Struct TraceFilter 

pub struct TraceFilter {
    pub bytecode: Option<Vec<u8>>,
    pub bytecode_v2: Option<Vec<u8>>,
    pub string_filter_chain: Option<StringFilterChain>,
    pub bytecode_overlay_v54: Option<Vec<u8>>,
    pub string_filter_chain_v54: Option<StringFilterChain>,
}

When set applies a post-filter to the trace contents using the filter provided. The filter is applied at ReadBuffers() time and works both in the case of IPC readback and write_into_file. This filter can be generated using tools/proto_filter -s schema.proto -F filter_out.bytes or -T filter_out.escaped_string (for .pbtx). See go/trace-filtering for design.

Introduced in Android S, but it was broken (b/195065199). Reintroduced in Android T with a different field number. Updated in Android U with a new bytecode version which supports string filtering.

The principles and terminology of string filtering is heavily inspired by iptables. A “rule” decide how strings should be filtered. Each rule contains a “policy” which indicates the algorithm to use for filtering. A “chain” is a list of rules which will be sequentially checked against each string.

The first rule which applies to the string terminates filtering for that string. If no rules apply, the string is left unchanged.

========================= Filter bytecode.

Fields

bytecode: Option<Vec<u8>>

The bytecode as implemented in Android T.

bytecode_v2: Option<Vec<u8>>

The bytecode as implemented in Android U. Adds support for string filtering.

string_filter_chain: Option<StringFilterChain>

bytecode_overlay_v54: Option<Vec<u8>>

Bytecode overlay for Perfetto v54+. This overlay is applied on top of bytecode_v2 to upgrade specific simple fields to new values. Old Perfetto versions ignore this field; new versions apply it.

The motivation for this is that adding new opcodes in a backwards compatible way while also minimizing config size is hard. Instead, the overlay mechanism allows us to “patch” specific fields in the original bytecode_v2 with new semantics.

See RFC 0011-subset-string-filter-rules.md for more info.

Note: Unlike bytecode_v2 (which uses implicit message indices via EndOfMessage markers), this overlay uses a triplet format with explicit indices: [msg_index, field_id << 3 | opcode, argument] … [checksum] Each entry is exactly 3 varints. The argument is 0 when not needed. Entries must be sorted by (msg_index, field_id).

The parser processes bytecode_v2 and this overlay simultaneously:

• any field not mentioned in the overlay is parsed as usual
• any field in the overlay but not in the bytecode_v2 is added with its overlay value
• any field in both the overlay and bytecode_v2 takes the value in the overlay, the bytecode_v2 value is ignored.

Note: despite the name, this was broken in v54 (the overlay was not passed through to the bytecode parser). Only works in v55+.

string_filter_chain_v54: Option<StringFilterChain>

String filter chain for Perfetto v54+. Rules in this chain either overwrite rules in string_filter_chain (if the name matches) or are appended (if the name doesn’t match). This allows modifying existing rules (e.g., changing policy) without duplicating the entire chain. Rules without a name are always appended. See /rfcs/0011-subset-string-filter-rules.md for design details. Introduced in: Perfetto v54.

Implementations

impl TraceFilter

pub fn bytecode(&self) -> &[u8]

Returns the value of bytecode, or the default value if bytecode is unset.

pub fn bytecode_v2(&self) -> &[u8]

Returns the value of bytecode_v2, or the default value if bytecode_v2 is unset.

pub fn bytecode_overlay_v54(&self) -> &[u8]

Returns the value of bytecode_overlay_v54, or the default value if bytecode_overlay_v54 is unset.

Trait Implementations

impl Clone for TraceFilter

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for TraceFilter

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

Formats the value using the given formatter.

impl Default for TraceFilter

fn default() -> Self

Returns the “default value” for a type.

impl Message for TraceFilter

fn encoded_len(&self) -> usize

Returns the encoded length of the message without a length delimiter.

fn clear(&mut self)

Clears the message, resetting all fields to their default.

fn encode(&self, buf: &mut impl BufMut) -> Result<(), EncodeError>

where Self: Sized,

Encodes the message to a buffer.

fn encode_to_vec(&self) -> Vec<u8>

where Self: Sized,

Encodes the message to a newly allocated buffer.

fn encode_length_delimited( &self, buf: &mut impl BufMut, ) -> Result<(), EncodeError>

where Self: Sized,

Encodes the message with a length-delimiter to a buffer.

fn encode_length_delimited_to_vec(&self) -> Vec<u8>

where Self: Sized,

Encodes the message with a length-delimiter to a newly allocated buffer.

fn decode(buf: impl Buf) -> Result<Self, DecodeError>

where Self: Default,

Decodes an instance of the message from a buffer.

fn decode_length_delimited(buf: impl Buf) -> Result<Self, DecodeError>

where Self: Default,

Decodes a length-delimited instance of the message from the buffer.

fn merge(&mut self, buf: impl Buf) -> Result<(), DecodeError>

where Self: Sized,

Decodes an instance of the message from a buffer, and merges it into self.

fn merge_length_delimited(&mut self, buf: impl Buf) -> Result<(), DecodeError>

where Self: Sized,

Decodes a length-delimited instance of the message from buffer, and merges it into self.

impl PartialEq for TraceFilter

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

Equality operator ==.

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

Inequality operator !=.

impl StructuralPartialEq for TraceFilter