f5fe2dca3c
Counting the objects needed for packing is the most expensive part of an UploadPack request that has no uninteresting objects (otherwise known as an initial clone). During this phase the PackWriter is enumerating the entire set of objects in this repository, so they can be sent to the client for their new clone. Allow the ObjectReader (and therefore the underlying storage system) to keep a cached list of all reachable objects from a small number of points in the project's history. If one of those points is reached during enumeration of the commit graph, most objects are obtained from the cached list instead of direct traversal. PackWriter uses the list by discarding the current object lists and restarting a traversal from all refs but marking the object list name as uninteresting. This allows PackWriter to enumerate all objects that are more recent than the list creation, or that were on side branches that the list does not include. However, ObjectWalk tags all of the trees and commits within the list commit as UNINTERESTING, which would normally cause PackWriter to construct a thin pack that excludes these objects. To avoid that, addObject() was refactored to allow this list-based enumeration to always include an object, even if it has been tagged UNINTERESTING by the ObjectWalk. This implies the list-based enumeration may only be used for initial clones, where all objects are being sent. The UNINTERESTING labeling occurs because StartGenerator always enables the BoundaryGenerator if the walker is an ObjectWalk and a commit was marked UNINTERESTING, even if RevSort.BOUNDARY was not enabled. This is the default reasonable behavior for an ObjectWalk, but isn't desired here in PackWriter with the list-based enumeration. Rather than trying to change all of this behavior, PackWriter works around it. Because the list name commit's immediate files and trees were all enumerated before the list enumeration itself starts (and are also within the list itself) PackWriter runs the risk of adding the same objects to its ObjectIdSubclassMap twice. Since this breaks the internal map data structure (and also may cause the object to transmit twice), PackWriter needs to use a new "added" RevFlag to track whether or not an object has been put into the outgoing list yet. Change-Id: Ie99ed4d969a6bb20cc2528ac6b8fb91043cee071 Signed-off-by: Shawn O. Pearce <spearce@spearce.org> |
||
|---|---|---|
| org.eclipse.jgit | ||
| org.eclipse.jgit.console | ||
| org.eclipse.jgit.http.server | ||
| org.eclipse.jgit.http.test | ||
| org.eclipse.jgit.iplog | ||
| org.eclipse.jgit.junit | ||
| org.eclipse.jgit.junit.http | ||
| org.eclipse.jgit.packaging | ||
| org.eclipse.jgit.pgm | ||
| org.eclipse.jgit.test | ||
| org.eclipse.jgit.ui | ||
| tools | ||
| .eclipse_iplog | ||
| .gitattributes | ||
| LICENSE | ||
| README | ||
| SUBMITTING_PATCHES | ||
| pom.xml | ||
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/