use rustc::hir::*;
use rustc::lint::*;
+use rustc::{declare_lint, lint_array};
+use if_chain::if_chain;
use rustc::ty;
use syntax::ast::{Name, UintTy};
-use utils::{contains_name, match_type, paths, single_segment_path, snippet, span_lint_and_sugg, walk_ptrs_ty};
+use crate::utils::{contains_name, get_pat_name, match_type, paths, single_segment_path, snippet, span_lint_and_sugg,
+ walk_ptrs_ty};
/// **What it does:** Checks for naive byte counts
///
/// ```rust
/// &my_data.filter(|&x| x == 0u8).count() // use bytecount::count instead
/// ```
-declare_lint! {
+declare_clippy_lint! {
pub NAIVE_BYTECOUNT,
- Warn,
+ perf,
"use of naive `<slice>.filter(|&x| x == y).count()` to count byte values"
}
impl<'a, 'tcx> LateLintPass<'a, 'tcx> for ByteCount {
fn check_expr(&mut self, cx: &LateContext, expr: &Expr) {
- if_let_chain!([
- let ExprMethodCall(ref count, _, ref count_args) = expr.node,
- count.name == "count",
- count_args.len() == 1,
- let ExprMethodCall(ref filter, _, ref filter_args) = count_args[0].node,
- filter.name == "filter",
- filter_args.len() == 2,
- let ExprClosure(_, _, body_id, _, _) = filter_args[1].node,
- ], {
- let body = cx.tcx.hir.body(body_id);
- if_let_chain!([
- body.arguments.len() == 1,
- let Some(argname) = get_pat_name(&body.arguments[0].pat),
- let ExprBinary(ref op, ref l, ref r) = body.value.node,
- op.node == BiEq,
- match_type(cx,
- walk_ptrs_ty(cx.tables.expr_ty(&filter_args[0])),
- &paths::SLICE_ITER),
- ], {
- let needle = match get_path_name(l) {
- Some(name) if check_arg(name, argname, r) => r,
- _ => match get_path_name(r) {
- Some(name) if check_arg(name, argname, l) => l,
- _ => { return; }
+ if_chain! {
+ if let ExprKind::MethodCall(ref count, _, ref count_args) = expr.node;
+ if count.ident.name == "count";
+ if count_args.len() == 1;
+ if let ExprKind::MethodCall(ref filter, _, ref filter_args) = count_args[0].node;
+ if filter.ident.name == "filter";
+ if filter_args.len() == 2;
+ if let ExprKind::Closure(_, _, body_id, _, _) = filter_args[1].node;
+ then {
+ let body = cx.tcx.hir.body(body_id);
+ if_chain! {
+ if body.arguments.len() == 1;
+ if let Some(argname) = get_pat_name(&body.arguments[0].pat);
+ if let ExprKind::Binary(ref op, ref l, ref r) = body.value.node;
+ if op.node == BinOpKind::Eq;
+ if match_type(cx,
+ walk_ptrs_ty(cx.tables.expr_ty(&filter_args[0])),
+ &paths::SLICE_ITER);
+ then {
+ let needle = match get_path_name(l) {
+ Some(name) if check_arg(name, argname, r) => r,
+ _ => match get_path_name(r) {
+ Some(name) if check_arg(name, argname, l) => l,
+ _ => { return; }
+ }
+ };
+ if ty::TyUint(UintTy::U8) != walk_ptrs_ty(cx.tables.expr_ty(needle)).sty {
+ return;
+ }
+ let haystack = if let ExprKind::MethodCall(ref path, _, ref args) =
+ filter_args[0].node {
+ let p = path.ident.name;
+ if (p == "iter" || p == "iter_mut") && args.len() == 1 {
+ &args[0]
+ } else {
+ &filter_args[0]
+ }
+ } else {
+ &filter_args[0]
+ };
+ span_lint_and_sugg(cx,
+ NAIVE_BYTECOUNT,
+ expr.span,
+ "You appear to be counting bytes the naive way",
+ "Consider using the bytecount crate",
+ format!("bytecount::count({}, {})",
+ snippet(cx, haystack.span, ".."),
+ snippet(cx, needle.span, "..")));
}
};
- if ty::TyUint(UintTy::U8) != walk_ptrs_ty(cx.tables.expr_ty(needle)).sty {
- return;
- }
- let haystack = if let ExprMethodCall(ref path, _, ref args) =
- filter_args[0].node {
- let p = path.name;
- if (p == "iter" || p == "iter_mut") && args.len() == 1 {
- &args[0]
- } else {
- &filter_args[0]
- }
- } else {
- &filter_args[0]
- };
- span_lint_and_sugg(cx,
- NAIVE_BYTECOUNT,
- expr.span,
- "You appear to be counting bytes the naive way",
- "Consider using the bytecount crate",
- format!("bytecount::count({}, {})",
- snippet(cx, haystack.span, ".."),
- snippet(cx, needle.span, "..")));
- });
- });
+ }
+ };
}
}
name == arg && !contains_name(name, needle)
}
-fn get_pat_name(pat: &Pat) -> Option<Name> {
- match pat.node {
- PatKind::Binding(_, _, ref spname, _) => Some(spname.node),
- PatKind::Path(ref qpath) => single_segment_path(qpath).map(|ps| ps.name),
- PatKind::Box(ref p) | PatKind::Ref(ref p, _) => get_pat_name(&*p),
- _ => None,
- }
-}
-
fn get_path_name(expr: &Expr) -> Option<Name> {
match expr.node {
- ExprBox(ref e) | ExprAddrOf(_, ref e) | ExprUnary(UnOp::UnDeref, ref e) => get_path_name(e),
- ExprBlock(ref b) => if b.stmts.is_empty() {
+ ExprKind::Box(ref e) | ExprKind::AddrOf(_, ref e) | ExprKind::Unary(UnOp::UnDeref, ref e) => get_path_name(e),
+ ExprKind::Block(ref b, _) => if b.stmts.is_empty() {
b.expr.as_ref().and_then(|p| get_path_name(p))
} else {
None
},
- ExprPath(ref qpath) => single_segment_path(qpath).map(|ps| ps.name),
+ ExprKind::Path(ref qpath) => single_segment_path(qpath).map(|ps| ps.ident.name),
_ => None,
}
}
projects / rust.git / blobdiff