rustc_session/config/
externs.rs

1//! This module contains code to help parse and manipulate `--extern` arguments.
2
3use std::path::PathBuf;
4
5use rustc_errors::{Diag, FatalAbort};
6
7use super::UnstableOptions;
8use crate::EarlyDiagCtxt;
9
10#[cfg(test)]
11mod tests;
12
13/// Represents the pieces of an `--extern` argument.
14pub(crate) struct ExternOpt {
15    pub(crate) crate_name: String,
16    pub(crate) path: Option<PathBuf>,
17    pub(crate) options: Option<String>,
18}
19
20/// Breaks out the major components of an `--extern` argument.
21///
22/// The options field will be a string containing comma-separated options that will need further
23/// parsing and processing.
24pub(crate) fn split_extern_opt<'a>(
25    early_dcx: &'a EarlyDiagCtxt,
26    unstable_opts: &UnstableOptions,
27    extern_opt: &str,
28) -> Result<ExternOpt, Diag<'a, FatalAbort>> {
29    let (name, path) = match extern_opt.split_once('=') {
30        None => (extern_opt.to_string(), None),
31        Some((name, path)) => (name.to_string(), Some(PathBuf::from(path))),
32    };
33    let (options, crate_name) = match name.split_once(':') {
34        None => (None, name),
35        Some((opts, crate_name)) => {
36            if unstable_opts.namespaced_crates && crate_name.starts_with(':') {
37                // If the name starts with `:`, we know this was actually something like `foo::bar` and
38                // not a set of options. We can just use the original name as the crate name.
39                (None, name)
40            } else {
41                (Some(opts.to_string()), crate_name.to_string())
42            }
43        }
44    };
45
46    if !valid_crate_name(&crate_name, unstable_opts) {
47        let mut error = early_dcx.early_struct_fatal(format!(
48            "crate name `{crate_name}` passed to `--extern` is not a valid ASCII identifier"
49        ));
50        let adjusted_name = crate_name.replace('-', "_");
51        if is_ascii_ident(&adjusted_name) {
52            #[allow(rustc::diagnostic_outside_of_impl)] // FIXME
53            error
54                .help(format!("consider replacing the dashes with underscores: `{adjusted_name}`"));
55        }
56        return Err(error);
57    }
58
59    Ok(ExternOpt { crate_name, path, options })
60}
61
62fn valid_crate_name(name: &str, unstable_opts: &UnstableOptions) -> bool {
63    match name.split_once("::") {
64        Some((a, b)) if unstable_opts.namespaced_crates => is_ascii_ident(a) && is_ascii_ident(b),
65        Some(_) => false,
66        None => is_ascii_ident(name),
67    }
68}
69
70fn is_ascii_ident(string: &str) -> bool {
71    let mut chars = string.chars();
72    if let Some(start) = chars.next()
73        && (start.is_ascii_alphabetic() || start == '_')
74    {
75        chars.all(|char| char.is_ascii_alphanumeric() || char == '_')
76    } else {
77        false
78    }
79}
rustc_session/config/externs.rs

rustc_session/config/
externs.rs
