Struct malloc_size_of::MallocSizeOfOps

pub struct MallocSizeOfOps {
    pub(crate) size_of_op: unsafe extern "C" fn(ptr: *const c_void) -> usize,
    pub(crate) enclosing_size_of_op: Option<unsafe extern "C" fn(ptr: *const c_void) -> usize>,
    pub(crate) have_seen_ptr_op: Option<Box<dyn FnMut(*const c_void) -> bool>>,
}

Operations used when measuring heap usage of data structures.

Fields

size_of_op: unsafe extern "C" fn(ptr: *const c_void) -> usize

A function that returns the size of a heap allocation.

enclosing_size_of_op: Option<unsafe extern "C" fn(ptr: *const c_void) -> usize>

Like size_of_op, but can take an interior pointer. Optional because not all allocators support this operation. If it’s not provided, some memory measurements will actually be computed estimates rather than real and accurate measurements.

have_seen_ptr_op: Option<Box<dyn FnMut(*const c_void) -> bool>>

Check if a pointer has been seen before, and remember it for next time. Useful when measuring Rcs and Arcs. Optional, because many places don’t need it.

Implementations

impl MallocSizeOfOps

pub fn new( size_of: unsafe extern "C" fn(ptr: *const c_void) -> usize, malloc_enclosing_size_of: Option<unsafe extern "C" fn(ptr: *const c_void) -> usize>, have_seen_ptr: Option<Box<dyn FnMut(*const c_void) -> bool>>, ) -> Self

pub(crate) fn is_empty<T: ?Sized>(ptr: *const T) -> bool

Check if an allocation is empty. This relies on knowledge of how Rust handles empty allocations, which may change in the future.

pub unsafe fn malloc_size_of<T: ?Sized>(&self, ptr: *const T) -> usize

Call size_of_op on ptr, first checking that the allocation isn’t empty, because some types (such as Vec) utilize empty allocations.

pub fn has_malloc_enclosing_size_of(&self) -> bool

Is an enclosing_size_of_op available?

pub unsafe fn malloc_enclosing_size_of<T>(&self, ptr: *const T) -> usize

Call enclosing_size_of_op, which must be available, on ptr, which must not be empty.

pub fn have_seen_ptr<T>(&mut self, ptr: *const T) -> bool

Call have_seen_ptr_op on ptr.