Struct LineParsingOptions 

pub struct LineParsingOptions {
    pub max_line_length: NumBytes,
    pub overflow_behavior: LineOverflowBehavior,
    pub buffer_compaction_threshold: Option<NumBytes>,
}

Configuration options for parsing lines from a stream.

Fields

max_line_length: NumBytes

Maximum length of a single line in bytes. When reached, further data won’t be appended to the current line. The line will be emitted in its current state.

Must be greater than zero for any line-consuming visitor (inspect_lines, collect_lines, wait_for_line, collect_lines_into_write, collect_lines_into_vec). Constructing such a consumer with max_line_length = 0 panics. If you want effectively unbounded line parsing — i.e. accept arbitrarily long lines from a trusted source — pass NumBytes::MAX explicitly instead of zero. Remember that a malicious or misbehaving stream that writes endless data without a line break would otherwise hold memory until the process runs out: the explicit MAX makes that decision visible at the call site.

Defaults to DEFAULT_MAX_LINE_LENGTH.

overflow_behavior: LineOverflowBehavior

What should happen when a line is too long?

When lossy buffering drops chunks before they reach the parser, line-based consumers conservatively discard any partial line and resynchronizes at the next newline instead of joining bytes across the gap.

Defaults to LineOverflowBehavior::DropAdditionalData.

buffer_compaction_threshold: Option<NumBytes>

Optional cap on each parser’s long-term-retained buffer capacity.

The parser keeps two BytesMut buffers (the in-progress line and the most-recently emitted line): each retains capacity for the parser’s lifetime, growing to fit the largest line they have ever held. For most workloads this is fine. The worst case is roughly 2 × max_line_length memory used per parser.

Set this to Some(n) when a stream has mostly small lines but occasional large outliers (especially under NumBytes::MAX / “trusted unbounded” line parsing) and you want the buffers to release their allocations after each outlier instead of staying at outlier-size forever. At the start of each LineParser::next_line call, any buffer whose capacity exceeds n is dropped and replaced with an empty buffer. The next line re-grows it from zero.

None (the default) preserves the “no compaction” behavior. Buffers stay at their largest observed size. A sensible enabled value could be 1.5 × typical_line_size. Setting it to close to (or below) typical line sizes will trigger reallocation almost every line and slow the parser unnecessarily. When your max_line_length is already small, you may ignore this setting if max consumption is not an issue on your system.

Compaction reduces the parser’s steady-state memory after outliers; it does not change the peak. Peak memory is bounded by max_line_length regardless of this setting. Compaction is also best-effort: a partially-buffered line that has not yet finished may briefly retain over-threshold capacity until the line completes.

Defaults to None.

Implementations

impl LineParsingOptions

pub fn builder() -> LineParsingOptionsBuilder<((), (), ())>

Create a builder for building LineParsingOptions. On the builder, call .max_line_length(...), .overflow_behavior(...), .buffer_compaction_threshold(...) to set the values of the fields. Finally, call .build() to create the instance of LineParsingOptions.

Trait Implementations

impl Clone for LineParsingOptions

fn clone(&self) -> LineParsingOptions

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for LineParsingOptions

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

Formats the value using the given formatter.

impl Default for LineParsingOptions

fn default() -> Self

Returns the “default value” for a type.

impl PartialEq for LineParsingOptions

fn eq(&self, other: &LineParsingOptions) -> 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 Copy for LineParsingOptions

impl Eq for LineParsingOptions

impl StructuralPartialEq for LineParsingOptions