com.google.gitiles.TimeCache.java Source code

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Here is the source code for com.google.gitiles.TimeCache.java

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// Copyright 2012 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.gitiles;

import com.google.common.base.Throwables;
import com.google.common.cache.Cache;
import com.google.common.cache.CacheBuilder;

import org.eclipse.jgit.lib.Constants;
import org.eclipse.jgit.lib.ObjectId;
import org.eclipse.jgit.lib.PersonIdent;
import org.eclipse.jgit.revwalk.RevCommit;
import org.eclipse.jgit.revwalk.RevObject;
import org.eclipse.jgit.revwalk.RevTag;
import org.eclipse.jgit.revwalk.RevWalk;

import java.io.IOException;
import java.util.concurrent.Callable;
import java.util.concurrent.ExecutionException;

/**
 * Cache of the time associated with Git objects.
 * <p>
 * Uses the time as stored in annotated tags if available, or else the commit
 * time of the tagged commit. Non-commits are given {@link Long#MIN_VALUE},
 * rather than searching for occurrences in the entire repository.
 */
public class TimeCache {
    public static CacheBuilder<Object, Object> defaultBuilder() {
        return CacheBuilder.newBuilder().maximumSize(10 << 10);
    }

    private final Cache<ObjectId, Long> cache;

    public TimeCache() {
        this(defaultBuilder());
    }

    public TimeCache(CacheBuilder<Object, Object> builder) {
        this.cache = builder.build();
    }

    public Cache<?, ?> getCache() {
        return cache;
    }

    Long getTime(final RevWalk walk, final ObjectId id) throws IOException {
        try {
            return cache.get(id, new Callable<Long>() {
                @Override
                public Long call() throws IOException {
                    RevObject o = walk.parseAny(id);
                    while (o instanceof RevTag) {
                        RevTag tag = (RevTag) o;
                        PersonIdent ident = tag.getTaggerIdent();
                        if (ident != null) {
                            return ident.getWhen().getTime() / 1000;
                        }
                        o = tag.getObject();
                        walk.parseHeaders(o);
                    }
                    if (o.getType() == Constants.OBJ_COMMIT) {
                        return Long.valueOf(((RevCommit) o).getCommitTime());
                    }
                    return Long.MIN_VALUE;
                }
            });
        } catch (ExecutionException e) {
            Throwables.propagateIfInstanceOf(e.getCause(), IOException.class);
            throw new IOException(e);
        }
    }
}