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Run var def filter during parsing.

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This commit is contained in:
Stephen Chung 2022-02-13 18:46:25 +08:00
parent 664e3d31e5
commit 5bb6ce835f
9 changed files with 115 additions and 49 deletions
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2
CHANGELOG.md
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@ -38,7 +38,7 @@ New features
* A new package, `DebuggingPackage`, is added which contains the `back_trace` function to get the current call stack anywhere in a script.
* `Engine::set_fail_on_invalid_map_property` is added to control whether to raise an error (new `EvalAltResult::ErrorPropertyNotFound`) when invalid properties are accessed on object maps.
* `Engine::set_allow_shadowing` is added to allow/disallow variables _shadowing_, with new errors `EvalAltResult::ErrorVariableExists` and `ParseErrorType::VariableExists`.
* `Engine::on_def_var` allows registering a closure which can decide whether a variable definition is allow to continue, or should fail with an error.
* `Engine::on_def_var` allows registering a closure which can decide whether a variable definition is allow to continue, during compilation or runtime, or should fail with an error (`ParseErrorType::ForbiddenVariable` or `EvalAltResult::ErrorForbiddenVariable`).
* A new syntax for defining custom packages is introduced that removes the need to specify the Rhai crate name (internally uses the `$crate` meta variable).
Enhancements

7
src/api/events.rs
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@ -73,8 +73,9 @@ impl Engine {
///
/// where:
/// * `name`: name of the variable to be defined.
/// * `is_runtime`: `true` if the variable definition event happens during runtime, `false` if during compilation.
/// * `is_const`: `true` if the statement is `const`, otherwise it is `let`.
/// * `block_level`: the current nesting level of statement blocks, with zero being the global level
/// * `block_level`: the current nesting level of statement blocks, with zero being the global level.
/// * `will_shadow`: will the variable _shadow_ an existing variable?
/// * `context`: the current [evaluation context][`EvalContext`].
///
@ -96,7 +97,7 @@ impl Engine {
/// let mut engine = Engine::new();
///
/// // Register a variable definition filter.
/// engine.on_def_var(|name, is_const, _, _, _| {
/// engine.on_def_var(|name, _, is_const, _, _, _| {
/// // Disallow defining MYSTIC_NUMBER as a constant
/// if name == "MYSTIC_NUMBER" && is_const {
/// Ok(false)
@ -117,7 +118,7 @@ impl Engine {
#[inline(always)]
pub fn on_def_var(
&mut self,
callback: impl Fn(&str, bool, usize, bool, &EvalContext) -> RhaiResultOf<bool>
callback: impl Fn(&str, bool, bool, usize, bool, &EvalContext) -> RhaiResultOf<bool>
+ SendSync
+ 'static,
) -> &mut Self {

12
src/eval/stmt.rs
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@ -831,13 +831,13 @@ impl Engine {
level: level,
};
match filter(var_name, is_const, scope_level, shadowing, &context) {
match filter(var_name, true, is_const, scope_level, shadowing, &context) {
Ok(true) => None,
Ok(false) => Some(Err(ERR::ErrorRuntime(
format!("Variable cannot be defined: {}", var_name).into(),
*pos,
)
.into())),
Ok(false) => {
Some(Err(
ERR::ErrorForbiddenVariable(var_name.to_string(), *pos).into()
))
}
err @ Err(_) => Some(err),
}
} else {

5
src/func/native.rs
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@ -447,8 +447,9 @@ pub type OnVarCallback =
/// Callback function for variable definition.
#[cfg(not(feature = "sync"))]
pub type OnDefVarCallback = dyn Fn(&str, bool, usize, bool, &EvalContext) -> RhaiResultOf<bool>;
pub type OnDefVarCallback =
dyn Fn(&str, bool, bool, usize, bool, &EvalContext) -> RhaiResultOf<bool>;
/// Callback function for variable definition.
#[cfg(feature = "sync")]
pub type OnDefVarCallback =
dyn Fn(&str, bool, usize, bool, &EvalContext) -> RhaiResultOf<bool> + Send + Sync;
dyn Fn(&str, bool, bool, usize, bool, &EvalContext) -> RhaiResultOf<bool> + Send + Sync;

102
src/parser.rs
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@ -7,6 +7,7 @@ use crate::ast::{
OpAssignment, ScriptFnDef, Stmt, SwitchCases, TryCatchBlock, AST_OPTION_FLAGS::*,
};
use crate::engine::{Precedence, KEYWORD_THIS, OP_CONTAINS};
use crate::eval::{EvalState, GlobalRuntimeState};
use crate::func::hashing::get_hasher;
use crate::tokenizer::{
is_keyword_function, is_valid_function_name, is_valid_identifier, Span, Token, TokenStream,
@ -15,8 +16,9 @@ use crate::tokenizer::{
use crate::types::dynamic::AccessMode;
use crate::types::StringsInterner;
use crate::{
calc_fn_hash, Dynamic, Engine, ExclusiveRange, Identifier, ImmutableString, InclusiveRange,
LexError, OptimizationLevel, ParseError, Position, Scope, Shared, StaticVec, AST, INT, PERR,
calc_fn_hash, Dynamic, Engine, EvalAltResult, EvalContext, ExclusiveRange, Identifier,
ImmutableString, InclusiveRange, LexError, OptimizationLevel, ParseError, Position, Scope,
Shared, StaticVec, AST, INT, PERR,
};
#[cfg(feature = "no_std")]
use std::prelude::v1::*;
@ -47,7 +49,7 @@ pub struct ParseState<'e> {
/// Interned strings.
pub interned_strings: StringsInterner,
/// Encapsulates a local stack with variable names to simulate an actual runtime scope.
pub stack: StaticVec<(Identifier, AccessMode)>,
pub stack: Scope<'e>,
/// Size of the local variables stack upon entry of the current block scope.
pub entry_stack_len: usize,
/// Tracks a list of external variables (variables that are not explicitly declared in the scope).
@ -89,7 +91,7 @@ impl<'e> ParseState<'e> {
#[cfg(not(feature = "no_closure"))]
allow_capture: true,
interned_strings: StringsInterner::new(),
stack: StaticVec::new_const(),
stack: Scope::new(),
entry_stack_len: 0,
#[cfg(not(feature = "no_module"))]
imports: StaticVec::new_const(),
@ -112,10 +114,9 @@ impl<'e> ParseState<'e> {
let index = self
.stack
.iter()
.rev()
.iter_rev_raw()
.enumerate()
.find(|(.., (n, ..))| {
.find(|&(.., (n, ..))| {
if n == SCOPE_SEARCH_BARRIER_MARKER {
// Do not go beyond the barrier
barrier = true;
@ -1337,13 +1338,11 @@ fn parse_primary(
}
if segments.is_empty() {
segments.push(Expr::StringConstant(
state.get_interned_string("", ""),
settings.pos,
));
Expr::StringConstant(state.get_interned_string("", ""), settings.pos)
} else {
segments.shrink_to_fit();
Expr::InterpolatedString(segments.into(), settings.pos)
}
segments.shrink_to_fit();
Expr::InterpolatedString(segments.into(), settings.pos)
}
// Array literal
@ -1802,7 +1801,11 @@ fn make_assignment_stmt(
|| index.expect("either long or short index is `None`").get(),
|n| n.get() as usize,
);
match state.stack[state.stack.len() - index].1 {
match state
.stack
.get_mut_by_index(state.stack.len() - index)
.access_mode()
{
AccessMode::ReadWrite => Ok(Stmt::Assignment(
(op_info, (lhs, rhs).into()).into(),
op_pos,
@ -2195,7 +2198,7 @@ fn parse_custom_syntax(
// Add a barrier variable to the stack so earlier variables will not be matched.
// Variable searches stop at the first barrier.
let marker = state.get_identifier("", SCOPE_SEARCH_BARRIER_MARKER);
state.stack.push((marker, AccessMode::ReadWrite));
state.stack.push(marker, ());
}
let parse_func = syntax.parse.as_ref();
@ -2562,21 +2565,24 @@ fn parse_for(
let counter_var = counter_name.map(|name| {
let name = state.get_identifier("", name);
let pos = counter_pos.expect("`Some`");
state.stack.push((name.clone(), AccessMode::ReadWrite));
Ident { name, pos }
state.stack.push(name.clone(), ());
Ident {
name: name.clone(),
pos,
}
});
let loop_var = state.get_identifier("", name);
state.stack.push((loop_var.clone(), AccessMode::ReadWrite));
state.stack.push(loop_var.clone(), ());
let loop_var = Ident {
name: loop_var,
name: loop_var.clone(),
pos: name_pos,
};
settings.is_breakable = true;
let body = parse_block(input, state, lib, settings.level_up())?;
state.stack.truncate(prev_stack_len);
state.stack.rewind(prev_stack_len);
Ok(Stmt::For(
expr,
@ -2610,6 +2616,30 @@ fn parse_let(
return Err(PERR::VariableExists(name.to_string()).into_err(pos));
}
if let Some(ref filter) = state.engine.def_var_filter {
let shadowing = state.stack.iter().any(|(v, ..)| v == name.as_ref());
let level = settings.level;
let is_const = var_type == AccessMode::ReadOnly;
let context = EvalContext {
engine: state.engine,
scope: &mut state.stack,
global: &mut GlobalRuntimeState::new(state.engine),
state: &mut EvalState::new(),
lib: &[],
this_ptr: &mut None,
level,
};
match filter(&name, false, is_const, level, shadowing, &context) {
Ok(true) => (),
Ok(false) => return Err(PERR::ForbiddenVariable(name.to_string()).into_err(pos)),
Err(err) => match *err {
EvalAltResult::ErrorParsing(perr, pos) => return Err(perr.into_err(pos)),
_ => return Err(PERR::ForbiddenVariable(name.to_string()).into_err(pos)),
},
}
}
let name = state.get_identifier("", name);
let var_def = Ident {
name: name.clone(),
@ -2624,8 +2654,6 @@ fn parse_let(
Expr::Unit(Position::NONE)
};
state.stack.push((name, var_type));
let export = if is_export {
AST_OPTION_EXPORTED
} else {
@ -2634,14 +2662,20 @@ fn parse_let(
match var_type {
// let name = expr
AccessMode::ReadWrite => Ok(Stmt::Var(expr, var_def.into(), export, settings.pos)),
AccessMode::ReadWrite => {
state.stack.push(name, ());
Ok(Stmt::Var(expr, var_def.into(), export, settings.pos))
}
// const name = { expr:constant }
AccessMode::ReadOnly => Ok(Stmt::Var(
expr,
var_def.into(),
AST_OPTION_CONSTANT + export,
settings.pos,
)),
AccessMode::ReadOnly => {
state.stack.push_constant(name, ());
Ok(Stmt::Var(
expr,
var_def.into(),
AST_OPTION_CONSTANT + export,
settings.pos,
))
}
}
}
@ -2820,7 +2854,7 @@ fn parse_block(
}
};
state.stack.truncate(state.entry_stack_len);
state.stack.rewind(state.entry_stack_len);
state.entry_stack_len = prev_entry_stack_len;
#[cfg(not(feature = "no_module"))]
@ -3106,7 +3140,7 @@ fn parse_try_catch(
}
let name = state.get_identifier("", name);
state.stack.push((name.clone(), AccessMode::ReadWrite));
state.stack.push(name.clone(), ());
Some(Ident { name, pos })
} else {
None
@ -3117,7 +3151,7 @@ fn parse_try_catch(
if catch_var.is_some() {
// Remove the error variable from the stack
state.stack.pop().unwrap();
state.stack.rewind(state.stack.len() - 1);
}
Ok(Stmt::TryCatch(
@ -3176,7 +3210,7 @@ fn parse_fn(
);
}
let s = state.get_identifier("", s);
state.stack.push((s.clone(), AccessMode::ReadWrite));
state.stack.push(s.clone(), ());
params.push((s, pos))
}
(Token::LexError(err), pos) => return Err(err.into_err(pos)),
@ -3319,7 +3353,7 @@ fn parse_anon_fn(
);
}
let s = state.get_identifier("", s);
state.stack.push((s.clone(), AccessMode::ReadWrite));
state.stack.push(s.clone(), ());
params_list.push(s)
}
(Token::LexError(err), pos) => return Err(err.into_err(pos)),

7
src/types/error.rs
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@ -36,6 +36,8 @@ pub enum EvalAltResult {
/// Shadowing of an existing variable disallowed. Wrapped value is the variable name.
ErrorVariableExists(String, Position),
/// Forbidden variable name. Wrapped value is the variable name.
ErrorForbiddenVariable(String, Position),
/// Access of an unknown variable. Wrapped value is the variable name.
ErrorVariableNotFound(String, Position),
/// Access of an unknown object map property. Wrapped value is the property name.
@ -148,6 +150,7 @@ impl fmt::Display for EvalAltResult {
Self::ErrorInModule(s, err, ..) => write!(f, "Error in module {}: {}", s, err)?,
Self::ErrorVariableExists(s, ..) => write!(f, "Variable is already defined: {}", s)?,
Self::ErrorForbiddenVariable(s, ..) => write!(f, "Forbidden variable name: {}", s)?,
Self::ErrorVariableNotFound(s, ..) => write!(f, "Variable not found: {}", s)?,
Self::ErrorPropertyNotFound(s, ..) => write!(f, "Property not found: {}", s)?,
Self::ErrorFunctionNotFound(s, ..) => write!(f, "Function not found: {}", s)?,
@ -285,6 +288,7 @@ impl EvalAltResult {
| Self::ErrorIndexingType(..)
| Self::ErrorFor(..)
| Self::ErrorVariableExists(..)
| Self::ErrorForbiddenVariable(..)
| Self::ErrorVariableNotFound(..)
| Self::ErrorPropertyNotFound(..)
| Self::ErrorModuleNotFound(..)
@ -377,6 +381,7 @@ impl EvalAltResult {
map.insert("type".into(), t.into());
}
Self::ErrorVariableExists(v, ..)
| Self::ErrorForbiddenVariable(v, ..)
| Self::ErrorVariableNotFound(v, ..)
| Self::ErrorPropertyNotFound(v, ..)
| Self::ErrorDataRace(v, ..)
@ -440,6 +445,7 @@ impl EvalAltResult {
| Self::ErrorIndexingType(.., pos)
| Self::ErrorFor(pos)
| Self::ErrorVariableExists(.., pos)
| Self::ErrorForbiddenVariable(.., pos)
| Self::ErrorVariableNotFound(.., pos)
| Self::ErrorPropertyNotFound(.., pos)
| Self::ErrorModuleNotFound(.., pos)
@ -490,6 +496,7 @@ impl EvalAltResult {
| Self::ErrorIndexingType(.., pos)
| Self::ErrorFor(pos)
| Self::ErrorVariableExists(.., pos)
| Self::ErrorForbiddenVariable(.., pos)
| Self::ErrorVariableNotFound(.., pos)
| Self::ErrorPropertyNotFound(.., pos)
| Self::ErrorModuleNotFound(.., pos)

3
src/types/parse_error.rs
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@ -109,6 +109,8 @@ pub enum ParseErrorType {
PropertyExpected,
/// Missing a variable name after the `let`, `const`, `for` or `catch` keywords.
VariableExpected,
/// Forbidden variable name. Wrapped value is the variable name.
ForbiddenVariable(String),
/// An identifier is a reserved symbol.
Reserved(String),
/// An expression is of the wrong type.
@ -240,6 +242,7 @@ impl fmt::Display for ParseErrorType {
Self::WrongSwitchCaseCondition => f.write_str("This switch case cannot have a condition"),
Self::PropertyExpected => f.write_str("Expecting name of a property"),
Self::VariableExpected => f.write_str("Expecting name of a variable"),
Self::ForbiddenVariable(s) => write!(f, "Forbidden variable name: {}", s),
Self::WrongFnDefinition => f.write_str("Function definitions must be at global level and cannot be inside a block or another function"),
Self::FnMissingName => f.write_str("Expecting function name in function declaration"),
Self::WrongDocComment => f.write_str("Doc-comment must be followed immediately by a function definition"),

10
src/types/scope.rs
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@ -595,6 +595,16 @@ impl Scope<'_> {
.zip(self.values.iter())
.map(|((name, ..), value)| (name.as_ref(), value.is_read_only(), value))
}
/// Get a reverse iterator to entries in the [`Scope`].
/// Shared values are not expanded.
#[inline]
pub(crate) fn iter_rev_raw(&self) -> impl Iterator<Item = (&str, bool, &Dynamic)> {
self.names
.iter()
.rev()
.zip(self.values.iter().rev())
.map(|((name, ..), value)| (name.as_ref(), value.is_read_only(), value))
}
/// Remove a range of entries within the [`Scope`].
///
/// # Panics

16
tests/var_scope.rs
View File

@ -1,4 +1,4 @@
use rhai::{Engine, EvalAltResult, Position, Scope, INT};
use rhai::{Engine, EvalAltResult, ParseErrorType, Position, Scope, INT};
#[test]
fn test_var_scope() -> Result<(), Box<EvalAltResult>> {
@ -125,7 +125,10 @@ fn test_var_resolver() -> Result<(), Box<EvalAltResult>> {
fn test_var_def_filter() -> Result<(), Box<EvalAltResult>> {
let mut engine = Engine::new();
engine.on_def_var(|name, _, scope_level, _, _| match (name, scope_level) {
let ast = engine.compile("let x = 42;")?;
engine.run_ast(&ast)?;
engine.on_def_var(|name, _, _, scope_level, _, _| match (name, scope_level) {
("x", 0 | 1) => Ok(false),
_ => Ok(true),
});
@ -135,7 +138,14 @@ fn test_var_def_filter() -> Result<(), Box<EvalAltResult>> {
124
);
assert!(engine.run("let x = 42;").is_err());
assert!(matches!(
*engine.compile("let x = 42;").expect_err("should error").0,
ParseErrorType::ForbiddenVariable(s) if s == "x"
));
assert!(matches!(
*engine.run_ast(&ast).expect_err("should err"),
EvalAltResult::ErrorForbiddenVariable(s, _) if s == "x"
));
assert!(engine.run("const x = 42;").is_err());
assert!(engine.run("let y = 42; { let x = y + 1; }").is_err());
assert!(engine.run("let y = 42; { let x = y + 1; }").is_err());