mirror of
https://github.com/rust-lang/rust-clippy
synced 2024-11-24 21:53:23 +00:00
88 lines
3.5 KiB
Rust
88 lines
3.5 KiB
Rust
use clippy_utils::diagnostics::span_lint_and_sugg;
|
|
use clippy_utils::source::snippet_with_context;
|
|
use clippy_utils::ty::{is_type_diagnostic_item, is_type_lang_item};
|
|
use clippy_utils::visitors::is_expr_unsafe;
|
|
use clippy_utils::{get_parent_node, match_libc_symbol};
|
|
use if_chain::if_chain;
|
|
use rustc_errors::Applicability;
|
|
use rustc_hir::{Block, BlockCheckMode, Expr, ExprKind, LangItem, Node, UnsafeSource};
|
|
use rustc_lint::{LateContext, LateLintPass};
|
|
use rustc_session::{declare_lint_pass, declare_tool_lint};
|
|
use rustc_span::symbol::sym;
|
|
|
|
declare_clippy_lint! {
|
|
/// ### What it does
|
|
/// Checks for usage of `libc::strlen` on a `CString` or `CStr` value,
|
|
/// and suggest calling `as_bytes().len()` or `to_bytes().len()` respectively instead.
|
|
///
|
|
/// ### Why is this bad?
|
|
/// This avoids calling an unsafe `libc` function.
|
|
/// Currently, it also avoids calculating the length.
|
|
///
|
|
/// ### Example
|
|
/// ```rust, ignore
|
|
/// use std::ffi::CString;
|
|
/// let cstring = CString::new("foo").expect("CString::new failed");
|
|
/// let len = unsafe { libc::strlen(cstring.as_ptr()) };
|
|
/// ```
|
|
/// Use instead:
|
|
/// ```rust, no_run
|
|
/// use std::ffi::CString;
|
|
/// let cstring = CString::new("foo").expect("CString::new failed");
|
|
/// let len = cstring.as_bytes().len();
|
|
/// ```
|
|
#[clippy::version = "1.55.0"]
|
|
pub STRLEN_ON_C_STRINGS,
|
|
complexity,
|
|
"using `libc::strlen` on a `CString` or `CStr` value, while `as_bytes().len()` or `to_bytes().len()` respectively can be used instead"
|
|
}
|
|
|
|
declare_lint_pass!(StrlenOnCStrings => [STRLEN_ON_C_STRINGS]);
|
|
|
|
impl<'tcx> LateLintPass<'tcx> for StrlenOnCStrings {
|
|
fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) {
|
|
if_chain! {
|
|
if !expr.span.from_expansion();
|
|
if let ExprKind::Call(func, [recv]) = expr.kind;
|
|
if let ExprKind::Path(path) = &func.kind;
|
|
if let Some(did) = cx.qpath_res(path, func.hir_id).opt_def_id();
|
|
if match_libc_symbol(cx, did, "strlen");
|
|
if let ExprKind::MethodCall(path, self_arg, [], _) = recv.kind;
|
|
if !recv.span.from_expansion();
|
|
if path.ident.name == sym::as_ptr;
|
|
then {
|
|
let ctxt = expr.span.ctxt();
|
|
let span = match get_parent_node(cx.tcx, expr.hir_id) {
|
|
Some(Node::Block(&Block {
|
|
rules: BlockCheckMode::UnsafeBlock(UnsafeSource::UserProvided), span, ..
|
|
}))
|
|
if span.ctxt() == ctxt && !is_expr_unsafe(cx, self_arg) => {
|
|
span
|
|
}
|
|
_ => expr.span,
|
|
};
|
|
|
|
let ty = cx.typeck_results().expr_ty(self_arg).peel_refs();
|
|
let mut app = Applicability::MachineApplicable;
|
|
let val_name = snippet_with_context(cx, self_arg.span, ctxt, "..", &mut app).0;
|
|
let method_name = if is_type_diagnostic_item(cx, ty, sym::cstring_type) {
|
|
"as_bytes"
|
|
} else if is_type_lang_item(cx, ty, LangItem::CStr) {
|
|
"to_bytes"
|
|
} else {
|
|
return;
|
|
};
|
|
|
|
span_lint_and_sugg(
|
|
cx,
|
|
STRLEN_ON_C_STRINGS,
|
|
span,
|
|
"using `libc::strlen` on a `CString` or `CStr` value",
|
|
"try this",
|
|
format!("{val_name}.{method_name}().len()"),
|
|
app,
|
|
);
|
|
}
|
|
}
|
|
}
|
|
}
|