The java.io.File methods for creating directories report failure by
returning false. To ease proper checking of return values provide
utility methods wrapping mkdir() and mkdirs() which throw IOException
on failure.

Also fix the tests to store test data under a trash folder and cleanup
after test.

Change-Id: I09c7f9909caf7e25feabda9d31e21ce154e7fcd5
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>
Signed-off-by: Chris Aniszczyk <caniszczyk@gmail.com>

For convenience provide an option to skip deletion of non-existing
files. Also add some tests for deletion methods in FileUtils.

Change-Id: I33e355cfcdc19367d50208150ee49a4a06394890
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>

Change-Id: I22ef1eb63ae8ddb9884526099013979856ab7bd9
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>

We shouldn't escape non-special ASCII characters such as '@' or '~'.
These are valid in a path name on POSIX systems, and may appear as
part of a path in a GNU or Git style patch script.  Escaping them
into octal just obfuscates the user's intent, with no gain.

When parsing an escaped octal sequence, we must parse no more
than 3 digits.  That is, "\1002" is actually "@2", not the Unicode
character \u0202.

Change-Id: I3a849a0d318e69b654f03fd559f5d7f99dd63e5c
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>

Change-Id: I3ad3533d03990c9e84186e53b9d755784b2a3758
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>

PersonIdent should be parsable for an invalid commit which
contains multiple authors, like "A <a@a.org>, B <b@b.org>".
PersonIdent(String) constructor now delegates to
RawParseUtils.parsePersonIdent().

Change-Id: Ie9798d36d9ecfcc0094ca795f5a44b003136eaf7

WorkingTreeIterator now optionally performs CRLF to LF conversion for
text files.  A basic framework is left in place to support enabling
(or disabling) this feature based on gitattributes, and also to
support the more generic smudge/clean filter system.  As there is
no gitattribute support yet in JGit this is left unimplemented,
but the mightNeedCleaning(), isBinary() and filterClean() methods
will provide reasonable places to plug that into in the future.

[sp: All bugs inside of WorkingTreeIterator are my fault, I wrote
     most of it while cherry-picking this patch and building it on
     top of Marc's original work.]

CQ: 4419
Bug: 301775
Change-Id: I0ca35cfbfe3f503729cbfc1d5034ad4abcd1097e
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>

It is useful to be able to replace an existing Change-Id
in the message, for example if the user decides not to
amend the previous commit.

Bug: 321188
Change-Id: I594e7f9efd0c57d794d2bd26d55ec45f4e6a47fd
Signed-off-by: Stefan Lay <stefan.lay@sap.com>
Signed-off-by: Chris Aniszczyk <caniszczyk@gmail.com>

JGit did not have support for skipping whitespace when comparing
lines in RawText objects. I added a subclass of RawText that skips
whitespace in its equals and hashCode methods. I used a subclass
rather than adding functionality into RawText so that performance
would not be impacted by extra logic.

This class only supports ignoring all whitespace. Others will follow
that allow other forms of whitespace ignoring.

Change-Id: Ic2f79e85215e48d3fd53ec1b4ad13373dd183a4a

A Change-Id helps tools like Gerrit Code Review to keeps different
versions of a patch together. The Change-Id is computed as a SHA-1
hash of some of the same basic information as a commit id on the first
commit intended to solve a particular problem and then reused for
updated solutions.

Change-Id: I04334f84e76e83a4185283cb72ea0308b1cb4182
Signed-off-by: Robin Rosenberg <robin.rosenberg@dewire.com>

RawParseUtils.parsePersonIdent handles now those invalid byte sequences
which would result in IndexOutOfBoundsException and returns null in this
case.

If the build server is really busy, we might wait longer than 250 ms
before being interrupted, simply because one of our threads couldn't
be scheduled onto a CPU.  Don't make that cause a test failure.
Instead tolerate longer than expected waits, but not shorter waits.

Change-Id: I64511eec24b49e33928451e4c8b8c124eddaf0c2
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>

Later we are going to add support for smart HTTP, which requires us to
buffer at least some of the request created by a client before we ship
it to the server.  For many requests, we can fit it completely into a
1 MiB buffer, but if it doesn't we can drop back to using the chunked
transfer encoding to send an unknown stream length.

Rather than recoding the block based memory buffer, we refactor the
local file overflow strategy into a subclass, allowing the HTTP client
code to replace this portion of the logic with its own approach to
start the chunked encoding request.

Change-Id: Iac61ea1017b14e0ad3c4425efc3d75718b71bb8e
Signed-off-by: Shawn O. Pearce <sop@google.com>

Other test suites may find this useful, especially when trying
to defeat the pack file compression with random data files.

Change-Id: Ic00a4ac626af7a1c94d18ee99305e295b267b1a3
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>

The UnionInputStream utility class combines multiple sequential
InputStreams so they appear to the caller as a single stream with
no gaps.  This can be used to concentate streams coming from multiple
independent HTTP connections (for example).

The companion unit test covers the class's full functionality.

Change-Id: I0676c7b5e082a5886bf0e8f43f9fd6c46a666228
Signed-off-by: Shawn O. Pearce <sop@google.com>

Add some tests which make sure that the diff algorithm really behaves in the
promised O(N*D) manner. This tests compute diffs between multiple big chunks
of data, measure time for computing the diffs and fail if the measured times
are off O(N*D) by more than a factor 10

Signed-off-by: Christian Halstrick <christian.halstrick@sap.com>
Change-Id: I8e1e0be60299472828718371b231f1d8a9dc21a7
Signed-off-by: Robin Rosenberg <robin.rosenberg@dewire.com>

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>

Some applications may wish to modify an int list.

Bug: 291083
Eclipse-CQ: 3559
Change-Id: Iea871443ec661230aec92397229f1eda6c74216f
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
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>