Struct BufferMemorySettings 

pub struct BufferMemorySettings {
    pub size_bytes: Option<u64>,
    pub is_physically_contiguous: Option<bool>,
    pub is_secure: Option<bool>,
    pub coherency_domain: Option<CoherencyDomain>,
    pub heap: Option<Heap>,
    /* private fields */
}

These are memory-related settings for all buffers of a buffer collection.

Fields

size_bytes: Option<u64>

This field will always be set by sysmem.

Rule for producers: For BufferCollectionInfo with ImageFormatConstraints, storing an image of a given ImageFormat in a buffer of that BufferCollection is only allowed if the result of calling ImageFormatImageSize or a strictly equivalent computation is less than or equal to size_bytes.

Producer participants must stay within size_bytes when determining whether an image will fit in a buffer, even if the VMO’s size is larger than this.

Note: The VMO’s zx_vmo_get_stream_size / ZX_PROP_VMO_CONTENT_SIZE are not usable for this purpose, as that can’t be set (and get returns 0) for all VMO types that sysmem actually allocates (at least so far). In any case zx_vmo_get_stream_size is about current content size not max permitted content size.

Any future padding-only constraint which is irrelevant to a non-padding participant when locating each valid pixel’s valid data will be accounted for by checking ImageFormatImageSize() against size_bytes instead of the VMO size.

Following this rule allows producers to not need to worry about arbitrary padding requirements of other participants, including future-added padding-only constraints.

The bytes_per_row and rounding up to a tile size boundary are included in ImageFormatImageSize and accounted for in size_bytes, even though these two aspects are partially about padding. These two aspects are included in the ImageFormatImageSize calculation because these two aspects are also relevant to all participants that need to locate pixel data.

With the exception of bytes_per_row and rounding up to a tile size boundary when not PixelFormatModifier.Linear (and no other exceptions), this field does not include any extra VMO size padding that is added because of participant-specific padding constraint(s).

The same size_bytes value is sent to all participants.

This field is not page aligned. This value rounded up to zx_system_page_size() boundary is guaranteed to be less than or equal the buffer VMO size. In other words, the VMO is allowed to have more pages than implied by this value.

is_physically_contiguous: Option<bool>

This field will always be set by sysmem.

is_secure: Option<bool>

This field will always be set by sysmem.

coherency_domain: Option<CoherencyDomain>

This field will always be set by sysmem.

heap: Option<Heap>

The specific heap from which buffers are allocated.

This field will always be set by sysmem.

Trait Implementations

impl Clone for BufferMemorySettings

fn clone(&self) -> BufferMemorySettings

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for BufferMemorySettings

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

Formats the value using the given formatter.

impl<D> Decode<BufferMemorySettings, D> for BufferMemorySettings

where D: ResourceDialect,

fn new_empty() -> BufferMemorySettings

Creates a valid instance of Self. The specific value does not matter, since it will be overwritten by decode.

unsafe fn decode( &mut self, decoder: &mut Decoder<'_, D>, offset: usize, depth: Depth, ) -> Result<(), Error>

Decodes an object of type T from the decoder’s buffers into self.

impl Default for BufferMemorySettings

fn default() -> BufferMemorySettings

Returns the “default value” for a type.

impl<D> Encode<BufferMemorySettings, D> for &BufferMemorySettings

where D: ResourceDialect,

unsafe fn encode( self, encoder: &mut Encoder<'_, D>, offset: usize, depth: Depth, ) -> Result<(), Error>

Encodes the object into the encoder’s buffers. Any handles stored in the object are swapped for Handle::INVALID.

impl PartialEq for BufferMemorySettings

fn eq(&self, other: &BufferMemorySettings) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl TypeMarker for BufferMemorySettings

type Owned = BufferMemorySettings

The owned Rust type which this FIDL type decodes into.

fn inline_align(_context: Context) -> usize

Returns the minimum required alignment of the inline portion of the encoded object. It must be a (nonzero) power of two.

fn inline_size(_context: Context) -> usize

Returns the size of the inline portion of the encoded object, including padding for alignment. Must be a multiple of inline_align.

fn encode_is_copy() -> bool

Returns true if the memory layout of Self::Owned matches the FIDL wire format and encoding requires no validation. When true, we can optimize encoding arrays and vectors of Self::Owned to a single memcpy.

fn decode_is_copy() -> bool

Returns true if the memory layout of Self::Owned matches the FIDL wire format and decoding requires no validation. When true, we can optimize decoding arrays and vectors of Self::Owned to a single memcpy.

impl ValueTypeMarker for BufferMemorySettings

type Borrowed<'a> = &'a BufferMemorySettings

The Rust type to use for encoding. This is a particular Encode<Self> type cheaply obtainable from &Self::Owned. There are three cases:

fn borrow( value: &<BufferMemorySettings as TypeMarker>::Owned, ) -> <BufferMemorySettings as ValueTypeMarker>::Borrowed<'_>

Cheaply converts from &Self::Owned to Self::Borrowed.

impl Persistable for BufferMemorySettings

impl StructuralPartialEq for BufferMemorySettings