5 use rustc::middle::const_val::ConstVal;
6 use rustc_const_eval::ConstContext;
7 use rustc::ty::subst::Substs;
8 use std::collections::HashSet;
10 use syntax::ast::{LitKind, NodeId};
11 use syntax::codemap::{BytePos, Span};
12 use syntax::symbol::InternedString;
13 use utils::{is_expn_of, match_def_path, match_type, opt_def_id, paths, span_help_and_lint, span_lint};
15 /// **What it does:** Checks [regex](https://crates.io/crates/regex) creation
16 /// (with `Regex::new`,`RegexBuilder::new` or `RegexSet::new`) for correct
19 /// **Why is this bad?** This will lead to a runtime panic.
21 /// **Known problems:** None.
30 "invalid regular expressions"
33 /// **What it does:** Checks for trivial [regex](https://crates.io/crates/regex)
34 /// creation (with `Regex::new`, `RegexBuilder::new` or `RegexSet::new`).
36 /// **Why is this bad?** Matching the regex can likely be replaced by `==` or
37 /// `str::starts_with`, `str::ends_with` or `std::contains` or other `str`
40 /// **Known problems:** None.
44 /// Regex::new("^foobar")
49 "trivial regular expressions"
52 /// **What it does:** Checks for usage of `regex!(_)` which (as of now) is
53 /// usually slower than `Regex::new(_)` unless called in a loop (which is a bad
56 /// **Why is this bad?** Performance, at least for now. The macro version is
57 /// likely to catch up long-term, but for now the dynamic version is faster.
59 /// **Known problems:** None.
68 "use of `regex!(_)` instead of `Regex::new(_)`"
71 #[derive(Clone, Default)]
77 impl LintPass for Pass {
78 fn get_lints(&self) -> LintArray {
79 lint_array!(INVALID_REGEX, REGEX_MACRO, TRIVIAL_REGEX)
83 impl<'a, 'tcx> LateLintPass<'a, 'tcx> for Pass {
84 fn check_crate(&mut self, _: &LateContext<'a, 'tcx>, _: &'tcx Crate) {
88 fn check_block(&mut self, cx: &LateContext<'a, 'tcx>, block: &'tcx Block) {
90 if self.last.is_none();
91 if let Some(ref expr) = block.expr;
92 if match_type(cx, cx.tables.expr_ty(expr), &paths::REGEX);
93 if let Some(span) = is_expn_of(expr.span, "regex");
95 if !self.spans.contains(&span) {
100 Please use `Regex::new(_)`, which is faster for now.");
101 self.spans.insert(span);
103 self.last = Some(block.id);
108 fn check_block_post(&mut self, _: &LateContext<'a, 'tcx>, block: &'tcx Block) {
109 if self.last.map_or(false, |id| block.id == id) {
114 fn check_expr(&mut self, cx: &LateContext<'a, 'tcx>, expr: &'tcx Expr) {
116 if let ExprCall(ref fun, ref args) = expr.node;
117 if let ExprPath(ref qpath) = fun.node;
119 if let Some(def_id) = opt_def_id(cx.tables.qpath_def(qpath, fun.hir_id));
121 if match_def_path(cx.tcx, def_id, &paths::REGEX_NEW) ||
122 match_def_path(cx.tcx, def_id, &paths::REGEX_BUILDER_NEW) {
123 check_regex(cx, &args[0], true);
124 } else if match_def_path(cx.tcx, def_id, &paths::REGEX_BYTES_NEW) ||
125 match_def_path(cx.tcx, def_id, &paths::REGEX_BYTES_BUILDER_NEW) {
126 check_regex(cx, &args[0], false);
127 } else if match_def_path(cx.tcx, def_id, &paths::REGEX_SET_NEW) {
128 check_set(cx, &args[0], true);
129 } else if match_def_path(cx.tcx, def_id, &paths::REGEX_BYTES_SET_NEW) {
130 check_set(cx, &args[0], false);
137 #[allow(cast_possible_truncation)]
138 fn str_span(base: Span, s: &str, c: usize) -> Span {
139 let mut si = s.char_indices().skip(c);
141 match (si.next(), si.next()) {
142 (Some((l, _)), Some((h, _))) => {
143 Span::new(base.lo() + BytePos(l as u32), base.lo() + BytePos(h as u32), base.ctxt())
149 fn const_str<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, e: &'tcx Expr) -> Option<InternedString> {
150 let parent_item = cx.tcx.hir.get_parent(e.id);
151 let parent_def_id = cx.tcx.hir.local_def_id(parent_item);
152 let substs = Substs::identity_for_item(cx.tcx, parent_def_id);
153 match ConstContext::new(cx.tcx, cx.param_env.and(substs), cx.tables).eval(e) {
155 val: ConstVal::Str(r),
162 fn is_trivial_regex(s: ®ex_syntax::Expr) -> Option<&'static str> {
163 use regex_syntax::Expr;
166 Expr::Empty | Expr::StartText | Expr::EndText => Some("the regex is unlikely to be useful as it is"),
167 Expr::Literal { .. } => Some("consider using `str::contains`"),
168 Expr::Concat(ref exprs) => match exprs.len() {
169 2 => match (&exprs[0], &exprs[1]) {
170 (&Expr::StartText, &Expr::EndText) => Some("consider using `str::is_empty`"),
171 (&Expr::StartText, &Expr::Literal { .. }) => Some("consider using `str::starts_with`"),
172 (&Expr::Literal { .. }, &Expr::EndText) => Some("consider using `str::ends_with`"),
175 3 => if let (&Expr::StartText, &Expr::Literal { .. }, &Expr::EndText) = (&exprs[0], &exprs[1], &exprs[2]) {
176 Some("consider using `==` on `str`s")
186 fn check_set<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, expr: &'tcx Expr, utf8: bool) {
188 if let ExprAddrOf(_, ref expr) = expr.node;
189 if let ExprArray(ref exprs) = expr.node;
192 check_regex(cx, expr, utf8);
198 fn check_regex<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, expr: &'tcx Expr, utf8: bool) {
199 let builder = regex_syntax::ExprBuilder::new().unicode(utf8);
201 if let ExprLit(ref lit) = expr.node {
202 if let LitKind::Str(ref r, _) = lit.node {
204 match builder.parse(r) {
205 Ok(r) => if let Some(repl) = is_trivial_regex(&r) {
211 &format!("consider using {}", repl),
218 str_span(expr.span, r, e.position()),
219 &format!("regex syntax error: {}", e.description()),
224 } else if let Some(r) = const_str(cx, expr) {
225 match builder.parse(&r) {
226 Ok(r) => if let Some(repl) = is_trivial_regex(&r) {
232 &format!("consider using {}", repl),
240 &format!("regex syntax error on position {}: {}", e.position(), e.description()),