Struct JsonTreeReader 

pub struct JsonTreeReader<'transaction, 'budget, R, Q>
where
    Q: ResourceQuantity,
{ /* private fields */ }

Processes JSON values while borrowing one staged JSON value transaction.

Type Parameters

• R - Resource identity tracked by the borrowed transaction.
• Q - Quantity representation used for resource accounting.

Examples

use qubit_budget::json::{JsonResource, JsonValueBudget, JsonValueLimits};
use qubit_json::value::traverse::{
    JsonTreeContext, JsonTreeReader, JsonTreeVisitor,
};
use serde_json::Value;

struct Visitor;
impl JsonTreeVisitor for Visitor {
    type Error = std::convert::Infallible;

    fn enter(
        &mut self,
        _: &Value,
        _: JsonTreeContext<'_>,
    ) -> Result<(), Self::Error> {
        Ok(())
    }
}

let mut budget = JsonValueBudget::new(
    JsonValueLimits::<JsonResource, usize>::default(),
);
let mut transaction = budget.transaction();
let mut reader = JsonTreeReader::new(&mut transaction);
assert!(reader.process(&Value::Null, &mut Visitor).is_ok());

Implementations

impl<'transaction, 'budget, R, Q> JsonTreeReader<'transaction, 'budget, R, Q>

where R: Clone, Q: ResourceQuantity,

pub fn new( transaction: &'transaction mut JsonValueTransaction<'budget, R, Q>, ) -> Self

Creates a reader borrowing the supplied JSON value transaction.

Parameters

• transaction - Transaction receiving node and payload charges.

Returns

A reader borrowing transaction for its lifetime.

pub fn process<V>( &mut self, value: &Value, visitor: &mut V, ) -> Result<(), JsonTreeProcessError<R, Q, V::Error>>

where V: JsonTreeVisitor,

Processes every node in depth-first order without Rust recursion.

Type Parameters

• V - Visitor receiving admitted-node callbacks.

Parameters

• value - Root JSON value to process.
• visitor - Visitor invoked around each admitted node.

Returns

Ok(()) after the complete tree is processed.

Errors

Returns JsonTreeProcessError::Budget when resource admission fails, or JsonTreeProcessError::Visitor when the visitor rejects a node. Either error stops traversal immediately: remaining callbacks are not invoked, and a node may not receive a matching leave callback. Any visitor state or external side effects are the caller’s responsibility and are not undone. This method neither commits nor rolls back the borrowed transaction. A visitor error leaves prior charges staged in that transaction; a budget error rejects the transaction so it cannot be committed. Drop the transaction after an error and rebuild visitors that require balanced callbacks or clean state.

pub fn account( &mut self, value: &Value, ) -> Result<(), MeasuredBudgetError<R, Q>>

Accounts every node and payload without invoking a domain visitor.

The charges remain staged in the borrowed transaction. The caller decides whether to commit it after any surrounding work succeeds.

Parameters

• value - Root JSON value whose complete tree is admitted.

Returns

Ok(()) after every node and payload has been staged in the borrowed transaction.

Errors

Returns the first measured budget rejection encountered during the traversal.