Struct VmoBuffer 

pub struct VmoBuffer {
    pub vmo: Option<Vmo>,
    pub vmo_usable_start: Option<u64>,
    pub close_weak_asap: Option<EventPair>,
    /* private fields */
}

Fields

vmo: Option<Vmo>

vmo can be un-set if a participant has only [fuchsia.sysmem2/BufferUsage.none] set to NONE_USAGE (explicitly or implicitly by [fuchsia.sysmem2/BufferCollection.SetConstraints] without constraints set).

vmo_usable_start: Option<u64>

Offset within the VMO of the first usable byte. Must be < the VMO’s size in bytes, and leave sufficient room for BufferMemorySettings.size_bytes before the end of the VMO.

Currently sysmem will always set this field to 0, and in future, sysmem won’t set this field to a non-zero value unless all participants have explicitly indicated support for non-zero vmo_usable_start (this mechanism does not exist as of this comment). A participant that hasn’t explicitly indicated support for non-zero vmo_usable_start (all current clients) should implicitly assume this field is set to 0 without actually checking this field.

close_weak_asap: Option<EventPair>

This field is set iff vmo is a sysmem weak VMO handle.

If the client sent SetWeakOk, the client must keep close_weak_asap around for as long as vmo, and must notice ZX_EVENTPAIR_PEER_CLOSED. If that signal occurs, the client must close vmo asap.

If the vmo is a sysmem weak VMO handle but the client didn’t send SetWeakOk, this means that a holder of a parent node sent SetWeakOk with for_child_nodes_also true, and the owner of that parent node is responsible for paying attention to close_weak_asap and informing child token participants to close handles. In this case the participant that never sent SetWeakOk is allowed to retain and/or pay attention to close_weak_asap (to close the handle faster, or for other reasons such as diagnosing overall buffer cleanup timing), but is not required to retain or pay attention to close_weak_asap.

If sysmem closing the sysmem end of close_weak_asap does not result in quick closure of all sysmem weak VMO handles to the buffer, that’s considered a VMO leak, and in that case sysmem will eventually complain loudly via syslog (currently 5s later).

Trait Implementations

impl Debug for VmoBuffer

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

Formats the value using the given formatter.

impl Decode<VmoBuffer, DefaultFuchsiaResourceDialect> for VmoBuffer

fn new_empty() -> Self

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<'_, DefaultFuchsiaResourceDialect>, offset: usize, depth: Depth, ) -> Result<()>

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

impl Default for VmoBuffer

fn default() -> VmoBuffer

Returns the “default value” for a type.

impl Encode<VmoBuffer, DefaultFuchsiaResourceDialect> for &mut VmoBuffer

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

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

impl PartialEq for VmoBuffer

fn eq(&self, other: &VmoBuffer) -> 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 ResourceTypeMarker for VmoBuffer

type Borrowed<'a> = &'a mut VmoBuffer

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

fn take_or_borrow<'a>( value: &'a mut <Self as TypeMarker>::Owned, ) -> Self::Borrowed<'a>

Cheaply converts from &mut Self::Owned to Self::Borrowed. For HandleBased types this is “take” (it returns an owned handle and replaces value with Handle::invalid), and for all other types it is “borrow” (just converts from one reference to another).

impl TypeMarker for VmoBuffer

type Owned = VmoBuffer

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 Standalone<DefaultFuchsiaResourceDialect> for VmoBuffer

impl StructuralPartialEq for VmoBuffer