blob: 35b42a33588a985d11744e89547b97ae9fcb25bf [file] [log] [blame]
// Copyright 2014 The Bazel Authors. All rights reserved.
//
// 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.devtools.build.skyframe;
import com.google.common.base.Function;
import com.google.common.collect.Maps;
import java.util.Collection;
import java.util.Map;
import javax.annotation.Nullable;
/**
* Calculate set of changed values in a graph.
*/
public interface Differencer {
/**
* Represents a set of changed values.
*/
interface Diff {
default boolean isEmpty() {
return changedKeysWithoutNewValues().isEmpty() && changedKeysWithNewValues().isEmpty();
}
/**
* Returns the value keys whose values have changed, but for which we don't have the new values.
*/
Collection<SkyKey> changedKeysWithoutNewValues();
/**
* Returns the value keys whose values have changed, along with their new values.
*
* <p> The values in here cannot have any dependencies. This is required in order to prevent
* conflation of injected values and derived values.
*/
Map<SkyKey, SkyValue> changedKeysWithNewValues();
}
/** A {@Diff} that also potentially contains the new and old values for each changed key. */
interface DiffWithDelta extends Diff {
/** Returns the value keys whose values have changed, along with their old and new values. */
Map<SkyKey, Delta> changedKeysWithNewAndOldValues();
/** Represents the delta between two values of the same key. */
final class Delta {
private static final Function<Delta, SkyValue> NEW_VALUE_EXTRACTOR =
new Function<Delta, SkyValue>() {
@Override
public SkyValue apply(Delta delta) {
return delta.getNewValue();
}
};
@Nullable
private final SkyValue oldValue;
private final SkyValue newValue;
public Delta(SkyValue newValue) {
this(null, newValue);
}
public Delta(SkyValue oldValue, SkyValue newValue) {
this.oldValue = oldValue;
this.newValue = newValue;
}
/** Returns the old value, if any. */
@Nullable
public SkyValue getOldValue() {
return oldValue;
}
/** Returns the new value. */
public SkyValue getNewValue() {
return newValue;
}
public static Map<SkyKey, SkyValue> newValues(Map<SkyKey, Delta> delta) {
return Maps.transformValues(delta, NEW_VALUE_EXTRACTOR);
}
}
}
/**
* Returns the value keys that have changed between the two Versions.
*/
Diff getDiff(WalkableGraph fromGraph, Version fromVersion, Version toVersion)
throws InterruptedException;
}