Re-landing of "replace TrySync with Metadata".

runtime/vm/fixed_cache_test.cc

 // Copyright (c) 2017, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include <string.h>
 #include "platform/assert.h"
 #include "vm/fixed_cache.h"
 #include "vm/unit_test.h"
 
 namespace dart {
@@ skipping 26 matching lines @@
   EXPECT(strcmp(*cache.Lookup(40), "c") == 0);
   EXPECT(strcmp(*cache.Lookup(25), "bc") == 0);
   // Non-existent - front, middle, end.
   EXPECT(cache.Lookup(1) == NULL);
   EXPECT(cache.Lookup(35) == NULL);
   EXPECT(cache.Lookup(50) == NULL);
 }
 
 
 struct Resource {
-  Resource() : id(0), stuff(NULL) {}
-  explicit Resource(int id_) : id(id_), stuff(new int) {}
+  Resource() : id(0) { copies++; }
+  explicit Resource(int id_) : id(id_) { copies++; }
+
+  Resource(const Resource& r) {
+    id = r.id;
+    copies++;
+  }
+
+  Resource& operator=(const Resource& r) {
+    id = r.id;
+    return *this;
+  }
+
+  ~Resource() { copies--; }
 
   int id;
-  int* stuff;
+  static int copies;
 };
 
-static void freeResource(Resource* res) {
-  delete res->stuff;
-}
+int Resource::copies = 0;
 
+UNIT_TEST_CASE(FixedCacheFullResource) {
+  {
+    FixedCache<int, Resource, 6> cache;
+    cache.Insert(10, Resource(2));
+    cache.Insert(20, Resource(4));
+    cache.Insert(40, Resource(16));
+    cache.Insert(30, Resource(8));
+    EXPECT(cache.Lookup(40)->id == 16);
+    EXPECT(cache.Lookup(5) == NULL);
+    EXPECT(cache.Lookup(0) == NULL);
+    // Insert in the front, middle.
+    cache.Insert(5, Resource(1));
+    cache.Insert(15, Resource(3));
+    cache.Insert(25, Resource(6));
+    // 40 got removed by shifting.
+    EXPECT(cache.Lookup(40) == NULL);
+    EXPECT(cache.Lookup(5)->id == 1);
+    EXPECT(cache.Lookup(15)->id == 3);
+    EXPECT(cache.Lookup(25)->id == 6);
 
-UNIT_TEST_CASE(FixedCacheFullDeleter) {
-  FixedCache<int, Resource, 6> cache(freeResource);
-  cache.Insert(10, Resource(2));
-  cache.Insert(20, Resource(4));
-  cache.Insert(40, Resource(16));
-  cache.Insert(30, Resource(8));
-  EXPECT(cache.Lookup(40)->id == 16);
-  EXPECT(cache.Lookup(5) == NULL);
-  EXPECT(cache.Lookup(0) == NULL);
-  // Insert in the front, middle.
-  cache.Insert(5, Resource(1));
-  cache.Insert(15, Resource(3));
-  cache.Insert(25, Resource(6));
-  // 40 got removed by shifting.
-  EXPECT(cache.Lookup(40) == NULL);
-  EXPECT(cache.Lookup(5)->id == 1);
-  EXPECT(cache.Lookup(15)->id == 3);
-  EXPECT(cache.Lookup(25)->id == 6);
-
-  // Insert at end top - 30 gets replaced by 40.
-  cache.Insert(40, Resource(16));
-  EXPECT(cache.Lookup(40)->id == 16);
-  EXPECT(cache.Lookup(30) == NULL);
+    // Insert at end top - 30 gets replaced by 40.
+    cache.Insert(40, Resource(16));
+    EXPECT(cache.Lookup(40)->id == 16);
+    EXPECT(cache.Lookup(30) == NULL);
+  }
+  EXPECT(Resource::copies == 0);
 }
 
 }  // namespace dart