Package org.tmatesoft.hg.repo

Source Code of org.tmatesoft.hg.repo.HgDataFile$MetadataInspector

/*
* Copyright (c) 2010-2013 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.repo;

import static org.tmatesoft.hg.repo.HgInternals.wrongRevisionIndex;
import static org.tmatesoft.hg.repo.HgRepository.*;
import static org.tmatesoft.hg.util.LogFacility.Severity.Info;

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.channels.FileChannel;
import java.util.Arrays;

import org.tmatesoft.hg.core.HgChangesetFileSneaker;
import org.tmatesoft.hg.core.HgFileRevision;
import org.tmatesoft.hg.core.Nodeid;
import org.tmatesoft.hg.internal.DataAccess;
import org.tmatesoft.hg.internal.FileUtils;
import org.tmatesoft.hg.internal.FilterByteChannel;
import org.tmatesoft.hg.internal.FilterDataAccess;
import org.tmatesoft.hg.internal.Internals;
import org.tmatesoft.hg.internal.Metadata;
import org.tmatesoft.hg.internal.RevlogStream;
import org.tmatesoft.hg.util.ByteChannel;
import org.tmatesoft.hg.util.CancelSupport;
import org.tmatesoft.hg.util.CancelledException;
import org.tmatesoft.hg.util.LogFacility;
import org.tmatesoft.hg.util.Pair;
import org.tmatesoft.hg.util.Path;
import org.tmatesoft.hg.util.ProgressSupport;


/**
* Regular user data file stored in the repository.
*
* <p> Note, most methods accept index in the file's revision history, not that of changelog. Easy way to obtain
* changeset revision index from file's is to use {@link #getChangesetRevisionIndex(int)}. To obtain file's revision
* index for a given changeset, {@link HgManifest#getFileRevision(int, Path)} or {@link HgChangesetFileSneaker} may
* come handy.
*
* @author Artem Tikhomirov
* @author TMate Software Ltd.
*/
public final class HgDataFile extends Revlog {

  // absolute from repo root?
  // slashes, unix-style?
  // repo location agnostic, just to give info to user, not to access real storage
  private final Path path;
  /*
   * Get initialized on first access to file content.
   * We read metadata starting from rev 0 always, so that Metadata#lastRevisionRead()
   * shows the region of file history [0..lastRevisionRead] we know metadata for
   */
  private Metadata metadata;
 
  /*package-local*/HgDataFile(HgRepository hgRepo, Path filePath, RevlogStream content) {
    super(hgRepo, content, false);
    path = filePath;
  }

  // exists is not the best name possible. now it means no file with such name was ever known to the repo.
  // it might be confused with files existed before but lately removed. TODO HgFileNode.exists makes more sense.
  // or HgDataFile.known()
  public boolean exists() {
    return content.exists();
  }

  /**
   * Human-readable file name, i.e. "COPYING", not "store/data/_c_o_p_y_i_n_g.i"
   */
  public Path getPath() {
    return path; // hgRepo.backresolve(this) -> name? In this case, what about hashed long names?
  }

  /**
   * Handy shorthand for {@link #getLength(int) length(getRevisionIndex(nodeid))}
   *
   * @param nodeid revision of the file
   *
   * @return size of the file content at the given revision
   * @throws HgRuntimeException subclass thereof to indicate issues with the library. <em>Runtime exception</em>
   */
  public int getLength(Nodeid nodeid) throws HgRuntimeException {
    try {
      return getLength(getRevisionIndex(nodeid));
    } catch (HgInvalidControlFileException ex) {
      throw ex.isRevisionSet() ? ex : ex.setRevision(nodeid);
    } catch (HgInvalidRevisionException ex) {
      throw ex.isRevisionSet() ? ex : ex.setRevision(nodeid);
    }
  }
 
  /**
    * @param fileRevisionIndex - revision local index, non-negative. From predefined constants, only {@link HgRepository#TIP} makes sense.
   * @return size of the file content at the revision identified by local revision number.
   * @throws HgRuntimeException subclass thereof to indicate issues with the library. <em>Runtime exception</em>
   */
  public int getLength(int fileRevisionIndex) throws HgRuntimeException {
    if (wrongRevisionIndex(fileRevisionIndex) || fileRevisionIndex == BAD_REVISION) {
      throw new HgInvalidRevisionException(fileRevisionIndex);
    }
    if (fileRevisionIndex == TIP) {
      fileRevisionIndex = getLastRevision();
    } else if (fileRevisionIndex == WORKING_COPY) {
      File f = getRepo().getFile(this);
      if (f.exists()) {
        // single revision can't be greater than 2^32, shall be safe to cast to int
        return Internals.ltoi(f.length());
      }
      Nodeid fileRev = getWorkingCopyRevision();
      if (fileRev == null) {
        throw new HgInvalidRevisionException(String.format("File %s is not part of working copy", getPath()), null, fileRevisionIndex);
      }
      fileRevisionIndex = getRevisionIndex(fileRev);
    }
    if (metadata == null || !metadata.checked(fileRevisionIndex)) {
      checkAndRecordMetadata(fileRevisionIndex);
    }
    final int dataLen = content.dataLength(fileRevisionIndex);
    if (metadata.known(fileRevisionIndex)) {
      return dataLen - metadata.dataOffset(fileRevisionIndex);
    }
    return dataLen;
  }
 
  /**
   * Reads content of the file from working directory. If file present in the working directory, its actual content without
   * any filters is supplied through the sink. If file does not exist in the working dir, this method provides content of a file
   * as if it would be refreshed in the working copy, i.e. its corresponding revision (according to dirstate) is read from the
   * repository, and filters repo -> working copy get applied.
   *
   * NOTE, if file is missing from the working directory and is not part of the dirstate (but otherwise legal repository file,
   * e.g. from another branch), no content would be supplied.
   *    
   * @param sink content consumer
   * @throws CancelledException if execution of the operation was cancelled
   * @throws HgRuntimeException subclass thereof to indicate issues with the library. <em>Runtime exception</em>
   */
  public void workingCopy(ByteChannel sink) throws CancelledException, HgRuntimeException {
    File f = getRepo().getFile(this);
    if (f.exists()) {
      final CancelSupport cs = CancelSupport.Factory.get(sink);
      final ProgressSupport progress = ProgressSupport.Factory.get(sink);
      final long flength = f.length();
      final int bsize = (int) Math.min(flength, 32*1024);
      progress.start((int) (flength > Integer.MAX_VALUE ? flength >>> 15 /*32 kb buf size*/ : flength));
      ByteBuffer buf = ByteBuffer.allocate(bsize);
      FileInputStream fis = null;
      try {
        fis = new FileInputStream(f);
        FileChannel fc = fis.getChannel();
        while (fc.read(buf) != -1) {
          cs.checkCancelled();
          buf.flip();
          int consumed = sink.write(buf);
          progress.worked(flength > Integer.MAX_VALUE ? 1 : consumed);
          buf.compact();
        }
      } catch (IOException ex) {
        throw new HgInvalidFileException("Working copy read failed", ex, f);
      } finally {
        progress.done();
        if (fis != null) {
          new FileUtils(getRepo().getSessionContext().getLog(), this).closeQuietly(fis);
        }
      }
    } else {
      Nodeid fileRev = getWorkingCopyRevision();
      if (fileRev == null) {
        // no content for this data file in the working copy - it is not part of the actual working state.
        // XXX perhaps, shall report this to caller somehow, not silently pass no data?
        return;
      }
      final int fileRevIndex = getRevisionIndex(fileRev);
      contentWithFilters(fileRevIndex, sink);
    }
  }
 
  /**
   * @return file revision as recorded in repository manifest for dirstate parent, or <code>null</code> if no file revision can be found
   * @throws HgInvalidControlFileException if failed to access revlog index/data entry. <em>Runtime exception</em>
   * @throws HgRuntimeException subclass thereof to indicate other issues with the library. <em>Runtime exception</em>
   */
  private Nodeid getWorkingCopyRevision() throws HgRuntimeException {
    final Pair<Nodeid, Nodeid> wcParents = getRepo().getWorkingCopyParents();
    Nodeid p = wcParents.first().isNull() ? wcParents.second() : wcParents.first();
    final HgChangelog clog = getRepo().getChangelog();
    final int csetRevIndex;
    if (p.isNull()) {
      // no dirstate parents
      getRepo().getSessionContext().getLog().dump(getClass(), Info, "No dirstate parents, resort to TIP", getPath());
      // if it's a repository with no dirstate, use TIP then
      csetRevIndex = clog.getLastRevision();
      if (csetRevIndex == -1) {
        // shall not happen provided there's .i for this data file (hence at least one cset)
        // and perhaps exception is better here. However, null as "can't find" indication seems reasonable.
        return null;
      }
    } else {
      // common case to avoid searching complete changelog for nodeid match
      final Nodeid tipRev = clog.getRevision(TIP);
      if (tipRev.equals(p)) {
        csetRevIndex = clog.getLastRevision();
      } else {
        // bad luck, need to search honestly
        csetRevIndex = clog.getRevisionIndex(p);
      }
    }
    Nodeid fileRev = getRepo().getManifest().getFileRevision(csetRevIndex, getPath());
    // it's possible for a file to be in working dir and have store/.i but to belong e.g. to a different
    // branch than the one from dirstate. Thus it's possible to get null fileRev
    // which would serve as an indication this data file is not part of working copy
    return fileRev;
  }
 
  /**
   * Access content of a file revision
   * XXX not sure distinct method contentWithFilters() is the best way to do, perhaps, callers shall add filters themselves?
   *
    * @param fileRevisionIndex - revision local index, non-negative. From predefined constants, {@link HgRepository#TIP} and {@link HgRepository#WORKING_COPY} make sense.
   * @param sink content consumer
   *
   * @throws CancelledException if execution of the operation was cancelled
   * @throws HgRuntimeException subclass thereof to indicate issues with the library. <em>Runtime exception</em>
   */
  public void contentWithFilters(int fileRevisionIndex, ByteChannel sink) throws CancelledException, HgRuntimeException {
    if (fileRevisionIndex == WORKING_COPY) {
      workingCopy(sink); // pass un-mangled sink
    } else {
      content(fileRevisionIndex, new FilterByteChannel(sink, getRepo().getFiltersFromRepoToWorkingDir(getPath())));
    }
  }

  /**
   * Retrieve content of specific revision. Content is provided as is, without any filters (e.g. keywords, eol, etc.) applied.
   * For filtered content, use {@link #contentWithFilters(int, ByteChannel)}.
   *
    * @param fileRevisionIndex - revision local index, non-negative. From predefined constants, {@link HgRepository#TIP} and {@link HgRepository#WORKING_COPY} make sense.
   * @param sink content consumer
   *
   * @throws CancelledException if execution of the operation was cancelled
   * @throws HgRuntimeException subclass thereof to indicate issues with the library. <em>Runtime exception</em>
   */
  public void content(int fileRevisionIndex, ByteChannel sink) throws CancelledException, HgRuntimeException {
    // for data files need to check heading of the file content for possible metadata
    // @see http://mercurial.selenic.com/wiki/FileFormats#data.2BAC8-
    if (fileRevisionIndex == TIP) {
      fileRevisionIndex = getLastRevision();
    }
    if (fileRevisionIndex == WORKING_COPY) {
      // sink is supposed to come into workingCopy without filters
      // thus we shall not get here (into #content) from #contentWithFilters(WC)
      workingCopy(sink);
      return;
    }
    if (wrongRevisionIndex(fileRevisionIndex) || fileRevisionIndex == BAD_REVISION) {
      throw new HgInvalidRevisionException(fileRevisionIndex);
    }
    if (sink == null) {
      throw new IllegalArgumentException();
    }
    if (metadata == null) {
      metadata = new Metadata(getRepo());
    }
    ErrorHandlingInspector insp;
    final LogFacility lf = getRepo().getSessionContext().getLog();
    if (metadata.none(fileRevisionIndex)) {
      insp = new ContentPipe(sink, 0, lf);
    } else if (metadata.known(fileRevisionIndex)) {
      insp = new ContentPipe(sink, metadata.dataOffset(fileRevisionIndex), lf);
    } else {
      // do not know if there's metadata
      insp = new MetadataInspector(metadata, new ContentPipe(sink, 0, lf));
    }
    insp.checkCancelled();
    super.content.iterate(fileRevisionIndex, fileRevisionIndex, true, insp);
    try {
      insp.checkFailed();
    } catch (HgInvalidControlFileException ex) {
      ex = ex.setFileName(getPath());
      throw ex.isRevisionIndexSet() ? ex : ex.setRevisionIndex(fileRevisionIndex);
    } catch (IOException ex) {
      HgInvalidControlFileException e = new HgInvalidControlFileException("Revision content access failed", ex, null);
      throw content.initWithIndexFile(e).setFileName(getPath()).setRevisionIndex(fileRevisionIndex);
    }
  }

  /**
   * Walk complete change history of the file.
   * @param inspector callback to visit changesets
   * @throws HgRuntimeException subclass thereof to indicate issues with the library. <em>Runtime exception</em>
   */
  public void history(HgChangelog.Inspector inspector) throws HgRuntimeException {
    history(0, getLastRevision(), inspector);
  }

  /**
   * Walk subset of the file's change history.
   * @param start revision local index, inclusive; non-negative or {@link HgRepository#TIP}
   * @param end revision local index, inclusive; non-negative or {@link HgRepository#TIP}
   * @param inspector callback to visit changesets
   * @throws HgRuntimeException subclass thereof to indicate issues with the library. <em>Runtime exception</em>
   */
  public void history(int start, int end, HgChangelog.Inspector inspector) throws HgRuntimeException {
    if (!exists()) {
      throw new IllegalStateException("Can't get history of invalid repository file node");
    }
    final int last = getLastRevision();
    if (end == TIP) {
      end = last;
    }
    if (start == TIP) {
      start = last;
    }
    HgInternals.checkRevlogRange(start, end, last);

    final int[] commitRevisions = new int[end - start + 1];
    final boolean[] needsSorting = { false };
    RevlogStream.Inspector insp = new RevlogStream.Inspector() {
      int count = 0;
      public void next(int revisionNumber, int actualLen, int baseRevision, int linkRevision, int parent1Revision, int parent2Revision, byte[] nodeid, DataAccess data) {
        if (count > 0) {
          if (commitRevisions[count -1] > linkRevision) {
            needsSorting[0] = true;
          }
        }
        commitRevisions[count++] = linkRevision;
      }
    };
    content.iterate(start, end, false, insp);
    final HgChangelog changelog = getRepo().getChangelog();
    if (needsSorting[0]) {
      // automatic tools (svnmerge?) produce unnatural file history
      // (e.g. cpython/Lib/doctest.py, revision 164 points to cset 63509, 165 - to 38453)
      Arrays.sort(commitRevisions);
    }
    changelog.rangeInternal(inspector, commitRevisions);
  }
 
  /**
   * For a given revision of the file (identified with revision index), find out index of the corresponding changeset.
   *
   * @return changeset revision index
   * @throws HgRuntimeException subclass thereof to indicate issues with the library. <em>Runtime exception</em>
   */
  public int getChangesetRevisionIndex(int fileRevisionIndex) throws HgRuntimeException {
    return content.linkRevision(fileRevisionIndex);
  }

  /**
   * Complements {@link #getChangesetRevisionIndex(int)} to get changeset revision that corresponds to supplied file revision
   *
   * @param nid revision of the file
   * @return changeset revision
   * @throws HgRuntimeException subclass thereof to indicate issues with the library. <em>Runtime exception</em>
   */
  public Nodeid getChangesetRevision(Nodeid nid) throws HgRuntimeException {
    int changelogRevision = getChangesetRevisionIndex(getRevisionIndex(nid));
    return getRepo().getChangelog().getRevision(changelogRevision);
  }

  /**
   * Tells whether first revision of this file originates from another repository file.
   * This method is shorthand for {@link #isCopy(int) isCopy(0)} and it's advised to use {@link #isCopy(int)} instead.
   * 
   * @return <code>true</code> if first revision of this file is a copy of some other from the repository
   * @throws HgRuntimeException subclass thereof to indicate issues with the library. <em>Runtime exception</em>
   */
  public boolean isCopy() throws HgRuntimeException {
    return isCopy(0);
  }

  /**
   * Get name of the file first revision of this one was copied from.
   * Note, it's better to use {@link #getCopySource(int)} instead.
   *
   * @return name of the file origin
   * @throws HgRuntimeException subclass thereof to indicate issues with the library. <em>Runtime exception</em>
   */
  public Path getCopySourceName() throws HgRuntimeException {
    if (isCopy()) {
      Path.Source ps = getRepo().getSessionContext().getPathFactory();
      return ps.path(metadata.find(0, "copy"));
    }
    throw new UnsupportedOperationException(); // XXX REVISIT, think over if Exception is good (clients would check isCopy() anyway, perhaps null is sufficient?)
  }
 
  /**
   * Use {@link #getCopySource(int)} instead
   * @return revision this file was copied from
   * @throws HgRuntimeException subclass thereof to indicate issues with the library. <em>Runtime exception</em>
   */
  public Nodeid getCopySourceRevision() throws HgRuntimeException {
    if (isCopy()) {
      return Nodeid.fromAscii(metadata.find(0, "copyrev")); // XXX reuse/cache Nodeid
    }
    throw new UnsupportedOperationException();
  }
 
  /**
   * Tell if specified file revision was created by copying or renaming another file
   *
   * @param fileRevisionIndex index of file revision to check
   * @return <code>true</code> if this revision originates (as a result of copy/rename) from another file
   * @throws HgRuntimeException subclass thereof to indicate issues with the library. <em>Runtime exception</em>
   * @since 1.2
   */
  public boolean isCopy(int fileRevisionIndex) throws HgRuntimeException {
    if (fileRevisionIndex == TIP) {
      fileRevisionIndex = getLastRevision();
    }
    if (wrongRevisionIndex(fileRevisionIndex) || fileRevisionIndex == BAD_REVISION || fileRevisionIndex == WORKING_COPY || fileRevisionIndex == NO_REVISION) {
      throw new HgInvalidRevisionException(fileRevisionIndex);
    }
   
    if (metadata == null || !metadata.checked(fileRevisionIndex)) {
      checkAndRecordMetadata(fileRevisionIndex);
    }
    if (!metadata.known(fileRevisionIndex)) {
      return false;
    }
    return metadata.find(fileRevisionIndex, "copy") != null;
  }
 
  /**
   * Find out which file and which revision of that file given revision originates from
   *
   * @param fileRevisionIndex file revision index of interest, it's assumed {@link #isCopy(int)} for the same revision is <code>true</code>
   * @return origin revision descriptor
   * @throws HgRuntimeException
   * @throws UnsupportedOperationException if specified revision is not a {@link #isCopy(int) copy} revision
   * @since 1.2
   */
  public HgFileRevision getCopySource(int fileRevisionIndex) throws HgRuntimeException {
    if (fileRevisionIndex == TIP) {
      fileRevisionIndex = getLastRevision();
    }
    if (!isCopy(fileRevisionIndex)) {
      throw new UnsupportedOperationException();
    }
    Path.Source ps = getRepo().getSessionContext().getPathFactory();
    Path origin = ps.path(metadata.find(fileRevisionIndex, "copy"));
    Nodeid originRev = Nodeid.fromAscii(metadata.find(fileRevisionIndex, "copyrev")); // XXX reuse/cache Nodeid
    return new HgFileRevision(getRepo(), originRev, null, origin);
  }

  /**
   * Get file flags recorded in the manifest
    * @param fileRevisionIndex - revision local index, non-negative, or {@link HgRepository#TIP}.
   * @see HgManifest#getFileFlags(int, Path)
   * @throws HgRuntimeException subclass thereof to indicate issues with the library. <em>Runtime exception</em>
   */
  public HgManifest.Flags getFlags(int fileRevisionIndex) throws HgRuntimeException {
    int changesetRevIndex = getChangesetRevisionIndex(fileRevisionIndex);
    return getRepo().getManifest().getFileFlags(changesetRevIndex, getPath());
  }

  @Override
  public String toString() {
    StringBuilder sb = new StringBuilder(getClass().getSimpleName());
    sb.append('(');
    sb.append(getPath());
    sb.append(')');
    return sb.toString();
  }
 
  private void checkAndRecordMetadata(int localRev) throws HgRuntimeException {
    int startRev;
    if (metadata == null) {
      metadata = new Metadata(getRepo());
      startRev = 0; // read from the very beginning with one shot - likely isCopy(localRev-i) will be of interest, too
    } else {
      startRev = metadata.lastRevisionRead() + 1;
    }
    assert localRev >= startRev; // callers of this method ensure that metadata has been checked beforehand
    // use MetadataInspector without delegate to process metadata only
    RevlogStream.Inspector insp = new MetadataInspector(metadata, null);
    super.content.iterate(startRev, localRev, true, insp);
  }

  private static class MetadataInspector extends ErrorHandlingInspector implements RevlogStream.Inspector {
    private final Metadata metadata;
    private final RevlogStream.Inspector delegate;

    /**
     * @param _metadata never <code>null</code>
     * @param chain <code>null</code> if no further data processing other than metadata is desired
     */
    public MetadataInspector(Metadata _metadata, RevlogStream.Inspector chain) {
      metadata = _metadata;
      delegate = chain;
      setCancelSupport(CancelSupport.Factory.get(chain));
    }

    public void next(int revisionNumber, int actualLen, int baseRevision, int linkRevision, int parent1Revision, int parent2Revision, byte[] nodeid, DataAccess data) throws HgRuntimeException {
      try {
        final boolean gotMetadata = metadata.tryRead(revisionNumber, data);
        if (delegate != null) {
          data.reset();
          if (gotMetadata) {
            // da is in prepared state (i.e. we consumed all bytes up to metadata end).
            // However, it's not safe to assume delegate won't call da.reset() for some reason,
            // and we need to ensure predictable result.
            int offset = metadata.dataOffset(revisionNumber);
            data = new FilterDataAccess(data, offset, data.length() - offset);
          }
          delegate.next(revisionNumber, actualLen, baseRevision, linkRevision, parent1Revision, parent2Revision, nodeid, data);
        }
      } catch (IOException ex) {
        recordFailure(ex);
      } catch (HgInvalidControlFileException ex) {
        recordFailure(ex.isRevisionIndexSet() ? ex : ex.setRevisionIndex(revisionNumber));
      }
    }

    @Override
    public void checkFailed() throws HgRuntimeException, IOException, CancelledException {
      super.checkFailed();
      if (delegate instanceof ErrorHandlingInspector) {
        // TODO need to add ErrorDestination (ErrorTarget/Acceptor?) and pass it around (much like CancelSupport get passed)
        // so that delegate would be able report its failures directly to caller without this hack
        ((ErrorHandlingInspector) delegate).checkFailed();
      }
    }
  }
}
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