delta/git.git/sideband.c, branch hv/mv-nested-submodules-test

Merge branch 'lf/recv-sideband-cleanup'

2016-07-19T20:22:14+00:00

Code simplification.

* lf/recv-sideband-cleanup:
  sideband.c: small optimization of strbuf usage
  sideband.c: refactor recv_sideband()

sideband.c: small optimization of strbuf usage

2016-07-06T21:09:32+00:00

Signed-off-by: Nicolas Pitre 
Signed-off-by: Junio C Hamano

sideband.c: refactor recv_sideband()

2016-07-01T20:09:37+00:00

We used character buffer manipulations to split messages from the
sideband at line breaks and insert "remote: " at the beginning of
each line, using the packet size to determine the end of a message.

However, since it is safe to assume that diagnostic messages from
the sideband never contain NUL characters, we can also NUL-terminate
the buffer, use strpbrk() for splitting lines and use format strings
to insert the prefix, to make the code easier to read and maintain.

A strbuf is used for accumulating the output which is then printed
using a single write(2) call to ensure the atomicity of the output.
See 9ac13ec (atomic write for sideband remote messages, 2006-10-11)
for details.

Helped-by: Jeff King 
Helped-by: Junio C Hamano 
Helped-by: Nicolas Pitre 
Signed-off-by: Lukas Fleischer 
Signed-off-by: Junio C Hamano

sideband.c: make send_sideband() return void

2016-06-16T18:40:19+00:00

The send_sideband() function uses write_or_die() for writing data which
immediately terminates the process on errors. If no such error occurred,
send_sideband() always returned the value that was passed as fourth
parameter prior to this commit. This value is already known to the
caller in any case, so let's turn send_sideband() into a void function
instead.

Signed-off-by: Lukas Fleischer 
Signed-off-by: Junio C Hamano

convert trivial sprintf / strcpy calls to xsnprintf

2015-09-25T17:18:18+00:00

We sometimes sprintf into fixed-size buffers when we know
that the buffer is large enough to fit the input (either
because it's a constant, or because it's numeric input that
is bounded in size). Likewise with strcpy of constant
strings.

However, these sites make it hard to audit sprintf and
strcpy calls for buffer overflows, as a reader has to
cross-reference the size of the array with the input. Let's
use xsnprintf instead, which communicates to a reader that
we don't expect this to overflow (and catches the mistake in
case we do).

Signed-off-by: Jeff King 
Signed-off-by: Junio C Hamano

sideband.c: do not use ANSI control sequence on non-terminal

2014-06-02T18:02:27+00:00

Diagnostic messages received on the sideband #2 from the server side
are sent to the standard error with ANSI terminal control sequence
"\033[K" that erases to the end of line appended at the end of each
line.

However, some programs (e.g. GitExtensions for Windows) read and
interpret and/or show the message without understanding the terminal
control sequences, resulting them to be shown to their end users.
To help these programs, squelch the control sequence when the
standard error stream is not being sent to a tty.

NOTE: I considered to cover the case that a pager has already been
started. But decided that is probably not worth worrying about here,
though, as we shouldn't be using a pager for commands that do network
communications (and if we do, omitting the magic line-clearing signal
is probably a sane thing to do).

Thanks-to: Erik Faye-Lund 
Thanks-to: Jeff King 
Signed-off-by: Michael Naumov 
Signed-off-by: Junio C Hamano

pkt-line: share buffer/descriptor reading implementation

2013-02-24T08:14:15+00:00

The packet_read function reads from a descriptor. The
packet_get_line function is similar, but reads from an
in-memory buffer, and uses a completely separate
implementation. This patch teaches the generic packet_read
function to accept either source, and we can do away with
packet_get_line's implementation.

There are two other differences to account for between the
old and new functions. The first is that we used to read
into a strbuf, but now read into a fixed size buffer. The
only two callers are fine with that, and in fact it
simplifies their code, since they can use the same
static-buffer interface as the rest of the packet_read_line
callers (and we provide a similar convenience wrapper for
reading from a buffer rather than a descriptor).

This is technically an externally-visible behavior change in
that we used to accept arbitrary sized packets up to 65532
bytes, and now cap out at LARGE_PACKET_MAX, 65520. In
practice this doesn't matter, as we use it only for parsing
smart-http headers (of which there is exactly one defined,
and it is small and fixed-size). And any extension headers
would be breaking the protocol to go over LARGE_PACKET_MAX
anyway.

The other difference is that packet_get_line would return
on error rather than dying. However, both callers of
packet_get_line are actually improved by dying.

The first caller does its own error checking, but we can
drop that; as a result, we'll actually get more specific
reporting about protocol breakage when packet_read dies
internally. The only downside is that packet_read will not
print the smart-http URL that failed, but that's not a big
deal; anybody not debugging can already see the remote's URL
already, and anybody debugging would want to run with
GIT_CURL_VERBOSE anyway to see way more information.

The second caller, which is just trying to skip past any
extra smart-http headers (of which there are none defined,
but which we allow to keep room for future expansion), did
not error check at all. As a result, it would treat an error
just like a flush packet. The resulting mess would generally
cause an error later in get_remote_heads, but now we get
error reporting much closer to the source of the problem.

Brown-paper-bag-fixes-by: Ramsay Jones 
Signed-off-by: Jeff King 
Signed-off-by: Junio C Hamano

pkt-line: teach packet_read_line to chomp newlines

2013-02-20T21:42:21+00:00

The packets sent during ref negotiation are all terminated
by newline; even though the code to chomp these newlines is
short, we end up doing it in a lot of places.

This patch teaches packet_read_line to auto-chomp the
trailing newline; this lets us get rid of a lot of inline
chomping code.

As a result, some call-sites which are not reading
line-oriented data (e.g., when reading chunks of packfiles
alongside sideband) transition away from packet_read_line to
the generic packet_read interface. This patch converts all
of the existing callsites.

Since the function signature of packet_read_line does not
change (but its behavior does), there is a possibility of
new callsites being introduced in later commits, silently
introducing an incompatibility.  However, since a later
patch in this series will change the signature, such a
commit would have to be merged directly into this commit,
not to the tip of the series; we can therefore ignore the
issue.

This is an internal cleanup and should produce no change of
behavior in the normal case. However, there is one corner
case to note. Callers of packet_read_line have never been
able to tell the difference between a flush packet ("0000")
and an empty packet ("0004"), as both cause packet_read_line
to return a length of 0. Readers treat them identically,
even though Documentation/technical/protocol-common.txt says
we must not; it also says that implementations should not
send an empty pkt-line.

By stripping out the newline before the result gets to the
caller, we will now treat the newline-only packet ("0005\n")
the same as an empty packet, which in turn gets treated like
a flush packet. In practice this doesn't matter, as neither
empty nor newline-only packets are part of git's protocols
(at least not for the line-oriented bits, and readers who
are not expecting line-oriented packets will be calling
packet_read directly, anyway). But even if we do decide to
care about the distinction later, it is orthogonal to this
patch.  The right place to tighten would be to stop treating
empty packets as flush packets, and this change does not
make doing so any harder.

Signed-off-by: Jeff King 
Signed-off-by: Junio C Hamano

pkt-line: drop safe_write function

2013-02-20T21:42:21+00:00

This is just write_or_die by another name. The one
distinction is that write_or_die will treat EPIPE specially
by suppressing error messages. That's fine, as we die by
SIGPIPE anyway (and in the off chance that it is disabled,
write_or_die will simulate it).

Signed-off-by: Jeff King 
Signed-off-by: Junio C Hamano

Smart push over HTTP: client side

2009-11-05T01:58:15+00:00

The git-remote-curl backend detects if the remote server supports
the git-receive-pack service, and if so, runs git-send-pack in a
pipe to dump the command and pack data as a single POST request.

The advertisements from the server that were obtained during the
discovery are passed into git-send-pack before the POST request
starts.  This permits git-send-pack to operate largely unmodified.

For smaller packs (those under 1 MiB) a HTTP/1.0 POST with a
Content-Length is used, permitting interaction with any server.
The 1 MiB limit is arbitrary, but is sufficent to fit most deltas
created by human authors against text sources with the occasional
small binary file (e.g. few KiB icon image).  The configuration
option http.postBuffer can be used to increase (or shink) this
buffer if the default is not sufficient.

For larger packs which cannot be spooled entirely into the helper's
memory space (due to http.postBuffer being too small), the POST
request requires HTTP/1.1 and sets "Transfer-Encoding: chunked".
This permits the client to upload an unknown amount of data in one
HTTP transaction without needing to pregenerate the entire pack
file locally.

Signed-off-by: Shawn O. Pearce 
CC: Daniel Barkalow 
Signed-off-by: Junio C Hamano