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Shawn O. Pearce 06ee913c8d IndexPack: Correct thin pack fix using less than 20 bytes
If we need to append less than 20 bytes in order to fix a thin pack
and make it complete, we need to set the length of our file back to
the actual number of bytes used because the original SHA-1 footer was
not completely overwritten.  That extra data will confuse the header
and footer fixup logic when it tries to read to the end of the file.

This isn't a very common case to occur, which is why we've never
seen it before.  Getting a delta that requires a whole object which
uses less than 20 bytes in pack representation is really hard.
Generally a delta generator won't make these, because the delta
would be bigger than simply deflating the whole object.  I only
managed to do this with a hand-crafted pack file where a 1 byte
delta was pointed to a 1 byte whole object.

Normally we try really hard to avoid truncating, because its
typically not safe across network filesystems.  But the odds of
this occurring are very low.  This truncation is done on a file
we have open for writing, will append more content onto, and is
a temporary file that we won't move into position for others to
see until we've validated its SHA-1 is sane.  I don't think the
truncate on NFS issue is something we need to worry about here.

Change-Id: I102b9637dfd048dc833c050890d142f43c1e75ae
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
2010-04-16 15:56:23 -07:00
org.eclipse.jgit IndexPack: Correct thin pack fix using less than 20 bytes 2010-04-16 15:56:23 -07:00
org.eclipse.jgit.console JGit plugin not compatible with Eclipse 3.4 2010-04-05 12:25:06 +02:00
org.eclipse.jgit.http.server Qualify builds as 0.8.0 2010-03-20 19:06:58 -07:00
org.eclipse.jgit.http.test Qualify builds as 0.8.0 2010-03-20 19:06:58 -07:00
org.eclipse.jgit.iplog Qualify builds as 0.8.0 2010-03-20 19:06:58 -07:00
org.eclipse.jgit.junit JGit plugin not compatible with Eclipse 3.4 2010-04-05 12:25:06 +02:00
org.eclipse.jgit.packaging Merge 'Update build to use Tycho 0.8' 2010-04-10 19:20:48 -07:00
org.eclipse.jgit.pgm Qualify builds as 0.8.0 2010-03-20 19:06:58 -07:00
org.eclipse.jgit.test IndexPack: Correct thin pack fix using less than 20 bytes 2010-04-16 15:56:23 -07:00
org.eclipse.jgit.ui JGit plugin not compatible with Eclipse 3.4 2010-04-05 12:25:06 +02:00
tools tools/version.sh: Update OSGi manifest files 2010-03-18 19:20:32 -07:00
.eclipse_iplog JGit plugin not compatible with Eclipse 3.4 2010-04-05 12:25:06 +02:00
.gitattributes Initial JGit contribution to eclipse.org 2009-09-29 16:47:03 -07:00
LICENSE Initial JGit contribution to eclipse.org 2009-09-29 16:47:03 -07:00
README Initial JGit contribution to eclipse.org 2009-09-29 16:47:03 -07:00
SUBMITTING_PATCHES Correcting explanation of EDL 2009-10-28 14:12:07 +01:00
pom.xml Qualify builds as 0.8.0 2010-03-20 19:06:58 -07:00

README

            == Java GIT ==

This package is licensed under the BSD.

  org.eclipse.jgit/

    A pure Java library capable of being run standalone, with no
    additional support libraries.  Some JUnit tests are provided
    to exercise the library.  The library provides functions to
    read and write a GIT formatted repository.

    All portions of jgit are covered by the BSD.  Absolutely no GPL,
    LGPL or EPL contributions are accepted within this package.

  org.eclipse.jgit.test/
    Unit tests for org.eclipse.jgit and the same licensing rules.

            == WARNINGS / CAVEATS              ==

- Symbolic links are not supported because java does not support it.
  Such links could be damaged.

- Only the timestamp of the index is used by jgit check if  the index
  is dirty.

- Don't try the library with a JDK other than 1.6 (Java 6) unless you
  are prepared to investigate problems yourself. JDK 1.5.0_11 and later
  Java 5 versions *may* work. Earlier versions do not. JDK 1.4 is *not*
  supported. Apple's Java 1.5.0_07 is reported to work acceptably. We
  have no information about other vendors. Please report your findings
  if you try.

- CRLF conversion is never performed. On Windows you should thereforc
  make sure your projects and workspaces are configured to save files
  with Unix (LF) line endings.

            == Package Features                ==

  org.eclipse.jgit/

    * Read loose and packed commits, trees, blobs, including
      deltafied objects.

    * Read objects from shared repositories

    * Write loose commits, trees, blobs.

    * Write blobs from local files or Java InputStreams.

    * Read blobs as Java InputStreams.

    * Copy trees to local directory, or local directory to a tree.

    * Lazily loads objects as necessary.

    * Read and write .git/config files.

    * Create a new repository.

    * Read and write refs, including walking through symrefs.

    * Read, update and write the Git index.

    * Checkout in dirty working directory if trivial.

    * Walk the history from a given set of commits looking for commits
      introducing changes in files under a specified path.

    * Object transport
      Fetch via ssh, git, http, Amazon S3 and bundles.
      Push via ssh, git and Amazon S3. JGit does not yet deltify
      the pushed packs so they may be a lot larger than C Git packs.

  org.eclipse.jgit.pgm/

    * Assorted set of command line utilities. Mostly for ad-hoc testing of jgit
      log, glog, fetch etc.

            == Missing Features                ==

There are a lot of missing features. You need the real Git for this.
For some operations it may just be the preferred solution also. There
are not just a command line, there is e.g. git-gui that makes committing
partial files simple.

- Merging. 

- Repacking.

- Generate a GIT format patch.

- Apply a GIT format patch.

- Documentation. :-)

- gitattributes support
  In particular CRLF conversion is not implemented. Files are treated
  as byte sequences.

- submodule support
  Submodules are not supported or even recognized.

            == Support                         ==

  Post question, comments or patches to the git@vger.kernel.org mailing list.


            == Contributing                    ==

  See SUBMITTING_PATCHES in this directory. However, feedback and bug reports
  are also contributions.


            == About GIT                       ==

More information about GIT, its repository format, and the canonical
C based implementation can be obtained from the GIT websites:

  http://git.or.cz/
  http://www.kernel.org/pub/software/scm/git/
  http://www.kernel.org/pub/software/scm/git/docs/