Adding upstream version 1.64.0+dfsg1.upstream/1.64.0+dfsg1

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 88 insertions, 0 deletions

diff --git a/src/tools/clippy/clippy_lints/src/strlen_on_c_strings.rs b/src/tools/clippy/clippy_lints/src/strlen_on_c_strings.rs
new file mode 100644
index 000000000..7bc9cf742
--- /dev/null
+++ b/src/tools/clippy/clippy_lints/src/strlen_on_c_strings.rs
@@ -0,0 +1,88 @@
+use clippy_utils::diagnostics::span_lint_and_sugg;
+use clippy_utils::source::snippet_with_context;
+use clippy_utils::ty::is_type_diagnostic_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, 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_diagnostic_item(cx, ty, sym::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!("{}.{}().len()", val_name, method_name),
+                    app,
+                );
+            }
+        }
+    }
+}