From: Eh2406 <YeomanYaacov@gmail.com>
Date: Thu, 5 Apr 2018 20:34:49 +0000 (-0400)
Subject: use more Rc in the part of resolver that gets cloned a lot
X-Git-Tag: archive/raspbian/0.35.0-2+rpi1~3^2^2^2^2^2^2^2~22^2~1^2~93^2~1
X-Git-Url: https://dgit.raspbian.org/?a=commitdiff_plain;h=736c3d7bb79fb0b29c479e3191e5cad27f9872fb;p=cargo.git

use more Rc in the part of resolver that gets cloned a lot
---

diff --git a/src/cargo/core/resolver/context.rs b/src/cargo/core/resolver/context.rs
index b2b49a6b5..f132463e3 100644
--- a/src/cargo/core/resolver/context.rs
+++ b/src/cargo/core/resolver/context.rs
@@ -23,7 +23,7 @@ pub struct Context {
     //       switch to persistent hash maps if we can at some point or otherwise
     //       make these much cheaper to clone in general.
     pub activations: Activations,
-    pub resolve_features: HashMap<PackageId, HashSet<InternedString>>,
+    pub resolve_features: HashMap<PackageId, Rc<HashSet<InternedString>>>,
     pub links: HashMap<InternedString, PackageId>,
 
     // These are two cheaply-cloneable lists (O(1) clone) which are effectively
@@ -36,6 +36,8 @@ pub struct Context {
     pub warnings: RcList<String>,
 }
 
+pub type Activations = HashMap<(InternedString, SourceId), Rc<Vec<Summary>>>;
+
 impl Context {
     pub fn new() -> Context {
         Context {
@@ -246,10 +248,13 @@ impl Context {
 
             let set = self.resolve_features
                 .entry(pkgid.clone())
-                .or_insert_with(HashSet::new);
+                .or_insert_with(|| Rc::new(HashSet::new()));
+
+            let mut inner: HashSet<_> = (**set).clone();
             for feature in reqs.used {
-                set.insert(InternedString::new(feature));
+                inner.insert(InternedString::new(feature));
             }
+            *set = Rc::new(inner);
         }
 
         Ok(ret)
@@ -405,5 +410,3 @@ impl<'r> Requirements<'r> {
         }
     }
 }
-
-pub type Activations = HashMap<(InternedString, SourceId), Rc<Vec<Summary>>>;