ExportReviewNotes: Load changes from notedb if enabled

This requires a new method in ChangeNotes.Factory to get changes notes
by project.

CreateReviewNotes#createCodeReviewNote needs the change notes, so pass
in the change notes, instead of passing in the change and loading
the change notes a second time.

ChangeNotes.Factory doesn't support batch loading of changes yet. Due
to this batch loading changes still accesses the database directly
when notedb is disabled. For changes loaded in such a batch we want to
instantiate ChangeNotes without reloading the change. Add a special
method for this to ChangeNotes.Factory. This method is not supposed to
be used when notedb is enabled.

Change-Id: Ifd01276a607fb5ab4a36322112d0b7aaa0f0ff70
Signed-off-by: Edwin Kempin <ekempin@google.com>

gerrit-server/src/main/java/com/google/gerrit/server/git/ScanningChangeCacheImpl.java

@@ -16,9 +16,11 @@ package com.google.gerrit.server.git;
 
 import static com.google.gerrit.server.git.SearchingChangeCacheImpl.ID_CACHE;
 
+import com.google.common.base.Function;
 import com.google.common.cache.CacheLoader;
 import com.google.common.cache.LoadingCache;
 import com.google.common.collect.Iterables;
+import com.google.common.collect.Lists;
 import com.google.gerrit.reviewdb.client.Change;
 import com.google.gerrit.reviewdb.client.Project;
 import com.google.gerrit.reviewdb.client.RefNames;
@@ -120,7 +122,7 @@ public class ScanningChangeCacheImpl implements ChangeCache {
       return scanDb(repo, db);
     }
 
-    return scanNotedb(notesFactory, repo, db, project);
+    return scanChangesFromNotedb(notesFactory, repo, db, project);
   }
 
   public static List<Change> scanDb(Repository repo, ReviewDb db)
@@ -143,18 +145,30 @@ public class ScanningChangeCacheImpl implements ChangeCache {
     return changes;
   }
 
-  public static List<Change> scanNotedb(ChangeNotes.Factory notesFactory,
+  private static List<Change> scanChangesFromNotedb(
+      ChangeNotes.Factory notesFactory, Repository repo, ReviewDb db,
+      Project.NameKey project) throws OrmException, IOException {
+    List<ChangeNotes> changeNotes = scanNotedb(notesFactory, repo, db, project);
+    return Lists.transform(changeNotes, new Function<ChangeNotes, Change>() {
+      @Override
+      public Change apply(ChangeNotes notes) {
+        return notes.getChange();
+      }
+    });
+  }
+
+  public static List<ChangeNotes> scanNotedb(ChangeNotes.Factory notesFactory,
       Repository repo, ReviewDb db, Project.NameKey project)
           throws OrmException, IOException {
     Map<String, Ref> refs =
         repo.getRefDatabase().getRefs(RefNames.REFS_CHANGES);
-    List<Change> changes = new ArrayList<>(refs.size());
+    List<ChangeNotes> changeNotes = new ArrayList<>(refs.size());
     for (Ref r : refs.values()) {
       Change.Id id = Change.Id.fromRef(r.getName());
       if (id != null) {
-        changes.add(notesFactory.create(db, project, id).getChange());
+        changeNotes.add(notesFactory.create(db, project, id));
       }
     }
-    return changes;
+    return changeNotes;
   }
 }

gerrit-server/src/main/java/com/google/gerrit/server/notedb/ChangeNotes.java

@@ -20,7 +20,9 @@ import static com.google.gerrit.server.notedb.ChangeNoteUtil.GERRIT_PLACEHOLDER_
 
 import com.google.common.annotations.VisibleForTesting;
 import com.google.common.base.Function;
+import com.google.common.base.Predicate;
 import com.google.common.base.Strings;
+import com.google.common.collect.ArrayListMultimap;
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableListMultimap;
 import com.google.common.collect.ImmutableMap;
@@ -28,6 +30,7 @@ import com.google.common.collect.ImmutableSet;
 import com.google.common.collect.ImmutableSetMultimap;
 import com.google.common.collect.ImmutableSortedMap;
 import com.google.common.collect.ImmutableSortedSet;
+import com.google.common.collect.ListMultimap;
 import com.google.common.collect.Ordering;
 import com.google.common.primitives.Ints;
 import com.google.gerrit.common.data.SubmitRecord;
@@ -45,7 +48,9 @@ import com.google.gerrit.reviewdb.server.ReviewDbUtil;
 import com.google.gerrit.server.config.AllUsersName;
 import com.google.gerrit.server.config.AllUsersNameProvider;
 import com.google.gerrit.server.git.GitRepositoryManager;
+import com.google.gerrit.server.git.ScanningChangeCacheImpl;
 import com.google.gerrit.server.project.NoSuchChangeException;
+import com.google.gerrit.server.project.ProjectCache;
 import com.google.gerrit.server.query.change.ChangeData;
 import com.google.gerrit.server.query.change.InternalChangeQuery;
 import com.google.gwtorm.server.OrmException;
@@ -57,6 +62,7 @@ import org.eclipse.jgit.errors.ConfigInvalidException;
 import org.eclipse.jgit.lib.CommitBuilder;
 import org.eclipse.jgit.lib.ObjectId;
 import org.eclipse.jgit.lib.PersonIdent;
+import org.eclipse.jgit.lib.Repository;
 import org.eclipse.jgit.notes.NoteMap;
 import org.eclipse.jgit.revwalk.RevWalk;
 import org.slf4j.Logger;
@@ -116,17 +122,20 @@ public class ChangeNotes extends AbstractChangeNotes<ChangeNotes> {
     private final NotesMigration migration;
     private final AllUsersNameProvider allUsersProvider;
     private final Provider<InternalChangeQuery> queryProvider;
+    private final ProjectCache projectCache;
 
     @VisibleForTesting
     @Inject
     public Factory(GitRepositoryManager repoManager,
         NotesMigration migration,
         AllUsersNameProvider allUsersProvider,
-        Provider<InternalChangeQuery> queryProvider) {
+        Provider<InternalChangeQuery> queryProvider,
+        ProjectCache projectCache) {
       this.repoManager = repoManager;
       this.migration = migration;
       this.allUsersProvider = allUsersProvider;
       this.queryProvider = queryProvider;
+      this.projectCache = projectCache;
     }
 
     public ChangeNotes createChecked(ReviewDb db, Change c)
@@ -190,6 +199,45 @@ public class ChangeNotes extends AbstractChangeNotes<ChangeNotes> {
       return new ChangeNotes(repoManager, migration, allUsersProvider,
           change.getProject(), change).load();
     }
+
+    // TODO(ekempin): Remove when database backend is deleted
+    /**
+     * Instantiate ChangeNotes for a change that has been loaded by a batch read
+     * from the database.
+     */
+    public ChangeNotes createFromChangeOnlyWhenNotedbDisabled(Change change)
+        throws OrmException {
+      checkState(!migration.readChanges(), "do not call"
+          + " createFromChangeWhenNotedbDisabled when notedb is enabled");
+      return new ChangeNotes(repoManager, migration, allUsersProvider,
+          change.getProject(), change).load();
+    }
+
+    public ListMultimap<Project.NameKey, ChangeNotes> create(ReviewDb db,
+        Predicate<ChangeNotes> predicate) throws IOException, OrmException {
+      ListMultimap<Project.NameKey, ChangeNotes> m = ArrayListMultimap.create();
+      if (migration.readChanges()) {
+        for (Project.NameKey project : projectCache.all()) {
+          try (Repository repo = repoManager.openRepository(project)) {
+            List<ChangeNotes> changes =
+                ScanningChangeCacheImpl.scanNotedb(this, repo, db, project);
+            for (ChangeNotes cn : changes) {
+              if (predicate.apply(cn)) {
+                m.put(project, cn);
+              }
+            }
+          }
+        }
+      } else {
+        for (Change change : db.changes().all()) {
+          ChangeNotes notes = createFromChangeOnlyWhenNotedbDisabled(change);
+          if (predicate.apply(notes)) {
+            m.put(change.getProject(), notes);
+          }
+        }
+      }
+      return ImmutableListMultimap.copyOf(m);
+    }
   }
 
   private final Project.NameKey project;

plugins/reviewnotes

@@ -1 +1 @@
-Subproject commit d383ad3b52ecd2bf0f082b5c03e8e4dfcc121350
+Subproject commit 47c74e2da9443e028d8d52d95791e0cd15add822