<(), Error>
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(())
}1.0.0 · sourcepub fn sync_data(&self) -> Result<(), Error>
pub fn sync_data(&self) -> Result<(), Error>
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(())
}1.0.0 · sourcepub fn set_len(&self, size: u64) -> Result<(), Error>
pub fn set_len(&self, size: u64) -> Result<(), Error>
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.
1.0.0 · sourcepub fn metadata(&self) -> Result<Metadata, Error>
pub fn metadata(&self) -> Result<Metadata, Error>
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(())
}1.9.0 · sourcepub fn try_clone(&self) -> Result<File, Error>
pub fn try_clone(&self) -> Result<File, Error>
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(())
}1.16.0 · sourcepub fn set_permissions(&self, perm: Permissions) -> Result<(), Error>
pub fn set_permissions(&self, perm: Permissions) -> Result<(), Error>
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.
1.75.0 · sourcepub fn set_times(&self, times: FileTimes) -> Result<(), Error>
pub fn set_times(&self, times: FileTimes) -> Result<(), Error>
Changes the timestamps of the underlying file.
§Platform-specific behavior
This function currently corresponds to the futimens function on Unix (falling back to
futimes on macOS before 10.13) and the SetFileTime function on Windows. Note that this
may change in the future.
§Errors
This function will return an error if the user lacks permission to change timestamps on the underlying file. It may also return an error in other os-specific unspecified cases.
This function may return an error if the operating system lacks support to change one or
more of the timestamps set in the FileTimes structure.
§Examples
fn main() -> std::io::Result<()> {
use std::fs::{self, File, FileTimes};
let src = fs::metadata("src")?;
let dest = File::options().write(true).open("dest")?;
let times = FileTimes::new()
.set_accessed(src.accessed()?)
.set_modified(src.modified()?);
dest.set_times(times)?;
Ok(())
}1.75.0 · sourcepub fn set_modified(&self, time: SystemTime) -> Result<(), Error>
pub fn set_modified(&self, time: SystemTime) -> Result<(), Error>
Changes the modification time of the underlying file.
This is an alias for set_times(FileTimes::new().set_modified(time)).