Struct file_guard::FileGuard

pub struct FileGuard<T: Deref<Target = File>> { /* private fields */ }

An RAII implementation of a “scoped lock” of a file. When this structure is dropped (falls out of scope), the lock will be unlocked.

This structure is created by the lock(), try_lock(), and lock_any() functions.

Implementations

impl<T> FileGuard<T>

where T: Deref<Target = File>,

pub fn lock_type(&self) -> Lock

Gets the Lock type currently held.

pub fn is_shared(&self) -> bool

Test if the currently held Lock type is Shared.

pub fn is_exclusive(&self) -> bool

Test if the currently held Lock type is Exclusive.

pub fn range(&self) -> Range<usize>

Gets the byte range of the held lock.

pub fn offset(&self) -> usize

Gets the byte offset of the held lock.

pub fn len(&self) -> usize

Gets the byte length of the held lock.

pub fn is_empty(&self) -> bool

Tests if the byte range of the lock has a length of zero.

pub fn downgrade(&mut self) -> Result<()>

Safely exchanges an Exclusive Lock for a Shared one.

If the currently held lock is already Shared, no change is made and the method succeeds. This exchange safely ensures no lock is released during operation. That is, no waiting Exclusive lock attempts may obtain the lock during the downgrade. Other Shared locks waiting will be granted a lock as a result, however.

Trait Implementations

impl<T> Debug for FileGuard<T>

where T: Deref<Target = File>,

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

Formats the value using the given formatter.

impl<T> Deref for FileGuard<T>

where T: Deref<Target = File>,

type Target = T

The resulting type after dereferencing.

fn deref(&self) -> &T

Dereferences the value.

impl<T> DerefMut for FileGuard<T>

where T: DerefMut<Target = File>,

fn deref_mut(&mut self) -> &mut T

Mutably dereferences the value.

impl<T> Drop for FileGuard<T>

where T: Deref<Target = File>,

fn drop(&mut self)

Executes the destructor for this type.

impl<T> FileGuardExt for FileGuard<T>

where T: Deref<Target = File>,

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

Upgrades a lock from Shared to Exclusive.

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

Attempts to upgrade a lock from Shared to Exclusive.