com.google.devtools.build.skyframe.InMemoryGraph.java Source code

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Here is the source code for com.google.devtools.build.skyframe.InMemoryGraph.java

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// Copyright 2014 Google Inc. 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.annotations.VisibleForTesting;
import com.google.common.base.Function;
import com.google.common.base.Predicate;
import com.google.common.base.Predicates;
import com.google.common.collect.ImmutableMap;
import com.google.common.collect.MapMaker;
import com.google.common.collect.Maps;

import java.util.Collections;
import java.util.Map;
import java.util.concurrent.ConcurrentMap;

import javax.annotation.Nullable;

/**
 * An in-memory graph implementation. All operations are thread-safe with ConcurrentMap semantics.
 * Also see {@link NodeEntry}.
 *
 * <p>This class is public only for use in alternative graph implementations.
 */
public class InMemoryGraph implements ProcessableGraph {

    protected final ConcurrentMap<SkyKey, NodeEntry> nodeMap = new MapMaker().initialCapacity(1024)
            .concurrencyLevel(200).makeMap();
    private final boolean keepEdges;

    InMemoryGraph() {
        this(/*keepEdges=*/true);
    }

    public InMemoryGraph(boolean keepEdges) {
        this.keepEdges = keepEdges;
    }

    @Override
    public void remove(SkyKey skyKey) {
        nodeMap.remove(skyKey);
    }

    @Override
    public NodeEntry get(SkyKey skyKey) {
        return nodeMap.get(skyKey);
    }

    @Override
    public Map<SkyKey, NodeEntry> getBatch(Iterable<SkyKey> keys) {
        ImmutableMap.Builder<SkyKey, NodeEntry> builder = ImmutableMap.builder();
        for (SkyKey key : keys) {
            NodeEntry entry = get(key);
            if (entry != null) {
                builder.put(key, entry);
            }
        }
        return builder.build();
    }

    @Override
    public NodeEntry createIfAbsent(SkyKey key) {
        NodeEntry newval = keepEdges ? new InMemoryNodeEntry() : new EdgelessInMemoryNodeEntry();
        NodeEntry oldval = nodeMap.putIfAbsent(key, newval);
        return oldval == null ? newval : oldval;
    }

    /** Only done nodes exist to the outside world. */
    private static final Predicate<NodeEntry> NODE_DONE_PREDICATE = new Predicate<NodeEntry>() {
        @Override
        public boolean apply(NodeEntry entry) {
            return entry != null && entry.isDone();
        }
    };

    /**
     * Returns a value, if it exists. If not, returns null.
     */
    @Nullable
    public SkyValue getValue(SkyKey key) {
        NodeEntry entry = get(key);
        return NODE_DONE_PREDICATE.apply(entry) ? entry.getValue() : null;
    }

    /**
     * Returns a read-only live view of the nodes in the graph. All node are included. Dirty values
     * include their Node value. Values in error have a null value.
     */
    Map<SkyKey, SkyValue> getValues() {
        return Collections.unmodifiableMap(Maps.transformValues(nodeMap, new Function<NodeEntry, SkyValue>() {
            @Override
            public SkyValue apply(NodeEntry entry) {
                return entry.toValue();
            }
        }));
    }

    /**
     * Returns a read-only live view of the done values in the graph. Dirty, changed, and error values
     * are not present in the returned map
     */
    Map<SkyKey, SkyValue> getDoneValues() {
        return Collections.unmodifiableMap(
                Maps.filterValues(Maps.transformValues(nodeMap, new Function<NodeEntry, SkyValue>() {
                    @Override
                    public SkyValue apply(NodeEntry entry) {
                        return entry.isDone() ? entry.getValue() : null;
                    }
                }), Predicates.notNull()));
    }

    // Only for use by MemoizingEvaluator#delete
    Map<SkyKey, NodeEntry> getAllValues() {
        return Collections.unmodifiableMap(nodeMap);
    }

    @VisibleForTesting
    protected ConcurrentMap<SkyKey, NodeEntry> getNodeMap() {
        return nodeMap;
    }

    boolean keepsEdges() {
        return keepEdges;
    }
}