Package org.tmatesoft.hg.internal

Source Code of org.tmatesoft.hg.internal.RevlogStreamWriter

/*
* Copyright (c) 2013 TMate Software Ltd
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; version 2 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 General Public License for more details.
*
* For information on how to redistribute this software under
* the terms of a license other than GNU General Public License
* contact TMate Software at support@hg4j.com
*/
package org.tmatesoft.hg.internal;

import static org.tmatesoft.hg.internal.Internals.REVLOGV1_RECORD_SIZE;
import static org.tmatesoft.hg.repo.HgRepository.BAD_REVISION;
import static org.tmatesoft.hg.repo.HgRepository.NO_REVISION;

import java.io.IOException;
import java.nio.ByteBuffer;

import org.tmatesoft.hg.core.HgIOException;
import org.tmatesoft.hg.core.Nodeid;
import org.tmatesoft.hg.core.SessionContext;
import org.tmatesoft.hg.internal.DataSerializer.ByteArrayDataSource;
import org.tmatesoft.hg.internal.DataSerializer.ByteArraySerializer;
import org.tmatesoft.hg.internal.DataSerializer.DataSource;
import org.tmatesoft.hg.repo.HgBundle.GroupElement;
import org.tmatesoft.hg.repo.HgInternals;
import org.tmatesoft.hg.repo.HgInvalidControlFileException;
import org.tmatesoft.hg.repo.HgInvalidDataFormatException;
import org.tmatesoft.hg.repo.HgInvalidRevisionException;
import org.tmatesoft.hg.repo.HgInvalidStateException;
import org.tmatesoft.hg.repo.HgRepository;
import org.tmatesoft.hg.repo.HgRuntimeException;
import org.tmatesoft.hg.util.Pair;

/**
*
* TODO [post-1.1] separate operation to check if index is too big and split into index+data
*
* @author Artem Tikhomirov
* @author TMate Software Ltd.
*/
public class RevlogStreamWriter {

  private final DigestHelper dh = new DigestHelper();
  private final RevlogCompressor revlogDataZip;
  private final Transaction transaction;
  // init with illegal values
  private int lastEntryBase = BAD_REVISION, lastEntryIndex = BAD_REVISION, lastEntryActualLen = -1;
  // record revision and its full content
  // the name might be misleading, it does not necessarily match lastEntryIndex
  private Pair<Integer, byte[]> lastFullContent;
  private Nodeid lastEntryRevision;
  private IntMap<Nodeid> revisionCache = new IntMap<Nodeid>(32);
  private RevlogStream revlogStream;
 
  public RevlogStreamWriter(SessionContext.Source ctxSource, RevlogStream stream, Transaction tr) {
    assert ctxSource != null;
    assert stream != null;
    assert tr != null;
       
    revlogDataZip = new RevlogCompressor(ctxSource.getSessionContext());
    revlogStream = stream;
    transaction = tr;
  }
 
  public RevlogStream getRevlogStream() {
    return revlogStream;
  }
 
  public Pair<Integer,Nodeid> addPatchRevision(GroupElement ge, RevisionToIndexMap clogRevs, RevisionToIndexMap revlogRevs) throws HgIOException, HgRuntimeException {
    populateLastEntryIndex();
    //
    final Nodeid nodeRev = ge.node();
    final Nodeid csetRev = ge.cset();
    int linkRev;
    if (nodeRev.equals(csetRev)) {
      linkRev = lastEntryIndex+1;
    } else {
      linkRev = clogRevs.revisionIndex(csetRev);
    }
    assert linkRev >= 0;
    final Nodeid p1Rev = ge.firstParent();
    int p1 = p1Rev.isNull() ? NO_REVISION : revlogRevs.revisionIndex(p1Rev);
    final Nodeid p2Rev = ge.secondParent();
    int p2 = p2Rev.isNull() ? NO_REVISION : revlogRevs.revisionIndex(p2Rev);
    Patch p = null;
    try {
      p = HgInternals.patchFromData(ge);
    } catch (IOException ex) {
      throw new HgIOException("Failed to read patch information", ex, null);
    }
    //
    final Nodeid patchBase = ge.patchBase();
    int patchBaseRev = patchBase.isNull() ? NO_REVISION : revlogRevs.revisionIndex(patchBase);
    int baseRev = lastEntryIndex == NO_REVISION ? 0 : revlogStream.baseRevision(patchBaseRev);
    int revLen;
    DataSource ds;
    byte[] complete = null;
    if (patchBaseRev == lastEntryIndex && lastEntryIndex != NO_REVISION) {
      // we may write patch from GroupElement as is
      int patchBaseLen = dataLength(patchBaseRev);
      revLen = patchBaseLen + p.patchSizeDelta();
      ds = p.new PatchDataSource();
    } else {
      // read baseRev, unless it's the pull to empty repository
      try {
        if (lastEntryIndex == NO_REVISION) {
          complete = p.apply(new ByteArrayDataAccess(new byte[0]), -1);
          baseRev = 0; // it's done above, but doesn't hurt
        } else {
          assert patchBaseRev != NO_REVISION;
          ReadContentInspector insp = new ReadContentInspector().read(revlogStream, patchBaseRev);
          complete = p.apply(new ByteArrayDataAccess(insp.content), -1);
          baseRev = lastEntryIndex + 1;
        }
        ds = new ByteArrayDataSource(complete);
        revLen = complete.length;
      } catch (IOException ex) {
        // unlikely to happen, as ByteArrayDataSource throws IOException only in case of programming errors
        // hence, throwing rt exception here makes more sense here than HgIOException (even that latter is in throws)
        throw new HgInvalidDataFormatException("Failed to reconstruct revision", ex);
      }
    }
    doAdd(nodeRev, p1, p2, linkRev, baseRev, revLen, ds);
    if (complete != null) {
      lastFullContent = new Pair<Integer, byte[]>(lastEntryIndex, complete);
    }
    return new Pair<Integer, Nodeid>(lastEntryIndex, lastEntryRevision);
  }
 
  /**
   * @return nodeid of added revision
   * @throws HgRuntimeException
   */
  public Pair<Integer,Nodeid> addRevision(DataSource content, int linkRevision, int p1, int p2) throws HgIOException, HgRuntimeException {
    populateLastEntryIndex();
    populateLastEntryContent();
    //
    byte[] contentByteArray = toByteArray(content);
    Nodeid p1Rev = revision(p1);
    Nodeid p2Rev = revision(p2);
    Nodeid newRev = Nodeid.fromBinary(dh.sha1(p1Rev, p2Rev, contentByteArray).asBinary(), 0);
    if (newRev.equals(p1Rev)) { // shall never happen, same content but different parents give new SHA. Doesn't hurt to check, though
      assert p2Rev.isNull();
      return new Pair<Integer, Nodeid>(p1, p1Rev);
    }
    //
    Patch patch = GeneratePatchInspector.delta(lastFullContent.second(), contentByteArray);
    int patchSerializedLength = patch.serializedLength();
    final boolean writeComplete = preferCompleteOverPatch(patchSerializedLength, contentByteArray.length);
    DataSerializer.DataSource dataSource = writeComplete ? new ByteArrayDataSource(contentByteArray) : patch.new PatchDataSource();
    //
    doAdd(newRev, p1, p2, linkRevision, writeComplete ? lastEntryIndex+1 : lastEntryBase, contentByteArray.length, dataSource);
    lastFullContent = new Pair<Integer, byte[]>(lastEntryIndex, contentByteArray);
    return new Pair<Integer, Nodeid>(lastEntryIndex, lastEntryRevision);
  }

  private Nodeid doAdd(Nodeid rev, int p1, int p2, int linkRevision, int baseRevision, int revLen, DataSerializer.DataSource dataSource) throws HgIOException, HgRuntimeException  {
    assert linkRevision >= 0;
    assert baseRevision >= 0;
    assert p1 == NO_REVISION || p1 >= 0;
    assert p2 == NO_REVISION || p2 >= 0;
    assert !rev.isNull();
    assert revLen >= 0;
    revlogDataZip.reset(dataSource);
    final int compressedLen;
    final boolean useCompressedData = preferCompressedOverComplete(revlogDataZip.getCompressedLength(), dataSource.serializeLength());
    if (useCompressedData) {
      compressedLen= revlogDataZip.getCompressedLength();
    } else {
      // compression wasn't too effective,
      compressedLen = dataSource.serializeLength() + 1 /*1 byte for 'u' - uncompressed prefix byte*/;
    }
    //
    DataSerializer indexFile, dataFile;
    indexFile = dataFile = null;
    try {
      // FIXME perhaps, not a good idea to open stream for each revision added (e.g, when we pull a lot of them)
      indexFile = revlogStream.getIndexStreamWriter(transaction);
      final boolean isInlineData = revlogStream.isInlineData();
      HeaderWriter revlogHeader = new HeaderWriter(isInlineData);
      revlogHeader.length(revLen, compressedLen);
      revlogHeader.nodeid(rev.toByteArray());
      revlogHeader.linkRevision(linkRevision);
      revlogHeader.parents(p1, p2);
      revlogHeader.baseRevision(baseRevision);
      long lastEntryOffset = revlogStream.newEntryOffset();
      revlogHeader.offset(lastEntryOffset);
      //
      revlogHeader.serialize(indexFile);
     
      if (isInlineData) {
        dataFile = indexFile;
      } else {
        dataFile = revlogStream.getDataStreamWriter(transaction);
      }
      if (useCompressedData) {
        int actualCompressedLenWritten = revlogDataZip.writeCompressedData(dataFile);
        if (actualCompressedLenWritten != compressedLen) {
          throw new HgInvalidStateException(String.format("Expected %d bytes of compressed data, but actually wrote %d in %s", compressedLen, actualCompressedLenWritten, revlogStream.getDataFileName()));
        }
      } else {
        dataFile.writeByte((byte) 'u');
        dataSource.serialize(dataFile);
      }
     
      lastEntryBase = revlogHeader.baseRevision();
      lastEntryIndex++;
      lastEntryActualLen = revLen;
      lastEntryRevision = rev;
      revisionCache.put(lastEntryIndex, lastEntryRevision);

      revlogStream.revisionAdded(lastEntryIndex, lastEntryRevision, lastEntryBase, lastEntryOffset);
    } finally {
      indexFile.done();
      if (dataFile != null && dataFile != indexFile) {
        dataFile.done();
      }
    }
    return lastEntryRevision;
  }
 
  private byte[] toByteArray(DataSource content) throws HgIOException, HgRuntimeException {
    ByteArraySerializer ba = new ByteArraySerializer();
    content.serialize(ba);
    return ba.toByteArray();
  }

  private Nodeid revision(int revisionIndex) throws HgInvalidControlFileException, HgInvalidRevisionException {
    if (revisionIndex == NO_REVISION) {
      return Nodeid.NULL;
    }
    Nodeid n = revisionCache.get(revisionIndex);
    if (n == null) {
      n = Nodeid.fromBinary(revlogStream.nodeid(revisionIndex), 0);
      revisionCache.put(revisionIndex, n);
    }
    return n;
  }
 
  private int dataLength(int revisionIndex) throws HgInvalidControlFileException, HgInvalidRevisionException {
    assert revisionIndex >= 0;
    if (revisionIndex == lastEntryIndex && lastEntryActualLen >= 0) {
      // if the last entry is the one we've just written, we know its actual len.
      // it's possible, however, that revisionIndex == lastEntryIndex just
      // because revision being added comes right after last locally known one
      // and lastEntryActualLen is not set
      return lastEntryActualLen;
    }
    if (lastFullContent != null && lastFullContent.first() == revisionIndex) {
      return lastFullContent.second().length;
    }
    return revlogStream.dataLength(revisionIndex);
  }
 
  private void populateLastEntryIndex() throws HgRuntimeException {
    int revCount = revlogStream.revisionCount();
    lastEntryIndex = revCount == 0 ? NO_REVISION : revCount - 1;
  }
 
  private void populateLastEntryContent() throws HgIOException, HgRuntimeException {
    if (lastFullContent != null && lastFullContent.first() == lastEntryIndex) {
      // we have last entry cached
      return;
    }
    lastEntryRevision = Nodeid.NULL;
    if (lastEntryIndex != NO_REVISION) {
      ReadContentInspector insp = new ReadContentInspector().read(revlogStream, lastEntryIndex);
      lastEntryBase = insp.baseRev;
      lastEntryRevision = insp.rev;
      lastFullContent = new Pair<Integer, byte[]>(lastEntryIndex, insp.content);
    } else {
      lastFullContent = new Pair<Integer, byte[]>(lastEntryIndex, new byte[0]);
    }
    assert lastFullContent.first() == lastEntryIndex;
    assert lastFullContent.second() != null;
  }
 
  public static boolean preferCompleteOverPatch(int patchLength, int fullContentLength) {
    return !decideWorthEffort(patchLength, fullContentLength);
  }
 
  public static boolean preferCompressedOverComplete(int compressedLen, int fullContentLength) {
    if (compressedLen <= 0) { // just in case, meaningless otherwise
      return false;
    }
    return decideWorthEffort(compressedLen, fullContentLength);
  }

  // true if length obtained with effort is worth it
  private static boolean decideWorthEffort(int lengthWithExtraEffort, int lengthWithoutEffort) {
    return lengthWithExtraEffort < (/* 3/4 of original */lengthWithoutEffort - (lengthWithoutEffort >>> 2));
  }

  /*XXX public because HgCloneCommand uses it*/
  public static class HeaderWriter implements DataSerializer.DataSource {
    private final ByteBuffer header;
    private final boolean isInline;
    private long offset;
    private int length, compressedLength;
    private int baseRev, linkRev, p1, p2;
    private byte[] nodeid;
   
    public HeaderWriter(boolean inline) {
      isInline = inline;
      header = ByteBuffer.allocate(REVLOGV1_RECORD_SIZE);
    }
   
    public HeaderWriter offset(long offset) {
      this.offset = offset;
      return this;
    }
   
    public int baseRevision() {
      return baseRev;
    }
   
    public HeaderWriter baseRevision(int baseRevision) {
      this.baseRev = baseRevision;
      return this;
    }
   
    public HeaderWriter length(int len, int compressedLen) {
      this.length = len;
      this.compressedLength = compressedLen;
      return this;
    }
   
    public HeaderWriter parents(int parent1, int parent2) {
      p1 = parent1;
      p2 = parent2;
      return this;
    }
   
    public HeaderWriter linkRevision(int linkRevision) {
      linkRev = linkRevision;
      return this;
    }
   
    public HeaderWriter nodeid(Nodeid n) {
      nodeid = n.toByteArray();
      return this;
    }
   
    public HeaderWriter nodeid(byte[] nodeidBytes) {
      nodeid = nodeidBytes;
      return this;
    }
   
    public void serialize(DataSerializer out) throws HgIOException {
      header.clear();
      if (offset == 0) {
        int version = 1 /* RevlogNG */;
        if (isInline) {
          version |= RevlogStream.INLINEDATA;
        }
        header.putInt(version);
        header.putInt(0);
      } else {
        header.putLong(offset << 16);
      }
      header.putInt(compressedLength);
      header.putInt(length);
      header.putInt(baseRev);
      header.putInt(linkRev);
      header.putInt(p1);
      header.putInt(p2);
      header.put(nodeid);
      // assume 12 bytes left are zeros
      out.write(header.array(), 0, header.capacity());

      // regardless whether it's inline or separate data,
      // offset field always represent cumulative compressedLength
      // (while physical offset in the index file with inline==true differs by n*sizeof(header), where n is entry's position in the file)
      offset += compressedLength;
    }
   
    public int serializeLength() {
      return header.capacity();
    }
  }
 
  // XXX part of HgRevisionMap contract, need public counterparts (along with IndexToRevisionMap)
  public interface RevisionToIndexMap {
   
    /**
     * @return {@link HgRepository#NO_REVISION} if unknown revision
     */
    int revisionIndex(Nodeid revision);
  }

  private static class ReadContentInspector implements RevlogStream.Inspector {
    public int baseRev;
    public Nodeid rev;
    public byte[] content;
    private IOException failure;
   
    public ReadContentInspector read(RevlogStream rs, int revIndex) throws HgIOException, HgRuntimeException {
      assert revIndex >= 0;
      rs.iterate(revIndex, revIndex, true, this);
      if (failure != null) {
        String m = String.format("Failed to get content of revision %d", revIndex);
        throw rs.initWithIndexFile(new HgIOException(m, failure, null));
      }
      return this;
    }
   
    public void next(int revisionIndex, int actualLen, int baseRevision, int linkRevision, int parent1Revision, int parent2Revision, byte[] nodeid, DataAccess data) {
      try {
        baseRev = baseRevision;
        rev = Nodeid.fromBinary(nodeid, 0);
        content = data.byteArray();
      } catch (IOException ex) {
        failure = ex;
      }
    }
  }
}
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