[PATCH 2/4] http-fetch: allow custom index-pack args

[Jonathan Tan <jonathantanmy@google.com>]

This is the next step in teaching fetch-pack to pass its index-pack
arguments when processing packfiles referenced by URIs.

The "--keep" in fetch-pack.c will be replaced with a full message in a
subsequent commit.

Signed-off-by: Jonathan Tan <jonathantanmy@google.com>
---
 Documentation/git-http-fetch.txt |  9 ++++++--
 fetch-pack.c                     |  1 +
 http-fetch.c                     | 35 +++++++++++++++++++++++++++-----
 t/t5550-http-fetch-dumb.sh       |  3 ++-
 4 files changed, 40 insertions(+), 8 deletions(-)

diff --git a/Documentation/git-http-fetch.txt b/Documentation/git-http-fetch.txt
index 4deb4893f5..aa171088e8 100644
--- a/Documentation/git-http-fetch.txt
+++ b/Documentation/git-http-fetch.txt
@@ -41,11 +41,16 @@ commit-id::
 		<commit-id>['\t'<filename-as-in--w>]
 
 --packfile=<hash>::
-	Instead of a commit id on the command line (which is not expected in
+	For internal use only. Instead of a commit id on the command line (which is not expected in
 	this case), 'git http-fetch' fetches the packfile directly at the given
 	URL and uses index-pack to generate corresponding .idx and .keep files.
 	The hash is used to determine the name of the temporary file and is
-	arbitrary. The output of index-pack is printed to stdout.
+	arbitrary. The output of index-pack is printed to stdout. Requires
+	--index-pack-args.
+
+--index-pack-args=<args>::
+	For internal use only. The command to run on the contents of the
+	downloaded pack. Arguments are URL-encoded separated by spaces.
 
 --recover::
 	Verify that everything reachable from target is fetched.  Used after
diff --git a/fetch-pack.c b/fetch-pack.c
index 876f90c759..274ae602f7 100644
--- a/fetch-pack.c
+++ b/fetch-pack.c
@@ -1645,6 +1645,7 @@ static struct ref *do_fetch_pack_v2(struct fetch_pack_args *args,
 		strvec_pushf(&cmd.args, "--packfile=%.*s",
 			     (int) the_hash_algo->hexsz,
 			     packfile_uris.items[i].string);
+		strvec_push(&cmd.args, "--index-pack-args=index-pack --stdin --keep");
 		strvec_push(&cmd.args, uri);
 		cmd.git_cmd = 1;
 		cmd.no_stdin = 1;
diff --git a/http-fetch.c b/http-fetch.c
index 2d1d9d054f..12feb84e71 100644
--- a/http-fetch.c
+++ b/http-fetch.c
@@ -3,6 +3,7 @@
 #include "exec-cmd.h"
 #include "http.h"
 #include "walker.h"
+#include "strvec.h"
 
 static const char http_fetch_usage[] = "git http-fetch "
 "[-c] [-t] [-a] [-v] [--recover] [-w ref] [--stdin | --packfile=hash | commit-id] url";
@@ -43,11 +44,9 @@ static int fetch_using_walker(const char *raw_url, int get_verbosely,
 	return rc;
 }
 
-static const char *index_pack_args[] =
-	{"index-pack", "--stdin", "--keep", NULL};
-
 static void fetch_single_packfile(struct object_id *packfile_hash,
-				  const char *url) {
+				  const char *url,
+				  const char **index_pack_args) {
 	struct http_pack_request *preq;
 	struct slot_results results;
 	int ret;
@@ -90,6 +89,7 @@ int cmd_main(int argc, const char **argv)
 	int packfile = 0;
 	int nongit;
 	struct object_id packfile_hash;
+	const char *index_pack_args = NULL;
 
 	setup_git_directory_gently(&nongit);
 
@@ -116,6 +116,8 @@ int cmd_main(int argc, const char **argv)
 			packfile = 1;
 			if (parse_oid_hex(p, &packfile_hash, &end) || *end)
 				die(_("argument to --packfile must be a valid hash (got '%s')"), p);
+		} else if (skip_prefix(argv[arg], "--index-pack-args=", &p)) {
+			index_pack_args = p;
 		}
 		arg++;
 	}
@@ -128,10 +130,33 @@ int cmd_main(int argc, const char **argv)
 	git_config(git_default_config, NULL);
 
 	if (packfile) {
-		fetch_single_packfile(&packfile_hash, argv[arg]);
+		struct strvec encoded = STRVEC_INIT;
+		char **raw;
+		int i;
+
+		if (!index_pack_args)
+			die(_("--packfile requires --index-pack-args"));
+
+		strvec_split(&encoded, index_pack_args);
+
+		CALLOC_ARRAY(raw, encoded.nr + 1);
+		for (i = 0; i < encoded.nr; i++)
+			raw[i] = url_percent_decode(encoded.v[i]);
+
+		fetch_single_packfile(&packfile_hash, argv[arg],
+				      (const char **) raw);
+
+		for (i = 0; i < encoded.nr; i++)
+			free(raw[i]);
+		free(raw);
+		strvec_clear(&encoded);
+
 		return 0;
 	}
 
+	if (index_pack_args)
+		die(_("--index-pack-args can only be used with --packfile"));
+
 	if (commits_on_stdin) {
 		commits = walker_targets_stdin(&commit_id, &write_ref);
 	} else {
diff --git a/t/t5550-http-fetch-dumb.sh b/t/t5550-http-fetch-dumb.sh
index 483578b2d7..af90e7efed 100755
--- a/t/t5550-http-fetch-dumb.sh
+++ b/t/t5550-http-fetch-dumb.sh
@@ -224,7 +224,8 @@ test_expect_success 'http-fetch --packfile' '
 
 	git init packfileclient &&
 	p=$(cd "$HTTPD_DOCUMENT_ROOT_PATH"/repo_pack.git && ls objects/pack/pack-*.pack) &&
-	git -C packfileclient http-fetch --packfile=$ARBITRARY "$HTTPD_URL"/dumb/repo_pack.git/$p >out &&
+	git -C packfileclient http-fetch --packfile=$ARBITRARY \
+		--index-pack-args="index-pack --stdin --keep" "$HTTPD_URL"/dumb/repo_pack.git/$p >out &&
 
 	grep "^keep.[0-9a-f]\{16,\}$" out &&
 	cut -c6- out >packhash &&
-- 
2.30.0.280.ga3ce27912f-goog