Struct JsonEncodeSession 

pub struct JsonEncodeSession<'a, R = JsonResource, Q = usize>
where
    Q: ResourceQuantity,
{ /* private fields */ }

Available on crate feature json only.

Mutable resource accounting for one JSON encoding operation.

Use Self::from_limits for a session that owns budgets created from immutable limits, or Self::borrowing_output when the caller owns the output and value budgets. Accepted output bytes are charged immediately; value measurements are staged until JsonEncodeAttempt::commit.

Type Parameters

• R - Caller-defined resource identity retained by limits and errors.
• Q - Exact unsigned quantity used for measurements and accounting.

Examples

use qubit_budget::json::JsonEncodeLimits;
use qubit_budget::json::JsonEncodeSession;
use qubit_budget::json::JsonMeasurement;

let limits = JsonEncodeLimits::builder()
    .max_output_bytes(4_usize)
    .max_nodes(1_usize)
    .build();
let mut session = JsonEncodeSession::from_limits(limits);
let mut attempt = session.begin_value();
attempt
    .try_consume_output_bytes(4)
    .expect("the output should fit");
attempt
    .try_admit(JsonMeasurement::Null { depth: 1 })
    .expect("the value should fit");
attempt.commit()?;
assert_eq!(session.output_budget().expect("output budget").used(), 4);

Implementations

impl<'a, R, Q> JsonEncodeSession<'a, R, Q>

where R: Clone, Q: ResourceQuantity,

pub fn borrowing_value(value: &'a mut JsonValueBudget<R, Q>) -> Self

Creates a session borrowing only a caller-owned value budget.

Parameters

• value - Caller-owned JSON value budget to update after a successful encode attempt.

Returns

Creates a session borrowing only a caller-owned value budget.

pub fn borrowing_output( output: &'a mut ResourceBudget<R, Q>, value: &'a mut JsonValueBudget<R, Q>, ) -> Self

Creates a session borrowing caller-owned output and value budgets.

Parameters

• output - Output supplied to this operation.
• value - Caller-owned JSON value budget to update after a successful encode attempt.

Returns

Creates a session borrowing caller-owned output and value budgets.

pub fn begin_value(&mut self) -> JsonEncodeAttempt<'_, R, Q>

Starts accounting for one complete JSON value.

The returned attempt charges accepted output immediately, but publishes staged JSON value accounting only after a successful commit. A value-admission failure poisons commit; dropping the attempt rolls back only the staged value state.

Returns

Starts accounting for one complete JSON value.

pub fn output_budget(&self) -> Option<&ResourceBudget<R, Q>>

Returns the output budget when configured.

Returns

Returns the output budget when configured.

None indicates that the corresponding limit or budget dimension is unconfigured.

pub fn max_output_bytes(&self) -> Option<Q>

Returns the configured output-byte maximum.

Returns

Returns the configured output-byte maximum.

None indicates that the corresponding limit or budget dimension is unconfigured.

pub fn value_budget(&self) -> &JsonValueBudget<R, Q>

Returns the value budget for read-only inspection.

Returns

Returns the value budget for read-only inspection.

impl<R, Q> JsonEncodeSession<'static, R, Q>

where R: Clone, Q: ResourceQuantity,

pub fn from_limits(limits: JsonEncodeLimits<R, Q>) -> Self

Creates a session that owns budgets initialized from immutable limits.

Parameters

• limits - Immutable encoding limits used to initialize owned accounting budgets.

Returns

Creates a session that owns budgets initialized from immutable limits.

Trait Implementations

impl<'a, R: Debug, Q> Debug for JsonEncodeSession<'a, R, Q>

where Q: ResourceQuantity + Debug,

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

Formats the value using the given formatter.