Struct windows_helpers::ResGuard

pub struct ResGuard<R, F>
where
    F: FnOnce(R),
{ /* private fields */ }

Holds a resource and a free-closure that is called when the guard is dropped.

Allows to couple resource acquisition and freeing, while treating the guard as the contained resource and ensuring freeing will happen. When writing the code, it’s also nice to transfer the documentation into everything that has to happen in one go without having to split it into upper and lower or here- and there-code. In a function, Rust’s drop order should ensure that later aquired resources are freed first.

For functions ending in Windows API function names (differently cased), you have to activate crate features. First, see the repository’s read-me. Then, derive the needed features from the Windows API function and the handle type associated with it.

Implementations

impl<R, F> ResGuard<R, F>

where F: FnOnce(R),

pub fn new(resource: R, free: F) -> Self

Should normally not be needed.

pub fn with_acquisition<A, E>(acquire: A, free: F) -> Result<Self, E>

where A: FnOnce() -> Result<R, E>,

For functions that return the resource.

pub fn with_mut_acquisition<A, T, E>(acquire: A, free: F) -> Result<Self, E>

where A: FnOnce(&mut R) -> Result<T, E>, R: Default,

For functions that provide the resource by means of an out-parameter.

pub fn two_with_mut_acquisition<A, T, E>( acquire_both: A, free_first: F, free_second: F ) -> Result<(Self, Self), E>

where A: FnOnce(&mut R, &mut R) -> Result<T, E>, R: Default,

For purpose, see Self::two_with_mut_acq_and_close_handle().

impl<R> ResGuard<R, fn(_: R)>

where R: CanInto<HANDLE> + TypeKind<TypeKind = CopyType> + Clone,

pub fn with_acq_and_close_handle<A, E>( acquire: A ) -> Result<ResGuard<R, fn(_: R)>, E>

where A: FnOnce() -> Result<R, E>,

pub fn with_mut_acq_and_close_handle<A, T, E>( acquire: A ) -> Result<ResGuard<R, fn(_: R)>, E>

where A: FnOnce(&mut R) -> Result<T, E>, R: Default,

impl<R> ResGuard<R, fn(_: R)>

where R: CanInto<HDC> + TypeKind<TypeKind = CopyType> + Clone,

pub fn with_acq_and_delete_dc<A, E>( acquire: A ) -> Result<ResGuard<R, fn(_: R)>, E>

where A: FnOnce() -> Result<R, E>,

pub fn with_mut_acq_and_delete_dc<A, T, E>( acquire: A ) -> Result<ResGuard<R, fn(_: R)>, E>

where A: FnOnce(&mut R) -> Result<T, E>, R: Default,

impl<R> ResGuard<R, fn(_: R)>

where R: CanInto<HGDIOBJ> + TypeKind<TypeKind = CopyType> + Clone,

pub fn with_acq_and_delete_object<A, E>( acquire: A ) -> Result<ResGuard<R, fn(_: R)>, E>

where A: FnOnce() -> Result<R, E>,

pub fn with_mut_acq_and_delete_object<A, T, E>( acquire: A ) -> Result<ResGuard<R, fn(_: R)>, E>

where A: FnOnce(&mut R) -> Result<T, E>, R: Default,

impl<R> ResGuard<R, fn(_: R)>

where R: CanInto<HGLOBAL> + TypeKind<TypeKind = CopyType> + Clone,

pub fn with_acq_and_global_free<A, E>( acquire: A ) -> Result<ResGuard<R, fn(_: R)>, E>

where A: FnOnce() -> Result<R, E>,

pub fn with_mut_acq_and_global_free<A, T, E>( acquire: A ) -> Result<ResGuard<R, fn(_: R)>, E>

where A: FnOnce(&mut R) -> Result<T, E>, R: Default,

impl<R> ResGuard<R, fn(_: R)>

where R: CanInto<HICON> + TypeKind<TypeKind = CopyType> + Clone,

pub fn with_acq_and_destroy_icon<A, E>( acquire: A ) -> Result<ResGuard<R, fn(_: R)>, E>

where A: FnOnce() -> Result<R, E>,

pub fn with_mut_acq_and_destroy_icon<A, T, E>( acquire: A ) -> Result<ResGuard<R, fn(_: R)>, E>

where A: FnOnce(&mut R) -> Result<T, E>, R: Default,

impl<R> ResGuard<R, fn(_: R)>

where R: CanInto<HLOCAL> + TypeKind<TypeKind = CopyType> + Clone,

pub fn with_acq_and_local_free<A, E>( acquire: A ) -> Result<ResGuard<R, fn(_: R)>, E>

where A: FnOnce() -> Result<R, E>,

pub fn with_mut_acq_and_local_free<A, T, E>( acquire: A ) -> Result<ResGuard<R, fn(_: R)>, E>

where A: FnOnce(&mut R) -> Result<T, E>, R: Default,

impl<R> ResGuard<R, fn(_: R)>

where R: CanInto<HMENU> + TypeKind<TypeKind = CopyType> + Clone,

pub fn with_acq_and_destroy_menu<A, E>( acquire: A ) -> Result<ResGuard<R, fn(_: R)>, E>

where A: FnOnce() -> Result<R, E>,

pub fn with_mut_acq_and_destroy_menu<A, T, E>( acquire: A ) -> Result<ResGuard<R, fn(_: R)>, E>

where A: FnOnce(&mut R) -> Result<T, E>, R: Default,

impl<R> ResGuard<R, fn(_: R)>

where R: CanInto<HMODULE> + TypeKind<TypeKind = CopyType> + Clone,

pub fn with_acq_and_free_library<A, E>( acquire: A ) -> Result<ResGuard<R, fn(_: R)>, E>

where A: FnOnce() -> Result<R, E>,

pub fn with_mut_acq_and_free_library<A, T, E>( acquire: A ) -> Result<ResGuard<R, fn(_: R)>, E>

where A: FnOnce(&mut R) -> Result<T, E>, R: Default,

impl ResGuard<PWSTR, fn(_: PWSTR)>

pub fn with_mut_pwstr_acq_and_local_free<A, T, E>(acquire: A) -> Result<Self, E>

where A: FnOnce(&mut PWSTR) -> Result<T, E>,

Useful for functions like ConvertSidToStringSidW() and FormatMessageW(), which allocate for you and are documented to require a call to LocalFree().

impl<R> ResGuard<R, fn(_: R)>

where R: CanInto<HANDLE> + TypeKind<TypeKind = CopyType> + Clone,

pub fn two_with_mut_acq_and_close_handle<A, T, E>( acquire_both: A ) -> Result<(ResGuard<R, fn(_: R)>, ResGuard<R, fn(_: R)>), E>

where A: FnOnce(&mut R, &mut R) -> Result<T, E>, R: Default,

For a function like CreatePipe() that returns two resources at once.

Trait Implementations

impl<R, F> Deref for ResGuard<R, F>

where F: FnOnce(R),

type Target = R

The resulting type after dereferencing.

fn deref(&self) -> &Self::Target

Dereferences the value.

impl<R, F> Drop for ResGuard<R, F>

where F: FnOnce(R),

fn drop(&mut self)

Executes the destructor for this type.