Subject: Re: Commit ID in exported Tar Ball

From: René Scharfe <[email-masked]>
Date: Sat, 19 May 2007 22:22:58 +0200

Frank Lichtenheld schrieb:
> On Thu, May 17, 2007 at 06:57:22PM +0200, Johan Herland wrote:
>> Of course, it all depends on whether the $Id$ conversion is triggered by 
>> git-archive...
> 
> Another possibility might be to add a commandline switch to git-archive
> so you can decide whether the commit id should be added as a header to
> the tar file (which it already supports) or as a ordinary file (which
> should be reasonable trivial to implement). The question if whether
> it would be worth to add that feature. Don't know if there are many
> other users out there that need it.

Something like the following patch?  Since we're already embedding the
commit ID in a comment, we might as well offer creating a synthetic file
for it, too, if that solves a user's problem that might be difficult to
work around otherwise.

René

 Documentation/git-archive.txt |    4 ++++
 archive-tar.c                 |    7 +++++++
 archive-zip.c                 |    7 +++++++
 archive.h                     |    1 +
 builtin-archive.c             |   11 +++++++++++
 5 files changed, 30 insertions(+), 0 deletions(-)

diff --git a/Documentation/git-archive.txt b/Documentation/git-archive.txt
index 721e035..ac31aac 100644
--- a/Documentation/git-archive.txt
+++ b/Documentation/git-archive.txt
@@ -43,6 +43,10 @@ OPTIONS
 --prefix=<prefix>/::
 	Prepend <prefix>/ to each filename in the archive.
 
+--commit-id-file=<filename>::
+	Adds a file to the archive containing the commit ID.  This option
+	is ignored if <tree-ish> references a tree instead of a commit.
+
 <extra>::
 	This can be any options that the archiver backend understand.
 	See next section.
diff --git a/archive-tar.c b/archive-tar.c
index 33e7657..555850a 100644
--- a/archive-tar.c
+++ b/archive-tar.c
@@ -319,6 +319,13 @@ int write_tar_archive(struct archiver_args *args)
 	}
 	read_tree_recursive(args->tree, args->base, plen, 0,
 			    args->pathspec, write_tar_entry);
+	if (args->commit_sha1 && args->commit_sha1_file) {
+		unsigned char fake_sha1[20];
+		pretend_sha1_file(sha1_to_hex(args->commit_sha1), 40,
+		                  OBJ_BLOB, fake_sha1);
+		write_tar_entry(fake_sha1, args->base, plen,
+		                args->commit_sha1_file, 0100666, 0);
+	}
 	write_trailer();
 
 	return 0;
diff --git a/archive-zip.c b/archive-zip.c
index 3cbf6bb..88c5dfa 100644
--- a/archive-zip.c
+++ b/archive-zip.c
@@ -328,6 +328,13 @@ int write_zip_archive(struct archiver_args *args)
 	}
 	read_tree_recursive(args->tree, args->base, plen, 0,
 			    args->pathspec, write_zip_entry);
+	if (args->commit_sha1 && args->commit_sha1_file) {
+		unsigned char fake_sha1[20];
+		pretend_sha1_file(sha1_to_hex(args->commit_sha1), 40,
+		                  OBJ_BLOB, fake_sha1);
+		write_zip_entry(fake_sha1, args->base, plen,
+		                args->commit_sha1_file, 0100666, 0);
+	}
 	write_zip_trailer(args->commit_sha1);
 
 	free(zip_dir);
diff --git a/archive.h b/archive.h
index 6838dc7..020f82f 100644
--- a/archive.h
+++ b/archive.h
@@ -8,6 +8,7 @@ struct archiver_args {
 	const char *base;
 	struct tree *tree;
 	const unsigned char *commit_sha1;
+	const char *commit_sha1_file;
 	time_t time;
 	const char **pathspec;
 	unsigned int verbose : 1;
diff --git a/builtin-archive.c b/builtin-archive.c
index 7f4e409..e58ea16 100644
--- a/builtin-archive.c
+++ b/builtin-archive.c
@@ -151,6 +151,7 @@ int parse_archive_args(int argc, const char **argv, struct archiver *ar)
 	int extra_argc = 0;
 	const char *format = "tar";
 	const char *base = "";
+	const char *commit_sha1_file = NULL;
 	int verbose = 0;
 	int i;
 
@@ -174,6 +175,10 @@ int parse_archive_args(int argc, const char **argv, struct archiver *ar)
 			base = arg + 9;
 			continue;
 		}
+		if (!prefixcmp(arg, "--commit-id-file=")) {
+			commit_sha1_file = arg + 17;
+			continue;
+		}
 		if (!strcmp(arg, "--")) {
 			i++;
 			break;
@@ -192,6 +197,11 @@ int parse_archive_args(int argc, const char **argv, struct archiver *ar)
 		usage(archive_usage);
 	if (init_archiver(format, ar) < 0)
 		die("Unknown archive format '%s'", format);
+	if (commit_sha1_file) {
+		size_t namelen = strlen(commit_sha1_file);
+		if (namelen == 0 || commit_sha1_file[namelen - 1] == '/')
+			die("Invalid commit ID file name: %s", commit_sha1_file);
+	}
 
 	if (extra_argc) {
 		if (!ar->parse_extra)
@@ -201,6 +211,7 @@ int parse_archive_args(int argc, const char **argv, struct archiver *ar)
 	}
 	ar->args.verbose = verbose;
 	ar->args.base = base;
+	ar->args.commit_sha1_file = commit_sha1_file;
 
 	return i;
 }