36 lines
1.4 KiB
Rust
36 lines
1.4 KiB
Rust
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use rustc_ast::attr::AttributeExt;
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use crate::types::TransparencyError;
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use rustc_span::{hygiene::Transparency, sym};
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pub fn find_transparency(
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attrs: &[impl AttributeExt],
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macro_rules: bool,
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) -> (Transparency, Option<TransparencyError>) {
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let mut transparency = None;
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let mut error = None;
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for attr in attrs {
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if attr.has_name(sym::rustc_macro_transparency) {
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if let Some((_, old_span)) = transparency {
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error = Some(TransparencyError::MultipleTransparencyAttrs(old_span, attr.span()));
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break;
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} else if let Some(value) = attr.value_str() {
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transparency = Some((
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match value {
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sym::transparent => Transparency::Transparent,
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sym::semitransparent => Transparency::SemiTransparent,
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sym::opaque => Transparency::Opaque,
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_ => {
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error =
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Some(TransparencyError::UnknownTransparency(value, attr.span()));
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continue;
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}
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},
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attr.span(),
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));
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}
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}
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}
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let fallback = if macro_rules { Transparency::SemiTransparent } else { Transparency::Opaque };
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(transparency.map_or(fallback, |t| t.0), error)
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}
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