e60b9e1879
Increase the safety factor to 2.5x for extra safety if max of measured
timestamp resolution and measured minimal racy threshold is < 100ms, use
1.25 otherwise since for large filesystem resolution values the
influence of finite resolution of the system clock should be negligible.
Before, not yet using the newly introduced minRacyThreshold measurement,
the threshold was 1.1x FS resolution, and we could issue the
following sequence of events,
start
create-file
read-file (currentTime)
end
which had the following timestamps:
create-file 1564589081998
start 1564589082002
read 1564589082003
end 1564589082004
In this case, the difference between create-file and read is 5ms,
which exceeded the 4ms FS resolution, even though the events together
took just 2ms of runtime.
Reproduce with:
bazel test --runs_per_test=100 \
//org.eclipse.jgit.test:org_eclipse_jgit_internal_storage_file_FileSnapshotTest
The file system timestamp resolution is 4ms in this case.
This code assumes that the kernel and the JVM use the same clock that
is synchronized with the file system clock. This seems plausible,
given the resolution of System.currentTimeMillis() and the latency for
a gettimeofday system call (typically ~1us), but it would be good to
justify this with specifications.
Also cover a source of flakiness: if the test runs under extreme load,
then we could have
start
create-file
<long delay>
read
end
which would register as an unmodified file. Avoid this by skipping the
test if end-start is too big.
[msohn]:
- downported from master to stable-5.1
- skip test if resolution is below 10ms
- adjust safety factor to 1.25 for resolutions above 100ms
Change-Id: I87d2cf035e01c44b7ba8364c410a860aa8e312ef
Signed-off-by: Han-Wen Nienhuys <hanwen@google.com>
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>
|
||
|---|---|---|
| .mvn | ||
| Documentation/technical | ||
| lib | ||
| org.eclipse.jgit | ||
| org.eclipse.jgit.ant | ||
| org.eclipse.jgit.ant.test | ||
| org.eclipse.jgit.archive | ||
| org.eclipse.jgit.http.apache | ||
| org.eclipse.jgit.http.server | ||
| org.eclipse.jgit.http.test | ||
| org.eclipse.jgit.junit | ||
| org.eclipse.jgit.junit.http | ||
| org.eclipse.jgit.lfs | ||
| org.eclipse.jgit.lfs.server | ||
| org.eclipse.jgit.lfs.server.test | ||
| org.eclipse.jgit.lfs.test | ||
| org.eclipse.jgit.packaging | ||
| org.eclipse.jgit.pgm | ||
| org.eclipse.jgit.pgm.test | ||
| org.eclipse.jgit.test | ||
| org.eclipse.jgit.ui | ||
| tools | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| BUILD | ||
| CONTRIBUTING.md | ||
| LICENSE | ||
| README.md | ||
| WORKSPACE | ||
| pom.xml | ||
README.md
Java Git
An implementation of the Git version control system in pure Java.
This package is licensed under the EDL (Eclipse Distribution License).
JGit can be imported straight into Eclipse, built and tested from there, but the automated builds use Maven.
-
org.eclipse.jgit
A pure Java library capable of being run standalone, with no additional support libraries. It provides classes to read and write a Git repository and operate on a working directory.
All portions of JGit are covered by the EDL. Absolutely no GPL, LGPL or EPL contributions are accepted within this package.
-
org.eclipse.jgit.ant
Ant tasks based on JGit.
-
org.eclipse.jgit.archive
Support for exporting to various archive formats (zip etc).
-
org.eclipse.jgit.http.apache
Apache httpclient support
-
org.eclipse.jgit.http.server
Server for the smart and dumb Git HTTP protocol.
-
org.eclipse.jgit.pgm
Command-line interface Git commands implemented using JGit ("pgm" stands for program).
-
org.eclipse.jgit.packaging
Production of Eclipse features and p2 repository for JGit. See the JGit Wiki on why and how to use this module.
Tests
-
org.eclipse.jgit.junit
Helpers for unit testing
-
org.eclipse.jgit.test
Unit tests for org.eclipse.jgit
-
org.eclipse.jgit.ant.test
-
org.eclipse.jgit.pgm.test
-
org.eclipse.jgit.http.test
-
org.eclipse.jgit.junit.test
No further description needed
Warnings/Caveats
-
Native smbolic links are supported, provided the file system supports them. For Windows you must have Windows Vista/Windows 2008 or newer, use a non-administrator account and have the SeCreateSymbolicLinkPrivilege.
-
Only the timestamp of the index is used by jgit if the index is dirty.
-
JGit requires at least a Java 8 JDK.
-
CRLF conversion is performed depending on the core.autocrlf setting, however Git for Windows by default stores that setting during installation in the "system wide" configuration file. If Git is not installed, use the global or repository configuration for the core.autocrlf setting.
-
The system wide configuration file is located relative to where C Git is installed. Make sure Git can be found via the PATH environment variable. When installing Git for Windows check the "Run Git from the Windows Command Prompt" option. There are other options like Eclipse settings that can be used for pointing out where C Git is installed. Modifying PATH is the recommended option if C Git is installed.
-
We try to use the same notation of $HOME as C Git does. On Windows this is often not the same value as the user.home system property.
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.
-
Garbage collection
-
Merge
-
Rebase
-
And much more
-
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org.eclipse.jgit.pgm/
- Assorted set of command line utilities. Mostly for ad-hoc testing of jgit log, glog, fetch etc.
-
org.eclipse.jgit.ant/
- Ant tasks
-
org.eclipse.jgit.archive/
- Support for Zip/Tar and other formats
-
org.eclipse.http.*/
- HTTP client and server support
Missing Features
There are some missing features:
- gitattributes support
Support
Post question, comments or patches to the jgit-dev@eclipse.org mailing list. You need to be subscribed to post, see here:
https://dev.eclipse.org/mailman/listinfo/jgit-dev
Contributing
See the EGit Contributor Guide:
http://wiki.eclipse.org/EGit/Contributor_Guide
About Git
More information about Git, its repository format, and the canonical C based implementation can be obtained from the Git website: