Cache resourcePath in PermissionBackend

resourcePath() is used to deduplicate PermissionBackendConditions and
possible executed a number of times in equality checks. This commit adds
some local caching to reduce garbage.

Change-Id: I10af9143137efcc3bd0ac1e152a57614a4dc6231

java/com/google/gerrit/server/permissions/ChangeControl.java

@@ -283,6 +283,7 @@ class ChangeControl {
   private class ForChangeImpl extends ForChange {
     private ChangeData cd;
     private Map<String, PermissionRange> labels;
+    private String resourcePath;
 
     ForChangeImpl(@Nullable ChangeData cd, @Nullable Provider<ReviewDb> db) {
       this.cd = cd;
@@ -320,9 +321,13 @@ class ChangeControl {
 
     @Override
     public String resourcePath() {
-      return String.format(
-          "/projects/%s/+changes/%s",
-          getProjectControl().getProjectState().getName(), changeData().getId().get());
+      if (resourcePath == null) {
+        resourcePath =
+            String.format(
+                "/projects/%s/+changes/%s",
+                getProjectControl().getProjectState().getName(), changeData().getId().get());
+      }
+      return resourcePath;
     }
 
     @Override

java/com/google/gerrit/server/permissions/ProjectControl.java

@@ -312,6 +312,8 @@ class ProjectControl {
   }
 
   private class ForProjectImpl extends ForProject {
+    private String resourcePath;
+
     @Override
     public CurrentUser user() {
       return getUser();
@@ -324,7 +326,10 @@ class ProjectControl {
 
     @Override
     public String resourcePath() {
-      return "/projects/" + getProjectState().getName();
+      if (resourcePath == null) {
+        resourcePath = "/projects/" + getProjectState().getName();
+      }
+      return resourcePath;
     }
 
     @Override

java/com/google/gerrit/server/permissions/RefControl.java

@@ -431,6 +431,8 @@ class RefControl {
   }
 
   private class ForRefImpl extends ForRef {
+    private String resourcePath;
+
     @Override
     public CurrentUser user() {
       return getUser();
@@ -443,8 +445,12 @@ class RefControl {
 
     @Override
     public String resourcePath() {
-      return String.format(
-          "/projects/%s/+refs/%s", getProjectControl().getProjectState().getName(), refName);
+      if (resourcePath == null) {
+        resourcePath =
+            String.format(
+                "/projects/%s/+refs/%s", getProjectControl().getProjectState().getName(), refName);
+      }
+      return resourcePath;
     }
 
     @Override