Struct JsRuntimeBuilder 

pub struct JsRuntimeBuilder { /* private fields */ }

Available on crate features js and std only.

Builder to configure and create a JsRuntime.

Cloneable, so it can double as a reusable blueprint: registered values share their backing storage and host functions are shared, making clones cheap. One blueprint can back any number of JsRuntimes and JsWorkers.

Implementations

impl JsRuntimeBuilder

pub const DEFAULT_LOOP_ITERATION_LIMIT: u64 = 1_000_000

Default instruction-fuel budget, expressed in approximate loop iterations for compatibility with the original API.

pub const DEFAULT_MEMORY_LIMIT: usize

Default maximum memory available to the private WebAssembly engine.

pub fn with_strict(self, strict: bool) -> JsRuntimeBuilder

Evaluate all scripts in strict mode, regardless of "use strict" directives.

pub fn set_strict(&mut self, strict: bool) -> &mut JsRuntimeBuilder

Evaluate all scripts in strict mode, regardless of "use strict" directives.

pub fn maybe_with_loop_iteration_limit( self, limit: Option<u64>, ) -> JsRuntimeBuilder

Limit script work with deterministic WebAssembly instruction fuel.

The value is scaled to preserve the existing approximate loop-count configuration. Unlike the original per-frame guard, the budget is cumulative across the complete evaluation or function call.

Defaults to Self::DEFAULT_LOOP_ITERATION_LIMIT; None removes the limit entirely. Exceeding it fails the evaluation with JsErrorKind::LimitExceeded.

pub fn maybe_set_loop_iteration_limit( &mut self, limit: Option<u64>, ) -> &mut JsRuntimeBuilder

Limit script work with deterministic WebAssembly instruction fuel.

The value is scaled to preserve the existing approximate loop-count configuration. Unlike the original per-frame guard, the budget is cumulative across the complete evaluation or function call.

Defaults to Self::DEFAULT_LOOP_ITERATION_LIMIT; None removes the limit entirely. Exceeding it fails the evaluation with JsErrorKind::LimitExceeded.

pub fn with_loop_iteration_limit(self, limit: u64) -> JsRuntimeBuilder

Limit script work with deterministic WebAssembly instruction fuel.

The value is scaled to preserve the existing approximate loop-count configuration. Unlike the original per-frame guard, the budget is cumulative across the complete evaluation or function call.

Defaults to Self::DEFAULT_LOOP_ITERATION_LIMIT; None removes the limit entirely. Exceeding it fails the evaluation with JsErrorKind::LimitExceeded.

pub fn set_loop_iteration_limit(&mut self, limit: u64) -> &mut JsRuntimeBuilder

Limit script work with deterministic WebAssembly instruction fuel.

The value is scaled to preserve the existing approximate loop-count configuration. Unlike the original per-frame guard, the budget is cumulative across the complete evaluation or function call.

Defaults to Self::DEFAULT_LOOP_ITERATION_LIMIT; None removes the limit entirely. Exceeding it fails the evaluation with JsErrorKind::LimitExceeded.

pub fn without_loop_iteration_limit(self) -> JsRuntimeBuilder

Limit script work with deterministic WebAssembly instruction fuel.

The value is scaled to preserve the existing approximate loop-count configuration. Unlike the original per-frame guard, the budget is cumulative across the complete evaluation or function call.

Defaults to Self::DEFAULT_LOOP_ITERATION_LIMIT; None removes the limit entirely. Exceeding it fails the evaluation with JsErrorKind::LimitExceeded.

pub fn unset_loop_iteration_limit(&mut self) -> &mut JsRuntimeBuilder

Limit script work with deterministic WebAssembly instruction fuel.

The value is scaled to preserve the existing approximate loop-count configuration. Unlike the original per-frame guard, the budget is cumulative across the complete evaluation or function call.

Defaults to Self::DEFAULT_LOOP_ITERATION_LIMIT; None removes the limit entirely. Exceeding it fails the evaluation with JsErrorKind::LimitExceeded.

pub fn with_memory_limit(self, limit: usize) -> JsRuntimeBuilder

Set the maximum memory available to the private WebAssembly engine.

This includes the JavaScript heap and engine state. Memory growth beyond the limit traps inside the WebAssembly container and poisons the runtime. Defaults to Self::DEFAULT_MEMORY_LIMIT.

pub fn set_memory_limit(&mut self, limit: usize) -> &mut JsRuntimeBuilder

Set the maximum memory available to the private WebAssembly engine.

This includes the JavaScript heap and engine state. Memory growth beyond the limit traps inside the WebAssembly container and poisons the runtime. Defaults to Self::DEFAULT_MEMORY_LIMIT.

pub fn maybe_with_execution_time_limit( self, limit: Option<Duration>, ) -> JsRuntimeBuilder

Wall-clock limit on each evaluation or call.

Wasmtime epoch interruption bounds all execution inside the engine component, including parsing, compilation, built-ins, snapshotting, and drained microtasks. The check is coarse-grained and does not run while a registered Rust host callback is executing.

Exceeding it fails the evaluation with JsErrorKind::LimitExceeded and poisons the runtime (JsRuntime::is_poisoned): the engine was aborted mid-execution, so every later operation fails with JsErrorKind::Setup. A JsWorker whose runtime got poisoned exits, failing pending jobs fast (fail-loud, like a panicking host function).

The frozen __rama_js_call__ global remains reserved for API compatibility and never exposes host data.

Defaults to None: no time limit.

pub fn maybe_set_execution_time_limit( &mut self, limit: Option<Duration>, ) -> &mut JsRuntimeBuilder

Wall-clock limit on each evaluation or call.

Wasmtime epoch interruption bounds all execution inside the engine component, including parsing, compilation, built-ins, snapshotting, and drained microtasks. The check is coarse-grained and does not run while a registered Rust host callback is executing.

Exceeding it fails the evaluation with JsErrorKind::LimitExceeded and poisons the runtime (JsRuntime::is_poisoned): the engine was aborted mid-execution, so every later operation fails with JsErrorKind::Setup. A JsWorker whose runtime got poisoned exits, failing pending jobs fast (fail-loud, like a panicking host function).

The frozen __rama_js_call__ global remains reserved for API compatibility and never exposes host data.

Defaults to None: no time limit.

pub fn with_execution_time_limit(self, limit: Duration) -> JsRuntimeBuilder

Wall-clock limit on each evaluation or call.

Wasmtime epoch interruption bounds all execution inside the engine component, including parsing, compilation, built-ins, snapshotting, and drained microtasks. The check is coarse-grained and does not run while a registered Rust host callback is executing.

Exceeding it fails the evaluation with JsErrorKind::LimitExceeded and poisons the runtime (JsRuntime::is_poisoned): the engine was aborted mid-execution, so every later operation fails with JsErrorKind::Setup. A JsWorker whose runtime got poisoned exits, failing pending jobs fast (fail-loud, like a panicking host function).

The frozen __rama_js_call__ global remains reserved for API compatibility and never exposes host data.

Defaults to None: no time limit.

pub fn set_execution_time_limit( &mut self, limit: Duration, ) -> &mut JsRuntimeBuilder

Wall-clock limit on each evaluation or call.

Wasmtime epoch interruption bounds all execution inside the engine component, including parsing, compilation, built-ins, snapshotting, and drained microtasks. The check is coarse-grained and does not run while a registered Rust host callback is executing.

Exceeding it fails the evaluation with JsErrorKind::LimitExceeded and poisons the runtime (JsRuntime::is_poisoned): the engine was aborted mid-execution, so every later operation fails with JsErrorKind::Setup. A JsWorker whose runtime got poisoned exits, failing pending jobs fast (fail-loud, like a panicking host function).

The frozen __rama_js_call__ global remains reserved for API compatibility and never exposes host data.

Defaults to None: no time limit.

pub fn without_execution_time_limit(self) -> JsRuntimeBuilder

Wall-clock limit on each evaluation or call.

Wasmtime epoch interruption bounds all execution inside the engine component, including parsing, compilation, built-ins, snapshotting, and drained microtasks. The check is coarse-grained and does not run while a registered Rust host callback is executing.

Exceeding it fails the evaluation with JsErrorKind::LimitExceeded and poisons the runtime (JsRuntime::is_poisoned): the engine was aborted mid-execution, so every later operation fails with JsErrorKind::Setup. A JsWorker whose runtime got poisoned exits, failing pending jobs fast (fail-loud, like a panicking host function).

The frozen __rama_js_call__ global remains reserved for API compatibility and never exposes host data.

Defaults to None: no time limit.

pub fn unset_execution_time_limit(&mut self) -> &mut JsRuntimeBuilder

Wall-clock limit on each evaluation or call.

Wasmtime epoch interruption bounds all execution inside the engine component, including parsing, compilation, built-ins, snapshotting, and drained microtasks. The check is coarse-grained and does not run while a registered Rust host callback is executing.

Exceeding it fails the evaluation with JsErrorKind::LimitExceeded and poisons the runtime (JsRuntime::is_poisoned): the engine was aborted mid-execution, so every later operation fails with JsErrorKind::Setup. A JsWorker whose runtime got poisoned exits, failing pending jobs fast (fail-loud, like a panicking host function).

The frozen __rama_js_call__ global remains reserved for API compatibility and never exposes host data.

Defaults to None: no time limit.

pub fn with_snapshot_limits(self, limits: JsSnapshotLimits) -> JsRuntimeBuilder

Configure resource limits for values copied out of the JS engine.

These limits apply to results, thrown values, and host-function arguments. The safe defaults are defined by JsSnapshotLimits.

pub fn set_snapshot_limits( &mut self, limits: JsSnapshotLimits, ) -> &mut JsRuntimeBuilder

Configure resource limits for values copied out of the JS engine.

These limits apply to results, thrown values, and host-function arguments. The safe defaults are defined by JsSnapshotLimits.

pub fn with_global( self, name: impl Into<JsStr>, global: impl IntoJsGlobal, ) -> JsRuntimeBuilder

Register a global: a value convertible Into<JsValue>, or a JsNamespace host object.

pub fn set_global( &mut self, name: impl Into<JsStr>, global: impl IntoJsGlobal, ) -> &mut JsRuntimeBuilder

Register a global: a value convertible Into<JsValue>, or a JsNamespace host object.

pub fn with_fn<A, F>(self, name: impl Into<JsStr>, f: F) -> JsRuntimeBuilder

where F: JsFn<A>,

Register a global host function with typed, extractor-style arguments (see JsFn).

pub fn set_fn<A, F>( &mut self, name: impl Into<JsStr>, f: F, ) -> &mut JsRuntimeBuilder

where F: JsFn<A>,

Register a global host function with typed, extractor-style arguments (see JsFn).

pub fn build(self) -> Result<JsRuntime, JsError>

Build the configured JsRuntime.

Trait Implementations

impl Clone for JsRuntimeBuilder

fn clone(&self) -> JsRuntimeBuilder

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for JsRuntimeBuilder

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

Formats the value using the given formatter.

impl Default for JsRuntimeBuilder

fn default() -> JsRuntimeBuilder

Returns the “default value” for a type.