Struct internment::LocalIntern [−][src]
pub struct LocalIntern<T> { /* fields omitted */ }
Expand description
A pointer to a thread-local interned object.
The interned object will be held in memory as long as the thread
is still running. Thus you can arrange a crude sort of arena
allocation by running code using LocalIntern
on a temporary
thread. Lifetime issues are as simple as when using Intern
.
LocalIntern
differs in that it is neigher Send
nor Share
, so
it cannot be used in a multithreaded manner. On the benefit side,
it is faster than Intern
, and the memory can be freed (by
running in a temporary thread).
Example
use internment::LocalIntern; let x = LocalIntern::new("hello"); let y = LocalIntern::new("world"); assert_ne!(x, y); assert_eq!(x, LocalIntern::new("hello")); assert_eq!(*x, "hello"); // dereference a LocalIntern like a pointer
Example with owned String
data
use internment::LocalIntern; let x = LocalIntern::new("hello".to_string()); let y = LocalIntern::<String>::from("world"); assert_ne!(x, y); assert_eq!(x, LocalIntern::from("hello")); assert_eq!(&*x, "hello"); // dereference a LocalIntern like a pointer
Implementations
Intern a value in a thread-local way. If this value has not
previously been interned, then new
will allocate a spot for
the value on the heap. Otherwise, it will return a pointer to
the object previously allocated.
Note that LocalIntern::new
is a bit slow.
Intern a value from a reference in a thread-local way (fastest).
If this value has not previously been
interned, then new
will allocate a spot for the value on the
heap and generate that value using T::from(val)
.
See how many objects have been interned. This may be helpful in analyzing memory use.
Trait Implementations
Returns the “default value” for a type. Read more
The hash implementation returns the hash of the pointer value, not the hash of the value pointed to. This should be irrelevant, since there is a unique pointer for every value, but it is observable, since you could compare the hash of the pointer with hash of the data itself.
This method returns an ordering between self
and other
values if one exists. Read more
This method tests less than (for self
and other
) and is used by the <
operator. Read more
This method tests less than or equal to (for self
and other
) and is used by the <=
operator. Read more
This method tests greater than (for self
and other
) and is used by the >
operator. Read more
An LocalIntern
is Copy
, which is unusal for a pointer. This
is safe because we never free the data pointed to by an
LocalIntern
until the thread itself is destroyed.
Auto Trait Implementations
impl<T> RefUnwindSafe for LocalIntern<T> where
T: RefUnwindSafe,
impl<T> !Send for LocalIntern<T>
impl<T> !Sync for LocalIntern<T>
impl<T> Unpin for LocalIntern<T>
impl<T> UnwindSafe for LocalIntern<T> where
T: RefUnwindSafe,
Blanket Implementations
Mutably borrows from an owned value. Read more
impl<T> CallHasher for T where
T: Hash,
impl<T> CallHasher for T where
T: Hash,