Require getting ChangeJson through a factory

The ChangeJson object is not thread safe.  It internally has a mutable
options array and tracks information about accounts in a local cache.

RestViews keep reusing this object in @Singleton views in a way that
is not thread safe.

Change the API to require obtaining the ChangeJson from a Factory
after passing in the Set<ListChangeOptions> the caller wants to use.

Change-Id: I2167b909fd52c10565fc232aefb2f1d27c65c8de

gerrit-server/src/main/java/com/google/gerrit/server/api/changes/ChangeApiImpl.java

@@ -81,7 +81,7 @@ class ChangeApiImpl implements ChangeApi {
   private final GetTopic getTopic;
   private final PutTopic putTopic;
   private final PostReviewers postReviewers;
-  private final Provider<ChangeJson> changeJson;
+  private final ChangeJson.Factory changeJson;
   private final PostHashtags postHashtags;
   private final GetHashtags getHashtags;
   private final ListChangeComments listComments;
@@ -102,7 +102,7 @@ class ChangeApiImpl implements ChangeApi {
       GetTopic getTopic,
       PutTopic putTopic,
       PostReviewers postReviewers,
-      Provider<ChangeJson> changeJson,
+      ChangeJson.Factory changeJson,
       PostHashtags postHashtags,
       GetHashtags getHashtags,
       ListChangeComments listComments,
@@ -276,7 +276,7 @@ class ChangeApiImpl implements ChangeApi {
       if (u.isIdentifiedUser()) {
         ((IdentifiedUser) u).clearStarredChanges();
       }
-      return changeJson.get().addOptions(s).format(change);
+      return changeJson.create(s).format(change);
     } catch (OrmException e) {
       throw new RestApiException("Cannot retrieve change", e);
     }

gerrit-server/src/main/java/com/google/gerrit/server/change/Abandon.java

@@ -53,7 +53,7 @@ public class Abandon implements RestModifyView<ChangeResource, AbandonInput>,
   private final ChangeHooks hooks;
   private final AbandonedSender.Factory abandonedSenderFactory;
   private final Provider<ReviewDb> dbProvider;
-  private final ChangeJson json;
+  private final ChangeJson.Factory json;
   private final ChangeIndexer indexer;
   private final ChangeUpdate.Factory updateFactory;
   private final ChangeMessagesUtil cmUtil;
@@ -62,7 +62,7 @@ public class Abandon implements RestModifyView<ChangeResource, AbandonInput>,
   Abandon(ChangeHooks hooks,
       AbandonedSender.Factory abandonedSenderFactory,
       Provider<ReviewDb> dbProvider,
-      ChangeJson json,
+      ChangeJson.Factory json,
       ChangeIndexer indexer,
       ChangeUpdate.Factory updateFactory,
       ChangeMessagesUtil cmUtil) {
@@ -90,8 +90,7 @@ public class Abandon implements RestModifyView<ChangeResource, AbandonInput>,
       throw new ResourceConflictException("draft changes cannot be abandoned");
     }
     change = abandon(control, input.message, caller.getAccount());
-    ChangeInfo result = json.format(change);
+    return json.create(ChangeJson.NO_OPTIONS).format(change);
-    return result;
   }
 
   public Change abandon(ChangeControl control,

gerrit-server/src/main/java/com/google/gerrit/server/change/ChangeJson.java

@@ -98,8 +98,9 @@ import com.google.gerrit.server.query.change.ChangeData;
 import com.google.gerrit.server.query.change.ChangeData.ChangedLines;
 import com.google.gerrit.server.query.change.QueryResult;
 import com.google.gwtorm.server.OrmException;
-import com.google.inject.Inject;
 import com.google.inject.Provider;
+import com.google.inject.assistedinject.Assisted;
+import com.google.inject.assistedinject.AssistedInject;
 
 import org.eclipse.jgit.lib.ObjectId;
 import org.eclipse.jgit.lib.Repository;
@@ -122,6 +123,12 @@ import java.util.TreeMap;
 
 public class ChangeJson {
   private static final Logger log = LoggerFactory.getLogger(ChangeJson.class);
+  public static final Set<ListChangesOption> NO_OPTIONS =
+      Collections.emptySet();
+
+  public interface Factory {
+    ChangeJson create(Set<ListChangesOption> options);
+  }
 
   private final Provider<ReviewDb> db;
   private final LabelNormalizer labelNormalizer;
@@ -145,7 +152,7 @@ public class ChangeJson {
   private AccountLoader accountLoader;
   private FixInput fix;
 
-  @Inject
+  @AssistedInject
   ChangeJson(
       Provider<ReviewDb> db,
       LabelNormalizer ln,
@@ -163,7 +170,8 @@ public class ChangeJson {
       WebLinks webLinks,
       ChangeMessagesUtil cmUtil,
       Provider<ConsistencyChecker> checkerProvider,
-      ActionJson actionJson) {
+      ActionJson actionJson,
+      @Assisted Set<ListChangesOption> options) {
     this.db = db;
     this.labelNormalizer = ln;
     this.userProvider = user;
@@ -181,17 +189,9 @@ public class ChangeJson {
     this.cmUtil = cmUtil;
     this.checkerProvider = checkerProvider;
     this.actionJson = actionJson;
-    options = EnumSet.noneOf(ListChangesOption.class);
+    this.options = options.isEmpty()
-  }
+        ? EnumSet.noneOf(ListChangesOption.class)
-
+        : EnumSet.copyOf(options);
-  public ChangeJson addOption(ListChangesOption o) {
-    options.add(o);
-    return this;
-  }
-
-  public ChangeJson addOptions(Collection<ListChangesOption> o) {
-    options.addAll(o);
-    return this;
   }
 
   public ChangeJson fix(FixInput fix) {

gerrit-server/src/main/java/com/google/gerrit/server/change/Check.java

@@ -25,19 +25,20 @@ import com.google.gerrit.server.project.ChangeControl;
 import com.google.gwtorm.server.OrmException;
 import com.google.inject.Inject;
 
+import java.util.EnumSet;
+
 public class Check implements RestReadView<ChangeResource>,
     RestModifyView<ChangeResource, FixInput> {
-  private final ChangeJson json;
+  private final ChangeJson.Factory jsonFactory;
 
   @Inject
-  Check(ChangeJson json) {
+  Check(ChangeJson.Factory json) {
-    this.json = json;
+    this.jsonFactory = json;
-    json.addOption(ListChangesOption.CHECK);
   }
 
   @Override
   public Response<ChangeInfo> apply(ChangeResource rsrc) throws OrmException {
-    return Response.withMustRevalidate(json.format(rsrc));
+    return Response.withMustRevalidate(newChangeJson().format(rsrc));
   }
 
   @Override
@@ -49,6 +50,10 @@ public class Check implements RestReadView<ChangeResource>,
         && !ctl.getCurrentUser().getCapabilities().canMaintainServer()) {
       throw new AuthException("Cannot fix change");
     }
-    return Response.withMustRevalidate(json.fix(input).format(rsrc));
+    return Response.withMustRevalidate(newChangeJson().fix(input).format(rsrc));
+  }
+
+  private ChangeJson newChangeJson() {
+    return jsonFactory.create(EnumSet.of(ListChangesOption.CHECK));
   }
 }

gerrit-server/src/main/java/com/google/gerrit/server/change/CherryPick.java

@@ -43,12 +43,12 @@ public class CherryPick implements RestModifyView<RevisionResource, CherryPickIn
     UiAction<RevisionResource> {
   private final Provider<ReviewDb> dbProvider;
   private final CherryPickChange cherryPickChange;
-  private final ChangeJson json;
+  private final ChangeJson.Factory json;
 
   @Inject
   CherryPick(Provider<ReviewDb> dbProvider,
       CherryPickChange cherryPickChange,
-      ChangeJson json) {
+      ChangeJson.Factory json) {
     this.dbProvider = dbProvider;
     this.cherryPickChange = cherryPickChange;
     this.json = json;
@@ -84,7 +84,7 @@ public class CherryPick implements RestModifyView<RevisionResource, CherryPickIn
           cherryPickChange.cherryPick(revision.getChange(),
               revision.getPatchSet(), input.message, refName,
               refControl);
-      return json.format(cherryPickedChangeId);
+      return json.create(ChangeJson.NO_OPTIONS).format(cherryPickedChangeId);
     } catch (InvalidChangeOperationException e) {
       throw new BadRequestException(e.getMessage());
     } catch (MergeException e) {

gerrit-server/src/main/java/com/google/gerrit/server/change/CreateChange.java

@@ -85,7 +85,7 @@ public class CreateChange implements
   private final ProjectsCollection projectsCollection;
   private final CommitValidators.Factory commitValidatorsFactory;
   private final ChangeInserter.Factory changeInserterFactory;
-  private final ChangeJson json;
+  private final ChangeJson.Factory jsonFactory;
   private final ChangeUtil changeUtil;
   private final boolean allowDrafts;
 
@@ -97,7 +97,7 @@ public class CreateChange implements
       ProjectsCollection projectsCollection,
       CommitValidators.Factory commitValidatorsFactory,
       ChangeInserter.Factory changeInserterFactory,
-      ChangeJson json,
+      ChangeJson.Factory json,
       ChangeUtil changeUtil,
       @GerritServerConfig Config config) {
     this.db = db;
@@ -107,7 +107,7 @@ public class CreateChange implements
     this.projectsCollection = projectsCollection;
     this.commitValidatorsFactory = commitValidatorsFactory;
     this.changeInserterFactory = changeInserterFactory;
-    this.json = json;
+    this.jsonFactory = json;
     this.changeUtil = changeUtil;
     this.allowDrafts = config.getBoolean("change", "allowDrafts", true);
   }
@@ -219,6 +219,7 @@ public class CreateChange implements
       ins.setGroups(groups);
       ins.insert();
 
+      ChangeJson json = jsonFactory.create(ChangeJson.NO_OPTIONS);
       return Response.created(json.format(change.getId()));
     }
   }

gerrit-server/src/main/java/com/google/gerrit/server/change/GetChange.java

@@ -23,30 +23,34 @@ import com.google.inject.Inject;
 
 import org.kohsuke.args4j.Option;
 
+import java.util.EnumSet;
+
 public class GetChange implements RestReadView<ChangeResource> {
-  private final ChangeJson json;
+  private final ChangeJson.Factory json;
+  private final EnumSet<ListChangesOption> options =
+      EnumSet.noneOf(ListChangesOption.class);
 
   @Option(name = "-o", usage = "Output options")
   void addOption(ListChangesOption o) {
-    json.addOption(o);
+    options.add(o);
   }
 
   @Option(name = "-O", usage = "Output option flags, in hex")
   void setOptionFlagsHex(String hex) {
-    json.addOptions(ListChangesOption.fromBits(Integer.parseInt(hex, 16)));
+    options.addAll(ListChangesOption.fromBits(Integer.parseInt(hex, 16)));
   }
 
   @Inject
-  GetChange(ChangeJson json) {
+  GetChange(ChangeJson.Factory json) {
     this.json = json;
   }
 
   @Override
   public Response<ChangeInfo> apply(ChangeResource rsrc) throws OrmException {
-    return Response.withMustRevalidate(json.format(rsrc));
+    return Response.withMustRevalidate(json.create(options).format(rsrc));
   }
 
   Response<ChangeInfo> apply(RevisionResource rsrc) throws OrmException {
-    return Response.withMustRevalidate(json.format(rsrc));
+    return Response.withMustRevalidate(json.create(options).format(rsrc));
   }
 }

gerrit-server/src/main/java/com/google/gerrit/server/change/GetCommit.java

@@ -33,14 +33,13 @@ import java.util.concurrent.TimeUnit;
 
 public class GetCommit implements RestReadView<RevisionResource> {
   private final GitRepositoryManager repoManager;
-  private final ChangeJson json;
+  private final ChangeJson.Factory json;
 
   @Option(name = "--links", usage = "Add weblinks")
   private boolean addLinks;
 
   @Inject
-  GetCommit(GitRepositoryManager repoManager,
+  GetCommit(GitRepositoryManager repoManager, ChangeJson.Factory json) {
-      ChangeJson json) {
     this.repoManager = repoManager;
     this.json = json;
   }
@@ -53,8 +52,9 @@ public class GetCommit implements RestReadView<RevisionResource> {
       String rev = rsrc.getPatchSet().getRevision().get();
       RevCommit commit = rw.parseCommit(ObjectId.fromString(rev));
       rw.parseBody(commit);
-      Response<CommitInfo> r = Response.ok(
+      CommitInfo info = json.create(ChangeJson.NO_OPTIONS)
-          json.toCommit(rsrc.getControl(), rw, commit, addLinks));
+          .toCommit(rsrc.getControl(), rw, commit, addLinks);
+      Response<CommitInfo> r = Response.ok(info);
       if (rsrc.isCacheable()) {
         r.caching(CacheControl.PRIVATE(7, TimeUnit.DAYS));
       }

gerrit-server/src/main/java/com/google/gerrit/server/change/Rebase.java

@@ -47,28 +47,29 @@ import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
 import java.io.IOException;
+import java.util.EnumSet;
 
 @Singleton
 public class Rebase implements RestModifyView<RevisionResource, RebaseInput>,
     UiAction<RevisionResource> {
-
   private static final Logger log = LoggerFactory.getLogger(Rebase.class);
+  private static final EnumSet<ListChangesOption> OPTIONS = EnumSet.of(
+      ListChangesOption.CURRENT_REVISION,
+      ListChangesOption.CURRENT_COMMIT);
 
   private final GitRepositoryManager repoManager;
   private final Provider<RebaseChange> rebaseChange;
-  private final ChangeJson json;
+  private final ChangeJson.Factory json;
   private final Provider<ReviewDb> dbProvider;
 
   @Inject
   public Rebase(GitRepositoryManager repoManager,
       Provider<RebaseChange> rebaseChange,
-      ChangeJson json,
+      ChangeJson.Factory json,
       Provider<ReviewDb> dbProvider) {
     this.repoManager = repoManager;
     this.rebaseChange = rebaseChange;
-    this.json = json
+    this.json = json;
-        .addOption(ListChangesOption.CURRENT_REVISION)
-        .addOption(ListChangesOption.CURRENT_COMMIT);
     this.dbProvider = dbProvider;
   }
 
@@ -97,7 +98,7 @@ public class Rebase implements RestModifyView<RevisionResource, RebaseInput>,
       throw new ResourceNotFoundException(change.getId().toString());
     }
 
-    return json.format(change.getId());
+    return json.create(OPTIONS).format(change.getId());
   }
 
   private String findBaseRev(RevWalk rw, RevisionResource rsrc,

gerrit-server/src/main/java/com/google/gerrit/server/change/Restore.java

@@ -53,7 +53,7 @@ public class Restore implements RestModifyView<ChangeResource, RestoreInput>,
   private final ChangeHooks hooks;
   private final RestoredSender.Factory restoredSenderFactory;
   private final Provider<ReviewDb> dbProvider;
-  private final ChangeJson json;
+  private final ChangeJson.Factory json;
   private final ChangeIndexer indexer;
   private final ChangeMessagesUtil cmUtil;
   private final ChangeUpdate.Factory updateFactory;
@@ -62,7 +62,7 @@ public class Restore implements RestModifyView<ChangeResource, RestoreInput>,
   Restore(ChangeHooks hooks,
       RestoredSender.Factory restoredSenderFactory,
       Provider<ReviewDb> dbProvider,
-      ChangeJson json,
+      ChangeJson.Factory json,
       ChangeIndexer indexer,
       ChangeMessagesUtil cmUtil,
       ChangeUpdate.Factory updateFactory) {
@@ -136,8 +136,7 @@ public class Restore implements RestModifyView<ChangeResource, RestoreInput>,
         db.patchSets().get(change.currentPatchSetId()),
         Strings.emptyToNull(input.message),
         dbProvider.get());
-    ChangeInfo result = json.format(change);
+    return json.create(ChangeJson.NO_OPTIONS).format(change);
-    return result;
   }
 
   @Override

gerrit-server/src/main/java/com/google/gerrit/server/change/Revert.java

@@ -44,12 +44,12 @@ import java.io.IOException;
 @Singleton
 public class Revert implements RestModifyView<ChangeResource, RevertInput>,
     UiAction<ChangeResource> {
-  private final ChangeJson json;
+  private final ChangeJson.Factory json;
   private final ChangeUtil changeUtil;
   private final PersonIdent myIdent;
 
   @Inject
-  Revert(ChangeJson json,
+  Revert(ChangeJson.Factory json,
       ChangeUtil changeUtil,
       @GerritPersonIdent PersonIdent myIdent) {
     this.json = json;
@@ -69,18 +69,19 @@ public class Revert implements RestModifyView<ChangeResource, RevertInput>,
       throw new ResourceConflictException("change is " + status(change));
     }
 
+    Change.Id revertedChangeId;
     try {
-      Change.Id revertedChangeId =
+      revertedChangeId = changeUtil.revert(control,
-          changeUtil.revert(control, change.currentPatchSetId(),
+            change.currentPatchSetId(),
-              Strings.emptyToNull(input.message),
+            Strings.emptyToNull(input.message),
-              new PersonIdent(myIdent, TimeUtil.nowTs()), new NoSshInfo());
+            new PersonIdent(myIdent, TimeUtil.nowTs()),
-
+            new NoSshInfo());
-      return json.format(revertedChangeId);
     } catch (InvalidChangeOperationException e) {
       throw new BadRequestException(e.getMessage());
     } catch (NoSuchChangeException e) {
       throw new ResourceNotFoundException(e.getMessage());
     }
+    return json.create(ChangeJson.NO_OPTIONS).format(revertedChangeId);
   }
 
   @Override

gerrit-server/src/main/java/com/google/gerrit/server/change/Submit.java

@@ -472,12 +472,12 @@ public class Submit implements RestModifyView<RevisionResource, SubmitInput>,
       RestModifyView<ChangeResource, SubmitInput> {
     private final Provider<ReviewDb> dbProvider;
     private final Submit submit;
-    private final ChangeJson json;
+    private final ChangeJson.Factory json;
 
     @Inject
     CurrentRevision(Provider<ReviewDb> dbProvider,
         Submit submit,
-        ChangeJson json) {
+        ChangeJson.Factory json) {
       this.dbProvider = dbProvider;
       this.submit = submit;
       this.json = json;
@@ -495,8 +495,9 @@ public class Submit implements RestModifyView<RevisionResource, SubmitInput>,
       } else if (!rsrc.getControl().isPatchVisible(ps, dbProvider.get())) {
         throw new AuthException("current revision not accessible");
       }
+
       Output out = submit.apply(new RevisionResource(rsrc, ps), input);
-      return json.format(out.change);
+      return json.create(ChangeJson.NO_OPTIONS).format(out.change);
     }
   }
 }

gerrit-server/src/main/java/com/google/gerrit/server/change/SubmittedTogether.java

@@ -40,13 +40,12 @@ public class SubmittedTogether implements RestReadView<ChangeResource> {
   private static final Logger log = LoggerFactory.getLogger(
       SubmittedTogether.class);
 
-  private final ChangeJson json;
+  private final ChangeJson.Factory json;
-
   private final Provider<ReviewDb> dbProvider;
   private final MergeSuperSet mergeSuperSet;
 
   @Inject
-  SubmittedTogether(ChangeJson json,
+  SubmittedTogether(ChangeJson.Factory json,
       Provider<ReviewDb> dbProvider,
       MergeSuperSet mergeSuperSet) {
     this.json = json;
@@ -61,12 +60,12 @@ public class SubmittedTogether implements RestReadView<ChangeResource> {
     try {
       ChangeSet cs = mergeSuperSet.completeChangeSet(dbProvider.get(),
           ChangeSet.create(resource.getChange()));
-      json.addOptions(EnumSet.of(
+      return json.create(EnumSet.of(
           ListChangesOption.CURRENT_REVISION,
           ListChangesOption.CURRENT_COMMIT,
           ListChangesOption.DETAILED_LABELS,
-          ListChangesOption.LABELS));
+          ListChangesOption.LABELS))
-      return json.format(cs.ids());
+        .format(cs.ids());
     } catch (OrmException | IOException e) {
       log.error("Error on getting a ChangeSet", e);
       throw e;

gerrit-server/src/main/java/com/google/gerrit/server/config/GerritGlobalModule.java

@@ -69,6 +69,7 @@ import com.google.gerrit.server.auth.AuthBackend;
 import com.google.gerrit.server.auth.UniversalAuthBackend;
 import com.google.gerrit.server.avatar.AvatarProvider;
 import com.google.gerrit.server.cache.CacheRemovalListener;
+import com.google.gerrit.server.change.ChangeJson;
 import com.google.gerrit.server.change.ChangeKindCacheImpl;
 import com.google.gerrit.server.change.MergeabilityCacheImpl;
 import com.google.gerrit.server.events.EventFactory;
@@ -186,6 +187,7 @@ public class GerritGlobalModule extends FactoryModule {
     factory(AddReviewerSender.Factory.class);
     factory(CapabilityControl.Factory.class);
     factory(ChangeData.Factory.class);
+    factory(ChangeJson.Factory.class);
     factory(CreateChangeSender.Factory.class);
     factory(GroupDetailFactory.Factory.class);
     factory(GroupInfoCacheFactory.Factory.class);

gerrit-server/src/main/java/com/google/gerrit/server/query/change/QueryChanges.java

@@ -38,7 +38,7 @@ import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 
 public class QueryChanges implements RestReadView<TopLevelResource> {
-  private final ChangeJson json;
+  private final ChangeJson.Factory json;
   private final ChangeQueryBuilder qb;
   private final QueryProcessor imp;
   private final Provider<CurrentUser> user;
@@ -68,7 +68,7 @@ public class QueryChanges implements RestReadView<TopLevelResource> {
   }
 
   @Inject
-  QueryChanges(ChangeJson json,
+  QueryChanges(ChangeJson.Factory json,
       ChangeQueryBuilder qb,
       QueryProcessor qp,
       Provider<CurrentUser> user) {
@@ -141,7 +141,7 @@ public class QueryChanges implements RestReadView<TopLevelResource> {
       QueryParseException {
     int cnt = queries.size();
     List<QueryResult> results = imp.queryChanges(qb.parse(queries));
-    List<List<ChangeInfo>> res = json.addOptions(options)
+    List<List<ChangeInfo>> res = json.create(options)
         .formatQueryResults(results);
     for (int n = 0; n < cnt; n++) {
       List<ChangeInfo> info = res.get(n);