From fe829e075fde48c5337c75c2eb924e8cd2c3c828 Mon Sep 17 00:00:00 2001
From: Elizabeth Mattijsen <liz@raku.rocks>
Date: Wed, 6 Apr 2022 16:27:21 +0200
Subject: [PATCH] Streaming CURF!matching-dist

In the same way as CURS!matching-dist
---
 src/core.c/CompUnit/Repository/FileSystem.pm6 | 29 +++++++++++--------
 1 file changed, 17 insertions(+), 12 deletions(-)

diff --git a/src/core.c/CompUnit/Repository/FileSystem.pm6 b/src/core.c/CompUnit/Repository/FileSystem.pm6
index b759f450441..c9c51326358 100644
--- a/src/core.c/CompUnit/Repository/FileSystem.pm6
+++ b/src/core.c/CompUnit/Repository/FileSystem.pm6
@@ -2,9 +2,9 @@ class CompUnit::Repository::FileSystem
   does CompUnit::Repository::Locally
   does CompUnit::Repository
 {
-    has $!lock = Lock.new;
+    has $!lock;
     has %!loaded; # cache compunit lookup for self.need(...)
-    has %!seen;   # cache distribution lookup for self!matching-dist(...)
+    has $!seen;   # cache distribution lookup for self!matching-dist(...)
     has $!precomp;
     has $!id;
     has $!precomp-stores;
@@ -14,18 +14,23 @@ class CompUnit::Repository::FileSystem
 
     my constant @extensions = <.rakumod .pm6 .pm>;
 
-    method !matching-dist(CompUnit::DependencySpecification $spec) {
-        $!lock.protect: {
-            return $_ with %!seen{~$spec};
-        }
+    method TWEAK(--> Nil) {
+        $!lock := Lock.new;
+        $!seen := nqp::hash;
+    }
 
-        with self.candidates($spec).head {
-            $!lock.protect: {
-                return %!seen{~$spec} //= $_;
-            }
+    # An equivalent of self.candidates($spec).head that caches the best match
+    method !matching-dist(CompUnit::DependencySpecification:D $spec) {
+        $!lock.protect: {
+            nqp::ifnull(
+              nqp::atkey($!seen,~$spec),
+              nqp::if(
+                (my $candidate := self.candidates($spec).head),
+                nqp::bindkey($!seen,~$spec,$candidate),
+                Nil
+              )
+            )
         }
-
-        Nil
     }
 
     method !comp-unit-id($name) {