Add IndexedAccountQuery

This change extracts the generic parts from IndexedChangeQuery into a
base class that can also be used as base for IndexedAccountQuery.

IndexedAccountQuery will be needed to implement AccountIndexRewriter.

Change-Id: I865868a866ca3cda84ef28bad0733b41f776dff4
Signed-off-by: Edwin Kempin <ekempin@google.com>

gerrit-server/src/main/java/com/google/gerrit/server/index/IndexedQuery.java

@@ -0,0 +1,183 @@
+// Copyright (C) 2016 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.gerrit.server.index;
+
+import com.google.common.base.Function;
+import com.google.common.base.MoreObjects;
+import com.google.common.collect.ImmutableList;
+import com.google.common.collect.Iterables;
+import com.google.gerrit.server.query.DataSource;
+import com.google.gerrit.server.query.Paginated;
+import com.google.gerrit.server.query.Predicate;
+import com.google.gerrit.server.query.QueryParseException;
+import com.google.gwtorm.server.OrmException;
+import com.google.gwtorm.server.ResultSet;
+
+import java.util.Collection;
+import java.util.HashMap;
+import java.util.Iterator;
+import java.util.List;
+import java.util.Map;
+
+/**
+ * Wrapper combining an {@link IndexPredicate} together with a
+ * {@link DataSource} that returns matching results from the index.
+ * <p>
+ * Appropriate to return as the rootmost predicate that can be processed using
+ * the secondary index; such predicates must also implement {@link DataSource}
+ * to be chosen by the query processor.
+ *
+ * @param <I> The type of the IDs by which the entities are stored in the index.
+ * @param <T> The type of the entities that are stored in the index.
+ */
+public class IndexedQuery<I, T> extends Predicate<T>
+    implements DataSource<T>, Paginated<T> {
+  protected final Index<I, T> index;
+
+  private QueryOptions opts;
+  private final Predicate<T> pred;
+  private DataSource<T> source;
+  private final Map<T, DataSource<T>> fromSource;
+
+  public IndexedQuery(Index<I, T> index, Predicate<T> pred,
+      QueryOptions opts) throws QueryParseException {
+    this.index = index;
+    this.opts = opts;
+    this.pred = pred;
+    this.source = index.getSource(pred, this.opts);
+    this.fromSource = new HashMap<>();
+  }
+
+  @Override
+  public int getChildCount() {
+    return 1;
+  }
+
+  @Override
+  public Predicate<T> getChild(int i) {
+    if (i == 0) {
+      return pred;
+    }
+    throw new ArrayIndexOutOfBoundsException(i);
+  }
+
+  @Override
+  public List<Predicate<T>> getChildren() {
+    return ImmutableList.of(pred);
+  }
+
+  @Override
+  public QueryOptions getOptions() {
+    return opts;
+  }
+
+  @Override
+  public int getCardinality() {
+    return source != null ? source.getCardinality() : opts.limit();
+  }
+
+  @Override
+  public ResultSet<T> read() throws OrmException {
+    final DataSource<T> currSource = source;
+    final ResultSet<T> rs = currSource.read();
+
+    return new ResultSet<T>() {
+      @Override
+      public Iterator<T> iterator() {
+        return Iterables.transform(
+            rs,
+            new Function<T, T>() {
+              @Override
+              public
+              T apply(T t) {
+                fromSource.put(t, currSource);
+                return t;
+              }
+            }).iterator();
+      }
+
+      @Override
+      public List<T> toList() {
+        List<T> r = rs.toList();
+        for (T t : r) {
+          fromSource.put(t, currSource);
+        }
+        return r;
+      }
+
+      @Override
+      public void close() {
+        rs.close();
+      }
+    };
+  }
+
+  @Override
+  public ResultSet<T> restart(int start) throws OrmException {
+    opts = opts.withStart(start);
+    try {
+      source = index.getSource(pred, opts);
+    } catch (QueryParseException e) {
+      // Don't need to show this exception to the user; the only thing that
+      // changed about pred was its start, and any other QPEs that might happen
+      // should have already thrown from the constructor.
+      throw new OrmException(e);
+    }
+    // Don't convert start to a limit, since the caller of this method (see
+    // AndSource) has calculated the actual number to skip.
+    return read();
+  }
+
+  @Override
+  public Predicate<T> copy(Collection<? extends Predicate<T>> children) {
+    return this;
+  }
+
+  @Override
+  public boolean match(T t) throws OrmException {
+    return (source != null && fromSource.get(t) == source) || pred.match(t);
+  }
+
+  @Override
+  public int getCost() {
+    // Index queries are assumed to be cheaper than any other type of query, so
+    // so try to make sure they get picked. Note that pred's cost may be higher
+    // because it doesn't know whether it's being used in an index query or not.
+    return 1;
+  }
+
+  @Override
+  public int hashCode() {
+    return pred.hashCode();
+  }
+
+  @Override
+  public boolean equals(Object other) {
+    if (other == null || getClass() != other.getClass()) {
+      return false;
+    }
+    IndexedQuery<?, ?> o = (IndexedQuery<?, ?>) other;
+    return pred.equals(o.pred)
+        && opts.equals(o.opts);
+  }
+
+  @Override
+  public String toString() {
+    return MoreObjects.toStringHelper("index")
+        .add("p", pred)
+        .add("opts", opts)
+        .toString();
+  }
+}

gerrit-server/src/main/java/com/google/gerrit/server/index/account/IndexedAccountQuery.java

@@ -0,0 +1,34 @@
+// Copyright (C) 2016 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.gerrit.server.index.account;
+
+import com.google.gerrit.reviewdb.client.Account;
+import com.google.gerrit.server.account.AccountState;
+import com.google.gerrit.server.index.Index;
+import com.google.gerrit.server.index.IndexedQuery;
+import com.google.gerrit.server.index.QueryOptions;
+import com.google.gerrit.server.query.DataSource;
+import com.google.gerrit.server.query.Predicate;
+import com.google.gerrit.server.query.QueryParseException;
+
+public class IndexedAccountQuery extends IndexedQuery<Account.Id, AccountState>
+    implements DataSource<AccountState> {
+
+  public IndexedAccountQuery(Index<Account.Id, AccountState> index,
+      Predicate<AccountState> pred, QueryOptions opts)
+          throws QueryParseException {
+    super(index, pred, opts);
+  }
+}

gerrit-server/src/main/java/com/google/gerrit/server/index/change/IndexedChangeQuery.java

@@ -18,28 +18,19 @@ import static com.google.gerrit.server.index.change.ChangeField.CHANGE;
 import static com.google.gerrit.server.index.change.ChangeField.PROJECT;
 
 import com.google.common.annotations.VisibleForTesting;
-import com.google.common.base.Function;
-import com.google.common.base.MoreObjects;
-import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableSet;
-import com.google.common.collect.Iterables;
 import com.google.common.primitives.Ints;
+import com.google.gerrit.reviewdb.client.Change;
 import com.google.gerrit.server.index.IndexConfig;
 import com.google.gerrit.server.index.IndexPredicate;
+import com.google.gerrit.server.index.IndexedQuery;
 import com.google.gerrit.server.index.QueryOptions;
-import com.google.gerrit.server.query.DataSource;
 import com.google.gerrit.server.query.Predicate;
 import com.google.gerrit.server.query.QueryParseException;
 import com.google.gerrit.server.query.change.ChangeData;
 import com.google.gerrit.server.query.change.ChangeDataSource;
-import com.google.gerrit.server.query.change.Paginated;
-import com.google.gwtorm.server.OrmException;
-import com.google.gwtorm.server.ResultSet;
 
-import java.util.Collection;
 import java.util.HashSet;
-import java.util.Iterator;
-import java.util.List;
 import java.util.Set;
 
 /**
@@ -50,8 +41,8 @@ import java.util.Set;
  * the secondary index; such predicates must also implement
  * {@link ChangeDataSource} to be chosen by the query processor.
  */
-public class IndexedChangeQuery extends Predicate<ChangeData>
-    implements ChangeDataSource, Paginated {
+public class IndexedChangeQuery extends IndexedQuery<Change.Id, ChangeData>
+    implements ChangeDataSource {
   public static QueryOptions oneResult() {
     return createOptions(IndexConfig.createDefault(), 0, 1,
         ImmutableSet.<String> of());
@@ -78,144 +69,13 @@ public class IndexedChangeQuery extends Predicate<ChangeData>
     return IndexedChangeQuery.createOptions(opts.config(), 0, limit, opts.fields());
   }
 
-  private final ChangeIndex index;
-
-  private QueryOptions opts;
-  private Predicate<ChangeData> pred;
-  private DataSource<ChangeData> source;
-
   public IndexedChangeQuery(ChangeIndex index, Predicate<ChangeData> pred,
       QueryOptions opts) throws QueryParseException {
-    this.index = index;
-    this.opts = convertOptions(opts);
-    this.pred = pred;
-    this.source = index.getSource(pred, this.opts);
-  }
-
-  @Override
-  public int getChildCount() {
-    return 1;
-  }
-
-  @Override
-  public Predicate<ChangeData> getChild(int i) {
-    if (i == 0) {
-      return pred;
-    }
-    throw new ArrayIndexOutOfBoundsException(i);
-  }
-
-  @Override
-  public List<Predicate<ChangeData>> getChildren() {
-    return ImmutableList.of(pred);
-  }
-
-  @Override
-  public QueryOptions getOptions() {
-    return opts;
-  }
-
-  @Override
-  public int getCardinality() {
-    return source != null ? source.getCardinality() : opts.limit();
+    super(index, pred, convertOptions(opts));
   }
 
   @Override
   public boolean hasChange() {
     return index.getSchema().hasField(ChangeField.CHANGE);
   }
-
-  @Override
-  public ResultSet<ChangeData> read() throws OrmException {
-    final DataSource<ChangeData> currSource = source;
-    final ResultSet<ChangeData> rs = currSource.read();
-
-    return new ResultSet<ChangeData>() {
-      @Override
-      public Iterator<ChangeData> iterator() {
-        return Iterables.transform(
-            rs,
-            new Function<ChangeData, ChangeData>() {
-              @Override
-              public
-              ChangeData apply(ChangeData input) {
-                input.cacheFromSource(currSource);
-                return input;
-              }
-            }).iterator();
-      }
-
-      @Override
-      public List<ChangeData> toList() {
-        List<ChangeData> r = rs.toList();
-        for (ChangeData cd : r) {
-          cd.cacheFromSource(currSource);
-        }
-        return r;
-      }
-
-      @Override
-      public void close() {
-        rs.close();
-      }
-    };
-  }
-
-  @Override
-  public ResultSet<ChangeData> restart(int start) throws OrmException {
-    opts = opts.withStart(start);
-    try {
-      source = index.getSource(pred, opts);
-    } catch (QueryParseException e) {
-      // Don't need to show this exception to the user; the only thing that
-      // changed about pred was its start, and any other QPEs that might happen
-      // should have already thrown from the constructor.
-      throw new OrmException(e);
-    }
-    // Don't convert start to a limit, since the caller of this method (see
-    // AndSource) has calculated the actual number to skip.
-    return read();
-  }
-
-  @Override
-  public Predicate<ChangeData> copy(
-      Collection<? extends Predicate<ChangeData>> children) {
-    return this;
-  }
-
-  @Override
-  public boolean match(ChangeData cd) throws OrmException {
-    return (source != null && cd.isFromSource(source)) || pred.match(cd);
-  }
-
-  @Override
-  public int getCost() {
-    // Index queries are assumed to be cheaper than any other type of query, so
-    // so try to make sure they get picked. Note that pred's cost may be higher
-    // because it doesn't know whether it's being used in an index query or not.
-    return 1;
-  }
-
-  @Override
-  public int hashCode() {
-    return pred.hashCode();
-  }
-
-  @Override
-  public boolean equals(Object other) {
-    if (other == null || getClass() != other.getClass()) {
-      return false;
-    }
-    IndexedChangeQuery o = (IndexedChangeQuery) other;
-    return pred.equals(o.pred)
-        && opts.equals(o.opts);
-  }
-
-  @Override
-  public String toString() {
-    return MoreObjects.toStringHelper("index")
-        .add("p", pred)
-        .add("opts", opts)
-        .toString();
-  }
 }

gerrit-server/src/main/java/com/google/gerrit/server/query/Paginated.java

@@ -12,14 +12,14 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package com.google.gerrit.server.query.change;
+package com.google.gerrit.server.query;
 
 import com.google.gerrit.server.index.QueryOptions;
 import com.google.gwtorm.server.OrmException;
 import com.google.gwtorm.server.ResultSet;
 
-public interface Paginated {
+public interface Paginated<T> {
   QueryOptions getOptions();
 
-  ResultSet<ChangeData> restart(int start) throws OrmException;
+  ResultSet<T> restart(int start) throws OrmException;
 }

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

@@ -22,6 +22,7 @@ import com.google.common.collect.FluentIterable;
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.Iterables;
 import com.google.gerrit.server.query.AndPredicate;
+import com.google.gerrit.server.query.Paginated;
 import com.google.gerrit.server.query.Predicate;
 import com.google.gwtorm.server.ListResultSet;
 import com.google.gwtorm.server.OrmException;
@@ -126,7 +127,8 @@ public class AndSource extends AndPredicate<ChangeData>
       // least one of its results, we may not have filled the full
       // limit the caller wants.  Restart the source and continue.
       //
-      Paginated p = (Paginated) source;
+      @SuppressWarnings("unchecked")
+      Paginated<ChangeData> p = (Paginated<ChangeData>) source;
       while (skipped && r.size() < p.getOptions().limit() + start) {
         skipped = false;
         ResultSet<ChangeData> next = p.restart(nextStart);

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

@@ -64,7 +64,6 @@ import com.google.gerrit.server.project.ChangeControl;
 import com.google.gerrit.server.project.NoSuchChangeException;
 import com.google.gerrit.server.project.ProjectCache;
 import com.google.gerrit.server.project.SubmitRuleEvaluator;
-import com.google.gerrit.server.query.DataSource;
 import com.google.gwtorm.server.OrmException;
 import com.google.gwtorm.server.ResultSet;
 import com.google.inject.assistedinject.Assisted;
@@ -323,7 +322,6 @@ public class ChangeData {
   private final MergeabilityCache mergeabilityCache;
   private final StarredChangesUtil starredChangesUtil;
   private final Change.Id legacyId;
-  private DataSource<ChangeData> returnedBySource;
   private Project.NameKey project;
   private Change change;
   private ChangeNotes notes;
@@ -551,14 +549,6 @@ public class ChangeData {
     return db;
   }
 
-  public boolean isFromSource(DataSource<ChangeData> s) {
-    return s == returnedBySource;
-  }
-
-  public void cacheFromSource(DataSource<ChangeData> s) {
-    returnedBySource = s;
-  }
-
   public void setCurrentFilePaths(List<String> filePaths) throws OrmException {
     PatchSet ps = currentPatchSet();
     if (ps != null) {