ReplicatedQueryAlloc.java

/*
 *      Copyright (C) 2012, 2016  higherfrequencytrading.com
 *      Copyright (C) 2016 Roman Leventov
 *
 *      This program is free software: you can redistribute it and/or modify
 *      it under the terms of the GNU Lesser General Public License as published by
 *      the Free Software Foundation, either version 3 of the License.
 *
 *      This program is distributed in the hope that it will be useful,
 *      but WITHOUT ANY WARRANTY; without even the implied warranty of
 *      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *      GNU Lesser General Public License for more details.
 *
 *      You should have received a copy of the GNU Lesser General Public License
 *      along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

package net.openhft.chronicle.map.impl.stage.replication;

import net.openhft.chronicle.hash.ReplicatedHashSegmentContext;
import net.openhft.chronicle.hash.impl.stage.entry.SegmentStages;
import net.openhft.chronicle.hash.impl.stage.query.QueryAlloc;
import net.openhft.chronicle.hash.replication.ReplicableEntry;
import net.openhft.chronicle.map.MapAbsentEntry;
import net.openhft.chronicle.map.MapSegmentContext;
import net.openhft.chronicle.map.ReplicatedChronicleMap;
import net.openhft.chronicle.map.impl.IterationContext;
import net.openhft.chronicle.map.impl.ReplicatedChronicleMapHolder;
import net.openhft.sg.StageRef;
import net.openhft.sg.Staged;

import java.util.function.Consumer;

import static net.openhft.chronicle.hash.replication.TimeProvider.currentTime;
import static net.openhft.chronicle.hash.replication.TimeProvider.systemTimeIntervalBetween;

@Staged
public class ReplicatedQueryAlloc extends QueryAlloc {

    @StageRef ReplicatedChronicleMapHolder<?, ?, ?> mh;
    @StageRef SegmentStages s;

    final CleanupAction cleanupAction = new CleanupAction();

    /**
     * Returns {@code true} if at least one old deleted entry was removed.
     * @param prevPos position to skip during cleanup (because cleaned up separately)
     */
    public boolean forcedOldDeletedEntriesCleanup(long prevPos) {
        ReplicatedChronicleMap<?, ?, ?> map = mh.m();
        if (!map.cleanupRemovedEntries)
            return false;
        try (MapSegmentContext<?, ?, ?> sc = map.segmentContext(s.segmentIndex)) {
            cleanupAction.removedCompletely = 0;
            cleanupAction.posToSkip = prevPos;
            cleanupAction.iterationContext = (IterationContext<?, ?, ?>) sc;
            ((ReplicatedHashSegmentContext<?, ?>) sc)
                    .forEachSegmentReplicableEntry(cleanupAction);
            return cleanupAction.removedCompletely > 0;
        }
    }

    private class CleanupAction implements Consumer<ReplicableEntry> {
        int removedCompletely;
        long posToSkip;
        IterationContext<?, ?, ?> iterationContext;

        @Override
        public void accept(ReplicableEntry e) {
            ReplicatedChronicleMap<?, ?, ?> map = mh.m();
            if (!(e instanceof MapAbsentEntry) || iterationContext.pos() == posToSkip)
                return;
            long currentTime = currentTime();
            if (e.originTimestamp() > currentTime)
                return; // presumably unsynchronized clocks
            long deleteTimeout = systemTimeIntervalBetween(
                    e.originTimestamp(), currentTime, map.cleanupTimeoutUnit);
            if (deleteTimeout <= map.cleanupTimeout || e.isChanged())
                return;
            e.doRemoveCompletely();
            removedCompletely++;
        }
    }

    @Override
    public long alloc(int chunks, long prevPos, int prevChunks) {
        long ret = s.allocReturnCode(chunks);
        if (ret >= 0) {
            if (prevPos >= 0)
                s.free(prevPos, prevChunks);
            return ret;
        }
        int firstAttemptedTier = s.tier;
        long firstAttemptedTierIndex = s.tierIndex;
        long firstAttemptedTierBaseAddr = s.tierBaseAddr;
        boolean cleanedFirstAttemptedTier = forcedOldDeletedEntriesCleanup(prevPos);
        s.goToFirstTier();
        while (true) {
            boolean visitingFirstAttemptedTier = s.tier == firstAttemptedTier;
            if (cleanedFirstAttemptedTier || !visitingFirstAttemptedTier) {
                ret = s.allocReturnCode(chunks);
                if (ret >= 0) {
                    if (prevPos >= 0) {
                        if (visitingFirstAttemptedTier) {
                            s.free(prevPos, prevChunks);
                        } else if (s.tier < firstAttemptedTier) {
                            int currentTier = s.tier;
                            long currentTierIndex = s.tierIndex;
                            long currentTierBaseAddr = s.tierBaseAddr;
                            s.initSegmentTier(firstAttemptedTier, firstAttemptedTierIndex,
                                    firstAttemptedTierBaseAddr);
                            s.free(prevPos, prevChunks);
                            s.initSegmentTier(currentTier, currentTierIndex, currentTierBaseAddr);
                        }
                    }
                    return ret;
                }
            }
            if (visitingFirstAttemptedTier && prevPos >= 0)
                s.free(prevPos, prevChunks);
            s.nextTier();
        }
    }
}