| use crate::consts::{constant, Constant}; |
| use crate::utils::{is_expn_of, match_def_path, match_type, paths, span_help_and_lint, span_lint}; |
| use if_chain::if_chain; |
| use regex_syntax; |
| use rustc::hir::*; |
| use rustc::lint::{LateContext, LateLintPass, LintArray, LintPass}; |
| use rustc::{declare_tool_lint, lint_array}; |
| use rustc_data_structures::fx::FxHashSet; |
| use std::convert::TryFrom; |
| use syntax::ast::{LitKind, StrStyle}; |
| use syntax::source_map::{BytePos, Span}; |
| |
| 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" |
| } |
| |
| declare_clippy_lint! { |
| /// **What it does:** Checks for usage of `regex!(_)` which (as of now) is |
| /// usually slower than `Regex::new(_)` unless called in a loop (which is a bad |
| /// idea anyway). |
| /// |
| /// **Why is this bad?** Performance, at least for now. The macro version is |
| /// likely to catch up long-term, but for now the dynamic version is faster. |
| /// |
| /// **Known problems:** None. |
| /// |
| /// **Example:** |
| /// ```ignore |
| /// regex!("foo|bar") |
| /// ``` |
| pub REGEX_MACRO, |
| style, |
| "use of `regex!(_)` instead of `Regex::new(_)`" |
| } |
| |
| #[derive(Clone, Default)] |
| pub struct Pass { |
| spans: FxHashSet<Span>, |
| last: Option<HirId>, |
| } |
| |
| impl LintPass for Pass { |
| fn get_lints(&self) -> LintArray { |
| lint_array!(INVALID_REGEX, REGEX_MACRO, TRIVIAL_REGEX) |
| } |
| |
| fn name(&self) -> &'static str { |
| "Regex" |
| } |
| } |
| |
| impl<'a, 'tcx> LateLintPass<'a, 'tcx> for Pass { |
| fn check_crate(&mut self, _: &LateContext<'a, 'tcx>, _: &'tcx Crate) { |
| self.spans.clear(); |
| } |
| |
| fn check_block(&mut self, cx: &LateContext<'a, 'tcx>, block: &'tcx Block) { |
| if_chain! { |
| if self.last.is_none(); |
| if let Some(ref expr) = block.expr; |
| if match_type(cx, cx.tables.expr_ty(expr), &paths::REGEX); |
| if let Some(span) = is_expn_of(expr.span, "regex"); |
| then { |
| if !self.spans.contains(&span) { |
| span_lint(cx, |
| REGEX_MACRO, |
| span, |
| "`regex!(_)` found. \ |
| Please use `Regex::new(_)`, which is faster for now."); |
| self.spans.insert(span); |
| } |
| self.last = Some(block.hir_id); |
| } |
| } |
| } |
| |
| fn check_block_post(&mut self, _: &LateContext<'a, 'tcx>, block: &'tcx Block) { |
| if self.last.map_or(false, |id| block.hir_id == id) { |
| self.last = None; |
| } |
| } |
| |
| fn check_expr(&mut self, cx: &LateContext<'a, 'tcx>, expr: &'tcx Expr) { |
| if_chain! { |
| if let ExprKind::Call(ref fun, ref args) = expr.node; |
| if let ExprKind::Path(ref qpath) = fun.node; |
| if args.len() == 1; |
| if let Some(def_id) = cx.tables.qpath_def(qpath, fun.hir_id).opt_def_id(); |
| then { |
| if match_def_path(cx.tcx, def_id, &paths::REGEX_NEW) || |
| match_def_path(cx.tcx, def_id, &paths::REGEX_BUILDER_NEW) { |
| check_regex(cx, &args[0], true); |
| } else if match_def_path(cx.tcx, def_id, &paths::REGEX_BYTES_NEW) || |
| match_def_path(cx.tcx, def_id, &paths::REGEX_BYTES_BUILDER_NEW) { |
| check_regex(cx, &args[0], false); |
| } else if match_def_path(cx.tcx, def_id, &paths::REGEX_SET_NEW) { |
| check_set(cx, &args[0], true); |
| } else if match_def_path(cx.tcx, def_id, &paths::REGEX_BYTES_SET_NEW) { |
| check_set(cx, &args[0], false); |
| } |
| } |
| } |
| } |
| } |
| |
| #[allow(clippy::cast_possible_truncation)] // truncation very unlikely here |
| 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<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, e: &'tcx Expr) -> Option<String> { |
| constant(cx, cx.tables, 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::*; |
| use regex_syntax::hir::HirKind::*; |
| |
| let is_literal = |e: &[regex_syntax::hir::Hir]| { |
| e.iter().all(|e| match *e.kind() { |
| Literal(_) => true, |
| _ => false, |
| }) |
| }; |
| |
| 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<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, expr: &'tcx Expr, utf8: bool) { |
| if_chain! { |
| if let ExprKind::AddrOf(_, ref expr) = expr.node; |
| if let ExprKind::Array(ref exprs) = expr.node; |
| then { |
| for expr in exprs { |
| check_regex(cx, expr, utf8); |
| } |
| } |
| } |
| } |
| |
| fn check_regex<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, expr: &'tcx Expr, utf8: bool) { |
| let mut parser = regex_syntax::ParserBuilder::new() |
| .unicode(utf8) |
| .allow_invalid_utf8(!utf8) |
| .build(); |
| |
| if let ExprKind::Lit(ref lit) = expr.node { |
| 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_help_and_lint(cx, TRIVIAL_REGEX, expr.span, "trivial regex", 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_help_and_lint(cx, TRIVIAL_REGEX, expr.span, "trivial regex", 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)); |
| }, |
| } |
| } |
| } |