garando_syntax2 0.1.0

use std::cell::RefCell;
use std::collections::BTreeMap;
use std::env;

use crate::ast;
use crate::ast::{Ident, Name};
use crate::ext::base::{ExtCtxt, MacEager, MacResult};
use crate::ext::build::AstBuilder;
use crate::parse::token;
use crate::ptr::P;
use crate::symbol::Symbol;
use crate::syntax_pos::Span;
use crate::tokenstream::TokenTree;
use crate::util::small_vector::SmallVector;

use crate::diagnostics::metadata::output_metadata;

pub use crate::errors::*;

// Maximum width of any line in an extended error description (inclusive).
const MAX_DESCRIPTION_WIDTH: usize = 80;

thread_local! {
    static REGISTERED_DIAGNOSTICS: RefCell<ErrorMap> = {
        RefCell::new(BTreeMap::new())
    }
}

/// Error information type.
pub struct ErrorInfo {
    pub description: Option<Name>,
    pub use_site: Option<Span>,
}

/// Mapping from error codes to metadata.
pub type ErrorMap = BTreeMap<Name, ErrorInfo>;

fn with_registered_diagnostics<T, F>(f: F) -> T
where
    F: FnOnce(&mut ErrorMap) -> T,
{
    REGISTERED_DIAGNOSTICS.with(move |slot| f(&mut *slot.borrow_mut()))
}

pub fn expand_diagnostic_used<'cx>(
    ecx: &'cx mut ExtCtxt,
    span: Span,
    token_tree: &[TokenTree],
) -> Box<dyn MacResult + 'cx> {
    let code = match (token_tree.len(), token_tree.get(0)) {
        (1, Some(&TokenTree::Token(_, token::Ident(code)))) => code,
        _ => unreachable!(),
    };

    with_registered_diagnostics(|diagnostics| {
        match diagnostics.get_mut(&code.name) {
            // Previously used errors.
            Some(&mut ErrorInfo {
                description: _,
                use_site: Some(previous_span),
            }) => {
                ecx.struct_span_warn(span, &format!("diagnostic code {} already used", code))
                    .span_note(previous_span, "previous invocation")
                    .emit();
            }
            // Newly used errors.
            Some(ref mut info) => {
                info.use_site = Some(span);
            }
            // Unregistered errors.
            None => {
                ecx.span_err(
                    span,
                    &format!("used diagnostic code {} not registered", code),
                );
            }
        }
    });
    MacEager::expr(ecx.expr_tuple(span, Vec::new()))
}

pub fn expand_register_diagnostic<'cx>(
    ecx: &'cx mut ExtCtxt,
    span: Span,
    token_tree: &[TokenTree],
) -> Box<dyn MacResult + 'cx> {
    let (code, description) = match (
        token_tree.len(),
        token_tree.get(0),
        token_tree.get(1),
        token_tree.get(2),
    ) {
        (1, Some(&TokenTree::Token(_, token::Ident(ref code))), None, None) => (code, None),
        (
            3,
            Some(&TokenTree::Token(_, token::Ident(ref code))),
            Some(&TokenTree::Token(_, token::Comma)),
            Some(&TokenTree::Token(_, token::Literal(token::StrRaw(description, _), None))),
        ) => (code, Some(description)),
        _ => unreachable!(),
    };

    // Check that the description starts and ends with a newline and doesn't
    // overflow the maximum line width.
    description.map(|raw_msg| {
        let msg = raw_msg.as_str();
        if !msg.starts_with("\n") || !msg.ends_with("\n") {
            ecx.span_err(
                span,
                &format!(
                    "description for error code {} doesn't start and end with a newline",
                    code
                ),
            );
        }

        // URLs can be unavoidably longer than the line limit, so we allow them.
        // Allowed format is: `[name]: https://www.rust-lang.org/`
        let is_url = |l: &str| l.starts_with("[") && l.contains("]:") && l.contains("http");

        if msg
            .lines()
            .any(|line| line.len() > MAX_DESCRIPTION_WIDTH && !is_url(line))
        {
            ecx.span_err(
                span,
                &format!(
                    "description for error code {} contains a line longer than {} characters.\n\
                 if you're inserting a long URL use the footnote style to bypass this check.",
                    code, MAX_DESCRIPTION_WIDTH
                ),
            );
        }
    });
    // Add the error to the map.
    with_registered_diagnostics(|diagnostics| {
        let info = ErrorInfo {
            description: description,
            use_site: None,
        };
        if diagnostics.insert(code.name, info).is_some() {
            ecx.span_err(
                span,
                &format!("diagnostic code {} already registered", code),
            );
        }
    });
    let sym = Ident::with_empty_ctxt(Symbol::gensym(&format!("__register_diagnostic_{}", code)));
    MacEager::items(SmallVector::many(vec![ecx.item_mod(
        span,
        span,
        sym,
        Vec::new(),
        Vec::new(),
    )]))
}

pub fn expand_build_diagnostic_array<'cx>(
    ecx: &'cx mut ExtCtxt,
    span: Span,
    token_tree: &[TokenTree],
) -> Box<dyn MacResult + 'cx> {
    assert_eq!(token_tree.len(), 3);
    let (crate_name, name) = match (&token_tree[0], &token_tree[2]) {
        (
            // Crate name.
            &TokenTree::Token(_, token::Ident(ref crate_name)),
            // DIAGNOSTICS ident.
            &TokenTree::Token(_, token::Ident(ref name)),
        ) => (*&crate_name, name),
        _ => unreachable!(),
    };

    // Output error metadata to `tmp/extended-errors/<target arch>/<crate name>.json`
    if let Ok(target_triple) = env::var("CFG_COMPILER_HOST_TRIPLE") {
        with_registered_diagnostics(|diagnostics| {
            if let Err(e) =
                output_metadata(ecx, &target_triple, &crate_name.name.as_str(), diagnostics)
            {
                ecx.span_bug(
                    span,
                    &format!(
                        "error writing metadata for triple `{}` and crate `{}`, error: {}, \
                     cause: {:?}",
                        target_triple,
                        crate_name,
                        e.to_string(),
                        e.source()
                    ),
                );
            }
        });
    } else {
        ecx.span_err(
            span,
            &format!(
            "failed to write metadata for crate `{}` because $CFG_COMPILER_HOST_TRIPLE is not set",
            crate_name),
        );
    }

    // Construct the output expression.
    let (count, expr) = with_registered_diagnostics(|diagnostics| {
        let descriptions: Vec<P<ast::Expr>> = diagnostics
            .iter()
            .filter_map(|(&code, info)| {
                info.description.map(|description| {
                    ecx.expr_tuple(
                        span,
                        vec![ecx.expr_str(span, code), ecx.expr_str(span, description)],
                    )
                })
            })
            .collect();
        (descriptions.len(), ecx.expr_vec(span, descriptions))
    });

    let static_ = ecx.lifetime(span, Ident::from_str("'static"));
    let ty_str = ecx.ty_rptr(
        span,
        ecx.ty_ident(span, ecx.ident_of("str")),
        Some(static_),
        ast::Mutability::Immutable,
    );

    let ty = ecx.ty(
        span,
        ast::TyKind::Array(
            ecx.ty(span, ast::TyKind::Tup(vec![ty_str.clone(), ty_str])),
            ecx.expr_usize(span, count),
        ),
    );

    MacEager::items(SmallVector::many(vec![P(ast::Item {
        ident: *name,
        attrs: Vec::new(),
        id: ast::DUMMY_NODE_ID,
        node: ast::ItemKind::Const(ty, expr),
        vis: ast::Visibility::Public,
        span: span,
    })]))
}