Struct fidl::encoding::TransactionHeader

#[repr(C)]
pub struct TransactionHeader {
    pub tx_id: u32,
    pub at_rest_flags: [u8; 2],
    pub dynamic_flags: u8,
    pub magic_number: u8,
    pub ordinal: u64,
}

Header for transactional FIDL messages

Fields

tx_id: u32

Transaction ID which identifies a request-response pair

at_rest_flags: [u8; 2]

Flags set for this message. MUST NOT be validated by bindings. Usually temporarily during migrations.

dynamic_flags: u8

Flags used for dynamically interpreting the request if it is unknown to the receiver.

magic_number: u8

Magic number indicating the message’s wire format. Two sides with different magic numbers are incompatible with each other.

ordinal: u64

Ordinal which identifies the FIDL method

Implementations

impl TransactionHeader

pub fn is_compatible(&self) -> bool

Returns whether the message containing this TransactionHeader is in a compatible wire format

impl TransactionHeader

pub fn new(tx_id: u32, ordinal: u64, dynamic_flags: DynamicFlags) -> Self

Creates a new transaction header with the default encode context and magic number.

pub fn new_full( tx_id: u32, ordinal: u64, context: Context, dynamic_flags: DynamicFlags, magic_number: u8 ) -> Self

Creates a new transaction header with a specific context and magic number.

pub fn is_epitaph(&self) -> bool

Returns true if the header is for an epitaph message.

pub fn validate_wire_format(&self) -> Result<()>

Returns an error if this header has an incompatible wire format.

pub fn validate_request_tx_id(&self, method_type: MethodType) -> Result<()>

Returns an error if this request header has an incorrect transaction id for the given method type.

pub fn at_rest_flags(&self) -> AtRestFlags

Returns the header’s migration flags as a AtRestFlags value.

pub fn dynamic_flags(&self) -> DynamicFlags

Returns the header’s dynamic flags as a DynamicFlags value.

pub fn decoding_context(&self) -> Context

Returns the context to use for decoding the message body associated with this header. During migrations, this is dependent on self.flags() and controls dynamic behavior in the read path.

Trait Implementations

impl Clone for TransactionHeader

fn clone(&self) -> TransactionHeader

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for TransactionHeader

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

Formats the value using the given formatter.

impl Decode<TransactionHeader> for TransactionHeader

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

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

impl Encode<TransactionHeader> for &TransactionHeader

unsafe fn encode( self, encoder: &mut Encoder<'_>, 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 TransactionHeader

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

This method tests for self and other values to be equal, and is used by ==.

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

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

impl TypeMarker for TransactionHeader

type Owned = TransactionHeader

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 TransactionHeader

type Borrowed<'a> = &'a TransactionHeader

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: &<Self as TypeMarker>::Owned) -> Self::Borrowed<'_>

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

impl Copy for TransactionHeader

impl Eq for TransactionHeader

impl StructuralPartialEq for TransactionHeader