translation.rs

use std::borrow::Cow;
use std::env;
use std::error::Report;
use std::sync::Arc;

pub use rustc_error_messages::{FluentArgs, LazyFallbackBundle};
use rustc_error_messages::{langid, register_functions};
use tracing::{debug, trace};

use crate::error::{TranslateError, TranslateErrorKind};
use crate::fluent_bundle::FluentResource;
use crate::{DiagArg, DiagMessage, FluentBundle, Style, fluent_bundle};

/// Convert diagnostic arguments (a rustc internal type that exists to implement
/// `Encodable`/`Decodable`) into `FluentArgs` which is necessary to perform translation.
///
/// Typically performed once for each diagnostic at the start of `emit_diagnostic` and then
/// passed around as a reference thereafter.
pub fn to_fluent_args<'iter>(iter: impl Iterator<Item = DiagArg<'iter>>) -> FluentArgs<'static> {
    let mut args = if let Some(size) = iter.size_hint().1 {
        FluentArgs::with_capacity(size)
    } else {
        FluentArgs::new()
    };

    for (k, v) in iter {
        args.set(k.clone(), v.clone());
    }

    args
}

#[derive(Clone)]
pub struct Translator {
    /// Localized diagnostics for the locale requested by the user. If no language was requested by
    /// the user then this will be `None` and `fallback_fluent_bundle` should be used.
    pub fluent_bundle: Option<Arc<FluentBundle>>,
    /// Return `FluentBundle` with localized diagnostics for the default locale of the compiler.
    /// Used when the user has not requested a specific language or when a localized diagnostic is
    /// unavailable for the requested locale.
    pub fallback_fluent_bundle: LazyFallbackBundle,
}

impl Translator {
    pub fn with_fallback_bundle(
        resources: Vec<&'static str>,
        with_directionality_markers: bool,
    ) -> Translator {
        Translator {
            fluent_bundle: None,
            fallback_fluent_bundle: crate::fallback_fluent_bundle(
                resources,
                with_directionality_markers,
            ),
        }
    }

    /// Convert `DiagMessage`s to a string, performing translation if necessary.
    pub fn translate_messages(
        &self,
        messages: &[(DiagMessage, Style)],
        args: &FluentArgs<'_>,
    ) -> Cow<'_, str> {
        Cow::Owned(
            messages
                .iter()
                .map(|(m, _)| self.translate_message(m, args).map_err(Report::new).unwrap())
                .collect::<String>(),
        )
    }

    /// Convert a `DiagMessage` to a string, performing translation if necessary.
    pub fn translate_message<'a>(
        &'a self,
        message: &'a DiagMessage,
        args: &'a FluentArgs<'_>,
    ) -> Result<Cow<'a, str>, TranslateError<'a>> {
        Ok(Cow::Borrowed("Temporary message"))
    }
}

/// This macro creates a translatable `DiagMessage` from a literal string.
/// It should be used in places where a translatable message is needed, but struct diagnostics are undesired.
///
/// This is a macro because in the future we may want to globally register these messages.
#[macro_export]
macro_rules! inline_fluent {
    ($inline: literal) => {
        rustc_errors::DiagMessage::Inline(std::borrow::Cow::Borrowed($inline))
    };
}