179 lines
6.2 KiB
Rust
179 lines
6.2 KiB
Rust
use rustc::lint::{Context, Lint, Level};
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use syntax::ast::{DefId, Expr, Name, NodeId, Path};
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use syntax::codemap::{ExpnInfo, Span};
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use syntax::ptr::P;
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use rustc::ast_map::Node::NodeExpr;
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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 == 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.name == 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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/// convert a span (from a block) to a code snippet if available, otherwise use default, e.g.
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/// `snippet(cx, expr.span, "..")`
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/// This trims the code of indentation, except for the first line
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/// Use it for blocks or block-like things which need to be printed as such
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pub fn snippet_block<'a>(cx: &Context, span: Span, default: &'a str) -> Cow<'a, str> {
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let snip = snippet(cx, span, default);
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trim_multiline(snip, true)
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}
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/// Trim indentation from a multiline string
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/// with possibility of ignoring the first line
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pub fn trim_multiline(s: Cow<str>, ignore_first: bool) -> Cow<str> {
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let s = trim_multiline_inner(s, ignore_first, ' ');
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let s = trim_multiline_inner(s, ignore_first, '\t');
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trim_multiline_inner(s, ignore_first, ' ')
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}
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fn trim_multiline_inner(s: Cow<str>, ignore_first: bool, ch: char) -> Cow<str> {
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let x = s.lines().skip(ignore_first as usize)
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.filter_map(|l| { if l.len() > 0 { // ignore empty lines
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Some(l.char_indices()
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.find(|&(_,x)| x != ch)
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.unwrap_or((l.len(), ch)).0)
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} else {None}})
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.min().unwrap_or(0);
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if x > 0 {
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Cow::Owned(s.lines().enumerate().map(|(i,l)| if (ignore_first && i == 0) ||
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l.len() == 0 {
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l
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} else {
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l.split_at(x).1
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}).collect::<Vec<_>>()
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.join("\n"))
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} else {
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s
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}
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}
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/// get a parent expr if any – this is useful to constrain a lint
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pub fn get_parent_expr<'c>(cx: &'c Context, e: &Expr) -> Option<&'c Expr> {
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let map = &cx.tcx.map;
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let node_id : NodeId = e.id;
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let parent_id : NodeId = map.get_parent_node(node_id);
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if node_id == parent_id { return None; }
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map.find(parent_id).and_then(|node|
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if let NodeExpr(parent) = node { Some(parent) } else { None } )
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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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#[cfg(not(feature="structured_logging"))]
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pub fn span_lint(cx: &Context, lint: &'static Lint, sp: Span, msg: &str) {
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cx.span_lint(lint, sp, msg);
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}
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#[cfg(feature="structured_logging")]
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pub fn span_lint(cx: &Context, lint: &'static Lint, sp: Span, msg: &str) {
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// lint.name / lint.desc is can give details of the lint
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// cx.sess().codemap() has all these nice functions for line/column/snippet details
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// http://doc.rust-lang.org/syntax/codemap/struct.CodeMap.html#method.span_to_string
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cx.span_lint(lint, sp, msg);
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}
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pub fn span_help_and_lint(cx: &Context, lint: &'static Lint, span: Span,
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msg: &str, help: &str) {
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span_lint(cx, lint, span, msg);
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if cx.current_level(lint) != Level::Allow {
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cx.sess().fileline_help(span, help);
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}
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}
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/// return the base type for references and raw pointers
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pub fn walk_ptrs_ty(ty: ty::Ty) -> ty::Ty {
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match ty.sty {
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ty::TyRef(_, ref tm) | ty::TyRawPtr(ref tm) => walk_ptrs_ty(tm.ty),
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_ => ty
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}
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}
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/// Produce a nested chain of if-lets and ifs from the patterns:
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///
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/// if_let_chain! {
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/// [
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/// Some(y) = x,
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/// y.len() == 2,
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/// Some(z) = y,
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/// ],
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/// {
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/// block
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/// }
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/// }
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///
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/// becomes
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///
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/// if let Some(y) = x {
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/// if y.len() == 2 {
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/// if let Some(z) = y {
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/// block
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/// }
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/// }
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/// }
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#[macro_export]
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macro_rules! if_let_chain {
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([let $pat:pat = $expr:expr, $($tt:tt)+], $block:block) => {
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if let $pat = $expr {
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if_let_chain!{ [$($tt)+], $block }
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}
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};
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([let $pat:pat = $expr:expr], $block:block) => {
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if let $pat = $expr {
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$block
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}
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};
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([$expr:expr, $($tt:tt)+], $block:block) => {
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if $expr {
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if_let_chain!{ [$($tt)+], $block }
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}
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};
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([$expr:expr], $block:block) => {
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if $expr {
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$block
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}
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};
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}
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