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use crate::bundle::FluentBundle;
use crate::memoizer::MemoizerKind;
use crate::resolver::{ResolveValue, ResolverError, WriteValue};
use crate::types::FluentValue;
use crate::{FluentArgs, FluentError, FluentResource};
use fluent_syntax::ast;
use std::borrow::Borrow;
use std::fmt;
/// State for a single `ResolveValue::to_value` call.
pub struct Scope<'scope, 'errors, R, M> {
/// The current `FluentBundle` instance.
pub bundle: &'scope FluentBundle<R, M>,
/// The current arguments passed by the developer.
pub(super) args: Option<&'scope FluentArgs<'scope>>,
/// Local args
pub(super) local_args: Option<FluentArgs<'scope>>,
/// The running count of resolved placeables. Used to detect the Billion
/// Laughs and Quadratic Blowup attacks.
pub(super) placeables: u8,
/// Tracks hashes to prevent infinite recursion.
travelled: smallvec::SmallVec<[&'scope ast::Pattern<&'scope str>; 2]>,
/// Track errors accumulated during resolving.
pub errors: Option<&'errors mut Vec<FluentError>>,
/// Makes the resolver bail.
pub dirty: bool,
}
impl<'scope, 'errors, R, M> Scope<'scope, 'errors, R, M> {
pub fn new(
bundle: &'scope FluentBundle<R, M>,
args: Option<&'scope FluentArgs>,
errors: Option<&'errors mut Vec<FluentError>>,
) -> Self {
Scope {
bundle,
args,
local_args: None,
placeables: 0,
travelled: Default::default(),
errors,
dirty: false,
}
}
pub fn add_error(&mut self, error: ResolverError) {
if let Some(errors) = self.errors.as_mut() {
errors.push(error.into());
}
}
// This method allows us to lazily add Pattern on the stack,
// only if the Pattern::resolve has been called on an empty stack.
//
// This is the case when pattern is called from Bundle and it
// allows us to fast-path simple resolutions, and only use the stack
// for placeables.
pub fn maybe_track<W>(
&mut self,
w: &mut W,
pattern: &'scope ast::Pattern<&str>,
exp: &'scope ast::Expression<&str>,
) -> fmt::Result
where
R: Borrow<FluentResource>,
W: fmt::Write,
M: MemoizerKind,
{
if self.travelled.is_empty() {
self.travelled.push(pattern);
}
exp.write(w, self)?;
if self.dirty {
w.write_char('{')?;
exp.write_error(w)?;
w.write_char('}')
} else {
Ok(())
}
}
pub fn track<W>(
&mut self,
w: &mut W,
pattern: &'scope ast::Pattern<&str>,
exp: &ast::InlineExpression<&str>,
) -> fmt::Result
where
R: Borrow<FluentResource>,
W: fmt::Write,
M: MemoizerKind,
{
if self.travelled.contains(&pattern) {
self.add_error(ResolverError::Cyclic);
w.write_char('{')?;
exp.write_error(w)?;
w.write_char('}')
} else {
self.travelled.push(pattern);
let result = pattern.write(w, self);
self.travelled.pop();
result
}
}
pub fn write_ref_error<W>(
&mut self,
w: &mut W,
exp: &ast::InlineExpression<&str>,
) -> fmt::Result
where
W: fmt::Write,
{
self.add_error(exp.into());
w.write_char('{')?;
exp.write_error(w)?;
w.write_char('}')
}
pub fn get_arguments(
&mut self,
arguments: Option<&'scope ast::CallArguments<&'scope str>>,
) -> (Vec<FluentValue<'scope>>, FluentArgs<'scope>)
where
R: Borrow<FluentResource>,
M: MemoizerKind,
{
if let Some(ast::CallArguments { positional, named }) = arguments {
let positional = positional.iter().map(|expr| expr.resolve(self)).collect();
let named = named
.iter()
.map(|arg| (arg.name.name, arg.value.resolve(self)))
.collect();
(positional, named)
} else {
(Vec::new(), FluentArgs::new())
}
}
}