New upstream version 1.52.1+dfsg1

[rustc.git] / src / tools / clippy / clippy_utils / src / ptr.rs

diff --git a/src/tools/clippy/clippy_utils/src/ptr.rs b/src/tools/clippy/clippy_utils/src/ptr.rs
new file mode 100644 (file)
index 0000000..df6143e
--- /dev/null
+++ b/src/tools/clippy/clippy_utils/src/ptr.rs
@@ -0,0 +1,82 @@
+use crate::{get_pat_name, match_var, snippet};
+use rustc_hir::intravisit::{walk_expr, NestedVisitorMap, Visitor};
+use rustc_hir::{Body, BodyId, Expr, ExprKind, Param};
+use rustc_lint::LateContext;
+use rustc_middle::hir::map::Map;
+use rustc_span::{Span, Symbol};
+use std::borrow::Cow;
+
+pub fn get_spans(
+    cx: &LateContext<'_>,
+    opt_body_id: Option<BodyId>,
+    idx: usize,
+    replacements: &[(&'static str, &'static str)],
+) -> Option<Vec<(Span, Cow<'static, str>)>> {
+    if let Some(body) = opt_body_id.map(|id| cx.tcx.hir().body(id)) {
+        get_binding_name(&body.params[idx]).map_or_else(
+            || Some(vec![]),
+            |name| extract_clone_suggestions(cx, name, replacements, body),
+        )
+    } else {
+        Some(vec![])
+    }
+}
+
+fn extract_clone_suggestions<'tcx>(
+    cx: &LateContext<'tcx>,
+    name: Symbol,
+    replace: &[(&'static str, &'static str)],
+    body: &'tcx Body<'_>,
+) -> Option<Vec<(Span, Cow<'static, str>)>> {
+    let mut visitor = PtrCloneVisitor {
+        cx,
+        name,
+        replace,
+        spans: vec![],
+        abort: false,
+    };
+    visitor.visit_body(body);
+    if visitor.abort { None } else { Some(visitor.spans) }
+}
+
+struct PtrCloneVisitor<'a, 'tcx> {
+    cx: &'a LateContext<'tcx>,
+    name: Symbol,
+    replace: &'a [(&'static str, &'static str)],
+    spans: Vec<(Span, Cow<'static, str>)>,
+    abort: bool,
+}
+
+impl<'a, 'tcx> Visitor<'tcx> for PtrCloneVisitor<'a, 'tcx> {
+    type Map = Map<'tcx>;
+
+    fn visit_expr(&mut self, expr: &'tcx Expr<'_>) {
+        if self.abort {
+            return;
+        }
+        if let ExprKind::MethodCall(ref seg, _, ref args, _) = expr.kind {
+            if args.len() == 1 && match_var(&args[0], self.name) {
+                if seg.ident.name.as_str() == "capacity" {
+                    self.abort = true;
+                    return;
+                }
+                for &(fn_name, suffix) in self.replace {
+                    if seg.ident.name.as_str() == fn_name {
+                        self.spans
+                            .push((expr.span, snippet(self.cx, args[0].span, "_") + suffix));
+                        return;
+                    }
+                }
+            }
+        }
+        walk_expr(self, expr);
+    }
+
+    fn nested_visit_map(&mut self) -> NestedVisitorMap<Self::Map> {
+        NestedVisitorMap::None
+    }
+}
+
+fn get_binding_name(arg: &Param<'_>) -> Option<Symbol> {
+    get_pat_name(&arg.pat)
+}