55 lines
2.0 KiB
Rust
55 lines
2.0 KiB
Rust
use rustc::lint::Context;
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use syntax::ast::{DefId, Name, Path};
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use syntax::codemap::{ExpnInfo, Span};
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use syntax::ptr::P;
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use rustc::middle::ty;
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use std::borrow::{Cow, IntoCow};
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use std::convert::From;
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/// returns true if the macro that expanded the crate was outside of
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/// the current crate or was a compiler plugin
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pub fn in_macro(cx: &Context, opt_info: Option<&ExpnInfo>) -> bool {
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// no ExpnInfo = no macro
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opt_info.map_or(false, |info| {
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// no span for the callee = external macro
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info.callee.span.map_or(true, |span| {
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// no snippet = external macro or compiler-builtin expansion
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cx.sess().codemap().span_to_snippet(span).ok().map_or(true, |code|
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// macro doesn't start with "macro_rules"
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// = compiler plugin
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!code.starts_with("macro_rules")
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)
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})
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})
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}
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/// invokes in_macro with the expansion info of the given span
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pub fn in_external_macro(cx: &Context, span: Span) -> bool {
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cx.sess().codemap().with_expn_info(span.expn_id,
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|info| in_macro(cx, info))
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}
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/// check if a DefId's path matches the given absolute type path
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/// usage e.g. with
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/// `match_def_path(cx, id, &["core", "option", "Option"])`
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pub fn match_def_path(cx: &Context, def_id: DefId, path: &[&str]) -> bool {
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cx.tcx.with_path(def_id, |iter| iter.map(|elem| elem.name())
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.zip(path.iter()).all(|(nm, p)| &nm.as_str() == p))
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}
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/// match a Path against a slice of segment string literals, e.g.
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/// `match_path(path, &["std", "rt", "begin_unwind"])`
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pub fn match_path(path: &Path, segments: &[&str]) -> bool {
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path.segments.iter().rev().zip(segments.iter().rev()).all(
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|(a,b)| a.identifier.as_str() == *b)
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}
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/// convert a span to a code snippet if available, otherwise use default, e.g.
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/// `snippet(cx, expr.span, "..")`
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pub fn snippet<'a>(cx: &Context, span: Span, default: &'a str) -> Cow<'a, str> {
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cx.sess().codemap().span_to_snippet(span).map(From::from).unwrap_or(Cow::Borrowed(default))
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}
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/// dereference a P<T> and return a ref on the result
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pub fn de_p<T>(p: &P<T>) -> &T { &*p }
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