Re: [PATCH 2/2] archive: support gzipped tar files

Creating gzipped archives is of course more expensive than
regular tar archives; however, the amount of work should be
comparable to that of creating a zip file, which is already
possible. So there should be no new security implications
with respect to creating load on a remote server.

Signed-off-by: Jeff King <redacted>
---
 Documentation/git-archive.txt |   17 +++++++++++++++--
 archive-tar.c                 |   27 +++++++++++++++++++++++++++
 archive.c                     |    1 +
 archive.h                     |    1 +
 builtin/archive.c             |    6 ++++++
 t/t5000-tar-tree.sh           |   26 ++++++++++++++++++++++++++
 6 files changed, 76 insertions(+), 2 deletions(-)

diff --git a/Documentation/git-archive.txt b/Documentation/git-archive.txt
index 9c750e2..963bec4 100644
--- a/Documentation/git-archive.txt
+++ b/Documentation/git-archive.txt

@@ -34,10 +34,11 @@ OPTIONS
 -------
 
 --format=<fmt>::
-	Format of the resulting archive: 'tar' or 'zip'. If this option
+	Format of the resulting archive: 'tar', 'tgz', or 'zip'. If this option
 	is not given, and the output file is specified, the format is
 	inferred from the filename if possible (e.g. writing to "foo.zip"
-	makes the output to be in the zip format). Otherwise the output
+	creates the output in the zip format; "foo.tgz" or "foo.tar.gz"
+	creates the output in the tgz format). Otherwise the output
 	format is `tar`.
 
 -l::

@@ -89,6 +90,12 @@ zip
 	Highest and slowest compression level.  You can specify any
 	number from 1 to 9 to adjust compression speed and ratio.
 
+tgz
+~~~
+-9::
+	Highest and slowest compression level. You can specify any
+	number from 1 to 9 to adjust compression speed and ratio.
+
 
 CONFIGURATION
 -------------

@@ -133,6 +140,12 @@ git archive --format=tar --prefix=git-1.4.0/ v1.4.0 | gzip >git-1.4.0.tar.gz::
 
 	Create a compressed tarball for v1.4.0 release.
 
+git archive --prefix=git-1.4.0/ -o git-1.4.0.tar.gz v1.4.0
+
+	Same as above, except that we use the internal gzip. Note that
+	the output format is inferred by the extension of the output
+	file.
+
 git archive --format=tar --prefix=git-1.4.0/ v1.4.0{caret}\{tree\} | gzip >git-1.4.0.tar.gz::
 
 	Create a compressed tarball for v1.4.0 release, but without a

diff --git a/archive-tar.c b/archive-tar.c
index b1aea87..86c8aa9 100644
--- a/archive-tar.c
+++ b/archive-tar.c

@@ -260,3 +260,30 @@ int write_tar_archive(struct archiver_args *args)
 	output = output_write;
 	return write_tar_archive_internal(args);
 }
+
+static gzFile gz_file;
+static void output_gz(const char *buf, unsigned long len)
+{
+	if (!gzwrite(gz_file, buf, len))
+		die("unable to write compressed stream: %s",
+		    gzerror(gz_file, NULL));
+}