There is a potential race condition during insertPack that can lead
to us having the same pack file open twice in the same directory.

A different thread can miss an object on disk, and trigger a scan
of the directory, and notice the pack that was put in by IndexPack.
So the pack winds up in the newly created PackList.

The IndexPack thread then wakes up and finishes its insertPack by
creating a new PackFile and inserting it into position 0 of the list.
We now have the same pack listed twice.

Readers will favor the earlier PackFile instance, because its the
first one they come across as they iterate through the list.

Keep that earlier one when we scan the pack directory again, as
this will avoid needing to purge out all of the windows that may
have been cached.

Of course we should also fix that race condition, but this block
was taking the wrong resolution if this error ever shows up, so
lets first fix the block to use a more sane resolution.

Change-Id: I0d339b9fd1dd8012e8fe5a564b893c0f69109e28
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>

This reuse line was identical between the two branches related to
reusing a delta, or reusing a whole object.  Either way they reuse
the body of the object as-is.  So just make that a common function
after the header is written.

Change-Id: I0e6673b8e813c8c08c594ea2ba546fd366339d5d
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>

If a corrupt loose object is read, UnpackedObjectLoader was disposing
of the Inflater, and then attempting to return the disposed Inflater
to the InflaterCache.  Since the disposed Inflater had its native
libz resource deallocated and its reference cleared out, the Inflater
threw NullPointerException and refused to reset itself before being
put back into the cache.

Instead of disposing of the Inflater when corruption is found, do
nothing, and allow it to be returned to the cache.  The instance
will get reset, and should be usable by a future caller.

Bug: 310291
Change-Id: I44f2247c08b6e04fa62f8399609341b07508c096
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>

The Iterator contract says next() shall throw NoSuchElementException
if there are no more items remaining in the iteration.  We got this
wrong when I originally wrote the implementation, so fix it.

Change-Id: Iea25e6569ead5c8b3128b8a368c5b2caebec7ecc
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>

This class behaves like a cross between a Set and a Map, sometimes
we might expect to use the method isEmpty() to test for size() == 0.
So implement it, reducing the surprise folks get when they are given
one of these objects.

Change-Id: I0d68e1243da8e62edf79c6ba4fd925f643e80a88
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>

We can avoid one stat call by trying to perform a directory
listing without checking if the reference File is a directory.
Attempting a directory listing is defined to return. The other
case for null returns from list is when an I/O error occcurs.

Both cases are now intepreted as a possible plain reference. I/O
errors when reading plain references will be handled (ignored)
in scanRef().

Change-Id: I9906ed8c42eab4d6029c781aab87b3b07c1a1d2c
Signed-off-by: Robin Rosenberg <robin.rosenberg@dewire.com>

In the current implementation Repository reads user and repository 
config only at creation point of time.
The new implementatiopn checks in Repository.getConfig if user or 
repository config have changed on disk and reload the config if 
required. 

Change-Id: Ibd97515919ef66c6f8aa1a4fe8a11a6711335dad
Signed-off-by: Jens Baumgart <jens.baumgart@sap.com>

We only need to check file existense if some other stat returns
a value that may mean that the file does not exist. File.length() == 0
or File.lastModified() == 0 are two such properties. We use length
here.

Change-Id: If626b12e7bb4da994b5c086f6a5b7a12c187261c
Signed-off-by: Robin Rosenberg <robin.rosenberg@dewire.com>

Some transports actually provide stream buffering on their own,
without needing to be wrapped up inside of a BufferedInputStream in
order to smooth out system calls to read or write.  A great example
of this is the JSch SSH client, or the Apache MINA SSHD server.
Both use custom buffering to packetize the streams into the encrypted
SSH channel, and wrapping them up inside of a BufferedInputStream
or BufferedOutputStream is relatively pointless.

Our SideBandOutputStream implementation also provides some fairly
large buffering, equal to one complete side-band packet on the main
data channel.  Wrapping that inside of a BufferedOutputStream just to
smooth out small writes from PackWriter causes extra data copies, and
provides no advantage.  We can save some memory and some CPU cycles
by letting PackWriter dump directly into the SideBandOutputStream's
internal buffer array.

Instead we push the buffering streams down to be as close to the
network socket (or operating system pipe) as possible.  This allows
us to smooth out the smaller reads/writes from pkt-line messages
during advertisement and negotation, but avoid copying altogether
when the stream switches to larger writes over a side band channel.

Change-Id: I2f6f16caee64783c77d3dd1b2a41b3cc0c64c159
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>

The initial contribution was handled through a CQ, and does not need
to be reported as an individual bug record in the project's IP log.
Its an odd corner case that the EMO IP team doesn't want to see,
even though its technically a contribution written by at least
some non-committers.

The project.skipCommit variable can now be used to mask out any
particular change from the IP log.  Currently within JGit we want
to mask only the initial commit, but others could be masked if the
need arises.

Change-Id: I598e08137ddc5913284471ee2aa545f4df685023
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>

Windows users by default have core.autocrlf set to true. JGit
does not recognize the flags and thus works as if it is set. In order
to make JGit more compatible with msysgit we set the flag to false
in repositories that JGit creates.

Bug: 301775
Change-Id: I7ea462fe3516e5060b87aa1f7ed63689936830c2
Signed-off-by: Robin Rosenberg <robin.rosenberg@dewire.com>

The unsetSection method can be used to delete an entire configuration
block, such as a [branch ""] or [remote ""] section in a file.

Change-Id: I93390c9b2187eb1b0d51353518feaed83bed2aad
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
Signed-off-by: Robin Rosenberg <robin.rosenberg@dewire.com>

Config was confusing the following two variables when writing the
file back to text format:

  [my]
    empty =
    enabled

When parsed, we say that my.empty has 1 value, null, and my.enabled
is an empty string value that in boolean context should be evaluated
as true.

Saving this configuration file back to text format was ignoring the
null value for my.empty, producing a completely different file than
what Config read:

  [my]
    empty
    enabled

Instead handle the writing differently to ensure the original format
is output.  New tests cases cover the expected behavior and return
values from accessor methods.

Change-Id: Id37379ce20cb27e3330923cf989444dd9f2bdd96
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>

Annotated tags created with C Git versions before the introduction
of c818566 ([PATCH] Update tags to record who made them, 2005-07-14),
do not have a "tagger" line present in the object header.  This line
did not appear in C Git until v0.99.1~9.

Ancient projects such as the Linux kernel contain such tags, for
example Linux 2.6.12 is older than when this feature first appeared
in C Git.  Linux v2.6.13-rc4 in late July 2005 is the first kernel
version tag to actually contain a tagger line.

It is therefore acceptable for the header to be missing, and for
the RevTag.getTaggerIdent() method to return null.

Since the Javadoc for getTaggerIdent() already explained that the
identity may be null, we just need to test that this is true when
the header is missing, and allow the ObjectChecker to pass anyway.

Change-Id: I34ba82e0624a0d1a7edcf62ffba72260af6f7e5d
See: http://code.google.com/p/gerrit/issues/detail?id=399
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>

By using RefUpdate for symbolic reference creation we can reuse
the logic related to updating the reflog with the event, without
needing to expose something such as the legacy ReflogWriter class
(which we no longer have).

Applications using writeSymref must update their code to use the
new pattern of changing the reference through the updateRef method:

    String refName = "refs/heads/master";
    RefUpdate u = repository.updateRef(Constants.HEAD);
    u.setRefLogMessage("checkout: moving to " + refName, false);
    switch (u.link(refName)) {
    case NEW:
    case FORCED:
    case NO_CHANGE:
        // A successful update of the reference
        break;
    default:
        // Handle the failure, e.g. for older behavior
        throw new IOException(u.getResult());
    }

Change-Id: I1093e1ec2970147978a786cfdd0a75d0aebf8010
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>

This commit actually does three major changes to the way references
are handled within JGit.  Unfortunately they were easier to do as
a single massive commit than to break them up into smaller units.

Disambiguate symbolic references:
---------------------------------

  Reporting a symbolic reference such as HEAD as though it were
  any other normal reference like refs/heads/master causes subtle
  programming errors.  We have been bitten by this error on several
  occasions, as have some downstream applications written by myself.

  Instead of reporting HEAD as a reference whose name differs from
  its "original name", report it as an actual SymbolicRef object
  that the application can test the type and examine the target of.

  With this change, Ref is now an abstract type with different
  subclasses for the different types.

  In the classical example of "HEAD" being a symbolic reference to
  branch "refs/heads/master", the Repository.getAllRefs() method
  will now return:

      Map<String, Ref> all = repository.getAllRefs();
      SymbolicRef HEAD = (SymbolicRef) all.get("HEAD");
      ObjectIdRef master = (ObjectIdRef) all.get("refs/heads/master");

      assertSame(master,               HEAD.getTarget());
      assertSame(master.getObjectId(), HEAD.getObjectId());

      assertEquals("HEAD",              HEAD.getName());
      assertEquals("refs/heads/master", master.getName());

  A nice side-effect of this change is the storage type of the
  symbolic reference is no longer ambiguous with the storge type
  of the underlying reference it targets.  In the above example,
  if master was only available in the packed-refs file, then the
  following is also true:

      assertSame(Ref.Storage.LOOSE,  HEAD.getStorage());
      assertSame(Ref.Storage.PACKED, master.getStorage());

  (Prior to this change we returned the ambiguous storage of
   LOOSE_PACKED for HEAD, which was confusing since it wasn't
   actually true on disk).

  Another nice side-effect of this change is all intermediate
  symbolic references are preserved, and are therefore visible
  to the application when they walk the target chain.  We can
  now correctly inspect chains of symbolic references.

  As a result of this change the Ref.getOrigName() method has been
  removed from the API.  Applications should identify a symbolic
  reference by testing for isSymbolic() and not by using an arcane
  string comparsion between properties.

Abstract the RefDatabase storage:
---------------------------------

  RefDatabase is now abstract, similar to ObjectDatabase, and a
  new concrete implementation called RefDirectory is used for the
  traditional on-disk storage layout.  In the future we plan to
  support additional implementations, such as a pure in-memory
  RefDatabase for unit testing purposes.

Optimize RefDirectory:
----------------------

  The implementation of the in-memory reference cache, reading, and
  update routines has been completely rewritten.  Much of the code
  was heavily borrowed or cribbed from the prior implementation,
  so copyright notices have been left intact as much as possible.

  The RefDirectory cache no longer confuses symbolic references
  with normal references.  This permits the cache to resolve the
  value of a symbolic reference as late as possible, ensuring it
  is always current, without needing to maintain reverse pointers.

  The cache is now 2 sorted RefLists, rather than 3 HashMaps.
  Using sorted lists allows the implementation to reduce the
  in-memory footprint when storing many refs.  Using specialized
  types for the elements allows the code to avoid additional map
  lookups for auxiliary stat information.

  To improve scan time during getRefs(), the lists are returned via
  a copy-on-write contract.  Most callers of getRefs() do not modify
  the returned collections, so the copy-on-write semantics improves
  access on repositories with a large number of packed references.

  Iterator traversals of the returned Map<String,Ref> are performed
  using a simple merge-join of the two cache lists, ensuring we can
  perform the entire traversal in linear time as a function of the
  number of references: O(PackedRefs + LooseRefs).

  Scans of the loose reference space to update the cache run in
  O(LooseRefs log LooseRefs) time, as the directory contents
  are sorted before being merged against the in-memory cache.
  Since the majority of stable references are kept packed, there
  typically are only a handful of reference names to be sorted,
  so the sorting cost should not be very high.

  Locking is reduced during getRefs() by taking advantage of the
  copy-on-write semantics of the improved cache data structure.
  This permits concurrent readers to pull back references without
  blocking each other.  If there is contention updating the cache
  during a scan, one or more updates are simply skipped and will
  get picked up again in a future scan.

  Writing to the $GIT_DIR/packed-refs during reference delete is
  now fully atomic.  The file is locked, reparsed fresh, and written
  back out if a change is necessary.  This avoids all race conditions
  with concurrent external updates of the packed-refs file.

  The RefLogWriter class has been fully folded into RefDirectory
  and is therefore deleted.  Maintaining the reference's log is
  the responsiblity of the database implementation, and not all
  implementations will use java.io for access.

  Future work still remains to be done to abstract the ReflogReader
  class away from local disk IO.

Change-Id: I26b9287c45a4b2d2be35ba2849daa316f5eec85d
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>

These types can be used by RefDatabase implementations to manage
the collection.

A RefList stores items sorted by their name, and is an immutable
type using copy-on-write semantics to perform modifications to
the collection.  Binary search is used to locate an existing item
by name, or to locate the proper insertion position if an item does
not exist.

A RefMap can merge up to 3 RefList collections at once during its
entry iteration, allowing items in the resolved or loose RefList
to override items by the same name in the packed RefList.

The RefMap's goal is O(log N) lookup time, and O(N) iteration time,
which is suitable for returning from a RefDatabase.  By relying on
the immutable RefList we might be able to make map construction
nearly constant, making Repository.getAllRefs() an inexpensive
operation if the caches are current.  Since modification is not
common, changes require up to O(N + log N) time to copy the internal
list and collapse or expand the list's array.  As most changes
are made to the loose collection and not the packed collection,
in practice most changes would require less than the full O(N)
time, due to a significantly smaller N in the loose list.

Almost complete test coverage is included in the corresponding
unit tests.  A handful of methods on RefMap are not tested in this
change, as writing the proper test depends on a future refactoring
of how the Ref class represents symbolic reference names.

Change-Id: Ic2095274000336556f719edd75a5c5dd6dd1d857
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>

On Windows systems, file system lookup is a slow operation, so
checking each object if it exists during indexing (after receiving
the pack) could take a siginificant time. This patch introduces
CachedObjectDirectory that pre-caches lookup results.

Bug: 300397
Change-Id: I471b93f9bb3ee173eb37cae1d75e9e4eb49985e7
Signed-off-by: Constantine Plotnikov <constantine.plotnikov@gmail.com>
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>

Change-Id: Icfe9205994c6810fcd880054a586e9eef29df9a1
Signed-off-by: Robin Rosenberg <robin.rosenberg@dewire.com>

Not all occurrences of ".git" are replaced by this constant, only
those where it actually refers to the directory with that name, i.e
not the ".git" directory suffix.

Asserts and comment are also excluded from replacement.

Change-Id: I65a9da89aedd53817f2ea3eaab4f9c2bed35d7ee
Signed-off-by: Robin Rosenberg <robin.rosenberg@dewire.com>

This is a simple HTTP server that provides the minimum server side
support required for dumb (non-git aware) transport clients.

We produce the info/refs and objects/info/packs file on the fly
from the local repository state, but otherwise serve data as raw
files from the on-disk structure.

In the future we could better optimize the FileSender class and the
servlets that use it to take advantage of direct file to network
APIs in more advanced servlet containers like Jetty.

Our glue package borrows the idea of a micro embedded DSL from
Google Guice and uses it to configure a collection of Filters
and HttpServlets, all of which are matched against requests using
regular expressions.  If a subgroup exists in the pattern, it is
extracted and used for the path info component of the request.

Change-Id: Ia0f1a425d07d035e344ae54faf8aeb04763e7487
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>

Under unit tests we want the when and timezone to come from the
MockSystemReader and be stable.  We did this for the default
constructor based on the Repository, but failed to do it for the
name,emailAddress variant of the constructor.

Change-Id: I608ac7cf01673729303395e19b379b38fef136b3
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>

We really mean to omit HEAD here, but botched the difference between
getOrigName and getName on the Ref object.  We tested on the wrong
value, picking up the target of the symbolic ref and therefore
included it twice.

Change-Id: If780c65166ccada2e63a4f42bbab752a56b16564
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>

The C Git documentation stated that the core.worktree config was
not read when the .git directory was found implicitly (from the
working directory).

This was not true, and had not been so for a long time. The
documentation has been updated to document the existing behaviour.

Change-Id: If1e81b6a981b9d70e849f24872f01c110e9bc950
Signed-off-by: Robin Rosenberg <robin.rosenberg@dewire.com>
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>

Deflater can use significant amount of native (i.e. C) heap
space. Failure to promptly release this memory results
in native memory leak in some cases, particularly severe for
VMs with large java max heap size. For example, running
Team->Commit in one of my EGit workspaces results in ~500M
java process size increase without any significant change
to amount of used java heap when JVM is started with -Xmx1024m.

Change-Id: I649679a8df5683ebedd9380d703513d31c625932
Signed-off-by: Igor Fedorenko <igor@ifedorenko.com>
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>

This exposes the list of known packs, allowing callers to list them
into a context like the objects/info/packs file.

Change-Id: I0b889564bd176836ff5c77ba310c6d229409dcd5
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>

This makes the jgit command line behave like the C Git implementation
in the respect.

These variables are not recognized in the core, though we add support
to do the overrides there. Hence other users of the JGit library, like
the Eclipse plugin and others, will not be affected.

GIT_DIR
	The location of the ".git" directory.

GIT_WORK_TREE
	The location of the work tree.

GIT_INDEX_FILE
	The location of the index file.

GIT_CEILING_DIRECTORIES
	A colon (semicolon on Windows) separated list of paths that
	which JGit will not cross when looking for the .git directory.

GIT_OBJECT_DIRECTORY
	The location of the objects directory under which objects are
	stored.

GIT_ALTERNATE_OBJECT_DIRECTORIES
	A colon (semicolon on Windows) separated list of object directories
	to search for objects.

In addition to these we support the core.worktree config setting when
the git directory is set deliberately instead of being found.

Change-Id: I2b9bceb13c0f66b25e9e3cefd2e01534a286e04c
Signed-off-by: Robin Rosenberg <robin.rosenberg@dewire.com>
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>

An extra flag when creating a RefUpdate object allows the
caller to destroy the symref and replace it with an object
ref, a.k.a. detached HEAD.

Change-Id: Ia88d48eab1eb4861ebfa39e3be9258c3824a19db
Signed-off-by: Robin Rosenberg <robin.rosenberg@dewire.com>
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>

A few locations were doing OBJECT_ID_LENGTH * 2 on their own, as
the old STR_LEN constant wasn't visible.  Replace them with the
new public constant OBJECT_ID_STRING_LENGTH.

Change-Id: Id39bddb52de8c65bb097de042e9d4ed99598201f
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>

Since Constants.OBJECT_ID_LENGTH is a compile time constant we
can be sure that it will always be inlined. The same goes for the
associated constant STR_LEN which is now refactored to the Constant
class and given a name better suited for wider use.

Change-Id: I03f52131e64edcd0aa74bbbf36e7d42faaf4a698
Signed-off-by: Robin Rosenberg <robin.rosenberg@dewire.com>

Change-Id: I4e369382b8a83a5c0772462d1b176b1e23910ada

For historical reasons JGit was creating .git/remotes folder when
initialization an empty repository.  However, this folder is never
used and the new Git repository format doesn't contain them.

Removed the unnecessary remotes folder creation, it was removed from
C Git in 75c384efb5 ("Do not create $GIT_DIR/remotes/ directory
anymore") by Junio C Hamano on Dec 19 2006.  C Git hasn't made it
for almost 3 years.

Change-Id: I5473f3676a3642afdf9aaac44b7e6319c6e170b9
Signed-off-by: Sasa Zivkov <sasa.zivkov@sap.com>
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>

According the javadoc, and implied by the name of the class, NB
is about network byte order. The purpose of moving the IO only,
and non-byte order related functions to another class is to
make it easier for new contributors to understand that they
can use these functions in general and it's also makes it easier
to understand where to put new IO related utility functions

Change-Id: I4a9f6b39d5564bc8a694b366e7ff3cc758c5181b
Signed-off-by: Robin Rosenberg <robin.rosenberg@dewire.com>
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>

As discussed on the egit-dev mailing list, we prefer not to have
trailing whitespace in our source code.  Correct all currently
offending lines by trimming them.

Change-Id: I002b1d1980071084c0bc53242c8f5900970e6845
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>

Bug: 291133
Change-Id: I24272d029cff446ffc80063870478577d628f338
Reviewed-by: Alex Blewitt <alex.blewitt@gmail.com>
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>

When reading commits the system default encoding was used if no
encoding was specified in the commit. The patch modifies the test
to add a check that commit message was encoded correctly (the
test fails on old implementation if system encoding is not UTF-8)
and fixes Commit.decode() method to use UTF-8 if encoding is not
specified in the commit object.

Change-Id: I27101da3c2eb6edd0c4a9e4c0523e48b286e3cd5
Signed-off-by: Constantine Plotnikov <constantine.plotnikov@gmail.com>
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>

Honor the configuration parameter core.logAllRefUpdates when writing
reflogs.  Instead of writing reflog entries always only write
reflogs if this parameter is set to true or if the corresponding
file in the <git-dir>/logs directory already exists. In other words:
if you are updating a ref and this parameter is set to false and
there is no file corresponding to your ref in the <git-dir>/logs
folder then no reflog will be written.

This is a fix for the issue http://code.google.com/p/egit/issues/detail?id=4

Change-Id: I908e4c77e3630dc3223b2d2a47cb4534dbe4ed42
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>
Signed-off-by: Christian Halstrick <christian.halstrick@sap.com>
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>

Per CQ 3448 this is the initial contribution of the JGit project
to eclipse.org.  It is derived from the historical JGit repository
at commit 3a2dd9921c.

Signed-off-by: Shawn O. Pearce <spearce@spearce.org>