This prevents a lot of unnecessary warnings about disouraged usage of
the org.eclipse.jgit.internal package within JGit itself.
Change-Id: Ia6683902809425fd7245e7d5d344c2ff8f317ebb
The package was removed in I763590a45d75f00a09097ab6f89581a3bbd3c797
Change-Id: Ifa9e75714f85d17609f9bf61581aaed0631a6fa7
Signed-off-by: Kevin Sawicki <kevin@github.com>
Adds the following commands:
- Add
- Init
- Status
- Sync
- Update
This also updates AddCommand so that file patterns added that
are submodules can be staged in the index.
Change-Id: Ie5112aa26430e5a2a3acd65a7b0e1d76067dc545
Signed-off-by: Kevin Sawicki <kevin@github.com>
Signed-off-by: Chris Aniszczyk <zx@twitter.com>
In practice the DHT storage layer has not been performing as well as
large scale server environments want to see from a Git server.
The performance of the DHT schema degrades rapidly as small changes
are pushed into the repository due to the chunk size being less than
1/3 of the pushed pack size. Small chunks cause poor prefetch
performance during reading, and require significantly longer prefetch
lists inside of the chunk meta field to work around the small size.
The DHT code is very complex (>17,000 lines of code) and is very
sensitive to the underlying database round-trip time, as well as the
way objects were written into the pack stream that was chunked and
stored on the database. A poor pack layout (from any version of C Git
prior to Junio reworking it) can cause the DHT code to be unable to
enumerate the objects of the linux-2.6 repository in a completable
time scale.
Performing a clone from a DHT stored repository of 2 million objects
takes 2 million row lookups in the DHT to locate the OBJECT_INDEX row
for each object being cloned. This is very difficult for some DHTs to
scale, even at 5000 rows/second the lookup stage alone takes 6 minutes
(on local filesystem, this is almost too fast to bother measuring).
Some servers like Apache Cassandra just fall over and cannot complete
the 2 million lookups in rapid fire.
On a ~400 MiB repository, the DHT schema has an extra 25 MiB of
redundant data that gets downloaded to the JGit process, and that is
before you consider the cost of the OBJECT_INDEX table also being
fully loaded, which is at least 223 MiB of data for the linux kernel
repository. In the DHT schema answering a `git clone` of the ~400 MiB
linux kernel needs to load 248 MiB of "index" data from the DHT, in
addition to the ~400 MiB of pack data that gets sent to the client.
This is 193 MiB more data to be accessed than the native filesystem
format, but it needs to come over a much smaller pipe (local Ethernet
typically) than the local SATA disk drive.
I also never got around to writing the "repack" support for the DHT
schema, as it turns out to be fairly complex to safely repack data in
the repository while also trying to minimize the amount of changes
made to the database, due to very common limitations on database
mutation rates..
This new DFS storage layer fixes a lot of those issues by taking the
simple approach for storing relatively standard Git pack and index
files on an abstract filesystem. Packs are accessed by an in-process
buffer cache, similar to the WindowCache used by the local filesystem
storage layer. Unlike the local file IO, there are some assumptions
that the storage system has relatively high latency and no concept of
"file handles". Instead it looks at the file more like HTTP byte range
requests, where a read channel is a simply a thunk to trigger a read
request over the network.
The DFS code in this change is still abstract, it does not store on
any particular filesystem, but is fairly well suited to the Amazon S3
or Apache Hadoop HDFS. Storing packs directly on HDFS rather than
HBase removes a layer of abstraction, as most HBase row reads turn
into an HDFS read.
Most of the DFS code in this change was blatently copied from the
local filesystem code. Most parts should be refactored to be shared
between the two storage systems, but right now I am hesistent to do
this due to how well tuned the local filesystem code currently is.
Change-Id: Iec524abdf172e9ec5485d6c88ca6512cd8a6eafb
BlameGenerator digs through history and discovers the origin of each
line of some result file. BlameResult consumes the stream of regions
created by the generator and lays them out in a table for applications
to display alongside of source lines.
Applications may optionally push in the working tree copy of a file
using the push(String, byte[]) method, allowing the application to
receive accurate line annotations for the working tree version. Lines
that are uncommitted (difference between HEAD and working tree) will
show up with the description given by the application as the author,
or "Not Committed Yet" as a default string.
Applications may also run the BlameGenerator in reverse mode using the
reverse(AnyObjectId, AnyObjectId) method instead of push(). When
running in the reverse mode the generator annotates lines by the
commit they are removed in, rather than the commit they were added in.
This allows a user to discover where a line disappeared from when they
are looking at an older revision in the repository. For example:
blame --reverse 16e810b2..master -L 1080, org.eclipse.jgit.test/tst/org/eclipse/jgit/storage/file/RefDirectoryTest.java
( 1080) }
2302a6d3 (Christian Halstrick 2011-05-20 11:18:20 +0200 1081)
2302a6d3 (Christian Halstrick 2011-05-20 11:18:20 +0200 1082) /**
2302a6d3 (Christian Halstrick 2011-05-20 11:18:20 +0200 1083) * Kick the timestamp of a local file.
Above we learn that line 1080 (a closing curly brace of the prior
method) still exists in branch master, but the Javadoc comment below
it has been removed by Christian Halstrick on May 20th as part of
commit 2302a6d3. This result differs considerably from that of C
Git's blame --reverse feature. JGit tells the reader which commit
performed the delete, while C Git tells the reader the last commit
that still contained the line, leaving it an exercise to the reader
to discover the descendant that performed the removal.
This is still only a basic implementation. Quite notably it is
missing support for the smart block copy/move detection that the C
implementation of `git blame` is well known for. Despite being
incremental, the BlameGenerator can only be run once. After the
generator runs it cannot be reused. A better implementation would
support applications browsing through history efficiently.
In regards to CQ 5110, only a little of the original code survives.
CQ: 5110
Bug: 306161
Change-Id: I84b8ea4838bb7d25f4fcdd540547884704661b8f
Signed-off-by: Kevin Sawicki <kevin@github.com>
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
Signed-off-by: Chris Aniszczyk <caniszczyk@gmail.com>
Using a resolver and factory pattern for the anonymous git:// Daemon
class makes transport.Daemon more useful on non-file storage systems,
or in embedded applications where the caller wants more precise
control over the work tasks constructed within the daemon.
Rather than defining new interfaces, move the existing HTTP ones
into transport.resolver and make them generic on the connection
handle type. For HTTP, continue to use HttpServletRequest, and
for transport.Daemon use DaemonClient.
To remain compatible with transport.Daemon, FileResolver needs to
learn how to use multiple base directories, and how to export any
Repository instance at a fixed name.
Change-Id: I1efa6b2bd7c6567e983fbbf346947238ea2e847e
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
Robin Rosenberg
Matthias Sohn
Tomasz Zarna
Kevin Sawicki
Shawn O. Pearce