This avoids the server from referencing the client code directly.

Change-Id: Ie6ade781b5a689646ad8b0b2988ef2b544412195

For streams that should not be closed, i.e. don't own an underlying
stream, and in-memory streams that do not need to be closed we just
suppress the warning. This mostly apply to test cases. GC is enough.

For streams with external resources (i.e. files) we add the necessary
call to close().

Change-Id: I4d883ba2e7d07f199fe57ccb3459ece00441a570

The fetch-pack/upload-pack stream usually has an LF at the
end of the first "want" line. Trim this when checking to
see if side-band or side-band-64k was used.

Perform the same trim for send-pack/receive-pack, as it is
harmless in this context to ignore an LF just before doing
an error report.

Change-Id: I6ef946bb6124fa72c52bd5320187eaac3ed906e7

When a client POSTs to /git-{upload,receive}-pack, the first line
includes their client capabilities. As soon as the C git client sends
side-band(-64k), it goes into a state where it chokes on data not sent
in a valid sideband channel.

GitSmartHttpTools.sendError() is called early in the request, likely
before a {Upload,Receive}Pack handler is assigned or, even so, before it
has read the request. In some cases we must read the first line manually
within sendError() to tell whether sideband is needed.

Change-Id: I8277fd45a4ec3b71fa8f87404b4f5d1a09e0f384

The HTTP RFCs require a server to fully consume the request body before
it can return a non-error status code, which is any code below 400.

JGit returns most Git level errors inside of an HTTP 200 OK response,
and sometimes this happens before the entire request was consumed from
the servlet container. In such cases the body must be skipped or read
until EOF is reached, ensuring the HTTP keep-alive semantics will work
for the next request on the same TCP connection.

HTTP status codes >= 400 may be returned without consuming the body,
and a servlet container must set "Connection: close" in the response
headers when this happens, since the state of the request body is not
well defined with an early abort.

With the introduction of sendError() in GitSmartHttpTools there are
only a handful of locations that need to worry about the request body
being consumed, so sprinkle the call in as necessary.

Change-Id: I5381e110585f780c01a764df8e27c80aacf5146e

The GitSmartHttpTools class started as utility functions to help report
useful error messages to users of the android.googlesource.com service.

Now that the GitServlet and GitFilter classes support filters before a
git-upload-pack or git-receive-pack request, server implementors may
these routines helpful to report custom messages to clients.  Using the
sendError() method to return an HTTP 200 OK with error text embedded in
the payload prevents native Git clients from retrying the action with a
dumb Git or WebDAV HTTP request.

Refactor some of the existing code to use these new error functions and
protocol constants.  The new sendError() function is very close to being
identical to the old error handling code in RepositoryFilter, however we
now use the POST Content-Type rather than the Accept HTTP header to check
if the client will accept the error data in the response body rather than
using the HTTP status code.  This is a more reliable way of checking for
native Git clients, as the Accept header was not always populated with the
correct string in older versions of Git smart HTTP.

Change-Id: I828ac2deb085af12b6689c10f86662ddd39bd1a2