mirror of
https://github.com/rust-lang/rust-clippy
synced 2024-12-24 03:53:20 +00:00
88 lines
3 KiB
Rust
88 lines
3 KiB
Rust
use clippy_utils::diagnostics::span_lint_and_help;
|
|
use clippy_utils::paths;
|
|
use clippy_utils::ty::match_type;
|
|
use if_chain::if_chain;
|
|
use rustc_hir::{Expr, ExprKind, QPath};
|
|
use rustc_lint::{LateContext, LateLintPass};
|
|
use rustc_session::{declare_lint_pass, declare_tool_lint};
|
|
|
|
declare_clippy_lint! {
|
|
/// ### What it does
|
|
/// Checks for use of File::read_to_end and File::read_to_string.
|
|
///
|
|
/// ### Why is this bad?
|
|
/// `fs::{read, read_to_string}` provide the same functionality when `buf` is empty with fewer imports and no intermediate values.
|
|
/// See also: [fs::read docs](https://doc.rust-lang.org/std/fs/fn.read.html), [fs::read_to_string docs](https://doc.rust-lang.org/std/fs/fn.read_to_string.html)
|
|
///
|
|
/// ### Example
|
|
/// ```rust,no_run
|
|
/// # use std::io::Read;
|
|
/// # use std::fs::File;
|
|
/// let mut f = File::open("foo.txt").unwrap();
|
|
/// let mut bytes = Vec::new();
|
|
/// f.read_to_end(&mut bytes).unwrap();
|
|
/// ```
|
|
/// Can be written more concisely as
|
|
/// ```rust,no_run
|
|
/// # use std::fs;
|
|
/// let mut bytes = fs::read("foo.txt").unwrap();
|
|
/// ```
|
|
#[clippy::version = "1.44.0"]
|
|
pub VERBOSE_FILE_READS,
|
|
restriction,
|
|
"use of `File::read_to_end` or `File::read_to_string`"
|
|
}
|
|
|
|
declare_lint_pass!(VerboseFileReads => [VERBOSE_FILE_READS]);
|
|
|
|
impl<'tcx> LateLintPass<'tcx> for VerboseFileReads {
|
|
fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'tcx>) {
|
|
if is_file_read_to_end(cx, expr) {
|
|
span_lint_and_help(
|
|
cx,
|
|
VERBOSE_FILE_READS,
|
|
expr.span,
|
|
"use of `File::read_to_end`",
|
|
None,
|
|
"consider using `fs::read` instead",
|
|
);
|
|
} else if is_file_read_to_string(cx, expr) {
|
|
span_lint_and_help(
|
|
cx,
|
|
VERBOSE_FILE_READS,
|
|
expr.span,
|
|
"use of `File::read_to_string`",
|
|
None,
|
|
"consider using `fs::read_to_string` instead",
|
|
);
|
|
}
|
|
}
|
|
}
|
|
|
|
fn is_file_read_to_end<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'tcx>) -> bool {
|
|
if_chain! {
|
|
if let ExprKind::MethodCall(method_name, exprs, _) = expr.kind;
|
|
if method_name.ident.as_str() == "read_to_end";
|
|
if let ExprKind::Path(QPath::Resolved(None, _)) = &exprs[0].kind;
|
|
let ty = cx.typeck_results().expr_ty(&exprs[0]);
|
|
if match_type(cx, ty, &paths::FILE);
|
|
then {
|
|
return true
|
|
}
|
|
}
|
|
false
|
|
}
|
|
|
|
fn is_file_read_to_string<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'tcx>) -> bool {
|
|
if_chain! {
|
|
if let ExprKind::MethodCall(method_name, exprs, _) = expr.kind;
|
|
if method_name.ident.as_str() == "read_to_string";
|
|
if let ExprKind::Path(QPath::Resolved(None, _)) = &exprs[0].kind;
|
|
let ty = cx.typeck_results().expr_ty(&exprs[0]);
|
|
if match_type(cx, ty, &paths::FILE);
|
|
then {
|
|
return true
|
|
}
|
|
}
|
|
false
|
|
}
|