mirror of
https://github.com/rust-lang/rust-clippy
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242 lines
8 KiB
Rust
242 lines
8 KiB
Rust
// Copyright 2014-2018 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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use matches::matches;
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use crate::rustc::hir::intravisit;
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use crate::rustc::hir;
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use crate::rustc::lint::{LateContext, LateLintPass, LintArray, LintPass};
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use crate::rustc::{declare_tool_lint, lint_array};
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use crate::rustc::ty;
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use crate::rustc::hir::def::Def;
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use crate::rustc_data_structures::fx::FxHashSet;
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use crate::syntax::ast;
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use crate::rustc_target::spec::abi::Abi;
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use crate::syntax::source_map::Span;
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use crate::utils::{iter_input_pats, span_lint, type_is_unsafe_function};
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/// **What it does:** Checks for functions with too many parameters.
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///
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/// **Why is this bad?** Functions with lots of parameters are considered bad
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/// style and reduce readability (“what does the 5th parameter mean?”). Consider
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/// grouping some parameters into a new type.
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///
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/// **Known problems:** None.
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///
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/// **Example:**
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/// ```rust
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/// fn foo(x: u32, y: u32, name: &str, c: Color, w: f32, h: f32, a: f32, b:
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/// f32) { .. }
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/// ```
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declare_clippy_lint! {
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pub TOO_MANY_ARGUMENTS,
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complexity,
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"functions with too many arguments"
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}
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/// **What it does:** Checks for public functions that dereferences raw pointer
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/// arguments but are not marked unsafe.
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///
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/// **Why is this bad?** The function should probably be marked `unsafe`, since
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/// for an arbitrary raw pointer, there is no way of telling for sure if it is
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/// valid.
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///
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/// **Known problems:**
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///
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/// * It does not check functions recursively so if the pointer is passed to a
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/// private non-`unsafe` function which does the dereferencing, the lint won't
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/// trigger.
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/// * It only checks for arguments whose type are raw pointers, not raw pointers
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/// got from an argument in some other way (`fn foo(bar: &[*const u8])` or
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/// `some_argument.get_raw_ptr()`).
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///
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/// **Example:**
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/// ```rust
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/// pub fn foo(x: *const u8) { println!("{}", unsafe { *x }); }
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/// ```
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declare_clippy_lint! {
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pub NOT_UNSAFE_PTR_ARG_DEREF,
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correctness,
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"public functions dereferencing raw pointer arguments but not marked `unsafe`"
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}
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#[derive(Copy, Clone)]
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pub struct Functions {
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threshold: u64,
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}
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impl Functions {
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pub fn new(threshold: u64) -> Self {
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Self {
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threshold,
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}
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}
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}
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impl LintPass for Functions {
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fn get_lints(&self) -> LintArray {
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lint_array!(TOO_MANY_ARGUMENTS, NOT_UNSAFE_PTR_ARG_DEREF)
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}
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}
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impl<'a, 'tcx> LateLintPass<'a, 'tcx> for Functions {
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fn check_fn(
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&mut self,
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cx: &LateContext<'a, 'tcx>,
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kind: intravisit::FnKind<'tcx>,
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decl: &'tcx hir::FnDecl,
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body: &'tcx hir::Body,
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span: Span,
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nodeid: ast::NodeId,
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) {
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let is_impl = if let Some(hir::Node::Item(item)) = cx.tcx.hir.find(cx.tcx.hir.get_parent_node(nodeid)) {
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matches!(item.node, hir::ItemKind::Impl(_, _, _, _, Some(_), _, _))
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} else {
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false
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};
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let unsafety = match kind {
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hir::intravisit::FnKind::ItemFn(_, _, hir::FnHeader { unsafety, .. }, _, _) => unsafety,
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hir::intravisit::FnKind::Method(_, sig, _, _) => sig.header.unsafety,
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hir::intravisit::FnKind::Closure(_) => return,
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};
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// don't warn for implementations, it's not their fault
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if !is_impl {
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// don't lint extern functions decls, it's not their fault either
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match kind {
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hir::intravisit::FnKind::Method(_, &hir::MethodSig { header: hir::FnHeader { abi: Abi::Rust, .. }, .. }, _, _) |
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hir::intravisit::FnKind::ItemFn(_, _, hir::FnHeader { abi: Abi::Rust, .. }, _, _) => self.check_arg_number(cx, decl, span),
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_ => {},
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}
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}
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self.check_raw_ptr(cx, unsafety, decl, body, nodeid);
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}
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fn check_trait_item(&mut self, cx: &LateContext<'a, 'tcx>, item: &'tcx hir::TraitItem) {
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if let hir::TraitItemKind::Method(ref sig, ref eid) = item.node {
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// don't lint extern functions decls, it's not their fault
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if sig.header.abi == Abi::Rust {
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self.check_arg_number(cx, &sig.decl, item.span);
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}
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if let hir::TraitMethod::Provided(eid) = *eid {
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let body = cx.tcx.hir.body(eid);
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self.check_raw_ptr(cx, sig.header.unsafety, &sig.decl, body, item.id);
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}
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}
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}
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}
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impl<'a, 'tcx> Functions {
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fn check_arg_number(self, cx: &LateContext<'_, '_>, decl: &hir::FnDecl, span: Span) {
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let args = decl.inputs.len() as u64;
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if args > self.threshold {
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span_lint(
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cx,
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TOO_MANY_ARGUMENTS,
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span,
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&format!("this function has too many arguments ({}/{})", args, self.threshold),
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);
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}
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}
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fn check_raw_ptr(
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self,
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cx: &LateContext<'a, 'tcx>,
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unsafety: hir::Unsafety,
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decl: &'tcx hir::FnDecl,
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body: &'tcx hir::Body,
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nodeid: ast::NodeId,
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) {
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let expr = &body.value;
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if unsafety == hir::Unsafety::Normal && cx.access_levels.is_exported(nodeid) {
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let raw_ptrs = iter_input_pats(decl, body)
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.zip(decl.inputs.iter())
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.filter_map(|(arg, ty)| raw_ptr_arg(arg, ty))
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.collect::<FxHashSet<_>>();
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if !raw_ptrs.is_empty() {
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let tables = cx.tcx.body_tables(body.id());
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let mut v = DerefVisitor {
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cx,
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ptrs: raw_ptrs,
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tables,
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};
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hir::intravisit::walk_expr(&mut v, expr);
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}
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}
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}
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}
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fn raw_ptr_arg(arg: &hir::Arg, ty: &hir::Ty) -> Option<ast::NodeId> {
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if let (&hir::PatKind::Binding(_, id, _, _), &hir::TyKind::Ptr(_)) = (&arg.pat.node, &ty.node) {
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Some(id)
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} else {
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None
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}
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}
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struct DerefVisitor<'a, 'tcx: 'a> {
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cx: &'a LateContext<'a, 'tcx>,
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ptrs: FxHashSet<ast::NodeId>,
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tables: &'a ty::TypeckTables<'tcx>,
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}
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impl<'a, 'tcx> hir::intravisit::Visitor<'tcx> for DerefVisitor<'a, 'tcx> {
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fn visit_expr(&mut self, expr: &'tcx hir::Expr) {
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match expr.node {
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hir::ExprKind::Call(ref f, ref args) => {
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let ty = self.tables.expr_ty(f);
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if type_is_unsafe_function(self.cx, ty) {
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for arg in args {
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self.check_arg(arg);
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}
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}
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},
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hir::ExprKind::MethodCall(_, _, ref args) => {
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let def_id = self.tables.type_dependent_defs()[expr.hir_id].def_id();
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let base_type = self.cx.tcx.type_of(def_id);
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if type_is_unsafe_function(self.cx, base_type) {
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for arg in args {
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self.check_arg(arg);
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}
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}
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},
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hir::ExprKind::Unary(hir::UnDeref, ref ptr) => self.check_arg(ptr),
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_ => (),
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}
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hir::intravisit::walk_expr(self, expr);
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}
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fn nested_visit_map<'this>(&'this mut self) -> intravisit::NestedVisitorMap<'this, 'tcx> {
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intravisit::NestedVisitorMap::None
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}
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}
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impl<'a, 'tcx: 'a> DerefVisitor<'a, 'tcx> {
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fn check_arg(&self, ptr: &hir::Expr) {
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if let hir::ExprKind::Path(ref qpath) = ptr.node {
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if let Def::Local(id) = self.cx.tables.qpath_def(qpath, ptr.hir_id) {
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if self.ptrs.contains(&id) {
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span_lint(
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self.cx,
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NOT_UNSAFE_PTR_ARG_DEREF,
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ptr.span,
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"this public function dereferences a raw pointer but is not marked `unsafe`",
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);
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}
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}
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}
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}
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}
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