//! Main module defining the script evaluation [`Engine`]. use crate::ast::{Expr, FnCallExpr, Ident, OpAssignment, Stmt, AST_OPTION_FLAGS::*}; use crate::custom_syntax::CustomSyntax; use crate::dynamic::{map_std_type_name, AccessMode, Union, Variant}; use crate::fn_hash::{calc_fn_hash, get_hasher}; use crate::fn_native::{ CallableFunction, IteratorFn, OnDebugCallback, OnParseTokenCallback, OnPrintCallback, OnVarCallback, }; use crate::module::NamespaceRef; use crate::optimize::OptimizationLevel; use crate::packages::{Package, StandardPackage}; use crate::r#unsafe::unsafe_cast_var_name_to_lifetime; use crate::token::Token; use crate::{ Dynamic, EvalAltResult, Identifier, ImmutableString, Module, Position, RhaiResult, Scope, Shared, StaticVec, INT, }; #[cfg(feature = "no_std")] use std::prelude::v1::*; use std::{ any::{type_name, TypeId}, borrow::Cow, collections::{BTreeMap, BTreeSet}, fmt, hash::{Hash, Hasher}, iter::{FromIterator, Rev, Zip}, num::{NonZeroU8, NonZeroUsize}, ops::{Deref, DerefMut}, }; #[cfg(not(feature = "no_index"))] use crate::Array; #[cfg(not(feature = "no_object"))] use crate::Map; #[cfg(any(not(feature = "no_index"), not(feature = "no_object")))] use crate::ast::FnCallHashes; pub type Precedence = NonZeroU8; /// _(internals)_ A stack of imported [modules][Module]. /// Exported under the `internals` feature only. /// /// # Volatile Data Structure /// /// This type is volatile and may change. // // # Implementation Notes // // We cannot use Cow here because `eval` may load a [module][Module] and // the module name will live beyond the AST of the eval script text. // The best we can do is a shared reference. // // This implementation splits the module names from the shared modules to improve data locality. // Most usage will be looking up a particular key from the list and then getting the module that // corresponds to that key. #[derive(Clone, Default)] pub struct Imports { keys: StaticVec, modules: StaticVec>, } impl Imports { /// Create a new stack of imported [modules][Module]. #[inline(always)] #[must_use] pub fn new() -> Self { Self { keys: StaticVec::new(), modules: StaticVec::new(), } } /// Get the length of this stack of imported [modules][Module]. #[inline(always)] #[must_use] pub fn len(&self) -> usize { self.keys.len() } /// Is this stack of imported [modules][Module] empty? #[inline(always)] #[must_use] pub fn is_empty(&self) -> bool { self.keys.is_empty() } /// Get the imported [module][Module] at a particular index. #[inline(always)] #[must_use] pub fn get(&self, index: usize) -> Option> { self.modules.get(index).cloned() } /// Get the imported [module][Module] at a particular index. #[allow(dead_code)] #[inline(always)] #[must_use] pub(crate) fn get_mut(&mut self, index: usize) -> Option<&mut Shared> { self.modules.get_mut(index) } /// Get the index of an imported [module][Module] by name. #[inline] #[must_use] pub fn find(&self, name: &str) -> Option { self.keys .iter() .enumerate() .rev() .find_map(|(i, key)| if key == name { Some(i) } else { None }) } /// Push an imported [module][Module] onto the stack. #[inline(always)] pub fn push(&mut self, name: impl Into, module: impl Into>) { self.keys.push(name.into()); self.modules.push(module.into()); } /// Truncate the stack of imported [modules][Module] to a particular length. #[inline(always)] pub fn truncate(&mut self, size: usize) { self.keys.truncate(size); self.modules.truncate(size); } /// Get an iterator to this stack of imported [modules][Module] in reverse order. #[allow(dead_code)] #[inline] pub fn iter(&self) -> impl Iterator { self.keys .iter() .zip(self.modules.iter()) .rev() .map(|(name, module)| (name.as_str(), module.as_ref())) } /// Get an iterator to this stack of imported [modules][Module] in reverse order. #[allow(dead_code)] #[inline] pub(crate) fn iter_raw(&self) -> impl Iterator)> { self.keys.iter().rev().zip(self.modules.iter().rev()) } /// Get an iterator to this stack of imported [modules][Module] in forward order. #[allow(dead_code)] #[inline] pub(crate) fn scan_raw(&self) -> impl Iterator)> { self.keys.iter().zip(self.modules.iter()) } /// Does the specified function hash key exist in this stack of imported [modules][Module]? #[allow(dead_code)] #[inline(always)] #[must_use] pub fn contains_fn(&self, hash: u64) -> bool { self.modules.iter().any(|m| m.contains_qualified_fn(hash)) } /// Get the specified function via its hash key from this stack of imported [modules][Module]. #[inline] #[must_use] pub fn get_fn(&self, hash: u64) -> Option<(&CallableFunction, Option<&Identifier>)> { self.modules .iter() .rev() .find_map(|m| m.get_qualified_fn(hash).map(|f| (f, m.id_raw()))) } /// Does the specified [`TypeId`][std::any::TypeId] iterator exist in this stack of /// imported [modules][Module]? #[allow(dead_code)] #[inline(always)] #[must_use] pub fn contains_iter(&self, id: TypeId) -> bool { self.modules.iter().any(|m| m.contains_qualified_iter(id)) } /// Get the specified [`TypeId`][std::any::TypeId] iterator from this stack of imported /// [modules][Module]. #[inline] #[must_use] pub fn get_iter(&self, id: TypeId) -> Option { self.modules .iter() .rev() .find_map(|m| m.get_qualified_iter(id)) } } impl IntoIterator for Imports { type Item = (Identifier, Shared); type IntoIter = Zip>, Rev; 3]>>>; #[inline] fn into_iter(self) -> Self::IntoIter { self.keys .into_iter() .rev() .zip(self.modules.into_iter().rev()) } } impl, M: Into>> FromIterator<(K, M)> for Imports { fn from_iter>(iter: T) -> Self { let mut lib = Self::new(); lib.extend(iter); lib } } impl, M: Into>> Extend<(K, M)> for Imports { fn extend>(&mut self, iter: T) { iter.into_iter().for_each(|(k, m)| { self.keys.push(k.into()); self.modules.push(m.into()); }) } } impl fmt::Debug for Imports { fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { f.write_str("Imports")?; if self.is_empty() { f.debug_map().finish() } else { f.debug_map() .entries(self.keys.iter().zip(self.modules.iter())) .finish() } } } #[cfg(not(feature = "unchecked"))] #[cfg(debug_assertions)] #[cfg(not(feature = "no_function"))] pub const MAX_CALL_STACK_DEPTH: usize = 8; #[cfg(not(feature = "unchecked"))] #[cfg(debug_assertions)] pub const MAX_EXPR_DEPTH: usize = 32; #[cfg(not(feature = "unchecked"))] #[cfg(not(feature = "no_function"))] #[cfg(debug_assertions)] pub const MAX_FUNCTION_EXPR_DEPTH: usize = 16; #[cfg(not(feature = "unchecked"))] #[cfg(not(debug_assertions))] #[cfg(not(feature = "no_function"))] pub const MAX_CALL_STACK_DEPTH: usize = 64; #[cfg(not(feature = "unchecked"))] #[cfg(not(debug_assertions))] pub const MAX_EXPR_DEPTH: usize = 64; #[cfg(not(feature = "unchecked"))] #[cfg(not(feature = "no_function"))] #[cfg(not(debug_assertions))] pub const MAX_FUNCTION_EXPR_DEPTH: usize = 32; pub const MAX_DYNAMIC_PARAMETERS: usize = 16; pub const KEYWORD_PRINT: &str = "print"; pub const KEYWORD_DEBUG: &str = "debug"; pub const KEYWORD_TYPE_OF: &str = "type_of"; pub const KEYWORD_EVAL: &str = "eval"; pub const KEYWORD_FN_PTR: &str = "Fn"; pub const KEYWORD_FN_PTR_CALL: &str = "call"; pub const KEYWORD_FN_PTR_CURRY: &str = "curry"; #[cfg(not(feature = "no_closure"))] pub const KEYWORD_IS_SHARED: &str = "is_shared"; pub const KEYWORD_IS_DEF_VAR: &str = "is_def_var"; #[cfg(not(feature = "no_function"))] pub const KEYWORD_IS_DEF_FN: &str = "is_def_fn"; pub const KEYWORD_THIS: &str = "this"; #[cfg(not(feature = "no_function"))] pub const KEYWORD_GLOBAL: &str = "global"; #[cfg(not(feature = "no_object"))] pub const FN_GET: &str = "get$"; #[cfg(not(feature = "no_object"))] pub const FN_SET: &str = "set$"; #[cfg(any(not(feature = "no_index"), not(feature = "no_object")))] pub const FN_IDX_GET: &str = "index$get$"; #[cfg(any(not(feature = "no_index"), not(feature = "no_object")))] pub const FN_IDX_SET: &str = "index$set$"; #[cfg(not(feature = "no_function"))] pub const FN_ANONYMOUS: &str = "anon$"; /// Standard equality comparison operator. pub const OP_EQUALS: &str = "=="; /// Standard method function for containment testing. /// The `in` operator is implemented as a call to this method. pub const OP_CONTAINS: &str = "contains"; /// Standard concatenation operator token. pub const TOKEN_OP_CONCAT: Token = Token::PlusAssign; /// Method of chaining. #[cfg(any(not(feature = "no_index"), not(feature = "no_object")))] #[derive(Debug, Clone, Copy, Eq, PartialEq, Hash)] enum ChainType { /// Indexing. #[cfg(not(feature = "no_index"))] Indexing, /// Dotting. #[cfg(not(feature = "no_object"))] Dotting, } /// Value of a chaining argument. #[cfg(any(not(feature = "no_index"), not(feature = "no_object")))] #[derive(Debug, Clone, Hash)] enum ChainArgument { /// Dot-property access. #[cfg(not(feature = "no_object"))] Property(Position), /// Arguments to a dot method call. /// Wrapped values are the arguments plus the [position][Position] of the first argument. #[cfg(not(feature = "no_object"))] MethodCallArgs(StaticVec, Position), /// Index value and [position][Position]. #[cfg(not(feature = "no_index"))] IndexValue(Dynamic, Position), } #[cfg(any(not(feature = "no_index"), not(feature = "no_object")))] impl ChainArgument { /// Return the index value. #[inline(always)] #[cfg(not(feature = "no_index"))] #[must_use] pub fn into_index_value(self) -> Option { match self { Self::IndexValue(value, _) => Some(value), #[cfg(not(feature = "no_object"))] _ => None, } } /// Return the list of method call arguments. #[inline(always)] #[cfg(not(feature = "no_object"))] #[must_use] pub fn into_fn_call_args(self) -> Option<(StaticVec, Position)> { match self { Self::MethodCallArgs(values, pos) => Some((values, pos)), _ => None, } } } #[cfg(not(feature = "no_object"))] impl From<(StaticVec, Position)> for ChainArgument { #[inline(always)] fn from((values, pos): (StaticVec, Position)) -> Self { Self::MethodCallArgs(values, pos) } } #[cfg(not(feature = "no_index"))] impl From<(Dynamic, Position)> for ChainArgument { #[inline(always)] fn from((value, pos): (Dynamic, Position)) -> Self { Self::IndexValue(value, pos) } } /// Get the chaining type for an [`Expr`]. #[cfg(any(not(feature = "no_index"), not(feature = "no_object")))] fn match_chaining_type(expr: &Expr) -> ChainType { match expr { #[cfg(not(feature = "no_index"))] Expr::Index(_, _, _) => ChainType::Indexing, #[cfg(not(feature = "no_object"))] Expr::Dot(_, _, _) => ChainType::Dotting, _ => unreachable!("`expr` should only be `Index` or `Dot`, but got {:?}", expr), } } /// A type that encapsulates a mutation target for an expression with side effects. #[derive(Debug)] pub enum Target<'a> { /// The target is a mutable reference to a `Dynamic` value somewhere. RefMut(&'a mut Dynamic), /// The target is a mutable reference to a Shared `Dynamic` value. /// It holds both the access guard and the original shared value. #[cfg(not(feature = "no_closure"))] LockGuard((crate::dynamic::DynamicWriteLock<'a, Dynamic>, Dynamic)), /// The target is a temporary `Dynamic` value (i.e. the mutation can cause no side effects). TempValue(Dynamic), /// The target is a bit inside an [`INT`][crate::INT]. /// This is necessary because directly pointing to a bit inside an [`INT`][crate::INT] is impossible. #[cfg(not(feature = "no_index"))] BitField(&'a mut Dynamic, usize, Dynamic), /// The target is a character inside a String. /// This is necessary because directly pointing to a char inside a String is impossible. #[cfg(not(feature = "no_index"))] StringChar(&'a mut Dynamic, usize, Dynamic), } impl<'a> Target<'a> { /// Is the `Target` a reference pointing to other data? #[allow(dead_code)] #[inline] #[must_use] pub const fn is_ref(&self) -> bool { match self { Self::RefMut(_) => true, #[cfg(not(feature = "no_closure"))] Self::LockGuard(_) => true, Self::TempValue(_) => false, #[cfg(not(feature = "no_index"))] Self::BitField(_, _, _) => false, #[cfg(not(feature = "no_index"))] Self::StringChar(_, _, _) => false, } } /// Is the `Target` a temp value? #[inline] #[must_use] pub const fn is_temp_value(&self) -> bool { match self { Self::RefMut(_) => false, #[cfg(not(feature = "no_closure"))] Self::LockGuard(_) => false, Self::TempValue(_) => true, #[cfg(not(feature = "no_index"))] Self::BitField(_, _, _) => false, #[cfg(not(feature = "no_index"))] Self::StringChar(_, _, _) => false, } } /// Is the `Target` a shared value? #[cfg(not(feature = "no_closure"))] #[inline] #[must_use] pub fn is_shared(&self) -> bool { match self { Self::RefMut(r) => r.is_shared(), #[cfg(not(feature = "no_closure"))] Self::LockGuard(_) => true, Self::TempValue(r) => r.is_shared(), #[cfg(not(feature = "no_index"))] Self::BitField(_, _, _) => false, #[cfg(not(feature = "no_index"))] Self::StringChar(_, _, _) => false, } } /// Is the `Target` a specific type? #[allow(dead_code)] #[inline] #[must_use] pub fn is(&self) -> bool { match self { Self::RefMut(r) => r.is::(), #[cfg(not(feature = "no_closure"))] Self::LockGuard((r, _)) => r.is::(), Self::TempValue(r) => r.is::(), #[cfg(not(feature = "no_index"))] Self::BitField(_, _, _) => TypeId::of::() == TypeId::of::(), #[cfg(not(feature = "no_index"))] Self::StringChar(_, _, _) => TypeId::of::() == TypeId::of::(), } } /// Get the value of the `Target` as a `Dynamic`, cloning a referenced value if necessary. #[inline] #[must_use] pub fn take_or_clone(self) -> Dynamic { match self { Self::RefMut(r) => r.clone(), // Referenced value is cloned #[cfg(not(feature = "no_closure"))] Self::LockGuard((_, orig)) => orig, // Original value is simply taken Self::TempValue(v) => v, // Owned value is simply taken #[cfg(not(feature = "no_index"))] Self::BitField(_, _, value) => value, // Boolean is taken #[cfg(not(feature = "no_index"))] Self::StringChar(_, _, ch) => ch, // Character is taken } } /// Take a `&mut Dynamic` reference from the `Target`. #[inline(always)] #[must_use] pub fn take_ref(self) -> Option<&'a mut Dynamic> { match self { Self::RefMut(r) => Some(r), _ => None, } } /// Convert a shared or reference `Target` into a target with an owned value. #[inline(always)] #[must_use] pub fn into_owned(self) -> Target<'static> { self.take_or_clone().into() } /// Propagate a changed value back to the original source. /// This has no effect except for string indexing. #[inline] pub fn propagate_changed_value(&mut self) -> Result<(), Box> { match self { Self::RefMut(_) | Self::TempValue(_) => (), #[cfg(not(feature = "no_closure"))] Self::LockGuard(_) => (), #[cfg(not(feature = "no_index"))] Self::BitField(value, index, new_val) => { // Replace the bit at the specified index position let new_bit = new_val.as_bool().map_err(|err| { Box::new(EvalAltResult::ErrorMismatchDataType( "bool".to_string(), err.to_string(), Position::NONE, )) })?; let value = &mut *value .write_lock::() .expect("`BitField` holds `INT`"); let index = *index; if index < std::mem::size_of_val(value) * 8 { let mask = 1 << index; if new_bit { *value |= mask; } else { *value &= !mask; } } else { unreachable!("bit-field index out of bounds: {}", index); } } #[cfg(not(feature = "no_index"))] Self::StringChar(s, index, new_val) => { // Replace the character at the specified index position let new_ch = new_val.as_char().map_err(|err| { Box::new(EvalAltResult::ErrorMismatchDataType( "char".to_string(), err.to_string(), Position::NONE, )) })?; let s = &mut *s .write_lock::() .expect("`StringChar` holds `ImmutableString`"); let index = *index; *s = s .chars() .enumerate() .map(|(i, ch)| if i == index { new_ch } else { ch }) .collect(); } } Ok(()) } } impl<'a> From<&'a mut Dynamic> for Target<'a> { #[inline] fn from(value: &'a mut Dynamic) -> Self { #[cfg(not(feature = "no_closure"))] if value.is_shared() { // Cloning is cheap for a shared value let container = value.clone(); return Self::LockGuard(( value.write_lock::().expect("cast to `Dynamic`"), container, )); } Self::RefMut(value) } } impl Deref for Target<'_> { type Target = Dynamic; #[inline] fn deref(&self) -> &Dynamic { match self { Self::RefMut(r) => *r, #[cfg(not(feature = "no_closure"))] Self::LockGuard((r, _)) => &**r, Self::TempValue(ref r) => r, #[cfg(not(feature = "no_index"))] Self::BitField(_, _, ref r) => r, #[cfg(not(feature = "no_index"))] Self::StringChar(_, _, ref r) => r, } } } impl AsRef for Target<'_> { #[inline(always)] fn as_ref(&self) -> &Dynamic { self } } impl DerefMut for Target<'_> { #[inline] fn deref_mut(&mut self) -> &mut Dynamic { match self { Self::RefMut(r) => *r, #[cfg(not(feature = "no_closure"))] Self::LockGuard((r, _)) => r.deref_mut(), Self::TempValue(ref mut r) => r, #[cfg(not(feature = "no_index"))] Self::BitField(_, _, ref mut r) => r, #[cfg(not(feature = "no_index"))] Self::StringChar(_, _, ref mut r) => r, } } } impl AsMut for Target<'_> { #[inline(always)] fn as_mut(&mut self) -> &mut Dynamic { self } } impl> From for Target<'_> { #[inline(always)] #[must_use] fn from(value: T) -> Self { Self::TempValue(value.into()) } } /// _(internals)_ An entry in a function resolution cache. /// Exported under the `internals` feature only. /// /// # Volatile Data Structure /// /// This type is volatile and may change. #[derive(Debug, Clone)] pub struct FnResolutionCacheEntry { /// Function. pub func: CallableFunction, /// Optional source. pub source: Option, } /// _(internals)_ A function resolution cache. /// Exported under the `internals` feature only. /// /// # Volatile Data Structure /// /// This type is volatile and may change. pub type FnResolutionCache = BTreeMap>>; /// _(internals)_ A type that holds all the current states of the [`Engine`]. /// Exported under the `internals` feature only. /// /// # Volatile Data Structure /// /// This type is volatile and may change. #[derive(Debug, Clone, Default)] pub struct EvalState { /// Source of the current context. pub source: Option, /// Normally, access to variables are parsed with a relative offset into the [`Scope`] to avoid a lookup. /// In some situation, e.g. after running an `eval` statement, or after a custom syntax statement, /// subsequent offsets may become mis-aligned. /// When that happens, this flag is turned on to force a [`Scope`] search by name. pub always_search_scope: bool, /// Level of the current scope. The global (root) level is zero, a new block (or function call) /// is one level higher, and so on. pub scope_level: usize, /// Number of operations performed. pub num_operations: u64, /// Number of modules loaded. pub num_modules: usize, /// Stack of function resolution caches. fn_resolution_caches: StaticVec, /// Embedded module resolver. #[cfg(not(feature = "no_module"))] pub embedded_module_resolver: Option>, } impl EvalState { /// Create a new [`EvalState`]. #[inline(always)] #[must_use] pub fn new() -> Self { Self { source: None, always_search_scope: false, scope_level: 0, num_operations: 0, num_modules: 0, #[cfg(not(feature = "no_module"))] embedded_module_resolver: None, fn_resolution_caches: StaticVec::new(), } } /// Is the state currently at global (root) level? #[inline(always)] #[must_use] pub const fn is_global(&self) -> bool { self.scope_level == 0 } /// Get a mutable reference to the current function resolution cache. #[inline] #[must_use] pub fn fn_resolution_cache_mut(&mut self) -> &mut FnResolutionCache { if self.fn_resolution_caches.is_empty() { // Push a new function resolution cache if the stack is empty self.push_fn_resolution_cache(); } self.fn_resolution_caches .last_mut() .expect("at least one function resolution cache") } /// Push an empty function resolution cache onto the stack and make it current. #[allow(dead_code)] #[inline(always)] pub fn push_fn_resolution_cache(&mut self) { self.fn_resolution_caches.push(Default::default()); } /// Remove the current function resolution cache from the stack and make the last one current. /// /// # Panics /// /// Panics if there is no more function resolution cache in the stack. #[inline(always)] pub fn pop_fn_resolution_cache(&mut self) { self.fn_resolution_caches .pop() .expect("at least one function resolution cache"); } } /// _(internals)_ A type containing all the limits imposed by the [`Engine`]. /// Exported under the `internals` feature only. /// /// # Volatile Data Structure /// /// This type is volatile and may change. #[cfg(not(feature = "unchecked"))] #[derive(Debug, Clone, Eq, PartialEq, Hash)] pub struct Limits { /// Maximum levels of call-stack to prevent infinite recursion. /// /// Set to zero to effectively disable function calls. /// /// Not available under `no_function`. #[cfg(not(feature = "no_function"))] pub max_call_stack_depth: usize, /// Maximum depth of statements/expressions at global level. pub max_expr_depth: Option, /// Maximum depth of statements/expressions in functions. /// /// Not available under `no_function`. #[cfg(not(feature = "no_function"))] pub max_function_expr_depth: Option, /// Maximum number of operations allowed to run. pub max_operations: Option, /// Maximum number of [modules][Module] allowed to load. /// /// Set to zero to effectively disable loading any [module][Module]. /// /// Not available under `no_module`. #[cfg(not(feature = "no_module"))] pub max_modules: usize, /// Maximum length of a [string][ImmutableString]. pub max_string_size: Option, /// Maximum length of an [array][Array]. /// /// Not available under `no_index`. #[cfg(not(feature = "no_index"))] pub max_array_size: Option, /// Maximum number of properties in an [object map][Map]. /// /// Not available under `no_object`. #[cfg(not(feature = "no_object"))] pub max_map_size: Option, } #[cfg(not(feature = "unchecked"))] impl Default for Limits { fn default() -> Self { Self { #[cfg(not(feature = "no_function"))] max_call_stack_depth: MAX_CALL_STACK_DEPTH, max_expr_depth: NonZeroUsize::new(MAX_EXPR_DEPTH), #[cfg(not(feature = "no_function"))] max_function_expr_depth: NonZeroUsize::new(MAX_FUNCTION_EXPR_DEPTH), max_operations: None, #[cfg(not(feature = "no_module"))] max_modules: usize::MAX, max_string_size: None, #[cfg(not(feature = "no_index"))] max_array_size: None, #[cfg(not(feature = "no_object"))] max_map_size: None, } } } /// A type containing useful constants for the [`Engine`]. #[derive(Debug)] pub struct GlobalConstants { /// An empty [`ImmutableString`] for cloning purposes. pub(crate) empty_string: ImmutableString, /// Function call hash to FN_IDX_GET #[cfg(any(not(feature = "no_index"), not(feature = "no_object")))] pub(crate) fn_hash_idx_get: u64, /// Function call hash to FN_IDX_SET #[cfg(any(not(feature = "no_index"), not(feature = "no_object")))] pub(crate) fn_hash_idx_set: u64, } impl Default for GlobalConstants { fn default() -> Self { Self { empty_string: Default::default(), #[cfg(any(not(feature = "no_index"), not(feature = "no_object")))] fn_hash_idx_get: calc_fn_hash(FN_IDX_GET, 2), #[cfg(any(not(feature = "no_index"), not(feature = "no_object")))] fn_hash_idx_set: calc_fn_hash(FN_IDX_SET, 3), } } } /// Context of a script evaluation process. #[derive(Debug)] pub struct EvalContext<'a, 'x, 'px, 'm, 's, 'b, 't, 'pt> { pub(crate) engine: &'a Engine, pub(crate) scope: &'x mut Scope<'px>, pub(crate) mods: &'m mut Imports, pub(crate) state: &'s mut EvalState, pub(crate) lib: &'b [&'b Module], pub(crate) this_ptr: &'t mut Option<&'pt mut Dynamic>, pub(crate) level: usize, } impl<'x, 'px, 'pt> EvalContext<'_, 'x, 'px, '_, '_, '_, '_, 'pt> { /// The current [`Engine`]. #[inline(always)] #[must_use] pub const fn engine(&self) -> &Engine { self.engine } /// The current source. #[inline(always)] #[must_use] pub fn source(&self) -> Option<&str> { self.state.source.as_ref().map(|s| s.as_str()) } /// The current [`Scope`]. #[inline(always)] #[must_use] pub const fn scope(&self) -> &Scope<'px> { self.scope } /// Mutable reference to the current [`Scope`]. #[inline(always)] #[must_use] pub fn scope_mut(&mut self) -> &mut &'x mut Scope<'px> { &mut self.scope } /// Get an iterator over the current set of modules imported via `import` statements. #[cfg(not(feature = "no_module"))] #[inline(always)] pub fn iter_imports(&self) -> impl Iterator { self.mods.iter() } /// _(internals)_ The current set of modules imported via `import` statements. /// Exported under the `internals` feature only. #[cfg(feature = "internals")] #[cfg(not(feature = "no_module"))] #[inline(always)] #[must_use] pub const fn imports(&self) -> &Imports { self.mods } /// Get an iterator over the namespaces containing definition of all script-defined functions. #[inline(always)] pub fn iter_namespaces(&self) -> impl Iterator { self.lib.iter().cloned() } /// _(internals)_ The current set of namespaces containing definitions of all script-defined functions. /// Exported under the `internals` feature only. #[cfg(feature = "internals")] #[inline(always)] #[must_use] pub const fn namespaces(&self) -> &[&Module] { self.lib } /// The current bound `this` pointer, if any. #[inline(always)] #[must_use] pub fn this_ptr(&self) -> Option<&Dynamic> { self.this_ptr.as_ref().map(|v| &**v) } /// Mutable reference to the current bound `this` pointer, if any. #[inline(always)] #[must_use] pub fn this_ptr_mut(&mut self) -> Option<&mut &'pt mut Dynamic> { self.this_ptr.as_mut() } /// The current nesting level of function calls. #[inline(always)] #[must_use] pub const fn call_level(&self) -> usize { self.level } } /// Rhai main scripting engine. /// /// # Thread Safety /// /// [`Engine`] is re-entrant. /// /// Currently, [`Engine`] is neither [`Send`] nor [`Sync`]. /// Use the `sync` feature to make it [`Send`] `+` [`Sync`]. /// /// # Example /// /// ``` /// # fn main() -> Result<(), Box> { /// use rhai::Engine; /// /// let engine = Engine::new(); /// /// let result = engine.eval::("40 + 2")?; /// /// println!("Answer: {}", result); // prints 42 /// # Ok(()) /// # } /// ``` pub struct Engine { /// A collection of all modules loaded into the global namespace of the Engine. pub(crate) global_modules: StaticVec>, /// A collection of all sub-modules directly loaded into the Engine. pub(crate) global_sub_modules: BTreeMap>, /// A module resolution service. #[cfg(not(feature = "no_module"))] pub(crate) module_resolver: Option>, /// A map mapping type names to pretty-print names. pub(crate) type_names: BTreeMap>, /// Useful constants pub(crate) constants: GlobalConstants, /// A set of symbols to disable. pub(crate) disabled_symbols: BTreeSet, /// A map containing custom keywords and precedence to recognize. pub(crate) custom_keywords: BTreeMap>, /// Custom syntax. pub(crate) custom_syntax: BTreeMap>, /// Callback closure for resolving variable access. pub(crate) resolve_var: Option, /// Callback closure to remap tokens during parsing. pub(crate) token_mapper: Option>, /// Callback closure for implementing the `print` command. pub(crate) print: Option, /// Callback closure for implementing the `debug` command. pub(crate) debug: Option, /// Callback closure for progress reporting. #[cfg(not(feature = "unchecked"))] pub(crate) progress: Option, /// Optimize the AST after compilation. pub(crate) optimization_level: OptimizationLevel, /// Max limits. #[cfg(not(feature = "unchecked"))] pub(crate) limits: Limits, } impl fmt::Debug for Engine { #[inline(always)] fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { f.write_str("Engine") } } impl Default for Engine { #[inline(always)] fn default() -> Self { Self::new() } } /// Make getter function #[cfg(not(feature = "no_object"))] #[inline] #[must_use] pub fn make_getter(id: &str) -> String { format!("{}{}", FN_GET, id) } /// Make setter function #[cfg(not(feature = "no_object"))] #[inline] #[must_use] pub fn make_setter(id: &str) -> String { format!("{}{}", FN_SET, id) } /// Is this function an anonymous function? #[cfg(not(feature = "no_function"))] #[inline(always)] #[must_use] pub fn is_anonymous_fn(fn_name: &str) -> bool { fn_name.starts_with(FN_ANONYMOUS) } /// Print to `stdout` #[inline] #[allow(unused_variables)] fn print_to_stdout(s: &str) { #[cfg(not(feature = "no_std"))] #[cfg(not(any(target_arch = "wasm32", target_arch = "wasm64")))] println!("{}", s); } /// Debug to `stdout` #[inline] #[allow(unused_variables)] fn debug_to_stdout(s: &str, source: Option<&str>, pos: Position) { #[cfg(not(feature = "no_std"))] #[cfg(not(any(target_arch = "wasm32", target_arch = "wasm64")))] if let Some(source) = source { println!("{}{:?} | {}", source, pos, s); } else if pos.is_none() { println!("{}", s); } else { println!("{:?} | {}", pos, s); } } impl Engine { /// Create a new [`Engine`]. #[inline] #[must_use] pub fn new() -> Self { // Create the new scripting Engine let mut engine = Self::new_raw(); #[cfg(not(feature = "no_module"))] #[cfg(not(feature = "no_std"))] #[cfg(not(any(target_arch = "wasm32", target_arch = "wasm64")))] { engine.module_resolver = Some(Box::new(crate::module::resolvers::FileModuleResolver::new())); } // default print/debug implementations engine.print = Some(Box::new(print_to_stdout)); engine.debug = Some(Box::new(debug_to_stdout)); engine.register_global_module(StandardPackage::new().as_shared_module()); engine } /// Create a new [`Engine`] with minimal built-in functions. /// /// Use [`register_global_module`][Engine::register_global_module] to add packages of functions. #[inline] #[must_use] pub fn new_raw() -> Self { let mut engine = Self { global_modules: Default::default(), global_sub_modules: Default::default(), #[cfg(not(feature = "no_module"))] module_resolver: None, type_names: Default::default(), constants: Default::default(), disabled_symbols: Default::default(), custom_keywords: Default::default(), custom_syntax: Default::default(), resolve_var: None, token_mapper: None, print: None, debug: None, #[cfg(not(feature = "unchecked"))] progress: None, optimization_level: Default::default(), #[cfg(not(feature = "unchecked"))] limits: Default::default(), }; // Add the global namespace module let mut global_namespace = Module::new(); global_namespace.internal = true; engine.global_modules.push(global_namespace.into()); engine } /// Get an empty [`ImmutableString`]. /// /// [`Engine`] keeps a single instance of an empty [`ImmutableString`] and uses this to create /// shared instances for subsequent uses. This minimizes unnecessary allocations for empty strings. #[inline(always)] #[must_use] pub fn const_empty_string(&self) -> ImmutableString { self.constants.empty_string.clone() } /// Search for a module within an imports stack. #[inline] #[must_use] pub(crate) fn search_imports( &self, mods: &Imports, state: &mut EvalState, namespace: &NamespaceRef, ) -> Option> { let root = &namespace[0].name; // Qualified - check if the root module is directly indexed let index = if state.always_search_scope { None } else { namespace.index() }; if let Some(index) = index { let offset = mods.len() - index.get(); Some(mods.get(offset).expect("offset within range")) } else { mods.find(root) .map(|n| mods.get(n).expect("index is valid")) .or_else(|| self.global_sub_modules.get(root).cloned()) } } /// Search for a variable within the scope or within imports, /// depending on whether the variable name is namespace-qualified. pub(crate) fn search_namespace<'s>( &self, scope: &'s mut Scope, mods: &mut Imports, state: &mut EvalState, lib: &[&Module], this_ptr: &'s mut Option<&mut Dynamic>, expr: &Expr, ) -> Result<(Target<'s>, Position), Box> { match expr { Expr::Variable(Some(_), _, _) => { self.search_scope_only(scope, mods, state, lib, this_ptr, expr) } Expr::Variable(None, var_pos, v) => match v.as_ref() { // Normal variable access (_, None, _) => self.search_scope_only(scope, mods, state, lib, this_ptr, expr), // Qualified variable (_, Some((namespace, hash_var)), var_name) => { let module = self.search_imports(mods, state, namespace).ok_or_else(|| { EvalAltResult::ErrorModuleNotFound( namespace[0].name.to_string(), namespace[0].pos, ) })?; let target = module.get_qualified_var(*hash_var).map_err(|mut err| { match *err { EvalAltResult::ErrorVariableNotFound(ref mut err_name, _) => { *err_name = format!("{}{}", namespace, var_name); } _ => (), } err.fill_position(*var_pos) })?; // Module variables are constant let mut target = target.clone(); target.set_access_mode(AccessMode::ReadOnly); Ok((target.into(), *var_pos)) } }, _ => unreachable!("Expr::Variable expected, but gets {:?}", expr), } } /// Search for a variable within the scope /// /// # Panics /// /// Panics if `expr` is not [`Expr::Variable`]. pub(crate) fn search_scope_only<'s>( &self, scope: &'s mut Scope, mods: &mut Imports, state: &mut EvalState, lib: &[&Module], this_ptr: &'s mut Option<&mut Dynamic>, expr: &Expr, ) -> Result<(Target<'s>, Position), Box> { // Make sure that the pointer indirection is taken only when absolutely necessary. let (index, var_pos) = match expr { // Check if the variable is `this` Expr::Variable(None, pos, v) if v.0.is_none() && v.2 == KEYWORD_THIS => { return if let Some(val) = this_ptr { Ok(((*val).into(), *pos)) } else { EvalAltResult::ErrorUnboundThis(*pos).into() } } _ if state.always_search_scope => (0, expr.position()), Expr::Variable(Some(i), pos, _) => (i.get() as usize, *pos), Expr::Variable(None, pos, v) => (v.0.map(NonZeroUsize::get).unwrap_or(0), *pos), _ => unreachable!("Expr::Variable expected, but gets {:?}", expr), }; // Check the variable resolver, if any if let Some(ref resolve_var) = self.resolve_var { let context = EvalContext { engine: self, scope, mods, state, lib, this_ptr, level: 0, }; match resolve_var( expr.get_variable_name(true).expect("`expr` is `Variable`"), index, &context, ) { Ok(Some(mut result)) => { result.set_access_mode(AccessMode::ReadOnly); return Ok((result.into(), var_pos)); } Ok(None) => (), Err(err) => return Err(err.fill_position(var_pos)), } } let index = if index > 0 { scope.len() - index } else { // Find the variable in the scope let var_name = expr.get_variable_name(true).expect("`expr` is `Variable`"); scope .get_index(var_name) .ok_or_else(|| EvalAltResult::ErrorVariableNotFound(var_name.to_string(), var_pos))? .0 }; let val = scope.get_mut_by_index(index); Ok((val.into(), var_pos)) } /// Chain-evaluate a dot/index chain. /// [`Position`] in [`EvalAltResult`] is [`NONE`][Position::NONE] and must be set afterwards. #[cfg(any(not(feature = "no_index"), not(feature = "no_object")))] fn eval_dot_index_chain_helper( &self, mods: &mut Imports, state: &mut EvalState, lib: &[&Module], this_ptr: &mut Option<&mut Dynamic>, target: &mut Target, root: (&str, Position), rhs: &Expr, terminate_chaining: bool, idx_values: &mut StaticVec, chain_type: ChainType, level: usize, new_val: Option<((Dynamic, Position), (Option, Position))>, ) -> Result<(Dynamic, bool), Box> { let is_ref_mut = target.is_ref(); let _terminate_chaining = terminate_chaining; // Pop the last index value let idx_val = idx_values.pop().expect("index chain is never empty"); match chain_type { #[cfg(not(feature = "no_index"))] ChainType::Indexing => { let pos = rhs.position(); let idx_val = idx_val .into_index_value() .expect("`chain_type` is `ChainType::Index`"); match rhs { // xxx[idx].expr... | xxx[idx][expr]... Expr::Dot(x, term, x_pos) | Expr::Index(x, term, x_pos) if !_terminate_chaining => { let idx_pos = x.lhs.position(); let obj_ptr = &mut self.get_indexed_mut( mods, state, lib, target, idx_val, idx_pos, false, true, level, )?; let rhs_chain = match_chaining_type(rhs); self.eval_dot_index_chain_helper( mods, state, lib, this_ptr, obj_ptr, root, &x.rhs, *term, idx_values, rhs_chain, level, new_val, ) .map_err(|err| err.fill_position(*x_pos)) } // xxx[rhs] op= new_val _ if new_val.is_some() => { let ((new_val, new_pos), (op_info, op_pos)) = new_val.expect("`new_val` is `Some`"); let mut idx_val_for_setter = idx_val.clone(); let try_setter = match self.get_indexed_mut( mods, state, lib, target, idx_val, pos, true, false, level, ) { // Indexed value is a reference - update directly Ok(ref mut obj_ptr) => { self.eval_op_assignment( mods, state, lib, op_info, op_pos, obj_ptr, root, new_val, ) .map_err(|err| err.fill_position(new_pos))?; None } // Can't index - try to call an index setter #[cfg(not(feature = "no_index"))] Err(err) if matches!(*err, EvalAltResult::ErrorIndexingType(_, _)) => { Some(new_val) } // Any other error Err(err) => return Err(err), }; if let Some(mut new_val) = try_setter { // Try to call index setter let hash_set = FnCallHashes::from_native(self.constants.fn_hash_idx_set); let args = &mut [target, &mut idx_val_for_setter, &mut new_val]; let pos = Position::NONE; self.exec_fn_call( mods, state, lib, FN_IDX_SET, hash_set, args, is_ref_mut, true, pos, None, level, )?; } self.check_data_size(target.as_ref()) .map_err(|err| err.fill_position(root.1))?; Ok((Dynamic::UNIT, true)) } // xxx[rhs] _ => self .get_indexed_mut(mods, state, lib, target, idx_val, pos, false, true, level) .map(|v| (v.take_or_clone(), false)), } } #[cfg(not(feature = "no_object"))] ChainType::Dotting => { match rhs { // xxx.fn_name(arg_expr_list) Expr::FnCall(x, pos) if !x.is_qualified() && new_val.is_none() => { let FnCallExpr { name, hashes, .. } = x.as_ref(); let call_args = &mut idx_val .into_fn_call_args() .expect("`chain_type` is `ChainType::Dot` with `Expr::FnCallExpr`"); self.make_method_call( mods, state, lib, name, *hashes, target, call_args, *pos, level, ) } // xxx.fn_name(...) = ??? Expr::FnCall(_, _) if new_val.is_some() => { unreachable!("method call cannot be assigned to") } // xxx.module::fn_name(...) - syntax error Expr::FnCall(_, _) => { unreachable!("function call in dot chain should not be namespace-qualified") } // {xxx:map}.id op= ??? Expr::Property(x) if target.is::() && new_val.is_some() => { let (name, pos) = &x.2; let ((new_val, new_pos), (op_info, op_pos)) = new_val.expect("`new_val` is `Some`"); let index = name.into(); { let val_target = &mut self.get_indexed_mut( mods, state, lib, target, index, *pos, true, false, level, )?; self.eval_op_assignment( mods, state, lib, op_info, op_pos, val_target, root, new_val, ) .map_err(|err| err.fill_position(new_pos))?; } self.check_data_size(target.as_ref()) .map_err(|err| err.fill_position(root.1))?; Ok((Dynamic::UNIT, true)) } // {xxx:map}.id Expr::Property(x) if target.is::() => { let (name, pos) = &x.2; let index = name.into(); let val = self.get_indexed_mut( mods, state, lib, target, index, *pos, false, false, level, )?; Ok((val.take_or_clone(), false)) } // xxx.id op= ??? Expr::Property(x) if new_val.is_some() => { let ((getter, hash_get), (setter, hash_set), (name, pos)) = x.as_ref(); let ((mut new_val, new_pos), (op_info, op_pos)) = new_val.expect("`new_val` is `Some`"); if op_info.is_some() { let hash = FnCallHashes::from_native(*hash_get); let args = &mut [target.as_mut()]; let (mut orig_val, _) = self .exec_fn_call( mods, state, lib, getter, hash, args, is_ref_mut, true, *pos, None, level, ) .or_else(|err| match *err { // Try an indexer if property does not exist EvalAltResult::ErrorDotExpr(_, _) => { let prop = name.into(); self.get_indexed_mut( mods, state, lib, target, prop, *pos, false, true, level, ) .map(|v| (v.take_or_clone(), false)) .map_err( |idx_err| match *idx_err { EvalAltResult::ErrorIndexingType(_, _) => err, _ => idx_err, }, ) } _ => Err(err), })?; self.eval_op_assignment( mods, state, lib, op_info, op_pos, &mut (&mut orig_val).into(), root, new_val, ) .map_err(|err| err.fill_position(new_pos))?; self.check_data_size(target.as_ref()) .map_err(|err| err.fill_position(root.1))?; new_val = orig_val; } let hash = FnCallHashes::from_native(*hash_set); let args = &mut [target.as_mut(), &mut new_val]; self.exec_fn_call( mods, state, lib, setter, hash, args, is_ref_mut, true, *pos, None, level, ) .or_else(|err| match *err { // Try an indexer if property does not exist EvalAltResult::ErrorDotExpr(_, _) => { let args = &mut [target, &mut name.into(), &mut new_val]; let hash_set = FnCallHashes::from_native(self.constants.fn_hash_idx_set); let pos = Position::NONE; self.exec_fn_call( mods, state, lib, FN_IDX_SET, hash_set, args, is_ref_mut, true, pos, None, level, ) .map_err( |idx_err| match *idx_err { EvalAltResult::ErrorIndexingType(_, _) => err, _ => idx_err, }, ) } _ => Err(err), }) } // xxx.id Expr::Property(x) => { let ((getter, hash_get), _, (name, pos)) = x.as_ref(); let hash = FnCallHashes::from_native(*hash_get); let args = &mut [target.as_mut()]; self.exec_fn_call( mods, state, lib, getter, hash, args, is_ref_mut, true, *pos, None, level, ) .map_or_else( |err| match *err { // Try an indexer if property does not exist EvalAltResult::ErrorDotExpr(_, _) => { let prop = name.into(); self.get_indexed_mut( mods, state, lib, target, prop, *pos, false, true, level, ) .map(|v| (v.take_or_clone(), false)) .map_err(|idx_err| { match *idx_err { EvalAltResult::ErrorIndexingType(_, _) => err, _ => idx_err, } }) } _ => Err(err), }, // Assume getters are always pure |(v, _)| Ok((v, false)), ) } // {xxx:map}.sub_lhs[expr] | {xxx:map}.sub_lhs.expr Expr::Index(x, term, x_pos) | Expr::Dot(x, term, x_pos) if target.is::() => { let val_target = &mut match x.lhs { Expr::Property(ref p) => { let (name, pos) = &p.2; let index = name.into(); self.get_indexed_mut( mods, state, lib, target, index, *pos, false, true, level, )? } // {xxx:map}.fn_name(arg_expr_list)[expr] | {xxx:map}.fn_name(arg_expr_list).expr Expr::FnCall(ref x, pos) if !x.is_qualified() => { let FnCallExpr { name, hashes, .. } = x.as_ref(); let call_args = &mut idx_val.into_fn_call_args().expect( "`chain_type` is `ChainType::Dot` with `Expr::FnCallExpr`", ); let (val, _) = self.make_method_call( mods, state, lib, name, *hashes, target, call_args, pos, level, )?; val.into() } // {xxx:map}.module::fn_name(...) - syntax error Expr::FnCall(_, _) => unreachable!( "function call in dot chain should not be namespace-qualified" ), // Others - syntax error ref expr => unreachable!("invalid dot expression: {:?}", expr), }; let rhs_chain = match_chaining_type(rhs); self.eval_dot_index_chain_helper( mods, state, lib, this_ptr, val_target, root, &x.rhs, *term, idx_values, rhs_chain, level, new_val, ) .map_err(|err| err.fill_position(*x_pos)) } // xxx.sub_lhs[expr] | xxx.sub_lhs.expr Expr::Index(x, term, x_pos) | Expr::Dot(x, term, x_pos) => { match x.lhs { // xxx.prop[expr] | xxx.prop.expr Expr::Property(ref p) => { let ((getter, hash_get), (setter, hash_set), (name, pos)) = p.as_ref(); let rhs_chain = match_chaining_type(rhs); let hash_get = FnCallHashes::from_native(*hash_get); let hash_set = FnCallHashes::from_native(*hash_set); let mut arg_values = [target.as_mut(), &mut Default::default()]; let args = &mut arg_values[..1]; // Assume getters are always pure let (mut val, _) = self .exec_fn_call( mods, state, lib, getter, hash_get, args, is_ref_mut, true, *pos, None, level, ) .or_else(|err| match *err { // Try an indexer if property does not exist EvalAltResult::ErrorDotExpr(_, _) => { let prop = name.into(); self.get_indexed_mut( mods, state, lib, target, prop, *pos, false, true, level, ) .map(|v| (v.take_or_clone(), false)) .map_err( |idx_err| match *idx_err { EvalAltResult::ErrorIndexingType(_, _) => err, _ => idx_err, }, ) } _ => Err(err), })?; let val = &mut val; let (result, may_be_changed) = self .eval_dot_index_chain_helper( mods, state, lib, this_ptr, &mut val.into(), root, &x.rhs, *term, idx_values, rhs_chain, level, new_val, ) .map_err(|err| err.fill_position(*x_pos))?; // Feed the value back via a setter just in case it has been updated if may_be_changed { // Re-use args because the first &mut parameter will not be consumed let mut arg_values = [target.as_mut(), val]; let args = &mut arg_values; self.exec_fn_call( mods, state, lib, setter, hash_set, args, is_ref_mut, true, *pos, None, level, ) .or_else( |err| match *err { // Try an indexer if property does not exist EvalAltResult::ErrorDotExpr(_, _) => { let args = &mut [target.as_mut(), &mut name.into(), val]; let hash_set = FnCallHashes::from_native( self.constants.fn_hash_idx_set, ); self.exec_fn_call( mods, state, lib, FN_IDX_SET, hash_set, args, is_ref_mut, true, *pos, None, level, ) .or_else(|idx_err| match *idx_err { EvalAltResult::ErrorIndexingType(_, _) => { // If there is no setter, no need to feed it back because // the property is read-only Ok((Dynamic::UNIT, false)) } _ => Err(idx_err), }) } _ => Err(err), }, )?; self.check_data_size(target.as_ref()) .map_err(|err| err.fill_position(root.1))?; } Ok((result, may_be_changed)) } // xxx.fn_name(arg_expr_list)[expr] | xxx.fn_name(arg_expr_list).expr Expr::FnCall(ref f, pos) if !f.is_qualified() => { let FnCallExpr { name, hashes, .. } = f.as_ref(); let rhs_chain = match_chaining_type(rhs); let args = &mut idx_val.into_fn_call_args().expect( "`chain_type` is `ChainType::Dot` with `Expr::FnCallExpr`", ); let (mut val, _) = self.make_method_call( mods, state, lib, name, *hashes, target, args, pos, level, )?; let val = &mut val; let target = &mut val.into(); self.eval_dot_index_chain_helper( mods, state, lib, this_ptr, target, root, &x.rhs, *term, idx_values, rhs_chain, level, new_val, ) .map_err(|err| err.fill_position(pos)) } // xxx.module::fn_name(...) - syntax error Expr::FnCall(_, _) => unreachable!( "function call in dot chain should not be namespace-qualified" ), // Others - syntax error ref expr => unreachable!("invalid dot expression: {:?}", expr), } } // Syntax error _ => EvalAltResult::ErrorDotExpr("".into(), rhs.position()).into(), } } } } /// Evaluate a dot/index chain. #[cfg(any(not(feature = "no_index"), not(feature = "no_object")))] fn eval_dot_index_chain( &self, scope: &mut Scope, mods: &mut Imports, state: &mut EvalState, lib: &[&Module], this_ptr: &mut Option<&mut Dynamic>, expr: &Expr, level: usize, new_val: Option<((Dynamic, Position), (Option, Position))>, ) -> RhaiResult { let (crate::ast::BinaryExpr { lhs, rhs }, chain_type, term, op_pos) = match expr { #[cfg(not(feature = "no_index"))] Expr::Index(x, term, pos) => (x.as_ref(), ChainType::Indexing, *term, *pos), #[cfg(not(feature = "no_object"))] Expr::Dot(x, term, pos) => (x.as_ref(), ChainType::Dotting, *term, *pos), _ => unreachable!("index or dot chain expected, but gets {:?}", expr), }; let idx_values = &mut Default::default(); self.eval_dot_index_chain_arguments( scope, mods, state, lib, this_ptr, rhs, term, chain_type, idx_values, 0, level, )?; match lhs { // id.??? or id[???] Expr::Variable(_, var_pos, x) => { #[cfg(not(feature = "unchecked"))] self.inc_operations(state, *var_pos)?; let (mut target, _) = self.search_namespace(scope, mods, state, lib, this_ptr, lhs)?; let obj_ptr = &mut target; let root = (x.2.as_str(), *var_pos); self.eval_dot_index_chain_helper( mods, state, lib, &mut None, obj_ptr, root, rhs, term, idx_values, chain_type, level, new_val, ) .map(|(v, _)| v) .map_err(|err| err.fill_position(op_pos)) } // {expr}.??? = ??? or {expr}[???] = ??? _ if new_val.is_some() => unreachable!("cannot assign to an expression"), // {expr}.??? or {expr}[???] expr => { let value = self.eval_expr(scope, mods, state, lib, this_ptr, expr, level)?; let obj_ptr = &mut value.into(); let root = ("", expr.position()); self.eval_dot_index_chain_helper( mods, state, lib, this_ptr, obj_ptr, root, rhs, term, idx_values, chain_type, level, new_val, ) .map(|(v, _)| v) .map_err(|err| err.fill_position(op_pos)) } } } /// Evaluate a chain of indexes and store the results in a [`StaticVec`]. /// [`StaticVec`] is used to avoid an allocation in the overwhelming cases of /// just a few levels of indexing. #[cfg(any(not(feature = "no_index"), not(feature = "no_object")))] fn eval_dot_index_chain_arguments( &self, scope: &mut Scope, mods: &mut Imports, state: &mut EvalState, lib: &[&Module], this_ptr: &mut Option<&mut Dynamic>, expr: &Expr, terminate_chaining: bool, parent_chain_type: ChainType, idx_values: &mut StaticVec, size: usize, level: usize, ) -> Result<(), Box> { #[cfg(not(feature = "unchecked"))] self.inc_operations(state, expr.position())?; let _parent_chain_type = parent_chain_type; match expr { #[cfg(not(feature = "no_object"))] Expr::FnCall(x, _) if _parent_chain_type == ChainType::Dotting && !x.is_qualified() => { let crate::ast::FnCallExpr { args, constants, .. } = x.as_ref(); let mut arg_values = StaticVec::with_capacity(args.len()); let mut first_arg_pos = Position::NONE; for index in 0..args.len() { let (value, pos) = self.get_arg_value( scope, mods, state, lib, this_ptr, level, args, constants, index, )?; arg_values.push(value.flatten()); if index == 0 { first_arg_pos = pos } } idx_values.push((arg_values, first_arg_pos).into()); } #[cfg(not(feature = "no_object"))] Expr::FnCall(_, _) if _parent_chain_type == ChainType::Dotting => { unreachable!("function call in dot chain should not be namespace-qualified") } #[cfg(not(feature = "no_object"))] Expr::Property(x) if _parent_chain_type == ChainType::Dotting => { idx_values.push(ChainArgument::Property((x.2).1)) } Expr::Property(_) => unreachable!("unexpected Expr::Property for indexing"), Expr::Index(x, term, _) | Expr::Dot(x, term, _) if !terminate_chaining => { let crate::ast::BinaryExpr { lhs, rhs, .. } = x.as_ref(); // Evaluate in left-to-right order let lhs_val = match lhs { #[cfg(not(feature = "no_object"))] Expr::Property(x) if _parent_chain_type == ChainType::Dotting => { ChainArgument::Property((x.2).1) } Expr::Property(_) => unreachable!("unexpected Expr::Property for indexing"), #[cfg(not(feature = "no_object"))] Expr::FnCall(x, _) if _parent_chain_type == ChainType::Dotting && !x.is_qualified() => { let crate::ast::FnCallExpr { args, constants, .. } = x.as_ref(); let mut arg_values = StaticVec::with_capacity(args.len()); let mut first_arg_pos = Position::NONE; for index in 0..args.len() { let (value, pos) = self.get_arg_value( scope, mods, state, lib, this_ptr, level, args, constants, index, )?; arg_values.push(value.flatten()); if index == 0 { first_arg_pos = pos; } } (arg_values, first_arg_pos).into() } #[cfg(not(feature = "no_object"))] Expr::FnCall(_, _) if _parent_chain_type == ChainType::Dotting => { unreachable!("function call in dot chain should not be namespace-qualified") } #[cfg(not(feature = "no_object"))] expr if _parent_chain_type == ChainType::Dotting => { unreachable!("invalid dot expression: {:?}", expr); } #[cfg(not(feature = "no_index"))] _ if _parent_chain_type == ChainType::Indexing => self .eval_expr(scope, mods, state, lib, this_ptr, lhs, level) .map(|v| (v.flatten(), lhs.position()).into())?, expr => unreachable!("unknown chained expression: {:?}", expr), }; // Push in reverse order let chain_type = match_chaining_type(expr); self.eval_dot_index_chain_arguments( scope, mods, state, lib, this_ptr, rhs, *term, chain_type, idx_values, size, level, )?; idx_values.push(lhs_val); } #[cfg(not(feature = "no_object"))] _ if _parent_chain_type == ChainType::Dotting => { unreachable!("invalid dot expression: {:?}", expr); } #[cfg(not(feature = "no_index"))] _ if _parent_chain_type == ChainType::Indexing => idx_values.push( self.eval_expr(scope, mods, state, lib, this_ptr, expr, level) .map(|v| (v.flatten(), expr.position()).into())?, ), _ => unreachable!("unknown chained expression: {:?}", expr), } Ok(()) } /// Get the value at the indexed position of a base type. /// [`Position`] in [`EvalAltResult`] may be [`NONE`][Position::NONE] and should be set afterwards. #[cfg(any(not(feature = "no_index"), not(feature = "no_object")))] fn get_indexed_mut<'t>( &self, mods: &mut Imports, state: &mut EvalState, lib: &[&Module], target: &'t mut Dynamic, idx: Dynamic, idx_pos: Position, add_if_not_found: bool, use_indexers: bool, level: usize, ) -> Result, Box> { #[cfg(not(feature = "unchecked"))] self.inc_operations(state, Position::NONE)?; let mut idx = idx; let _add_if_not_found = add_if_not_found; match target { #[cfg(not(feature = "no_index"))] Dynamic(Union::Array(arr, _, _)) => { // val_array[idx] let index = idx .as_int() .map_err(|typ| self.make_type_mismatch_err::(typ, idx_pos))?; let arr_len = arr.len(); #[cfg(not(feature = "unchecked"))] let arr_idx = if index < 0 { // Count from end if negative arr_len - index .checked_abs() .ok_or_else(|| { Box::new(EvalAltResult::ErrorArrayBounds(arr_len, index, idx_pos)) }) .and_then(|n| { if n as usize > arr_len { Err(EvalAltResult::ErrorArrayBounds(arr_len, index, idx_pos) .into()) } else { Ok(n as usize) } })? } else { index as usize }; #[cfg(feature = "unchecked")] let arr_idx = if index < 0 { // Count from end if negative arr_len - index.abs() as usize } else { index as usize }; arr.get_mut(arr_idx) .map(Target::from) .ok_or_else(|| EvalAltResult::ErrorArrayBounds(arr_len, index, idx_pos).into()) } #[cfg(not(feature = "no_object"))] Dynamic(Union::Map(map, _, _)) => { // val_map[idx] let index = idx.read_lock::().ok_or_else(|| { self.make_type_mismatch_err::(idx.type_name(), idx_pos) })?; if _add_if_not_found && !map.contains_key(index.as_str()) { map.insert(index.clone().into(), Default::default()); } Ok(map .get_mut(index.as_str()) .map(Target::from) .unwrap_or_else(|| Target::from(Dynamic::UNIT))) } #[cfg(not(feature = "no_index"))] Dynamic(Union::Int(value, _, _)) => { // val_int[idx] let index = idx .as_int() .map_err(|typ| self.make_type_mismatch_err::(typ, idx_pos))?; let bits = std::mem::size_of_val(value) * 8; let (bit_value, offset) = if index >= 0 { let offset = index as usize; ( if offset >= bits { return EvalAltResult::ErrorBitFieldBounds(bits, index, idx_pos).into(); } else { (*value & (1 << offset)) != 0 }, offset, ) } else if let Some(abs_index) = index.checked_abs() { let offset = abs_index as usize; ( // Count from end if negative if offset > bits { return EvalAltResult::ErrorBitFieldBounds(bits, index, idx_pos).into(); } else { (*value & (1 << (bits - offset))) != 0 }, offset, ) } else { return EvalAltResult::ErrorBitFieldBounds(bits, index, idx_pos).into(); }; Ok(Target::BitField(target, offset, bit_value.into())) } #[cfg(not(feature = "no_index"))] Dynamic(Union::Str(s, _, _)) => { // val_string[idx] let index = idx .as_int() .map_err(|typ| self.make_type_mismatch_err::(typ, idx_pos))?; let (ch, offset) = if index >= 0 { let offset = index as usize; ( s.chars().nth(offset).ok_or_else(|| { let chars_len = s.chars().count(); EvalAltResult::ErrorStringBounds(chars_len, index, idx_pos) })?, offset, ) } else if let Some(abs_index) = index.checked_abs() { let offset = abs_index as usize; ( // Count from end if negative s.chars().rev().nth(offset - 1).ok_or_else(|| { let chars_len = s.chars().count(); EvalAltResult::ErrorStringBounds(chars_len, index, idx_pos) })?, offset, ) } else { let chars_len = s.chars().count(); return EvalAltResult::ErrorStringBounds(chars_len, index, idx_pos).into(); }; Ok(Target::StringChar(target, offset, ch.into())) } _ if use_indexers => { let args = &mut [target, &mut idx]; let hash_get = FnCallHashes::from_native(self.constants.fn_hash_idx_get); let idx_pos = Position::NONE; self.exec_fn_call( mods, state, lib, FN_IDX_GET, hash_get, args, true, true, idx_pos, None, level, ) .map(|(v, _)| v.into()) } _ => EvalAltResult::ErrorIndexingType( format!( "{} [{}]", self.map_type_name(target.type_name()), self.map_type_name(idx.type_name()) ), Position::NONE, ) .into(), } } /// Evaluate an expression. pub(crate) fn eval_expr( &self, scope: &mut Scope, mods: &mut Imports, state: &mut EvalState, lib: &[&Module], this_ptr: &mut Option<&mut Dynamic>, expr: &Expr, level: usize, ) -> RhaiResult { #[cfg(not(feature = "unchecked"))] self.inc_operations(state, expr.position())?; let result = match expr { Expr::DynamicConstant(x, _) => Ok(x.as_ref().clone()), Expr::IntegerConstant(x, _) => Ok((*x).into()), #[cfg(not(feature = "no_float"))] Expr::FloatConstant(x, _) => Ok((*x).into()), Expr::StringConstant(x, _) => Ok(x.clone().into()), Expr::CharConstant(x, _) => Ok((*x).into()), Expr::Variable(None, var_pos, x) if x.0.is_none() && x.2 == KEYWORD_THIS => this_ptr .as_deref() .cloned() .ok_or_else(|| EvalAltResult::ErrorUnboundThis(*var_pos).into()), Expr::Variable(_, _, _) => self .search_namespace(scope, mods, state, lib, this_ptr, expr) .map(|(val, _)| val.take_or_clone()), // Statement block Expr::Stmt(x) if x.is_empty() => Ok(Dynamic::UNIT), Expr::Stmt(x) => { self.eval_stmt_block(scope, mods, state, lib, this_ptr, x, true, level) } // lhs[idx_expr] #[cfg(not(feature = "no_index"))] Expr::Index(_, _, _) => { self.eval_dot_index_chain(scope, mods, state, lib, this_ptr, expr, level, None) } // lhs.dot_rhs #[cfg(not(feature = "no_object"))] Expr::Dot(_, _, _) => { self.eval_dot_index_chain(scope, mods, state, lib, this_ptr, expr, level, None) } // `... ${...} ...` Expr::InterpolatedString(x, pos) => { let mut pos = *pos; let mut result: Dynamic = self.const_empty_string().into(); for expr in x.iter() { let item = self.eval_expr(scope, mods, state, lib, this_ptr, expr, level)?; self.eval_op_assignment( mods, state, lib, Some(OpAssignment::new(TOKEN_OP_CONCAT)), pos, &mut (&mut result).into(), ("", Position::NONE), item, ) .map_err(|err| err.fill_position(expr.position()))?; pos = expr.position(); self.check_data_size(&result) .map_err(|err| err.fill_position(pos))?; } assert!( result.is::(), "interpolated string must be a string" ); Ok(result) } #[cfg(not(feature = "no_index"))] Expr::Array(x, _) => { let mut arr = Array::with_capacity(x.len()); for item in x.as_ref() { arr.push( self.eval_expr(scope, mods, state, lib, this_ptr, item, level)? .flatten(), ); } Ok(arr.into()) } #[cfg(not(feature = "no_object"))] Expr::Map(x, _) => { let mut map = x.1.clone(); for (Ident { name: key, .. }, expr) in &x.0 { let value_ref = map .get_mut(key.as_str()) .expect("template contains all keys"); *value_ref = self .eval_expr(scope, mods, state, lib, this_ptr, expr, level)? .flatten(); } Ok(map.into()) } // Namespace-qualified function call Expr::FnCall(x, pos) if x.is_qualified() => { let FnCallExpr { name, namespace, hashes, args, constants, .. } = x.as_ref(); let namespace = namespace.as_ref().expect("qualified function call"); let hash = hashes.native; self.make_qualified_function_call( scope, mods, state, lib, this_ptr, namespace, name, args, constants, hash, *pos, level, ) } // Normal function call Expr::FnCall(x, pos) => { let FnCallExpr { name, capture, hashes, args, constants, .. } = x.as_ref(); self.make_function_call( scope, mods, state, lib, this_ptr, name, args, constants, *hashes, *pos, *capture, level, ) } Expr::And(x, _) => { Ok((self .eval_expr(scope, mods, state, lib, this_ptr, &x.lhs, level)? .as_bool() .map_err(|typ| self.make_type_mismatch_err::(typ, x.lhs.position()))? && // Short-circuit using && self .eval_expr(scope, mods, state, lib, this_ptr, &x.rhs, level)? .as_bool() .map_err(|typ| self.make_type_mismatch_err::(typ, x.rhs.position()))?) .into()) } Expr::Or(x, _) => { Ok((self .eval_expr(scope, mods, state, lib, this_ptr, &x.lhs, level)? .as_bool() .map_err(|typ| self.make_type_mismatch_err::(typ, x.lhs.position()))? || // Short-circuit using || self .eval_expr(scope, mods, state, lib, this_ptr, &x.rhs, level)? .as_bool() .map_err(|typ| self.make_type_mismatch_err::(typ, x.rhs.position()))?) .into()) } Expr::BoolConstant(x, _) => Ok((*x).into()), Expr::Unit(_) => Ok(Dynamic::UNIT), Expr::Custom(custom, _) => { let expressions: StaticVec<_> = custom.keywords.iter().map(Into::into).collect(); let key_token = custom .tokens .first() .expect("custom syntax stream contains at least one token"); let custom_def = self .custom_syntax .get(key_token) .expect("custom syntax leading token matches with definition"); let mut context = EvalContext { engine: self, scope, mods, state, lib, this_ptr, level, }; (custom_def.func)(&mut context, &expressions) } _ => unreachable!("expression cannot be evaluated: {:?}", expr), }; self.check_return_value(result) .map_err(|err| err.fill_position(expr.position())) } /// Evaluate a statements block. pub(crate) fn eval_stmt_block( &self, scope: &mut Scope, mods: &mut Imports, state: &mut EvalState, lib: &[&Module], this_ptr: &mut Option<&mut Dynamic>, statements: &[Stmt], restore_prev_state: bool, level: usize, ) -> RhaiResult { if statements.is_empty() { return Ok(Dynamic::UNIT); } let mut _extra_fn_resolution_cache = false; let prev_always_search_scope = state.always_search_scope; let prev_scope_len = scope.len(); let prev_mods_len = mods.len(); if restore_prev_state { state.scope_level += 1; } let result = statements.iter().try_fold(Dynamic::UNIT, |_, stmt| { let _mods_len = mods.len(); let r = self.eval_stmt(scope, mods, state, lib, this_ptr, stmt, level)?; #[cfg(not(feature = "no_module"))] if matches!(stmt, Stmt::Import(_, _, _)) { // Get the extra modules - see if any functions are marked global. // Without global functions, the extra modules never affect function resolution. if mods .scan_raw() .skip(_mods_len) .any(|(_, m)| m.contains_indexed_global_functions()) { if _extra_fn_resolution_cache { // When new module is imported with global functions and there is already // a new cache, clear it - notice that this is expensive as all function // resolutions must start again state.fn_resolution_cache_mut().clear(); } else if restore_prev_state { // When new module is imported with global functions, push a new cache state.push_fn_resolution_cache(); _extra_fn_resolution_cache = true; } else { // When the block is to be evaluated in-place, just clear the current cache state.fn_resolution_cache_mut().clear(); } } } Ok(r) }); if _extra_fn_resolution_cache { // If imports list is modified, pop the functions lookup cache state.pop_fn_resolution_cache(); } if restore_prev_state { scope.rewind(prev_scope_len); mods.truncate(prev_mods_len); state.scope_level -= 1; // The impact of new local variables goes away at the end of a block // because any new variables introduced will go out of scope state.always_search_scope = prev_always_search_scope; } result } /// Evaluate an op-assignment statement. /// [`Position`] in [`EvalAltResult`] is [`NONE`][Position::NONE] and should be set afterwards. pub(crate) fn eval_op_assignment( &self, mods: &mut Imports, state: &mut EvalState, lib: &[&Module], op_info: Option, op_pos: Position, target: &mut Target, root: (&str, Position), new_val: Dynamic, ) -> Result<(), Box> { if target.is_read_only() { // Assignment to constant variable return EvalAltResult::ErrorAssignmentToConstant(root.0.to_string(), root.1).into(); } let mut new_val = new_val; if let Some(OpAssignment { hash_op_assign, hash_op, op, }) = op_info { { let mut lock_guard; let lhs_ptr_inner; #[cfg(not(feature = "no_closure"))] let target_is_shared = target.is_shared(); #[cfg(feature = "no_closure")] let target_is_shared = false; if target_is_shared { lock_guard = target.write_lock::().expect("cast to `Dynamic`"); lhs_ptr_inner = &mut *lock_guard; } else { lhs_ptr_inner = &mut *target; } let hash = hash_op_assign; let args = &mut [lhs_ptr_inner, &mut new_val]; match self.call_native_fn(mods, state, lib, op, hash, args, true, true, op_pos) { Err(err) if matches!(err.as_ref(), EvalAltResult::ErrorFunctionNotFound(f, _) if f.starts_with(op)) => { // Expand to `var = var op rhs` let op = &op[..op.len() - 1]; // extract operator without = // Run function let (value, _) = self.call_native_fn( mods, state, lib, op, hash_op, args, true, false, op_pos, )?; *args[0] = value.flatten(); } err => return err.map(|_| ()), } } } else { // Normal assignment *target.as_mut() = new_val; } target.propagate_changed_value() } /// Evaluate a statement. /// /// # Safety /// /// This method uses some unsafe code, mainly for avoiding cloning of local variable names via /// direct lifetime casting. pub(crate) fn eval_stmt( &self, scope: &mut Scope, mods: &mut Imports, state: &mut EvalState, lib: &[&Module], this_ptr: &mut Option<&mut Dynamic>, stmt: &Stmt, level: usize, ) -> RhaiResult { #[cfg(not(feature = "unchecked"))] self.inc_operations(state, stmt.position())?; let result = match stmt { // No-op Stmt::Noop(_) => Ok(Dynamic::UNIT), // Expression as statement Stmt::Expr(expr) => Ok(self .eval_expr(scope, mods, state, lib, this_ptr, expr, level)? .flatten()), // var op= rhs Stmt::Assignment(x, op_pos) if x.0.is_variable_access(false) => { let (lhs_expr, op_info, rhs_expr) = x.as_ref(); let rhs_val = self .eval_expr(scope, mods, state, lib, this_ptr, rhs_expr, level)? .flatten(); let (mut lhs_ptr, pos) = self.search_namespace(scope, mods, state, lib, this_ptr, lhs_expr)?; let var_name = lhs_expr .get_variable_name(false) .expect("`lhs_ptr` is `Variable`"); if !lhs_ptr.is_ref() { return EvalAltResult::ErrorAssignmentToConstant(var_name.to_string(), pos) .into(); } #[cfg(not(feature = "unchecked"))] self.inc_operations(state, pos)?; self.eval_op_assignment( mods, state, lib, *op_info, *op_pos, &mut lhs_ptr, (var_name, pos), rhs_val, ) .map_err(|err| err.fill_position(rhs_expr.position()))?; if op_info.is_some() { self.check_data_size(lhs_ptr.as_ref()) .map_err(|err| err.fill_position(lhs_expr.position()))?; } Ok(Dynamic::UNIT) } // lhs op= rhs Stmt::Assignment(x, op_pos) => { let (lhs_expr, op_info, rhs_expr) = x.as_ref(); let rhs_val = self .eval_expr(scope, mods, state, lib, this_ptr, rhs_expr, level)? .flatten(); let _new_val = Some(((rhs_val, rhs_expr.position()), (*op_info, *op_pos))); // Must be either `var[index] op= val` or `var.prop op= val` match lhs_expr { // name op= rhs (handled above) Expr::Variable(_, _, _) => { unreachable!("Expr::Variable case should already been handled") } // idx_lhs[idx_expr] op= rhs #[cfg(not(feature = "no_index"))] Expr::Index(_, _, _) => { self.eval_dot_index_chain( scope, mods, state, lib, this_ptr, lhs_expr, level, _new_val, )?; Ok(Dynamic::UNIT) } // dot_lhs.dot_rhs op= rhs #[cfg(not(feature = "no_object"))] Expr::Dot(_, _, _) => { self.eval_dot_index_chain( scope, mods, state, lib, this_ptr, lhs_expr, level, _new_val, )?; Ok(Dynamic::UNIT) } _ => unreachable!("cannot assign to expression: {:?}", lhs_expr), } } // Block scope Stmt::Block(statements, _) if statements.is_empty() => Ok(Dynamic::UNIT), Stmt::Block(statements, _) => { self.eval_stmt_block(scope, mods, state, lib, this_ptr, statements, true, level) } // If statement Stmt::If(expr, x, _) => { let guard_val = self .eval_expr(scope, mods, state, lib, this_ptr, expr, level)? .as_bool() .map_err(|typ| self.make_type_mismatch_err::(typ, expr.position()))?; if guard_val { if !x.0.is_empty() { self.eval_stmt_block(scope, mods, state, lib, this_ptr, &x.0, true, level) } else { Ok(Dynamic::UNIT) } } else { if !x.1.is_empty() { self.eval_stmt_block(scope, mods, state, lib, this_ptr, &x.1, true, level) } else { Ok(Dynamic::UNIT) } } } // Switch statement Stmt::Switch(match_expr, x, _) => { let (table, def_stmt) = x.as_ref(); let value = self.eval_expr(scope, mods, state, lib, this_ptr, match_expr, level)?; if value.is_hashable() { let hasher = &mut get_hasher(); value.hash(hasher); let hash = hasher.finish(); table.get(&hash).and_then(|t| { if let Some(condition) = &t.0 { match self .eval_expr(scope, mods, state, lib, this_ptr, &condition, level) .and_then(|v| { v.as_bool().map_err(|typ| { self.make_type_mismatch_err::( typ, condition.position(), ) }) }) { Ok(true) => (), Ok(false) => return None, Err(err) => return Some(Err(err)), } } let statements = &t.1; Some(if !statements.is_empty() { self.eval_stmt_block( scope, mods, state, lib, this_ptr, statements, true, level, ) } else { Ok(Dynamic::UNIT) }) }) } else { // Non-hashable values never match any specific clause None } .unwrap_or_else(|| { // Default match clause if !def_stmt.is_empty() { self.eval_stmt_block( scope, mods, state, lib, this_ptr, def_stmt, true, level, ) } else { Ok(Dynamic::UNIT) } }) } // Loop Stmt::While(Expr::Unit(_), body, _) => loop { if !body.is_empty() { match self.eval_stmt_block(scope, mods, state, lib, this_ptr, body, true, level) { Ok(_) => (), Err(err) => match *err { EvalAltResult::LoopBreak(false, _) => (), EvalAltResult::LoopBreak(true, _) => return Ok(Dynamic::UNIT), _ => return Err(err), }, } } else { #[cfg(not(feature = "unchecked"))] self.inc_operations(state, body.position())?; } }, // While loop Stmt::While(expr, body, _) => loop { let condition = self .eval_expr(scope, mods, state, lib, this_ptr, expr, level)? .as_bool() .map_err(|typ| self.make_type_mismatch_err::(typ, expr.position()))?; if !condition { return Ok(Dynamic::UNIT); } if !body.is_empty() { match self.eval_stmt_block(scope, mods, state, lib, this_ptr, body, true, level) { Ok(_) => (), Err(err) => match *err { EvalAltResult::LoopBreak(false, _) => (), EvalAltResult::LoopBreak(true, _) => return Ok(Dynamic::UNIT), _ => return Err(err), }, } } }, // Do loop Stmt::Do(body, expr, options, _) => loop { let is_while = !options.contains(AST_OPTION_NEGATED); if !body.is_empty() { match self.eval_stmt_block(scope, mods, state, lib, this_ptr, body, true, level) { Ok(_) => (), Err(err) => match *err { EvalAltResult::LoopBreak(false, _) => continue, EvalAltResult::LoopBreak(true, _) => return Ok(Dynamic::UNIT), _ => return Err(err), }, } } let condition = self .eval_expr(scope, mods, state, lib, this_ptr, expr, level)? .as_bool() .map_err(|typ| self.make_type_mismatch_err::(typ, expr.position()))?; if condition ^ is_while { return Ok(Dynamic::UNIT); } }, // For loop Stmt::For(expr, x, _) => { let (Ident { name, .. }, counter, statements) = x.as_ref(); let iter_obj = self .eval_expr(scope, mods, state, lib, this_ptr, expr, level)? .flatten(); let iter_type = iter_obj.type_id(); // lib should only contain scripts, so technically they cannot have iterators // Search order: // 1) Global namespace - functions registered via Engine::register_XXX // 2) Global modules - packages // 3) Imported modules - functions marked with global namespace // 4) Global sub-modules - functions marked with global namespace let func = self .global_modules .iter() .find_map(|m| m.get_iter(iter_type)) .or_else(|| mods.get_iter(iter_type)) .or_else(|| { self.global_sub_modules .values() .find_map(|m| m.get_qualified_iter(iter_type)) }); if let Some(func) = func { // Add the loop variables let orig_scope_len = scope.len(); let counter_index = if let Some(Ident { name, .. }) = counter { scope.push(unsafe_cast_var_name_to_lifetime(name), 0 as INT); Some(scope.len() - 1) } else { None }; scope.push(unsafe_cast_var_name_to_lifetime(name), ()); let index = scope.len() - 1; state.scope_level += 1; for (x, iter_value) in func(iter_obj).enumerate() { // Increment counter if let Some(c) = counter_index { #[cfg(not(feature = "unchecked"))] if x > INT::MAX as usize { return EvalAltResult::ErrorArithmetic( format!("for-loop counter overflow: {}", x), counter.as_ref().expect("`counter` is `Some`").pos, ) .into(); } let mut counter_var = scope .get_mut_by_index(c) .write_lock::() .expect("counter holds `INT`"); *counter_var = x as INT; } let loop_var = scope.get_mut_by_index(index); let value = iter_value.flatten(); #[cfg(not(feature = "no_closure"))] let loop_var_is_shared = loop_var.is_shared(); #[cfg(feature = "no_closure")] let loop_var_is_shared = false; if loop_var_is_shared { let mut value_ref = loop_var.write_lock().expect("cast to `Dynamic`"); *value_ref = value; } else { *loop_var = value; } #[cfg(not(feature = "unchecked"))] self.inc_operations(state, statements.position())?; if statements.is_empty() { continue; } let result = self.eval_stmt_block( scope, mods, state, lib, this_ptr, statements, true, level, ); match result { Ok(_) => (), Err(err) => match *err { EvalAltResult::LoopBreak(false, _) => (), EvalAltResult::LoopBreak(true, _) => break, _ => return Err(err), }, } } state.scope_level -= 1; scope.rewind(orig_scope_len); Ok(Dynamic::UNIT) } else { EvalAltResult::ErrorFor(expr.position()).into() } } // Continue/Break statement Stmt::BreakLoop(options, pos) => { EvalAltResult::LoopBreak(options.contains(AST_OPTION_BREAK_OUT), *pos).into() } // Namespace-qualified function call Stmt::FnCall(x, pos) if x.is_qualified() => { let FnCallExpr { name, namespace, hashes, args, constants, .. } = x.as_ref(); let namespace = namespace.as_ref().expect("qualified function call"); let hash = hashes.native; self.make_qualified_function_call( scope, mods, state, lib, this_ptr, namespace, name, args, constants, hash, *pos, level, ) } // Normal function call Stmt::FnCall(x, pos) => { let FnCallExpr { name, capture, hashes, args, constants, .. } = x.as_ref(); self.make_function_call( scope, mods, state, lib, this_ptr, name, args, constants, *hashes, *pos, *capture, level, ) } // Try/Catch statement Stmt::TryCatch(x, _) => { let (try_stmt, err_var, catch_stmt) = x.as_ref(); let result = self .eval_stmt_block(scope, mods, state, lib, this_ptr, try_stmt, true, level) .map(|_| Dynamic::UNIT); match result { Ok(_) => result, Err(err) if err.is_pseudo_error() => Err(err), Err(err) if !err.is_catchable() => Err(err), Err(mut err) => { let err_value = match *err { EvalAltResult::ErrorRuntime(ref x, _) => x.clone(), #[cfg(feature = "no_object")] _ => { err.take_position(); err.to_string().into() } #[cfg(not(feature = "no_object"))] _ => { let mut err_map = Map::new(); let err_pos = err.take_position(); err_map.insert("message".into(), err.to_string().into()); if let Some(ref source) = state.source { err_map.insert("source".into(), source.as_str().into()); } if err_pos.is_none() { // No position info } else { let line = err_pos .line() .expect("non-NONE `Position` has line number") as INT; let position = if err_pos.is_beginning_of_line() { 0 } else { err_pos .position() .expect("non-NONE `Position` has character position") } as INT; err_map.insert("line".into(), line.into()); err_map.insert("position".into(), position.into()); } err.dump_fields(&mut err_map); err_map.into() } }; let orig_scope_len = scope.len(); state.scope_level += 1; err_var.as_ref().map(|Ident { name, .. }| { scope.push(unsafe_cast_var_name_to_lifetime(name), err_value) }); let result = self.eval_stmt_block( scope, mods, state, lib, this_ptr, catch_stmt, true, level, ); state.scope_level -= 1; scope.rewind(orig_scope_len); match result { Ok(_) => Ok(Dynamic::UNIT), Err(result_err) => match *result_err { // Re-throw exception EvalAltResult::ErrorRuntime(Dynamic(Union::Unit(_, _, _)), pos) => { err.set_position(pos); Err(err) } _ => Err(result_err), }, } } } } // Throw value Stmt::Return(options, Some(expr), pos) if options.contains(AST_OPTION_BREAK_OUT) => { EvalAltResult::ErrorRuntime( self.eval_expr(scope, mods, state, lib, this_ptr, expr, level)? .flatten(), *pos, ) .into() } // Empty throw Stmt::Return(options, None, pos) if options.contains(AST_OPTION_BREAK_OUT) => { EvalAltResult::ErrorRuntime(Dynamic::UNIT, *pos).into() } // Return value Stmt::Return(_, Some(expr), pos) => EvalAltResult::Return( self.eval_expr(scope, mods, state, lib, this_ptr, expr, level)? .flatten(), *pos, ) .into(), // Empty return Stmt::Return(_, None, pos) => EvalAltResult::Return(Dynamic::UNIT, *pos).into(), // Let/const statement Stmt::Var(expr, x, options, _) => { let name = &x.name; let entry_type = if options.contains(AST_OPTION_CONSTANT) { AccessMode::ReadOnly } else { AccessMode::ReadWrite }; let export = options.contains(AST_OPTION_PUBLIC); let value = self .eval_expr(scope, mods, state, lib, this_ptr, expr, level)? .flatten(); let (var_name, _alias): (Cow<'_, str>, _) = if state.is_global() { #[cfg(not(feature = "no_function"))] if entry_type == AccessMode::ReadOnly && lib.iter().any(|&m| !m.is_empty()) { let global = if let Some(index) = mods.find(KEYWORD_GLOBAL) { match mods.get_mut(index).expect("index is valid") { m if m.internal => Some(m), _ => None, } } else { // Create automatic global module let mut global = Module::new(); global.internal = true; mods.push(KEYWORD_GLOBAL, global); Some(mods.get_mut(mods.len() - 1).expect("global module exists")) }; if let Some(global) = global { Shared::get_mut(global) .expect("global module is not shared") .set_var(name.clone(), value.clone()); } } ( name.to_string().into(), if export { Some(name.clone()) } else { None }, ) } else if export { unreachable!("exported variable not on global level"); } else { (unsafe_cast_var_name_to_lifetime(name).into(), None) }; scope.push_dynamic_value(var_name, entry_type, value); #[cfg(not(feature = "no_module"))] _alias.map(|alias| scope.add_entry_alias(scope.len() - 1, alias)); Ok(Dynamic::UNIT) } // Import statement #[cfg(not(feature = "no_module"))] Stmt::Import(expr, export, _pos) => { // Guard against too many modules #[cfg(not(feature = "unchecked"))] if state.num_modules >= self.max_modules() { return EvalAltResult::ErrorTooManyModules(*_pos).into(); } if let Some(path) = self .eval_expr(scope, mods, state, lib, this_ptr, &expr, level)? .try_cast::() { use crate::ModuleResolver; let source = state.source.as_ref().map(|s| s.as_str()); let path_pos = expr.position(); let module = state .embedded_module_resolver .as_ref() .and_then(|r| match r.resolve(self, source, &path, path_pos) { Err(err) if matches!(*err, EvalAltResult::ErrorModuleNotFound(_, _)) => { None } result => Some(result), }) .or_else(|| { self.module_resolver .as_ref() .map(|r| r.resolve(self, source, &path, path_pos)) }) .unwrap_or_else(|| { EvalAltResult::ErrorModuleNotFound(path.to_string(), path_pos).into() })?; if let Some(name) = export.as_ref().map(|x| x.name.clone()) { if !module.is_indexed() { // Index the module (making a clone copy if necessary) if it is not indexed let mut module = crate::fn_native::shared_take_or_clone(module); module.build_index(); mods.push(name, module); } else { mods.push(name, module); } } state.num_modules += 1; Ok(Dynamic::UNIT) } else { Err(self.make_type_mismatch_err::("", expr.position())) } } // Export statement #[cfg(not(feature = "no_module"))] Stmt::Export(list, _) => { for (Ident { name, pos, .. }, Ident { name: rename, .. }) in list.as_ref() { // Mark scope variables as public if let Some((index, _)) = scope.get_index(name) { scope.add_entry_alias( index, if rename.is_empty() { name } else { rename }.clone(), ); } else { return EvalAltResult::ErrorVariableNotFound(name.to_string(), *pos).into(); } } Ok(Dynamic::UNIT) } // Share statement #[cfg(not(feature = "no_closure"))] Stmt::Share(name) => { if let Some((index, _)) = scope.get_index(name) { let val = scope.get_mut_by_index(index); if !val.is_shared() { // Replace the variable with a shared value. *val = std::mem::take(val).into_shared(); } } Ok(Dynamic::UNIT) } }; self.check_return_value(result) .map_err(|err| err.fill_position(stmt.position())) } /// Check a result to ensure that the data size is within allowable limit. fn check_return_value(&self, mut result: RhaiResult) -> RhaiResult { if let Ok(ref mut r) = result { // Concentrate all empty strings into one instance to save memory if let Dynamic(crate::dynamic::Union::Str(s, _, _)) = r { if s.is_empty() { if !s.ptr_eq(&self.constants.empty_string) { *s = self.const_empty_string(); } return result; } } #[cfg(not(feature = "unchecked"))] self.check_data_size(&r)?; } result } #[cfg(feature = "unchecked")] #[inline(always)] fn check_data_size(&self, _value: &Dynamic) -> Result<(), Box> { Ok(()) } #[cfg(not(feature = "unchecked"))] fn check_data_size(&self, value: &Dynamic) -> Result<(), Box> { // Recursively calculate the size of a value (especially `Array` and `Map`) fn calc_size(value: &Dynamic) -> (usize, usize, usize) { match value.0 { #[cfg(not(feature = "no_index"))] Union::Array(ref arr, _, _) => { arr.iter() .fold((0, 0, 0), |(arrays, maps, strings), value| match value.0 { Union::Array(_, _, _) => { let (a, m, s) = calc_size(value); (arrays + a + 1, maps + m, strings + s) } #[cfg(not(feature = "no_object"))] Union::Map(_, _, _) => { let (a, m, s) = calc_size(value); (arrays + a + 1, maps + m, strings + s) } Union::Str(ref s, _, _) => (arrays + 1, maps, strings + s.len()), _ => (arrays + 1, maps, strings), }) } #[cfg(not(feature = "no_object"))] Union::Map(ref map, _, _) => { map.values() .fold((0, 0, 0), |(arrays, maps, strings), value| match value.0 { #[cfg(not(feature = "no_index"))] Union::Array(_, _, _) => { let (a, m, s) = calc_size(value); (arrays + a, maps + m + 1, strings + s) } Union::Map(_, _, _) => { let (a, m, s) = calc_size(value); (arrays + a, maps + m + 1, strings + s) } Union::Str(ref s, _, _) => (arrays, maps + 1, strings + s.len()), _ => (arrays, maps + 1, strings), }) } Union::Str(ref s, _, _) => (0, 0, s.len()), _ => (0, 0, 0), } } // If no data size limits, just return let mut _has_limit = self.limits.max_string_size.is_some(); #[cfg(not(feature = "no_index"))] { _has_limit = _has_limit || self.limits.max_array_size.is_some(); } #[cfg(not(feature = "no_object"))] { _has_limit = _has_limit || self.limits.max_map_size.is_some(); } if !_has_limit { return Ok(()); } let (_arr, _map, s) = calc_size(value); if s > self .limits .max_string_size .map_or(usize::MAX, NonZeroUsize::get) { return EvalAltResult::ErrorDataTooLarge( "Length of string".to_string(), Position::NONE, ) .into(); } #[cfg(not(feature = "no_index"))] if _arr > self .limits .max_array_size .map_or(usize::MAX, NonZeroUsize::get) { return EvalAltResult::ErrorDataTooLarge("Size of array".to_string(), Position::NONE) .into(); } #[cfg(not(feature = "no_object"))] if _map > self .limits .max_map_size .map_or(usize::MAX, NonZeroUsize::get) { return EvalAltResult::ErrorDataTooLarge( "Size of object map".to_string(), Position::NONE, ) .into(); } Ok(()) } /// Check if the number of operations stay within limit. #[cfg(not(feature = "unchecked"))] pub(crate) fn inc_operations( &self, state: &mut EvalState, pos: Position, ) -> Result<(), Box> { state.num_operations += 1; // Guard against too many operations if self.max_operations() > 0 && state.num_operations > self.max_operations() { return EvalAltResult::ErrorTooManyOperations(pos).into(); } // Report progress - only in steps if let Some(ref progress) = self.progress { if let Some(token) = progress(state.num_operations) { // Terminate script if progress returns a termination token return EvalAltResult::ErrorTerminated(token, pos).into(); } } Ok(()) } /// Pretty-print a type name. /// /// If a type is registered via [`register_type_with_name`][Engine::register_type_with_name], /// the type name provided for the registration will be used. #[inline(always)] #[must_use] pub fn map_type_name<'a>(&'a self, name: &'a str) -> &'a str { self.type_names .get(name) .map(|s| s.as_str()) .unwrap_or_else(|| map_std_type_name(name)) } /// Make a `Box<`[`EvalAltResult`][EvalAltResult::ErrorMismatchDataType]`>`. #[inline(always)] #[must_use] pub(crate) fn make_type_mismatch_err(&self, typ: &str, pos: Position) -> Box { EvalAltResult::ErrorMismatchDataType( self.map_type_name(type_name::()).into(), typ.into(), pos, ) .into() } }