Doing a keep call with a length of 1 will copy the current entry just
like the previous add was doing, but it avoids doing any validation
on the entry.  This is sane because the entry can be assumed to be
already valid, since its originating from the destination index.

Change-Id: I250d902fc98580444af1ba4b8fedceb654541451
Originally: http://thread.gmane.org/gmane.comp.version-control.git/128214/focus=128213
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>

A 0 file mode in a DirCacheEntry is not a valid mode.  To C git
such a value indicates the record should not be present.  We already
were catching this bad state and exceptioning out when writing tree
objects to disk, but we did not fail when writing the dircache back
to disk.  This allowed JGit applications to create a dircache file
which C git would not like to read.

Instead of checking the mode during writes, we now check during
mutation.  This allows application bugs to be detected sooner and
closer to the cause site.  It also allows us to avoid checking most
of the records which we read in from disk, as we can assume these
are formatted correctly.

Some of our unit tests were not setting the FileMode on their test
entry, so they had to be updated to use REGULAR_FILE.

Change-Id: Ie412053c390b737c0ece57b8e063e4355ee32437
Originally: http://thread.gmane.org/gmane.comp.version-control.git/128214/focus=128213
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
CC: Adam W. Hawks <awhawks@writeme.com>

A dircache record must not use a path string like "/a" or "a//b"
as this results in a tree entry being written with a zero length
name component in the record.  C git does not support an empty name,
and neither does any modern filesystem.

A record also must not have a stage outside of the standard 0-3
value range, as there are only 2 bits of space available in the
on-disk format of the record to store the stage information.
Any other values would be truncated into this space, storing a
different value than the caller expected.

If an application tries to create a DirCache record with either of
these wrong values, we abort with an IllegalArgumentException.

Change-Id: I699de149efdfccd85d8adde07d3efd080e3b49c2
Originally: http://thread.gmane.org/gmane.comp.version-control.git/128214
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
CC: Adam W. Hawks <awhawks@writeme.com>

We didn't skip the correct number of bytes when we skipped over an
unrecognized but optional dircache extension.  We missed skipping
the 8 byte header that makes up the extension's name and length.

We also didn't include the skipped extension's payload as part of
our index checksum, resuting in a checksum failure when the index
was done reading.  So ensure we always scan through a skipped
section and include it in the checksum computation.

Add a test case for a currently unsupported index extension, 'ZZZZ',
to verify we can still read the DirCache object even though we
don't know what 'ZZZZ' is supposed to mean.

Bug: 301287
Change-Id: I4bdde94576fffe826d0782483fd98cab1ea628fa
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>

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>

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>