| use crate::consts::{constant, Constant}; |
| use crate::utils::{match_def_path, paths, span_lint, span_lint_and_help}; |
| use if_chain::if_chain; |
| use rustc_ast::ast::{LitKind, StrStyle}; |
| use rustc_data_structures::fx::FxHashSet; |
| use rustc_hir::{BorrowKind, Expr, ExprKind, HirId}; |
| use rustc_lint::{LateContext, LateLintPass}; |
| use rustc_session::{declare_tool_lint, impl_lint_pass}; |
| use rustc_span::source_map::{BytePos, Span}; |
| use std::convert::TryFrom; |
| |
| declare_clippy_lint! { |
| /// **What it does:** Checks [regex](https://crates.io/crates/regex) creation |
| /// (with `Regex::new`,`RegexBuilder::new` or `RegexSet::new`) for correct |
| /// regex syntax. |
| /// |
| /// **Why is this bad?** This will lead to a runtime panic. |
| /// |
| /// **Known problems:** None. |
| /// |
| /// **Example:** |
| /// ```ignore |
| /// Regex::new("|") |
| /// ``` |
| pub INVALID_REGEX, |
| correctness, |
| "invalid regular expressions" |
| } |
| |
| declare_clippy_lint! { |
| /// **What it does:** Checks for trivial [regex](https://crates.io/crates/regex) |
| /// creation (with `Regex::new`, `RegexBuilder::new` or `RegexSet::new`). |
| /// |
| /// **Why is this bad?** Matching the regex can likely be replaced by `==` or |
| /// `str::starts_with`, `str::ends_with` or `std::contains` or other `str` |
| /// methods. |
| /// |
| /// **Known problems:** None. |
| /// |
| /// **Example:** |
| /// ```ignore |
| /// Regex::new("^foobar") |
| /// ``` |
| pub TRIVIAL_REGEX, |
| style, |
| "trivial regular expressions" |
| } |
| |
| #[derive(Clone, Default)] |
| pub struct Regex { |
| spans: FxHashSet<Span>, |
| last: Option<HirId>, |
| } |
| |
| impl_lint_pass!(Regex => [INVALID_REGEX, TRIVIAL_REGEX]); |
| |
| impl<'tcx> LateLintPass<'tcx> for Regex { |
| fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) { |
| if_chain! { |
| if let ExprKind::Call(ref fun, ref args) = expr.kind; |
| if let ExprKind::Path(ref qpath) = fun.kind; |
| if args.len() == 1; |
| if let Some(def_id) = cx.qpath_res(qpath, fun.hir_id).opt_def_id(); |
| then { |
| if match_def_path(cx, def_id, &paths::REGEX_NEW) || |
| match_def_path(cx, def_id, &paths::REGEX_BUILDER_NEW) { |
| check_regex(cx, &args[0], true); |
| } else if match_def_path(cx, def_id, &paths::REGEX_BYTES_NEW) || |
| match_def_path(cx, def_id, &paths::REGEX_BYTES_BUILDER_NEW) { |
| check_regex(cx, &args[0], false); |
| } else if match_def_path(cx, def_id, &paths::REGEX_SET_NEW) { |
| check_set(cx, &args[0], true); |
| } else if match_def_path(cx, def_id, &paths::REGEX_BYTES_SET_NEW) { |
| check_set(cx, &args[0], false); |
| } |
| } |
| } |
| } |
| } |
| |
| #[allow(clippy::cast_possible_truncation)] // truncation very unlikely here |
| #[must_use] |
| fn str_span(base: Span, c: regex_syntax::ast::Span, offset: u16) -> Span { |
| let offset = u32::from(offset); |
| let end = base.lo() + BytePos(u32::try_from(c.end.offset).expect("offset too large") + offset); |
| let start = base.lo() + BytePos(u32::try_from(c.start.offset).expect("offset too large") + offset); |
| assert!(start <= end); |
| Span::new(start, end, base.ctxt()) |
| } |
| |
| fn const_str<'tcx>(cx: &LateContext<'tcx>, e: &'tcx Expr<'_>) -> Option<String> { |
| constant(cx, cx.typeck_results(), e).and_then(|(c, _)| match c { |
| Constant::Str(s) => Some(s), |
| _ => None, |
| }) |
| } |
| |
| fn is_trivial_regex(s: ®ex_syntax::hir::Hir) -> Option<&'static str> { |
| use regex_syntax::hir::Anchor::{EndText, StartText}; |
| use regex_syntax::hir::HirKind::{Alternation, Anchor, Concat, Empty, Literal}; |
| |
| let is_literal = |e: &[regex_syntax::hir::Hir]| e.iter().all(|e| matches!(*e.kind(), Literal(_))); |
| |
| match *s.kind() { |
| Empty | Anchor(_) => Some("the regex is unlikely to be useful as it is"), |
| Literal(_) => Some("consider using `str::contains`"), |
| Alternation(ref exprs) => { |
| if exprs.iter().all(|e| e.kind().is_empty()) { |
| Some("the regex is unlikely to be useful as it is") |
| } else { |
| None |
| } |
| }, |
| Concat(ref exprs) => match (exprs[0].kind(), exprs[exprs.len() - 1].kind()) { |
| (&Anchor(StartText), &Anchor(EndText)) if exprs[1..(exprs.len() - 1)].is_empty() => { |
| Some("consider using `str::is_empty`") |
| }, |
| (&Anchor(StartText), &Anchor(EndText)) if is_literal(&exprs[1..(exprs.len() - 1)]) => { |
| Some("consider using `==` on `str`s") |
| }, |
| (&Anchor(StartText), &Literal(_)) if is_literal(&exprs[1..]) => Some("consider using `str::starts_with`"), |
| (&Literal(_), &Anchor(EndText)) if is_literal(&exprs[1..(exprs.len() - 1)]) => { |
| Some("consider using `str::ends_with`") |
| }, |
| _ if is_literal(exprs) => Some("consider using `str::contains`"), |
| _ => None, |
| }, |
| _ => None, |
| } |
| } |
| |
| fn check_set<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>, utf8: bool) { |
| if_chain! { |
| if let ExprKind::AddrOf(BorrowKind::Ref, _, ref expr) = expr.kind; |
| if let ExprKind::Array(exprs) = expr.kind; |
| then { |
| for expr in exprs { |
| check_regex(cx, expr, utf8); |
| } |
| } |
| } |
| } |
| |
| fn check_regex<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>, utf8: bool) { |
| let mut parser = regex_syntax::ParserBuilder::new() |
| .unicode(true) |
| .allow_invalid_utf8(!utf8) |
| .build(); |
| |
| if let ExprKind::Lit(ref lit) = expr.kind { |
| if let LitKind::Str(ref r, style) = lit.node { |
| let r = &r.as_str(); |
| let offset = if let StrStyle::Raw(n) = style { 2 + n } else { 1 }; |
| match parser.parse(r) { |
| Ok(r) => { |
| if let Some(repl) = is_trivial_regex(&r) { |
| span_lint_and_help(cx, TRIVIAL_REGEX, expr.span, "trivial regex", None, repl); |
| } |
| }, |
| Err(regex_syntax::Error::Parse(e)) => { |
| span_lint( |
| cx, |
| INVALID_REGEX, |
| str_span(expr.span, *e.span(), offset), |
| &format!("regex syntax error: {}", e.kind()), |
| ); |
| }, |
| Err(regex_syntax::Error::Translate(e)) => { |
| span_lint( |
| cx, |
| INVALID_REGEX, |
| str_span(expr.span, *e.span(), offset), |
| &format!("regex syntax error: {}", e.kind()), |
| ); |
| }, |
| Err(e) => { |
| span_lint(cx, INVALID_REGEX, expr.span, &format!("regex syntax error: {}", e)); |
| }, |
| } |
| } |
| } else if let Some(r) = const_str(cx, expr) { |
| match parser.parse(&r) { |
| Ok(r) => { |
| if let Some(repl) = is_trivial_regex(&r) { |
| span_lint_and_help(cx, TRIVIAL_REGEX, expr.span, "trivial regex", None, repl); |
| } |
| }, |
| Err(regex_syntax::Error::Parse(e)) => { |
| span_lint( |
| cx, |
| INVALID_REGEX, |
| expr.span, |
| &format!("regex syntax error on position {}: {}", e.span().start.offset, e.kind()), |
| ); |
| }, |
| Err(regex_syntax::Error::Translate(e)) => { |
| span_lint( |
| cx, |
| INVALID_REGEX, |
| expr.span, |
| &format!("regex syntax error on position {}: {}", e.span().start.offset, e.kind()), |
| ); |
| }, |
| Err(e) => { |
| span_lint(cx, INVALID_REGEX, expr.span, &format!("regex syntax error: {}", e)); |
| }, |
| } |
| } |
| } |