1 files changed, 149 insertions, 0 deletions
diff --git a/gerrit-server/src/main/java/com/google/gerrit/server/query/change/AndSource.java b/gerrit-server/src/main/java/com/google/gerrit/server/query/change/AndSource.java
new file mode 100644
index 0000000000..e74b390db8
--- /dev/null
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/query/change/AndSource.java
@@ -0,0 +1,149 @@
+// Copyright (C) 2010 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.query.change;
+
+import com.google.gerrit.server.query.AndPredicate;
+import com.google.gerrit.server.query.Predicate;
+import com.google.gwtorm.client.OrmException;
+import com.google.gwtorm.client.ResultSet;
+import com.google.gwtorm.client.impl.ListResultSet;
+
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.Comparator;
+import java.util.List;
+
+class AndSource extends AndPredicate<ChangeData> implements ChangeDataSource {
+  private static final Comparator<Predicate<ChangeData>> CMP =
+      new Comparator<Predicate<ChangeData>>() {
+        @Override
+        public int compare(Predicate<ChangeData> a, Predicate<ChangeData> b) {
+          int ai = a instanceof ChangeDataSource ? 0 : 1;
+          int bi = b instanceof ChangeDataSource ? 0 : 1;
+          int cmp = ai - bi;
+
+          if (cmp == 0 //
+              && a instanceof ChangeDataSource //
+              && b instanceof ChangeDataSource) {
+            ai = ((ChangeDataSource) a).hasChange() ? 0 : 1;
+            bi = ((ChangeDataSource) b).hasChange() ? 0 : 1;
+            cmp = ai - bi;
+          }
+
+          if (cmp == 0) {
+            cmp = a.getCost() - b.getCost();
+          }
+
+          if (cmp == 0 //
+              && a instanceof ChangeDataSource //
+              && b instanceof ChangeDataSource) {
+            ChangeDataSource as = (ChangeDataSource) a;
+            ChangeDataSource bs = (ChangeDataSource) b;
+            cmp = as.getCardinality() - bs.getCardinality();
+          }
+
+          return cmp;
+        }
+      };
+
+  private static List<Predicate<ChangeData>> sort(
+      Collection<? extends Predicate<ChangeData>> that) {
+    ArrayList<Predicate<ChangeData>> r =
+        new ArrayList<Predicate<ChangeData>>(that);
+    Collections.sort(r, CMP);
+    return r;
+  }
+
+  private int cardinality = -1;
+
+  AndSource(final Collection<? extends Predicate<ChangeData>> that) {
+    super(sort(that));
+  }
+
+  @Override
+  public boolean hasChange() {
+    ChangeDataSource source = source();
+    return source != null && source.hasChange();
+  }
+
+  @Override
+  public ResultSet<ChangeData> read() throws OrmException {
+    ChangeDataSource source = source();
+    if (source == null) {
+      throw new OrmException("No ChangeDataSource: " + this);
+    }
+
+    // TODO(spearce) This probably should be more lazy.
+    //
+    ArrayList<ChangeData> r = new ArrayList<ChangeData>();
+    ChangeData last = null;
+    boolean skipped = false;
+    for (ChangeData data : source.read()) {
+      if (match(data)) {
+        r.add(data);
+      } else {
+        skipped = true;
+      }
+      last = data;
+    }
+
+    if (skipped && last != null && source instanceof Paginated) {
+      // If we our source is a paginated source and we skipped at
+      // 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;
+      while (skipped && r.size() < p.limit()) {
+        ChangeData lastBeforeRestart = last;
+        skipped = false;
+        last = null;
+        for (ChangeData data : p.restart(lastBeforeRestart)) {
+          if (match(data)) {
+            r.add(data);
+          } else {
+            skipped = true;
+          }
+          last = data;
+        }
+      }
+    }
+
+    return new ListResultSet<ChangeData>(r);
+  }
+
+  private ChangeDataSource source() {
+    for (Predicate<ChangeData> p : getChildren()) {
+      if (p instanceof ChangeDataSource) {
+        return (ChangeDataSource) p;
+      }
+    }
+    return null;
+  }
+
+  @Override
+  public int getCardinality() {
+    if (cardinality < 0) {
+      cardinality = Integer.MAX_VALUE;
+      for (Predicate<ChangeData> p : getChildren()) {
+        if (p instanceof ChangeDataSource) {
+          int c = ((ChangeDataSource) p).getCardinality();
+          cardinality = Math.min(cardinality, c);
+        }
+      }
+    }
+    return cardinality;
+  }
+}