rhai/src/engine_settings.rs
2021-06-28 18:06:05 +08:00

336 lines
11 KiB
Rust

//! Configuration settings for [`Engine`].
use crate::token::Token;
use crate::Engine;
use crate::{engine::Precedence, Identifier};
#[cfg(feature = "no_std")]
use std::prelude::v1::*;
#[cfg(not(feature = "unchecked"))]
use std::num::{NonZeroU64, NonZeroUsize};
impl Engine {
/// Control whether and how the [`Engine`] will optimize an [`AST`][crate::AST] after compilation.
///
/// Not available under `no_optimize`.
#[cfg(not(feature = "no_optimize"))]
#[inline(always)]
pub fn set_optimization_level(
&mut self,
optimization_level: crate::OptimizationLevel,
) -> &mut Self {
self.optimization_level = optimization_level;
self
}
/// The current optimization level.
/// It controls whether and how the [`Engine`] will optimize an [`AST`][crate::AST] after compilation.
///
/// Not available under `no_optimize`.
#[cfg(not(feature = "no_optimize"))]
#[inline(always)]
#[must_use]
pub fn optimization_level(&self) -> crate::OptimizationLevel {
self.optimization_level
}
/// Set the maximum levels of function calls allowed for a script in order to avoid
/// infinite recursion and stack overflows.
///
/// Not available under `unchecked` or `no_function`.
#[cfg(not(feature = "unchecked"))]
#[cfg(not(feature = "no_function"))]
#[inline(always)]
pub fn set_max_call_levels(&mut self, levels: usize) -> &mut Self {
self.limits.max_call_stack_depth = levels;
self
}
/// The maximum levels of function calls allowed for a script.
///
/// Not available under `unchecked` or `no_function`.
#[cfg(not(feature = "unchecked"))]
#[cfg(not(feature = "no_function"))]
#[inline(always)]
#[must_use]
pub const fn max_call_levels(&self) -> usize {
self.limits.max_call_stack_depth
}
/// Set the maximum number of operations allowed for a script to run to avoid
/// consuming too much resources (0 for unlimited).
///
/// Not available under `unchecked`.
#[cfg(not(feature = "unchecked"))]
#[inline(always)]
pub fn set_max_operations(&mut self, operations: u64) -> &mut Self {
self.limits.max_operations = NonZeroU64::new(operations);
self
}
/// The maximum number of operations allowed for a script to run (0 for unlimited).
///
/// Not available under `unchecked`.
#[cfg(not(feature = "unchecked"))]
#[inline(always)]
#[must_use]
pub const fn max_operations(&self) -> u64 {
if let Some(n) = self.limits.max_operations {
n.get()
} else {
0
}
}
/// Set the maximum number of imported [modules][crate::Module] allowed for a script.
///
/// Not available under `unchecked` or `no_module`.
#[cfg(not(feature = "unchecked"))]
#[cfg(not(feature = "no_module"))]
#[inline(always)]
pub fn set_max_modules(&mut self, modules: usize) -> &mut Self {
self.limits.max_modules = modules;
self
}
/// The maximum number of imported [modules][crate::Module] allowed for a script.
///
/// Not available under `unchecked` or `no_module`.
#[cfg(not(feature = "unchecked"))]
#[cfg(not(feature = "no_module"))]
#[inline(always)]
#[must_use]
pub const fn max_modules(&self) -> usize {
self.limits.max_modules
}
/// Set the depth limits for expressions (0 for unlimited).
///
/// Not available under `unchecked`.
#[cfg(not(feature = "unchecked"))]
#[inline(always)]
pub fn set_max_expr_depths(
&mut self,
max_expr_depth: usize,
#[cfg(not(feature = "no_function"))] max_function_expr_depth: usize,
) -> &mut Self {
self.limits.max_expr_depth = NonZeroUsize::new(max_expr_depth);
#[cfg(not(feature = "no_function"))]
{
self.limits.max_function_expr_depth = NonZeroUsize::new(max_function_expr_depth);
}
self
}
/// The depth limit for expressions (0 for unlimited).
///
/// Not available under `unchecked`.
#[cfg(not(feature = "unchecked"))]
#[inline(always)]
#[must_use]
pub const fn max_expr_depth(&self) -> usize {
if let Some(n) = self.limits.max_expr_depth {
n.get()
} else {
0
}
}
/// The depth limit for expressions in functions (0 for unlimited).
///
/// Not available under `unchecked` or `no_function`.
#[cfg(not(feature = "unchecked"))]
#[cfg(not(feature = "no_function"))]
#[inline(always)]
#[must_use]
pub const fn max_function_expr_depth(&self) -> usize {
if let Some(n) = self.limits.max_function_expr_depth {
n.get()
} else {
0
}
}
/// Set the maximum length of [strings][crate::ImmutableString] (0 for unlimited).
///
/// Not available under `unchecked`.
#[cfg(not(feature = "unchecked"))]
#[inline(always)]
pub fn set_max_string_size(&mut self, max_size: usize) -> &mut Self {
self.limits.max_string_size = NonZeroUsize::new(max_size);
self
}
/// The maximum length of [strings][crate::ImmutableString] (0 for unlimited).
///
/// Not available under `unchecked`.
#[cfg(not(feature = "unchecked"))]
#[inline(always)]
#[must_use]
pub const fn max_string_size(&self) -> usize {
if let Some(n) = self.limits.max_string_size {
n.get()
} else {
0
}
}
/// Set the maximum length of [arrays][crate::Array] (0 for unlimited).
///
/// Not available under `unchecked` or `no_index`.
#[cfg(not(feature = "unchecked"))]
#[cfg(not(feature = "no_index"))]
#[inline(always)]
pub fn set_max_array_size(&mut self, max_size: usize) -> &mut Self {
self.limits.max_array_size = NonZeroUsize::new(max_size);
self
}
/// The maximum length of [arrays][crate::Array] (0 for unlimited).
///
/// Not available under `unchecked` or `no_index`.
#[cfg(not(feature = "unchecked"))]
#[cfg(not(feature = "no_index"))]
#[inline(always)]
#[must_use]
pub fn max_array_size(&self) -> usize {
if let Some(n) = self.limits.max_array_size {
n.get()
} else {
0
}
}
/// Set the maximum size of [object maps][crate::Map] (0 for unlimited).
///
/// Not available under `unchecked` or `no_object`.
#[cfg(not(feature = "unchecked"))]
#[cfg(not(feature = "no_object"))]
#[inline(always)]
pub fn set_max_map_size(&mut self, max_size: usize) -> &mut Self {
self.limits.max_map_size = NonZeroUsize::new(max_size);
self
}
/// The maximum size of [object maps][crate::Map] (0 for unlimited).
///
/// Not available under `unchecked` or `no_object`.
#[cfg(not(feature = "unchecked"))]
#[cfg(not(feature = "no_object"))]
#[inline(always)]
#[must_use]
pub const fn max_map_size(&self) -> usize {
if let Some(n) = self.limits.max_map_size {
n.get()
} else {
0
}
}
/// Set the module resolution service used by the [`Engine`].
///
/// Not available under `no_module`.
#[cfg(not(feature = "no_module"))]
#[inline(always)]
pub fn set_module_resolver(
&mut self,
resolver: impl crate::ModuleResolver + 'static,
) -> &mut Self {
self.module_resolver = Some(Box::new(resolver));
self
}
/// Disable a particular keyword or operator in the language.
///
/// # Examples
///
/// The following will raise an error during parsing because the `if` keyword is disabled
/// and is recognized as a reserved symbol!
///
/// ```rust,should_panic
/// # fn main() -> Result<(), rhai::ParseError> {
/// use rhai::Engine;
///
/// let mut engine = Engine::new();
///
/// engine.disable_symbol("if"); // disable the 'if' keyword
///
/// engine.compile("let x = if true { 42 } else { 0 };")?;
/// // ^ 'if' is rejected as a reserved symbol
/// # Ok(())
/// # }
/// ```
///
/// The following will raise an error during parsing because the `+=` operator is disabled.
///
/// ```rust,should_panic
/// # fn main() -> Result<(), rhai::ParseError> {
/// use rhai::Engine;
///
/// let mut engine = Engine::new();
///
/// engine.disable_symbol("+="); // disable the '+=' operator
///
/// engine.compile("let x = 42; x += 1;")?;
/// // ^ unknown operator
/// # Ok(())
/// # }
/// ```
#[inline(always)]
pub fn disable_symbol(&mut self, symbol: impl Into<Identifier>) -> &mut Self {
self.disabled_symbols.insert(symbol.into());
self
}
/// Register a custom operator with a precedence into the language.
///
/// The operator must be a valid identifier (i.e. it cannot be a symbol).
///
/// The precedence cannot be zero.
///
/// # Example
///
/// ```rust
/// # fn main() -> Result<(), Box<rhai::EvalAltResult>> {
/// use rhai::Engine;
///
/// let mut engine = Engine::new();
///
/// // Register a custom operator called 'foo' and give it
/// // a precedence of 160 (i.e. between +|- and *|/).
/// engine.register_custom_operator("foo", 160).unwrap();
///
/// // Register a binary function named 'foo'
/// engine.register_fn("foo", |x: i64, y: i64| (x * y) - (x + y));
///
/// assert_eq!(
/// engine.eval_expression::<i64>("1 + 2 * 3 foo 4 - 5 / 6")?,
/// 15
/// );
/// # Ok(())
/// # }
/// ```
#[must_use]
pub fn register_custom_operator(
&mut self,
keyword: impl AsRef<str> + Into<Identifier>,
precedence: u8,
) -> Result<&mut Self, String> {
let precedence = Precedence::new(precedence);
if precedence.is_none() {
return Err("precedence cannot be zero".into());
}
match Token::lookup_from_syntax(keyword.as_ref()) {
// Standard identifiers, reserved keywords and custom keywords are OK
None | Some(Token::Reserved(_)) | Some(Token::Custom(_)) => (),
// Active standard keywords cannot be made custom
// Disabled keywords are OK
Some(token) if token.is_keyword() => {
if !self.disabled_symbols.contains(token.syntax().as_ref()) {
return Err(format!("'{}' is a reserved keyword", keyword.as_ref()).into());
}
}
// Active standard symbols cannot be made custom
Some(token) if token.is_symbol() => {
if !self.disabled_symbols.contains(token.syntax().as_ref()) {
return Err(format!("'{}' is a reserved operator", keyword.as_ref()).into());
}
}
// Active standard symbols cannot be made custom
Some(token) if !self.disabled_symbols.contains(token.syntax().as_ref()) => {
return Err(format!("'{}' is a reserved symbol", keyword.as_ref()).into())
}
// Disabled symbols are OK
Some(_) => (),
}
// Add to custom keywords
self.custom_keywords.insert(keyword.into(), precedence);
Ok(self)
}
}